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-rw-r--r--debian/patches/gssapi.patch4002
1 files changed, 4002 insertions, 0 deletions
diff --git a/debian/patches/gssapi.patch b/debian/patches/gssapi.patch
new file mode 100644
index 000000000..d779eacb6
--- /dev/null
+++ b/debian/patches/gssapi.patch
@@ -0,0 +1,4002 @@
1From d1b7918f9bce6e997c7952ac795e18d09192b2a6 Mon Sep 17 00:00:00 2001
2From: Simon Wilkinson <simon@sxw.org.uk>
3Date: Sun, 9 Feb 2014 16:09:48 +0000
4Subject: GSSAPI key exchange support
5
6This patch has been rejected upstream: "None of the OpenSSH developers are
7in favour of adding this, and this situation has not changed for several
8years. This is not a slight on Simon's patch, which is of fine quality, but
9just that a) we don't trust GSSAPI implementations that much and b) we don't
10like adding new KEX since they are pre-auth attack surface. This one is
11particularly scary, since it requires hooks out to typically root-owned
12system resources."
13
14However, quite a lot of people rely on this in Debian, and it's better to
15have it merged into the main openssh package rather than having separate
16-krb5 packages (as we used to have). It seems to have a generally good
17security history.
18
19Author: Simon Wilkinson <simon@sxw.org.uk>
20Author: Colin Watson <cjwatson@debian.org>
21Author: Jakub Jelen <jjelen@redhat.com>
22Origin: other, https://github.com/openssh-gsskex/openssh-gsskex/commits/debian/master
23Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
24Last-Updated: 2020-06-07
25
26Patch-Name: gssapi.patch
27---
28 Makefile.in | 3 +-
29 README.md | 33 +++
30 auth.c | 96 +-------
31 auth2-gss.c | 56 ++++-
32 auth2.c | 2 +
33 canohost.c | 93 ++++++++
34 canohost.h | 3 +
35 clientloop.c | 15 +-
36 configure.ac | 24 ++
37 gss-genr.c | 300 +++++++++++++++++++++++-
38 gss-serv-krb5.c | 85 ++++++-
39 gss-serv.c | 186 +++++++++++++--
40 kex.c | 66 +++++-
41 kex.h | 29 +++
42 kexdh.c | 10 +
43 kexgen.c | 2 +-
44 kexgssc.c | 606 ++++++++++++++++++++++++++++++++++++++++++++++++
45 kexgsss.c | 474 +++++++++++++++++++++++++++++++++++++
46 monitor.c | 139 ++++++++++-
47 monitor.h | 2 +
48 monitor_wrap.c | 57 ++++-
49 monitor_wrap.h | 4 +-
50 readconf.c | 70 ++++++
51 readconf.h | 6 +
52 servconf.c | 47 ++++
53 servconf.h | 3 +
54 session.c | 10 +-
55 ssh-gss.h | 54 ++++-
56 ssh.1 | 8 +
57 ssh.c | 6 +-
58 ssh_config | 2 +
59 ssh_config.5 | 57 +++++
60 sshconnect2.c | 154 +++++++++++-
61 sshd.c | 62 ++++-
62 sshd_config | 2 +
63 sshd_config.5 | 30 +++
64 sshkey.c | 3 +-
65 sshkey.h | 1 +
66 38 files changed, 2640 insertions(+), 160 deletions(-)
67 create mode 100644 kexgssc.c
68 create mode 100644 kexgsss.c
69
70diff --git a/Makefile.in b/Makefile.in
71index acfb919da..56759c388 100644
72--- a/Makefile.in
73+++ b/Makefile.in
74@@ -107,6 +107,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
75 kex.o kexdh.o kexgex.o kexecdh.o kexc25519.o \
76 kexgexc.o kexgexs.o \
77 sntrup4591761.o kexsntrup4591761x25519.o kexgen.o \
78+ kexgssc.o \
79 sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
80 sshbuf-io.o
81
82@@ -123,7 +124,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o \
83 auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
84 auth2-none.o auth2-passwd.o auth2-pubkey.o \
85 monitor.o monitor_wrap.o auth-krb5.o \
86- auth2-gss.o gss-serv.o gss-serv-krb5.o \
87+ auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o \
88 loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
89 sftp-server.o sftp-common.o \
90 sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
91diff --git a/README.md b/README.md
92index 28fb43d2a..5b73d24c0 100644
93--- a/README.md
94+++ b/README.md
95@@ -1,3 +1,36 @@
96+Portable OpenSSH with GSSAPI Key Exchange patches
97+=================================================
98+
99+Currently, there are two branches with gssapi key exchange related
100+patches:
101+
102+ * fedora/master: Changes that are shipped in Fedora
103+ * debian/master: Changes that are shipped in Debian
104+
105+The target is to converge to a shared repository with single master
106+branch from where we could build releases for both OSes.
107+
108+
109+What is in:
110+
111+ * The original patch implementing missing parts of RFC4462 by Simon Wilkinson
112+ adapted to the current OpenSSH versions and with several fixes
113+ * New methods for GSSAPI Kex from IETF draft [1] from Jakub Jelen
114+
115+
116+Missing kerberos-related parts:
117+
118+ * .k5login and .kusers support available in Fedora [2] [3].
119+ * Improved handling of kerberos ccache location [4]
120+
121+
122+[1] https://tools.ietf.org/html/draft-ietf-curdle-gss-keyex-sha2-08
123+[2] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-kuserok.patch
124+[3] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-GSSAPIEnablek5users.patch
125+[4] https://bugzilla.mindrot.org/show_bug.cgi?id=2775
126+
127+-------------------------------------------------------------------------------
128+
129 # Portable OpenSSH
130
131 [![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/openssh.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:openssh)
132diff --git a/auth.c b/auth.c
133index 9a5498b66..3d31ec860 100644
134--- a/auth.c
135+++ b/auth.c
136@@ -400,7 +400,8 @@ auth_root_allowed(struct ssh *ssh, const char *method)
137 case PERMIT_NO_PASSWD:
138 if (strcmp(method, "publickey") == 0 ||
139 strcmp(method, "hostbased") == 0 ||
140- strcmp(method, "gssapi-with-mic") == 0)
141+ strcmp(method, "gssapi-with-mic") == 0 ||
142+ strcmp(method, "gssapi-keyex") == 0)
143 return 1;
144 break;
145 case PERMIT_FORCED_ONLY:
146@@ -724,99 +725,6 @@ fakepw(void)
147 return (&fake);
148 }
149
150-/*
151- * Returns the remote DNS hostname as a string. The returned string must not
152- * be freed. NB. this will usually trigger a DNS query the first time it is
153- * called.
154- * This function does additional checks on the hostname to mitigate some
155- * attacks on legacy rhosts-style authentication.
156- * XXX is RhostsRSAAuthentication vulnerable to these?
157- * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
158- */
159-
160-static char *
161-remote_hostname(struct ssh *ssh)
162-{
163- struct sockaddr_storage from;
164- socklen_t fromlen;
165- struct addrinfo hints, *ai, *aitop;
166- char name[NI_MAXHOST], ntop2[NI_MAXHOST];
167- const char *ntop = ssh_remote_ipaddr(ssh);
168-
169- /* Get IP address of client. */
170- fromlen = sizeof(from);
171- memset(&from, 0, sizeof(from));
172- if (getpeername(ssh_packet_get_connection_in(ssh),
173- (struct sockaddr *)&from, &fromlen) == -1) {
174- debug("getpeername failed: %.100s", strerror(errno));
175- return xstrdup(ntop);
176- }
177-
178- ipv64_normalise_mapped(&from, &fromlen);
179- if (from.ss_family == AF_INET6)
180- fromlen = sizeof(struct sockaddr_in6);
181-
182- debug3("Trying to reverse map address %.100s.", ntop);
183- /* Map the IP address to a host name. */
184- if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
185- NULL, 0, NI_NAMEREQD) != 0) {
186- /* Host name not found. Use ip address. */
187- return xstrdup(ntop);
188- }
189-
190- /*
191- * if reverse lookup result looks like a numeric hostname,
192- * someone is trying to trick us by PTR record like following:
193- * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
194- */
195- memset(&hints, 0, sizeof(hints));
196- hints.ai_socktype = SOCK_DGRAM; /*dummy*/
197- hints.ai_flags = AI_NUMERICHOST;
198- if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
199- logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
200- name, ntop);
201- freeaddrinfo(ai);
202- return xstrdup(ntop);
203- }
204-
205- /* Names are stored in lowercase. */
206- lowercase(name);
207-
208- /*
209- * Map it back to an IP address and check that the given
210- * address actually is an address of this host. This is
211- * necessary because anyone with access to a name server can
212- * define arbitrary names for an IP address. Mapping from
213- * name to IP address can be trusted better (but can still be
214- * fooled if the intruder has access to the name server of
215- * the domain).
216- */
217- memset(&hints, 0, sizeof(hints));
218- hints.ai_family = from.ss_family;
219- hints.ai_socktype = SOCK_STREAM;
220- if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
221- logit("reverse mapping checking getaddrinfo for %.700s "
222- "[%s] failed.", name, ntop);
223- return xstrdup(ntop);
224- }
225- /* Look for the address from the list of addresses. */
226- for (ai = aitop; ai; ai = ai->ai_next) {
227- if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
228- sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
229- (strcmp(ntop, ntop2) == 0))
230- break;
231- }
232- freeaddrinfo(aitop);
233- /* If we reached the end of the list, the address was not there. */
234- if (ai == NULL) {
235- /* Address not found for the host name. */
236- logit("Address %.100s maps to %.600s, but this does not "
237- "map back to the address.", ntop, name);
238- return xstrdup(ntop);
239- }
240- return xstrdup(name);
241-}
242-
243 /*
244 * Return the canonical name of the host in the other side of the current
245 * connection. The host name is cached, so it is efficient to call this
246diff --git a/auth2-gss.c b/auth2-gss.c
247index 9351e0428..d6446c0cf 100644
248--- a/auth2-gss.c
249+++ b/auth2-gss.c
250@@ -1,7 +1,7 @@
251 /* $OpenBSD: auth2-gss.c,v 1.29 2018/07/31 03:10:27 djm Exp $ */
252
253 /*
254- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
255+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
256 *
257 * Redistribution and use in source and binary forms, with or without
258 * modification, are permitted provided that the following conditions
259@@ -54,6 +54,48 @@ static int input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh);
260 static int input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh);
261 static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
262
263+/*
264+ * The 'gssapi_keyex' userauth mechanism.
265+ */
266+static int
267+userauth_gsskeyex(struct ssh *ssh)
268+{
269+ Authctxt *authctxt = ssh->authctxt;
270+ int r, authenticated = 0;
271+ struct sshbuf *b = NULL;
272+ gss_buffer_desc mic, gssbuf;
273+ u_char *p;
274+ size_t len;
275+
276+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
277+ (r = sshpkt_get_end(ssh)) != 0)
278+ fatal("%s: %s", __func__, ssh_err(r));
279+
280+ if ((b = sshbuf_new()) == NULL)
281+ fatal("%s: sshbuf_new failed", __func__);
282+
283+ mic.value = p;
284+ mic.length = len;
285+
286+ ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
287+ "gssapi-keyex");
288+
289+ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
290+ fatal("%s: sshbuf_mutable_ptr failed", __func__);
291+ gssbuf.length = sshbuf_len(b);
292+
293+ /* gss_kex_context is NULL with privsep, so we can't check it here */
294+ if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
295+ &gssbuf, &mic))))
296+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
297+ authctxt->pw, 1));
298+
299+ sshbuf_free(b);
300+ free(mic.value);
301+
302+ return (authenticated);
303+}
304+
305 /*
306 * We only support those mechanisms that we know about (ie ones that we know
307 * how to check local user kuserok and the like)
308@@ -260,7 +302,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
309 if ((r = sshpkt_get_end(ssh)) != 0)
310 fatal("%s: %s", __func__, ssh_err(r));
311
312- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
313+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
314+ authctxt->pw, 1));
315
316 if ((!use_privsep || mm_is_monitor()) &&
317 (displayname = ssh_gssapi_displayname()) != NULL)
318@@ -306,7 +349,8 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
319 gssbuf.length = sshbuf_len(b);
320
321 if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
322- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
323+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
324+ authctxt->pw, 0));
325 else
326 logit("GSSAPI MIC check failed");
327
328@@ -326,6 +370,12 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
329 return 0;
330 }
331
332+Authmethod method_gsskeyex = {
333+ "gssapi-keyex",
334+ userauth_gsskeyex,
335+ &options.gss_authentication
336+};
337+
338 Authmethod method_gssapi = {
339 "gssapi-with-mic",
340 userauth_gssapi,
341diff --git a/auth2.c b/auth2.c
342index 242a7adbe..9fa1404b3 100644
343--- a/auth2.c
344+++ b/auth2.c
345@@ -73,6 +73,7 @@ extern Authmethod method_passwd;
346 extern Authmethod method_kbdint;
347 extern Authmethod method_hostbased;
348 #ifdef GSSAPI
349+extern Authmethod method_gsskeyex;
350 extern Authmethod method_gssapi;
351 #endif
352
353@@ -80,6 +81,7 @@ Authmethod *authmethods[] = {
354 &method_none,
355 &method_pubkey,
356 #ifdef GSSAPI
357+ &method_gsskeyex,
358 &method_gssapi,
359 #endif
360 &method_passwd,
361diff --git a/canohost.c b/canohost.c
362index abea9c6e6..8e81b5193 100644
363--- a/canohost.c
364+++ b/canohost.c
365@@ -35,6 +35,99 @@
366 #include "canohost.h"
367 #include "misc.h"
368
369+/*
370+ * Returns the remote DNS hostname as a string. The returned string must not
371+ * be freed. NB. this will usually trigger a DNS query the first time it is
372+ * called.
373+ * This function does additional checks on the hostname to mitigate some
374+ * attacks on legacy rhosts-style authentication.
375+ * XXX is RhostsRSAAuthentication vulnerable to these?
376+ * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
377+ */
378+
379+char *
380+remote_hostname(struct ssh *ssh)
381+{
382+ struct sockaddr_storage from;
383+ socklen_t fromlen;
384+ struct addrinfo hints, *ai, *aitop;
385+ char name[NI_MAXHOST], ntop2[NI_MAXHOST];
386+ const char *ntop = ssh_remote_ipaddr(ssh);
387+
388+ /* Get IP address of client. */
389+ fromlen = sizeof(from);
390+ memset(&from, 0, sizeof(from));
391+ if (getpeername(ssh_packet_get_connection_in(ssh),
392+ (struct sockaddr *)&from, &fromlen) == -1) {
393+ debug("getpeername failed: %.100s", strerror(errno));
394+ return xstrdup(ntop);
395+ }
396+
397+ ipv64_normalise_mapped(&from, &fromlen);
398+ if (from.ss_family == AF_INET6)
399+ fromlen = sizeof(struct sockaddr_in6);
400+
401+ debug3("Trying to reverse map address %.100s.", ntop);
402+ /* Map the IP address to a host name. */
403+ if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
404+ NULL, 0, NI_NAMEREQD) != 0) {
405+ /* Host name not found. Use ip address. */
406+ return xstrdup(ntop);
407+ }
408+
409+ /*
410+ * if reverse lookup result looks like a numeric hostname,
411+ * someone is trying to trick us by PTR record like following:
412+ * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
413+ */
414+ memset(&hints, 0, sizeof(hints));
415+ hints.ai_socktype = SOCK_DGRAM; /*dummy*/
416+ hints.ai_flags = AI_NUMERICHOST;
417+ if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
418+ logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
419+ name, ntop);
420+ freeaddrinfo(ai);
421+ return xstrdup(ntop);
422+ }
423+
424+ /* Names are stored in lowercase. */
425+ lowercase(name);
426+
427+ /*
428+ * Map it back to an IP address and check that the given
429+ * address actually is an address of this host. This is
430+ * necessary because anyone with access to a name server can
431+ * define arbitrary names for an IP address. Mapping from
432+ * name to IP address can be trusted better (but can still be
433+ * fooled if the intruder has access to the name server of
434+ * the domain).
