1 /* $OpenBSD: auth-options.c,v 1.64 2014/07/15 15:54:14 millert Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
15 #include <sys/types.h>
23 #include "openbsd-compat/sys-queue.h"
33 #include "auth-options.h"
37 /* Flags set authorized_keys flags */
38 int no_port_forwarding_flag
= 0;
39 int no_agent_forwarding_flag
= 0;
40 int no_x11_forwarding_flag
= 0;
43 int key_is_cert_authority
= 0;
45 /* "command=" option. */
46 char *forced_command
= NULL
;
48 /* "environment=" options. */
49 struct envstring
*custom_environment
= NULL
;
51 /* "tunnel=" option. */
52 int forced_tun_device
= -1;
54 /* "principals=" option. */
55 char *authorized_principals
= NULL
;
57 extern ServerOptions options
;
60 auth_clear_options(void)
62 no_agent_forwarding_flag
= 0;
63 no_port_forwarding_flag
= 0;
65 no_x11_forwarding_flag
= 0;
67 key_is_cert_authority
= 0;
68 while (custom_environment
) {
69 struct envstring
*ce
= custom_environment
;
70 custom_environment
= ce
->next
;
76 forced_command
= NULL
;
78 if (authorized_principals
) {
79 free(authorized_principals
);
80 authorized_principals
= NULL
;
82 forced_tun_device
= -1;
83 channel_clear_permitted_opens();
87 * return 1 if access is granted, 0 if not.
88 * side effect: sets key option flags
91 auth_parse_options(struct passwd
*pw
, char *opts
, char *file
, u_long linenum
)
102 while (*opts
&& *opts
!= ' ' && *opts
!= '\t') {
103 cp
= "cert-authority";
104 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
105 key_is_cert_authority
= 1;
109 cp
= "no-port-forwarding";
110 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
111 auth_debug_add("Port forwarding disabled.");
112 no_port_forwarding_flag
= 1;
116 cp
= "no-agent-forwarding";
117 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
118 auth_debug_add("Agent forwarding disabled.");
119 no_agent_forwarding_flag
= 1;
123 cp
= "no-X11-forwarding";
124 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
125 auth_debug_add("X11 forwarding disabled.");
126 no_x11_forwarding_flag
= 1;
131 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
132 auth_debug_add("Pty allocation disabled.");
138 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
139 auth_debug_add("User rc file execution disabled.");
145 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
147 if (forced_command
!= NULL
)
148 free(forced_command
);
149 forced_command
= xmalloc(strlen(opts
) + 1);
154 if (*opts
== '\\' && opts
[1] == '"') {
156 forced_command
[i
++] = '"';
159 forced_command
[i
++] = *opts
++;
162 debug("%.100s, line %lu: missing end quote",
164 auth_debug_add("%.100s, line %lu: missing end quote",
166 free(forced_command
);
167 forced_command
= NULL
;
170 forced_command
[i
] = '\0';
171 auth_debug_add("Forced command.");
175 cp
= "principals=\"";
176 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
178 if (authorized_principals
!= NULL
)
179 free(authorized_principals
);
180 authorized_principals
= xmalloc(strlen(opts
) + 1);
185 if (*opts
== '\\' && opts
[1] == '"') {
187 authorized_principals
[i
++] = '"';
190 authorized_principals
[i
++] = *opts
++;
193 debug("%.100s, line %lu: missing end quote",
195 auth_debug_add("%.100s, line %lu: missing end quote",
197 free(authorized_principals
);
198 authorized_principals
= NULL
;
201 authorized_principals
[i
] = '\0';
202 auth_debug_add("principals: %.900s",
203 authorized_principals
);
207 cp
= "environment=\"";
208 if (options
.permit_user_env
&&
209 strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
211 struct envstring
*new_envstring
;
214 s
= xmalloc(strlen(opts
) + 1);
219 if (*opts
== '\\' && opts
[1] == '"') {
227 debug("%.100s, line %lu: missing end quote",
229 auth_debug_add("%.100s, line %lu: missing end quote",
235 auth_debug_add("Adding to environment: %.900s", s
);
236 debug("Adding to environment: %.900s", s
);
238 new_envstring
= xcalloc(1, sizeof(struct envstring
