]>
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" | |
30 | #include "servconf.h" | |
31 | ||
32 | RCSID("$Id$"); | |
33 | ||
5daf7064 | 34 | #define NEW_AUTHTOK_MSG \ |
ad55cd03 | 35 | "Warning: Your password has expired, please change it now" |
5daf7064 | 36 | |
a5c9cd31 | 37 | /* Callbacks */ |
38 | static int pamconv(int num_msg, const struct pam_message **msg, | |
39 | struct pam_response **resp, void *appdata_ptr); | |
40 | void pam_cleanup_proc(void *context); | |
5daf7064 | 41 | void pam_msg_cat(const char *msg); |
a5c9cd31 | 42 | |
43 | /* module-local variables */ | |
44 | static struct pam_conv conv = { | |
45 | pamconv, | |
46 | NULL | |
47 | }; | |
ad55cd03 | 48 | static pam_handle_t *pamh = NULL; |
a5c9cd31 | 49 | static const char *pampasswd = NULL; |
5daf7064 | 50 | static char *pam_msg = NULL; |
a5c9cd31 | 51 | |
ad55cd03 | 52 | /* states for pamconv() */ |
53 | typedef enum { INITIAL_LOGIN, OTHER } pamstates; | |
54 | static pamstates pamstate = INITIAL_LOGIN; | |
55 | /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_REQD */ | |
56 | static int password_change_required = 0; | |
57 | ||
58 | /* | |
59 | * PAM conversation function. | |
60 | * There are two states this can run in. | |
61 | * | |
62 | * INITIAL_LOGIN mode simply feeds the password from the client into | |
63 | * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output | |
64 | * messages with pam_msg_cat(). This is used during initial | |
65 | * authentication to bypass the normal PAM password prompt. | |
66 | * | |
67 | * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase(prompt, 1) | |
68 | * and outputs messages to stderr. This mode is used if pam_chauthtok() | |
69 | * is called to update expired passwords. | |
70 | */ | |
a5c9cd31 | 71 | static int pamconv(int num_msg, const struct pam_message **msg, |
72 | struct pam_response **resp, void *appdata_ptr) | |
73 | { | |
74 | struct pam_response *reply; | |
75 | int count; | |
ad55cd03 | 76 | char buf[1024]; |
a5c9cd31 | 77 | |
78 | /* PAM will free this later */ | |
79 | reply = malloc(num_msg * sizeof(*reply)); | |
80 | if (reply == NULL) | |
81 | return PAM_CONV_ERR; | |
82 | ||
ad55cd03 | 83 | for (count = 0; count < num_msg; count++) { |
84 | switch ((*msg)[count].msg_style) { | |
85 | case PAM_PROMPT_ECHO_ON: | |
86 | fputs((*msg)[count].msg, stderr); | |
87 | fgets(buf, sizeof(buf), stdin); | |
88 | reply[count].resp = xstrdup(buf); | |
89 | reply[count].resp_retcode = PAM_SUCCESS; | |
90 | break; | |
a5c9cd31 | 91 | case PAM_PROMPT_ECHO_OFF: |
ad55cd03 | 92 | if (pamstate == INITIAL_LOGIN) { |
93 | if (pampasswd == NULL) { | |
94 | free(reply); | |
95 | return PAM_CONV_ERR; | |
96 | } | |
97 | reply[count].resp = xstrdup(pampasswd); | |
98 | } else | |
99 | reply[count].resp = xstrdup(read_passphrase((*msg)[count].msg, 1)); | |
a5c9cd31 | 100 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 101 | break; |
ad55cd03 | 102 | case PAM_ERROR_MSG: |
a5c9cd31 | 103 | case PAM_TEXT_INFO: |
ad55cd03 | 104 | if ((*msg)[count].msg != NULL) { |
105 | if (pamstate == INITIAL_LOGIN) | |
106 | pam_msg_cat((*msg)[count].msg); | |
107 | else { | |
108 | fputs((*msg)[count].msg, stderr); | |
109 | fputs("\n", stderr); | |
110 | } | |
111 | } | |
a5c9cd31 | 112 | reply[count].resp = xstrdup(""); |
ad55cd03 | 113 | reply[count].resp_retcode = PAM_SUCCESS; |
a5c9cd31 | 114 | break; |
a5c9cd31 | 115 | default: |
116 | free(reply); | |
117 | return PAM_CONV_ERR; | |
118 | } | |
119 | } | |
120 | ||
121 | *resp = reply; | |
122 | ||
