From 95767262caa6692eff1e1565be1f5cb297949a89 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Mon, 7 Mar 2016 19:02:43 +0000 Subject: upstream commit refactor canohost.c: move functions that cache results closer to the places that use them (authn and session code). After this, no state is cached in canohost.c feedback and ok markus@ Upstream-ID: 5f2e4df88d4803fc8ec59ec53629105e23ce625e --- monitor_wrap.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'monitor_wrap.c') diff --git a/monitor_wrap.c b/monitor_wrap.c index c5db6df48..552004902 100644 --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: monitor_wrap.c,v 1.87 2016/01/14 16:17:40 markus Exp $ */ +/* $OpenBSD: monitor_wrap.c,v 1.88 2016/03/07 19:02:43 djm Exp $ */ /* * Copyright 2002 Niels Provos * Copyright 2002 Markus Friedl @@ -378,15 +378,15 @@ mm_user_key_allowed(struct passwd *pw, Key *key, int pubkey_auth_attempt) } int -mm_hostbased_key_allowed(struct passwd *pw, char *user, char *host, +mm_hostbased_key_allowed(struct passwd *pw, const char *user, const char *host, Key *key) { return (mm_key_allowed(MM_HOSTKEY, user, host, key, 0)); } int -mm_auth_rhosts_rsa_key_allowed(struct passwd *pw, char *user, - char *host, Key *key) +mm_auth_rhosts_rsa_key_allowed(struct passwd *pw, const char *user, + const char *host, Key *key) { int ret; @@ -397,8 +397,8 @@ mm_auth_rhosts_rsa_key_allowed(struct passwd *pw, char *user, } int -mm_key_allowed(enum mm_keytype type, char *user, char *host, Key *key, - int pubkey_auth_attempt) +mm_key_allowed(enum mm_keytype type, const char *user, const char *host, + Key *key, int pubkey_auth_attempt) { Buffer m; u_char *blob; -- cgit v1.2.3 From 01558b7b07af43da774d3a11a5c51fa9c310849d Mon Sep 17 00:00:00 2001 From: Darren Tucker Date: Mon, 18 Jul 2016 09:33:25 +1000 Subject: Handle PAM_MAXTRIES from modules. bz#2249: handle the case where PAM returns PAM_MAXTRIES by ceasing to offer password and keyboard-interative authentication methods. Should prevent "sshd ignoring max retries" warnings in the log. ok djm@ It probably won't trigger with keyboard-interactive in the default configuration because the retry counter is stored in module-private storage which goes away with the sshd PAM process (see bz#688). On the other hand, those cases probably won't log a warning either. --- auth-pam.c | 30 +++++++++++++++++++++++++++++- auth-pam.h | 2 ++ monitor.c | 5 +++++ monitor_wrap.c | 5 +++++ 4 files changed, 41 insertions(+), 1 deletion(-) (limited to 'monitor_wrap.c') diff --git a/auth-pam.c b/auth-pam.c index 465b5a702..1f13c181c 100644 --- a/auth-pam.c +++ b/auth-pam.c @@ -229,6 +229,7 @@ static int sshpam_authenticated = 0; static int sshpam_session_open = 0; static int sshpam_cred_established = 0; static int sshpam_account_status = -1; +static int sshpam_maxtries_reached = 0; static char **sshpam_env = NULL; static Authctxt *sshpam_authctxt = NULL; static const char *sshpam_password = NULL; @@ -450,6 +451,8 @@ sshpam_thread(void *ctxtp) if (sshpam_err != PAM_SUCCESS) goto auth_fail; sshpam_err = pam_authenticate(sshpam_handle, flags); + if (sshpam_err == PAM_MAXTRIES) + sshpam_set_maxtries_reached(1); if (sshpam_err != PAM_SUCCESS) goto auth_fail; @@ -501,6 +504,8 @@ sshpam_thread(void *ctxtp) /* XXX - can't do much about an error here */ if (sshpam_err == PAM_ACCT_EXPIRED) ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer); + else if (sshpam_maxtries_reached) + ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, &buffer); else ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer); buffer_free(&buffer); @@ -741,7 +746,11 @@ sshpam_query(void *ctx, char **name, char **info, free(msg); break; case PAM_ACCT_EXPIRED: - sshpam_account_status = 0; + case PAM_MAXTRIES: + if (type == PAM_ACCT_EXPIRED) + sshpam_account_status = 0; + if (type == PAM_MAXTRIES) + sshpam_set_maxtries_reached(1); /* FALLTHROUGH */ case PAM_AUTH_ERR: debug3("PAM: %s", pam_strerror(sshpam_handle, type)); @@ -1218,6 +1227,8 @@ sshpam_auth_passwd(Authctxt *authctxt, const char *password) sshpam_err = pam_authenticate(sshpam_handle, flags); sshpam_password = NULL; free(fake); + if (sshpam_err == PAM_MAXTRIES) + sshpam_set_maxtries_reached(1); if (sshpam_err == PAM_SUCCESS && authctxt->valid) { debug("PAM: password authentication accepted for %.100s", authctxt->user); @@ -1229,4 +1240,21 @@ sshpam_auth_passwd(Authctxt *authctxt, const char *password) return 0; } } + +int +sshpam_get_maxtries_reached(void) +{ + return sshpam_maxtries_reached; +} + +void +sshpam_set_maxtries_reached(int reached) +{ + if (reached == 0 || sshpam_maxtries_reached) + return; + sshpam_maxtries_reached = 1; + options.password_authentication = 0; + options.kbd_interactive_authentication = 0; + options.challenge_response_authentication = 0; +} #endif /* USE_PAM */ diff --git a/auth-pam.h b/auth-pam.h index a1a2b52d8..2e9a0c0a3 100644 --- a/auth-pam.h +++ b/auth-pam.h @@ -45,6 +45,8 @@ void free_pam_environment(char **); void sshpam_thread_cleanup(void); void sshpam_cleanup(void); int sshpam_auth_passwd(Authctxt *, const char *); +int sshpam_get_maxtries_reached(void); +void sshpam_set_maxtries_reached(int); int is_pam_session_open(void); #endif /* USE_PAM */ diff --git a/monitor.c b/monitor.c index 8b3c27a76..fbe965e7c 100644 --- a/monitor.c +++ b/monitor.c @@ -75,6 +75,7 @@ #include "cipher.h" #include "kex.h" #include "dh.h" +#include "auth-pam.h" #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ #undef TARGET_OS_MAC #include "zlib.h" @@ -920,6 +921,9 @@ mm_answer_authpassword(int sock, Buffer *m) buffer_clear(m); buffer_put_int(m, authenticated); +#ifdef USE_PAM + buffer_put_int(m, sshpam_get_maxtries_reached()); +#endif debug3("%s: sending result %d", __func__, authenticated); mm_request_send(sock, MONITOR_ANS_AUTHPASSWORD, m); @@ -1119,6 +1123,7 @@ mm_answer_pam_query(int sock, Buffer *m) free(name); buffer_put_cstring(m, info); free(info); + buffer_put_int(m, sshpam_get_maxtries_reached()); buffer_put_int(m, num); for (i = 0; i < num; ++i) { buffer_put_cstring(m, prompts[i]); diff --git a/monitor_wrap.c b/monitor_wrap.c index 552004902..99dc13b61 100644 --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -60,6 +60,7 @@ #include "packet.h" #include "mac.h" #include "log.h" +#include "auth-pam.h" #ifdef TARGET_OS_MAC /* XXX Broken krb5 headers on Mac */ #undef TARGET_OS_MAC #include "zlib.h" @@ -362,6 +363,9 @@ mm_auth_password(Authctxt *authctxt, char *password) mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUTHPASSWORD, &m); authenticated = buffer_get_int(&m); +#ifdef USE_PAM + sshpam_set_maxtries_reached(buffer_get_int(&m)); +#endif buffer_free(&m); @@ -644,6 +648,7 @@ mm_sshpam_query(void *ctx, char **name, char **info, debug3("%s: pam_query returned %d", __func__, ret); *name = buffer_get_string(&m, NULL); *info = buffer_get_string(&m, NULL); + sshpam_set_maxtries_reached(buffer_get_int(&m)); *num = buffer_get_int(&m); if (*num > PAM_MAX_NUM_MSG) fatal("%s: recieved %u PAM messages, expected <= %u", -- cgit v1.2.3 From eecddf8b72fcad83ccca43b1badb03782704f6b7 Mon Sep 17 00:00:00 2001 From: Simon Wilkinson Date: Sun, 9 Feb 2014 16:09:48 +0000 Subject: GSSAPI key exchange support This patch has been rejected upstream: "None of the OpenSSH developers are in favour of adding this, and this situation has not changed for several years. This is not a slight on Simon's patch, which is of fine quality, but just that a) we don't trust GSSAPI implementations that much and b) we don't like adding new KEX since they are pre-auth attack surface. This one is particularly scary, since it requires hooks out to typically root-owned system resources." However, quite a lot of people rely on this in Debian, and it's better to have it merged into the main openssh package rather than having separate -krb5 packages (as we used to have). It seems to have a generally good security history. Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242 Last-Updated: 2016-08-07 Patch-Name: gssapi.patch --- ChangeLog.gssapi | 113 +++++++++++++++++++ Makefile.in | 3 +- auth-krb5.c | 17 ++- auth.c | 96 +--------------- auth2-gss.c | 48 +++++++- auth2.c | 2 + canohost.c | 93 +++++++++++++++ canohost.h | 3 + clientloop.c | 15 ++- config.h.in | 6 + configure.ac | 24 ++++ gss-genr.c | 275 +++++++++++++++++++++++++++++++++++++++++++- gss-serv-krb5.c | 85 ++++++++++++-- gss-serv.c | 185 +++++++++++++++++++++++++++--- kex.c | 19 ++++ kex.h | 14 +++ kexgssc.c | 338 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ kexgsss.c | 295 ++++++++++++++++++++++++++++++++++++++++++++++++ monitor.c | 108 +++++++++++++++++- monitor.h | 3 + monitor_wrap.c | 47 +++++++- monitor_wrap.h | 4 +- readconf.c | 42 +++++++ readconf.h | 5 + servconf.c | 28 ++++- servconf.h | 2 + ssh-gss.h | 41 ++++++- ssh_config | 2 + ssh_config.5 | 32 ++++++ sshconnect2.c | 122 +++++++++++++++++++- sshd.c | 110 ++++++++++++++++++ sshd_config | 2 + sshd_config.5 | 10 ++ sshkey.c | 3 +- sshkey.h | 1 + 35 files changed, 2054 insertions(+), 139 deletions(-) create mode 100644 ChangeLog.gssapi create mode 100644 kexgssc.c create mode 100644 kexgsss.c (limited to 'monitor_wrap.c') diff --git a/ChangeLog.gssapi b/ChangeLog.gssapi new file mode 100644 index 000000000..f117a336a --- /dev/null +++ b/ChangeLog.gssapi @@ -0,0 +1,113 @@ +20110101 + - Finally update for OpenSSH 5.6p1 + - Add GSSAPIServerIdentity option from Jim Basney + +20100308 + - [ Makefile.in, key.c, key.h ] + Updates for OpenSSH 5.4p1 + - [ servconf.c ] + Include GSSAPI options in the sshd -T configuration dump, and flag + some older configuration options as being unsupported. Thanks to Colin + Watson. + - + +20100124 + - [ sshconnect2.c ] + Adapt to deal with additional element in Authmethod structure. Thanks to + Colin Watson + +20090615 + - [ gss-genr.c gss-serv.c kexgssc.c kexgsss.c monitor.c sshconnect2.c + sshd.c ] + Fix issues identified by Greg Hudson following a code review + Check return value of gss_indicate_mechs + Protect GSSAPI calls in monitor, so they can only be used if enabled + Check return values of bignum functions in key exchange + Use BN_clear_free to clear other side's DH value + Make ssh_gssapi_id_kex more robust + Only configure kex table pointers if GSSAPI is enabled + Don't leak mechanism list, or gss mechanism list + Cast data.length before printing + If serverkey isn't provided, use an empty string, rather than NULL + +20090201 + - [ gss-genr.c gss-serv.c kex.h kexgssc.c readconf.c readconf.h ssh-gss.h + ssh_config.5 sshconnet2.c ] + Add support for the GSSAPIClientIdentity option, which allows the user + to specify which GSSAPI identity to use to contact a given server + +20080404 + - [ gss-serv.c ] + Add code to actually implement GSSAPIStrictAcceptCheck, which had somehow + been omitted from a previous version of this patch. Reported by Borislav + Stoichkov + +20070317 + - [ gss-serv-krb5.c ] + Remove C99ism, where new_ccname was being declared in the middle of a + function + +20061220 + - [ servconf.c ] + Make default for GSSAPIStrictAcceptorCheck be Yes, to match previous, and + documented, behaviour. Reported by Dan Watson. + +20060910 + - [ gss-genr.c kexgssc.c kexgsss.c kex.h monitor.c sshconnect2.c sshd.c + ssh-gss.h ] + add support for gss-group14-sha1 key exchange mechanisms + - [ gss-serv.c servconf.c servconf.h sshd_config sshd_config.5 ] + Add GSSAPIStrictAcceptorCheck option to allow the disabling of + acceptor principal checking on multi-homed machines. + + - [ sshd_config ssh_config ] + Add settings for GSSAPIKeyExchange and GSSAPITrustDNS to the sample + configuration files + - [ kexgss.c kegsss.c sshconnect2.c sshd.c ] + Code cleanup. Replace strlen/xmalloc/snprintf sequences with xasprintf() + Limit length of error messages displayed by client + +20060909 + - [ gss-genr.c gss-serv.c ] + move ssh_gssapi_acquire_cred() and ssh_gssapi_server_ctx to be server + only, where they belong + + +20060829 + - [ gss-serv-krb5.c ] + Fix CCAPI credentials cache name when creating KRB5CCNAME environment + variable + +20060828 + - [ gss-genr.c ] + Avoid Heimdal context freeing problem + + +20060818 + - [ gss-genr.c ssh-gss.h sshconnect2.c ] + Make sure that SPENGO is disabled + + +20060421 + - [ gssgenr.c, sshconnect2.c ] + a few type changes (signed versus unsigned, int versus size_t) to + fix compiler errors/warnings + (from jbasney AT ncsa.uiuc.edu) + - [ kexgssc.c, sshconnect2.c ] + fix uninitialized variable warnings + (from jbasney AT ncsa.uiuc.edu) + - [ gssgenr.c ] + pass oid to gss_display_status (helpful when using GSSAPI mechglue) + (from jbasney AT ncsa.uiuc.edu) + + - [ gss-serv-krb5.c ] + #ifdef HAVE_GSSAPI_KRB5 should be #ifdef HAVE_GSSAPI_KRB5_H + (from jbasney AT ncsa.uiuc.edu) + + - [ readconf.c, readconf.h, ssh_config.5, sshconnect2.c + add client-side GssapiKeyExchange option + (from jbasney AT ncsa.uiuc.edu) + - [ sshconnect2.c ] + add support for GssapiTrustDns option for gssapi-with-mic + (from jbasney AT ncsa.uiuc.edu) + diff --git a/Makefile.in b/Makefile.in index 12991cd9f..51817dfe0 100644 --- a/Makefile.in +++ b/Makefile.in @@ -92,6 +92,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \ kex.o kexdh.o kexgex.o kexecdh.o kexc25519.o \ kexdhc.o kexgexc.o kexecdhc.o kexc25519c.o \ kexdhs.o kexgexs.o kexecdhs.o kexc25519s.o \ + kexgssc.o \ platform-pledge.o platform-tracing.o SSHOBJS= ssh.o readconf.o clientloop.o sshtty.o \ @@ -105,7 +106,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \ auth-skey.o auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \ auth2-none.o auth2-passwd.o auth2-pubkey.o \ monitor_mm.o monitor.o monitor_wrap.o auth-krb5.o \ - auth2-gss.o gss-serv.o gss-serv-krb5.o \ + auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o \ loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \ sftp-server.o sftp-common.o \ sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \ diff --git a/auth-krb5.c b/auth-krb5.c index a5a81ed2e..38e7fee21 100644 --- a/auth-krb5.c +++ b/auth-krb5.c @@ -182,8 +182,13 @@ auth_krb5_password(Authctxt *authctxt, const char *password) len = strlen(authctxt->krb5_ticket_file) + 6; authctxt->krb5_ccname = xmalloc(len); +#ifdef