]>
Commit | Line | Data |
---|---|---|
a5c9cd31 | 1 | /* |
09564242 | 2 | * Copyright (c) 2000 Damien Miller. All rights reserved. |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
7 | * 1. Redistributions of source code must retain the above copyright | |
8 | * notice, this list of conditions and the following disclaimer. | |
9 | * 2. Redistributions in binary form must reproduce the above copyright | |
10 | * notice, this list of conditions and the following disclaimer in the | |
11 | * documentation and/or other materials provided with the distribution. | |
09564242 | 12 | * |
13 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
14 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
15 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
16 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
17 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
18 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
19 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
20 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
21 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
22 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
a5c9cd31 | 23 | */ |
24 | ||
25 | #include "includes.h" | |
26 | ||
27 | #ifdef USE_PAM | |
28 | #include "ssh.h" | |
29 | #include "xmalloc.h" | |
42f11eb2 | 30 | #include "log.h" |
5c377b3b | 31 | #include "auth-pam.h" |
a5c9cd31 | 32 | #include "servconf.h" |
42f11eb2 | 33 | #include "canohost.h" |
34 | #include "readpass.h" | |
a5c9cd31 | 35 | |
1ddee76b | 36 | extern char *__progname; |
37 | ||
a5c9cd31 | 38 | RCSID("$Id$"); |
39 | ||
5daf7064 | 40 | #define NEW_AUTHTOK_MSG \ |
ad55cd03 | 41 | "Warning: Your password has expired, please change it now" |
5daf7064 | 42 | |
5c377b3b | 43 | static int do_pam_conversation(int num_msg, const struct pam_message **msg, |
44 | struct pam_response **resp, void *appdata_ptr); | |
a5c9cd31 | 45 | |
46 | /* module-local variables */ | |
47 | static struct pam_conv conv = { | |
5c377b3b | 48 | do_pam_conversation, |
a5c9cd31 | 49 | NULL |
50 | }; | |
e11aab29 | 51 | static char *__pam_msg = NULL; |
52 | static pam_handle_t *__pamh = NULL; | |
53 | static const char *__pampasswd = NULL; | |
a5c9cd31 | 54 | |
5c377b3b | 55 | /* states for do_pam_conversation() */ |
8c9fe09e | 56 | enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN; |
ad55cd03 | 57 | /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_REQD */ |
58 | static int password_change_required = 0; | |
8c9fe09e | 59 | /* remember whether the last pam_authenticate() succeeded or not */ |
60 | static int was_authenticated = 0; | |
61 | ||
e11aab29 | 62 | /* Remember what has been initialised */ |
63 | static int session_opened = 0; | |
64 | static int creds_set = 0; | |
65 | ||
8c9fe09e | 66 | /* accessor which allows us to switch conversation structs according to |
67 | * the authentication method being used */ | |
e11aab29 | 68 | void do_pam_set_conv(struct pam_conv *conv) |
8c9fe09e | 69 | { |
e11aab29 | 70 | pam_set_item(__pamh, PAM_CONV, conv); |
8c9fe09e | 71 | } |
72 | ||
73 | /* start an authentication run */ | |
74 | int do_pam_authenticate(int flags) | |
75 | { | |
e11aab29 | 76 | int retval = pam_authenticate(__pamh, flags); |
8c9fe09e | 77 | was_authenticated = (retval == PAM_SUCCESS); |
78 | return retval; | |
79 | } | |
ad55cd03 | 80 | |
81 | /* | |