));
239 new_envstring
->s
= s
;
240 new_envstring
->next
= custom_environment
;
241 custom_environment
= new_envstring
;
245 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
246 const char *remote_ip
= get_remote_ipaddr();
247 const char *remote_host
= get_canonical_hostname(
249 char *patterns
= xmalloc(strlen(opts
) + 1);
256 if (*opts
== '\\' && opts
[1] == '"') {
261 patterns
[i
++] = *opts
++;
264 debug("%.100s, line %lu: missing end quote",
266 auth_debug_add("%.100s, line %lu: missing end quote",
273 switch (match_host_and_ip(remote_host
, remote_ip
,
277 /* Host name matches. */
280 debug("%.100s, line %lu: invalid criteria",
282 auth_debug_add("%.100s, line %lu: "
283 "invalid criteria", file
, linenum
);
287 logit("Authentication tried for %.100s with "
288 "correct key but not from a permitted "
289 "host (host=%.200s, ip=%.200s).",
290 pw
->pw_name
, remote_host
, remote_ip
);
291 auth_debug_add("Your host '%.200s' is not "
292 "permitted to use this key for login.",
299 cp
= "permitopen=\"";
300 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
303 char *patterns
= xmalloc(strlen(opts
) + 1);
310 if (*opts
== '\\' && opts
[1] == '"') {
315 patterns
[i
++] = *opts
++;
318 debug("%.100s, line %lu: missing end quote",
320 auth_debug_add("%.100s, line %lu: missing "
321 "end quote", file
, linenum
);
328 /* XXX - add streamlocal support */
330 if (host
== NULL
|| strlen(host
) >= NI_MAXHOST
) {
331 debug("%.100s, line %lu: Bad permitopen "
332 "specification <%.100s>", file
, linenum
,
334 auth_debug_add("%.100s, line %lu: "
335 "Bad permitopen specification", file
,
340 host
= cleanhostname(host
);
341 if (p
== NULL
|| (port
= permitopen_port(p
)) < 0) {
342 debug("%.100s, line %lu: Bad permitopen port "
343 "<%.100s>", file
, linenum
, p
? p
: "");
344 auth_debug_add("%.100s, line %lu: "
345 "Bad permitopen port", file
, linenum
);
349 if ((options
.allow_tcp_forwarding
& FORWARD_LOCAL
) != 0)
350 channel_add_permitted_opens(host
, port
);
355 if (strncasecmp(opts
, cp
, strlen(cp
)) == 0) {
358 tun
= xmalloc(strlen(opts
) + 1);
366 debug("%.100s, line %lu: missing end quote",
368 auth_debug_add("%.100s, line %lu: missing end quote",
371 forced_tun_device
= -1;
375 forced_tun_device
= a2tun(tun
, NULL
);
377 if (forced_tun_device
== SSH_TUNID_ERR
) {
378 debug("%.100s, line %lu: invalid tun device",
380 auth_debug_add("%.100s, line %lu: invalid tun device",
382 forced_tun_device
= -1;
385 auth_debug_add("Forced tun device: %d", forced_tun_device
);
391 * Skip the comma, and move to the next option
392 * (or break out if there are no more).
395 fatal("Bugs in auth-options.c option processing.");
396 if (*opts
== ' ' || *opts
== '\t')
397 break; /* End of options. */
401 /* Process the next option. */
408 logit("Bad options in %.100s file, line %lu: %.50s",
409 file
, linenum
, opts
);
410 auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
411 file
, linenum
, opts
);
417 #define OPTIONS_CRITICAL 1
418 #define OPTIONS_EXTENSIONS 2
420 parse_option_list(u_char
*optblob
, size_t optblob_len
, struct passwd
*pw
,
421 u_int which
, int crit
,
422 int *cert_no_port_forwarding_flag
,
423 int *cert_no_agent_forwarding_flag
,
424 int *cert_no_x11_forwarding_flag
,
425 int *cert_no_pty_flag
,
426 int *cert_no_user_rc
,
427 char **cert_forced_command
,
428 int *cert_source_address_done
)
430 char *command
, *allowed
;
431 const char *remote_ip
;
433 u_char
*data_blob
= NULL
;
434 u_int nlen
, dlen
, clen
;
436 int ret
= -1, result
, found
;
440 /* Make copy to avoid altering original */
442 buffer_append(&c
, optblob
, optblob_len
);
444 while (buffer_len(&c
) > 0) {
445 if ((name
= buffer_get_cstring_ret(&c
, &nlen
)) == NULL
||
446 (data_blob
= buffer_get_string_ret(&c
, &dlen
)) == NULL
) {
447 error("Certificate options corrupt");
450 buffer_append(&data
, data_blob
, dlen
);
