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-rw-r--r--auth-options.c1216
1 files changed, 704 insertions, 512 deletions
diff --git a/auth-options.c b/auth-options.c
index ccdd0b20a..b528c197a 100644
--- a/auth-options.c
+++ b/auth-options.c
@@ -1,13 +1,18 @@
1/* $OpenBSD: auth-options.c,v 1.74 2017/09/12 06:32:07 djm Exp $ */ 1/* $OpenBSD: auth-options.c,v 1.78 2018/03/14 05:35:40 djm Exp $ */
2/* 2/*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 2018 Damien Miller <djm@mindrot.org>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 *
5 * All rights reserved 5 * Permission to use, copy, modify, and distribute this software for any
6 * As far as I am concerned, the code I have written for this software 6 * purpose with or without fee is hereby granted, provided that the above
7 * can be used freely for any purpose. Any derived versions of this 7 * copyright notice and this permission notice appear in all copies.
8 * software must be clearly marked as such, and if the derived work is 8 *
9 * incompatible with the protocol description in the RFC file, it must be 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * called by a name other than "ssh" or "Secure Shell". 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
11 */ 16 */
12 17
13#include "includes.h" 18#include "includes.h"
@@ -19,99 +24,33 @@
19#include <string.h> 24#include <string.h>
20#include <stdio.h> 25#include <stdio.h>
21#include <stdarg.h> 26#include <stdarg.h>
27#include <ctype.h>
28#include <limits.h>
22 29
23#include "openbsd-compat/sys-queue.h" 30#include "openbsd-compat/sys-queue.h"
24 31
25#include "key.h" /* XXX for typedef */
26#include "buffer.h" /* XXX for typedef */
27#include "xmalloc.h" 32#include "xmalloc.h"
28#include "match.h"
29#include "ssherr.h" 33#include "ssherr.h"
30#include "log.h" 34#include "log.h"
31#include "canohost.h"
32#include "packet.h"
33#include "sshbuf.h" 35#include "sshbuf.h"
34#include "misc.h" 36#include "misc.h"
35#include "channels.h"
36#include "servconf.h"
37#include "sshkey.h" 37#include "sshkey.h"
38#include "match.h"
39#include "ssh2.h"
38#include "auth-options.h" 40#include "auth-options.h"
39#include "hostfile.h"
40#include "auth.h"
41
42/* Flags set authorized_keys flags */
43int no_port_forwarding_flag = 0;
44int no_agent_forwarding_flag = 0;
45int no_x11_forwarding_flag = 0;
46int no_pty_flag = 0;
47int no_user_rc = 0;
48int key_is_cert_authority = 0;
49
50/* "command=" option. */
51char *forced_command = NULL;
52
53/* "environment=" options. */
54struct envstring *custom_environment = NULL;
55
56/* "tunnel=" option. */
57int forced_tun_device = -1;
58
59/* "principals=" option. */
60char *authorized_principals = NULL;
61
62/* Throttle log messages. */
63int logged_from_hostip = 0;
64int logged_cert_hostip = 0;
65
66extern ServerOptions options;
67
68/* XXX refactor to be stateless */
69
70void
71auth_start_parse_options(void)
72{
73 logged_from_hostip = 0;
74 logged_cert_hostip = 0;
75}
76
77void
78auth_clear_options(void)
79{
80 struct ssh *ssh = active_state; /* XXX */
81
82 no_agent_forwarding_flag = 0;
83 no_port_forwarding_flag = 0;
84 no_pty_flag = 0;
85 no_x11_forwarding_flag = 0;
86 no_user_rc = 0;
87 key_is_cert_authority = 0;
88 while (custom_environment) {
89 struct envstring *ce = custom_environment;
90 custom_environment = ce->next;
91 free(ce->s);
92 free(ce);
93 }
94 free(forced_command);
95 forced_command = NULL;
96 free(authorized_principals);
97 authorized_principals = NULL;
98 forced_tun_device = -1;
99 channel_clear_permitted_opens(ssh);
100}
101 41
102/* 42/*
103 * Match flag 'opt' in *optsp, and if allow_negate is set then also match 43 * Match flag 'opt' in *optsp, and if allow_negate is set then also match
104 * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0 44 * 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0
105 * if negated option matches. 45 * if negated option matches.
106 * If the option or negated option matches, then *optsp is updated to 46 * If the option or negated option matches, then *optsp is updated to
107 * point to the first character after the option and, if 'msg' is not NULL 47 * point to the first character after the option.
108 * then a message based on it added via auth_debug_add().
109 */ 48 */
110static int 49static int
111match_flag(const char *opt, int allow_negate, char **optsp, const char *msg) 50opt_flag(const char *opt, int allow_negate, const char **optsp)
112{ 51{
113 size_t opt_len = strlen(opt); 52 size_t opt_len = strlen(opt);
114 char *opts = *optsp; 53 const char *opts = *optsp;
115 int negate = 0; 54 int negate = 0;
116 55
117 if (allow_negate && strncasecmp(opts, "no-", 3) == 0) { 56 if (allow_negate && strncasecmp(opts, "no-", 3) == 0) {
@@ -120,371 +59,92 @@ match_flag(const char *opt, int allow_negate, char **optsp, const char *msg)
120 } 59 }
121 if (strncasecmp(opts, opt, opt_len) == 0) { 60 if (strncasecmp(opts, opt, opt_len) == 0) {
122 *optsp = opts + opt_len; 61 *optsp = opts + opt_len;
123 if (msg != NULL) {
124 auth_debug_add("%s %s.", msg,
125 negate ? "disabled" : "enabled");
126 }
127 return negate ? 0 : 1; 62 return negate ? 0 : 1;
128 } 63 }
129 return -1; 64 return -1;
130} 65}
131 66
132/* 67static char *
133 * return 1 if access is granted, 0 if not. 68opt_dequote(const char **sp, const char **errstrp)
134 * side effect: sets key option flags
135 * XXX remove side effects; fill structure instead.