82 | * PAM conversation function. | |
83 | * There are two states this can run in. | |
84 | * | |
85 | * INITIAL_LOGIN mode simply feeds the password from the client into | |
86 | * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output | |
e11aab29 | 87 | * messages with into __pam_msg. This is used during initial |
ad55cd03 | 88 | * authentication to bypass the normal PAM password prompt. |
89 | * | |
9678565b | 90 | * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase() |
ad55cd03 | 91 | * and outputs messages to stderr. This mode is used if pam_chauthtok() |
92 | * is called to update expired passwords. | |
93 | */ | |
5c377b3b | 94 | static int do_pam_conversation(int num_msg, const struct pam_message **msg, |
a5c9cd31 | 95 | struct pam_response **resp, void *appdata_ptr) |
96 | { | |
97 | struct pam_response *reply; | |
98 | int count; | |
ad55cd03 | 99 | char buf[1024]; |
a5c9cd31 | 100 | |
101 | /* PAM will free this later */ | |
102 | reply = malloc(num_msg * sizeof(*reply)); | |
103 | if (reply == NULL) | |
2b87da3b | 104 | return PAM_CONV_ERR; |
a5c9cd31 | 105 | |
ad55cd03 | 106 | for (count = 0; count < num_msg; count++) { |
5c377b3b | 107 | if (pamstate == INITIAL_LOGIN) { |
108 | /* | |
109 | * We can't use stdio yet, queue messages for | |
110 | * printing later | |
111 | */ | |
112 | switch(PAM_MSG_MEMBER(msg, count, msg_style)) { | |
ad55cd03 | 113 | case PAM_PROMPT_ECHO_ON: |
5c377b3b | 114 | free(reply); |
115 | return PAM_CONV_ERR; | |
116 | case PAM_PROMPT_ECHO_OFF: | |
e11aab29 | 117 | if (__pampasswd == NULL) { |
71dfaf1c | 118 | free(reply); |
119 | return PAM_CONV_ERR; | |
71dfaf1c | 120 | } |
e11aab29 | 121 | reply[count].resp = xstrdup(__pampasswd); |
a5c9cd31 | 122 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 123 | break; |
ad55cd03 | 124 | case PAM_ERROR_MSG: |
a5c9cd31 | 125 | case PAM_TEXT_INFO: |
ad55cd03 | 126 | if ((*msg)[count].msg != NULL) { |
e11aab29 | 127 | message_cat(&__pam_msg, |
5c377b3b | 128 | PAM_MSG_MEMBER(msg, count, msg)); |
ad55cd03 | 129 | } |
a5c9cd31 | 130 | reply[count].resp = xstrdup(""); |
ad55cd03 | 131 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 132 | break; |
a5c9cd31 | 133 | default: |
134 | free(reply); | |
135 | return PAM_CONV_ERR; | |
5c377b3b | 136 | } |
137 | } else { | |
138 | /* | |
139 | * stdio is connected, so interact directly | |
140 | */ | |
141 | switch(PAM_MSG_MEMBER(msg, count, msg_style)) { | |
142 | case PAM_PROMPT_ECHO_ON: | |
143 | fputs(PAM_MSG_MEMBER(msg, count, msg), stderr); | |
144 | fgets(buf, sizeof(buf), stdin); | |
145 | reply[count].resp = xstrdup(buf); | |
146 | reply[count].resp_retcode = PAM_SUCCESS; | |
147 | break; | |
148 | case PAM_PROMPT_ECHO_OFF: | |
9678565b | 149 | reply[count].resp = |
840ad55e | 150 | read_passphrase(PAM_MSG_MEMBER(msg, count, |
151 | msg), RP_ALLOW_STDIN); | |
5c377b3b | 152 | reply[count].resp_retcode = PAM_SUCCESS; |
153 | break; | |
154 | case PAM_ERROR_MSG: | |
155 | case PAM_TEXT_INFO: | |
156 | if ((*msg)[count].msg != NULL) | |
157 | fprintf(stderr, "%s\n", | |
158 | PAM_MSG_MEMBER(msg, count, msg)); | |
159 | reply[count].resp = xstrdup(""); | |
160 | reply[count].resp_retcode = PAM_SUCCESS; | |
161 | break; | |
162 | default: | |
163 | free(reply); | |
164 | return PAM_CONV_ERR; | |
165 | } | |
a5c9cd31 | 166 | } |
167 | } | |
168 | ||
169 | *resp = reply; | |