435+ */
436+ memset(&hints, 0, sizeof(hints));
437+ hints.ai_family = from.ss_family;
438+ hints.ai_socktype = SOCK_STREAM;
439+ if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
440+ logit("reverse mapping checking getaddrinfo for %.700s "
441+ "[%s] failed.", name, ntop);
442+ return xstrdup(ntop);
443+ }
444+ /* Look for the address from the list of addresses. */
445+ for (ai = aitop; ai; ai = ai->ai_next) {
446+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
447+ sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
448+ (strcmp(ntop, ntop2) == 0))
449+ break;
450+ }
451+ freeaddrinfo(aitop);
452+ /* If we reached the end of the list, the address was not there. */
453+ if (ai == NULL) {
454+ /* Address not found for the host name. */
455+ logit("Address %.100s maps to %.600s, but this does not "
456+ "map back to the address.", ntop, name);
457+ return xstrdup(ntop);
458+ }
459+ return xstrdup(name);
460+}
461+
462 void
463 ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
464 {
465diff --git a/canohost.h b/canohost.h
466index 26d62855a..0cadc9f18 100644
467--- a/canohost.h
468+++ b/canohost.h
469@@ -15,6 +15,9 @@
470 #ifndef _CANOHOST_H
471 #define _CANOHOST_H
472
473+struct ssh;
474+
475+char *remote_hostname(struct ssh *);
476 char *get_peer_ipaddr(int);
477 int get_peer_port(int);
478 char *get_local_ipaddr(int);
479diff --git a/clientloop.c b/clientloop.c
480index 60b46d161..2cebea29f 100644
481--- a/clientloop.c
482+++ b/clientloop.c
483@@ -112,6 +112,10 @@
484 #include "ssherr.h"
485 #include "hostfile.h"
486
487+#ifdef GSSAPI
488+#include "ssh-gss.h"
489+#endif
490+
491 /* import options */
492 extern Options options;
493
494@@ -1368,9 +1372,18 @@ client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
495 break;
496
497 /* Do channel operations unless rekeying in progress. */
498- if (!ssh_packet_is_rekeying(ssh))
499+ if (!ssh_packet_is_rekeying(ssh)) {
500 channel_after_select(ssh, readset, writeset);
501
502+#ifdef GSSAPI
503+ if (options.gss_renewal_rekey &&
504+ ssh_gssapi_credentials_updated(NULL)) {
505+ debug("credentials updated - forcing rekey");
506+ need_rekeying = 1;
507+ }
508+#endif
509+ }
510+
511 /* Buffer input from the connection. */
512 client_process_net_input(ssh, readset);
513
514diff --git a/configure.ac b/configure.ac
515index 7005a503e..c8a96deb4 100644
516--- a/configure.ac
517+++ b/configure.ac
518@@ -679,6 +679,30 @@ main() { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16))
519 [Use tunnel device compatibility to OpenBSD])
520 AC_DEFINE([SSH_TUN_PREPEND_AF], [1],
521 [Prepend the address family to IP tunnel traffic])
522+ AC_MSG_CHECKING([if we have the Security Authorization Session API])
523+ AC_TRY_COMPILE([#include <Security/AuthSession.h>],
524+ [SessionCreate(0, 0);],
525+ [ac_cv_use_security_session_api="yes"
526+ AC_DEFINE([USE_SECURITY_SESSION_API], [1],
527+ [platform has the Security Authorization Session API])
528+ LIBS="$LIBS -framework Security"
529+ AC_MSG_RESULT([yes])],
530+ [ac_cv_use_security_session_api="no"
531+ AC_MSG_RESULT([no])])
532+ AC_MSG_CHECKING([if we have an in-memory credentials cache])
533+ AC_TRY_COMPILE(
534+ [#include <Kerberos/Kerberos.h>],
535+ [cc_context_t c;
536+ (void) cc_initialize (&c, 0, NULL, NULL);],
537+ [AC_DEFINE([USE_CCAPI], [1],
538+ [platform uses an in-memory credentials cache])
539+ LIBS="$LIBS -framework Security"
540+ AC_MSG_RESULT([yes])
541+ if test "x$ac_cv_use_security_session_api" = "xno"; then
542+ AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***])
543+ fi],
544+ [AC_MSG_RESULT([no])]
545+ )
546 m4_pattern_allow([AU_IPv])
547 AC_CHECK_DECL([AU_IPv4], [],
548 AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records])
549diff --git a/gss-genr.c b/gss-genr.c
550index d56257b4a..763a63ffa 100644
551--- a/gss-genr.c
552+++ b/gss-genr.c
553@@ -1,7 +1,7 @@
554 /* $OpenBSD: gss-genr.c,v 1.26 2018/07/10 09:13:30 djm Exp $ */
555
556 /*
557- * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
558+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
559 *
560 * Redistribution and use in source and binary forms, with or without
561 * modification, are permitted provided that the following conditions
562@@ -41,12 +41,36 @@
563 #include "sshbuf.h"
564 #include "log.h"
565 #include "ssh2.h"
566+#include "cipher.h"
567+#include "sshkey.h"
568+#include "kex.h"
569+#include "digest.h"
570+#include "packet.h"
571
572 #include "ssh-gss.h"
573
574 extern u_char *session_id2;
575 extern u_int session_id2_len;
576
577+typedef struct {
578+ char *encoded;
579+ gss_OID oid;
580+} ssh_gss_kex_mapping;
581+
582+/*
583+ * XXX - It would be nice to find a more elegant way of handling the
584+ * XXX passing of the key exchange context to the userauth routines
585+ */
586+
587+Gssctxt *gss_kex_context = NULL;
588+
589+static ssh_gss_kex_mapping *gss_enc2oid = NULL;
590+
591+int
592+ssh_gssapi_oid_table_ok(void) {
593+ return (gss_enc2oid != NULL);
594+}
595+
596 /* sshbuf_get for gss_buffer_desc */
597 int
598 ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
599@@ -62,6 +86,162 @@ ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
600 return 0;
601 }
602
603+/* sshpkt_get of gss_buffer_desc */
604+int
605+ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *ssh, gss_buffer_desc *g)
606+{
607+ int r;
608+ u_char *p;
609+ size_t len;
610+
611+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0)
612+ return r;
613+ g->value = p;
614+ g->length = len;
615+ return 0;
616+}
617+
618+/*
619+ * Return a list of the gss-group1-sha1 mechanisms supported by this program
620+ *
621+ * We test mechanisms to ensure that we can use them, to avoid starting
622+ * a key exchange with a bad mechanism
623+ */
624+
625+char *
626+ssh_gssapi_client_mechanisms(const char *host, const char *client,
627+ const char *kex) {
628+ gss_OID_set gss_supported = NULL;
629+ OM_uint32 min_status;
630+
631+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
632+ return NULL;
633+
634+ return ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
635+ host, client, kex);
636+}
637+
638+char *
639+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
640+ const char *host, const char *client, const char *kex) {
641+ struct sshbuf *buf = NULL;
642+ size_t i;
643+ int r = SSH_ERR_ALLOC_FAIL;
644+ int oidpos, enclen;
645+ char *mechs, *encoded;
646+ u_char digest[SSH_DIGEST_MAX_LENGTH];
647+ char deroid[2];
648+ struct ssh_digest_ctx *md = NULL;
649+ char *s, *cp, *p;
650+
651+ if (gss_enc2oid != NULL) {
652+ for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
653+ free(gss_enc2oid[i].encoded);
654+ free(gss_enc2oid);
655+ }
656+
657+ gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
658+ (gss_supported->count + 1));
659+
660+ if ((buf = sshbuf_new()) == NULL)
661+ fatal("%s: sshbuf_new failed", __func__);
662+
663+ oidpos = 0;
664+ s = cp = xstrdup(kex);
665+ for (i = 0; i < gss_supported->count; i++) {
666+ if (gss_supported->elements[i].length < 128 &&
667+ (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
668+
669+ deroid[0] = SSH_GSS_OIDTYPE;
670+ deroid[1] = gss_supported->elements[i].length;
671+
672+ if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
673+ (r = ssh_digest_update(md, deroid, 2)) != 0 ||
674+ (r = ssh_digest_update(md,
675+ gss_supported->elements[i].elements,
676+ gss_supported->elements[i].length)) != 0 ||
677+ (r = ssh_digest_final(md, digest, sizeof(digest))) != 0)
678+ fatal("%s: digest failed: %s", __func__,
679+ ssh_err(r));
680+ ssh_digest_free(md);
681+ md = NULL;
682+
683+ encoded = xmalloc(ssh_digest_bytes(SSH_DIGEST_MD5)
684+ * 2);
685+ enclen = __b64_ntop(digest,
686+ ssh_digest_bytes(SSH_DIGEST_MD5), encoded,
687+ ssh_digest_bytes(SSH_DIGEST_MD5) * 2);
688+
689+ cp = strncpy(s, kex, strlen(kex));
690+ for ((p = strsep(&cp, ",")); p && *p != '\0';
691+ (p = strsep(&cp, ","))) {
692+ if (sshbuf_len(buf) != 0 &&
693+ (r = sshbuf_put_u8(buf, ',')) != 0)
694+ fatal("%s: sshbuf_put_u8 error: %s",
695+ __func__, ssh_err(r));
696+ if ((r = sshbuf_put(buf, p, strlen(p))) != 0 ||
697+ (r = sshbuf_put(buf, encoded, enclen)) != 0)
698+ fatal("%s: sshbuf_put error: %s",
699+ __func__, ssh_err(r));
700+ }
701+
702+ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
703+ gss_enc2oid[oidpos].encoded = encoded;
704+ oidpos++;
705+ }
706+ }
707+ free(s);
708+ gss_enc2oid[oidpos].oid = NULL;
709+ gss_enc2oid[oidpos].encoded = NULL;
710+
711+ if ((mechs = sshbuf_dup_string(buf)) == NULL)
712+ fatal("%s: sshbuf_dup_string failed", __func__);
713+
714+ sshbuf_free(buf);
715+
716+ if (strlen(mechs) == 0) {
717+ free(mechs);
718+ mechs = NULL;
719+ }
720+
721+ return (mechs);
722+}
723+
724+gss_OID
725+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
726+ int i = 0;
727+
728+#define SKIP_KEX_NAME(type) \
729+ case type: \
730+ if (strlen(name) < sizeof(type##_ID)) \
731+ return GSS_C_NO_OID; \
732+ name += sizeof(type##_ID) - 1; \
733+ break;
734+
735+ switch (kex_type) {
736+ SKIP_KEX_NAME(KEX_GSS_GRP1_SHA1)
737+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA1)
738+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA256)
739+ SKIP_KEX_NAME(KEX_GSS_GRP16_SHA512)
740+ SKIP_KEX_NAME(KEX_GSS_GEX_SHA1)
741+ SKIP_KEX_NAME(KEX_GSS_NISTP256_SHA256)
742+ SKIP_KEX_NAME(KEX_GSS_C25519_SHA256)
743+ default:
744+ return GSS_C_NO_OID;
745+ }
746+
747+#undef SKIP_KEX_NAME
748+
749+ while (gss_enc2oid[i].encoded != NULL &&
750+ strcmp(name, gss_enc2oid[i].encoded) != 0)
751+ i++;
752+
753+ if (gss_enc2oid[i].oid != NULL && ctx != NULL)
754+ ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
755+
756+ return gss_enc2oid[i].oid;
757+}
758+
759 /* Check that the OID in a data stream matches that in the context */
760 int
761 ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
762@@ -218,7 +398,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
763 }
764
765 ctx->major = gss_init_sec_context(&ctx->minor,
766- GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
767+ ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
768 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
769 0, NULL, recv_tok, NULL, send_tok, flags, NULL);
770
771@@ -247,9 +427,43 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
772 return (ctx->major);
773 }
774
775+OM_uint32
776+ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
777+{
778+ gss_buffer_desc gssbuf;
779+ gss_name_t gssname;
780+ OM_uint32 status;
781+ gss_OID_set oidset;
782+
783+ gssbuf.value = (void *) name;
784+ gssbuf.length = strlen(gssbuf.value);
785+
786+ gss_create_empty_oid_set(&status, &oidset);
787+ gss_add_oid_set_member(&status, ctx->oid, &oidset);
788+
789+ ctx->major = gss_import_name(&ctx->minor, &gssbuf,
790+ GSS_C_NT_USER_NAME, &gssname);
791+
792+ if (!ctx->major)
793+ ctx->major = gss_acquire_cred(&ctx->minor,
794+ gssname, 0, oidset, GSS_C_INITIATE,
795+ &ctx->client_creds, NULL, NULL);
796+
797+ gss_release_name(&status, &gssname);
798+ gss_release_oid_set(&status, &oidset);
799+
800+ if (ctx->major)
801+ ssh_gssapi_error(ctx);
802+
803+ return(ctx->major);
804+}
805+
806 OM_uint32
807 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
808 {
809+ if (ctx == NULL)
810+ return -1;
811+
812 if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
813 GSS_C_QOP_DEFAULT, buffer, hash)))
814 ssh_gssapi_error(ctx);
815@@ -257,6 +471,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
816 return (ctx->major);
817 }
818
819+/* Priviledged when used by server */
820+OM_uint32
821+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
822+{
823+ if (ctx == NULL)
824+ return -1;
825+
826+ ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
827+ gssbuf, gssmic, NULL);
828+
829+ return (ctx->major);
830+}
831+
832 void
833 ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
834 const char *context)
835@@ -273,11 +500,16 @@ ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
836 }
837
838 int
839-ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
840+ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
841+ const char *client)
842 {
843 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
844 OM_uint32 major, minor;
845 gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
846+ Gssctxt *intctx = NULL;
847+
848+ if (ctx == NULL)
849+ ctx = &intctx;
850
851 /* RFC 4462 says we MUST NOT do SPNEGO */
852 if (oid->length == spnego_oid.length &&
853@@ -287,6 +519,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
854 ssh_gssapi_build_ctx(ctx);
855 ssh_gssapi_set_oid(*ctx, oid);
856 major = ssh_gssapi_import_name(*ctx, host);
857+
858+ if (!GSS_ERROR(major) && client)
859+ major = ssh_gssapi_client_identity(*ctx, client);
860+
861 if (!GSS_ERROR(major)) {
862 major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
863 NULL);
864@@ -296,10 +532,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
865 GSS_C_NO_BUFFER);
866 }
867
868- if (GSS_ERROR(major))
869+ if (GSS_ERROR(major) || intctx != NULL)
870 ssh_gssapi_delete_ctx(ctx);
871
872 return (!GSS_ERROR(major));
873 }
874
875+int
876+ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
877+ static gss_name_t saved_name = GSS_C_NO_NAME;
878+ static OM_uint32 saved_lifetime = 0;
879+ static gss_OID saved_mech = GSS_C_NO_OID;
880+ static gss_name_t name;
881+ static OM_uint32 last_call = 0;
882+ OM_uint32 lifetime, now, major, minor;
883+ int equal;
884+
885+ now = time(NULL);
886+
887+ if (ctxt) {
888+ debug("Rekey has happened - updating saved versions");
889+
890+ if (saved_name != GSS_C_NO_NAME)
891+ gss_release_name(&minor, &saved_name);
892+
893+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
894+ &saved_name, &saved_lifetime, NULL, NULL);
895+
896+ if (!GSS_ERROR(major)) {
897+ saved_mech = ctxt->oid;
898+ saved_lifetime+= now;
899+ } else {
900+ /* Handle the error */
901+ }
902+ return 0;
903+ }
904+
905+ if (now - last_call < 10)
906+ return 0;
907+
908+ last_call = now;
909+
910+ if (saved_mech == GSS_C_NO_OID)
911+ return 0;
912+
913+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
914+ &name, &lifetime, NULL, NULL);
915+ if (major == GSS_S_CREDENTIALS_EXPIRED)
916+ return 0;
917+ else if (GSS_ERROR(major))
918+ return 0;
919+
920+ major = gss_compare_name(&minor, saved_name, name, &equal);
921+ gss_release_name(&minor, &name);
922+ if (GSS_ERROR(major))
923+ return 0;
924+
925+ if (equal && (saved_lifetime < lifetime + now - 10))
926+ return 1;
927+
928+ return 0;
929+}
930+
931 #endif /* GSSAPI */
932diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c
933index a151bc1e4..ef9beb67c 100644
934--- a/gss-serv-krb5.c
935+++ b/gss-serv-krb5.c
936@@ -1,7 +1,7 @@
937 /* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */
938
939 /*
940- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
941+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
942 *
943 * Redistribution and use in source and binary forms, with or without
944 * modification, are permitted provided that the following conditions
945@@ -120,8 +120,8 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
946 krb5_error_code problem;
947 krb5_principal princ;
948 OM_uint32 maj_status, min_status;
949- int len;
950 const char *errmsg;
951+ const char *new_ccname;
952
953 if (client->creds == NULL) {
954 debug("No credentials stored");
955@@ -180,11 +180,16 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
956 return;
957 }
958
959- client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
960+ new_ccname = krb5_cc_get_name(krb_context, ccache);
961+
962 client->store.envvar = "KRB5CCNAME";
963- len = strlen(client->store.filename) + 6;
964- client->store.envval = xmalloc(len);
965- snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
966+#ifdef USE_CCAPI
967+ xasprintf(&client->store.envval, "API:%s", new_ccname);
968+ client->store.filename = NULL;
969+#else
970+ xasprintf(&client->store.envval, "FILE:%s", new_ccname);
971+ client->store.filename = xstrdup(new_ccname);
972+#endif
973
974 #ifdef USE_PAM
975 if (options.use_pam)
976@@ -196,6 +201,71 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
977 return;
978 }
979
980+int
981+ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store,
982+ ssh_gssapi_client *client)
983+{
984+ krb5_ccache ccache = NULL;
985+ krb5_principal principal = NULL;
986+ char *name = NULL;
987+ krb5_error_code problem;
988+ OM_uint32 maj_status, min_status;
989+
990+ if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
991+ logit("krb5_cc_resolve(): %.100s",
992+ krb5_get_err_text(krb_context, problem));
993+ return 0;
994+ }
995+
996+ /* Find out who the principal in this cache is */
997+ if ((problem = krb5_cc_get_principal(krb_context, ccache,
998+ &principal))) {
999+ logit("krb5_cc_get_principal(): %.100s",
1000+ krb5_get_err_text(krb_context, problem));
1001+ krb5_cc_close(krb_context, ccache);
1002+ return 0;
1003+ }
1004+
1005+ if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
1006+ logit("krb5_unparse_name(): %.100s",
1007+ krb5_get_err_text(krb_context, problem));
1008+ krb5_free_principal(krb_context, principal);
1009+ krb5_cc_close(krb_context, ccache);
1010+ return 0;
1011+ }
1012+
1013+
1014+ if (strcmp(name,client->exportedname.value)!=0) {
1015+ debug("Name in local credentials cache differs. Not storing");
1016+ krb5_free_principal(krb_context, principal);
1017+ krb5_cc_close(krb_context, ccache);
1018+ krb5_free_unparsed_name(krb_context, name);
1019+ return 0;
1020+ }
1021+ krb5_free_unparsed_name(krb_context, name);
1022+
1023+ /* Name matches, so lets get on with it! */
1024+
1025+ if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
1026+ logit("krb5_cc_initialize(): %.100s",
1027+ krb5_get_err_text(krb_context, problem));
1028+ krb5_free_principal(krb_context, principal);
1029+ krb5_cc_close(krb_context, ccache);
1030+ return 0;
1031+ }
1032+
1033+ krb5_free_principal(krb_context, principal);
1034+
1035+ if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
1036+ ccache))) {
1037+ logit("gss_krb5_copy_ccache() failed. Sorry!");
1038+ krb5_cc_close(krb_context, ccache);
1039+ return 0;
1040+ }
1041+
1042+ return 1;
1043+}
1044+
1045 ssh_gssapi_mech gssapi_kerberos_mech = {
1046 "toWM5Slw5Ew8Mqkay+al2g==",
1047 "Kerberos",
1048@@ -203,7 +273,8 @@ ssh_gssapi_mech gssapi_kerberos_mech = {
1049 NULL,
1050 &ssh_gssapi_krb5_userok,
1051 NULL,
1052- &ssh_gssapi_krb5_storecreds
1053+ &ssh_gssapi_krb5_storecreds,
1054+ &ssh_gssapi_krb5_updatecreds
1055 };
1056
1057 #endif /* KRB5 */
1058diff --git a/gss-serv.c b/gss-serv.c
1059index b5d4bb2d1..55f4d4bda 100644
1060--- a/gss-serv.c
1061+++ b/gss-serv.c
1062@@ -1,7 +1,7 @@
1063 /* $OpenBSD: gss-serv.c,v 1.32 2020/03/13 03:17:07 djm Exp $ */
1064
1065 /*
1066- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
1067+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
1068 *
1069 * Redistribution and use in source and binary forms, with or without
1070 * modification, are permitted provided that the following conditions
1071@@ -44,17 +44,19 @@
1072 #include "session.h"
1073 #include "misc.h"
1074 #include "servconf.h"
1075+#include "uidswap.h"
1076
1077 #include "ssh-gss.h"
1078+#include "monitor_wrap.h"
1079
1080 extern ServerOptions options;
1081
1082 static ssh_gssapi_client gssapi_client =
1083- { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
1084- GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL, NULL}};
1085+ { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER, GSS_C_NO_CREDENTIAL,
1086+ GSS_C_NO_NAME, NULL, {NULL, NULL, NULL, NULL, NULL}, 0, 0};
1087
1088 ssh_gssapi_mech gssapi_null_mech =
1089- { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
1090+ { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL};
1091
1092 #ifdef KRB5
1093 extern ssh_gssapi_mech gssapi_kerberos_mech;
1094@@ -140,6 +142,29 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid)
1095 return (ssh_gssapi_acquire_cred(*ctx));
1096 }
1097
1098+/* Unprivileged */
1099+char *
1100+ssh_gssapi_server_mechanisms(void) {
1101+ if (supported_oids == NULL)
1102+ ssh_gssapi_prepare_supported_oids();
1103+ return (ssh_gssapi_kex_mechs(supported_oids,
1104+ &ssh_gssapi_server_check_mech, NULL, NULL,
1105+ options.gss_kex_algorithms));
1106+}
1107+
1108+/* Unprivileged */
1109+int
1110+ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data,
1111+ const char *dummy) {
1112+ Gssctxt *ctx = NULL;
1113+ int res;
1114+
1115+ res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid)));
1116+ ssh_gssapi_delete_ctx(&ctx);
1117+
1118+ return (res);
1119+}
1120+
1121 /* Unprivileged */
1122 void
1123 ssh_gssapi_supported_oids(gss_OID_set *oidset)
1124@@ -150,7 +175,9 @@ ssh_gssapi_supported_oids(gss_OID_set *oidset)
1125 gss_OID_set supported;
1126
1127 gss_create_empty_oid_set(&min_status, oidset);
1128- gss_indicate_mechs(&min_status, &supported);
1129+
1130+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &supported)))
1131+ return;
1132
1133 while (supported_mechs[i]->name != NULL) {
1134 if (GSS_ERROR(gss_test_oid_set_member(&min_status,
1135@@ -276,8 +303,48 @@ OM_uint32
1136 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
1137 {
1138 int i = 0;
1139+ int equal = 0;
1140+ gss_name_t new_name = GSS_C_NO_NAME;
1141+ gss_buffer_desc ename = GSS_C_EMPTY_BUFFER;
1142+
1143+ if (options.gss_store_rekey && client->used && ctx->client_creds) {
1144+ if (client->mech->oid.length != ctx->oid->length ||
1145+ (memcmp(client->mech->oid.elements,
1146+ ctx->oid->elements, ctx->oid->length) !=0)) {
1147+ debug("Rekeyed credentials have different mechanism");
1148+ return GSS_S_COMPLETE;
1149+ }
1150+
1151+ if ((ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
1152+ ctx->client_creds, ctx->oid, &new_name,
1153+ NULL, NULL, NULL))) {
1154+ ssh_gssapi_error(ctx);
1155+ return (ctx->major);
1156+ }
1157+
1158+ ctx->major = gss_compare_name(&ctx->minor, client->name,
1159+ new_name, &equal);
1160+
1161+ if (GSS_ERROR(ctx->major)) {
1162+ ssh_gssapi_error(ctx);
1163+ return (ctx->major);
1164+ }
1165+
1166+ if (!equal) {
1167+ debug("Rekeyed credentials have different name");
1168+ return GSS_S_COMPLETE;
1169+ }
1170
1171- gss_buffer_desc ename;
1172+ debug("Marking rekeyed credentials for export");
1173+
1174+ gss_release_name(&ctx->minor, &client->name);
1175+ gss_release_cred(&ctx->minor, &client->creds);
1176+ client->name = new_name;
1177+ client->creds = ctx->client_creds;
1178+ ctx->client_creds = GSS_C_NO_CREDENTIAL;
1179+ client->updated = 1;
1180+ return GSS_S_COMPLETE;
1181+ }
1182
1183 client->mech = NULL;
1184
1185@@ -292,6 +359,13 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
1186 if (client->mech == NULL)
1187 return GSS_S_FAILURE;
1188
1189+ if (ctx->client_creds &&
1190+ (ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
1191+ ctx->client_creds, ctx->oid, &client->name, NULL, NULL, NULL))) {
1192+ ssh_gssapi_error(ctx);
1193+ return (ctx->major);
1194+ }
1195+
1196 if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
1197 &client->displayname, NULL))) {
1198 ssh_gssapi_error(ctx);
1199@@ -309,6 +383,8 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
1200 return (ctx->major);
1201 }
1202
1203+ gss_release_buffer(&ctx->minor, &ename);
1204+
1205 /* We can't copy this structure, so we just move the pointer to it */
1206 client->creds = ctx->client_creds;
1207 ctx->client_creds = GSS_C_NO_CREDENTIAL;
1208@@ -356,19 +432,23 @@ ssh_gssapi_do_child(char ***envp, u_int *envsizep)
1209
1210 /* Privileged */
1211 int
1212-ssh_gssapi_userok(char *user)
1213+ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
1214 {
1215 OM_uint32 lmin;
1216
1217+ (void) kex; /* used in privilege separation */
1218+
1219 if (gssapi_client.exportedname.length == 0 ||
1220 gssapi_client.exportedname.value == NULL) {
1221 debug("No suitable client data");
1222 return 0;
1223 }
1224 if (gssapi_client.mech && gssapi_client.mech->userok)
1225- if ((*gssapi_client.mech->userok)(&gssapi_client, user))
1226+ if ((*gssapi_client.mech->userok)(&gssapi_client, user)) {
1227+ gssapi_client.used = 1;
1228+ gssapi_client.store.owner = pw;
1229 return 1;
1230- else {
1231+ } else {
1232 /* Destroy delegated credentials if userok fails */
1233 gss_release_buffer(&lmin, &gssapi_client.displayname);
1234 gss_release_buffer(&lmin, &gssapi_client.exportedname);
1235@@ -382,14 +462,90 @@ ssh_gssapi_userok(char *user)
1236 return (0);
1237 }
1238
1239-/* Privileged */
1240-OM_uint32
1241-ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
1242+/* These bits are only used for rekeying. The unpriviledged child is running
1243+ * as the user, the monitor is root.