136 */
137int
138auth_parse_options(struct passwd *pw, char *opts, const char *file,
139 u_long linenum)
140{ 69{
141 struct ssh *ssh = active_state; /* XXX */ 70 const char *s = *sp;
142 const char *cp; 71 char *ret;
143 int i, r; 72 size_t i;
144 73
145 /* reset options */ 74 *errstrp = NULL;
146 auth_clear_options(); 75 if (*s != '"') {
76 *errstrp = "missing start quote";
77 return NULL;
78 }
79 s++;
80 if ((ret = malloc(strlen((s)) + 1)) == NULL) {
81 *errstrp = "memory allocation failed";
82 return NULL;
83 }
84 for (i = 0; *s != '\0' && *s != '"';) {
85 if (s[0] == '\\' && s[1] == '"')
86 s++;
87 ret[i++] = *s++;
88 }
89 if (*s == '\0') {
90 *errstrp = "missing end quote";
91 free(ret);
92 return NULL;
93 }
94 ret[i] = '\0';
95 s++;
96 *sp = s;
97 return ret;
98}
147 99
148 if (!opts) 100static int
101opt_match(const char **opts, const char *term)
102{
103 if (strncasecmp((*opts), term, strlen(term)) == 0 &&
104 (*opts)[strlen(term)] == '=') {
105 *opts += strlen(term) + 1;
149 return 1; 106 return 1;
150
151 while (*opts && *opts != ' ' && *opts != '\t') {
152 if ((r = match_flag("cert-authority", 0, &opts, NULL)) != -1) {
153 key_is_cert_authority = r;
154 goto next_option;
155 }
156 if ((r = match_flag("restrict", 0, &opts, NULL)) != -1) {
157 auth_debug_add("Key is restricted.");
158 no_port_forwarding_flag = 1;
159 no_agent_forwarding_flag = 1;
160 no_x11_forwarding_flag = 1;
161 no_pty_flag = 1;
162 no_user_rc = 1;
163 goto next_option;
164 }
165 if ((r = match_flag("port-forwarding", 1, &opts,
166 "Port forwarding")) != -1) {
167 no_port_forwarding_flag = r != 1;
168 goto next_option;
169 }
170 if ((r = match_flag("agent-forwarding", 1, &opts,
171 "Agent forwarding")) != -1) {
172 no_agent_forwarding_flag = r != 1;
173 goto next_option;
174 }
175 if ((r = match_flag("x11-forwarding", 1, &opts,
176 "X11 forwarding")) != -1) {
177 no_x11_forwarding_flag = r != 1;
178 goto next_option;
179 }
180 if ((r = match_flag("pty", 1, &opts,
181 "PTY allocation")) != -1) {
182 no_pty_flag = r != 1;
183 goto next_option;
184 }
185 if ((r = match_flag("user-rc", 1, &opts,
186 "User rc execution")) != -1) {
187 no_user_rc = r != 1;
188 goto next_option;
189 }
190 cp = "command=\"";
191 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
192 opts += strlen(cp);
193 free(forced_command);
194 forced_command = xmalloc(strlen(opts) + 1);
195 i = 0;
196 while (*opts) {
197 if (*opts == '"')
198 break;
199 if (*opts == '\\' && opts[1] == '"') {
200 opts += 2;
201 forced_command[i++] = '"';
202 continue;
203 }
204 forced_command[i++] = *opts++;
205 }
206 if (!*opts) {
207 debug("%.100s, line %lu: missing end quote",
208 file, linenum);
209 auth_debug_add("%.100s, line %lu: missing end quote",
210 file, linenum);
211 free(forced_command);
212 forced_command = NULL;
213 goto bad_option;
214 }
215 forced_command[i] = '\0';
216 auth_debug_add("Forced command.");
217 opts++;
218 goto next_option;
219 }
220 cp = "principals=\"";
221 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
222 opts += strlen(cp);
223 free(authorized_principals);
224 authorized_principals = xmalloc(strlen(opts) + 1);
225 i = 0;
226 while (*opts) {
227 if (*opts == '"')
228 break;
229 if (*opts == '\\' && opts[1] == '"') {
230 opts += 2;
231 authorized_principals[i++] = '"';
232 continue;
233 }
234 authorized_principals[i++] = *opts++;
235 }
236 if (!*opts) {
237 debug("%.100s, line %lu: missing end quote",
238 file, linenum);
239 auth_debug_add("%.100s, line %lu: missing end quote",
240 file, linenum);
241 free(authorized_principals);
242 authorized_principals = NULL;
243 goto bad_option;
244 }
245 authorized_principals[i] = '\0';
246 auth_debug_add("principals: %.900s",
247 authorized_principals);
248 opts++;
249 goto next_option;
250 }
251 cp = "environment=\"";
252 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
253 char *s;
254 struct envstring *new_envstring;
255
256 opts += strlen(cp);
257 s = xmalloc(strlen(opts) + 1);
258 i = 0;
259 while (*opts) {
260 if (*opts == '"')
261 break;
262 if (*opts == '\\' && opts[1] == '"') {
263 opts += 2;
264 s[i++] = '"';
265 continue;
266 }
267 s[i++] = *opts++;
268 }
269 if (!*opts) {
270 debug("%.100s, line %lu: missing end quote",
271 file, linenum);
272 auth_debug_add("%.100s, line %lu: missing end quote",
273 file, linenum);
274 free(s);
275 goto bad_option;
276 }
277 s[i] = '\0';
278 opts++;
279 if (options.permit_user_env) {
