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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" |
fde58bd4 | 31 | #include "auth.h" |
5c377b3b | 32 | #include "auth-pam.h" |
a5c9cd31 | 33 | #include "servconf.h" |
42f11eb2 | 34 | #include "canohost.h" |
35 | #include "readpass.h" | |
a5c9cd31 | 36 | |
1ddee76b | 37 | extern char *__progname; |
38 | ||
a5c9cd31 | 39 | RCSID("$Id$"); |
40 | ||
5daf7064 | 41 | #define NEW_AUTHTOK_MSG \ |
ad55cd03 | 42 | "Warning: Your password has expired, please change it now" |
5daf7064 | 43 | |
5c377b3b | 44 | static int do_pam_conversation(int num_msg, const struct pam_message **msg, |
45 | struct pam_response **resp, void *appdata_ptr); | |
a5c9cd31 | 46 | |
47 | /* module-local variables */ | |
48 | static struct pam_conv conv = { | |
5c377b3b | 49 | do_pam_conversation, |
a5c9cd31 | 50 | NULL |
51 | }; | |
e11aab29 | 52 | static char *__pam_msg = NULL; |
53 | static pam_handle_t *__pamh = NULL; | |
54 | static const char *__pampasswd = NULL; | |
a5c9cd31 | 55 | |
5c377b3b | 56 | /* states for do_pam_conversation() */ |
8c9fe09e | 57 | enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN; |
ad55cd03 | 58 | /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_REQD */ |
59 | static int password_change_required = 0; | |
8c9fe09e | 60 | /* remember whether the last pam_authenticate() succeeded or not */ |
61 | static int was_authenticated = 0; | |
62 | ||
e11aab29 | 63 | /* Remember what has been initialised */ |
64 | static int session_opened = 0; | |
65 | static int creds_set = 0; | |
66 | ||
8c9fe09e | 67 | /* accessor which allows us to switch conversation structs according to |
68 | * the authentication method being used */ | |
e11aab29 | 69 | void do_pam_set_conv(struct pam_conv *conv) |
8c9fe09e | 70 | { |
e11aab29 | 71 | pam_set_item(__pamh, PAM_CONV, conv); |
8c9fe09e | 72 | } |
73 | ||
74 | /* start an authentication run */ | |
75 | int do_pam_authenticate(int flags) | |
76 | { | |
e11aab29 | 77 | int retval = pam_authenticate(__pamh, flags); |
8c9fe09e | 78 | was_authenticated = (retval == PAM_SUCCESS); |
79 | return retval; | |
80 | } | |
ad55cd03 | 81 | |
82 | /* | |
83 | * PAM conversation function. | |
84 | * There are two states this can run in. | |
85 | * | |
86 | * INITIAL_LOGIN mode simply feeds the password from the client into | |
87 | * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output | |
e11aab29 | 88 | * messages with into __pam_msg. This is used during initial |
ad55cd03 | 89 | * authentication to bypass the normal PAM password prompt. |
90 | * | |
9678565b | 91 | * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase() |
ad55cd03 | 92 | * and outputs messages to stderr. This mode is used if pam_chauthtok() |
93 | * is called to update expired passwords. | |
94 | */ | |
5c377b3b | 95 | static int do_pam_conversation(int num_msg, const struct pam_message **msg, |
a5c9cd31 | 96 | struct pam_response **resp, void *appdata_ptr) |
97 | { | |
98 | struct pam_response *reply; | |
99 | int count; | |
ad55cd03 | 100 | char buf[1024]; |
a5c9cd31 | 101 | |
102 | /* PAM will free this later */ | |
103 | reply = malloc(num_msg * sizeof(*reply)); | |