1244+ *
1245+ * In the child, we want to :
1246+ * *) Ask the monitor to store our credentials into the store we specify
1247+ * *) If it succeeds, maybe do a PAM update
1248+ */
1249+
1250+/* Stuff for PAM */
1251+
1252+#ifdef USE_PAM
1253+static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg,
1254+ struct pam_response **resp, void *data)
1255 {
1256- ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
1257- gssbuf, gssmic, NULL);
1258+ return (PAM_CONV_ERR);
1259+}
1260+#endif
1261
1262- return (ctx->major);
1263+void
1264+ssh_gssapi_rekey_creds(void) {
1265+ int ok;
1266+#ifdef USE_PAM
1267+ int ret;
1268+ pam_handle_t *pamh = NULL;
1269+ struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
1270+ char *envstr;
1271+#endif
1272+
1273+ if (gssapi_client.store.filename == NULL &&
1274+ gssapi_client.store.envval == NULL &&
1275+ gssapi_client.store.envvar == NULL)
1276+ return;
1277+
1278+ ok = PRIVSEP(ssh_gssapi_update_creds(&gssapi_client.store));
1279+
1280+ if (!ok)
1281+ return;
1282+
1283+ debug("Rekeyed credentials stored successfully");
1284+
1285+ /* Actually managing to play with the ssh pam stack from here will
1286+ * be next to impossible. In any case, we may want different options
1287+ * for rekeying. So, use our own :)
1288+ */
1289+#ifdef USE_PAM
1290+ if (!use_privsep) {
1291+ debug("Not even going to try and do PAM with privsep disabled");
1292+ return;
1293+ }
1294+
1295+ ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name,
1296+ &pamconv, &pamh);
1297+ if (ret)
1298+ return;
1299+
1300+ xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar,
1301+ gssapi_client.store.envval);
1302+
1303+ ret = pam_putenv(pamh, envstr);
1304+ if (!ret)
1305+ pam_setcred(pamh, PAM_REINITIALIZE_CRED);
1306+ pam_end(pamh, PAM_SUCCESS);
1307+#endif
1308+}
1309+
1310+int
1311+ssh_gssapi_update_creds(ssh_gssapi_ccache *store) {
1312+ int ok = 0;
1313+
1314+ /* Check we've got credentials to store */
1315+ if (!gssapi_client.updated)
1316+ return 0;
1317+
1318+ gssapi_client.updated = 0;
1319+
1320+ temporarily_use_uid(gssapi_client.store.owner);
1321+ if (gssapi_client.mech && gssapi_client.mech->updatecreds)
1322+ ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client);
1323+ else
1324+ debug("No update function for this mechanism");
1325+
1326+ restore_uid();
1327+
1328+ return ok;
1329 }
1330
1331 /* Privileged */
1332diff --git a/kex.c b/kex.c
1333index aecb9394d..751cfc710 100644
1334--- a/kex.c
1335+++ b/kex.c
1336@@ -57,11 +57,16 @@
1337 #include "misc.h"
1338 #include "dispatch.h"
1339 #include "monitor.h"
1340+#include "xmalloc.h"
1341
1342 #include "ssherr.h"
1343 #include "sshbuf.h"
1344 #include "digest.h"
1345
1346+#ifdef GSSAPI
1347+#include "ssh-gss.h"
1348+#endif
1349+
1350 /* prototype */
1351 static int kex_choose_conf(struct ssh *);
1352 static int kex_input_newkeys(int, u_int32_t, struct ssh *);
1353@@ -115,15 +120,28 @@ static const struct kexalg kexalgs[] = {
1354 #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
1355 { NULL, 0, -1, -1},
1356 };
1357+static const struct kexalg gss_kexalgs[] = {
1358+#ifdef GSSAPI
1359+ { KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
1360+ { KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
1361+ { KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
1362+ { KEX_GSS_GRP14_SHA256_ID, KEX_GSS_GRP14_SHA256, 0, SSH_DIGEST_SHA256 },
1363+ { KEX_GSS_GRP16_SHA512_ID, KEX_GSS_GRP16_SHA512, 0, SSH_DIGEST_SHA512 },
1364+ { KEX_GSS_NISTP256_SHA256_ID, KEX_GSS_NISTP256_SHA256,
1365+ NID_X9_62_prime256v1, SSH_DIGEST_SHA256 },
1366+ { KEX_GSS_C25519_SHA256_ID, KEX_GSS_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
1367+#endif
1368+ { NULL, 0, -1, -1},
1369+};
1370
1371-char *
1372-kex_alg_list(char sep)
1373+static char *
1374+kex_alg_list_internal(char sep, const struct kexalg *algs)
1375 {
1376 char *ret = NULL, *tmp;
1377 size_t nlen, rlen = 0;
1378 const struct kexalg *k;
1379
1380- for (k = kexalgs; k->name != NULL; k++) {
1381+ for (k = algs; k->name != NULL; k++) {
1382 if (ret != NULL)
1383 ret[rlen++] = sep;
1384 nlen = strlen(k->name);
1385@@ -138,6 +156,18 @@ kex_alg_list(char sep)
1386 return ret;
1387 }
1388
1389+char *
1390+kex_alg_list(char sep)
1391+{
1392+ return kex_alg_list_internal(sep, kexalgs);
1393+}
1394+
1395+char *
1396+kex_gss_alg_list(char sep)
1397+{
1398+ return kex_alg_list_internal(sep, gss_kexalgs);
1399+}
1400+
1401 static const struct kexalg *
1402 kex_alg_by_name(const char *name)
1403 {
1404@@ -147,6 +177,10 @@ kex_alg_by_name(const char *name)
1405 if (strcmp(k->name, name) == 0)
1406 return k;
1407 }
1408+ for (k = gss_kexalgs; k->name != NULL; k++) {
1409+ if (strncmp(k->name, name, strlen(k->name)) == 0)
1410+ return k;
1411+ }
1412 return NULL;
1413 }
1414
1415@@ -315,6 +349,29 @@ kex_assemble_names(char **listp, const char *def, const char *all)
1416 return r;
1417 }
1418
1419+/* Validate GSS KEX method name list */
1420+int
1421+kex_gss_names_valid(const char *names)
1422+{
1423+ char *s, *cp, *p;
1424+
1425+ if (names == NULL || *names == '\0')
1426+ return 0;
1427+ s = cp = xstrdup(names);
1428+ for ((p = strsep(&cp, ",")); p && *p != '\0';
1429+ (p = strsep(&cp, ","))) {
1430+ if (strncmp(p, "gss-", 4) != 0
1431+ || kex_alg_by_name(p) == NULL) {
1432+ error("Unsupported KEX algorithm \"%.100s\"", p);
1433+ free(s);
1434+ return 0;
1435+ }
1436+ }
1437+ debug3("gss kex names ok: [%s]", names);
1438+ free(s);
1439+ return 1;
1440+}
1441+
1442 /* put algorithm proposal into buffer */
1443 int
1444 kex_prop2buf(struct sshbuf *b, char *proposal[PROPOSAL_MAX])
1445@@ -697,6 +754,9 @@ kex_free(struct kex *kex)
1446 sshbuf_free(kex->server_version);
1447 sshbuf_free(kex->client_pub);
1448 free(kex->session_id);
1449+#ifdef GSSAPI
1450+ free(kex->gss_host);
1451+#endif /* GSSAPI */
1452 free(kex->failed_choice);
1453 free(kex->hostkey_alg);
1454 free(kex->name);
1455diff --git a/kex.h b/kex.h
1456index a5ae6ac05..fe7141414 100644
1457--- a/kex.h
1458+++ b/kex.h
1459@@ -102,6 +102,15 @@ enum kex_exchange {
1460 KEX_ECDH_SHA2,
1461 KEX_C25519_SHA256,
1462 KEX_KEM_SNTRUP4591761X25519_SHA512,
1463+#ifdef GSSAPI
1464+ KEX_GSS_GRP1_SHA1,
1465+ KEX_GSS_GRP14_SHA1,
1466+ KEX_GSS_GRP14_SHA256,
1467+ KEX_GSS_GRP16_SHA512,
1468+ KEX_GSS_GEX_SHA1,
1469+ KEX_GSS_NISTP256_SHA256,
1470+ KEX_GSS_C25519_SHA256,
1471+#endif
1472 KEX_MAX
1473 };
1474
1475@@ -153,6 +162,12 @@ struct kex {
1476 u_int flags;
1477 int hash_alg;
1478 int ec_nid;
1479+#ifdef GSSAPI
1480+ int gss_deleg_creds;
1481+ int gss_trust_dns;
1482+ char *gss_host;
1483+ char *gss_client;
1484+#endif
1485 char *failed_choice;
1486 int (*verify_host_key)(struct sshkey *, struct ssh *);
1487 struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
1488@@ -174,8 +189,10 @@ struct kex {
1489
1490 int kex_names_valid(const char *);
1491 char *kex_alg_list(char);
1492+char *kex_gss_alg_list(char);
1493 char *kex_names_cat(const char *, const char *);
1494 int kex_assemble_names(char **, const char *, const char *);
1495+int kex_gss_names_valid(const char *);
1496
1497 int kex_exchange_identification(struct ssh *, int, const char *);
1498
1499@@ -202,6 +219,12 @@ int kexgex_client(struct ssh *);
1500 int kexgex_server(struct ssh *);
1501 int kex_gen_client(struct ssh *);
1502 int kex_gen_server(struct ssh *);
1503+#if defined(GSSAPI) && defined(WITH_OPENSSL)
1504+int kexgssgex_client(struct ssh *);
1505+int kexgssgex_server(struct ssh *);
1506+int kexgss_client(struct ssh *);
1507+int kexgss_server(struct ssh *);
1508+#endif
1509
1510 int kex_dh_keypair(struct kex *);
1511 int kex_dh_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
1512@@ -234,6 +257,12 @@ int kexgex_hash(int, const struct sshbuf *, const struct sshbuf *,
1513 const BIGNUM *, const u_char *, size_t,
1514 u_char *, size_t *);
1515
1516+int kex_gen_hash(int hash_alg, const struct sshbuf *client_version,
1517+ const struct sshbuf *server_version, const struct sshbuf *client_kexinit,
1518+ const struct sshbuf *server_kexinit, const struct sshbuf *server_host_key_blob,
1519+ const struct sshbuf *client_pub, const struct sshbuf *server_pub,
1520+ const struct sshbuf *shared_secret, u_char *hash, size_t *hashlen);
1521+
1522 void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
1523 __attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
1524 __attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
1525diff --git a/kexdh.c b/kexdh.c
1526index 6e0159f9f..d024a8b9a 100644
1527--- a/kexdh.c
1528+++ b/kexdh.c
1529@@ -49,13 +49,23 @@ kex_dh_keygen(struct kex *kex)
1530 {
1531 switch (kex->kex_type) {
1532 case KEX_DH_GRP1_SHA1:
1533+#ifdef GSSAPI
1534+ case KEX_GSS_GRP1_SHA1:
1535+#endif
1536 kex->dh = dh_new_group1();
1537 break;
1538 case KEX_DH_GRP14_SHA1:
1539 case KEX_DH_GRP14_SHA256:
1540+#ifdef GSSAPI
1541+ case KEX_GSS_GRP14_SHA1:
1542+ case KEX_GSS_GRP14_SHA256:
1543+#endif
1544 kex->dh = dh_new_group14();
1545 break;
1546 case KEX_DH_GRP16_SHA512:
1547+#ifdef GSSAPI
1548+ case KEX_GSS_GRP16_SHA512:
1549+#endif
1550 kex->dh = dh_new_group16();
1551 break;
1552 case KEX_DH_GRP18_SHA512:
1553diff --git a/kexgen.c b/kexgen.c
1554index 69348b964..c0e8c2f44 100644
1555--- a/kexgen.c
1556+++ b/kexgen.c
1557@@ -44,7 +44,7 @@
1558 static int input_kex_gen_init(int, u_int32_t, struct ssh *);
1559 static int input_kex_gen_reply(int type, u_int32_t seq, struct ssh *ssh);
1560
1561-static int
1562+int
1563 kex_gen_hash(
1564 int hash_alg,
1565 const struct sshbuf *client_version,
1566diff --git a/kexgssc.c b/kexgssc.c
1567new file mode 100644
1568index 000000000..f6e1405eb
1569--- /dev/null
1570+++ b/kexgssc.c
1571@@ -0,0 +1,606 @@
1572+/*
1573+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
1574+ *
1575+ * Redistribution and use in source and binary forms, with or without
1576+ * modification, are permitted provided that the following conditions
1577+ * are met:
1578+ * 1. Redistributions of source code must retain the above copyright
1579+ * notice, this list of conditions and the following disclaimer.
1580+ * 2. Redistributions in binary form must reproduce the above copyright
1581+ * notice, this list of conditions and the following disclaimer in the
1582+ * documentation and/or other materials provided with the distribution.