280 auth_debug_add("Adding to environment: "
281 "%.900s", s);
282 debug("Adding to environment: %.900s", s);
283 new_envstring = xcalloc(1,
284 sizeof(*new_envstring));
285 new_envstring->s = s;
286 new_envstring->next = custom_environment;
287 custom_environment = new_envstring;
288 s = NULL;
289 }
290 free(s);
291 goto next_option;
292 }
293 cp = "from=\"";
294 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
295 const char *remote_ip = ssh_remote_ipaddr(ssh);
296 const char *remote_host = auth_get_canonical_hostname(
297 ssh, options.use_dns);
298 char *patterns = xmalloc(strlen(opts) + 1);
299
300 opts += strlen(cp);
301 i = 0;
302 while (*opts) {
303 if (*opts == '"')
304 break;
305 if (*opts == '\\' && opts[1] == '"') {
306 opts += 2;
307 patterns[i++] = '"';
308 continue;
309 }
310 patterns[i++] = *opts++;
311 }
312 if (!*opts) {
313 debug("%.100s, line %lu: missing end quote",
314 file, linenum);
315 auth_debug_add("%.100s, line %lu: missing end quote",
316 file, linenum);
317 free(patterns);
318 goto bad_option;
319 }
320 patterns[i] = '\0';
321 opts++;
322 switch (match_host_and_ip(remote_host, remote_ip,
323 patterns)) {
324 case 1:
325 free(patterns);
326 /* Host name matches. */
327 goto next_option;
328 case -1:
329 debug("%.100s, line %lu: invalid criteria",
330 file, linenum);
331 auth_debug_add("%.100s, line %lu: "
332 "invalid criteria", file, linenum);
333 /* FALLTHROUGH */
334 case 0:
335 free(patterns);
336 if (!logged_from_hostip) {
337 logit("Authentication tried for %.100s with "
338 "correct key but not from a permitted "
339 "host (host=%.200s, ip=%.200s).",
340 pw->pw_name, remote_host, remote_ip);
341 logged_from_hostip = 1;
342 }
343 auth_debug_add("Your host '%.200s' is not "
344 "permitted to use this key for login.",
345 remote_host);
346 break;
347 }
348 /* deny access */
349 return 0;
350 }
351 cp = "permitopen=\"";
352 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
353 char *host, *p;
354 int port;
355 char *patterns = xmalloc(strlen(opts) + 1);
356
357 opts += strlen(cp);
358 i = 0;
359 while (*opts) {
360 if (*opts == '"')
361 break;
362 if (*opts == '\\' && opts[1] == '"') {
363 opts += 2;
364 patterns[i++] = '"';
365 continue;
366 }
367 patterns[i++] = *opts++;
368 }
369 if (!*opts) {
370 debug("%.100s, line %lu: missing end quote",
371 file, linenum);
372 auth_debug_add("%.100s, line %lu: missing "
373 "end quote", file, linenum);
374 free(patterns);
375 goto bad_option;
376 }
377 patterns[i] = '\0';
378 opts++;
379 p = patterns;
380 /* XXX - add streamlocal support */
381 host = hpdelim(&p);
382 if (host == NULL || strlen(host) >= NI_MAXHOST) {
383 debug("%.100s, line %lu: Bad permitopen "
384 "specification <%.100s>", file, linenum,
385 patterns);
386 auth_debug_add("%.100s, line %lu: "
387 "Bad permitopen specification", file,
388 linenum);
389 free(patterns);
390 goto bad_option;
391 }
392 host = cleanhostname(host);
393 if (p == NULL || (port = permitopen_port(p)) < 0) {
394 debug("%.100s, line %lu: Bad permitopen port "
395 "<%.100s>", file, linenum, p ? p : "");
396 auth_debug_add("%.100s, line %lu: "
397 "Bad permitopen port", file, linenum);
398 free(patterns);
399 goto bad_option;
400 }
401 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0)
402 channel_add_permitted_opens(ssh, host, port);
403 free(patterns);
404 goto next_option;
405 }
406 cp = "tunnel=\"";
407 if (strncasecmp(opts, cp, strlen(cp)) == 0) {
408 char *tun = NULL;
409 opts += strlen(cp);
410 tun = xmalloc(strlen(opts) + 1);
411 i = 0;
412 while (*opts) {
413 if (*opts == '"')
414 break;
415 tun[i++] = *opts++;
416 }
417 if (!*opts) {
418 debug("%.100s, line %lu: missing end quote",
419 file, linenum);
420 auth_debug_add("%.100s, line %lu: missing end quote",
421 file, linenum);
422 free(tun);
423 forced_tun_device = -1;
424 goto bad_option;
425 }
426 tun[i] = '\0';
427 forced_tun_device = a2tun(tun, NULL);
428 free(tun);
429 if (forced_tun_device == SSH_TUNID_ERR) {
430 debug("%.100s, line %lu: invalid tun device",
431 file, linenum);
432 auth_debug_add("%.100s, line %lu: invalid tun device",
433 file, linenum);
434 forced_tun_device = -1;
435 goto bad_option;
436 }
437 auth_debug_add("Forced tun device: %d", forced_tun_device);
438 opts++;
439 goto next_option;
440 }
441next_option:
442 /*
443 * Skip the comma, and move to the next option
444 * (or break out if there are no more).