104 | if (reply == NULL) | |
2b87da3b | 105 | return PAM_CONV_ERR; |
a5c9cd31 | 106 | |
ad55cd03 | 107 | for (count = 0; count < num_msg; count++) { |
5c377b3b | 108 | if (pamstate == INITIAL_LOGIN) { |
109 | /* | |
110 | * We can't use stdio yet, queue messages for | |
111 | * printing later | |
112 | */ | |
113 | switch(PAM_MSG_MEMBER(msg, count, msg_style)) { | |
ad55cd03 | 114 | case PAM_PROMPT_ECHO_ON: |
5c377b3b | 115 | free(reply); |
116 | return PAM_CONV_ERR; | |
117 | case PAM_PROMPT_ECHO_OFF: | |
e11aab29 | 118 | if (__pampasswd == NULL) { |
71dfaf1c | 119 | free(reply); |
120 | return PAM_CONV_ERR; | |
71dfaf1c | 121 | } |
e11aab29 | 122 | reply[count].resp = xstrdup(__pampasswd); |
a5c9cd31 | 123 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 124 | break; |
ad55cd03 | 125 | case PAM_ERROR_MSG: |
a5c9cd31 | 126 | case PAM_TEXT_INFO: |
ad55cd03 | 127 | if ((*msg)[count].msg != NULL) { |
e11aab29 | 128 | message_cat(&__pam_msg, |
5c377b3b | 129 | PAM_MSG_MEMBER(msg, count, msg)); |
ad55cd03 | 130 | } |
a5c9cd31 | 131 | reply[count].resp = xstrdup(""); |
ad55cd03 | 132 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 133 | break; |
a5c9cd31 | 134 | default: |
135 | free(reply); | |
136 | return PAM_CONV_ERR; | |
5c377b3b | 137 | } |
138 | } else { | |
139 | /* | |
140 | * stdio is connected, so interact directly | |
141 | */ | |
142 | switch(PAM_MSG_MEMBER(msg, count, msg_style)) { | |
143 | case PAM_PROMPT_ECHO_ON: | |
144 | fputs(PAM_MSG_MEMBER(msg, count, msg), stderr); | |
145 | fgets(buf, sizeof(buf), stdin); | |
146 | reply[count].resp = xstrdup(buf); | |
147 | reply[count].resp_retcode = PAM_SUCCESS; | |
148 | break; | |
149 | case PAM_PROMPT_ECHO_OFF: | |
9678565b | 150 | reply[count].resp = |
840ad55e | 151 | read_passphrase(PAM_MSG_MEMBER(msg, count, |
152 | msg), RP_ALLOW_STDIN); | |
5c377b3b | 153 | reply[count].resp_retcode = PAM_SUCCESS; |
154 | break; | |
155 | case PAM_ERROR_MSG: | |
156 | case PAM_TEXT_INFO: | |
157 | if ((*msg)[count].msg != NULL) | |
158 | fprintf(stderr, "%s\n", | |
159 | PAM_MSG_MEMBER(msg, count, msg)); | |
160 | reply[count].resp = xstrdup(""); | |
161 | reply[count].resp_retcode = PAM_SUCCESS; | |
162 | break; | |
163 | default: | |
164 | free(reply); | |
165 | return PAM_CONV_ERR; | |
166 | } | |
a5c9cd31 | 167 | } |
168 | } | |
169 | ||
170 | *resp = reply; | |
171 | ||
172 | return PAM_SUCCESS; | |
173 | } | |
174 | ||
175 | /* Called at exit to cleanly shutdown PAM */ | |
e11aab29 | 176 | void do_pam_cleanup_proc(void *context) |
a5c9cd31 | 177 | { |
37eadb90 | 178 | int pam_retval = PAM_SUCCESS; |
a5c9cd31 | 179 | |
e11aab29 | 180 | if (__pamh && session_opened) { |
181 | pam_retval = pam_close_session(__pamh, 0); | |
5c377b3b | 182 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 183 | log("Cannot close PAM session[%d]: %.200s", |
e11aab29 | 184 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 185 | } |
a5c9cd31 | 186 | |
e11aab29 | 187 | if (__pamh && creds_set) { |
188 | pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED); | |
5c377b3b | 189 | if (pam_retval != PAM_SUCCESS) |
190 | debug("Cannot delete credentials[%d]: %.200s", | |