1583+ *
1584+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
1585+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1586+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1587+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1588+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1589+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1590+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1591+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1592+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1593+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1594+ */
1595+
1596+#include "includes.h"
1597+
1598+#if defined(GSSAPI) && defined(WITH_OPENSSL)
1599+
1600+#include "includes.h"
1601+
1602+#include <openssl/crypto.h>
1603+#include <openssl/bn.h>
1604+
1605+#include <string.h>
1606+
1607+#include "xmalloc.h"
1608+#include "sshbuf.h"
1609+#include "ssh2.h"
1610+#include "sshkey.h"
1611+#include "cipher.h"
1612+#include "kex.h"
1613+#include "log.h"
1614+#include "packet.h"
1615+#include "dh.h"
1616+#include "digest.h"
1617+#include "ssherr.h"
1618+
1619+#include "ssh-gss.h"
1620+
1621+int
1622+kexgss_client(struct ssh *ssh)
1623+{
1624+ struct kex *kex = ssh->kex;
1625+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER,
1626+ recv_tok = GSS_C_EMPTY_BUFFER,
1627+ gssbuf, msg_tok = GSS_C_EMPTY_BUFFER, *token_ptr;
1628+ Gssctxt *ctxt;
1629+ OM_uint32 maj_status, min_status, ret_flags;
1630+ struct sshbuf *server_blob = NULL;
1631+ struct sshbuf *shared_secret = NULL;
1632+ struct sshbuf *server_host_key_blob = NULL;
1633+ struct sshbuf *empty = NULL;
1634+ u_char *msg;
1635+ int type = 0;
1636+ int first = 1;
1637+ u_char hash[SSH_DIGEST_MAX_LENGTH];
1638+ size_t hashlen;
1639+ u_char c;
1640+ int r;
1641+
1642+ /* Initialise our GSSAPI world */
1643+ ssh_gssapi_build_ctx(&ctxt);
1644+ if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
1645+ == GSS_C_NO_OID)
1646+ fatal("Couldn't identify host exchange");
1647+
1648+ if (ssh_gssapi_import_name(ctxt, kex->gss_host))
1649+ fatal("Couldn't import hostname");
1650+
1651+ if (kex->gss_client &&
1652+ ssh_gssapi_client_identity(ctxt, kex->gss_client))
1653+ fatal("Couldn't acquire client credentials");
1654+
1655+ /* Step 1 */
1656+ switch (kex->kex_type) {
1657+ case KEX_GSS_GRP1_SHA1:
1658+ case KEX_GSS_GRP14_SHA1:
1659+ case KEX_GSS_GRP14_SHA256:
1660+ case KEX_GSS_GRP16_SHA512:
1661+ r = kex_dh_keypair(kex);
1662+ break;
1663+ case KEX_GSS_NISTP256_SHA256:
1664+ r = kex_ecdh_keypair(kex);
1665+ break;
1666+ case KEX_GSS_C25519_SHA256:
1667+ r = kex_c25519_keypair(kex);
1668+ break;
1669+ default:
1670+ fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
1671+ }
1672+ if (r != 0)
1673+ return r;
1674+
1675+ token_ptr = GSS_C_NO_BUFFER;
1676+
1677+ do {
1678+ debug("Calling gss_init_sec_context");
1679+
1680+ maj_status = ssh_gssapi_init_ctx(ctxt,
1681+ kex->gss_deleg_creds, token_ptr, &send_tok,
1682+ &ret_flags);
1683+
1684+ if (GSS_ERROR(maj_status)) {
1685+ /* XXX Useles code: Missing send? */
1686+ if (send_tok.length != 0) {
1687+ if ((r = sshpkt_start(ssh,
1688+ SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
1689+ (r = sshpkt_put_string(ssh, send_tok.value,
1690+ send_tok.length)) != 0)
1691+ fatal("sshpkt failed: %s", ssh_err(r));
1692+ }
1693+ fatal("gss_init_context failed");
1694+ }
1695+
1696+ /* If we've got an old receive buffer get rid of it */
1697+ if (token_ptr != GSS_C_NO_BUFFER)
1698+ gss_release_buffer(&min_status, &recv_tok);
1699+
1700+ if (maj_status == GSS_S_COMPLETE) {
1701+ /* If mutual state flag is not true, kex fails */
1702+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
1703+ fatal("Mutual authentication failed");
1704+
1705+ /* If integ avail flag is not true kex fails */
1706+ if (!(ret_flags & GSS_C_INTEG_FLAG))
1707+ fatal("Integrity check failed");
1708+ }
1709+
1710+ /*
1711+ * If we have data to send, then the last message that we
1712+ * received cannot have been a 'complete'.
1713+ */
1714+ if (send_tok.length != 0) {
1715+ if (first) {
1716+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
1717+ (r = sshpkt_put_string(ssh, send_tok.value,
1718+ send_tok.length)) != 0 ||
1719+ (r = sshpkt_put_stringb(ssh, kex->client_pub)) != 0)
1720+ fatal("failed to construct packet: %s", ssh_err(r));
1721+ first = 0;
1722+ } else {
1723+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
1724+ (r = sshpkt_put_string(ssh, send_tok.value,
1725+ send_tok.length)) != 0)
1726+ fatal("failed to construct packet: %s", ssh_err(r));
1727+ }
1728+ if ((r = sshpkt_send(ssh)) != 0)
1729+ fatal("failed to send packet: %s", ssh_err(r));
1730+ gss_release_buffer(&min_status, &send_tok);
1731+
1732+ /* If we've sent them data, they should reply */
1733+ do {
1734+ type = ssh_packet_read(ssh);
1735+ if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
1736+ debug("Received KEXGSS_HOSTKEY");
1737+ if (server_host_key_blob)
1738+ fatal("Server host key received more than once");
1739+ if ((r = sshpkt_getb_froms(ssh, &server_host_key_blob)) != 0)
1740+ fatal("Failed to read server host key: %s", ssh_err(r));
1741+ }
1742+ } while (type == SSH2_MSG_KEXGSS_HOSTKEY);
1743+
1744+ switch (type) {
1745+ case SSH2_MSG_KEXGSS_CONTINUE:
1746+ debug("Received GSSAPI_CONTINUE");
1747+ if (maj_status == GSS_S_COMPLETE)
1748+ fatal("GSSAPI Continue received from server when complete");
1749+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
1750+ &recv_tok)) != 0 ||
1751+ (r = sshpkt_get_end(ssh)) != 0)
1752+ fatal("Failed to read token: %s", ssh_err(r));
1753+ break;
1754+ case SSH2_MSG_KEXGSS_COMPLETE:
1755+ debug("Received GSSAPI_COMPLETE");
1756+ if (msg_tok.value != NULL)
1757+ fatal("Received GSSAPI_COMPLETE twice?");
1758+ if ((r = sshpkt_getb_froms(ssh, &server_blob)) != 0 ||
1759+ (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
1760+ &msg_tok)) != 0)
1761+ fatal("Failed to read message: %s", ssh_err(r));
1762+
1763+ /* Is there a token included? */
1764+ if ((r = sshpkt_get_u8(ssh, &c)) != 0)
1765+ fatal("sshpkt failed: %s", ssh_err(r));
1766+ if (c) {
1767+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(
1768+ ssh, &recv_tok)) != 0)
1769+ fatal("Failed to read token: %s", ssh_err(r));
1770+ /* If we're already complete - protocol error */
1771+ if (maj_status == GSS_S_COMPLETE)
1772+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
1773+ } else {
1774+ /* No token included */
1775+ if (maj_status != GSS_S_COMPLETE)
1776+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
1777+ }
1778+ if ((r = sshpkt_get_end(ssh)) != 0) {
1779+ fatal("Expecting end of packet.");
1780+ }
1781+ break;
1782+ case SSH2_MSG_KEXGSS_ERROR:
1783+ debug("Received Error");
1784+ if ((r = sshpkt_get_u32(ssh, &maj_status)) != 0 ||
1785+ (r = sshpkt_get_u32(ssh, &min_status)) != 0 ||
1786+ (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
1787+ (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* lang tag */
1788+ (r = sshpkt_get_end(ssh)) != 0)
1789+ fatal("sshpkt_get failed: %s", ssh_err(r));
1790+ fatal("GSSAPI Error: \n%.400s", msg);
1791+ default:
1792+ sshpkt_disconnect(ssh, "Protocol error: didn't expect packet type %d",
1793+ type);
1794+ }
1795+ token_ptr = &recv_tok;
1796+ } else {
1797+ /* No data, and not complete */
1798+ if (maj_status != GSS_S_COMPLETE)
1799+ fatal("Not complete, and no token output");
1800+ }
1801+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
1802+
1803+ /*
1804+ * We _must_ have received a COMPLETE message in reply from the
1805+ * server, which will have set server_blob and msg_tok
1806+ */
1807+
1808+ if (type != SSH2_MSG_KEXGSS_COMPLETE)
1809+ fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
1810+
1811+ /* compute shared secret */
1812+ switch (kex->kex_type) {
1813+ case KEX_GSS_GRP1_SHA1:
1814+ case KEX_GSS_GRP14_SHA1:
1815+ case KEX_GSS_GRP14_SHA256:
1816+ case KEX_GSS_GRP16_SHA512:
1817+ r = kex_dh_dec(kex, server_blob, &shared_secret);
1818+ break;
1819+ case KEX_GSS_C25519_SHA256:
1820+ if (sshbuf_ptr(server_blob)[sshbuf_len(server_blob)] & 0x80)
1821+ fatal("The received key has MSB of last octet set!");
1822+ r = kex_c25519_dec(kex, server_blob, &shared_secret);
1823+ break;
1824+ case KEX_GSS_NISTP256_SHA256:
1825+ if (sshbuf_len(server_blob) != 65)
1826+ fatal("The received NIST-P256 key did not match"
1827+ "expected length (expected 65, got %zu)", sshbuf_len(server_blob));
1828+
1829+ if (sshbuf_ptr(server_blob)[0] != POINT_CONVERSION_UNCOMPRESSED)
1830+ fatal("The received NIST-P256 key does not have first octet 0x04");
1831+
1832+ r = kex_ecdh_dec(kex, server_blob, &shared_secret);
1833+ break;
1834+ default:
1835+ r = SSH_ERR_INVALID_ARGUMENT;
1836+ break;
1837+ }
1838+ if (r != 0)
1839+ goto out;
1840+
1841+ if ((empty = sshbuf_new()) == NULL) {
1842+ r = SSH_ERR_ALLOC_FAIL;
1843+ goto out;
1844+ }
1845+
1846+ hashlen = sizeof(hash);
1847+ if ((r = kex_gen_hash(
1848+ kex->hash_alg,
1849+ kex->client_version,
1850+ kex->server_version,
1851+ kex->my,
1852+ kex->peer,
1853+ (server_host_key_blob ? server_host_key_blob : empty),
1854+ kex->client_pub,
1855+ server_blob,
1856+ shared_secret,
1857+ hash, &hashlen)) != 0)
1858+ fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
1859+
1860+ gssbuf.value = hash;
1861+ gssbuf.length = hashlen;
1862+
1863+ /* Verify that the hash matches the MIC we just got. */
1864+ if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
1865+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
1866+
1867+ gss_release_buffer(&min_status, &msg_tok);
1868+
1869+ if (kex->gss_deleg_creds)
1870+ ssh_gssapi_credentials_updated(ctxt);
1871+
1872+ if (gss_kex_context == NULL)
1873+ gss_kex_context = ctxt;
1874+ else
1875+ ssh_gssapi_delete_ctx(&ctxt);
1876+
1877+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
1878+ r = kex_send_newkeys(ssh);
1879+
1880+out:
1881+ explicit_bzero(hash, sizeof(hash));
1882+ explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
1883+ sshbuf_free(empty);
1884+ sshbuf_free(server_host_key_blob);
1885+ sshbuf_free(server_blob);
1886+ sshbuf_free(shared_secret);
1887+ sshbuf_free(kex->client_pub);
1888+ kex->client_pub = NULL;
1889+ return r;
1890+}
1891+
1892+int
1893+kexgssgex_client(struct ssh *ssh)
1894+{
1895+ struct kex *kex = ssh->kex;
1896+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER,
1897+ recv_tok = GSS_C_EMPTY_BUFFER, gssbuf,
1898+ msg_tok = GSS_C_EMPTY_BUFFER, *token_ptr;
1899+ Gssctxt *ctxt;
1900+ OM_uint32 maj_status, min_status, ret_flags;
1901+ struct sshbuf *shared_secret = NULL;
1902+ BIGNUM *p = NULL;
1903+ BIGNUM *g = NULL;
1904+ struct sshbuf *buf = NULL;
1905+ struct sshbuf *server_host_key_blob = NULL;
1906+ struct sshbuf *server_blob = NULL;
1907+ BIGNUM *dh_server_pub = NULL;
1908+ u_char *msg;
1909+ int type = 0;
1910+ int first = 1;
1911+ u_char hash[SSH_DIGEST_MAX_LENGTH];
1912+ size_t hashlen;
1913+ const BIGNUM *pub_key, *dh_p, *dh_g;
1914+ int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
1915+ struct sshbuf *empty = NULL;
1916+ u_char c;
1917+ int r;
1918+
1919+ /* Initialise our GSSAPI world */
1920+ ssh_gssapi_build_ctx(&ctxt);
1921+ if (ssh_gssapi_id_kex(ctxt, kex->name, kex->kex_type)
1922+ == GSS_C_NO_OID)
1923+ fatal("Couldn't identify host exchange");
1924+
1925+ if (ssh_gssapi_import_name(ctxt, kex->gss_host))
1926+ fatal("Couldn't import hostname");
1927+
1928+ if (kex->gss_client &&
1929+ ssh_gssapi_client_identity(ctxt, kex->gss_client))
1930+ fatal("Couldn't acquire client credentials");
1931+
1932+ debug("Doing group exchange");
1933+ nbits = dh_estimate(kex->dh_need * 8);
1934+
1935+ kex->min = DH_GRP_MIN;
1936+ kex->max = DH_GRP_MAX;
1937+ kex->nbits = nbits;
1938+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUPREQ)) != 0 ||
1939+ (r = sshpkt_put_u32(ssh, min)) != 0 ||
1940+ (r = sshpkt_put_u32(ssh, nbits)) != 0 ||
1941+ (r = sshpkt_put_u32(ssh, max)) != 0 ||
1942+ (r = sshpkt_send(ssh)) != 0)
1943+ fatal("Failed to construct a packet: %s", ssh_err(r));
1944+
1945+ if ((r = ssh_packet_read_expect(ssh, SSH2_MSG_KEXGSS_GROUP)) != 0)
1946+ fatal("Error: %s", ssh_err(r));
1947+
1948+ if ((r = sshpkt_get_bignum2(ssh, &p)) != 0 ||
1949+ (r = sshpkt_get_bignum2(ssh, &g)) != 0 ||
1950+ (r = sshpkt_get_end(ssh)) != 0)
1951+ fatal("shpkt_get_bignum2 failed: %s", ssh_err(r));
1952+
1953+ if (BN_num_bits(p) < min || BN_num_bits(p) > max)
1954+ fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
1955+ min, BN_num_bits(p), max);
1956+
1957+ if ((kex->dh = dh_new_group(g, p)) == NULL)
1958+ fatal("dn_new_group() failed");
1959+ p = g = NULL; /* belong to kex->dh now */
1960+
1961+ if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
1962+ goto out;
1963+ DH_get0_key(kex->dh, &pub_key, NULL);
1964+
1965+ token_ptr = GSS_C_NO_BUFFER;
1966+
1967+ do {
1968+ /* Step 2 - call GSS_Init_sec_context() */
1969+ debug("Calling gss_init_sec_context");
1970+
1971+ maj_status = ssh_gssapi_init_ctx(ctxt,
1972+ kex->gss_deleg_creds, token_ptr, &send_tok,
1973+ &ret_flags);
1974+
1975+ if (GSS_ERROR(maj_status)) {
1976+ /* XXX Useles code: Missing send? */
1977+ if (send_tok.length != 0) {
1978+ if ((r = sshpkt_start(ssh,
1979+ SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
1980+ (r = sshpkt_put_string(ssh, send_tok.value,
1981+ send_tok.length)) != 0)
1982+ fatal("sshpkt failed: %s", ssh_err(r));
1983+ }
1984+ fatal("gss_init_context failed");
1985+ }
1986+
1987+ /* If we've got an old receive buffer get rid of it */
1988+ if (token_ptr != GSS_C_NO_BUFFER)
1989+ gss_release_buffer(&min_status, &recv_tok);
1990+
1991+ if (maj_status == GSS_S_COMPLETE) {
1992+ /* If mutual state flag is not true, kex fails */
1993+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
1994+ fatal("Mutual authentication failed");
1995+
1996+ /* If integ avail flag is not true kex fails */
1997+ if (!(ret_flags & GSS_C_INTEG_FLAG))
1998+ fatal("Integrity check failed");
1999+ }
2000+
2001+ /*
2002+ * If we have data to send, then the last message that we
2003+ * received cannot have been a 'complete'.
2004+ */
2005+ if (send_tok.length != 0) {
2006+ if (first) {
2007+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
2008+ (r = sshpkt_put_string(ssh, send_tok.value,
2009+ send_tok.length)) != 0 ||
2010+ (r = sshpkt_put_bignum2(ssh, pub_key)) != 0)
2011+ fatal("sshpkt failed: %s", ssh_err(r));
2012+ first = 0;
2013+ } else {
2014+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
2015+ (r = sshpkt_put_string(ssh,send_tok.value,
2016+ send_tok.length)) != 0)
2017+ fatal("sshpkt failed: %s", ssh_err(r));
2018+ }
2019+ if ((r = sshpkt_send(ssh)) != 0)
2020+ fatal("sshpkt_send failed: %s", ssh_err(r));
2021+ gss_release_buffer(&min_status, &send_tok);
2022+
2023+ /* If we've sent them data, they should reply */
2024+ do {
2025+ type = ssh_packet_read(ssh);
2026+ if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
2027+ debug("Received KEXGSS_HOSTKEY");
2028+ if (server_host_key_blob)
2029+ fatal("Server host key received more than once");
2030+ if ((r = sshpkt_getb_froms(ssh, &server_host_key_blob)) != 0)
2031+ fatal("sshpkt failed: %s", ssh_err(r));
2032+ }
2033+ } while (type == SSH2_MSG_KEXGSS_HOSTKEY);
2034+
2035+ switch (type) {
2036+ case SSH2_MSG_KEXGSS_CONTINUE:
2037+ debug("Received GSSAPI_CONTINUE");
2038+ if (maj_status == GSS_S_COMPLETE)
2039+ fatal("GSSAPI Continue received from server when complete");
2040+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2041+ &recv_tok)) != 0 ||
2042+ (r = sshpkt_get_end(ssh)) != 0)
2043+ fatal("sshpkt failed: %s", ssh_err(r));
2044+ break;
2045+ case SSH2_MSG_KEXGSS_COMPLETE:
2046+ debug("Received GSSAPI_COMPLETE");
2047+ if (msg_tok.value != NULL)
2048+ fatal("Received GSSAPI_COMPLETE twice?");
2049+ if ((r = sshpkt_getb_froms(ssh, &server_blob)) != 0 ||
2050+ (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2051+ &msg_tok)) != 0)
2052+ fatal("sshpkt failed: %s", ssh_err(r));
2053+
2054+ /* Is there a token included? */
2055+ if ((r = sshpkt_get_u8(ssh, &c)) != 0)
2056+ fatal("sshpkt failed: %s", ssh_err(r));
2057+ if (c) {
2058+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(
2059+ ssh, &recv_tok)) != 0 ||
2060+ (r = sshpkt_get_end(ssh)) != 0)
2061+ fatal("sshpkt failed: %s", ssh_err(r));
2062+ /* If we're already complete - protocol error */
2063+ if (maj_status == GSS_S_COMPLETE)
2064+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
2065+ } else {
2066+ /* No token included */
2067+ if (maj_status != GSS_S_COMPLETE)
2068+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
2069+ }
2070+ break;
2071+ case SSH2_MSG_KEXGSS_ERROR:
2072+ debug("Received Error");
2073+ if ((r = sshpkt_get_u32(ssh, &maj_status)) != 0 ||
2074+ (r = sshpkt_get_u32(ssh, &min_status)) != 0 ||
2075+ (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
2076+ (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* lang tag */
2077+ (r = sshpkt_get_end(ssh)) != 0)
2078+ fatal("sshpkt failed: %s", ssh_err(r));
2079+ fatal("GSSAPI Error: \n%.400s", msg);
2080+ default:
2081+ sshpkt_disconnect(ssh, "Protocol error: didn't expect packet type %d",
2082+ type);
2083+ }
2084+ token_ptr = &recv_tok;
2085+ } else {
2086+ /* No data, and not complete */
2087+ if (maj_status != GSS_S_COMPLETE)
2088+ fatal("Not complete, and no token output");
2089+ }
2090+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
2091+
2092+ /*
2093+ * We _must_ have received a COMPLETE message in reply from the
2094+ * server, which will have set dh_server_pub and msg_tok
2095+ */
2096+
2097+ if (type != SSH2_MSG_KEXGSS_COMPLETE)
2098+ fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
2099+
2100+ /* 7. C verifies that the key Q_S is valid */
2101+ /* 8. C computes shared secret */
2102+ if ((buf = sshbuf_new()) == NULL ||
2103+ (r = sshbuf_put_stringb(buf, server_blob)) != 0 ||
2104+ (r = sshbuf_get_bignum2(buf, &dh_server_pub)) != 0)
2105+ goto out;
2106+ sshbuf_free(buf);
2107+ buf = NULL;
2108+
2109+ if ((shared_secret = sshbuf_new()) == NULL) {
2110+ r = SSH_ERR_ALLOC_FAIL;
2111+ goto out;
2112+ }
2113+
2114+ if ((r = kex_dh_compute_key(kex, dh_server_pub, shared_secret)) != 0)
2115+ goto out;
2116+ if ((empty = sshbuf_new()) == NULL) {
2117+ r = SSH_ERR_ALLOC_FAIL;
2118+ goto out;
2119+ }
2120+
2121+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
2122+ hashlen = sizeof(hash);
2123+ if ((r = kexgex_hash(
2124+ kex->hash_alg,
2125+ kex->client_version,
2126+ kex->server_version,
2127+ kex->my,
2128+ kex->peer,
2129+ (server_host_key_blob ? server_host_key_blob : empty),
2130+ kex->min, kex->nbits, kex->max,
2131+ dh_p, dh_g,
2132+ pub_key,
2133+ dh_server_pub,
2134+ sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
2135+ hash, &hashlen)) != 0)
2136+ fatal("Failed to calculate hash: %s", ssh_err(r));
2137+
2138+ gssbuf.value = hash;
2139+ gssbuf.length = hashlen;
2140+
2141+ /* Verify that the hash matches the MIC we just got. */
2142+ if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
2143+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
2144+
2145+ gss_release_buffer(&min_status, &msg_tok);
2146+
2147+ /* save session id */
2148+ if (kex->session_id == NULL) {
2149+ kex->session_id_len = hashlen;
2150+ kex->session_id = xmalloc(kex->session_id_len);
2151+ memcpy(kex->session_id, hash, kex->session_id_len);
2152+ }
2153+
2154+ if (kex->gss_deleg_creds)
2155+ ssh_gssapi_credentials_updated(ctxt);
2156+
2157+ if (gss_kex_context == NULL)
2158+ gss_kex_context = ctxt;
2159+ else
2160+ ssh_gssapi_delete_ctx(&ctxt);
2161+
2162+ /* Finally derive the keys and send them */
2163+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
2164+ r = kex_send_newkeys(ssh);
2165+out:
2166+ sshbuf_free(buf);
2167+ sshbuf_free(server_blob);
2168+ sshbuf_free(empty);
2169+ explicit_bzero(hash, sizeof(hash));
2170+ DH_free(kex->dh);
2171+ kex->dh = NULL;
2172+ BN_clear_free(dh_server_pub);
2173+ sshbuf_free(shared_secret);
2174+ sshbuf_free(server_host_key_blob);
2175+ return r;
2176+}
2177+#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
2178diff --git a/kexgsss.c b/kexgsss.c
2179new file mode 100644
2180index 000000000..60bc02deb
2181--- /dev/null
2182+++ b/kexgsss.c
2183@@ -0,0 +1,474 @@
2184+/*
2185+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
2186+ *
2187+ * Redistribution and use in source and binary forms, with or without
2188+ * modification, are permitted provided that the following conditions
2189+ * are met:
2190+ * 1. Redistributions of source code must retain the above copyright
2191+ * notice, this list of conditions and the following disclaimer.