USE_CCAPI + snprintf(authctxt->krb5_ccname, len, "API:%s", + authctxt->krb5_ticket_file); +#else snprintf(authctxt->krb5_ccname, len, "FILE:%s", authctxt->krb5_ticket_file); +#endif #ifdef USE_PAM if (options.use_pam) @@ -240,15 +245,22 @@ krb5_cleanup_proc(Authctxt *authctxt) #ifndef HEIMDAL krb5_error_code ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { - int tmpfd, ret, oerrno; + int ret, oerrno; char ccname[40]; mode_t old_umask; +#ifdef USE_CCAPI + char cctemplate[] = "API:krb5cc_%d"; +#else + char cctemplate[] = "FILE:/tmp/krb5cc_%d_XXXXXXXXXX"; + int tmpfd; +#endif ret = snprintf(ccname, sizeof(ccname), - "FILE:/tmp/krb5cc_%d_XXXXXXXXXX", geteuid()); + cctemplate, geteuid()); if (ret < 0 || (size_t)ret >= sizeof(ccname)) return ENOMEM; +#ifndef USE_CCAPI old_umask = umask(0177); tmpfd = mkstemp(ccname + strlen("FILE:")); oerrno = errno; @@ -265,6 +277,7 @@ ssh_krb5_cc_gen(krb5_context ctx, krb5_ccache *ccache) { return oerrno; } close(tmpfd); +#endif return (krb5_cc_resolve(ctx, ccname, ccache)); } diff --git a/auth.c b/auth.c index 24527dd7c..f56dcc6cf 100644 --- a/auth.c +++ b/auth.c @@ -363,7 +363,8 @@ auth_root_allowed(const char *method) case PERMIT_NO_PASSWD: if (strcmp(method, "publickey") == 0 || strcmp(method, "hostbased") == 0 || - strcmp(method, "gssapi-with-mic") == 0) + strcmp(method, "gssapi-with-mic") == 0 || + strcmp(method, "gssapi-keyex") == 0) return 1; break; case PERMIT_FORCED_ONLY: @@ -785,99 +786,6 @@ fakepw(void) return (&fake); } -/* - * Returns the remote DNS hostname as a string. The returned string must not - * be freed. NB. this will usually trigger a DNS query the first time it is - * called. - * This function does additional checks on the hostname to mitigate some - * attacks on legacy rhosts-style authentication. - * XXX is RhostsRSAAuthentication vulnerable to these? - * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) - */ - -static char * -remote_hostname(struct ssh *ssh) -{ - struct sockaddr_storage from; - socklen_t fromlen; - struct addrinfo hints, *ai, *aitop; - char name[NI_MAXHOST], ntop2[NI_MAXHOST]; - const char *ntop = ssh_remote_ipaddr(ssh); - - /* Get IP address of client. */ - fromlen = sizeof(from); - memset(&from, 0, sizeof(from)); - if (getpeername(ssh_packet_get_connection_in(ssh), - (struct sockaddr *)&from, &fromlen) < 0) { - debug("getpeername failed: %.100s", strerror(errno)); - return strdup(ntop); - } - - ipv64_normalise_mapped(&from, &fromlen); - if (from.ss_family == AF_INET6) - fromlen = sizeof(struct sockaddr_in6); - - debug3("Trying to reverse map address %.100s.", ntop); - /* Map the IP address to a host name. */ - if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), - NULL, 0, NI_NAMEREQD) != 0) { - /* Host name not found. Use ip address. */ - return strdup(ntop); - } - - /* - * if reverse lookup result looks like a numeric hostname, - * someone is trying to trick us by PTR record like following: - * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 - */ - memset(&hints, 0, sizeof(hints)); - hints.ai_socktype = SOCK_DGRAM; /*dummy*/ - hints.ai_flags = AI_NUMERICHOST; - if (getaddrinfo(name, NULL, &hints, &ai) == 0) { - logit("Nasty PTR record \"%s\" is set up for %s, ignoring", - name, ntop); - freeaddrinfo(ai); - return strdup(ntop); - } - - /* Names are stored in lowercase. */ - lowercase(name); - - /* - * Map it back to an IP address and check that the given - * address actually is an address of this host. This is - * necessary because anyone with access to a name server can - * define arbitrary names for an IP address. Mapping from - * name to IP address can be trusted better (but can still be - * fooled if the intruder has access to the name server of - * the domain). - */ - memset(&hints, 0, sizeof(hints)); - hints.ai_family = from.ss_family; - hints.ai_socktype = SOCK_STREAM; - if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { - logit("reverse mapping checking getaddrinfo for %.700s " - "[%s] failed.", name, ntop); - return strdup(ntop); - } - /* Look for the address from the list of addresses. */ - for (ai = aitop; ai; ai = ai->ai_next) { - if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, - sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && - (strcmp(ntop, ntop2) == 0)) - break; - } - freeaddrinfo(aitop); - /* If we reached the end of the list, the address was not there. */ - if (ai == NULL) { - /* Address not found for the host name. */ - logit("Address %.100s maps to %.600s, but this does not " - "map back to the address.", ntop, name); - return strdup(ntop); - } - return strdup(name); -} - /* * Return the canonical name of the host in the other side of the current * connection. The host name is cached, so it is efficient to call this diff --git a/auth2-gss.c b/auth2-gss.c index 1ca835773..3b5036dfd 100644 --- a/auth2-gss.c +++ b/auth2-gss.c @@ -1,7 +1,7 @@ /* $OpenBSD: auth2-gss.c,v 1.22 2015/01/19 20:07:45 markus Exp $ */ /* - * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -53,6 +53,40 @@ static int input_gssapi_mic(int type, u_int32_t plen, void *ctxt); static int input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt); static int input_gssapi_errtok(int, u_int32_t, void *); +/* + * The 'gssapi_keyex' userauth mechanism. + */ +static int +userauth_gsskeyex(Authctxt *authctxt) +{ + int authenticated = 0; + Buffer b; + gss_buffer_desc mic, gssbuf; + u_int len; + + mic.value = packet_get_string(&len); + mic.length = len; + + packet_check_eom(); + + ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service, + "gssapi-keyex"); + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + /* gss_kex_context is NULL with privsep, so we can't check it here */ + if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context, + &gssbuf, &mic)))) + authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user, + authctxt->pw)); + + buffer_free(&b); + free(mic.value); + + return (authenticated); +} + /* * We only support those mechanisms that we know about (ie ones that we know * how to check local user kuserok and the like) @@ -238,7 +272,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt) packet_check_eom(); - authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user)); + authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user, + authctxt->pw)); authctxt->postponed = 0; dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); @@ -274,7 +309,8 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt) gssbuf.length = buffer_len(&b); if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic)))) - authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user)); + authenticated = + PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw)); else logit("GSSAPI MIC check failed"); @@ -290,6 +326,12 @@ input_gssapi_mic(int type, u_int32_t plen, void *ctxt) return 0; } +Authmethod method_gsskeyex = { + "gssapi-keyex", + userauth_gsskeyex, + &options.gss_authentication +}; + Authmethod method_gssapi = { "gssapi-with-mic", userauth_gssapi, diff --git a/auth2.c b/auth2.c index 9108b8612..ce0d37601 100644 --- a/auth2.c +++ b/auth2.c @@ -70,6 +70,7 @@ extern Authmethod method_passwd; extern Authmethod method_kbdint; extern Authmethod method_hostbased; #ifdef GSSAPI +extern Authmethod method_gsskeyex; extern Authmethod method_gssapi; #endif @@ -77,6 +78,7 @@ Authmethod *authmethods[] = { &method_none, &method_pubkey, #ifdef GSSAPI + &method_gsskeyex, &method_gssapi, #endif &method_passwd, diff --git a/canohost.c b/canohost.c index f71a08568..404731d24 100644 --- a/canohost.c +++ b/canohost.c @@ -35,6 +35,99 @@ #include "canohost.h" #include "misc.h" +/* + * Returns the remote DNS hostname as a string. The returned string must not + * be freed. NB. this will usually trigger a DNS query the first time it is + * called. + * This function does additional checks on the hostname to mitigate some + * attacks on legacy rhosts-style authentication. + * XXX is RhostsRSAAuthentication vulnerable to these? + * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?) + */ + +char * +remote_hostname(struct ssh *ssh) +{ + struct sockaddr_storage from; + socklen_t fromlen; + struct addrinfo hints, *ai, *aitop; + char name[NI_MAXHOST], ntop2[NI_MAXHOST]; + const char *ntop = ssh_remote_ipaddr(ssh); + + /* Get IP address of client. */ + fromlen = sizeof(from); + memset(&from, 0, sizeof(from)); + if (getpeername(ssh_packet_get_connection_in(ssh), + (struct sockaddr *)&from, &fromlen) < 0) { + debug("getpeername failed: %.100s", strerror(errno)); + return strdup(ntop); + } + + ipv64_normalise_mapped(&from, &fromlen); + if (from.ss_family == AF_INET6) + fromlen = sizeof(struct sockaddr_in6); + + debug3("Trying to reverse map address %.100s.", ntop); + /* Map the IP address to a host name. */ + if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), + NULL, 0, NI_NAMEREQD) != 0) { + /* Host name not found. Use ip address. */ + return strdup(ntop); + } + + /* + * if reverse lookup result looks like a numeric hostname, + * someone is trying to trick us by PTR record like following: + * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_socktype = SOCK_DGRAM; /*dummy*/ + hints.ai_flags = AI_NUMERICHOST; + if (getaddrinfo(name, NULL, &hints, &ai) == 0) { + logit("Nasty PTR record \"%s\" is set up for %s, ignoring", + name, ntop); + freeaddrinfo(ai); + return strdup(ntop); + } + + /* Names are stored in lowercase. */ + lowercase(name); + + /* + * Map it back to an IP address and check that the given + * address actually is an address of this host. This is + * necessary because anyone with access to a name server can + * define arbitrary names for an IP address. Mapping from + * name to IP address can be trusted better (but can still be + * fooled if the intruder has access to the name server of + * the domain). + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_family = from.ss_family; + hints.ai_socktype = SOCK_STREAM; + if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { + logit("reverse mapping checking getaddrinfo for %.700s " + "[%s] failed.", name, ntop); + return strdup(ntop); + } + /* Look for the address from the list of addresses. */ + for (ai = aitop; ai; ai = ai->ai_next) { + if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, + sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && + (strcmp(ntop, ntop2) == 0)) + break; + } + freeaddrinfo(aitop); + /* If we reached the end of the list, the address was not there. */ + if (ai == NULL) { + /* Address not found for the host name. */ + logit("Address %.100s maps to %.600s, but this does not " + "map back to the address.", ntop, name); + return strdup(ntop); + } + return strdup(name); +} + void ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len) { diff --git a/canohost.h b/canohost.h index 26d62855a..0cadc9f18 100644 --- a/canohost.h +++ b/canohost.h @@ -15,6 +15,9 @@ #ifndef _CANOHOST_H #define _CANOHOST_H +struct ssh; + +char *remote_hostname(struct ssh *); char *get_peer_ipaddr(int); int get_peer_port(int); char *get_local_ipaddr(int); diff --git a/clientloop.c b/clientloop.c index 2c44f5d19..421241f74 100644 --- a/clientloop.c +++ b/clientloop.c @@ -114,6 +114,10 @@ #include "ssherr.h" #include "hostfile.h" +#ifdef GSSAPI +#include "ssh-gss.h" +#endif + /* import options */ extern Options options; @@ -1666,9 +1670,18 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) break; /* Do channel operations unless rekeying in progress. */ - if (!ssh_packet_is_rekeying(active_state)) + if (!ssh_packet_is_rekeying(active_state)) { channel_after_select(readset, writeset); +#ifdef GSSAPI + if (options.gss_renewal_rekey && + ssh_gssapi_credentials_updated(NULL)) { + debug("credentials updated - forcing rekey"); + need_rekeying = 1; + } +#endif + } + /* Buffer input from the connection. */ client_process_net_input(readset); diff --git a/config.h.in b/config.h.in index 39d018f4c..d7caf9aa4 100644 --- a/config.h.in +++ b/config.h.in @@ -1668,6 +1668,9 @@ /* Use btmp to log bad logins */ #undef USE_BTMP +/* platform uses an in-memory credentials cache */ +#undef USE_CCAPI + /* Use libedit for sftp */ #undef USE_LIBEDIT @@ -1683,6 +1686,9 @@ /* Use PIPES instead of a socketpair() */ #undef USE_PIPES +/* platform has the Security Authorization Session API */ +#undef USE_SECURITY_SESSION_API + /* Define if you have Solaris privileges */ #undef USE_SOLARIS_PRIVS diff --git a/configure.ac b/configure.ac index 373d21b34..894ec3b7b 100644 --- a/configure.ac +++ b/configure.ac @@ -632,6 +632,30 @@ main() { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16)) [Use tunnel device compatibility to OpenBSD]) AC_DEFINE([SSH_TUN_PREPEND_AF], [1], [Prepend the address family to IP tunnel traffic]) + AC_MSG_CHECKING([if we have the Security Authorization Session API]) + AC_TRY_COMPILE([#include ], + [SessionCreate(0, 0);], + [ac_cv_use_security_session_api="yes" + AC_DEFINE([USE_SECURITY_SESSION_API], [1], + [platform has the Security Authorization Session API]) + LIBS="$LIBS -framework Security" + AC_MSG_RESULT([yes])], + [ac_cv_use_security_session_api="no" + AC_MSG_RESULT([no])]) + AC_MSG_CHECKING([if we have an in-memory credentials cache]) + AC_TRY_COMPILE( + [#include ], + [cc_context_t c; + (void) cc_initialize (&c, 0, NULL, NULL);], + [AC_DEFINE([USE_CCAPI], [1], + [platform uses an in-memory credentials cache]) + LIBS="$LIBS -framework Security" + AC_MSG_RESULT([yes]) + if test "x$ac_cv_use_security_session_api" = "xno"; then + AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***]) + fi], + [AC_MSG_RESULT([no])] + ) m4_pattern_allow([AU_IPv]) AC_CHECK_DECL([AU_IPv4], [], AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records]) diff --git a/gss-genr.c b/gss-genr.c index d617d600a..b4eca3feb 100644 --- a/gss-genr.c +++ b/gss-genr.c @@ -1,7 +1,7 @@ /* $OpenBSD: gss-genr.c,v 1.23 2015/01/20 23:14:00 deraadt Exp $ */ /* - * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -41,12 +41,167 @@ #include "buffer.h" #include "log.h" #include "ssh2.h" +#include "cipher.h" +#include "key.h" +#include "kex.h" +#include #include "ssh-gss.h" extern u_char *session_id2; extern u_int session_id2_len; +typedef struct { + char *encoded; + gss_OID oid; +} ssh_gss_kex_mapping; + +/* + * XXX - It would be nice to find a more elegant way of handling the + * XXX passing of the key exchange context to the userauth routines + */ + +Gssctxt *gss_kex_context = NULL; + +static ssh_gss_kex_mapping *gss_enc2oid = NULL; + +int +ssh_gssapi_oid_table_ok(void) { + return (gss_enc2oid != NULL); +} + +/* + * Return a list of the gss-group1-sha1 mechanisms supported by this program + * + * We test mechanisms to ensure that we can use them, to avoid starting + * a key exchange with a bad mechanism + */ + +char * +ssh_gssapi_client_mechanisms(const char *host, const char *client) { + gss_OID_set gss_supported; + OM_uint32 min_status; + + if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported))) + return NULL; + + return(ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism, + host, client)); +} + +char * +ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check, + const char *host, const char *client) { + Buffer buf; + size_t i; + int oidpos, enclen; + char *mechs, *encoded; + u_char digest[EVP_MAX_MD_SIZE]; + char deroid[2]; + const EVP_MD *evp_md = EVP_md5(); + EVP_MD_CTX md; + + if (gss_enc2oid != NULL) { + for (i = 0; gss_enc2oid[i].encoded != NULL; i++) + free(gss_enc2oid[i].encoded); + free(gss_enc2oid); + } + + gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) * + (gss_supported->count + 1)); + + buffer_init(&buf); + + oidpos = 0; + for (i = 0; i < gss_supported->count; i++) { + if (gss_supported->elements[i].length < 128 && + (*check)(NULL, &(gss_supported->elements[i]), host, client)) { + + deroid[0] = SSH_GSS_OIDTYPE; + deroid[1] = gss_supported->elements[i].length; + + EVP_DigestInit(&md, evp_md); + EVP_DigestUpdate(&md, deroid, 2); + EVP_DigestUpdate(&md, + gss_supported->elements[i].elements, + gss_supported->elements[i].length); + EVP_DigestFinal(&md, digest, NULL); + + encoded = xmalloc(EVP_MD_size(evp_md) * 2); + enclen = __b64_ntop(digest, EVP_MD_size(evp_md), + encoded, EVP_MD_size(evp_md) * 2); + + if (oidpos != 0) + buffer_put_char(&buf, ','); + + buffer_append(&buf, KEX_GSS_GEX_SHA1_ID, + sizeof(KEX_GSS_GEX_SHA1_ID) - 1); + buffer_append(&buf, encoded, enclen); + buffer_put_char(&buf, ','); + buffer_append(&buf, KEX_GSS_GRP1_SHA1_ID, + sizeof(KEX_GSS_GRP1_SHA1_ID) - 1); + buffer_append(&buf, encoded, enclen); + buffer_put_char(&buf, ','); + buffer_append(&buf, KEX_GSS_GRP14_SHA1_ID, + sizeof(KEX_GSS_GRP14_SHA1_ID) - 1); + buffer_append(&buf, encoded, enclen); + + gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]); + gss_enc2oid[oidpos].encoded = encoded; + oidpos++; + } + } + gss_enc2oid[oidpos].oid = NULL; + gss_enc2oid[oidpos].encoded = NULL; + + buffer_put_char(&buf, '\0'); + + mechs = xmalloc(buffer_len(&buf)); + buffer_get(&buf, mechs, buffer_len(&buf)); + buffer_free(&buf); + + if (strlen(mechs) == 0) { + free(mechs); + mechs = NULL; + } + + return (mechs); +} + +gss_OID +ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) { + int i = 0; + + switch (kex_type) { + case KEX_GSS_GRP1_SHA1: + if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID)) + return GSS_C_NO_OID; + name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1; + break; + case KEX_GSS_GRP14_SHA1: + if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID)) + return GSS_C_NO_OID; + name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1; + break; + case KEX_GSS_GEX_SHA1: + if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID)) + return GSS_C_NO_OID; + name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1; + break; + default: + return GSS_C_NO_OID; + } + + while (gss_enc2oid[i].encoded != NULL && + strcmp(name, gss_enc2oid[i].encoded) != 0) + i++; + + if (gss_enc2oid[i].oid != NULL && ctx != NULL) + ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid); + + return gss_enc2oid[i].oid; +} + /* Check that the OID in a data stream matches that in the context */ int ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len) @@ -199,7 +354,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok, } ctx->major = gss_init_sec_context(&ctx->minor, - GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid, + ctx->client_creds, &ctx->context, ctx->name, ctx->oid, GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag, 0, NULL, recv_tok, NULL, send_tok, flags, NULL); @@ -228,9 +383,43 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host) return (ctx->major); } +OM_uint32 +ssh_gssapi_client_identity(Gssctxt *ctx, const char *name) +{ + gss_buffer_desc gssbuf; + gss_name_t gssname; + OM_uint32 status; + gss_OID_set oidset; + + gssbuf.value = (void *) name; + gssbuf.length = strlen(gssbuf.value); + + gss_create_empty_oid_set(&status, &oidset); + gss_add_oid_set_member(&status, ctx->oid, &oidset); + + ctx->major = gss_import_name(&ctx->minor, &gssbuf, + GSS_C_NT_USER_NAME, &gssname); + + if (!ctx->major) + ctx->major = gss_acquire_cred(&ctx->minor, + gssname, 0, oidset, GSS_C_INITIATE, + &ctx->client_creds, NULL, NULL); + + gss_release_name(&status, &gssname); + gss_release_oid_set(&status, &oidset); + + if (ctx->major) + ssh_gssapi_error(ctx); + + return(ctx->major); +} + OM_uint32 ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) { + if (ctx == NULL) + return -1; + if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context, GSS_C_QOP_DEFAULT, buffer, hash))) ssh_gssapi_error(ctx); @@ -238,6 +427,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash) return (ctx->major); } +/* Priviledged when used by server */ +OM_uint32 +ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic) +{ + if (ctx == NULL) + return -1; + + ctx->major = gss_verify_mic(&ctx->minor, ctx->context, + gssbuf, gssmic, NULL); + + return (ctx->major); +} + void ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, const char *context) @@ -251,11 +453,16 @@ ssh_gssapi_buildmic(Buffer *b, const char *user, const char *service, } int -ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host) +ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host, + const char *client) { gss_buffer_desc token = GSS_C_EMPTY_BUFFER; OM_uint32 major, minor; gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"}; + Gssctxt *intctx = NULL; + + if (ctx == NULL) + ctx = &intctx; /* RFC 4462 says we MUST NOT do SPNEGO */ if (oid->length == spnego_oid.length && @@ -265,6 +472,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host) ssh_gssapi_build_ctx(ctx); ssh_gssapi_set_oid(*ctx, oid); major = ssh_gssapi_import_name(*ctx, host); + + if (!GSS_ERROR(major) && client) + major = ssh_gssapi_client_identity(*ctx, client); + if (!GSS_ERROR(major)) { major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token, NULL); @@ -274,10 +485,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host) GSS_C_NO_BUFFER); } - if (GSS_ERROR(major)) + if (GSS_ERROR(major) || intctx != NULL) ssh_gssapi_delete_ctx(ctx); return (!GSS_ERROR(major)); } +int +ssh_gssapi_credentials_updated(Gssctxt *ctxt) { + static gss_name_t saved_name = GSS_C_NO_NAME; + static OM_uint32 saved_lifetime = 0; + static gss_OID saved_mech = GSS_C_NO_OID; + static gss_name_t name; + static OM_uint32 last_call = 0; + OM_uint32 lifetime, now, major, minor; + int equal; + + now = time(NULL); + + if (ctxt) { + debug("Rekey has happened - updating saved versions"); + + if (saved_name != GSS_C_NO_NAME) + gss_release_name(&minor, &saved_name); + + major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL, + &saved_name, &saved_lifetime, NULL, NULL); + + if (!GSS_ERROR(major)) { + saved_mech = ctxt->oid; + saved_lifetime+= now; + } else { + /* Handle the error */ + } + return 0; + } + + if (now - last_call < 10) + return 0; + + last_call = now; + + if (saved_mech == GSS_C_NO_OID) + return 0; + + major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL, + &name, &lifetime, NULL, NULL); + if (major == GSS_S_CREDENTIALS_EXPIRED) + return 0; + else if (GSS_ERROR(major)) + return 0; + + major = gss_compare_name(&minor, saved_name, name, &equal); + gss_release_name(&minor, &name); + if (GSS_ERROR(major)) + return 0; + + if (equal && (saved_lifetime < lifetime + now - 10)) + return 1; + + return 0; +} + #endif /* GSSAPI */ diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c index 795992d9f..fd8b37183 100644 --- a/gss-serv-krb5.c +++ b/gss-serv-krb5.c @@ -1,7 +1,7 @@ /* $OpenBSD: gss-serv-krb5.c,v 1.8 2013/07/20 01:55:13 djm Exp $ */ /* - * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -121,8 +121,8 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) krb5_error_code problem; krb5_principal princ; OM_uint32 maj_status, min_status; - int len; const char *errmsg; + const char *new_ccname; if (client->creds == NULL) { debug("No credentials stored"); @@ -181,11 +181,16 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) return; } - client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache)); + new_ccname = krb5_cc_get_name(krb_context, ccache); + client->store.envvar = "KRB5CCNAME"; - len = strlen(client->store.filename) + 6; - client->store.envval = xmalloc(len); - snprintf(client->store.envval, len, "FILE:%s", client->store.filename); +#ifdef USE_CCAPI + xasprintf(&client->store.envval, "API:%s", new_ccname); + client->store.filename = NULL; +#else + xasprintf(&client->store.envval, "FILE:%s", new_ccname); + client->store.filename = xstrdup(new_ccname); +#endif #ifdef USE_PAM if (options.use_pam) @@ -197,6 +202,71 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client) return; } +int +ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store, + ssh_gssapi_client *client) +{ + krb5_ccache ccache = NULL; + krb5_principal principal = NULL; + char *name = NULL; + krb5_error_code problem; + OM_uint32 maj_status, min_status; + + if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) { + logit("krb5_cc_resolve(): %.100s", + krb5_get_err_text(krb_context, problem)); + return 0; + } + + /* Find out who the principal in this cache is */ + if ((problem = krb5_cc_get_principal(krb_context, ccache, + &principal))) { + logit("krb5_cc_get_principal(): %.100s", + krb5_get_err_text(krb_context, problem)); + krb5_cc_close(krb_context, ccache); + return 0; + } + + if ((problem = krb5_unparse_name(krb_context, principal, &name))) { + logit("krb5_unparse_name(): %.100s", + krb5_get_err_text(krb_context, problem)); + krb5_free_principal(krb_context, principal); + krb5_cc_close(krb_context, ccache); + return 0; + } + + + if (strcmp(name,client->exportedname.value)!=0) { + debug("Name in local credentials cache differs. Not storing"); + krb5_free_principal(krb_context, principal); + krb5_cc_close(krb_context, ccache); + krb5_free_unparsed_name(krb_context, name); + return 0; + } + krb5_free_unparsed_name(krb_context, name); + + /* Name matches, so lets get on with it! */ + + if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) { + logit("krb5_cc_initialize(): %.100s", + krb5_get_err_text(krb_context, problem)); + krb5_free_principal(krb_context, principal); + krb5_cc_close(krb_context, ccache); + return 0; + } + + krb5_free_principal(krb_context, principal); + + if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds, + ccache))) { + logit("gss_krb5_copy_ccache() failed. Sorry!"); + krb5_cc_close(krb_context, ccache); + return 0; + } + + return 1; +} + ssh_gssapi_mech gssapi_kerberos_mech = { "toWM5Slw5Ew8Mqkay+al2g==", "Kerberos", @@ -204,7 +274,8 @@ ssh_gssapi_mech gssapi_kerberos_mech = { NULL, &ssh_gssapi_krb5_userok, NULL, - &ssh_gssapi_krb5_storecreds + &ssh_gssapi_krb5_storecreds, + &ssh_gssapi_krb5_updatecreds }; #endif /* KRB5 */ diff --git a/gss-serv.c b/gss-serv.c index 53993d674..2f6baf70d 100644 --- a/gss-serv.c +++ b/gss-serv.c @@ -1,7 +1,7 @@ /* $OpenBSD: gss-serv.c,v 1.29 2015/05/22 03:50:02 djm Exp $ */ /* - * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -45,17 +45,22 @@ #include "session.h" #include "misc.h" #include "servconf.h" +#include "uidswap.h" #include "ssh-gss.h" +#include "monitor_wrap.h" + +extern ServerOptions options; extern ServerOptions options; static ssh_gssapi_client gssapi_client = { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER, - GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL, NULL}}; + GSS_C_NO_CREDENTIAL, GSS_C_NO_NAME, NULL, + {NULL, NULL, NULL, NULL, NULL}, 0, 0}; ssh_gssapi_mech gssapi_null_mech = - { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL}; + { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL}; #ifdef KRB5 extern ssh_gssapi_mech gssapi_kerberos_mech; @@ -141,6 +146,29 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) return (ssh_gssapi_acquire_cred(*ctx)); } +/* Unprivileged */ +char * +ssh_gssapi_server_mechanisms(void) { + gss_OID_set supported; + + ssh_gssapi_supported_oids(&supported); + return (ssh_gssapi_kex_mechs(supported, &ssh_gssapi_server_check_mech, + NULL, NULL)); +} + +/* Unprivileged */ +int +ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data, + const char *dummy) { + Gssctxt *ctx = NULL; + int res; + + res = !GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctx, oid))); + ssh_gssapi_delete_ctx(&ctx); + + return (res); +} + /* Unprivileged */ void ssh_gssapi_supported_oids(gss_OID_set *oidset) @@ -151,7 +179,9 @@ ssh_gssapi_supported_oids(gss_OID_set *oidset) gss_OID_set supported; gss_create_empty_oid_set(&min_status, oidset); - gss_indicate_mechs(&min_status, &supported); + + if (GSS_ERROR(gss_indicate_mechs(&min_status, &supported))) + return; while (supported_mechs[i]->name != NULL) { if (GSS_ERROR(gss_test_oid_set_member(&min_status, @@ -277,8 +307,48 @@ OM_uint32 ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client) { int i = 0; + int equal = 0; + gss_name_t new_name = GSS_C_NO_NAME; + gss_buffer_desc ename = GSS_C_EMPTY_BUFFER; + + if (options.gss_store_rekey && client->used && ctx->client_creds) { + if (client->mech->oid.length != ctx->oid->length || + (memcmp(client->mech->oid.elements, + ctx->oid->elements, ctx->oid->length) !