451 debug3("found certificate option \"%.100s\" len %u",
454 if ((which
& OPTIONS_EXTENSIONS
) != 0) {
455 if (strcmp(name
, "permit-X11-forwarding") == 0) {
456 *cert_no_x11_forwarding_flag
= 0;
458 } else if (strcmp(name
,
459 "permit-agent-forwarding") == 0) {
460 *cert_no_agent_forwarding_flag
= 0;
462 } else if (strcmp(name
,
463 "permit-port-forwarding") == 0) {
464 *cert_no_port_forwarding_flag
= 0;
466 } else if (strcmp(name
, "permit-pty") == 0) {
467 *cert_no_pty_flag
= 0;
469 } else if (strcmp(name
, "permit-user-rc") == 0) {
470 *cert_no_user_rc
= 0;
474 if (!found
&& (which
& OPTIONS_CRITICAL
) != 0) {
475 if (strcmp(name
, "force-command") == 0) {
476 if ((command
= buffer_get_cstring_ret(&data
,
478 error("Certificate constraint \"%s\" "
482 if (*cert_forced_command
!= NULL
) {
483 error("Certificate has multiple "
484 "force-command options");
488 *cert_forced_command
= command
;
491 if (strcmp(name
, "source-address") == 0) {
492 if ((allowed
= buffer_get_cstring_ret(&data
,
494 error("Certificate constraint "
495 "\"%s\" corrupt", name
);
498 if ((*cert_source_address_done
)++) {
499 error("Certificate has multiple "
500 "source-address options");
504 remote_ip
= get_remote_ipaddr();
505 result
= addr_match_cidr_list(remote_ip
,
514 logit("Authentication tried for %.100s "
515 "with valid certificate but not "
516 "from a permitted host "
517 "(ip=%.200s).", pw
->pw_name
,
519 auth_debug_add("Your address '%.200s' "
520 "is not permitted to use this "
521 "certificate for login.",
526 error("Certificate source-address "
536 error("Certificate critical option \"%s\" "
537 "is not supported", name
);
540 logit("Certificate extension \"%s\" "
541 "is not supported", name
);
543 } else if (buffer_len(&data
) != 0) {
544 error("Certificate option \"%s\" corrupt "
545 "(extra data)", name
);
554 /* successfully parsed all options */
559 cert_forced_command
!= NULL
&&
560 *cert_forced_command
!= NULL
) {
561 free(*cert_forced_command
);
562 *cert_forced_command
= NULL
;
566 if (data_blob
!= NULL
)
574 * Set options from critical certificate options. These supersede user key
575 * options so this must be called after auth_parse_options().
578 auth_cert_options(Key
*k
, struct passwd
*pw
)
580 int cert_no_port_forwarding_flag
= 1;
581 int cert_no_agent_forwarding_flag
= 1;
582 int cert_no_x11_forwarding_flag
= 1;
583 int cert_no_pty_flag
= 1;
584 int cert_no_user_rc
= 1;
585 char *cert_forced_command
= NULL
;
586 int cert_source_address_done
= 0;
588 if (key_cert_is_legacy(k
)) {
589 /* All options are in the one field for v00 certs */
590 if (parse_option_list(buffer_ptr(k
->cert
->critical
),
591 buffer_len(k
->cert
->critical
), pw
,
592 OPTIONS_CRITICAL
|OPTIONS_EXTENSIONS
, 1,
593 &cert_no_port_forwarding_flag
,
594 &cert_no_agent_forwarding_flag
,
595 &cert_no_x11_forwarding_flag
,
598 &cert_forced_command
,
599 &cert_source_address_done
) == -1)
602 /* Separate options and extensions for v01 certs */
603 if (parse_option_list(buffer_ptr(k
->cert
->critical
),
604 buffer_len(k
->cert
->critical
), pw
,
605 OPTIONS_CRITICAL
, 1, NULL
, NULL
, NULL
, NULL
, NULL
,
606 &cert_forced_command
,
607 &cert_source_address_done
) == -1)
609 if (parse_option_list(buffer_ptr(k
->cert
->extensions
),
610 buffer_len(k
->cert
->extensions
), pw
,
611 OPTIONS_EXTENSIONS
, 1,
612 &cert_no_port_forwarding_flag
,
613 &cert_no_agent_forwarding_flag
,
614 &cert_no_x11_forwarding_flag
,
621 no_port_forwarding_flag
|= cert_no_port_forwarding_flag
;
622 no_agent_forwarding_flag
|= cert_no_agent_forwarding_flag
;
623 no_x11_forwarding_flag
|= cert_no_x11_forwarding_flag
;
624 no_pty_flag
|= cert_no_pty_flag
;
625 no_user_rc
|= cert_no_user_rc
;
626 /* CA-specified forced command supersedes key option */
627 if (cert_forced_command
!= NULL
) {
628 if (forced_command
!= NULL
)
629 free(forced_command
);
630 forced_command
= cert_forced_command
;