2192+ * 2. Redistributions in binary form must reproduce the above copyright
2193+ * notice, this list of conditions and the following disclaimer in the
2194+ * documentation and/or other materials provided with the distribution.
2195+ *
2196+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
2197+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
2198+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
2199+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
2200+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
2201+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
2202+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
2203+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
2204+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
2205+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
2206+ */
2207+
2208+#include "includes.h"
2209+
2210+#if defined(GSSAPI) && defined(WITH_OPENSSL)
2211+
2212+#include <string.h>
2213+
2214+#include <openssl/crypto.h>
2215+#include <openssl/bn.h>
2216+
2217+#include "xmalloc.h"
2218+#include "sshbuf.h"
2219+#include "ssh2.h"
2220+#include "sshkey.h"
2221+#include "cipher.h"
2222+#include "kex.h"
2223+#include "log.h"
2224+#include "packet.h"
2225+#include "dh.h"
2226+#include "ssh-gss.h"
2227+#include "monitor_wrap.h"
2228+#include "misc.h" /* servconf.h needs misc.h for struct ForwardOptions */
2229+#include "servconf.h"
2230+#include "ssh-gss.h"
2231+#include "digest.h"
2232+#include "ssherr.h"
2233+
2234+extern ServerOptions options;
2235+
2236+int
2237+kexgss_server(struct ssh *ssh)
2238+{
2239+ struct kex *kex = ssh->kex;
2240+ OM_uint32 maj_status, min_status;
2241+
2242+ /*
2243+ * Some GSSAPI implementations use the input value of ret_flags (an
2244+ * output variable) as a means of triggering mechanism specific
2245+ * features. Initializing it to zero avoids inadvertently
2246+ * activating this non-standard behaviour.
2247+ */
2248+
2249+ OM_uint32 ret_flags = 0;
2250+ gss_buffer_desc gssbuf, recv_tok, msg_tok;
2251+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
2252+ Gssctxt *ctxt = NULL;
2253+ struct sshbuf *shared_secret = NULL;
2254+ struct sshbuf *client_pubkey = NULL;
2255+ struct sshbuf *server_pubkey = NULL;
2256+ struct sshbuf *empty = sshbuf_new();
2257+ int type = 0;
2258+ gss_OID oid;
2259+ char *mechs;
2260+ u_char hash[SSH_DIGEST_MAX_LENGTH];
2261+ size_t hashlen;
2262+ int r;
2263+
2264+ /* Initialise GSSAPI */
2265+
2266+ /* If we're rekeying, privsep means that some of the private structures
2267+ * in the GSSAPI code are no longer available. This kludges them back
2268+ * into life
2269+ */
2270+ if (!ssh_gssapi_oid_table_ok()) {
2271+ mechs = ssh_gssapi_server_mechanisms();
2272+ free(mechs);
2273+ }
2274+
2275+ debug2("%s: Identifying %s", __func__, kex->name);
2276+ oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
2277+ if (oid == GSS_C_NO_OID)
2278+ fatal("Unknown gssapi mechanism");
2279+
2280+ debug2("%s: Acquiring credentials", __func__);
2281+
2282+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
2283+ fatal("Unable to acquire credentials for the server");
2284+
2285+ do {
2286+ debug("Wait SSH2_MSG_KEXGSS_INIT");
2287+ type = ssh_packet_read(ssh);
2288+ switch(type) {
2289+ case SSH2_MSG_KEXGSS_INIT:
2290+ if (client_pubkey != NULL)
2291+ fatal("Received KEXGSS_INIT after initialising");
2292+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2293+ &recv_tok)) != 0 ||
2294+ (r = sshpkt_getb_froms(ssh, &client_pubkey)) != 0 ||
2295+ (r = sshpkt_get_end(ssh)) != 0)
2296+ fatal("sshpkt failed: %s", ssh_err(r));
2297+
2298+ switch (kex->kex_type) {
2299+ case KEX_GSS_GRP1_SHA1:
2300+ case KEX_GSS_GRP14_SHA1:
2301+ case KEX_GSS_GRP14_SHA256:
2302+ case KEX_GSS_GRP16_SHA512:
2303+ r = kex_dh_enc(kex, client_pubkey, &server_pubkey,
2304+ &shared_secret);
2305+ break;
2306+ case KEX_GSS_NISTP256_SHA256:
2307+ r = kex_ecdh_enc(kex, client_pubkey, &server_pubkey,
2308+ &shared_secret);
2309+ break;
2310+ case KEX_GSS_C25519_SHA256:
2311+ r = kex_c25519_enc(kex, client_pubkey, &server_pubkey,
2312+ &shared_secret);
2313+ break;
2314+ default:
2315+ fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
2316+ }
2317+ if (r != 0)
2318+ goto out;
2319+
2320+ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
2321+ break;
2322+ case SSH2_MSG_KEXGSS_CONTINUE:
2323+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2324+ &recv_tok)) != 0 ||
2325+ (r = sshpkt_get_end(ssh)) != 0)
2326+ fatal("sshpkt failed: %s", ssh_err(r));
2327+ break;
2328+ default:
2329+ sshpkt_disconnect(ssh,
2330+ "Protocol error: didn't expect packet type %d",
2331+ type);
2332+ }
2333+
2334+ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
2335+ &send_tok, &ret_flags));
2336+
2337+ gss_release_buffer(&min_status, &recv_tok);
2338+
2339+ if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
2340+ fatal("Zero length token output when incomplete");
2341+
2342+ if (client_pubkey == NULL)
2343+ fatal("No client public key");
2344+
2345+ if (maj_status & GSS_S_CONTINUE_NEEDED) {
2346+ debug("Sending GSSAPI_CONTINUE");
2347+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
2348+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
2349+ (r = sshpkt_send(ssh)) != 0)
2350+ fatal("sshpkt failed: %s", ssh_err(r));
2351+ gss_release_buffer(&min_status, &send_tok);
2352+ }
2353+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
2354+
2355+ if (GSS_ERROR(maj_status)) {
2356+ if (send_tok.length > 0) {
2357+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
2358+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
2359+ (r = sshpkt_send(ssh)) != 0)
2360+ fatal("sshpkt failed: %s", ssh_err(r));
2361+ }
2362+ fatal("accept_ctx died");
2363+ }
2364+
2365+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
2366+ fatal("Mutual Authentication flag wasn't set");
2367+
2368+ if (!(ret_flags & GSS_C_INTEG_FLAG))
2369+ fatal("Integrity flag wasn't set");
2370+
2371+ hashlen = sizeof(hash);
2372+ if ((r = kex_gen_hash(
2373+ kex->hash_alg,
2374+ kex->client_version,
2375+ kex->server_version,
2376+ kex->peer,
2377+ kex->my,
2378+ empty,
2379+ client_pubkey,
2380+ server_pubkey,
2381+ shared_secret,
2382+ hash, &hashlen)) != 0)
2383+ goto out;
2384+
2385+ gssbuf.value = hash;
2386+ gssbuf.length = hashlen;
2387+
2388+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt, &gssbuf, &msg_tok))))
2389+ fatal("Couldn't get MIC");
2390+
2391+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
2392+ (r = sshpkt_put_stringb(ssh, server_pubkey)) != 0 ||
2393+ (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
2394+ fatal("sshpkt failed: %s", ssh_err(r));
2395+
2396+ if (send_tok.length != 0) {
2397+ if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
2398+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
2399+ fatal("sshpkt failed: %s", ssh_err(r));
2400+ } else {
2401+ if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
2402+ fatal("sshpkt failed: %s", ssh_err(r));
2403+ }
2404+ if ((r = sshpkt_send(ssh)) != 0)
2405+ fatal("sshpkt_send failed: %s", ssh_err(r));
2406+
2407+ gss_release_buffer(&min_status, &send_tok);
2408+ gss_release_buffer(&min_status, &msg_tok);
2409+
2410+ if (gss_kex_context == NULL)
2411+ gss_kex_context = ctxt;
2412+ else
2413+ ssh_gssapi_delete_ctx(&ctxt);
2414+
2415+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
2416+ r = kex_send_newkeys(ssh);
2417+
2418+ /* If this was a rekey, then save out any delegated credentials we
2419+ * just exchanged. */
2420+ if (options.gss_store_rekey)
2421+ ssh_gssapi_rekey_creds();
2422+out:
2423+ sshbuf_free(empty);
2424+ explicit_bzero(hash, sizeof(hash));
2425+ sshbuf_free(shared_secret);
2426+ sshbuf_free(client_pubkey);
2427+ sshbuf_free(server_pubkey);
2428+ return r;
2429+}
2430+
2431+int
2432+kexgssgex_server(struct ssh *ssh)
2433+{
2434+ struct kex *kex = ssh->kex;
2435+ OM_uint32 maj_status, min_status;
2436+
2437+ /*
2438+ * Some GSSAPI implementations use the input value of ret_flags (an
2439+ * output variable) as a means of triggering mechanism specific
2440+ * features. Initializing it to zero avoids inadvertently
2441+ * activating this non-standard behaviour.
2442+ */
2443+
2444+ OM_uint32 ret_flags = 0;
2445+ gss_buffer_desc gssbuf, recv_tok, msg_tok;
2446+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
2447+ Gssctxt *ctxt = NULL;
2448+ struct sshbuf *shared_secret = NULL;
2449+ int type = 0;
2450+ gss_OID oid;
2451+ char *mechs;
2452+ u_char hash[SSH_DIGEST_MAX_LENGTH];
2453+ size_t hashlen;
2454+ BIGNUM *dh_client_pub = NULL;
2455+ const BIGNUM *pub_key, *dh_p, *dh_g;
2456+ int min = -1, max = -1, nbits = -1;
2457+ int cmin = -1, cmax = -1; /* client proposal */
2458+ struct sshbuf *empty = sshbuf_new();
2459+ int r;
2460+
2461+ /* Initialise GSSAPI */
2462+
2463+ /* If we're rekeying, privsep means that some of the private structures
2464+ * in the GSSAPI code are no longer available. This kludges them back
2465+ * into life
2466+ */
2467+ if (!ssh_gssapi_oid_table_ok())
2468+ if ((mechs = ssh_gssapi_server_mechanisms()))
2469+ free(mechs);
2470+
2471+ debug2("%s: Identifying %s", __func__, kex->name);
2472+ oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
2473+ if (oid == GSS_C_NO_OID)
2474+ fatal("Unknown gssapi mechanism");
2475+
2476+ debug2("%s: Acquiring credentials", __func__);
2477+
2478+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
2479+ fatal("Unable to acquire credentials for the server");
2480+
2481+ /* 5. S generates an ephemeral key pair (do the allocations early) */
2482+ debug("Doing group exchange");
2483+ ssh_packet_read_expect(ssh, SSH2_MSG_KEXGSS_GROUPREQ);
2484+ /* store client proposal to provide valid signature */
2485+ if ((r = sshpkt_get_u32(ssh, &cmin)) != 0 ||
2486+ (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
2487+ (r = sshpkt_get_u32(ssh, &cmax)) != 0 ||
2488+ (r = sshpkt_get_end(ssh)) != 0)
2489+ fatal("sshpkt failed: %s", ssh_err(r));
2490+ kex->nbits = nbits;
2491+ kex->min = cmin;
2492+ kex->max = cmax;
2493+ min = MAX(DH_GRP_MIN, cmin);
2494+ max = MIN(DH_GRP_MAX, cmax);
2495+ nbits = MAXIMUM(DH_GRP_MIN, nbits);
2496+ nbits = MINIMUM(DH_GRP_MAX, nbits);
2497+ if (max < min || nbits < min || max < nbits)
2498+ fatal("GSS_GEX, bad parameters: %d !< %d !< %d",
2499+ min, nbits, max);
2500+ kex->dh = PRIVSEP(choose_dh(min, nbits, max));
2501+ if (kex->dh == NULL) {
2502+ sshpkt_disconnect(ssh, "Protocol error: no matching group found");
2503+ fatal("Protocol error: no matching group found");
2504+ }
2505+
2506+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
2507+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUP)) != 0 ||
2508+ (r = sshpkt_put_bignum2(ssh, dh_p)) != 0 ||
2509+ (r = sshpkt_put_bignum2(ssh, dh_g)) != 0 ||
2510+ (r = sshpkt_send(ssh)) != 0)
2511+ fatal("sshpkt failed: %s", ssh_err(r));
2512+
2513+ if ((r = ssh_packet_write_wait(ssh)) != 0)
2514+ fatal("ssh_packet_write_wait: %s", ssh_err(r));
2515+
2516+ /* Compute our exchange value in parallel with the client */
2517+ if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
2518+ goto out;
2519+
2520+ do {
2521+ debug("Wait SSH2_MSG_GSSAPI_INIT");
2522+ type = ssh_packet_read(ssh);
2523+ switch(type) {
2524+ case SSH2_MSG_KEXGSS_INIT:
2525+ if (dh_client_pub != NULL)
2526+ fatal("Received KEXGSS_INIT after initialising");
2527+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2528+ &recv_tok)) != 0 ||
2529+ (r = sshpkt_get_bignum2(ssh, &dh_client_pub)) != 0 ||
2530+ (r = sshpkt_get_end(ssh)) != 0)
2531+ fatal("sshpkt failed: %s", ssh_err(r));
2532+
2533+ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
2534+ break;
2535+ case SSH2_MSG_KEXGSS_CONTINUE:
2536+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh,
2537+ &recv_tok)) != 0 ||
2538+ (r = sshpkt_get_end(ssh)) != 0)
2539+ fatal("sshpkt failed: %s", ssh_err(r));
2540+ break;
2541+ default:
2542+ sshpkt_disconnect(ssh,
2543+ "Protocol error: didn't expect packet type %d",
2544+ type);
2545+ }
2546+
2547+ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
2548+ &send_tok, &ret_flags));
2549+
2550+ gss_release_buffer(&min_status, &recv_tok);
2551+
2552+ if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
2553+ fatal("Zero length token output when incomplete");
2554+
2555+ if (dh_client_pub == NULL)
2556+ fatal("No client public key");
2557+
2558+ if (maj_status & GSS_S_CONTINUE_NEEDED) {
2559+ debug("Sending GSSAPI_CONTINUE");
2560+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
2561+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
2562+ (r = sshpkt_send(ssh)) != 0)
2563+ fatal("sshpkt failed: %s", ssh_err(r));
2564+ gss_release_buffer(&min_status, &send_tok);
2565+ }
2566+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
2567+
2568+ if (GSS_ERROR(maj_status)) {
2569+ if (send_tok.length > 0) {
2570+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
2571+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
2572+ (r = sshpkt_send(ssh)) != 0)
2573+ fatal("sshpkt failed: %s", ssh_err(r));
2574+ }
2575+ fatal("accept_ctx died");
2576+ }
2577+
2578+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
2579+ fatal("Mutual Authentication flag wasn't set");
2580+
2581+ if (!(ret_flags & GSS_C_INTEG_FLAG))
2582+ fatal("Integrity flag wasn't set");
2583+
2584+ /* calculate shared secret */
2585+ if ((shared_secret = sshbuf_new()) == NULL) {
2586+ r = SSH_ERR_ALLOC_FAIL;
2587+ goto out;
2588+ }
2589+ if ((r = kex_dh_compute_key(kex, dh_client_pub, shared_secret)) != 0)
2590+ goto out;
2591+
2592+ DH_get0_key(kex->dh, &pub_key, NULL);
2593+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
2594+ hashlen = sizeof(hash);
2595+ if ((r = kexgex_hash(
2596+ kex->hash_alg,
2597+ kex->client_version,
2598+ kex->server_version,
2599+ kex->peer,
2600+ kex->my,
2601+ empty,
2602+ cmin, nbits, cmax,
2603+ dh_p, dh_g,
2604+ dh_client_pub,
2605+ pub_key,
2606+ sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
2607+ hash, &hashlen)) != 0)
2608+ fatal("kexgex_hash failed: %s", ssh_err(r));
2609+
2610+ gssbuf.value = hash;
2611+ gssbuf.length = hashlen;
2612+
2613+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt, &gssbuf, &msg_tok))))
2614+ fatal("Couldn't get MIC");
2615+
2616+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
2617+ (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 ||
2618+ (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
2619+ fatal("sshpkt failed: %s", ssh_err(r));
2620+
2621+ if (send_tok.length != 0) {
2622+ if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
2623+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
2624+ fatal("sshpkt failed: %s", ssh_err(r));
2625+ } else {
2626+ if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
2627+ fatal("sshpkt failed: %s", ssh_err(r));
2628+ }
2629+ if ((r = sshpkt_send(ssh)) != 0)
2630+ fatal("sshpkt failed: %s", ssh_err(r));
2631+
2632+ gss_release_buffer(&min_status, &send_tok);
2633+ gss_release_buffer(&min_status, &msg_tok);
2634+
2635+ if (gss_kex_context == NULL)
2636+ gss_kex_context = ctxt;
2637+ else
2638+ ssh_gssapi_delete_ctx(&ctxt);
2639+
2640+ /* Finally derive the keys and send them */
2641+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
2642+ r = kex_send_newkeys(ssh);
2643+
2644+ /* If this was a rekey, then save out any delegated credentials we
2645+ * just exchanged. */
2646+ if (options.gss_store_rekey)
2647+ ssh_gssapi_rekey_creds();
2648+out:
2649+ sshbuf_free(empty);
2650+ explicit_bzero(hash, sizeof(hash));
2651+ DH_free(kex->dh);
2652+ kex->dh = NULL;
2653+ BN_clear_free(dh_client_pub);
2654+ sshbuf_free(shared_secret);
2655+ return r;
2656+}
2657+#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
2658diff --git a/monitor.c b/monitor.c
2659index 4cf79dfc9..11868952b 100644
2660--- a/monitor.c
2661+++ b/monitor.c
2662@@ -148,6 +148,8 @@ int mm_answer_gss_setup_ctx(struct ssh *, int, struct sshbuf *);
2663 int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
2664 int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
2665 int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
2666+int mm_answer_gss_sign(struct ssh *, int, struct sshbuf *);
2667+int mm_answer_gss_updatecreds(struct ssh *, int, struct sshbuf *);
2668 #endif
2669
2670 #ifdef SSH_AUDIT_EVENTS
2671@@ -220,11 +222,18 @@ struct mon_table mon_dispatch_proto20[] = {
2672 {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
2673 {MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
2674 {MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
2675+ {MONITOR_REQ_GSSSIGN, MON_ONCE, mm_answer_gss_sign},
2676 #endif
2677 {0, 0, NULL}
2678 };
2679
2680 struct mon_table mon_dispatch_postauth20[] = {
2681+#ifdef GSSAPI
2682+ {MONITOR_REQ_GSSSETUP, 0, mm_answer_gss_setup_ctx},
2683+ {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