123 | return PAM_SUCCESS; | |
124 | } | |
125 | ||
126 | /* Called at exit to cleanly shutdown PAM */ | |
127 | void pam_cleanup_proc(void *context) | |
128 | { | |
129 | int pam_retval; | |
130 | ||
131 | if (pamh != NULL) | |
132 | { | |
ad55cd03 | 133 | pam_retval = pam_close_session(pamh, 0); |
a5c9cd31 | 134 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 135 | log("Cannot close PAM session[%d]: %.200s", |
136 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 137 | } |
138 | ||
ad55cd03 | 139 | pam_retval = pam_setcred(pamh, PAM_DELETE_CRED); |
a5c9cd31 | 140 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 141 | debug("Cannot delete credentials[%d]: %.200s", |
142 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 143 | } |
144 | ||
ad55cd03 | 145 | pam_retval = pam_end(pamh, pam_retval); |
a5c9cd31 | 146 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 147 | log("Cannot release PAM authentication[%d]: %.200s", |
148 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 149 | } |
150 | } | |
151 | } | |
152 | ||
153 | /* Attempt password authentation using PAM */ | |
154 | int auth_pam_password(struct passwd *pw, const char *password) | |
155 | { | |
156 | extern ServerOptions options; | |
157 | int pam_retval; | |
158 | ||
159 | /* deny if no user. */ | |
160 | if (pw == NULL) | |
161 | return 0; | |
162 | if (pw->pw_uid == 0 && options.permit_root_login == 2) | |
163 | return 0; | |
164 | if (*password == '\0' && options.permit_empty_passwd == 0) | |
165 | return 0; | |
166 | ||
167 | pampasswd = password; | |
168 | ||
ad55cd03 | 169 | pamstate = INITIAL_LOGIN; |
170 | pam_retval = pam_authenticate(pamh, 0); | |
a5c9cd31 | 171 | if (pam_retval == PAM_SUCCESS) { |
5daf7064 | 172 | debug("PAM Password authentication accepted for user \"%.100s\"", |
173 | pw->pw_name); | |
a5c9cd31 | 174 | return 1; |
175 | } else { | |
ebd782f7 | 176 | debug("PAM Password authentication for \"%.100s\" failed[%d]: %s", |
177 | pw->pw_name, pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 178 | return 0; |
179 | } | |
180 | } | |
181 | ||
182 | /* Do account management using PAM */ | |
183 | int do_pam_account(char *username, char *remote_user) | |
184 | { | |
185 | int pam_retval; | |
5daf7064 | 186 | |
a5c9cd31 | 187 | debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname()); |
ad55cd03 | 188 | pam_retval = pam_set_item(pamh, PAM_RHOST, |
a5c9cd31 | 189 | get_canonical_hostname()); |
190 | if (pam_retval != PAM_SUCCESS) { | |
ebd782f7 | 191 | fatal("PAM set rhost failed[%d]: %.200s", |
192 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 193 | } |
194 | ||
195 | if (remote_user != NULL) { | |
196 | debug("PAM setting ruser to \"%.200s\"", remote_user); | |
ad55cd03 | 197 | pam_retval = pam_set_item(pamh, PAM_RUSER, remote_user); |
a5c9cd31 | 198 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 199 | fatal("PAM set ruser failed[%d]: %.200s", |
200 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
a5c9cd31 | 201 | } |
202 | } | |
203 | ||
ad55cd03 | 204 | pam_retval = pam_acct_mgmt(pamh, 0); |
5daf7064 | 205 | switch (pam_retval) { |
206 | case PAM_SUCCESS: | |
207 | /* This is what we want */ | |
208 | break; | |
209 | case PAM_NEW_AUTHTOK_REQD: | |
210 | pam_msg_cat(NEW_AUTHTOK_MSG); | |
ad55cd03 | 211 | /* flag that password change is necessary */ |
212 | password_change_required = 1; | |
5daf7064 | 213 | break; |
214 | default: | |
ebd782f7 | 215 | log("PAM rejected by account configuration[%d]: %.200s", |