e11aab29 | 191 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 192 | } |
a5c9cd31 | 193 | |
e11aab29 | 194 | if (__pamh) { |
195 | pam_retval = pam_end(__pamh, pam_retval); | |
5c377b3b | 196 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 197 | log("Cannot release PAM authentication[%d]: %.200s", |
e11aab29 | 198 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 199 | } |
200 | } | |
201 | ||
202 | /* Attempt password authentation using PAM */ | |
fde58bd4 | 203 | int auth_pam_password(Authctxt *authctxt, const char *password) |
a5c9cd31 | 204 | { |
205 | extern ServerOptions options; | |
206 | int pam_retval; | |
fde58bd4 | 207 | struct passwd *pw = authctxt->pw; |
a5c9cd31 | 208 | |
e11aab29 | 209 | do_pam_set_conv(&conv); |
8c9fe09e | 210 | |
a5c9cd31 | 211 | /* deny if no user. */ |
212 | if (pw == NULL) | |
213 | return 0; | |
3cc990d7 | 214 | if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD) |
a5c9cd31 | 215 | return 0; |
216 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
217 | return 0; | |
218 | ||
e11aab29 | 219 | __pampasswd = password; |
2b87da3b | 220 | |
ad55cd03 | 221 | pamstate = INITIAL_LOGIN; |
78afd1dc | 222 | pam_retval = do_pam_authenticate( |
223 | options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0); | |
a5c9cd31 | 224 | if (pam_retval == PAM_SUCCESS) { |
5c377b3b | 225 | debug("PAM Password authentication accepted for " |
226 | "user \"%.100s\"", pw->pw_name); | |
a5c9cd31 | 227 | return 1; |
228 | } else { | |
5c377b3b | 229 | debug("PAM Password authentication for \"%.100s\" " |
230 | "failed[%d]: %s", pw->pw_name, pam_retval, | |
e11aab29 | 231 | PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 232 | return 0; |
233 | } | |
234 | } | |
235 | ||
236 | /* Do account management using PAM */ | |
237 | int do_pam_account(char *username, char *remote_user) | |
238 | { | |
239 | int pam_retval; | |
2b87da3b | 240 | |
e11aab29 | 241 | do_pam_set_conv(&conv); |
5c377b3b | 242 | |
5c377b3b | 243 | if (remote_user) { |
a5c9cd31 | 244 | debug("PAM setting ruser to \"%.200s\"", remote_user); |
e11aab29 | 245 | pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user); |
5c377b3b | 246 | if (pam_retval != PAM_SUCCESS) |
247 | fatal("PAM set ruser failed[%d]: %.200s", pam_retval, | |
e11aab29 | 248 | PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 249 | } |
250 | ||
e11aab29 | 251 | pam_retval = pam_acct_mgmt(__pamh, 0); |
ad200abb | 252 | debug2("pam_acct_mgmt() = %d", pam_retval); |
5daf7064 | 253 | switch (pam_retval) { |
254 | case PAM_SUCCESS: | |
255 | /* This is what we want */ | |
256 | break; | |
e108cd93 | 257 | #if 0 |
5daf7064 | 258 | case PAM_NEW_AUTHTOK_REQD: |
e11aab29 | 259 | message_cat(&__pam_msg, NEW_AUTHTOK_MSG); |
ad55cd03 | 260 | /* flag that password change is necessary */ |
261 | password_change_required = 1; | |
5daf7064 | 262 | break; |
e108cd93 | 263 | #endif |
5daf7064 | 264 | default: |
5c377b3b | 265 | log("PAM rejected by account configuration[%d]: " |
e11aab29 | 266 | "%.200s", pam_retval, PAM_STRERROR(__pamh, |
5c377b3b | 267 | pam_retval)); |
5daf7064 | 268 | return(0); |
a5c9cd31 | 269 | } |
2b87da3b | 270 | |
a5c9cd31 | 271 | return(1); |