2684+ {MONITOR_REQ_GSSSIGN, 0, mm_answer_gss_sign},
2685+ {MONITOR_REQ_GSSUPCREDS, 0, mm_answer_gss_updatecreds},
2686+#endif
2687 #ifdef WITH_OPENSSL
2688 {MONITOR_REQ_MODULI, 0, mm_answer_moduli},
2689 #endif
2690@@ -293,6 +302,10 @@ monitor_child_preauth(struct ssh *ssh, struct monitor *pmonitor)
2691 /* Permit requests for moduli and signatures */
2692 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
2693 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
2694+#ifdef GSSAPI
2695+ /* and for the GSSAPI key exchange */
2696+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
2697+#endif
2698
2699 /* The first few requests do not require asynchronous access */
2700 while (!authenticated) {
2701@@ -406,6 +419,10 @@ monitor_child_postauth(struct ssh *ssh, struct monitor *pmonitor)
2702 monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
2703 monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
2704 monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
2705+#ifdef GSSAPI
2706+ /* and for the GSSAPI key exchange */
2707+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
2708+#endif
2709
2710 if (auth_opts->permit_pty_flag) {
2711 monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
2712@@ -1725,6 +1742,17 @@ monitor_apply_keystate(struct ssh *ssh, struct monitor *pmonitor)
2713 # ifdef OPENSSL_HAS_ECC
2714 kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
2715 # endif
2716+# ifdef GSSAPI
2717+ if (options.gss_keyex) {
2718+ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
2719+ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
2720+ kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
2721+ kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
2722+ kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
2723+ kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
2724+ kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
2725+ }
2726+# endif
2727 #endif /* WITH_OPENSSL */
2728 kex->kex[KEX_C25519_SHA256] = kex_gen_server;
2729 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server;
2730@@ -1818,8 +1846,8 @@ mm_answer_gss_setup_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
2731 u_char *p;
2732 int r;
2733
2734- if (!options.gss_authentication)
2735- fatal("%s: GSSAPI authentication not enabled", __func__);
2736+ if (!options.gss_authentication && !options.gss_keyex)
2737+ fatal("%s: GSSAPI not enabled", __func__);
2738
2739 if ((r = sshbuf_get_string(m, &p, &len)) != 0)
2740 fatal("%s: buffer error: %s", __func__, ssh_err(r));
2741@@ -1851,8 +1879,8 @@ mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
2742 OM_uint32 flags = 0; /* GSI needs this */
2743 int r;
2744
2745- if (!options.gss_authentication)
2746- fatal("%s: GSSAPI authentication not enabled", __func__);
2747+ if (!options.gss_authentication && !options.gss_keyex)
2748+ fatal("%s: GSSAPI not enabled", __func__);
2749
2750 if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
2751 fatal("%s: buffer error: %s", __func__, ssh_err(r));
2752@@ -1872,6 +1900,7 @@ mm_answer_gss_accept_ctx(struct ssh *ssh, int sock, struct sshbuf *m)
2753 monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
2754 monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
2755 monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
2756+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSIGN, 1);
2757 }
2758 return (0);
2759 }
2760@@ -1883,8 +1912,8 @@ mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
2761 OM_uint32 ret;
2762 int r;
2763
2764- if (!options.gss_authentication)
2765- fatal("%s: GSSAPI authentication not enabled", __func__);
2766+ if (!options.gss_authentication && !options.gss_keyex)
2767+ fatal("%s: GSSAPI not enabled", __func__);
2768
2769 if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
2770 (r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
2771@@ -1910,13 +1939,17 @@ mm_answer_gss_checkmic(struct ssh *ssh, int sock, struct sshbuf *m)
2772 int
2773 mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
2774 {
2775- int r, authenticated;
2776+ int r, authenticated, kex;
2777 const char *displayname;
2778
2779- if (!options.gss_authentication)
2780- fatal("%s: GSSAPI authentication not enabled", __func__);
2781+ if (!options.gss_authentication && !options.gss_keyex)
2782+ fatal("%s: GSSAPI not enabled", __func__);
2783
2784- authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
2785+ if ((r = sshbuf_get_u32(m, &kex)) != 0)
2786+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2787+
2788+ authenticated = authctxt->valid &&
2789+ ssh_gssapi_userok(authctxt->user, authctxt->pw, kex);
2790
2791 sshbuf_reset(m);
2792 if ((r = sshbuf_put_u32(m, authenticated)) != 0)
2793@@ -1925,7 +1958,11 @@ mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
2794 debug3("%s: sending result %d", __func__, authenticated);
2795 mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
2796
2797- auth_method = "gssapi-with-mic";
2798+ if (kex) {
2799+ auth_method = "gssapi-keyex";
2800+ } else {
2801+ auth_method = "gssapi-with-mic";
2802+ }
2803
2804 if ((displayname = ssh_gssapi_displayname()) != NULL)
2805 auth2_record_info(authctxt, "%s", displayname);
2806@@ -1933,5 +1970,85 @@ mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
2807 /* Monitor loop will terminate if authenticated */
2808 return (authenticated);
2809 }
2810+
2811+int
2812+mm_answer_gss_sign(struct ssh *ssh, int socket, struct sshbuf *m)
2813+{
2814+ gss_buffer_desc data;
2815+ gss_buffer_desc hash = GSS_C_EMPTY_BUFFER;
2816+ OM_uint32 major, minor;
2817+ size_t len;
2818+ u_char *p = NULL;
2819+ int r;
2820+
2821+ if (!options.gss_authentication && !options.gss_keyex)
2822+ fatal("%s: GSSAPI not enabled", __func__);
2823+
2824+ if ((r = sshbuf_get_string(m, &p, &len)) != 0)
2825+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2826+ data.value = p;
2827+ data.length = len;
2828+ /* Lengths of SHA-1, SHA-256 and SHA-512 hashes that are used */
2829+ if (data.length != 20 && data.length != 32 && data.length != 64)
2830+ fatal("%s: data length incorrect: %d", __func__,
2831+ (int) data.length);
2832+
2833+ /* Save the session ID on the first time around */
2834+ if (session_id2_len == 0) {
2835+ session_id2_len = data.length;
2836+ session_id2 = xmalloc(session_id2_len);
2837+ memcpy(session_id2, data.value, session_id2_len);
2838+ }
2839+ major = ssh_gssapi_sign(gsscontext, &data, &hash);
2840+
2841+ free(data.value);
2842+
2843+ sshbuf_reset(m);
2844+
2845+ if ((r = sshbuf_put_u32(m, major)) != 0 ||
2846+ (r = sshbuf_put_string(m, hash.value, hash.length)) != 0)
2847+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2848+
2849+ mm_request_send(socket, MONITOR_ANS_GSSSIGN, m);
2850+
2851+ gss_release_buffer(&minor, &hash);
2852+
2853+ /* Turn on getpwnam permissions */
2854+ monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
2855+
2856+ /* And credential updating, for when rekeying */
2857+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSUPCREDS, 1);
2858+
2859+ return (0);
2860+}
2861+
2862+int
2863+mm_answer_gss_updatecreds(struct ssh *ssh, int socket, struct sshbuf *m) {
2864+ ssh_gssapi_ccache store;
2865+ int r, ok;
2866+
2867+ if (!options.gss_authentication && !options.gss_keyex)
2868+ fatal("%s: GSSAPI not enabled", __func__);
2869+
2870+ if ((r = sshbuf_get_string(m, (u_char **)&store.filename, NULL)) != 0 ||
2871+ (r = sshbuf_get_string(m, (u_char **)&store.envvar, NULL)) != 0 ||
2872+ (r = sshbuf_get_string(m, (u_char **)&store.envval, NULL)) != 0)
2873+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2874+
2875+ ok = ssh_gssapi_update_creds(&store);
2876+
2877+ free(store.filename);
2878+ free(store.envvar);
2879+ free(store.envval);
2880+
2881+ sshbuf_reset(m);
2882+ if ((r = sshbuf_put_u32(m, ok)) != 0)
2883+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2884+
2885+ mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
2886+
2887+ return(0);
2888+}
2889+
2890 #endif /* GSSAPI */
2891
2892diff --git a/monitor.h b/monitor.h
2893index 683e5e071..2b1a2d590 100644
2894--- a/monitor.h
2895+++ b/monitor.h
2896@@ -63,6 +63,8 @@ enum monitor_reqtype {
2897 MONITOR_REQ_PAM_FREE_CTX = 110, MONITOR_ANS_PAM_FREE_CTX = 111,
2898 MONITOR_REQ_AUDIT_EVENT = 112, MONITOR_REQ_AUDIT_COMMAND = 113,
2899
2900+ MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151,
2901+ MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153,
2902 };
2903
2904 struct ssh;
2905diff --git a/monitor_wrap.c b/monitor_wrap.c
2906index 5e38d83eb..0e78cd006 100644
2907--- a/monitor_wrap.c
2908+++ b/monitor_wrap.c
2909@@ -993,13 +993,15 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
2910 }
2911
2912 int
2913-mm_ssh_gssapi_userok(char *user)
2914+mm_ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
2915 {
2916 struct sshbuf *m;
2917 int r, authenticated = 0;
2918
2919 if ((m = sshbuf_new()) == NULL)
2920 fatal("%s: sshbuf_new failed", __func__);
2921+ if ((r = sshbuf_put_u32(m, kex)) != 0)
2922+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2923
2924 mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, m);
2925 mm_request_receive_expect(pmonitor->m_recvfd,
2926@@ -1012,4 +1014,57 @@ mm_ssh_gssapi_userok(char *user)
2927 debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not ");
2928 return (authenticated);
2929 }
2930+
2931+OM_uint32
2932+mm_ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *data, gss_buffer_desc *hash)
2933+{
2934+ struct sshbuf *m;
2935+ OM_uint32 major;
2936+ int r;
2937+
2938+ if ((m = sshbuf_new()) == NULL)
2939+ fatal("%s: sshbuf_new failed", __func__);
2940+ if ((r = sshbuf_put_string(m, data->value, data->length)) != 0)
2941+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2942+
2943+ mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSIGN, m);
2944+ mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSIGN, m);
2945+
2946+ if ((r = sshbuf_get_u32(m, &major)) != 0 ||
2947+ (r = ssh_gssapi_get_buffer_desc(m, hash)) != 0)
2948+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2949+
2950+ sshbuf_free(m);
2951+
2952+ return (major);
2953+}
2954+
2955+int
2956+mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store)
2957+{
2958+ struct sshbuf *m;
2959+ int r, ok;
2960+
2961+ if ((m = sshbuf_new()) == NULL)
2962+ fatal("%s: sshbuf_new failed", __func__);
2963+
2964+ if ((r = sshbuf_put_cstring(m,
2965+ store->filename ? store->filename : "")) != 0 ||
2966+ (r = sshbuf_put_cstring(m,
2967+ store->envvar ? store->envvar : "")) != 0 ||
2968+ (r = sshbuf_put_cstring(m,
2969+ store->envval ? store->envval : "")) != 0)
2970+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2971+
2972+ mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUPCREDS, m);
2973+ mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUPCREDS, m);
2974+
2975+ if ((r = sshbuf_get_u32(m, &ok)) != 0)
2976+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
2977+
2978+ sshbuf_free(m);
2979+
2980+ return (ok);
2981+}
2982+
2983 #endif /* GSSAPI */
2984diff --git a/monitor_wrap.h b/monitor_wrap.h
2985index 0db38c206..75aef1c74 100644
2986--- a/monitor_wrap.h
2987+++ b/monitor_wrap.h
2988@@ -65,8 +65,10 @@ int mm_sshkey_verify(const struct sshkey *, const u_char *, size_t,
2989 OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
2990 OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *,
2991 gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *);
2992-int mm_ssh_gssapi_userok(char *user);
2993+int mm_ssh_gssapi_userok(char *user, struct passwd *, int kex);
2994 OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
2995+OM_uint32 mm_ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
2996+int mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *);
2997 #endif
2998
2999 #ifdef USE_PAM
3000diff --git a/readconf.c b/readconf.c
3001index 554efd7c9..57dae55d1 100644
3002--- a/readconf.c
3003+++ b/readconf.c
3004@@ -67,6 +67,7 @@
3005 #include "uidswap.h"
3006 #include "myproposal.h"
3007 #include "digest.h"
3008+#include "ssh-gss.h"
3009
3010 /* Format of the configuration file:
3011
3012@@ -160,6 +161,8 @@ typedef enum {
3013 oClearAllForwardings, oNoHostAuthenticationForLocalhost,
3014 oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
3015 oAddressFamily, oGssAuthentication, oGssDelegateCreds,
3016+ oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
3017+ oGssServerIdentity, oGssKexAlgorithms,
3018 oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
3019 oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
3020 oHashKnownHosts,
3021@@ -204,10 +207,22 @@ static struct {
3022 /* Sometimes-unsupported options */
3023 #if defined(GSSAPI)
3024 { "gssapiauthentication", oGssAuthentication },
3025+ { "gssapikeyexchange", oGssKeyEx },
3026 { "gssapidelegatecredentials", oGssDelegateCreds },
3027+ { "gssapitrustdns", oGssTrustDns },
3028+ { "gssapiclientidentity", oGssClientIdentity },
3029+ { "gssapiserveridentity", oGssServerIdentity },
3030+ { "gssapirenewalforcesrekey", oGssRenewalRekey },
3031+ { "gssapikexalgorithms", oGssKexAlgorithms },
3032 # else
3033 { "gssapiauthentication", oUnsupported },
3034+ { "gssapikeyexchange", oUnsupported },
3035 { "gssapidelegatecredentials", oUnsupported },
3036+ { "gssapitrustdns", oUnsupported },
3037+ { "gssapiclientidentity", oUnsupported },
3038+ { "gssapiserveridentity", oUnsupported },
3039+ { "gssapirenewalforcesrekey", oUnsupported },
3040+ { "gssapikexalgorithms", oUnsupported },
3041 #endif
3042 #ifdef ENABLE_PKCS11
3043 { "pkcs11provider", oPKCS11Provider },
3044@@ -1068,10 +1083,42 @@ parse_time:
3045 intptr = &options->gss_authentication;
3046 goto parse_flag;
3047
3048+ case oGssKeyEx:
3049+ intptr = &options->gss_keyex;
3050+ goto parse_flag;
3051+
3052 case oGssDelegateCreds:
3053 intptr = &options->gss_deleg_creds;
3054 goto parse_flag;
3055
3056+ case oGssTrustDns:
3057+ intptr = &options->gss_trust_dns;
3058+ goto parse_flag;
3059+
3060+ case oGssClientIdentity:
3061+ charptr = &options->gss_client_identity;
3062+ goto parse_string;
3063+
3064+ case oGssServerIdentity:
3065+ charptr = &options->gss_server_identity;
3066+ goto parse_string;
3067+
3068+ case oGssRenewalRekey:
3069+ intptr = &options->gss_renewal_rekey;
3070+ goto parse_flag;
3071+
3072+ case oGssKexAlgorithms:
3073+ arg = strdelim(&s);
3074+ if (!arg || *arg == '\0')
3075+ fatal("%.200s line %d: Missing argument.",
3076+ filename, linenum);
3077+ if (!kex_gss_names_valid(arg))
3078+ fatal("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
3079+ filename, linenum, arg ? arg : "<NONE>");
3080+ if (*activep && options->gss_kex_algorithms == NULL)
3081+ options->gss_kex_algorithms = xstrdup(arg);
3082+ break;
3083+
3084 case oBatchMode:
3085 intptr = &options->batch_mode;
3086 goto parse_flag;
3087@@ -1976,7 +2023,13 @@ initialize_options(Options * options)
3088 options->pubkey_authentication = -1;
3089 options->challenge_response_authentication = -1;
3090 options->gss_authentication = -1;
3091+ options->gss_keyex = -1;
3092 options->gss_deleg_creds = -1;
3093+ options->gss_trust_dns = -1;
3094+ options->gss_renewal_rekey = -1;
3095+ options->gss_client_identity = NULL;
3096+ options->gss_server_identity = NULL;
3097+ options->gss_kex_algorithms = NULL;
3098 options->password_authentication = -1;
3099 options->kbd_interactive_authentication = -1;
3100 options->kbd_interactive_devices = NULL;
3101@@ -2125,8 +2178,18 @@ fill_default_options(Options * options)
3102 options->challenge_response_authentication = 1;
3103 if (options->gss_authentication == -1)
3104 options->gss_authentication = 0;
3105+ if (options->gss_keyex == -1)
3106+ options->gss_keyex = 0;
3107 if (options->gss_deleg_creds == -1)
3108 options->gss_deleg_creds = 0;
3109+ if (options->gss_trust_dns == -1)
3110+ options->gss_trust_dns = 0;
3111+ if (options->gss_renewal_rekey == -1)
3112+ options->gss_renewal_rekey = 0;
3113+#ifdef GSSAPI
3114+ if (options->gss_kex_algorithms == NULL)
3115+ options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
3116+#endif
3117 if (options->password_authentication == -1)
3118 options->password_authentication = 1;
3119 if (options->kbd_interactive_authentication == -1)
3120@@ -2776,7 +2839,14 @@ dump_client_config(Options *o, const char *host)
3121 dump_cfg_fmtint(oGatewayPorts, o->fwd_opts.gateway_ports);
3122 #ifdef GSSAPI
3123 dump_cfg_fmtint(oGssAuthentication, o->gss_authentication);
3124+ dump_cfg_fmtint(oGssKeyEx, o->gss_keyex);
3125 dump_cfg_fmtint(oGssDelegateCreds, o->gss_deleg_creds);
3126+ dump_cfg_fmtint(oGssTrustDns, o->gss_trust_dns);
3127+ dump_cfg_fmtint(oGssRenewalRekey, o->gss_renewal_rekey);
3128+ dump_cfg_string(oGssClientIdentity, o->gss_client_identity);
3129+ dump_cfg_string(oGssServerIdentity, o->gss_server_identity);
3130+ dump_cfg_string(oGssKexAlgorithms, o->gss_kex_algorithms ?