445 */
446 if (!*opts)
447 fatal("Bugs in auth-options.c option processing.");
448 if (*opts == ' ' || *opts == '\t')
449 break; /* End of options. */
450 if (*opts != ',')
451 goto bad_option;
452 opts++;
453 /* Process the next option. */
454 } 107 }
108 return 0;
109}
455 110
456 /* grant access */ 111static int
457 return 1; 112dup_strings(char ***dstp, size_t *ndstp, char **src, size_t nsrc)
113{
114 char **dst;
115 size_t i, j;
458 116
459bad_option: 117 *dstp = NULL;
460 logit("Bad options in %.100s file, line %lu: %.50s", 118 *ndstp = 0;
461 file, linenum, opts); 119 if (nsrc == 0)
462 auth_debug_add("Bad options in %.100s file, line %lu: %.50s", 120 return 0;
463 file, linenum, opts);
464 121
465 /* deny access */ 122 if ((dst = calloc(nsrc, sizeof(*src))) == NULL)
123 return -1;
124 for (i = 0; i < nsrc; i++) {
125 if ((dst[i] = strdup(src[i])) == NULL) {
126 for (j = 0; j < i; j++)
127 free(dst[j]);
128 free(dst);
129 return -1;
130 }
131 }
132 /* success */
133 *dstp = dst;
134 *ndstp = nsrc;
466 return 0; 135 return 0;
467} 136}
468 137
469#define OPTIONS_CRITICAL 1 138#define OPTIONS_CRITICAL 1
470#define OPTIONS_EXTENSIONS 2 139#define OPTIONS_EXTENSIONS 2
471static int 140static int
472parse_option_list(struct sshbuf *oblob, struct passwd *pw, 141cert_option_list(struct sshauthopt *opts, struct sshbuf *oblob,
473 u_int which, int crit, 142 u_int which, int crit)
474 int *cert_no_port_forwarding_flag,
475 int *cert_no_agent_forwarding_flag,
476 int *cert_no_x11_forwarding_flag,
477 int *cert_no_pty_flag,
478 int *cert_no_user_rc,
479 char **cert_forced_command,
480 int *cert_source_address_done)
481{ 143{
482 struct ssh *ssh = active_state; /* XXX */
483 char *command, *allowed; 144 char *command, *allowed;
484 const char *remote_ip;
485 char *name = NULL; 145 char *name = NULL;
486 struct sshbuf *c = NULL, *data = NULL; 146 struct sshbuf *c = NULL, *data = NULL;
487 int r, ret = -1, result, found; 147 int r, ret = -1, found;
488 148
489 if ((c = sshbuf_fromb(oblob)) == NULL) { 149 if ((c = sshbuf_fromb(oblob)) == NULL) {
490 error("%s: sshbuf_fromb failed", __func__); 150 error("%s: sshbuf_fromb failed", __func__);
@@ -505,21 +165,21 @@ parse_option_list(struct sshbuf *oblob, struct passwd *pw,
505 found = 0; 165 found = 0;
506 if ((which & OPTIONS_EXTENSIONS) != 0) { 166 if ((which & OPTIONS_EXTENSIONS) != 0) {
507 if (strcmp(name, "permit-X11-forwarding") == 0) { 167 if (strcmp(name, "permit-X11-forwarding") == 0) {
508 *cert_no_x11_forwarding_flag = 0; 168 opts->permit_x11_forwarding_flag = 1;
509 found = 1; 169 found = 1;
510 } else if (strcmp(name, 170 } else if (strcmp(name,
511 "permit-agent-forwarding") == 0) { 171 "permit-agent-forwarding") == 0) {
512 *cert_no_agent_forwarding_flag = 0; 172 opts->permit_agent_forwarding_flag = 1;
513 found = 1; 173 found = 1;
514 } else if (strcmp(name, 174 } else if (strcmp(name,
515 "permit-port-forwarding") == 0) { 175 "permit-port-forwarding") == 0) {
516 *cert_no_port_forwarding_flag = 0; 176 opts->permit_port_forwarding_flag = 1;
517 found = 1; 177 found = 1;
518 } else if (strcmp(name, "permit-pty") == 0) { 178 } else if (strcmp(name, "permit-pty") == 0) {
519 *cert_no_pty_flag = 0; 179 opts->permit_pty_flag = 1;
520 found = 1; 180 found = 1;
521 } else if (strcmp(name, "permit-user-rc") == 0) { 181 } else if (strcmp(name, "permit-user-rc") == 0) {
522 *cert_no_user_rc = 0; 182 opts->permit_user_rc = 1;
523 found = 1; 183 found = 1;
524 } 184 }
525 } 185 }
@@ -531,13 +191,13 @@ parse_option_list(struct sshbuf *oblob, struct passwd *pw,
531 "section: %s", name, ssh_err(r)); 191 "section: %s", name, ssh_err(r));
532 goto out; 192 goto out;
533 } 193 }
534 if (*cert_forced_command != NULL) { 194 if (opts->force_command != NULL) {
535 error("Certificate has multiple " 195 error("Certificate has multiple "
536 "force-command options"); 196 "force-command options");
537 free(command); 197 free(command);
538 goto out; 198 goto out;
539 } 199 }
540 *cert_forced_command = command; 200 opts->force_command = command;
541 found = 1; 201 found = 1;
542 } 202 }
543 if (strcmp(name, "source-address") == 0) { 203 if (strcmp(name, "source-address") == 0) {
@@ -547,41 +207,19 @@ parse_option_list(struct sshbuf *oblob, struct passwd *pw,
547 "section: %s", name, ssh_err(r)); 207 "section: %s", name, ssh_err(r));
548 goto out; 208 goto out;
549 } 209 }
550 if ((*cert_source_address_done)++) { 210 if (opts->required_from_host_cert != NULL) {
551 error("Certificate has multiple " 211 error("Certificate has multiple "
552 "source-address options"); 212 "source-address options");
553 free(allowed); 213 free(allowed);
554 goto out; 214 goto out;
555 } 215 }
556 remote_ip = ssh_remote_ipaddr(ssh); 216 /* Check syntax */
557 result = addr_match_cidr_list(remote_ip, 217 if (addr_match_cidr_list(NULL, allowed) == -1) {
558 allowed);
559 free(allowed);
560 switch (result) {
561 case 1:
562 /* accepted */
563 break;
564 case 0:
565 /* no match */
566 if (!logged_cert_hostip) {
567 logit("Authentication tried for %.100s "
568 "with valid certificate but not "
569 "from a permitted host "
570 "(ip=%.200s).", pw->pw_name,
571 remote_ip);
572 logged_cert_hostip = 1;
573 }
574 auth_debug_add("Your address '%.200s' "
575 "is not permitted to use this "
576 "certificate for login.",
577 remote_ip);
578 goto out;
579 case -1:
580 default:
581 error("Certificate source-address " 218 error("Certificate source-address "
582 "contents invalid"); 219 "contents invalid");
583 goto out; 220 goto out;
584 } 221 }
222 opts->required_from_host_cert = allowed;
585 found = 1; 223 found = 1;
586 } 224 }
587 } 225 }