272 | } | |
273 | ||
274 | /* Do PAM-specific session initialisation */ | |
fd094f49 | 275 | void do_pam_session(char *username, const char *ttyname) |
a5c9cd31 | 276 | { |
277 | int pam_retval; | |
278 | ||
5f404be3 | 279 | do_pam_set_conv(&conv); |
280 | ||
a5c9cd31 | 281 | if (ttyname != NULL) { |
282 | debug("PAM setting tty to \"%.200s\"", ttyname); | |
e11aab29 | 283 | pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname); |
5c377b3b | 284 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 285 | fatal("PAM set tty failed[%d]: %.200s", |
e11aab29 | 286 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a5c9cd31 | 287 | } |
288 | ||
e11aab29 | 289 | pam_retval = pam_open_session(__pamh, 0); |
5c377b3b | 290 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 291 | fatal("PAM session setup failed[%d]: %.200s", |
e11aab29 | 292 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
40a35ff1 | 293 | |
1c2d0a13 | 294 | session_opened = 1; |
a5c9cd31 | 295 | } |
296 | ||
2b87da3b | 297 | /* Set PAM credentials */ |
9afbfcfa | 298 | void do_pam_setcred(int init) |
a5c9cd31 | 299 | { |
300 | int pam_retval; | |
2b87da3b | 301 | |
5f404be3 | 302 | do_pam_set_conv(&conv); |
303 | ||
a5c9cd31 | 304 | debug("PAM establishing creds"); |
9afbfcfa | 305 | pam_retval = pam_setcred(__pamh, |
306 | init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED); | |
5daf7064 | 307 | if (pam_retval != PAM_SUCCESS) { |
5c377b3b | 308 | if (was_authenticated) |
2b87da3b | 309 | fatal("PAM setcred failed[%d]: %.200s", |
e11aab29 | 310 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
5c377b3b | 311 | else |
2b87da3b | 312 | debug("PAM setcred failed[%d]: %.200s", |
e11aab29 | 313 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
1c2d0a13 | 314 | } else |
315 | creds_set = 1; | |
ad55cd03 | 316 | } |
317 | ||
2919e060 | 318 | /* accessor function for file scope static variable */ |
e11aab29 | 319 | int is_pam_password_change_required(void) |
2919e060 | 320 | { |
321 | return password_change_required; | |
322 | } | |
323 | ||
2b87da3b | 324 | /* |
ad55cd03 | 325 | * Have user change authentication token if pam_acct_mgmt() indicated |
326 | * it was expired. This needs to be called after an interactive | |
327 | * session is established and the user's pty is connected to | |
328 | * stdin/stout/stderr. | |
329 | */ | |
a815d7a3 | 330 | void do_pam_chauthtok(void) |
ad55cd03 | 331 | { |
332 | int pam_retval; | |
333 | ||
5f404be3 | 334 | do_pam_set_conv(&conv); |
335 | ||
ad55cd03 | 336 | if (password_change_required) { |
337 | pamstate = OTHER; | |
0a3700ee | 338 | pam_retval = pam_chauthtok(__pamh, PAM_CHANGE_EXPIRED_AUTHTOK); |
339 | if (pam_retval != PAM_SUCCESS) | |
340 | fatal("PAM pam_chauthtok failed[%d]: %.200s", | |
341 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); | |
5daf7064 | 342 | } |
a5c9cd31 | 343 | } |
344 | ||
345 | /* Cleanly shutdown PAM */ | |
346 | void finish_pam(void) | |
347 | { | |
e11aab29 | 348 | do_pam_cleanup_proc(NULL); |
349 | fatal_remove_cleanup(&do_pam_cleanup_proc, NULL); | |
a5c9cd31 | 350 | } |
351 | ||
352 | /* Start PAM authentication for specified account */ | |