170 | ||
171 | return PAM_SUCCESS; | |
172 | } | |
173 | ||
174 | /* Called at exit to cleanly shutdown PAM */ | |
e11aab29 | 175 | void do_pam_cleanup_proc(void *context) |
a5c9cd31 | 176 | { |
37eadb90 | 177 | int pam_retval = PAM_SUCCESS; |
a5c9cd31 | 178 | |
e11aab29 | 179 | if (__pamh && session_opened) { |
180 | pam_retval = pam_close_session(__pamh, 0); | |
5c377b3b | 181 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 182 | log("Cannot close PAM session[%d]: %.200s", |
e11aab29 | 183 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 184 | } |
a5c9cd31 | 185 | |
e11aab29 | 186 | if (__pamh && creds_set) { |
187 | pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED); | |
5c377b3b | 188 | if (pam_retval != PAM_SUCCESS) |
189 | debug("Cannot delete credentials[%d]: %.200s", | |
e11aab29 | 190 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 191 | } |
a5c9cd31 | 192 | |
e11aab29 | 193 | if (__pamh) { |
194 | pam_retval = pam_end(__pamh, pam_retval); | |
5c377b3b | 195 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 196 | log("Cannot release PAM authentication[%d]: %.200s", |
e11aab29 | 197 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 198 | } |
199 | } | |
200 | ||
201 | /* Attempt password authentation using PAM */ | |
202 | int auth_pam_password(struct passwd *pw, const char *password) | |
203 | { | |
204 | extern ServerOptions options; | |
205 | int pam_retval; | |
206 | ||
e11aab29 | 207 | do_pam_set_conv(&conv); |
8c9fe09e | 208 | |
a5c9cd31 | 209 | /* deny if no user. */ |
210 | if (pw == NULL) | |
211 | return 0; | |
3cc990d7 | 212 | if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD) |
a5c9cd31 | 213 | return 0; |
214 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
215 | return 0; | |
216 | ||
e11aab29 | 217 | __pampasswd = password; |
2b87da3b | 218 | |
ad55cd03 | 219 | pamstate = INITIAL_LOGIN; |
78afd1dc | 220 | pam_retval = do_pam_authenticate( |
221 | options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0); | |
a5c9cd31 | 222 | if (pam_retval == PAM_SUCCESS) { |
5c377b3b | 223 | debug("PAM Password authentication accepted for " |
224 | "user \"%.100s\"", pw->pw_name); | |
a5c9cd31 | 225 | return 1; |
226 | } else { | |
5c377b3b | 227 | debug("PAM Password authentication for \"%.100s\" " |
228 | "failed[%d]: %s", pw->pw_name, pam_retval, | |
e11aab29 | 229 | PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 230 | return 0; |
231 | } | |
232 | } | |
233 | ||
234 | /* Do account management using PAM */ | |
235 | int do_pam_account(char *username, char *remote_user) | |
236 | { | |
237 | int pam_retval; | |
2b87da3b | 238 | |
e11aab29 | 239 | do_pam_set_conv(&conv); |
5c377b3b | 240 | |
5c377b3b | 241 | if (remote_user) { |
a5c9cd31 | 242 | debug("PAM setting ruser to \"%.200s\"", remote_user); |
e11aab29 | 243 | pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user); |
5c377b3b | 244 | if (pam_retval != PAM_SUCCESS) |
245 | fatal("PAM set ruser failed[%d]: %.200s", pam_retval, | |
e11aab29 | 246 | PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 247 | } |
248 | ||
e11aab29 | 249 | pam_retval = pam_acct_mgmt(__pamh, 0); |
5daf7064 | 250 | switch (pam_retval) { |
251 | case PAM_SUCCESS: | |
252 | /* This is what we want */ | |
253 | break; | |
254 | case PAM_NEW_AUTHTOK_REQD: | |
e11aab29 | 255 | message_cat(&__pam_msg, NEW_AUTHTOK_MSG); |