@@ -607,74 +245,628 @@ parse_option_list(struct sshbuf *oblob, struct passwd *pw,
607 ret = 0; 245 ret = 0;
608 246
609 out: 247 out:
610 if (ret != 0 &&
611 cert_forced_command != NULL &&
612 *cert_forced_command != NULL) {
613 free(*cert_forced_command);
614 *cert_forced_command = NULL;
615 }
616 free(name); 248 free(name);
617 sshbuf_free(data); 249 sshbuf_free(data);
618 sshbuf_free(c); 250 sshbuf_free(c);
619 return ret; 251 return ret;
620} 252}
621 253
254struct sshauthopt *
255sshauthopt_new(void)
256{
257 struct sshauthopt *ret;
258
259 if ((ret = calloc(1, sizeof(*ret))) == NULL)
260 return NULL;
261 ret->force_tun_device = -1;
262 return ret;
263}
264
265void
266sshauthopt_free(struct sshauthopt *opts)
267{
268 size_t i;
269
270 if (opts == NULL)
271 return;
272
273 free(opts->cert_principals);
274 free(opts->force_command);
275 free(opts->required_from_host_cert);
276 free(opts->required_from_host_keys);
277
278 for (i = 0; i < opts->nenv; i++)
279 free(opts->env[i]);
280 free(opts->env);
281
282 for (i = 0; i < opts->npermitopen; i++)
283 free(opts->permitopen[i]);
284 free(opts->permitopen);
285
286 explicit_bzero(opts, sizeof(*opts));
287 free(opts);
288}
289
290struct sshauthopt *
291sshauthopt_new_with_keys_defaults(void)
292{
293 struct sshauthopt *ret = NULL;
294
295 if ((ret = sshauthopt_new()) == NULL)
296 return NULL;
297
298 /* Defaults for authorized_keys flags */
299 ret->permit_port_forwarding_flag = 1;
300 ret->permit_agent_forwarding_flag = 1;
301 ret->permit_x11_forwarding_flag = 1;
302 ret->permit_pty_flag = 1;
303 ret->permit_user_rc = 1;
304 return ret;
305}
306
307struct sshauthopt *
308sshauthopt_parse(const char *opts, const char **errstrp)
309{
310 char **oarray, *opt, *cp, *tmp, *host;
311 int r;
312 struct sshauthopt *ret = NULL;
313 const char *errstr = "unknown error";
314 uint64_t valid_before;
315
316 if (errstrp != NULL)
317 *errstrp = NULL;
318 if ((ret = sshauthopt_new_with_keys_defaults()) == NULL)
319 goto alloc_fail;
320
321 if (opts == NULL)
322 return ret;
323
324 while (*opts && *opts != ' ' && *opts != '\t') {
325 /* flag options */
326 if ((r = opt_flag("restrict", 0, &opts)) != -1) {
327 ret->restricted = 1;
328 ret->permit_port_forwarding_flag = 0;
329 ret->permit_agent_forwarding_flag = 0;
330 ret->permit_x11_forwarding_flag = 0;
331 ret->permit_pty_flag = 0;
332 ret->permit_user_rc = 0;
333 } else if ((r = opt_flag("cert-authority", 0, &opts)) != -1) {
334 ret->cert_authority = r;
335 } else if ((r = opt_flag("port-forwarding", 1, &opts)) != -1) {
336 ret->permit_port_forwarding_flag = r == 1;
337 } else if ((r = opt_flag("agent-forwarding", 1, &opts)) != -1) {
338 ret->permit_agent_forwarding_flag = r == 1;
339 } else if ((r = opt_flag("x11-forwarding", 1, &opts)) != -1) {
340 ret->permit_x11_forwarding_flag = r == 1;
341 } else if ((r = opt_flag("pty", 1, &opts)) != -1) {
342 ret->permit_pty_flag = r == 1;
343 } else if ((r = opt_flag("user-rc", 1, &opts)) != -1) {
344 ret->permit_user_rc = r == 1;
345 } else if (opt_match(&opts, "command")) {
346 if (ret->force_command != NULL) {
347 errstr = "multiple \"command\" clauses";
348 goto fail;
349 }
350 ret->force_command = opt_dequote(&opts, &errstr);
351 if (ret->force_command == NULL)
352 goto fail;
353 } else if (opt_match(&opts, "principals")) {
354 if (ret->cert_principals != NULL) {
355 errstr = "multiple \"principals\" clauses";
356 goto fail;
357 }
358 ret->cert_principals = opt_dequote(&opts, &errstr);
359 if (ret->cert_principals == NULL)
360 goto fail;
361 } else if (opt_match(&opts, "from")) {
362 if (ret->required_from_host_keys != NULL) {
363 errstr = "multiple \"from\" clauses";
364 goto fail;
365 }
366 ret->required_from_host_keys = opt_dequote(&opts,
367 &errstr);
368 if (ret->required_from_host_keys == NULL)
369 goto fail;
370 } else if (opt_match(&opts, "expiry-time")) {
371 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
372 goto fail;
373 if (parse_absolute_time(opt, &valid_before) != 0 ||
374 valid_before == 0) {
375 free(opt);
376 errstr = "invalid expires time";
377 goto fail;
378 }
379 free(opt);
380 if (ret->valid_before == 0 ||
381 valid_before < ret->valid_before)
382 ret->valid_before = valid_before;
383 } else if (opt_match(&opts, "environment")) {
384 if (ret->nenv > INT_MAX) {
385 errstr = "too many environment strings";
386 goto fail;
387 }
388 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
389 goto fail;
390 /* env name must be alphanumeric and followed by '=' */
391 if ((tmp = strchr(opt, '=')) == NULL) {
392 free(opt);
393 errstr = "invalid environment string";
394 goto fail;
395 }
396 for (cp = opt; cp < tmp; cp++) {
397 if (!isalnum((u_char)*cp)) {
398 free(opt);
399 errstr = "invalid environment string";
400 goto fail;
401 }
402 }
403 /* Append it. */
404 oarray = ret->env;
405 if ((ret->env = recallocarray(ret->env, ret->nenv,
406 ret->nenv + 1, sizeof(*ret->env))) == NULL) {
407 free(opt);
408 ret->env = oarray; /* put it back for cleanup */
409 goto alloc_fail;
410 }
411 ret->env[ret->nenv++] = opt;
412 } else if (opt_match(&opts, "permitopen")) {
413 if (ret->npermitopen > INT_MAX) {
414 errstr = "too many permitopens";
415 goto fail;
416 }
417 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
418 goto fail;
419 if ((tmp = strdup(opt)) == NULL) {
420 free(opt);
421 goto alloc_fail;
422 }
423 cp = tmp;
424 /* validate syntax of permitopen before recording it. */
425 host = hpdelim(&cp);
426 if (host == NULL || strlen(host) >= NI_MAXHOST) {
427 free(tmp);
428 free(opt);
429 errstr = "invalid permitopen hostname";
430 goto fail;
431 }
432 /*
433 * don't want to use permitopen_port to avoid
434 * dependency on channels.[ch] here.