=0)) { + debug("Rekeyed credentials have different mechanism"); + return GSS_S_COMPLETE; + } + + if ((ctx->major = gss_inquire_cred_by_mech(&ctx->minor, + ctx->client_creds, ctx->oid, &new_name, + NULL, NULL, NULL))) { + ssh_gssapi_error(ctx); + return (ctx->major); + } + + ctx->major = gss_compare_name(&ctx->minor, client->name, + new_name, &equal); + + if (GSS_ERROR(ctx->major)) { + ssh_gssapi_error(ctx); + return (ctx->major); + } + + if (!equal) { + debug("Rekeyed credentials have different name"); + return GSS_S_COMPLETE; + } - gss_buffer_desc ename; + debug("Marking rekeyed credentials for export"); + + gss_release_name(&ctx->minor, &client->name); + gss_release_cred(&ctx->minor, &client->creds); + client->name = new_name; + client->creds = ctx->client_creds; + ctx->client_creds = GSS_C_NO_CREDENTIAL; + client->updated = 1; + return GSS_S_COMPLETE; + } client->mech = NULL; @@ -293,6 +363,13 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client) if (client->mech == NULL) return GSS_S_FAILURE; + if (ctx->client_creds && + (ctx->major = gss_inquire_cred_by_mech(&ctx->minor, + ctx->client_creds, ctx->oid, &client->name, NULL, NULL, NULL))) { + ssh_gssapi_error(ctx); + return (ctx->major); + } + if ((ctx->major = gss_display_name(&ctx->minor, ctx->client, &client->displayname, NULL))) { ssh_gssapi_error(ctx); @@ -310,6 +387,8 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client) return (ctx->major); } + gss_release_buffer(&ctx->minor, &ename); + /* We can't copy this structure, so we just move the pointer to it */ client->creds = ctx->client_creds; ctx->client_creds = GSS_C_NO_CREDENTIAL; @@ -357,7 +436,7 @@ ssh_gssapi_do_child(char ***envp, u_int *envsizep) /* Privileged */ int -ssh_gssapi_userok(char *user) +ssh_gssapi_userok(char *user, struct passwd *pw) { OM_uint32 lmin; @@ -367,9 +446,11 @@ ssh_gssapi_userok(char *user) return 0; } if (gssapi_client.mech && gssapi_client.mech->userok) - if ((*gssapi_client.mech->userok)(&gssapi_client, user)) + if ((*gssapi_client.mech->userok)(&gssapi_client, user)) { + gssapi_client.used = 1; + gssapi_client.store.owner = pw; return 1; - else { + } else { /* Destroy delegated credentials if userok fails */ gss_release_buffer(&lmin, &gssapi_client.displayname); gss_release_buffer(&lmin, &gssapi_client.exportedname); @@ -383,14 +464,90 @@ ssh_gssapi_userok(char *user) return (0); } -/* Privileged */ -OM_uint32 -ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic) +/* These bits are only used for rekeying. The unpriviledged child is running + * as the user, the monitor is root. + * + * In the child, we want to : + * *) Ask the monitor to store our credentials into the store we specify + * *) If it succeeds, maybe do a PAM update + */ + +/* Stuff for PAM */ + +#ifdef USE_PAM +static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg, + struct pam_response **resp, void *data) { - ctx->major = gss_verify_mic(&ctx->minor, ctx->context, - gssbuf, gssmic, NULL); + return (PAM_CONV_ERR); +} +#endif - return (ctx->major); +void +ssh_gssapi_rekey_creds(void) { + int ok; + int ret; +#ifdef USE_PAM + pam_handle_t *pamh = NULL; + struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL}; + char *envstr; +#endif + + if (gssapi_client.store.filename == NULL && + gssapi_client.store.envval == NULL && + gssapi_client.store.envvar == NULL) + return; + + ok = PRIVSEP(ssh_gssapi_update_creds(&gssapi_client.store)); + + if (!ok) + return; + + debug("Rekeyed credentials stored successfully"); + + /* Actually managing to play with the ssh pam stack from here will + * be next to impossible. In any case, we may want different options + * for rekeying. So, use our own :) + */ +#ifdef USE_PAM + if (!use_privsep) { + debug("Not even going to try and do PAM with privsep disabled"); + return; + } + + ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name, + &pamconv, &pamh); + if (ret) + return; + + xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar, + gssapi_client.store.envval); + + ret = pam_putenv(pamh, envstr); + if (!ret) + pam_setcred(pamh, PAM_REINITIALIZE_CRED); + pam_end(pamh, PAM_SUCCESS); +#endif +} + +int +ssh_gssapi_update_creds(ssh_gssapi_ccache *store) { + int ok = 0; + + /* Check we've got credentials to store */ + if (!gssapi_client.updated) + return 0; + + gssapi_client.updated = 0; + + temporarily_use_uid(gssapi_client.store.owner); + if (gssapi_client.mech && gssapi_client.mech->updatecreds) + ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client); + else + debug("No update function for this mechanism"); + + restore_uid(); + + return ok; } #endif diff --git a/kex.c b/kex.c index 50c7a0f9b..c17d652c9 100644 --- a/kex.c +++ b/kex.c @@ -55,6 +55,10 @@ #include "sshbuf.h" #include "digest.h" +#ifdef GSSAPI +#include "ssh-gss.h" +#endif + #if OPENSSL_VERSION_NUMBER >= 0x00907000L # if defined(HAVE_EVP_SHA256) # define evp_ssh_sha256 EVP_sha256 @@ -113,6 +117,14 @@ static const struct kexalg kexalgs[] = { #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */ { NULL, -1, -1, -1}, }; +static const struct kexalg kexalg_prefixes[] = { +#ifdef GSSAPI + { KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, SSH_DIGEST_SHA1 }, + { KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, SSH_DIGEST_SHA1 }, + { KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, SSH_DIGEST_SHA1 }, +#endif + { NULL, -1, -1, -1 }, +}; char * kex_alg_list(char sep) @@ -145,6 +157,10 @@ kex_alg_by_name(const char *name) if (strcmp(k->name, name) == 0) return k; } + for (k = kexalg_prefixes; k->name != NULL; k++) { + if (strncmp(k->name, name, strlen(k->name)) == 0) + return k; + } return NULL; } @@ -587,6 +603,9 @@ kex_free(struct kex *kex) sshbuf_free(kex->peer); sshbuf_free(kex->my); free(kex->session_id); +#ifdef GSSAPI + free(kex->gss_host); +#endif /* GSSAPI */ free(kex->client_version_string); free(kex->server_version_string); free(kex->failed_choice); diff --git a/kex.h b/kex.h index c35195568..8ed459a76 100644 --- a/kex.h +++ b/kex.h @@ -98,6 +98,9 @@ enum kex_exchange { KEX_DH_GEX_SHA256, KEX_ECDH_SHA2, KEX_C25519_SHA256, + KEX_GSS_GRP1_SHA1, + KEX_GSS_GRP14_SHA1, + KEX_GSS_GEX_SHA1, KEX_MAX }; @@ -146,6 +149,12 @@ struct kex { u_int flags; int hash_alg; int ec_nid; +#ifdef GSSAPI + int gss_deleg_creds; + int gss_trust_dns; + char *gss_host; + char *gss_client; +#endif char *client_version_string; char *server_version_string; char *failed_choice; @@ -196,6 +205,11 @@ int kexecdh_server(struct ssh *); int kexc25519_client(struct ssh *); int kexc25519_server(struct ssh *); +#ifdef GSSAPI +int kexgss_client(struct ssh *); +int kexgss_server(struct ssh *); +#endif + int kex_dh_hash(int, const char *, const char *, const u_char *, size_t, const u_char *, size_t, const u_char *, size_t, const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *); diff --git a/kexgssc.c b/kexgssc.c new file mode 100644 index 000000000..10447f2b0 --- /dev/null +++ b/kexgssc.c @@ -0,0 +1,338 @@ +/* + * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#ifdef GSSAPI + +#include "includes.h" + +#include +#include + +#include + +#include "xmalloc.h" +#include "buffer.h" +#include "ssh2.h" +#include "key.h" +#include "cipher.h" +#include "kex.h" +#include "log.h" +#include "packet.h" +#include "dh.h" +#include "digest.h" + +#include "ssh-gss.h" + +int +kexgss_client(struct ssh *ssh) { + gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; + gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr; + Gssctxt *ctxt; + OM_uint32 maj_status, min_status, ret_flags; + u_int klen, kout, slen = 0, strlen; + DH *dh; + BIGNUM *dh_server_pub = NULL; + BIGNUM *shared_secret = NULL; + BIGNUM *p = NULL; + BIGNUM *g = NULL; + u_char *kbuf; + u_char *serverhostkey = NULL; + u_char *empty = ""; + char *msg; + int type = 0; + int first = 1; + int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX; + u_char hash[SSH_DIGEST_MAX_LENGTH]; + size_t hashlen; + + /* Initialise our GSSAPI world */ + ssh_gssapi_build_ctx(&ctxt); + if (ssh_gssapi_id_kex(ctxt, ssh->kex->name, ssh->kex->kex_type) + == GSS_C_NO_OID) + fatal("Couldn't identify host exchange"); + + if (ssh_gssapi_import_name(ctxt, ssh->kex->gss_host)) + fatal("Couldn't import hostname"); + + if (ssh->kex->gss_client && + ssh_gssapi_client_identity(ctxt, ssh->kex->gss_client)) + fatal("Couldn't acquire client credentials"); + + switch (ssh->kex->kex_type) { + case KEX_GSS_GRP1_SHA1: + dh = dh_new_group1(); + break; + case KEX_GSS_GRP14_SHA1: + dh = dh_new_group14(); + break; + case KEX_GSS_GEX_SHA1: + debug("Doing group exchange\n"); + nbits = dh_estimate(ssh->kex->we_need * 8); + packet_start(SSH2_MSG_KEXGSS_GROUPREQ); + packet_put_int(min); + packet_put_int(nbits); + packet_put_int(max); + + packet_send(); + + packet_read_expect(SSH2_MSG_KEXGSS_GROUP); + + if ((p = BN_new()) == NULL) + fatal("BN_new() failed"); + packet_get_bignum2(p); + if ((g = BN_new()) == NULL) + fatal("BN_new() failed"); + packet_get_bignum2(g); + packet_check_eom(); + + if (BN_num_bits(p) < min || BN_num_bits(p) > max) + fatal("GSSGRP_GEX group out of range: %d !< %d !< %d", + min, BN_num_bits(p), max); + + dh = dh_new_group(g, p); + break; + default: + fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type); + } + + /* Step 1 - e is dh->pub_key */ + dh_gen_key(dh, ssh->kex->we_need * 8); + + /* This is f, we initialise it now to make life easier */ + dh_server_pub = BN_new(); + if (dh_server_pub == NULL) + fatal("dh_server_pub == NULL"); + + token_ptr = GSS_C_NO_BUFFER; + + do { + debug("Calling gss_init_sec_context"); + + maj_status = ssh_gssapi_init_ctx(ctxt, + ssh->kex->gss_deleg_creds, token_ptr, &send_tok, + &ret_flags); + + if (GSS_ERROR(maj_status)) { + if (send_tok.length != 0) { + packet_start(SSH2_MSG_KEXGSS_CONTINUE); + packet_put_string(send_tok.value, + send_tok.length); + } + fatal("gss_init_context failed"); + } + + /* If we've got an old receive buffer get rid of it */ + if (token_ptr != GSS_C_NO_BUFFER) + free(recv_tok.value); + + if (maj_status == GSS_S_COMPLETE) { + /* If mutual state flag is not true, kex fails */ + if (!(ret_flags & GSS_C_MUTUAL_FLAG)) + fatal("Mutual authentication failed"); + + /* If integ avail flag is not true kex fails */ + if (!(ret_flags & GSS_C_INTEG_FLAG)) + fatal("Integrity check failed"); + } + + /* + * If we have data to send, then the last message that we + * received cannot have been a 'complete'. + */ + if (send_tok.length != 0) { + if (first) { + packet_start(SSH2_MSG_KEXGSS_INIT); + packet_put_string(send_tok.value, + send_tok.length); + packet_put_bignum2(dh->pub_key); + first = 0; + } else { + packet_start(SSH2_MSG_KEXGSS_CONTINUE); + packet_put_string(send_tok.value, + send_tok.length); + } + packet_send(); + gss_release_buffer(&min_status, &send_tok); + + /* If we've sent them data, they should reply */ + do { + type = packet_read(); + if (type == SSH2_MSG_KEXGSS_HOSTKEY) { + debug("Received KEXGSS_HOSTKEY"); + if (serverhostkey) + fatal("Server host key received more than once"); + serverhostkey = + packet_get_string(&slen); + } + } while (type == SSH2_MSG_KEXGSS_HOSTKEY); + + switch (type) { + case SSH2_MSG_KEXGSS_CONTINUE: + debug("Received GSSAPI_CONTINUE"); + if (maj_status == GSS_S_COMPLETE) + fatal("GSSAPI Continue received from server when complete"); + recv_tok.value = packet_get_string(&strlen); + recv_tok.length = strlen; + break; + case SSH2_MSG_KEXGSS_COMPLETE: + debug("Received GSSAPI_COMPLETE"); + packet_get_bignum2(dh_server_pub); + msg_tok.value = packet_get_string(&strlen); + msg_tok.length = strlen; + + /* Is there a token included? */ + if (packet_get_char()) { + recv_tok.value= + packet_get_string(&strlen); + recv_tok.length = strlen; + /* If we're already complete - protocol error */ + if (maj_status == GSS_S_COMPLETE) + packet_disconnect("Protocol error: received token when complete"); + } else { + /* No token included */ + if (maj_status != GSS_S_COMPLETE) + packet_disconnect("Protocol error: did not receive final token"); + } + break; + case SSH2_MSG_KEXGSS_ERROR: + debug("Received Error"); + maj_status = packet_get_int(); + min_status = packet_get_int(); + msg = packet_get_string(NULL); + (void) packet_get_string_ptr(NULL); + fatal("GSSAPI Error: \n%.400s",msg); + default: + packet_disconnect("Protocol error: didn't expect packet type %d", + type); + } + token_ptr = &recv_tok; + } else { + /* No data, and not complete */ + if (maj_status != GSS_S_COMPLETE) + fatal("Not complete, and no token output"); + } + } while (maj_status & GSS_S_CONTINUE_NEEDED); + + /* + * We _must_ have received a COMPLETE message in reply from the + * server, which will have set dh_server_pub and msg_tok + */ + + if (type != SSH2_MSG_KEXGSS_COMPLETE) + fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it"); + + /* Check f in range [1, p-1] */ + if (!dh_pub_is_valid(dh, dh_server_pub)) + packet_disconnect("bad server public DH value"); + + /* compute K=f^x mod p */ + klen = DH_size(dh); + kbuf = xmalloc(klen); + kout = DH_compute_key(kbuf, dh_server_pub, dh); + if (kout < 0) + fatal("DH_compute_key: failed"); + + shared_secret = BN_new(); + if (shared_secret == NULL) + fatal("kexgss_client: BN_new failed"); + + if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) + fatal("kexdh_client: BN_bin2bn failed"); + + memset(kbuf, 0, klen); + free(kbuf); + + hashlen = sizeof(hash); + switch (ssh->kex->kex_type) { + case KEX_GSS_GRP1_SHA1: + case KEX_GSS_GRP14_SHA1: + kex_dh_hash( + ssh->kex->hash_alg, + ssh->kex->client_version_string, + ssh->kex->server_version_string, + buffer_ptr(ssh->kex->my), buffer_len(ssh->kex->my), + buffer_ptr(ssh->kex->peer), buffer_len(ssh->kex->peer), + (serverhostkey ? serverhostkey : empty), slen, + dh->pub_key, /* e */ + dh_server_pub, /* f */ + shared_secret, /* K */ + hash, &hashlen + ); + break; + case KEX_GSS_GEX_SHA1: + kexgex_hash( + ssh->kex->hash_alg, + ssh->kex->client_version_string, + ssh->kex->server_version_string, + buffer_ptr(ssh->kex->my), buffer_len(ssh->kex->my), + buffer_ptr(ssh->kex->peer), buffer_len(ssh->kex->peer), + (serverhostkey ? serverhostkey : empty), slen, + min, nbits, max, + dh->p, dh->g, + dh->pub_key, + dh_server_pub, + shared_secret, + hash, &hashlen + ); + break; + default: + fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type); + } + + gssbuf.value = hash; + gssbuf.length = hashlen; + + /* Verify that the hash