ad55cd03 | 256 | /* flag that password change is necessary */ |
257 | password_change_required = 1; | |
5daf7064 | 258 | break; |
259 | default: | |
5c377b3b | 260 | log("PAM rejected by account configuration[%d]: " |
e11aab29 | 261 | "%.200s", pam_retval, PAM_STRERROR(__pamh, |
5c377b3b | 262 | pam_retval)); |
5daf7064 | 263 | return(0); |
a5c9cd31 | 264 | } |
2b87da3b | 265 | |
a5c9cd31 | 266 | return(1); |
267 | } | |
268 | ||
269 | /* Do PAM-specific session initialisation */ | |
fd094f49 | 270 | void do_pam_session(char *username, const char *ttyname) |
a5c9cd31 | 271 | { |
272 | int pam_retval; | |
273 | ||
5f404be3 | 274 | do_pam_set_conv(&conv); |
275 | ||
a5c9cd31 | 276 | if (ttyname != NULL) { |
277 | debug("PAM setting tty to \"%.200s\"", ttyname); | |
e11aab29 | 278 | pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname); |
5c377b3b | 279 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 280 | fatal("PAM set tty failed[%d]: %.200s", |
e11aab29 | 281 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 282 | } |
283 | ||
e11aab29 | 284 | pam_retval = pam_open_session(__pamh, 0); |
5c377b3b | 285 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 286 | fatal("PAM session setup failed[%d]: %.200s", |
e11aab29 | 287 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
40a35ff1 | 288 | |
1c2d0a13 | 289 | session_opened = 1; |
a5c9cd31 | 290 | } |
291 | ||
2b87da3b | 292 | /* Set PAM credentials */ |
9afbfcfa | 293 | void do_pam_setcred(int init) |
a5c9cd31 | 294 | { |
295 | int pam_retval; | |
2b87da3b | 296 | |
5f404be3 | 297 | do_pam_set_conv(&conv); |
298 | ||
a5c9cd31 | 299 | debug("PAM establishing creds"); |
9afbfcfa | 300 | pam_retval = pam_setcred(__pamh, |
301 | init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED); | |
5daf7064 | 302 | if (pam_retval != PAM_SUCCESS) { |
5c377b3b | 303 | if (was_authenticated) |
2b87da3b | 304 | fatal("PAM setcred failed[%d]: %.200s", |
e11aab29 | 305 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
5c377b3b | 306 | else |
2b87da3b | 307 | debug("PAM setcred failed[%d]: %.200s", |
e11aab29 | 308 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 309 | } else |
310 | creds_set = 1; | |
ad55cd03 | 311 | } |
312 | ||
2919e060 | 313 | /* accessor function for file scope static variable */ |
e11aab29 | 314 | int is_pam_password_change_required(void) |
2919e060 | 315 | { |
316 | return password_change_required; | |
317 | } | |
318 | ||
2b87da3b | 319 | /* |
ad55cd03 | 320 | * Have user change authentication token if pam_acct_mgmt() indicated |
321 | * it was expired. This needs to be called after an interactive | |
322 | * session is established and the user's pty is connected to | |
323 | * stdin/stout/stderr. | |
324 | */ | |
a815d7a3 | 325 | void do_pam_chauthtok(void) |
ad55cd03 | 326 | { |
327 | int pam_retval; | |
328 | ||
5f404be3 | 329 | do_pam_set_conv(&conv); |
330 | ||
ad55cd03 | 331 | if (password_change_required) { |
332 | pamstate = OTHER; | |
0a3700ee | 333 | pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK); |
334 | if (pam_retval != PAM_SUCCESS) | |
335 | fatal("PAM pam_chauthtok failed[%d]: %.200s", | |
336 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); | |
5daf7064 | 337 | } |
a5c9cd31 | 338 | } |
339 | ||
340 | /* Cleanly shutdown PAM */ | |
341 | void finish_pam(void) | |
342 | { | |