435 */
436 if (cp == NULL ||
437 (strcmp(cp, "*") != 0 && a2port(cp) <= 0)) {
438 free(tmp);
439 free(opt);
440 errstr = "invalid permitopen port";
441 goto fail;
442 }
443 /* XXX - add streamlocal support */
444 free(tmp);
445 /* Record it */
446 oarray = ret->permitopen;
447 if ((ret->permitopen = recallocarray(ret->permitopen,
448 ret->npermitopen, ret->npermitopen + 1,
449 sizeof(*ret->permitopen))) == NULL) {
450 free(opt);
451 ret->permitopen = oarray;
452 goto alloc_fail;
453 }
454 ret->permitopen[ret->npermitopen++] = opt;
455 } else if (opt_match(&opts, "tunnel")) {
456 if ((opt = opt_dequote(&opts, &errstr)) == NULL)
457 goto fail;
458 ret->force_tun_device = a2tun(opt, NULL);
459 free(opt);
460 if (ret->force_tun_device == SSH_TUNID_ERR) {
461 errstr = "invalid tun device";
462 goto fail;
463 }
464 }
465 /*
466 * Skip the comma, and move to the next option
467 * (or break out if there are no more).
468 */
469 if (*opts == '\0' || *opts == ' ' || *opts == '\t')
470 break; /* End of options. */
471 /* Anything other than a comma is an unknown option */
472 if (*opts != ',') {
473 errstr = "unknown key option";
474 goto fail;
475 }
476 opts++;
477 if (*opts == '\0') {
478 errstr = "unexpected end-of-options";
479 goto fail;
480 }
481 }
482
483 /* success */
484 if (errstrp != NULL)
485 *errstrp = NULL;
486 return ret;
487
488alloc_fail:
489 errstr = "memory allocation failed";
490fail:
491 sshauthopt_free(ret);
492 if (errstrp != NULL)
493 *errstrp = errstr;
494 return NULL;
495}
496
497struct sshauthopt *
498sshauthopt_from_cert(struct sshkey *k)
499{
500 struct sshauthopt *ret;
501
502 if (k == NULL || !sshkey_type_is_cert(k->type) || k->cert == NULL ||
503 k->cert->type != SSH2_CERT_TYPE_USER)
504 return NULL;
505
506 if ((ret = sshauthopt_new()) == NULL)
507 return NULL;
508
509 /* Handle options and critical extensions separately */
510 if (cert_option_list(ret, k->cert->critical,
511 OPTIONS_CRITICAL, 1) == -1) {
512 sshauthopt_free(ret);
513 return NULL;
514 }
515 if (cert_option_list(ret, k->cert->extensions,
516 OPTIONS_EXTENSIONS, 0) == -1) {
517 sshauthopt_free(ret);
518 return NULL;
519 }
520 /* success */
521 return ret;
522}
523
622/* 524/*
623 * Set options from critical certificate options. These supersede user key 525 * Merges "additional" options to "primary" and returns the result.
624 * options so this must be called after auth_parse_options(). 526 * NB. Some options from primary have primacy.
625 */ 527 */
626int 528struct sshauthopt *
627auth_cert_options(struct sshkey *k, struct passwd *pw, const char **reason) 529sshauthopt_merge(const struct sshauthopt *primary,
530 const struct sshauthopt *additional, const char **errstrp)
628{ 531{
629 int cert_no_port_forwarding_flag = 1; 532 struct sshauthopt *ret;
630 int cert_no_agent_forwarding_flag = 1; 533 const char *errstr = "internal error";
631 int cert_no_x11_forwarding_flag = 1; 534 const char *tmp;
632 int cert_no_pty_flag = 1; 535
633 int cert_no_user_rc = 1; 536 if (errstrp != NULL)
634 char *cert_forced_command = NULL; 537 *errstrp = NULL;
635 int cert_source_address_done = 0; 538
636 539 if ((ret = sshauthopt_new()) == NULL)
637 *reason = "invalid certificate options"; 540 goto alloc_fail;
638 541
639 /* Separate options and extensions for v01 certs */ 542 /* cert_authority and cert_principals are cleared in result */
640 if (parse_option_list(k->cert->critical, pw, 543
641 OPTIONS_CRITICAL, 1, NULL, NULL, NULL, NULL, NULL, 544 /* Prefer access lists from primary. */
642 &cert_forced_command, 545 /* XXX err is both set and mismatch? */
643 &cert_source_address_done) == -1) 546 tmp = primary->required_from_host_cert;
644 return -1; 547 if (tmp == NULL)
645 if (parse_option_list(k->cert->extensions, pw, 548 tmp = additional->required_from_host_cert;
646 OPTIONS_EXTENSIONS, 0, 549 if (tmp != NULL && (ret->required_from_host_cert = strdup(tmp)) == NULL)
647 &cert_no_port_forwarding_flag, 550 goto alloc_fail;
648 &cert_no_agent_forwarding_flag, 551 tmp = primary->required_from_host_keys;
649 &cert_no_x11_forwarding_flag, 552 if (tmp == NULL)
650 &cert_no_pty_flag, 553 tmp = additional->required_from_host_keys;
651 &cert_no_user_rc, 554 if (tmp != NULL && (ret->required_from_host_keys = strdup(tmp)) == NULL)
652 NULL, NULL) == -1) 555 goto alloc_fail;
653 return -1; 556
557 /* force_tun_device, permitopen and environment prefer the primary. */
558 ret->force_tun_device = primary->force_tun_device;
559 if (ret->force_tun_device == -1)
560 ret->force_tun_device = additional->force_tun_device;
561 if (primary->nenv > 0) {
562 if (dup_strings(&ret->env, &ret->nenv,
563 primary->env, primary->nenv) != 0)
564 goto alloc_fail;
565 } else if (additional->nenv) {
566 if (dup_strings(&ret->env, &ret->nenv,
567 additional->env, additional->nenv) != 0)
568 goto alloc_fail;
569 }
570 if (primary->npermitopen > 0) {
571 if (dup_strings(&ret->permitopen, &ret->npermitopen,
572 primary->permitopen, primary->npermitopen) != 0)
573 goto alloc_fail;
574 } else if (additional->npermitopen > 0) {
575 if (dup_strings(&ret->permitopen, &ret->npermitopen,
576 additional->permitopen, additional->npermitopen) != 0)
577 goto alloc_fail;
578 }
579
580 /* Flags are logical-AND (i.e. must be set in both for permission) */
581#define OPTFLAG(x) ret->x = (primary->x == 1) && (additional->x == 1)
582 OPTFLAG(permit_port_forwarding_flag);
583 OPTFLAG(permit_agent_forwarding_flag);
584 OPTFLAG(permit_x11_forwarding_flag);
585 OPTFLAG(permit_pty_flag);
586 OPTFLAG(permit_user_rc);
587#undef OPTFLAG
588
589 /* Earliest expiry time should win */
590 if (primary->valid_before != 0)
591 ret->valid_before = primary->valid_before;
592 if (additional->valid_before != 0 &&
593 additional->valid_before < ret->valid_before)
594 ret->valid_before = additional->valid_before;
654 595
655 no_port_forwarding_flag |= cert_no_port_forwarding_flag;
656 no_agent_forwarding_flag |= cert_no_agent_forwarding_flag;
657 no_x11_forwarding_flag |= cert_no_x11_forwarding_flag;
658 no_pty_flag |= cert_no_pty_flag;
659 no_user_rc |= cert_no_user_rc;
660 /* 596 /*
661 * Only permit both CA and key option forced-command if they match. 597 * When both multiple forced-command are specified, only
662 * Otherwise refuse the certificate. 598 * proceed if they are identical, otherwise fail.