matches the MIC we just got. */ + if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok))) + packet_disconnect("Hash's MIC didn't verify"); + + free(msg_tok.value); + + DH_free(dh); + free(serverhostkey); + BN_clear_free(dh_server_pub); + + /* save session id */ + if (ssh->kex->session_id == NULL) { + ssh->kex->session_id_len = hashlen; + ssh->kex->session_id = xmalloc(ssh->kex->session_id_len); + memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len); + } + + if (ssh->kex->gss_deleg_creds) + ssh_gssapi_credentials_updated(ctxt); + + if (gss_kex_context == NULL) + gss_kex_context = ctxt; + else + ssh_gssapi_delete_ctx(&ctxt); + + kex_derive_keys_bn(ssh, hash, hashlen, shared_secret); + BN_clear_free(shared_secret); + return kex_send_newkeys(ssh); +} + +#endif /* GSSAPI */ diff --git a/kexgsss.c b/kexgsss.c new file mode 100644 index 000000000..38ca082ba --- /dev/null +++ b/kexgsss.c @@ -0,0 +1,295 @@ +/* + * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#ifdef GSSAPI + +#include + +#include +#include + +#include "xmalloc.h" +#include "buffer.h" +#include "ssh2.h" +#include "key.h" +#include "cipher.h" +#include "kex.h" +#include "log.h" +#include "packet.h" +#include "dh.h" +#include "ssh-gss.h" +#include "monitor_wrap.h" +#include "misc.h" +#include "servconf.h" +#include "digest.h" + +extern ServerOptions options; + +int +kexgss_server(struct ssh *ssh) +{ + OM_uint32 maj_status, min_status; + + /* + * Some GSSAPI implementations use the input value of ret_flags (an + * output variable) as a means of triggering mechanism specific + * features. Initializing it to zero avoids inadvertently + * activating this non-standard behaviour. + */ + + OM_uint32 ret_flags = 0; + gss_buffer_desc gssbuf, recv_tok, msg_tok; + gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; + Gssctxt *ctxt = NULL; + u_int slen, klen, kout; + u_char *kbuf; + DH *dh; + int min = -1, max = -1, nbits = -1; + BIGNUM *shared_secret = NULL; + BIGNUM *dh_client_pub = NULL; + int type = 0; + gss_OID oid; + char *mechs; + u_char hash[SSH_DIGEST_MAX_LENGTH]; + size_t hashlen; + + /* Initialise GSSAPI */ + + /* If we're rekeying, privsep means that some of the private structures + * in the GSSAPI code are no longer available. This kludges them back + * into life + */ + if (!ssh_gssapi_oid_table_ok()) { + mechs = ssh_gssapi_server_mechanisms(); + free(mechs); + } + + debug2("%s: Identifying %s", __func__, ssh->kex->name); + oid = ssh_gssapi_id_kex(NULL, ssh->kex->name, ssh->kex->kex_type); + if (oid == GSS_C_NO_OID) + fatal("Unknown gssapi mechanism"); + + debug2("%s: Acquiring credentials", __func__); + + if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid)))) + fatal("Unable to acquire credentials for the server"); + + switch (ssh->kex->kex_type) { + case KEX_GSS_GRP1_SHA1: + dh = dh_new_group1(); + break; + case KEX_GSS_GRP14_SHA1: + dh = dh_new_group14(); + break; + case KEX_GSS_GEX_SHA1: + debug("Doing group exchange"); + packet_read_expect(SSH2_MSG_KEXGSS_GROUPREQ); + min = packet_get_int(); + nbits = packet_get_int(); + max = packet_get_int(); + packet_check_eom(); + if (max < min || nbits < min || max < nbits) + fatal("GSS_GEX, bad parameters: %d !< %d !< %d", + min, nbits, max); + dh = PRIVSEP(choose_dh(MAX(DH_GRP_MIN, min), + nbits, MIN(DH_GRP_MAX, max))); + if (dh == NULL) + packet_disconnect("Protocol error: no matching group found"); + + packet_start(SSH2_MSG_KEXGSS_GROUP); + packet_put_bignum2(dh->p); + packet_put_bignum2(dh->g); + packet_send(); + + packet_write_wait(); + break; + default: + fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type); + } + + dh_gen_key(dh, ssh->kex->we_need * 8); + + do { + debug("Wait SSH2_MSG_GSSAPI_INIT"); + type = packet_read(); + switch(type) { + case SSH2_MSG_KEXGSS_INIT: + if (dh_client_pub != NULL) + fatal("Received KEXGSS_INIT after initialising"); + recv_tok.value = packet_get_string(&slen); + recv_tok.length = slen; + + if ((dh_client_pub = BN_new()) == NULL) + fatal("dh_client_pub == NULL"); + + packet_get_bignum2(dh_client_pub); + + /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */ + break; + case SSH2_MSG_KEXGSS_CONTINUE: + recv_tok.value = packet_get_string(&slen); + recv_tok.length = slen; + break; + default: + packet_disconnect( + "Protocol error: didn't expect packet type %d", + type); + } + + maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok, + &send_tok, &ret_flags)); + + free(recv_tok.value); + + if (maj_status != GSS_S_COMPLETE && send_tok.length == 0) + fatal("Zero length token output when incomplete"); + + if (dh_client_pub == NULL) + fatal("No client public key"); + + if (maj_status & GSS_S_CONTINUE_NEEDED) { + debug("Sending GSSAPI_CONTINUE"); + packet_start(SSH2_MSG_KEXGSS_CONTINUE); + packet_put_string(send_tok.value, send_tok.length); + packet_send(); + gss_release_buffer(&min_status, &send_tok); + } + } while (maj_status & GSS_S_CONTINUE_NEEDED); + + if (GSS_ERROR(maj_status)) { + if (send_tok.length > 0) { + packet_start(SSH2_MSG_KEXGSS_CONTINUE); + packet_put_string(send_tok.value, send_tok.length); + packet_send(); + } + fatal("accept_ctx died"); + } + + if (!(ret_flags & GSS_C_MUTUAL_FLAG)) + fatal("Mutual Authentication flag wasn't set"); + + if (!(ret_flags & GSS_C_INTEG_FLAG)) + fatal("Integrity flag wasn't set"); + + if (!dh_pub_is_valid(dh, dh_client_pub)) + packet_disconnect("bad client public DH value"); + + klen = DH_size(dh); + kbuf = xmalloc(klen); + kout = DH_compute_key(kbuf, dh_client_pub, dh); + if (kout < 0) + fatal("DH_compute_key: failed"); + + shared_secret = BN_new(); + if (shared_secret == NULL) + fatal("kexgss_server: BN_new failed"); + + if (BN_bin2bn(kbuf, kout, shared_secret) == NULL) + fatal("kexgss_server: BN_bin2bn failed"); + + memset(kbuf, 0, klen); + free(kbuf); + + hashlen = sizeof(hash); + switch (ssh->kex->kex_type) { + case KEX_GSS_GRP1_SHA1: + case KEX_GSS_GRP14_SHA1: + kex_dh_hash( + ssh->kex->hash_alg, + ssh->kex->client_version_string, ssh->kex->server_version_string, + buffer_ptr(ssh->kex->peer), buffer_len(ssh->kex->peer), + buffer_ptr(ssh->kex->my), buffer_len(ssh->kex->my), + NULL, 0, /* Change this if we start sending host keys */ + dh_client_pub, dh->pub_key, shared_secret, + hash, &hashlen + ); + break; + case KEX_GSS_GEX_SHA1: + kexgex_hash( + ssh->kex->hash_alg, + ssh->kex->client_version_string, ssh->kex->server_version_string, + buffer_ptr(ssh->kex->peer), buffer_len(ssh->kex->peer), + buffer_ptr(ssh->kex->my), buffer_len(ssh->kex->my), + NULL, 0, + min, nbits, max, + dh->p, dh->g, + dh_client_pub, + dh->pub_key, + shared_secret, + hash, &hashlen + ); + break; + default: + fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type); + } + + BN_clear_free(dh_client_pub); + + if (ssh->kex->session_id == NULL) { + ssh->kex->session_id_len = hashlen; + ssh->kex->session_id = xmalloc(ssh->kex->session_id_len); + memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len); + } + + gssbuf.value = hash; + gssbuf.length = hashlen; + + if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok)))) + fatal("Couldn't get MIC"); + + packet_start(SSH2_MSG_KEXGSS_COMPLETE); + packet_put_bignum2(dh->pub_key); + packet_put_string(msg_tok.value,msg_tok.length); + + if (send_tok.length != 0) { + packet_put_char(1); /* true */ + packet_put_string(send_tok.value, send_tok.length); + } else { + packet_put_char(0); /* false */ + } + packet_send(); + + gss_release_buffer(&min_status, &send_tok); + gss_release_buffer(&min_status, &msg_tok); + + if (gss_kex_context == NULL) + gss_kex_context = ctxt; + else + ssh_gssapi_delete_ctx(&ctxt); + + DH_free(dh); + + kex_derive_keys_bn(ssh, hash, hashlen, shared_secret); + BN_clear_free(shared_secret); + kex_send_newkeys(ssh); + + /* If this was a rekey, then save out any delegated credentials we + * just exchanged. */ + if (options.gss_store_rekey) + ssh_gssapi_rekey_creds(); + return 0; +} +#endif /* GSSAPI */ diff --git a/monitor.c b/monitor.c index cb57bd066..05bb48a8e 100644 --- a/monitor.c +++ b/monitor.c @@ -158,6 +158,8 @@ int mm_answer_gss_setup_ctx(int, Buffer *); int mm_answer_gss_accept_ctx(int, Buffer *); int mm_answer_gss_userok(int, Buffer *); int mm_answer_gss_checkmic(int, Buffer *); +int mm_answer_gss_sign(int, Buffer *); +int mm_answer_gss_updatecreds(int, Buffer *); #endif #ifdef SSH_AUDIT_EVENTS @@ -235,11 +237,18 @@ struct mon_table mon_dispatch_proto20[] = { {MONITOR_REQ_GSSSTEP, MON_ISAUTH, mm_answer_gss_accept_ctx}, {MONITOR_REQ_GSSUSEROK, MON_AUTH, mm_answer_gss_userok}, {MONITOR_REQ_GSSCHECKMIC, MON_ISAUTH, mm_answer_gss_checkmic}, + {MONITOR_REQ_GSSSIGN, MON_ONCE, mm_answer_gss_sign}, #endif {0, 0, NULL} }; struct mon_table mon_dispatch_postauth20[] = { +#ifdef GSSAPI + {MONITOR_REQ_GSSSETUP, 0, mm_answer_gss_setup_ctx}, + {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx}, + {MONITOR_REQ_GSSSIGN, 0, mm_answer_gss_sign}, + {MONITOR_REQ_GSSUPCREDS, 0, mm_answer_gss_updatecreds}, +#endif #ifdef WITH_OPENSSL {MONITOR_REQ_MODULI, 0, mm_answer_moduli}, #endif @@ -354,6 +363,10 @@ monitor_child_preauth(Authctxt *_authctxt, struct monitor *pmonitor) /* Permit requests for moduli and signatures */ monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); +#ifdef GSSAPI + /* and for the GSSAPI key exchange */ + monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1); +#endif } else { mon_dispatch = mon_dispatch_proto15; @@ -462,6 +475,10 @@ monitor_child_postauth(struct monitor *pmonitor) monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1); monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1); monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); +#ifdef GSSAPI + /* and for the GSSAPI key exchange */ + monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1); +#endif } else { mon_dispatch = mon_dispatch_postauth15; monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1); @@ -1876,6 +1893,13 @@ monitor_apply_keystate(struct monitor *pmonitor) # endif #endif /* WITH_OPENSSL */ kex->kex[KEX_C25519_SHA256] = kexc25519_server; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; + } +#endif kex->load_host_public_key=&get_hostkey_public_by_type; kex->load_host_private_key=&get_hostkey_private_by_type; kex->host_key_index=&get_hostkey_index; @@ -1975,6 +1999,9 @@ mm_answer_gss_setup_ctx(int sock, Buffer *m) OM_uint32 major; u_int len; + if (!options.gss_authentication && !options.gss_keyex) + fatal("In GSSAPI monitor when GSSAPI is disabled"); + goid.elements = buffer_get_string(m, &len); goid.length = len; @@ -2002,6 +2029,9 @@ mm_answer_gss_accept_ctx(int sock, Buffer *m) OM_uint32 flags = 0; /* GSI needs this */ u_int len; + if (!options.gss_authentication && !options.gss_keyex) + fatal("In GSSAPI monitor when GSSAPI is disabled"); + in.value = buffer_get_string(m, &len); in.length = len; major = ssh_gssapi_accept_ctx(gsscontext, &in, &out, &flags); @@ -2019,6 +2049,7 @@ mm_answer_gss_accept_ctx(int sock, Buffer *m) monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0); monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1); monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1); + monitor_permit(mon_dispatch, MONITOR_REQ_GSSSIGN, 1); } return (0); } @@ -2030,6 +2061,9 @@ mm_answer_gss_checkmic(int sock, Buffer *m) OM_uint32 ret; u_int len; + if (!options.gss_authentication && !options.gss_keyex) + fatal("In GSSAPI monitor when GSSAPI is disabled"); + gssbuf.value = buffer_get_string(m, &len); gssbuf.length = len; mic.value = buffer_get_string(m, &len); @@ -2056,7 +2090,11 @@ mm_answer_gss_userok(int sock, Buffer *m) { int authenticated; - authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user); + if (!options.gss_authentication && !options.gss_keyex) + fatal("In GSSAPI monitor when GSSAPI is disabled"); + + authenticated = authctxt->valid && + ssh_gssapi_userok(authctxt->user, authctxt->pw); buffer_clear(m); buffer_put_int(m, authenticated); @@ -2069,5 +2107,73 @@ mm_answer_gss_userok(int sock, Buffer *m) /* Monitor loop will terminate if authenticated */ return (authenticated); } + +int +mm_answer_gss_sign(int socket, Buffer *m) +{ + gss_buffer_desc data; + gss_buffer_desc hash = GSS_C_EMPTY_BUFFER; + OM_uint32 major, minor; + u_int len; + + if (!options.gss_authentication && !options.gss_keyex) + fatal("In GSSAPI monitor when GSSAPI is disabled"); + + data.value = buffer_get_string(m, &len); + data.length = len; + if (data.length != 20) + fatal("%s: data length incorrect: %d", __func__, + (int) data.length); + + /* Save the session ID on the first time around */ + if (session_id2_len == 0) { + session_id2_len = data.length; + session_id2 = xmalloc(session_id2_len); + memcpy(session_id2, data.value, session_id2_len); + } + major = ssh_gssapi_sign(gsscontext, &data, &hash); + + free(data.value); + + buffer_clear(m); + buffer_put_int(m, major); + buffer_put_string(m, hash.value, hash.length); + + mm_request_send(socket, MONITOR_ANS_GSSSIGN, m); + + gss_release_buffer(&minor, &hash); + + /* Turn on getpwnam permissions */ + monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1); + + /* And credential updating, for when rekeying */ + monitor_permit(mon_dispatch, MONITOR_REQ_GSSUPCREDS, 1); + + return (0); +} + +int +mm_answer_gss_updatecreds(int socket, Buffer *m) { + ssh_gssapi_ccache store; + int ok; + + store.filename = buffer_get_string(m, NULL); + store.envvar = buffer_get_string(m, NULL); + store.envval = buffer_get_string(m, NULL); + + ok = ssh_gssapi_update_creds(&store); + + free(store.filename); + free(store.envvar); + free(store.envval); + + buffer_clear(m); + buffer_put_int(m, ok); + + mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m); + + return(0); +} + #endif /* GSSAPI */ diff --git a/monitor.h b/monitor.h index 93b8b66dd..bc50ade1f 100644 --- a/monitor.h +++ b/monitor.h @@ -65,6 +65,9 @@ enum monitor_reqtype { MONITOR_REQ_PAM_FREE_CTX = 110, MONITOR_ANS_PAM_FREE_CTX = 111, MONITOR_REQ_AUDIT_EVENT = 112, MONITOR_REQ_AUDIT_COMMAND = 113, + MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151, + MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153, + }; struct mm_master; diff --git a/monitor_wrap.c b/monitor_wrap.c index 99dc13b61..5a9f1b52d 