3131+ o->gss_kex_algorithms : GSS_KEX_DEFAULT_KEX);
3132 #endif /* GSSAPI */
3133 dump_cfg_fmtint(oHashKnownHosts, o->hash_known_hosts);
3134 dump_cfg_fmtint(oHostbasedAuthentication, o->hostbased_authentication);
3135diff --git a/readconf.h b/readconf.h
3136index d6a15550d..3803eeddf 100644
3137--- a/readconf.h
3138+++ b/readconf.h
3139@@ -41,7 +41,13 @@ typedef struct {
3140 int challenge_response_authentication;
3141 /* Try S/Key or TIS, authentication. */
3142 int gss_authentication; /* Try GSS authentication */
3143+ int gss_keyex; /* Try GSS key exchange */
3144 int gss_deleg_creds; /* Delegate GSS credentials */
3145+ int gss_trust_dns; /* Trust DNS for GSS canonicalization */
3146+ int gss_renewal_rekey; /* Credential renewal forces rekey */
3147+ char *gss_client_identity; /* Principal to initiate GSSAPI with */
3148+ char *gss_server_identity; /* GSSAPI target principal */
3149+ char *gss_kex_algorithms; /* GSSAPI kex methods to be offered by client. */
3150 int password_authentication; /* Try password
3151 * authentication. */
3152 int kbd_interactive_authentication; /* Try keyboard-interactive auth. */
3153diff --git a/servconf.c b/servconf.c
3154index f08e37477..ded8f4a87 100644
3155--- a/servconf.c
3156+++ b/servconf.c
3157@@ -70,6 +70,7 @@
3158 #include "auth.h"
3159 #include "myproposal.h"
3160 #include "digest.h"
3161+#include "ssh-gss.h"
3162
3163 static void add_listen_addr(ServerOptions *, const char *,
3164 const char *, int);
3165@@ -134,8 +135,11 @@ initialize_server_options(ServerOptions *options)
3166 options->kerberos_ticket_cleanup = -1;
3167 options->kerberos_get_afs_token = -1;
3168 options->gss_authentication=-1;
3169+ options->gss_keyex = -1;
3170 options->gss_cleanup_creds = -1;
3171 options->gss_strict_acceptor = -1;
3172+ options->gss_store_rekey = -1;
3173+ options->gss_kex_algorithms = NULL;
3174 options->password_authentication = -1;
3175 options->kbd_interactive_authentication = -1;
3176 options->challenge_response_authentication = -1;
3177@@ -376,10 +380,18 @@ fill_default_server_options(ServerOptions *options)
3178 options->kerberos_get_afs_token = 0;
3179 if (options->gss_authentication == -1)
3180 options->gss_authentication = 0;
3181+ if (options->gss_keyex == -1)
3182+ options->gss_keyex = 0;
3183 if (options->gss_cleanup_creds == -1)
3184 options->gss_cleanup_creds = 1;
3185 if (options->gss_strict_acceptor == -1)
3186 options->gss_strict_acceptor = 1;
3187+ if (options->gss_store_rekey == -1)
3188+ options->gss_store_rekey = 0;
3189+#ifdef GSSAPI
3190+ if (options->gss_kex_algorithms == NULL)
3191+ options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
3192+#endif
3193 if (options->password_authentication == -1)
3194 options->password_authentication = 1;
3195 if (options->kbd_interactive_authentication == -1)
3196@@ -523,6 +535,7 @@ typedef enum {
3197 sHostKeyAlgorithms,
3198 sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
3199 sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
3200+ sGssKeyEx, sGssKexAlgorithms, sGssStoreRekey,
3201 sAcceptEnv, sSetEnv, sPermitTunnel,
3202 sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
3203 sUsePrivilegeSeparation, sAllowAgentForwarding,
3204@@ -600,12 +613,22 @@ static struct {
3205 #ifdef GSSAPI
3206 { "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
3207 { "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
3208+ { "gssapicleanupcreds", sGssCleanupCreds, SSHCFG_GLOBAL },
3209 { "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
3210+ { "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL },
3211+ { "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL },
3212+ { "gssapikexalgorithms", sGssKexAlgorithms, SSHCFG_GLOBAL },
3213 #else
3214 { "gssapiauthentication", sUnsupported, SSHCFG_ALL },
3215 { "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
3216+ { "gssapicleanupcreds", sUnsupported, SSHCFG_GLOBAL },
3217 { "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
3218+ { "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL },
3219+ { "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL },
3220+ { "gssapikexalgorithms", sUnsupported, SSHCFG_GLOBAL },
3221 #endif
3222+ { "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
3223+ { "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
3224 { "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
3225 { "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
3226 { "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL },
3227@@ -1557,6 +1580,10 @@ process_server_config_line_depth(ServerOptions *options, char *line,
3228 intptr = &options->gss_authentication;
3229 goto parse_flag;
3230
3231+ case sGssKeyEx:
3232+ intptr = &options->gss_keyex;
3233+ goto parse_flag;
3234+
3235 case sGssCleanupCreds:
3236 intptr = &options->gss_cleanup_creds;
3237 goto parse_flag;
3238@@ -1565,6 +1592,22 @@ process_server_config_line_depth(ServerOptions *options, char *line,
3239 intptr = &options->gss_strict_acceptor;
3240 goto parse_flag;
3241
3242+ case sGssStoreRekey:
3243+ intptr = &options->gss_store_rekey;
3244+ goto parse_flag;
3245+
3246+ case sGssKexAlgorithms:
3247+ arg = strdelim(&cp);
3248+ if (!arg || *arg == '\0')
3249+ fatal("%.200s line %d: Missing argument.",
3250+ filename, linenum);
3251+ if (!kex_gss_names_valid(arg))
3252+ fatal("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
3253+ filename, linenum, arg ? arg : "<NONE>");
3254+ if (*activep && options->gss_kex_algorithms == NULL)
3255+ options->gss_kex_algorithms = xstrdup(arg);
3256+ break;
3257+
3258 case sPasswordAuthentication:
3259 intptr = &options->password_authentication;
3260 goto parse_flag;
3261@@ -2808,6 +2851,10 @@ dump_config(ServerOptions *o)
3262 #ifdef GSSAPI
3263 dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
3264 dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
3265+ dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
3266+ dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
3267+ dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
3268+ dump_cfg_string(sGssKexAlgorithms, o->gss_kex_algorithms);
3269 #endif
3270 dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
3271 dump_cfg_fmtint(sKbdInteractiveAuthentication,
3272diff --git a/servconf.h b/servconf.h
3273index 1df8f3db8..f10908e5b 100644
3274--- a/servconf.h
3275+++ b/servconf.h
3276@@ -138,8 +138,11 @@ typedef struct {
3277 int kerberos_get_afs_token; /* If true, try to get AFS token if
3278 * authenticated with Kerberos. */
3279 int gss_authentication; /* If true, permit GSSAPI authentication */
3280+ int gss_keyex; /* If true, permit GSSAPI key exchange */
3281 int gss_cleanup_creds; /* If true, destroy cred cache on logout */
3282 int gss_strict_acceptor; /* If true, restrict the GSSAPI acceptor name */
3283+ int gss_store_rekey;
3284+ char *gss_kex_algorithms; /* GSSAPI kex methods to be offered by client. */
3285 int password_authentication; /* If true, permit password
3286 * authentication. */
3287 int kbd_interactive_authentication; /* If true, permit */
3288diff --git a/session.c b/session.c
3289index 27ca8a104..857f17b3c 100644
3290--- a/session.c
3291+++ b/session.c
3292@@ -2685,13 +2685,19 @@ do_cleanup(struct ssh *ssh, Authctxt *authctxt)
3293
3294 #ifdef KRB5
3295 if (options.kerberos_ticket_cleanup &&
3296- authctxt->krb5_ctx)
3297+ authctxt->krb5_ctx) {
3298+ temporarily_use_uid(authctxt->pw);
3299 krb5_cleanup_proc(authctxt);
3300+ restore_uid();
3301+ }
3302 #endif
3303
3304 #ifdef GSSAPI
3305- if (options.gss_cleanup_creds)
3306+ if (options.gss_cleanup_creds) {
3307+ temporarily_use_uid(authctxt->pw);
3308 ssh_gssapi_cleanup_creds();
3309+ restore_uid();
3310+ }
3311 #endif
3312
3313 /* remove agent socket */
3314diff --git a/ssh-gss.h b/ssh-gss.h
3315index 36180d07a..50d80bbca 100644
3316--- a/ssh-gss.h
3317+++ b/ssh-gss.h
3318@@ -1,6 +1,6 @@
3319 /* $OpenBSD: ssh-gss.h,v 1.14 2018/07/10 09:13:30 djm Exp $ */
3320 /*
3321- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
3322+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
3323 *
3324 * Redistribution and use in source and binary forms, with or without
3325 * modification, are permitted provided that the following conditions
3326@@ -61,10 +61,34 @@
3327
3328 #define SSH_GSS_OIDTYPE 0x06
3329
3330+#define SSH2_MSG_KEXGSS_INIT 30
3331+#define SSH2_MSG_KEXGSS_CONTINUE 31
3332+#define SSH2_MSG_KEXGSS_COMPLETE 32
3333+#define SSH2_MSG_KEXGSS_HOSTKEY 33
3334+#define SSH2_MSG_KEXGSS_ERROR 34
3335+#define SSH2_MSG_KEXGSS_GROUPREQ 40
3336+#define SSH2_MSG_KEXGSS_GROUP 41
3337+#define KEX_GSS_GRP1_SHA1_ID "gss-group1-sha1-"
3338+#define KEX_GSS_GRP14_SHA1_ID "gss-group14-sha1-"
3339+#define KEX_GSS_GRP14_SHA256_ID "gss-group14-sha256-"
3340+#define KEX_GSS_GRP16_SHA512_ID "gss-group16-sha512-"
3341+#define KEX_GSS_GEX_SHA1_ID "gss-gex-sha1-"
3342+#define KEX_GSS_NISTP256_SHA256_ID "gss-nistp256-sha256-"
3343+#define KEX_GSS_C25519_SHA256_ID "gss-curve25519-sha256-"
3344+
3345+#define GSS_KEX_DEFAULT_KEX \
3346+ KEX_GSS_GRP14_SHA256_ID "," \
3347+ KEX_GSS_GRP16_SHA512_ID "," \
3348+ KEX_GSS_NISTP256_SHA256_ID "," \
3349+ KEX_GSS_C25519_SHA256_ID "," \
3350+ KEX_GSS_GRP14_SHA1_ID "," \
3351+ KEX_GSS_GEX_SHA1_ID
3352+
3353 typedef struct {
3354 char *filename;
3355 char *envvar;
3356 char *envval;
3357+ struct passwd *owner;
3358 void *data;
3359 } ssh_gssapi_ccache;
3360
3361@@ -72,8 +96,11 @@ typedef struct {
3362 gss_buffer_desc displayname;
3363 gss_buffer_desc exportedname;
3364 gss_cred_id_t creds;
3365+ gss_name_t name;
3366 struct ssh_gssapi_mech_struct *mech;
3367 ssh_gssapi_ccache store;
3368+ int used;
3369+ int updated;
3370 } ssh_gssapi_client;
3371
3372 typedef struct ssh_gssapi_mech_struct {
3373@@ -84,6 +111,7 @@ typedef struct ssh_gssapi_mech_struct {
3374 int (*userok) (ssh_gssapi_client *, char *);
3375 int (*localname) (ssh_gssapi_client *, char **);
3376 void (*storecreds) (ssh_gssapi_client *);
3377+ int (*updatecreds) (ssh_gssapi_ccache *, ssh_gssapi_client *);
3378 } ssh_gssapi_mech;
3379
3380 typedef struct {
3381@@ -94,10 +122,11 @@ typedef struct {
3382 gss_OID oid; /* client */
3383 gss_cred_id_t creds; /* server */
3384 gss_name_t client; /* server */
3385- gss_cred_id_t client_creds; /* server */
3386+ gss_cred_id_t client_creds; /* both */
3387 } Gssctxt;
3388
3389 extern ssh_gssapi_mech *supported_mechs[];
3390+extern Gssctxt *gss_kex_context;
3391
3392 int ssh_gssapi_check_oid(Gssctxt *, void *, size_t);
3393 void ssh_gssapi_set_oid_data(Gssctxt *, void *, size_t);
3394@@ -109,6 +138,7 @@ OM_uint32 ssh_gssapi_test_oid_supported(OM_uint32 *, gss_OID, int *);
3395
3396 struct sshbuf;
3397 int ssh_gssapi_get_buffer_desc(struct sshbuf *, gss_buffer_desc *);
3398+int ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *, gss_buffer_desc *);
3399
3400 OM_uint32 ssh_gssapi_import_name(Gssctxt *, const char *);
3401 OM_uint32 ssh_gssapi_init_ctx(Gssctxt *, int,
3402@@ -123,17 +153,33 @@ void ssh_gssapi_delete_ctx(Gssctxt **);
3403 OM_uint32 ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
3404 void ssh_gssapi_buildmic(struct sshbuf *, const char *,
3405 const char *, const char *);
3406-int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *);
3407+int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *, const char *);
3408+OM_uint32 ssh_gssapi_client_identity(Gssctxt *, const char *);
3409+int ssh_gssapi_credentials_updated(Gssctxt *);
3410
3411 /* In the server */
3412+typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *,
3413+ const char *);
3414+char *ssh_gssapi_client_mechanisms(const char *, const char *, const char *);
3415+char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *,
3416+ const char *, const char *);
3417+gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int);
3418+int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *,
3419+ const char *);
3420 OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
3421-int ssh_gssapi_userok(char *name);
3422+int ssh_gssapi_userok(char *name, struct passwd *, int kex);
3423 OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
3424 void ssh_gssapi_do_child(char ***, u_int *);
3425 void ssh_gssapi_cleanup_creds(void);
3426 void ssh_gssapi_storecreds(void);
3427 const char *ssh_gssapi_displayname(void);
3428
3429+char *ssh_gssapi_server_mechanisms(void);
3430+int ssh_gssapi_oid_table_ok(void);
3431+
3432+int ssh_gssapi_update_creds(ssh_gssapi_ccache *store);
3433+void ssh_gssapi_rekey_creds(void);
3434+
3435 #endif /* GSSAPI */
3436
3437 #endif /* _SSH_GSS_H */
3438diff --git a/ssh.1 b/ssh.1
3439index 555317887..be8e964f0 100644
3440--- a/ssh.1
3441+++ b/ssh.1
3442@@ -506,7 +506,13 @@ For full details of the options listed below, and their possible values, see
3443 .It GatewayPorts
3444 .It GlobalKnownHostsFile
3445 .It GSSAPIAuthentication
3446+.It GSSAPIKeyExchange
3447+.It GSSAPIClientIdentity
3448 .It GSSAPIDelegateCredentials
3449+.It GSSAPIKexAlgorithms
3450+.It GSSAPIRenewalForcesRekey
3451+.It GSSAPIServerIdentity
3452+.It GSSAPITrustDns
3453 .It HashKnownHosts
3454 .It Host
3455 .It HostbasedAuthentication
3456@@ -582,6 +588,8 @@ flag),
3457 (supported message integrity codes),
3458 .Ar kex
3459 (key exchange algorithms),
3460+.Ar kex-gss
3461+(GSSAPI key exchange algorithms),
3462 .Ar key
3463 (key types),
3464 .Ar key-cert
3465diff --git a/ssh.c b/ssh.c
3466index f34ca0d71..bb98a7e2d 100644
3467--- a/ssh.c
3468+++ b/ssh.c
3469@@ -801,6 +801,8 @@ main(int ac, char **av)
3470 else if (strcmp(optarg, "kex") == 0 ||
3471 strcasecmp(optarg, "KexAlgorithms") == 0)
3472 cp = kex_alg_list('\n');
3473+ else if (strcmp(optarg, "kex-gss") == 0)
3474+ cp = kex_gss_alg_list('\n');
3475 else if (strcmp(optarg, "key") == 0)
3476 cp = sshkey_alg_list(0, 0, 0, '\n');
3477 else if (strcmp(optarg, "key-cert") == 0)
3478@@ -826,8 +828,8 @@ main(int ac, char **av)
3479 } else if (strcmp(optarg, "help") == 0) {
3480 cp = xstrdup(
3481 "cipher\ncipher-auth\ncompression\nkex\n"
3482- "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
3483- "protocol-version\nsig");
3484+ "kex-gss\nkey\nkey-cert\nkey-plain\n"
3485+ "key-sig\nmac\nprotocol-version\nsig");
3486 }
3487 if (cp == NULL)
3488 fatal("Unsupported query \"%s\"", optarg);
3489diff --git a/ssh_config b/ssh_config
3490index 842ea866c..52aae8692 100644
3491--- a/ssh_config
3492+++ b/ssh_config
3493@@ -24,6 +24,8 @@
3494 # HostbasedAuthentication no
3495 # GSSAPIAuthentication no
3496 # GSSAPIDelegateCredentials no
3497+# GSSAPIKeyExchange no
3498+# GSSAPITrustDNS no
3499 # BatchMode no
3500 # CheckHostIP yes
3501 # AddressFamily any
3502diff --git a/ssh_config.5 b/ssh_config.5
3503index 6be1f1aa2..bd86d000c 100644
3504--- a/ssh_config.5
3505+++ b/ssh_config.5
3506@@ -779,10 +779,67 @@ The default is
3507 Specifies whether user authentication based on GSSAPI is allowed.
3508 The default is
3509 .Cm no .