663 */ 599 */
664 if (cert_forced_command != NULL && forced_command != NULL) { 600 if (primary->force_command != NULL &&
665 if (strcmp(forced_command, cert_forced_command) == 0) { 601 additional->force_command != NULL) {
666 free(forced_command); 602 if (strcmp(primary->force_command,
667 forced_command = cert_forced_command; 603 additional->force_command) == 0) {
604 /* ok */
605 ret->force_command = strdup(primary->force_command);
606 if (ret->force_command == NULL)
607 goto alloc_fail;
668 } else { 608 } else {
669 *reason = "certificate and key options forced command " 609 errstr = "forced command options do not match";
670 "do not match"; 610 goto fail;
671 free(cert_forced_command); 611 }
672 return -1; 612 } else if (primary->force_command != NULL) {
613 if ((ret->force_command = strdup(
614 primary->force_command)) == NULL)
615 goto alloc_fail;
616 } else if (additional->force_command != NULL) {
617 if ((ret->force_command = strdup(
618 additional->force_command)) == NULL)
619 goto alloc_fail;
620 }
621 /* success */
622 if (errstrp != NULL)
623 *errstrp = NULL;
624 return ret;
625
626 alloc_fail:
627 errstr = "memory allocation failed";
628 fail:
629 if (errstrp != NULL)
630 *errstrp = errstr;
631 sshauthopt_free(ret);
632 return NULL;
633}
634
635/*
636 * Copy options
637 */
638struct sshauthopt *
639sshauthopt_copy(const struct sshauthopt *orig)
640{
641 struct sshauthopt *ret;
642
643 if ((ret = sshauthopt_new()) == NULL)
644 return NULL;
645
646#define OPTSCALAR(x) ret->x = orig->x
647 OPTSCALAR(permit_port_forwarding_flag);
648 OPTSCALAR(permit_agent_forwarding_flag);
649 OPTSCALAR(permit_x11_forwarding_flag);
650 OPTSCALAR(permit_pty_flag);
651 OPTSCALAR(permit_user_rc);
652 OPTSCALAR(restricted);
653 OPTSCALAR(cert_authority);
654 OPTSCALAR(force_tun_device);
655 OPTSCALAR(valid_before);
656#undef OPTSCALAR
657#define OPTSTRING(x) \
658 do { \
659 if (orig->x != NULL && (ret->x = strdup(orig->x)) == NULL) { \
660 sshauthopt_free(ret); \
661 return NULL; \
662 } \
663 } while (0)
664 OPTSTRING(cert_principals);
665 OPTSTRING(force_command);
666 OPTSTRING(required_from_host_cert);
667 OPTSTRING(required_from_host_keys);
668#undef OPTSTRING
669
670 if (dup_strings(&ret->env, &ret->nenv, orig->env, orig->nenv) != 0 ||
671 dup_strings(&ret->permitopen, &ret->npermitopen,
672 orig->permitopen, orig->npermitopen) != 0) {
673 sshauthopt_free(ret);
674 return NULL;
675 }
676 return ret;
677}
678
679static int
680serialise_array(struct sshbuf *m, char **a, size_t n)
681{
682 struct sshbuf *b;
683 size_t i;
684 int r;
685
686 if (n > INT_MAX)
687 return SSH_ERR_INTERNAL_ERROR;
688
689 if ((b = sshbuf_new()) == NULL) {
690 return SSH_ERR_ALLOC_FAIL;
691 }
692 for (i = 0; i < n; i++) {
693 if ((r = sshbuf_put_cstring(b, a[i])) != 0) {
694 sshbuf_free(b);
695 return r;
673 } 696 }
674 } else if (cert_forced_command != NULL) 697 }
675 forced_command = cert_forced_command; 698 if ((r = sshbuf_put_u32(m, n)) != 0 ||
699 (r = sshbuf_put_stringb(m, b)) != 0) {
700 sshbuf_free(b);
701 return r;
702 }
676 /* success */ 703 /* success */
677 *reason = NULL;
678 return 0; 704 return 0;
679} 705}
680 706
707static int
708deserialise_array(struct sshbuf *m, char ***ap, size_t *np)
709{
710 char **a = NULL;
711 size_t i, n = 0;
712 struct sshbuf *b = NULL;
713 u_int tmp;
714 int r = SSH_ERR_INTERNAL_ERROR;
715
716 if ((r = sshbuf_get_u32(m, &tmp)) != 0 ||
717 (r = sshbuf_froms(m, &b)) != 0)
718 goto out;
719 if (tmp > INT_MAX) {
720 r = SSH_ERR_INVALID_FORMAT;
721 goto out;
722 }
723 n = tmp;
724 if (n > 0 && (a = calloc(n, sizeof(*a))) == NULL) {
725 r = SSH_ERR_ALLOC_FAIL;
726 goto out;
727 }
728 for (i = 0; i < n; i++) {
729 if ((r = sshbuf_get_cstring(b, &a[i], NULL)) != 0)
730 goto out;
731 }
732 /* success */
733 r = 0;
734 *ap = a;
735 a = NULL;
736 *np = n;
737 n = 0;
738 out:
739 for (i = 0; i < n; i++)
740 free(a[i]);
741 free(a);