100644 --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -1073,7 +1073,7 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic) } int -mm_ssh_gssapi_userok(char *user) +mm_ssh_gssapi_userok(char *user, struct passwd *pw) { Buffer m; int authenticated = 0; @@ -1090,5 +1090,50 @@ mm_ssh_gssapi_userok(char *user) debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not "); return (authenticated); } + +OM_uint32 +mm_ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *data, gss_buffer_desc *hash) +{ + Buffer m; + OM_uint32 major; + u_int len; + + buffer_init(&m); + buffer_put_string(&m, data->value, data->length); + + mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSIGN, &m); + mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSIGN, &m); + + major = buffer_get_int(&m); + hash->value = buffer_get_string(&m, &len); + hash->length = len; + + buffer_free(&m); + + return(major); +} + +int +mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store) +{ + Buffer m; + int ok; + + buffer_init(&m); + + buffer_put_cstring(&m, store->filename ? store->filename : ""); + buffer_put_cstring(&m, store->envvar ? store->envvar : ""); + buffer_put_cstring(&m, store->envval ? store->envval : ""); + + mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUPCREDS, &m); + mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUPCREDS, &m); + + ok = buffer_get_int(&m); + + buffer_free(&m); + + return (ok); +} + #endif /* GSSAPI */ diff --git a/monitor_wrap.h b/monitor_wrap.h index 9fd02b30c..b5414c298 100644 --- a/monitor_wrap.h +++ b/monitor_wrap.h @@ -60,8 +60,10 @@ BIGNUM *mm_auth_rsa_generate_challenge(Key *); OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **, gss_OID); OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *, gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *); -int mm_ssh_gssapi_userok(char *user); +int mm_ssh_gssapi_userok(char *user, struct passwd *); OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t); +OM_uint32 mm_ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t); +int mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *); #endif #ifdef USE_PAM diff --git a/readconf.c b/readconf.c index c177202b1..e019195e7 100644 --- a/readconf.c +++ b/readconf.c @@ -160,6 +160,8 @@ typedef enum { oClearAllForwardings, oNoHostAuthenticationForLocalhost, oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout, oAddressFamily, oGssAuthentication, oGssDelegateCreds, + oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey, + oGssServerIdentity, oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly, oSendEnv, oControlPath, oControlMaster, oControlPersist, oHashKnownHosts, @@ -205,10 +207,19 @@ static struct { { "afstokenpassing", oUnsupported }, #if defined(GSSAPI) { "gssapiauthentication", oGssAuthentication }, + { "gssapikeyexchange", oGssKeyEx }, { "gssapidelegatecredentials", oGssDelegateCreds }, + { "gssapitrustdns", oGssTrustDns }, + { "gssapiclientidentity", oGssClientIdentity }, + { "gssapiserveridentity", oGssServerIdentity }, + { "gssapirenewalforcesrekey", oGssRenewalRekey }, #else { "gssapiauthentication", oUnsupported }, + { "gssapikeyexchange", oUnsupported }, { "gssapidelegatecredentials", oUnsupported }, + { "gssapitrustdns", oUnsupported }, + { "gssapiclientidentity", oUnsupported }, + { "gssapirenewalforcesrekey", oUnsupported }, #endif { "fallbacktorsh", oDeprecated }, { "usersh", oDeprecated }, @@ -962,10 +973,30 @@ parse_time: intptr = &options->gss_authentication; goto parse_flag; + case oGssKeyEx: + intptr = &options->gss_keyex; + goto parse_flag; + case oGssDelegateCreds: intptr = &options->gss_deleg_creds; goto parse_flag; + case oGssTrustDns: + intptr = &options->gss_trust_dns; + goto parse_flag; + + case oGssClientIdentity: + charptr = &options->gss_client_identity; + goto parse_string; + + case oGssServerIdentity: + charptr = &options->gss_server_identity; + goto parse_string; + + case oGssRenewalRekey: + intptr = &options->gss_renewal_rekey; + goto parse_flag; + case oBatchMode: intptr = &options->batch_mode; goto parse_flag; @@ -1777,7 +1808,12 @@ initialize_options(Options * options) options->pubkey_authentication = -1; options->challenge_response_authentication = -1; options->gss_authentication = -1; + options->gss_keyex = -1; options->gss_deleg_creds = -1; + options->gss_trust_dns = -1; + options->gss_renewal_rekey = -1; + options->gss_client_identity = NULL; + options->gss_server_identity = NULL; options->password_authentication = -1; options->kbd_interactive_authentication = -1; options->kbd_interactive_devices = NULL; @@ -1921,8 +1957,14 @@ fill_default_options(Options * options) options->challenge_response_authentication = 1; if (options->gss_authentication == -1) options->gss_authentication = 0; + if (options->gss_keyex == -1) + options->gss_keyex = 0; if (options->gss_deleg_creds == -1) options->gss_deleg_creds = 0; + if (options->gss_trust_dns == -1) + options->gss_trust_dns = 0; + if (options->gss_renewal_rekey == -1) + options->gss_renewal_rekey = 0; if (options->password_authentication == -1) options->password_authentication = 1; if (options->kbd_interactive_authentication == -1) diff --git a/readconf.h b/readconf.h index cef55f71c..fd3d7c75d 100644 --- a/readconf.h +++ b/readconf.h @@ -45,7 +45,12 @@ typedef struct { int challenge_response_authentication; /* Try S/Key or TIS, authentication. */ int gss_authentication; /* Try GSS authentication */ + int gss_keyex; /* Try GSS key exchange */ int gss_deleg_creds; /* Delegate GSS credentials */ + int gss_trust_dns; /* Trust DNS for GSS canonicalization */ + int gss_renewal_rekey; /* Credential renewal forces rekey */ + char *gss_client_identity; /* Principal to initiate GSSAPI with */ + char *gss_server_identity; /* GSSAPI target principal */ int password_authentication; /* Try password * authentication. */ int kbd_interactive_authentication; /* Try keyboard-interactive auth. */ diff --git a/servconf.c b/servconf.c index 873b0d02a..9b0628181 100644 --- a/servconf.c +++ b/servconf.c @@ -117,8 +117,10 @@ initialize_server_options(ServerOptions *options) options->kerberos_ticket_cleanup = -1; options->kerberos_get_afs_token = -1; options->gss_authentication=-1; + options->gss_keyex = -1; options->gss_cleanup_creds = -1; options->gss_strict_acceptor = -1; + options->gss_store_rekey = -1; options->password_authentication = -1; options->kbd_interactive_authentication = -1; options->challenge_response_authentication = -1; @@ -287,10 +289,14 @@ fill_default_server_options(ServerOptions *options) options->kerberos_get_afs_token = 0; if (options->gss_authentication == -1) options->gss_authentication = 0; + if (options->gss_keyex == -1) + options->gss_keyex = 0; if (options->gss_cleanup_creds == -1) options->gss_cleanup_creds = 1; if (options->gss_strict_acceptor == -1) - options->gss_strict_acceptor = 0; + options->gss_strict_acceptor = 1; + if (options->gss_store_rekey == -1) + options->gss_store_rekey = 0; if (options->password_authentication == -1) options->password_authentication = 1; if (options->kbd_interactive_authentication == -1) @@ -427,6 +433,7 @@ typedef enum { sHostKeyAlgorithms, sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile, sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor, + sGssKeyEx, sGssStoreRekey, sAcceptEnv, sPermitTunnel, sMatch, sPermitOpen, sForceCommand, sChrootDirectory, sUsePrivilegeSeparation, sAllowAgentForwarding, @@ -500,12 +507,20 @@ static struct { #ifdef GSSAPI { "gssapiauthentication", sGssAuthentication, SSHCFG_ALL }, { "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL }, + { "gssapicleanupcreds", sGssCleanupCreds, SSHCFG_GLOBAL }, { "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL }, + { "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL }, + { "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL }, #else { "gssapiauthentication", sUnsupported, SSHCFG_ALL }, { "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL }, + { "gssapicleanupcreds", sUnsupported, SSHCFG_GLOBAL }, { "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL }, + { "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL }, + { "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL }, #endif + { "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL }, + { "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL }, { "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL }, { "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL }, { "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL }, @@ -1251,6 +1266,10 @@ process_server_config_line(ServerOptions *options, char *line, intptr = &options->gss_authentication; goto parse_flag; + case sGssKeyEx: + intptr = &options->gss_keyex; + goto parse_flag; + case sGssCleanupCreds: intptr = &options->gss_cleanup_creds; goto parse_flag; @@ -1259,6 +1278,10 @@ process_server_config_line(ServerOptions *options, char *line, intptr = &options->gss_strict_acceptor; goto parse_flag; + case sGssStoreRekey: + intptr = &options->gss_store_rekey; + goto parse_flag; + case sPasswordAuthentication: intptr = &options->password_authentication; goto parse_flag; @@ -2308,7 +2331,10 @@ dump_config(ServerOptions *o) #endif #ifdef GSSAPI dump_cfg_fmtint(sGssAuthentication, o->gss_authentication); + dump_cfg_fmtint(sGssKeyEx, o->gss_keyex); dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds); + dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor); + dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey); #endif dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication); dump_cfg_fmtint(sKbdInteractiveAuthentication, diff --git a/servconf.h b/servconf.h index f4137af7d..778ba1742 100644 --- a/servconf.h +++ b/servconf.h @@ -118,8 +118,10 @@ typedef struct { int kerberos_get_afs_token; /* If true, try to get AFS token if * authenticated with Kerberos. */ int gss_authentication; /* If true, permit GSSAPI authentication */ + int gss_keyex; /* If true, permit GSSAPI key exchange */ int gss_cleanup_creds; /* If true, destroy cred cache on logout */ int gss_strict_acceptor; /* If true, restrict the GSSAPI acceptor name */ + int gss_store_rekey; int password_authentication; /* If true, permit password * authentication. */ int kbd_interactive_authentication; /* If true, permit */ diff --git a/ssh-gss.h b/ssh-gss.h index a99d7f08b..914701bcf 100644 --- a/ssh-gss.h +++ b/ssh-gss.h @@ -1,6 +1,6 @@ /* $OpenBSD: ssh-gss.h,v 1.11 2014/02/26 20:28:44 djm Exp $ */ /* - * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved. + * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -61,10 +61,22 @@ #define SSH_GSS_OIDTYPE 0x06 +#define SSH2_MSG_KEXGSS_INIT 30 +#define SSH2_MSG_KEXGSS_CONTINUE 31 +#define SSH2_MSG_KEXGSS_COMPLETE 32 +#define SSH2_MSG_KEXGSS_HOSTKEY 33 +#define SSH2_MSG_KEXGSS_ERROR 34 +#define SSH2_MSG_KEXGSS_GROUPREQ 40 +#define SSH2_MSG_KEXGSS_GROUP 41 +#define KEX_GSS_GRP1_SHA1_ID "gss-group1-sha1-" +#define KEX_GSS_GRP14_SHA1_ID "gss-group14-sha1-" +#define KEX_GSS_GEX_SHA1_ID "gss-gex-sha1-" + typedef struct { char *filename; char *envvar; char *envval; + struct passwd *owner; void *data; } ssh_gssapi_ccache; @@ -72,8 +84,11 @@ typedef struct { gss_buffer_desc displayname; gss_buffer_desc exportedname; gss_cred_id_t creds; + gss_name_t name; struct ssh_gssapi_mech_struct *mech; ssh_gssapi_ccache store; + int used; + int updated; } ssh_gssapi_client; typedef struct ssh_gssapi_mech_struct { @@ -84,6 +99,7 @@ typedef struct ssh_gssapi_mech_struct { int (*userok) (ssh_gssapi_client *, char *); int (*localname) (ssh_gssapi_client *, char **); void (*storecreds) (ssh_gssapi_client *); + int (*updatecreds) (ssh_gssapi_ccache *, ssh_gssapi_client *); } ssh_gssapi_mech; typedef struct { @@ -94,10 +110,11 @@ typedef struct { gss_OID oid; /* client */ gss_cred_id_t creds; /* server */ gss_name_t client; /* server */ - gss_cred_id_t client_creds; /* server */ + gss_cred_id_t client_creds; /* both */ } Gssctxt; extern ssh_gssapi_mech *supported_mechs[]; +extern Gssctxt *gss_kex_context; int ssh_gssapi_check_oid(Gssctxt *, void *, size_t); void ssh_gssapi_set_oid_data(Gssctxt *, void *, size_t); @@ -119,16 +136,32 @@ void ssh_gssapi_build_ctx(Gssctxt **); void ssh_gssapi_delete_ctx(Gssctxt **); OM_uint32 ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t); void ssh_gssapi_buildmic(Buffer *, const char *, const char *, const char *); -int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *); +int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *, const char *); +OM_uint32 ssh_gssapi_client_identity(Gssctxt *, const char *); +int ssh_gssapi_credentials_updated(Gssctxt *); /* In the server */ +typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *, + const char *); +char *ssh_gssapi_client_mechanisms(const char *, const char *); +char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *, + const char *); +gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int); +int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *, + const char *); OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID); -int ssh_gssapi_userok(char *name); +int ssh_gssapi_userok(char *name, struct passwd *); OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t); void ssh_gssapi_do_child(char ***, u_int *); void ssh_gssapi_cleanup_creds(void); void ssh_gssapi_storecreds(void); +char *ssh_gssapi_server_mechanisms(void); +int ssh_gssapi_oid_table_ok(void); + +int ssh_gssapi_update_creds(ssh_gssapi_ccache *store); +void ssh_gssapi_rekey_creds(void); + #endif /* GSSAPI */ #endif /* _SSH_GSS_H */ diff --git a/ssh_config b/ssh_config index 90fb63f0b..4e879cd20 100644 --- a/ssh_config +++ b/ssh_config @@ -26,6 +26,8 @@ # HostbasedAuthentication no # GSSAPIAuthentication no # GSSAPIDelegateCredentials no +# GSSAPIKeyExchange no +# GSSAPITrustDNS no # BatchMode no # CheckHostIP yes # AddressFamily any diff --git a/ssh_config.5 b/ssh_config.5 index 7630e7bcb..707d0e1c3 100644 --- a/ssh_config.5 +++ b/ssh_config.5 @@ -826,10 +826,42 @@ The default is Specifies whether user authentication based on GSSAPI is allowed. The default is .Dq no . +.It Cm GSSAPIKeyExchange +Specifies whether key exchange based