3510+.It Cm GSSAPIClientIdentity
3511+If set, specifies the GSSAPI client identity that ssh should use when
3512+connecting to the server. The default is unset, which means that the default
3513+identity will be used.
3514 .It Cm GSSAPIDelegateCredentials
3515 Forward (delegate) credentials to the server.
3516 The default is
3517 .Cm no .
3518+.It Cm GSSAPIKeyExchange
3519+Specifies whether key exchange based on GSSAPI may be used. When using
3520+GSSAPI key exchange the server need not have a host key.
3521+The default is
3522+.Dq no .
3523+.It Cm GSSAPIRenewalForcesRekey
3524+If set to
3525+.Dq yes
3526+then renewal of the client's GSSAPI credentials will force the rekeying of the
3527+ssh connection. With a compatible server, this will delegate the renewed
3528+credentials to a session on the server.
3529+.Pp
3530+Checks are made to ensure that credentials are only propagated when the new
3531+credentials match the old ones on the originating client and where the
3532+receiving server still has the old set in its cache.
3533+.Pp
3534+The default is
3535+.Dq no .
3536+.Pp
3537+For this to work
3538+.Cm GSSAPIKeyExchange
3539+needs to be enabled in the server and also used by the client.
3540+.It Cm GSSAPIServerIdentity
3541+If set, specifies the GSSAPI server identity that ssh should expect when
3542+connecting to the server. The default is unset, which means that the
3543+expected GSSAPI server identity will be determined from the target
3544+hostname.
3545+.It Cm GSSAPITrustDns
3546+Set to
3547+.Dq yes
3548+to indicate that the DNS is trusted to securely canonicalize
3549+the name of the host being connected to. If
3550+.Dq no ,
3551+the hostname entered on the
3552+command line will be passed untouched to the GSSAPI library.
3553+The default is
3554+.Dq no .
3555+.It Cm GSSAPIKexAlgorithms
3556+The list of key exchange algorithms that are offered for GSSAPI
3557+key exchange. Possible values are
3558+.Bd -literal -offset 3n
3559+gss-gex-sha1-,
3560+gss-group1-sha1-,
3561+gss-group14-sha1-,
3562+gss-group14-sha256-,
3563+gss-group16-sha512-,
3564+gss-nistp256-sha256-,
3565+gss-curve25519-sha256-
3566+.Ed
3567+.Pp
3568+The default is
3569+.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,gss-curve25519-sha256-,gss-gex-sha1-,gss-group14-sha1- .
3570+This option only applies to connections using GSSAPI.
3571 .It Cm HashKnownHosts
3572 Indicates that
3573 .Xr ssh 1
3574diff --git a/sshconnect2.c b/sshconnect2.c
3575index f64aae66a..c47fc31a6 100644
3576--- a/sshconnect2.c
3577+++ b/sshconnect2.c
3578@@ -80,8 +80,6 @@
3579 #endif
3580
3581 /* import */
3582-extern char *client_version_string;
3583-extern char *server_version_string;
3584 extern Options options;
3585
3586 /*
3587@@ -210,6 +208,11 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port)
3588 char *s, *all_key;
3589 int r, use_known_hosts_order = 0;
3590
3591+#if defined(GSSAPI) && defined(WITH_OPENSSL)
3592+ char *orig = NULL, *gss = NULL;
3593+ char *gss_host = NULL;
3594+#endif
3595+
3596 xxx_host = host;
3597 xxx_hostaddr = hostaddr;
3598
3599@@ -253,6 +256,41 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port)
3600 compat_pkalg_proposal(options.hostkeyalgorithms);
3601 }
3602
3603+#if defined(GSSAPI) && defined(WITH_OPENSSL)
3604+ if (options.gss_keyex) {
3605+ /* Add the GSSAPI mechanisms currently supported on this
3606+ * client to the key exchange algorithm proposal */
3607+ orig = myproposal[PROPOSAL_KEX_ALGS];
3608+
3609+ if (options.gss_server_identity) {
3610+ gss_host = xstrdup(options.gss_server_identity);
3611+ } else if (options.gss_trust_dns) {
3612+ gss_host = remote_hostname(ssh);
3613+ /* Fall back to specified host if we are using proxy command
3614+ * and can not use DNS on that socket */
3615+ if (strcmp(gss_host, "UNKNOWN") == 0) {
3616+ gss_host = xstrdup(host);
3617+ }
3618+ } else {
3619+ gss_host = xstrdup(host);
3620+ }
3621+
3622+ gss = ssh_gssapi_client_mechanisms(gss_host,
3623+ options.gss_client_identity, options.gss_kex_algorithms);
3624+ if (gss) {
3625+ debug("Offering GSSAPI proposal: %s", gss);
3626+ xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
3627+ "%s,%s", gss, orig);
3628+
3629+ /* If we've got GSSAPI algorithms, then we also support the
3630+ * 'null' hostkey, as a last resort */
3631+ orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
3632+ xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
3633+ "%s,null", orig);
3634+ }
3635+ }
3636+#endif
3637+
3638 if (options.rekey_limit || options.rekey_interval)
3639 ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
3640 options.rekey_interval);
3641@@ -271,16 +309,46 @@ ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port)
3642 # ifdef OPENSSL_HAS_ECC
3643 ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
3644 # endif
3645-#endif
3646+# ifdef GSSAPI
3647+ if (options.gss_keyex) {
3648+ ssh->kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
3649+ ssh->kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
3650+ ssh->kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_client;
3651+ ssh->kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_client;
3652+ ssh->kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_client;
3653+ ssh->kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_client;
3654+ ssh->kex->kex[KEX_GSS_C25519_SHA256] = kexgss_client;
3655+ }
3656+# endif
3657+#endif /* WITH_OPENSSL */
3658 ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
3659 ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client;
3660 ssh->kex->verify_host_key=&verify_host_key_callback;
3661
3662+#if defined(GSSAPI) && defined(WITH_OPENSSL)
3663+ if (options.gss_keyex) {
3664+ ssh->kex->gss_deleg_creds = options.gss_deleg_creds;
3665+ ssh->kex->gss_trust_dns = options.gss_trust_dns;
3666+ ssh->kex->gss_client = options.gss_client_identity;
3667+ ssh->kex->gss_host = gss_host;
3668+ }
3669+#endif
3670+
3671 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done);
3672
3673 /* remove ext-info from the KEX proposals for rekeying */
3674 myproposal[PROPOSAL_KEX_ALGS] =
3675 compat_kex_proposal(options.kex_algorithms);
3676+#if defined(GSSAPI) && defined(WITH_OPENSSL)
3677+ /* repair myproposal after it was crumpled by the */
3678+ /* ext-info removal above */
3679+ if (gss) {
3680+ orig = myproposal[PROPOSAL_KEX_ALGS];
3681+ xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
3682+ "%s,%s", gss, orig);
3683+ free(gss);
3684+ }
3685+#endif
3686 if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0)
3687 fatal("kex_prop2buf: %s", ssh_err(r));
3688
3689@@ -377,6 +445,7 @@ static int input_gssapi_response(int type, u_int32_t, struct ssh *);
3690 static int input_gssapi_token(int type, u_int32_t, struct ssh *);
3691 static int input_gssapi_error(int, u_int32_t, struct ssh *);
3692 static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
3693+static int userauth_gsskeyex(struct ssh *);
3694 #endif
3695
3696 void userauth(struct ssh *, char *);
3697@@ -393,6 +462,11 @@ static char *authmethods_get(void);
3698
3699 Authmethod authmethods[] = {
3700 #ifdef GSSAPI
3701+ {"gssapi-keyex",
3702+ userauth_gsskeyex,
3703+ NULL,
3704+ &options.gss_keyex,
3705+ NULL},
3706 {"gssapi-with-mic",
3707 userauth_gssapi,
3708 userauth_gssapi_cleanup,
3709@@ -763,12 +837,31 @@ userauth_gssapi(struct ssh *ssh)
3710 OM_uint32 min;
3711 int r, ok = 0;
3712 gss_OID mech = NULL;
3713+ char *gss_host;
3714+
3715+ if (options.gss_server_identity) {
3716+ gss_host = xstrdup(options.gss_server_identity);
3717+ } else if (options.gss_trust_dns) {
3718+ gss_host = remote_hostname(ssh);
3719+ /* Fall back to specified host if we are using proxy command
3720+ * and can not use DNS on that socket */
3721+ if (strcmp(gss_host, "UNKNOWN") == 0) {
3722+ gss_host = authctxt->host;
3723+ }
3724+ } else {
3725+ gss_host = xstrdup(authctxt->host);
3726+ }
3727
3728 /* Try one GSSAPI method at a time, rather than sending them all at
3729 * once. */
3730
3731 if (authctxt->gss_supported_mechs == NULL)
3732- gss_indicate_mechs(&min, &authctxt->gss_supported_mechs);
3733+ if (GSS_ERROR(gss_indicate_mechs(&min,
3734+ &authctxt->gss_supported_mechs))) {
3735+ authctxt->gss_supported_mechs = NULL;
3736+ free(gss_host);
3737+ return 0;
3738+ }
3739
3740 /* Check to see whether the mechanism is usable before we offer it */
3741 while (authctxt->mech_tried < authctxt->gss_supported_mechs->count &&
3742@@ -777,13 +870,15 @@ userauth_gssapi(struct ssh *ssh)
3743 elements[authctxt->mech_tried];
3744 /* My DER encoding requires length<128 */
3745 if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt,
3746- mech, authctxt->host)) {
3747+ mech, gss_host, options.gss_client_identity)) {
3748 ok = 1; /* Mechanism works */
3749 } else {
3750 authctxt->mech_tried++;
3751 }
3752 }
3753
3754+ free(gss_host);
3755+
3756 if (!ok || mech == NULL)
3757 return 0;
3758
3759@@ -1023,6 +1118,55 @@ input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh)
3760 free(lang);
3761 return r;
3762 }
3763+
3764+int
3765+userauth_gsskeyex(struct ssh *ssh)
3766+{
3767+ struct sshbuf *b = NULL;
3768+ Authctxt *authctxt = ssh->authctxt;
3769+ gss_buffer_desc gssbuf;
3770+ gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
3771+ OM_uint32 ms;
3772+ int r;
3773+
3774+ static int attempt = 0;
3775+ if (attempt++ >= 1)
3776+ return (0);
3777+
3778+ if (gss_kex_context == NULL) {
3779+ debug("No valid Key exchange context");
3780+ return (0);
3781+ }
3782+
3783+ if ((b = sshbuf_new()) == NULL)
3784+ fatal("%s: sshbuf_new failed", __func__);
3785+
3786+ ssh_gssapi_buildmic(b, authctxt->server_user, authctxt->service,
3787+ "gssapi-keyex");
3788+
3789+ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
3790+ fatal("%s: sshbuf_mutable_ptr failed", __func__);
3791+ gssbuf.length = sshbuf_len(b);
3792+
3793+ if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
3794+ sshbuf_free(b);
3795+ return (0);
3796+ }
3797+
3798+ if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
3799+ (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
3800+ (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
3801+ (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
3802+ (r = sshpkt_put_string(ssh, mic.value, mic.length)) != 0 ||
3803+ (r = sshpkt_send(ssh)) != 0)
3804+ fatal("%s: %s", __func__, ssh_err(r));
3805+
3806+ sshbuf_free(b);
3807+ gss_release_buffer(&ms, &mic);
3808+
3809+ return (1);
3810+}
3811+
3812 #endif /* GSSAPI */
3813
3814 static int
3815diff --git a/sshd.c b/sshd.c
3816index 8aa7f3df6..8c5d5822e 100644
3817--- a/sshd.c
3818+++ b/sshd.c
3819@@ -816,8 +816,8 @@ notify_hostkeys(struct ssh *ssh)
3820 }
3821 debug3("%s: sent %u hostkeys", __func__, nkeys);
3822 if (nkeys == 0)
3823- fatal("%s: no hostkeys", __func__);
3824- if ((r = sshpkt_send(ssh)) != 0)
3825+ debug3("%s: no hostkeys", __func__);
3826+ else if ((r = sshpkt_send(ssh)) != 0)
3827 sshpkt_fatal(ssh, r, "%s: send", __func__);
3828 sshbuf_free(buf);
3829 }
3830@@ -1901,7 +1901,8 @@ main(int ac, char **av)
3831 free(fp);
3832 }
3833 accumulate_host_timing_secret(cfg, NULL);
3834- if (!sensitive_data.have_ssh2_key) {
3835+ /* The GSSAPI key exchange can run without a host key */
3836+ if (!sensitive_data.have_ssh2_key && !options.gss_keyex) {
3837 logit("sshd: no hostkeys available -- exiting.");
3838 exit(1);
3839 }
3840@@ -2393,6 +2394,48 @@ do_ssh2_kex(struct ssh *ssh)
3841 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
3842 list_hostkey_types());
3843
3844+#if defined(GSSAPI) && defined(WITH_OPENSSL)
3845+ {
3846+ char *orig;
3847+ char *gss = NULL;
3848+ char *newstr = NULL;
3849+ orig = myproposal[PROPOSAL_KEX_ALGS];
3850+
3851+ /*
3852+ * If we don't have a host key, then there's no point advertising
3853+ * the other key exchange algorithms
3854+ */
3855+
3856+ if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0)
3857+ orig = NULL;
3858+
3859+ if (options.gss_keyex)
3860+ gss = ssh_gssapi_server_mechanisms();
3861+ else
3862+ gss = NULL;
3863+
3864+ if (gss && orig)
3865+ xasprintf(&newstr, "%s,%s", gss, orig);
3866+ else if (gss)
3867+ newstr = gss;
3868+ else if (orig)
3869+ newstr = orig;
3870+
3871+ /*
3872+ * If we've got GSSAPI mechanisms, then we've got the 'null' host
3873+ * key alg, but we can't tell people about it unless its the only
3874+ * host key algorithm we support
3875+ */
3876+ if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0)
3877+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null";
3878+
3879+ if (newstr)
3880+ myproposal[PROPOSAL_KEX_ALGS] = newstr;
3881+ else
3882+ fatal("No supported key exchange algorithms");
3883+ }
3884+#endif
3885+
3886 /* start key exchange */
3887 if ((r = kex_setup(ssh, myproposal)) != 0)
3888 fatal("kex_setup: %s", ssh_err(r));
3889@@ -2408,7 +2451,18 @@ do_ssh2_kex(struct ssh *ssh)
3890 # ifdef OPENSSL_HAS_ECC
3891 kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
3892 # endif
3893-#endif
3894+# ifdef GSSAPI
3895+ if (options.gss_keyex) {
3896+ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
3897+ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
3898+ kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
3899+ kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
3900+ kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
3901+ kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
3902+ kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
3903+ }
3904+# endif
3905+#endif /* WITH_OPENSSL */
3906 kex->kex[KEX_C25519_SHA256] = kex_gen_server;
3907 kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_server;
3908 kex->load_host_public_key=&get_hostkey_public_by_type;
3909diff --git a/sshd_config b/sshd_config
3910index 19b7c91a1..2c48105f8 100644
3911--- a/sshd_config
3912+++ b/sshd_config
3913@@ -69,6 +69,8 @@ AuthorizedKeysFile .ssh/authorized_keys
3914 # GSSAPI options
3915 #GSSAPIAuthentication no
3916 #GSSAPICleanupCredentials yes
3917+#GSSAPIStrictAcceptorCheck yes
3918+#GSSAPIKeyExchange no
3919
3920 # Set this to 'yes' to enable PAM authentication, account processing,
3921 # and session processing. If this is enabled, PAM authentication will
3922diff --git a/sshd_config.5 b/sshd_config.5
3923index 6fa421cae..eabbe9e73 100644
3924--- a/sshd_config.5
3925+++ b/sshd_config.5
3926@@ -644,6 +644,11 @@ Specifies whether to automatically destroy the user's credentials cache
3927 on logout.
3928 The default is
3929 .Cm yes .
3930+.It Cm GSSAPIKeyExchange
3931+Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange
3932+doesn't rely on ssh keys to verify host identity.
3933+The default is
3934+.Cm no .
3935 .It Cm GSSAPIStrictAcceptorCheck
3936 Determines whether to be strict about the identity of the GSSAPI acceptor
3937 a client authenticates against.
3938@@ -658,6 +663,31 @@ machine's default store.
3939 This facility is provided to assist with operation on multi homed machines.
3940 The default is
3941 .Cm yes .
3942+.It Cm GSSAPIStoreCredentialsOnRekey
3943+Controls whether the user's GSSAPI credentials should be updated following a
3944+successful connection rekeying. This option can be used to accepted renewed
3945+or updated credentials from a compatible client. The default is
3946+.Dq no .
3947+.Pp
3948+For this to work
3949+.Cm GSSAPIKeyExchange
3950+needs to be enabled in the server and also used by the client.
3951+.It Cm GSSAPIKexAlgorithms
3952+The list of key exchange algorithms that are accepted by GSSAPI
3953+key exchange. Possible values are
3954+.Bd -literal -offset 3n
3955+gss-gex-sha1-,
3956+gss-group1-sha1-,
3957+gss-group14-sha1-,
3958+gss-group14-sha256-,
3959+gss-group16-sha512-,
3960+gss-nistp256-sha256-,
3961+gss-curve25519-sha256-
3962+.Ed
3963+.Pp
3964+The default is
3965+.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,gss-curve25519-sha256-,gss-gex-sha1-,gss-group14-sha1- .
3966+This option only applies to connections using GSSAPI.
3967 .It Cm HostbasedAcceptedKeyTypes
3968 Specifies the key types that will be accepted for hostbased authentication
3969 as a list of comma-separated patterns.
3970diff --git a/sshkey.c b/sshkey.c
3971index ac451f1a8..b88282e19 100644
3972--- a/sshkey.c
3973+++ b/sshkey.c
3974@@ -156,6 +156,7 @@ static const struct keytype keytypes[] = {
3975 KEY_ECDSA_SK_CERT, NID_X9_62_prime256v1, 1, 0 },
3976 # endif /* OPENSSL_HAS_ECC */
3977 #endif /* WITH_OPENSSL */
3978+ { "null", "null", NULL, KEY_NULL, 0, 0, 0 },
3979 { NULL, NULL, NULL, -1, -1, 0, 0 }
3980 };
3981
3982@@ -257,7 +258,7 @@ sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
3983 const struct keytype *kt;
3984
3985 for (kt = keytypes; kt->type != -1; kt++) {
3986- if (kt->name == NULL)
3987+ if (kt->name == NULL || kt->type == KEY_NULL)
3988 continue;
3989 if (!include_sigonly && kt->sigonly)
3990 continue;
3991diff --git a/sshkey.h b/sshkey.h
3992index 2d8b62497..dc1c10597 100644
3993--- a/sshkey.h
3994+++ b/sshkey.h
3995@@ -69,6 +69,7 @@ enum sshkey_types {
3996 KEY_ECDSA_SK_CERT,
3997 KEY_ED25519_SK,
3998 KEY_ED25519_SK_CERT,
3999+ KEY_NULL,
4000 KEY_UNSPEC
4001 };
4002
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-02 11:38:32 +0000