742 sshbuf_free(b);
743 return r;
744}
745
746static int
747serialise_nullable_string(struct sshbuf *m, const char *s)
748{
749 int r;
750
751 if ((r = sshbuf_put_u8(m, s == NULL)) != 0 ||
752 (r = sshbuf_put_cstring(m, s)) != 0)
753 return r;
754 return 0;
755}
756
757static int
758deserialise_nullable_string(struct sshbuf *m, char **sp)
759{
760 int r;
761 u_char flag;
762
763 *sp = NULL;
764 if ((r = sshbuf_get_u8(m, &flag)) != 0 ||
765 (r = sshbuf_get_cstring(m, flag ? NULL : sp, NULL)) != 0)
766 return r;
767 return 0;
768}
769
770int
771sshauthopt_serialise(const struct sshauthopt *opts, struct sshbuf *m,
772 int untrusted)
773{
774 int r = SSH_ERR_INTERNAL_ERROR;
775
776 /* Flag and simple integer options */
777 if ((r = sshbuf_put_u8(m, opts->permit_port_forwarding_flag)) != 0 ||
778 (r = sshbuf_put_u8(m, opts->permit_agent_forwarding_flag)) != 0 ||
779 (r = sshbuf_put_u8(m, opts->permit_x11_forwarding_flag)) != 0 ||
780 (r = sshbuf_put_u8(m, opts->permit_pty_flag)) != 0 ||
781 (r = sshbuf_put_u8(m, opts->permit_user_rc)) != 0 ||
782 (r = sshbuf_put_u8(m, opts->restricted)) != 0 ||
783 (r = sshbuf_put_u8(m, opts->cert_authority)) != 0 ||
784 (r = sshbuf_put_u64(m, opts->valid_before)) != 0)
785 return r;
786
787 /* tunnel number can be negative to indicate "unset" */
788 if ((r = sshbuf_put_u8(m, opts->force_tun_device == -1)) != 0 ||
789 (r = sshbuf_put_u32(m, (opts->force_tun_device < 0) ?
790 0 : (u_int)opts->force_tun_device)) != 0)
791 return r;
792
793 /* String options; these may be NULL */
794 if ((r = serialise_nullable_string(m,
795 untrusted ? "yes" : opts->cert_principals)) != 0 ||
796 (r = serialise_nullable_string(m,
797 untrusted ? "true" : opts->force_command)) != 0 ||
798 (r = serialise_nullable_string(m,
799 untrusted ? NULL : opts->required_from_host_cert)) != 0 ||
800 (r = serialise_nullable_string(m,
801 untrusted ? NULL : opts->required_from_host_keys)) != 0)
802 return r;
803
804 /* Array options */
805 if ((r = serialise_array(m, opts->env,
806 untrusted ? 0 : opts->nenv)) != 0 ||
807 (r = serialise_array(m, opts->permitopen,
808 untrusted ? 0 : opts->npermitopen)) != 0)
809 return r;
810
811 /* success */
812 return 0;
813}
814
815int
816sshauthopt_deserialise(struct sshbuf *m, struct sshauthopt **optsp)
817{
818 struct sshauthopt *opts = NULL;
819 int r = SSH_ERR_INTERNAL_ERROR;
820 u_char f;
821 u_int tmp;
822
823 if ((opts = calloc(1, sizeof(*opts))) == NULL)
824 return SSH_ERR_ALLOC_FAIL;
825
826#define OPT_FLAG(x) \
827 do { \
828 if ((r = sshbuf_get_u8(m, &f)) != 0) \
829 goto out; \
830 opts->x = f; \
831 } while (0)
832 OPT_FLAG(permit_port_forwarding_flag);
833 OPT_FLAG(permit_agent_forwarding_flag);
834 OPT_FLAG(permit_x11_forwarding_flag);
835 OPT_FLAG(permit_pty_flag);
836 OPT_FLAG(permit_user_rc);
837 OPT_FLAG(restricted);
838 OPT_FLAG(cert_authority);
839#undef OPT_FLAG
840
841 if ((r = sshbuf_get_u64(m, &opts->valid_before)) != 0)
842 goto out;
843
844 /* tunnel number can be negative to indicate "unset" */
845 if ((r = sshbuf_get_u8(m, &f)) != 0 ||
846 (r = sshbuf_get_u32(m, &tmp)) != 0)
847 goto out;
848 opts->force_tun_device = f ? -1 : (int)tmp;
849
850 /* String options may be NULL */
851 if ((r = deserialise_nullable_string(m, &opts->cert_principals)) != 0 ||
852 (r = deserialise_nullable_string(m, &opts->force_command)) != 0 ||
853 (r = deserialise_nullable_string(m,
854 &opts->required_from_host_cert)) != 0 ||
855 (r = deserialise_nullable_string(m,
856 &opts->required_from_host_keys)) != 0)
857 goto out;
858
859 /* Array options */
860 if ((r = deserialise_array(m, &opts->env, &opts->nenv)) != 0 ||
861 (r = deserialise_array(m,
862 &opts->permitopen, &opts->npermitopen)) != 0)
863 goto out;
864
865 /* success */
866 r = 0;
867 *optsp = opts;
868 opts = NULL;
869 out:
870 sshauthopt_free(opts);
871 return r;
872}
generated by cgit v1.2.3 (git 2.39.1) at 2024-09-30 14:29:36 +0000