04fc7a67 | 353 | void start_pam(const char *user) |
a5c9cd31 | 354 | { |
355 | int pam_retval; | |
dbd97a4d | 356 | extern ServerOptions options; |
46c76c63 | 357 | extern u_int utmp_len; |
358 | const char *rhost; | |
a5c9cd31 | 359 | |
04fc7a67 | 360 | debug("Starting up PAM with username \"%.200s\"", user); |
a5c9cd31 | 361 | |
e11aab29 | 362 | pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh); |
a5c9cd31 | 363 | |
5c377b3b | 364 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 365 | fatal("PAM initialisation failed[%d]: %.200s", |
e11aab29 | 366 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
e275684f | 367 | |
983784a1 | 368 | rhost = get_remote_name_or_ip(utmp_len, options.verify_reverse_mapping); |
46c76c63 | 369 | debug("PAM setting rhost to \"%.200s\"", rhost); |
370 | ||
371 | pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost); | |
e275684f | 372 | if (pam_retval != PAM_SUCCESS) |
373 | fatal("PAM set rhost failed[%d]: %.200s", pam_retval, | |
e11aab29 | 374 | PAM_STRERROR(__pamh, pam_retval)); |
a8545c6c | 375 | #ifdef PAM_TTY_KLUDGE |
ae543aaa | 376 | /* |
377 | * Some PAM modules (e.g. pam_time) require a TTY to operate, | |
2b87da3b | 378 | * and will fail in various stupid ways if they don't get one. |
ae543aaa | 379 | * sshd doesn't set the tty until too late in the auth process and may |
380 | * not even need one (for tty-less connections) | |
2b87da3b | 381 | * Kludge: Set a fake PAM_TTY |
ae543aaa | 382 | */ |
9f214051 | 383 | pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh"); |
5c377b3b | 384 | if (pam_retval != PAM_SUCCESS) |
2b87da3b | 385 | fatal("PAM set tty failed[%d]: %.200s", |
e11aab29 | 386 | pam_retval, PAM_STRERROR(__pamh, pam_retval)); |
a8545c6c | 387 | #endif /* PAM_TTY_KLUDGE */ |
cbd7492e | 388 | |
e11aab29 | 389 | fatal_add_cleanup(&do_pam_cleanup_proc, NULL); |
a5c9cd31 | 390 | } |
391 | ||
392 | /* Return list of PAM enviornment strings */ | |
393 | char **fetch_pam_environment(void) | |
394 | { | |
2b763e31 | 395 | #ifdef HAVE_PAM_GETENVLIST |
e11aab29 | 396 | return(pam_getenvlist(__pamh)); |
2b763e31 | 397 | #else /* HAVE_PAM_GETENVLIST */ |
398 | return(NULL); | |
399 | #endif /* HAVE_PAM_GETENVLIST */ | |
a5c9cd31 | 400 | } |
401 | ||
402 | /* Print any messages that have been generated during authentication */ | |
403 | /* or account checking to stderr */ | |
404 | void print_pam_messages(void) | |
405 | { | |
e11aab29 | 406 | if (__pam_msg != NULL) |
407 | fputs(__pam_msg, stderr); | |
5daf7064 | 408 | } |
409 | ||
5c377b3b | 410 | /* Append a message to buffer */ |
411 | void message_cat(char **p, const char *a) | |
5daf7064 | 412 | { |
5c377b3b | 413 | char *cp; |
414 | size_t new_len; | |
2b87da3b | 415 | |
5c377b3b | 416 | new_len = strlen(a); |
2b87da3b | 417 | |
5c377b3b | 418 | if (*p) { |
419 | size_t len = strlen(*p); | |
420 | ||
421 | *p = xrealloc(*p, new_len + len + 2); | |
422 | cp = *p + len; | |
423 | } else | |
424 | *p = cp = xmalloc(new_len + 2); | |
5daf7064 | 425 | |
5c377b3b | 426 | memcpy(cp, a, new_len); |
427 | cp[new_len] = '\n'; | |
428 | cp[new_len + 1] = '\0'; | |
a5c9cd31 | 429 | } |
430 | ||
431 | #endif /* USE_PAM */ |