e11aab29 | 343 | do_pam_cleanup_proc(NULL); |
344 | fatal_remove_cleanup(&do_pam_cleanup_proc, NULL); | |
a5c9cd31 | 345 | } |
346 | ||
347 | /* Start PAM authentication for specified account */ | |
04fc7a67 | 348 | void start_pam(const char *user) |
a5c9cd31 | 349 | { |
350 | int pam_retval; | |
dbd97a4d | 351 | extern ServerOptions options; |
46c76c63 | 352 | extern u_int utmp_len; |
353 | const char *rhost; | |
a5c9cd31 | 354 | |
04fc7a67 | 355 | debug("Starting up PAM with username \"%.200s\"", user); |
a5c9cd31 | 356 | |
e11aab29 | 357 | pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh); |
a5c9cd31 | 358 | |
5c377b3b | 359 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 360 | fatal("PAM initialisation failed[%d]: %.200s", |
e11aab29 | 361 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
e275684f | 362 | |
983784a1 | 363 | rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping); |
46c76c63 | 364 | debug("PAM setting rhost to \"%.200s\"", rhost); |
365 | ||
366 | pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost); | |
e275684f | 367 | if (pam_retval != PAM_SUCCESS) |
368 | fatal("PAM set rhost failed[%d]: %.200s", pam_retval, | |
e11aab29 | 369 | PAM_STRERROR(__pamh, pam_retval)); |
a8545c6c | 370 | #ifdef PAM_TTY_KLUDGE |
ae543aaa | 371 | /* |
372 | * Some PAM modules (e.g. pam_time) require a TTY to operate, | |
2b87da3b | 373 | * and will fail in various stupid ways if they don't get one. |
ae543aaa | 374 | * sshd doesn't set the tty until too late in the auth process and may |
375 | * not even need one (for tty-less connections) | |
2b87da3b | 376 | * Kludge: Set a fake PAM_TTY |
ae543aaa | 377 | */ |
9f214051 | 378 | pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh"); |
5c377b3b | 379 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 380 | fatal("PAM set tty failed[%d]: %.200s", |
e11aab29 | 381 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a8545c6c | 382 | #endif /* PAM_TTY_KLUDGE */ |
cbd7492e | 383 | |
e11aab29 | 384 | fatal_add_cleanup(&do_pam_cleanup_proc, NULL); |
a5c9cd31 | 385 | } |
386 | ||
387 | /* Return list of PAM enviornment strings */ | |
388 | char **fetch_pam_environment(void) | |
389 | { | |
2b763e31 | 390 | #ifdef HAVE_PAM_GETENVLIST |
e11aab29 | 391 | return(pam_getenvlist(__pamh)); |
2b763e31 | 392 | #else /* HAVE_PAM_GETENVLIST */ |
393 | return(NULL); | |
394 | #endif /* HAVE_PAM_GETENVLIST */ | |
a5c9cd31 | 395 | } |
396 | ||
397 | /* Print any messages that have been generated during authentication */ | |
398 | /* or account checking to stderr */ | |
399 | void print_pam_messages(void) | |
400 | { | |
e11aab29 | 401 | if (__pam_msg != NULL) |
402 | fputs(__pam_msg, stderr); | |
5daf7064 | 403 | } |
404 | ||
5c377b3b | 405 | /* Append a message to buffer */ |
406 | void message_cat(char **p, const char *a) | |
5daf7064 | 407 | { |
5c377b3b | 408 | char *cp; |
409 | size_t new_len; | |
2b87da3b | 410 | |
5c377b3b | 411 | new_len = strlen(a); |
2b87da3b | 412 | |
5c377b3b | 413 | if (*p) { |
414 | size_t len = strlen(*p); | |
415 | ||
416 | *p = xrealloc(*p, new_len + len + 2); | |
417 | cp = *p + len; | |
418 | } else | |
419 | *p = cp = xmalloc(new_len + 2); | |
5daf7064 | 420 | |
5c377b3b | 421 | memcpy(cp, a, new_len); |
422 | cp[new_len] = '\n'; | |
423 | cp[new_len + 1] = '\0'; | |
a5c9cd31 | 424 | } |
425 | ||
426 | #endif /* USE_PAM */ |