on GSSAPI may be used. When using +GSSAPI key exchange the server need not have a host key. +The default is +.Dq no . +.It Cm GSSAPIClientIdentity +If set, specifies the GSSAPI client identity that ssh should use when +connecting to the server. The default is unset, which means that the default +identity will be used. +.It Cm GSSAPIServerIdentity +If set, specifies the GSSAPI server identity that ssh should expect when +connecting to the server. The default is unset, which means that the +expected GSSAPI server identity will be determined from the target +hostname. .It Cm GSSAPIDelegateCredentials Forward (delegate) credentials to the server. The default is .Dq no . +.It Cm GSSAPIRenewalForcesRekey +If set to +.Dq yes +then renewal of the client's GSSAPI credentials will force the rekeying of the +ssh connection. With a compatible server, this can delegate the renewed +credentials to a session on the server. +The default is +.Dq no . +.It Cm GSSAPITrustDns +Set to +.Dq yes +to indicate that the DNS is trusted to securely canonicalize +the name of the host being connected to. If +.Dq no , +the hostname entered on the +command line will be passed untouched to the GSSAPI library. +The default is +.Dq no . .It Cm HashKnownHosts Indicates that .Xr ssh 1 diff --git a/sshconnect2.c b/sshconnect2.c index fae8b0f2c..34b9d304e 100644 --- a/sshconnect2.c +++ b/sshconnect2.c @@ -162,6 +162,11 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) struct kex *kex; int r; +#ifdef GSSAPI + char *orig = NULL, *gss = NULL; + char *gss_host = NULL; +#endif + xxx_host = host; xxx_hostaddr = hostaddr; @@ -192,6 +197,36 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) order_hostkeyalgs(host, hostaddr, port)); } +#ifdef GSSAPI + if (options.gss_keyex) { + /* Add the GSSAPI mechanisms currently supported on this + * client to the key exchange algorithm proposal */ + orig = myproposal[PROPOSAL_KEX_ALGS]; + + if (options.gss_server_identity) + gss_host = xstrdup(options.gss_server_identity); + else if (options.gss_trust_dns) + gss_host = remote_hostname(active_state); + else + gss_host = xstrdup(host); + + gss = ssh_gssapi_client_mechanisms(gss_host, + options.gss_client_identity); + if (gss) { + debug("Offering GSSAPI proposal: %s", gss); + xasprintf(&myproposal[PROPOSAL_KEX_ALGS], + "%s,%s", gss, orig); + + /* If we've got GSSAPI algorithms, then we also + * support the 'null' hostkey, as a last resort */ + orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; + xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], + "%s,null", orig); + free(gss); + } + } +#endif + if (options.rekey_limit || options.rekey_interval) packet_set_rekey_limits((u_int32_t)options.rekey_limit, (time_t)options.rekey_interval); @@ -213,10 +248,26 @@ ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) # endif #endif kex->kex[KEX_C25519_SHA256] = kexc25519_client; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; + } +#endif kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; kex->verify_host_key=&verify_host_key_callback; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->gss_deleg_creds = options.gss_deleg_creds; + kex->gss_trust_dns = options.gss_trust_dns; + kex->gss_client = options.gss_client_identity; + kex->gss_host = gss_host; + } +#endif + dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); /* remove ext-info from the KEX proposals for rekeying */ @@ -311,6 +362,7 @@ int input_gssapi_token(int type, u_int32_t, void *); int input_gssapi_hash(int type, u_int32_t, void *); int input_gssapi_error(int, u_int32_t, void *); int input_gssapi_errtok(int, u_int32_t, void *); +int userauth_gsskeyex(Authctxt *authctxt); #endif void userauth(Authctxt *, char *); @@ -326,6 +378,11 @@ static char *authmethods_get(void); Authmethod authmethods[] = { #ifdef GSSAPI + {"gssapi-keyex", + userauth_gsskeyex, + NULL, + &options.gss_authentication, + NULL}, {"gssapi-with-mic", userauth_gssapi, NULL, @@ -650,25 +707,40 @@ userauth_gssapi(Authctxt *authctxt) static u_int mech = 0; OM_uint32 min; int ok = 0; + char *gss_host; + + if (options.gss_server_identity) + gss_host = xstrdup(options.gss_server_identity); + else if (options.gss_trust_dns) + gss_host = remote_hostname(active_state); + else + gss_host = xstrdup(authctxt->host); /* Try one GSSAPI method at a time, rather than sending them all at * once. */ if (gss_supported == NULL) - gss_indicate_mechs(&min, &gss_supported); + if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) { + gss_supported = NULL; + free(gss_host); + return 0; + } /* Check to see if the mechanism is usable before we offer it */ while (mech < gss_supported->count && !ok) { /* My DER encoding requires length<128 */ if (gss_supported->elements[mech].length < 128 && ssh_gssapi_check_mechanism(&gssctxt, - &gss_supported->elements[mech], authctxt->host)) { + &gss_supported->elements[mech], gss_host, + options.gss_client_identity)) { ok = 1; /* Mechanism works */ } else { mech++; } } + free(gss_host); + if (!ok) return 0; @@ -759,8 +831,8 @@ input_gssapi_response(int type, u_int32_t plen, void *ctxt) { Authctxt *authctxt = ctxt; Gssctxt *gssctxt; - int oidlen; - char *oidv; + u_int oidlen; + u_char *oidv; if (authctxt == NULL) fatal("input_gssapi_response: no authentication context"); @@ -873,6 +945,48 @@ input_gssapi_error(int type, u_int32_t plen, void *ctxt) free(lang); return 0; } + +int +userauth_gsskeyex(Authctxt *authctxt) +{ + Buffer b; + gss_buffer_desc gssbuf; + gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; + OM_uint32 ms; + + static int attempt = 0; + if (attempt++ >= 1) + return (0); + + if (gss_kex_context == NULL) { + debug("No valid Key exchange context"); + return (0); + } + + ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, + "gssapi-keyex"); + + gssbuf.value = buffer_ptr(&b); + gssbuf.length = buffer_len(&b); + + if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { + buffer_free(&b); + return (0); + } + + packet_start(SSH2_MSG_USERAUTH_REQUEST); + packet_put_cstring(authctxt->server_user); + packet_put_cstring(authctxt->service); + packet_put_cstring(authctxt->method->name); + packet_put_string(mic.value, mic.length); + packet_send(); + + buffer_free(&b); + gss_release_buffer(&ms, &mic); + + return (1); +} + #endif /* GSSAPI */ int diff --git a/sshd.c b/sshd.c index 799c7711f..ebb88c776 100644 --- a/sshd.c +++ b/sshd.c @@ -125,6 +125,10 @@ #include "version.h" #include "ssherr.h" +#ifdef USE_SECURITY_SESSION_API +#include +#endif + #ifndef O_NOCTTY #define O_NOCTTY 0 #endif @@ -1892,10 +1896,13 @@ main(int ac, char **av) logit("Disabling protocol version 1. Could not load host key"); options.protocol &= ~SSH_PROTO_1; } +#ifndef GSSAPI + /* The GSSAPI key exchange can run without a host key */ if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { logit("Disabling protocol version 2. Could not load host key"); options.protocol &= ~SSH_PROTO_2; } +#endif if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { logit("sshd: no hostkeys available -- exiting."); exit(1); @@ -2207,6 +2214,60 @@ main(int ac, char **av) remote_ip, remote_port, laddr, ssh_local_port(ssh)); free(laddr); +#ifdef USE_SECURITY_SESSION_API + /* + * Create a new security session for use by the new user login if + * the current session is the root session or we are not launched + * by inetd (eg: debugging mode or server mode). We do not + * necessarily need to create a session if we are launched from + * inetd because Panther xinetd will create a session for us. + * + * The only case where this logic will fail is if there is an + * inetd running in a non-root session which is not creating + * new sessions for us. Then all the users will end up in the + * same session (bad). + * + * When the client exits, the session will be destroyed for us + * automatically. + * + * We must create the session before any credentials are stored + * (including AFS pags, which happens a few lines below). + */ + { + OSStatus err = 0; + SecuritySessionId sid = 0; + SessionAttributeBits sattrs = 0; + + err = SessionGetInfo(callerSecuritySession, &sid, &sattrs); + if (err) + error("SessionGetInfo() failed with error %.8X", + (unsigned) err); + else + debug("Current Session ID is %.8X / Session Attributes are %.8X", + (unsigned) sid, (unsigned) sattrs); + + if (inetd_flag && !(sattrs & sessionIsRoot)) + debug("Running in inetd mode in a non-root session... " + "assuming inetd created the session for us."); + else { + debug("Creating new security session..."); + err = SessionCreate(0, sessionHasTTY | sessionIsRemote); + if (err) + error("SessionCreate() failed with error %.8X", + (unsigned) err); + + err = SessionGetInfo(callerSecuritySession, &sid, + &sattrs); + if (err) + error("SessionGetInfo() failed with error %.8X", + (unsigned) err); + else + debug("New Session ID is %.8X / Session Attributes are %.8X", + (unsigned) sid, (unsigned) sattrs); + } + } +#endif + /* * We don't want to listen forever unless the other side * successfully authenticates itself. So we set up an alarm which is @@ -2631,6 +2692,48 @@ do_ssh2_kex(void) myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal( list_hostkey_types()); +#ifdef GSSAPI + { + char *orig; + char *gss = NULL; + char *newstr = NULL; + orig = myproposal[PROPOSAL_KEX_ALGS]; + + /* + * If we don't have a host key, then there's no point advertising + * the other key exchange algorithms + */ + + if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0) + orig = NULL; + + if (options.gss_keyex) + gss = ssh_gssapi_server_mechanisms(); + else + gss = NULL; + + if (gss && orig) + xasprintf(&newstr, "%s,%s", gss, orig); + else if (gss) + newstr = gss; + else if (orig) + newstr = orig; + + /* + * If we've got GSSAPI mechanisms, then we've got the 'null' host + * key alg, but we can't tell people about it unless its the only + * host key algorithm we support + */ + if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0) + myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = "null"; + + if (newstr) + myproposal[PROPOSAL_KEX_ALGS] = newstr; + else + fatal("No supported key exchange algorithms"); + } +#endif + /* start key exchange */ if ((r = kex_setup(active_state, myproposal)) != 0) fatal("kex_setup: %s", ssh_err(r)); @@ -2648,6 +2751,13 @@ do_ssh2_kex(void) # endif #endif kex->kex[KEX_C25519_SHA256] = kexc25519_server; +#ifdef GSSAPI + if (options.gss_keyex) { + kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server; + kex->kex[KEX_GSS_GEX_SHA1] = kexgss_server; + } +#endif kex->server = 1; kex->client_version_string=client_version_string; kex->server_version_string=server_version_string; diff --git a/sshd_config b/sshd_config index 75ae8e739..3fe3e017e 100644 --- a/sshd_config +++ b/sshd_config @@ -83,6 +83,8 @@ AuthorizedKeysFile .ssh/authorized_keys # GSSAPI options #GSSAPIAuthentication no #GSSAPICleanupCredentials yes +#GSSAPIStrictAcceptorCheck yes +#GSSAPIKeyExchange no # Set this to 'yes' to enable PAM authentication, account processing, # and session processing. If this is enabled, PAM authentication will diff --git a/sshd_config.5 b/sshd_config.5 index 1bc26ec4d..3b4cba9ae 100644 --- a/sshd_config.5 +++ b/sshd_config.5 @@ -632,6 +632,11 @@ The default is Specifies whether user authentication based on GSSAPI is allowed. The default is .Dq no . +.It Cm GSSAPIKeyExchange +Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange +doesn't rely on ssh keys to verify host identity. +The default is +.Dq no . .It Cm GSSAPICleanupCredentials Specifies whether to automatically destroy the user's credentials cache on logout. @@ -652,6 +657,11 @@ machine's default store. This facility is provided to assist with operation on multi homed machines. The default is .Dq yes . +.It Cm GSSAPIStoreCredentialsOnRekey +Controls whether the user's GSSAPI credentials should be updated following a +successful connection rekeying. This option can be used to accepted renewed +or updated credentials from a compatible client. The default is +.Dq no . .It Cm HostbasedAcceptedKeyTypes Specifies the key types that will be accepted for hostbased authentication as a comma-separated pattern list. diff --git a/sshkey.c b/sshkey.c index c9f04cd67..558bbbef6 100644 --- a/sshkey.c +++ b/sshkey.c @@ -115,6 +115,7 @@ static const struct keytype keytypes[] = { # endif /* OPENSSL_HAS_NISTP521 */ # endif /* OPENSSL_HAS_ECC */ #endif /* WITH_OPENSSL */ + { "null", "null", KEY_NULL, 0, 0, 0 }, { NULL, NULL, -1, -1, 0, 0 } }; @@ -203,7 +204,7 @@ key_alg_list(int certs_only, int plain_only) const struct keytype *kt; for (kt = keytypes; kt->type != -1; kt++) { - if (kt->name == NULL || kt->sigonly) + if (kt->name == NULL || kt->sigonly || kt->type == KEY_NULL) continue; if ((certs_only && !kt->cert) || (plain_only && kt->cert)) continue; diff --git a/sshkey.h b/sshkey.h index 8c3d866bf..e0caa37a7 100644 --- a/sshkey.h +++ b/sshkey.h @@ -62,6 +62,7 @@ enum sshkey_types { KEY_DSA_CERT, KEY_ECDSA_CERT, KEY_ED25519_CERT, + KEY_NULL, KEY_UNSPEC }; -- cgit v1.2.3 From 7a7851c903e5dbb58a85014deb2c88cb718068c9 Mon Sep 17 00:00:00 2001 From: Manoj Srivastava Date: Sun, 9 Feb 2014 16:09:49 +0000 Subject: Handle SELinux authorisation roles Rejected upstream due to discomfort with magic usernames; a better approach will need an SSH protocol change. In the meantime, this came from Debian's SELinux maintainer, so we'll keep it until we have something better. Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1641 Bug-Debian: http://bugs.debian.org/394795 Last-Update: 2015-08-19 Patch-Name: selinux-role.patch --- auth.h | 1 + auth1.c | 8 +++++++- auth2.c | 10 ++++++++-- monitor.c | 32 +++++++++++++++++++++++++++++--- monitor.h | 2 ++ monitor_wrap.c | 22 ++++++++++++++++++++-- monitor_wrap.h | 3 ++- openbsd-compat/port-linux.c | 27 ++++++++++++++++++++------- openbsd-compat/port-linux.h | 4 ++-- platform.c | 4 ++-- platform.h | 2 +- session.c | 10 +++++----- session.h | 2 +- sshd.c | 2 +- sshpty.c | 4 ++-- sshpty.h | 2 +- 16 files changed, 104 insertions(+), 31 deletions(-) (limited to 'monitor_wrap.c') diff --git a/auth.h b/auth.h index 55170af50..50baeaadb 100644 --- a/auth.h +++ b/auth.h @@ -62,6 +62,7 @@ struct Authctxt { char *service; struct passwd *pw; /* set if 'valid' */ char *style; + char *role; void *kbdintctxt; char *info; /* Extra info for next auth_log */ #ifdef BSD_AUTH diff --git a/auth1.c b/auth1.c index 5073c49bb..dd0064832 100644 --- a/auth1.c +++ b/auth1.c @@ -383,7 +383,7 @@ void do_authentication(Authctxt *authctxt) { u_int ulen; - char *user, *style = NULL; + char *user, *style = NULL, *role = NULL; /* Get the name of the user that we wish to log in as. */ packet_read_expect(SSH_CMSG_USER); @@ -392,11 +392,17 @@ do_authentication(Authctxt *authctxt) user = packet_get_cstring(&ulen); packet_check_eom(); + if ((role = strchr(user, '/')) != NULL) + *role++ = '\0'; + if ((style = strchr(user, ':')) != NULL) *style++ = '\0'; + else if (role && (style = strchr(role, ':')) != NULL) + *style++ = '\0'; authctxt->user = user; authctxt->style = style; + authctxt->role = role; /* Verify that the user is a valid user. */ if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL) diff --git a/auth2.c b/auth2.c index ce0d37601..461311bda 100644 --- a/auth2.c +++ b/auth2.c @@ -216,7 +216,7 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt) { Authctxt *authctxt = ctxt; Authmethod *m = NULL; - char *user, *service, *method, *style = NULL; + char *user, *service, *method, *style = NULL, *role = NULL; int authenticated = 0; if (authctxt == NULL) @@ -228,8 +228,13 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt) debug("userauth-request for user %s service %s method %s", user, service, method); debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); + if ((role = strchr(user, '/')) != NULL) + *role++ = 0; + if ((style = strchr(user, ':')) != NULL) *style++ = 0; + else if (role && (style = strchr(role, ':')) != NULL) + *style++ = '\0'; if (authctxt->attempt++ == 0) { /* setup auth context */ @@ -253,8 +258,9 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt) use_privsep ? " [net]" : ""); authctxt->service = xstrdup(service); authctxt->style = style ? xstrdup(style) : NULL; + authctxt->role = role ? xstrdup(role) : NULL; if (use_privsep) - mm_inform_authserv(service, style); + mm_inform_authserv(service, style, role); userauth_banner(); if (auth2_setup_methods_lists(authctxt) != 0) packet_disconnect("no authentication methods enabled"); diff --git a/monitor.c b/monitor.c index 05bb48a8e..e91054e5f 100644 --- a/monitor.c +++ b/monitor.c @@ -128,6 +128,7 @@ int mm_answer_sign(int, Buffer *); int mm_answer_pwnamallow(int, Buffer *); int mm_answer_auth2_read_banner(int, Buffer *); int mm_answer_authserv(int, Buffer *); +int mm_answer_authrole(int, Buffer *); int mm_answer_authpassword(int, Buffer *); int mm_answer_bsdauthquery(int, Buffer *); int mm_answer_bsdauthrespond(int, Buffer *); @@ -209,6 +210,7 @@ struct mon_table mon_dispatch_proto20[] = { {MONITOR_REQ_SIGN, MON_ONCE, mm_answer_sign}, {MONITOR_REQ_PWNAM, MON_ONCE, mm_answer_pwnamallow}, {MONITOR_REQ_AUTHSERV, MON_ONCE, mm_answer_authserv}, + {MONITOR_REQ_AUTHROLE, MON_ONCE, mm_answer_authrole}, {MONITOR_REQ_AUTH2_READ_BANNER, MON_ONCE, mm_answer_auth2_read_banner}, {MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword}, #ifdef USE_PAM @@ -880,6 +882,7 @@ mm_answer_pwnamallow(int sock, Buffer *m) else { /* Allow service/style information on the auth context */ monitor_permit(mon_dispatch, MONITOR_REQ_AUTHSERV, 1); + monitor_permit(mon_dispatch, MONITOR_REQ_AUTHROLE, 1); monitor_permit(mon_dispatch, MONITOR_REQ_AUTH2_READ_BANNER, 1); } #ifdef USE_PAM @@ -910,14 +913,37 @@ mm_answer_authserv(int sock, Buffer *m) authctxt->service = buffer_get_string(m, NULL); authctxt->style = buffer_get_string(m, NULL); - debug3("%s: service=%s, style=%s", - __func__, authctxt->service, authctxt->style); + authctxt->role = buffer_get_string(m, NULL); + debug3("%s: service=%s, style=%s, role=%s", + __func__, authctxt->service, authctxt->style, authctxt->role); if (strlen(authctxt->style) == 0) { free(authctxt->style); authctxt->style = NULL; } + if (strlen(authctxt->role) == 0) { + free(authctxt->role); + authctxt->role = NULL; + } + + return (0); +} + +int +mm_answer_authrole(int sock, Buffer *m) +{ + monitor_permit_authentications(1); + + authctxt->role = buffer_get_string(m, NULL); + debug3("%s: role=%s", + __func__, authctxt->role); + + if (strlen(authctxt->role) == 0) { + free(authctxt->role); + authctxt->role = NULL; + } + return (0); } @@ -1553,7 +1579,7 @@ mm_answer_pty(int sock, Buffer *m) res = pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty)); if (res == 0) goto error; - pty_setowner(authctxt->pw, s->tty); + pty_setowner(authctxt->pw, s->tty, authctxt->role); buffer_put_int(m, 1); buffer_put_cstring(m, s->tty); diff --git a/monitor.h b/monitor.h index bc50ade1f..2d82b8b84 100644 --- a/monitor.h +++ b/monitor.h @@ -68,6 +68,8 @@ enum monitor_reqtype { MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151, MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153, + MONITOR_REQ_AUTHROLE = 154, + }; struct mm_master; diff --git a/monitor_wrap.c b/monitor_wrap.c index 5a9f1b52d..11e3a6956 100644 --- a/monitor_wrap.c +++ b/monitor_wrap.c @@ -328,10 +328,10 @@ mm_auth2_read_banner(void) return (banner); } -/* Inform the privileged process about service and style */ +/* Inform the privileged process about service, style, and role */ void -mm_inform_authserv(char *service, char *style) +mm_inform_authserv(char *service, char *style, char *role) { Buffer m; @@ -340,12 +340,30 @@ mm_inform_authserv(char *service, char *style) buffer_init(&m); buffer_put_cstring(&m, service); buffer_put_cstring(&m, style ? style : ""); + buffer_put_cstring(&m, role ? role : ""); mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, &m); buffer_free(&m); } +/* Inform the privileged process about role */ + +void +mm_inform_authrole(char *role) +{ + Buffer m; + + debug3("%s entering", __func__); + + buffer_init(&m); + buffer_put_cstring(&m, role ? role : ""); + + mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHROLE, &m); + + buffer_free(&m); +} + /* Do the password authentication */ int mm_auth_password(Authctxt *authctxt, char *password) diff --git a/monitor_wrap.h b/monitor_wrap.h index b5414c298..d5b3334dc 100644 --- a/monitor_wrap.h +++ b/monitor_wrap.h @@ -41,7 +41,8 @@ void mm_log_handler(LogLevel, const char *, void *); int mm_is_monitor(void); DH *mm_choose_dh(int, int, int); int mm_key_sign(Key *, u_char **, u_int *, const u_char *, u_int, const char *); -void mm_inform_authserv(char *, char *); +void mm_inform_authserv(char *, char *, char *); +void mm_inform_authrole(char *); struct passwd *mm_getpwnamallow(const char *); char *mm_auth2_read_banner(void); int mm_auth_password(struct Authctxt *, char *); diff --git a/openbsd-compat/port-linux.c b/openbsd-compat/port-linux.c index f36999d7a..f9cdc15c3 100644 --- a/openbsd-compat/port-linux.c +++ b/openbsd-compat/port-linux.c @@ -29,6 +29,12 @@ #include #include +#ifdef WITH_SELINUX +#include "key.h" +#include "hostfile.h" +#include "auth.h" +#endif + #include "log.h" #include "xmalloc.h" #include "port-linux.h" @@ -58,7 +64,7 @@ ssh_selinux_enabled(void) /* Return the default security context for the given username */ static security_context_t -ssh_selinux_getctxbyname(char *pwname) +ssh_selinux_getctxbyname(char *pwname, const char *role) { security_context_t sc = NULL; char *sename = NULL, *lvl = NULL; @@ -73,9 +79,16 @@ ssh_selinux_getctxbyname(char *pwname) #endif #ifdef HAVE_GET_DEFAULT_CONTEXT_WITH_LEVEL - r = get_default_context_with_level(sename, lvl, NULL, &sc); + if (role != NULL && role[0]) + r = get_default_context_with_rolelevel(sename, role, lvl, NULL, + &sc); + else + r = get_default_context_with_level(sename, lvl, NULL, &sc); #else - r = get_default_context(sename, NULL, &sc); + if (role != NULL && role[0]) + r = get_default_context_with_role(sename, role, NULL, &sc); + else + r = get_default_context(sename, NULL, &sc); #endif if (r != 0) { @@ -105,7 +118,7 @@ ssh_selinux_getctxbyname(char *pwname) /* Set the execution context to the default for the specified user */ void -ssh_selinux_setup_exec_context(char *pwname) +ssh_selinux_setup_exec_context(char *pwname, const char *role) { security_context_t user_ctx = NULL; @@ -114,7 +127,7 @@ ssh_selinux_setup_exec_context(char *pwname) debug3("%s: setting execution context", __func__); - user_ctx = ssh_selinux_getctxbyname(pwname); + user_ctx = ssh_selinux_getctxbyname(pwname, role); if (setexeccon(user_ctx) != 0) { switch (security_getenforce()) { case -1: @@ -136,7 +149,7 @@ ssh_selinux_setup_exec_context(char *pwname) /* Set the TTY context for the specified user */ void -ssh_selinux_setup_pty(char *pwname, const char *tty) +ssh_selinux_setup_pty(char *pwname, const char *tty, const char *role) { security_context_t new_tty_ctx = NULL; security_context_t user_ctx = NULL; @@ -147,7 +160,7 @@ ssh_selinux_setup_pty(char *pwname, const char *tty) debug3("%s: setting TTY context on %s", __func__, tty); - user_ctx = ssh_selinux_getctxbyname(pwname); + user_ctx = ssh_selinux_getctxbyname(pwname, role); /* XXX: should these calls fatal() upon failure in enforcing mode? */ diff --git a/openbsd-compat/port-linux.h b/openbsd-compat/port-linux.h index e3d1004aa..80ce13ad9 100644 --- a/openbsd-compat/port-linux.h +++ b/openbsd-compat/port-linux.h @@ -21,8 +21,8 @@ #ifdef WITH_SELINUX int ssh_selinux_enabled(void); -void ssh_selinux_setup_pty(char *, const char *); -void ssh_selinux_setup_exec_context(char *); +void ssh_selinux_setup_pty(char *, const char *, const char *); +void ssh_selinux_setup_exec_context(char *, const char *); void ssh_selinux_change_context(const char *); void ssh_selinux_setfscreatecon(const char *); #endif diff --git a/platform.c b/platform.c index acf8554cd..483170680 100644 --- a/platform.c +++ b/platform.c @@ -145,7 +145,7 @@ platform_setusercontext(struct passwd *pw) * called if sshd is running as root. */ void -platform_setusercontext_post_groups(struct passwd *pw) +platform_setusercontext_post_groups(struct passwd *pw, const char *role) { #if !defined(HAVE_LOGIN_CAP) && defined(USE_PAM) /* @@ -186,7 +186,7 @@ platform_setusercontext_post_groups(struct passwd *pw) } #endif /* HAVE_SETPCRED */ #ifdef WITH_SELINUX - ssh_selinux_setup_exec_context(pw->pw_name); + ssh_selinux_setup_exec_context(pw->pw_name, role); #endif } diff --git a/platform.h b/platform.h index e97ecd909..5b7230428 100644 --- a/platform.h +++ b/platform.h @@ -27,7 +27,7 @@ void platform_post_fork_parent(pid_t child_pid); void platform_post_fork_child(void); int platform_privileged_uidswap(void); void platform_setusercontext(struct passwd *); -void platform_setusercontext_post_groups(struct passwd *); +void platform_setusercontext_post_groups(struct passwd *, const char *); char *platform_get_krb5_client(const char *); char *platform_krb5_get_principal_name(const char *); int platform_sys_dir_uid(uid_t); diff --git a/session.c b/session.c index 2235f26ac..6dfcf842f 100644 --- a/session.c +++ b/session.c @@ -1517,7 +1517,7 @@ safely_chroot(const char *path, uid_t uid) /* Set login name, uid, gid, and groups. */ void -do_setusercontext(struct passwd *pw) +do_setusercontext(struct passwd *pw, const char *role) { char *chroot_path, *tmp; @@ -1545,7 +1545,7 @@ do_setusercontext(struct passwd *pw) endgrent(); #endif - platform_setusercontext_post_groups(pw); + platform_setusercontext_post_groups(pw, role); if (!in_chroot && options.chroot_directory != NULL && strcasecmp(options.chroot_directory, "none") != 0) { @@ -1703,7 +1703,7 @@ do_child(Session *s, const char *command) /* Force a password change */ if (s->authctxt->force_pwchange) { - do_setusercontext(pw); + do_setusercontext(pw, s->authctxt->role); child_close_fds(); do_pwchange(s); exit(1); @@ -1730,7 +1730,7 @@ do_child(Session *s, const char *command) /* When PAM is enabled we rely on it to do the nologin check */ if (!options.use_pam) do_nologin(pw); - do_setusercontext(pw); + do_setusercontext(pw, s->authctxt->role); /* * PAM session modules in do_setusercontext may have * generated messages, so if this in an interactive @@ -2141,7 +2141,7 @@ session_pty_req(Session *s) tty_parse_modes(s->ttyfd, &n_bytes); if (!use_privsep) - pty_setowner(s->pw, s->tty); + pty_setowner(s->pw, s->tty, s->authctxt->role); /* Set window size from the packet. */ pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); diff --git a/session.h b/session.h index f18eaf329..2b7d939c8 100644 --- a/session.h +++ b/session.h @@ -77,7 +77,7 @@ void session_pty_cleanup2(Session *); Session *session_new(void); Session *session_by_tty(char *); void session_close(Session *); -void do_setusercontext(struct passwd *); +void do_setusercontext(struct passwd *, const char *); void child_set_env(char ***envp, u_int *envsizep, const char *name, const char *value); diff --git a/sshd.c b/sshd.c index 982e5455e..76306da24 100644 --- a/sshd.c +++ b/sshd.c @@ -787,7 +787,7 @@ privsep_postauth(Authctxt *authctxt) explicit_bzero(rnd, sizeof(rnd)); /* Drop privileges */ - do_setusercontext(authctxt->pw); + do_setusercontext(authctxt->pw, authctxt->role); skip: /* It is safe now to apply the key state */ diff --git a/sshpty.c b/sshpty.c index 15da8c649..e89efb74a 100644 --- a/sshpty.c +++ b/sshpty.c @@ -187,7 +187,7 @@ pty_change_window_size(int ptyfd, u_int row, u_int col, } void -pty_setowner(struct passwd *pw, const char *tty) +pty_setowner(struct passwd *pw, const char *tty, const char *role) { struct group *grp; gid_t gid; @@ -209,7 +209,7 @@ pty_setowner(struct passwd *pw, const char *tty) strerror(errno)); #ifdef WITH_SELINUX - ssh_selinux_setup_pty(pw->pw_name, tty); + ssh_selinux_setup_pty(pw->pw_name, tty, role); #endif if (st.st_uid != pw->pw_uid || st.st_gid != gid) { diff --git a/sshpty.h b/sshpty.h index cfa322480..edf24365f 100644 --- a/sshpty.h +++ b/sshpty.h @@ -24,4 +24,4 @@ int pty_allocate(int *, int *, char *, size_t); void pty_release(const char *); void pty_make_controlling_tty(int *, const char *); void pty_change_window_size(int, u_int, u_int, u_int, u_int); -void pty_setowner(struct passwd *, const char *); +void pty_setowner(struct passwd *, const char *, const char *); -- cgit v1.2.3