216 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
5daf7064 | 217 | return(0); |
a5c9cd31 | 218 | } |
219 | ||
220 | return(1); | |
221 | } | |
222 | ||
223 | /* Do PAM-specific session initialisation */ | |
fd094f49 | 224 | void do_pam_session(char *username, const char *ttyname) |
a5c9cd31 | 225 | { |
226 | int pam_retval; | |
227 | ||
228 | if (ttyname != NULL) { | |
229 | debug("PAM setting tty to \"%.200s\"", ttyname); | |
ad55cd03 | 230 | pam_retval = pam_set_item(pamh, PAM_TTY, ttyname); |
5daf7064 | 231 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 232 | fatal("PAM set tty failed[%d]: %.200s", |
233 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
5daf7064 | 234 | } |
a5c9cd31 | 235 | } |
236 | ||
ad55cd03 | 237 | pam_retval = pam_open_session(pamh, 0); |
5daf7064 | 238 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 239 | fatal("PAM session setup failed[%d]: %.200s", |
240 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
5daf7064 | 241 | } |
a5c9cd31 | 242 | } |
243 | ||
244 | /* Set PAM credentials */ | |
245 | void do_pam_setcred() | |
246 | { | |
247 | int pam_retval; | |
248 | ||
249 | debug("PAM establishing creds"); | |
ad55cd03 | 250 | pam_retval = pam_setcred(pamh, PAM_ESTABLISH_CRED); |
5daf7064 | 251 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 252 | fatal("PAM setcred failed[%d]: %.200s", |
253 | pam_setcred, PAM_STRERROR(pamh, pam_retval)); | |
ad55cd03 | 254 | } |
255 | } | |
256 | ||
257 | /* | |
258 | * Have user change authentication token if pam_acct_mgmt() indicated | |
259 | * it was expired. This needs to be called after an interactive | |
260 | * session is established and the user's pty is connected to | |
261 | * stdin/stout/stderr. | |
262 | */ | |
263 | void do_pam_chauthtok() | |
264 | { | |
265 | int pam_retval; | |
266 | ||
267 | if (password_change_required) { | |
268 | pamstate = OTHER; | |
ebd782f7 | 269 | /* |
270 | * XXX: should we really loop forever? | |
271 | */ | |
ad55cd03 | 272 | do { |
273 | pam_retval = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK); | |
ebd782f7 | 274 | if (pam_retval != PAM_SUCCESS) { |
275 | log("PAM pam_chauthtok failed[%d]: %.200s", | |
276 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
277 | } | |
ad55cd03 | 278 | } while (pam_retval != PAM_SUCCESS); |
5daf7064 | 279 | } |
a5c9cd31 | 280 | } |
281 | ||
282 | /* Cleanly shutdown PAM */ | |
283 | void finish_pam(void) | |
284 | { | |
285 | pam_cleanup_proc(NULL); | |
286 | fatal_remove_cleanup(&pam_cleanup_proc, NULL); | |
287 | } | |
288 | ||
289 | /* Start PAM authentication for specified account */ | |
290 | void start_pam(struct passwd *pw) | |
291 | { | |
292 | int pam_retval; | |
293 | ||
294 | debug("Starting up PAM with username \"%.200s\"", pw->pw_name); | |
295 | ||
ad55cd03 | 296 | pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv, &pamh); |
a5c9cd31 | 297 | |
5daf7064 | 298 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 299 | fatal("PAM initialisation failed[%d]: %.200s", |
300 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
5daf7064 | 301 | } |
ae543aaa | 302 | |
a8545c6c | 303 | #ifdef PAM_TTY_KLUDGE |
ae543aaa | 304 | /* |
305 | * Some PAM modules (e.g. pam_time) require a TTY to operate, | |
306 | * and will fail in various stupid ways if they don't get one. | |
307 | * sshd doesn't set the tty until too late in the auth process and may | |
308 | * not even need one (for tty-less connections) | |
309 | * Kludge: Set a fake PAM_TTY | |
310 | */ | |
ad55cd03 | 311 | pam_retval = pam_set_item(pamh, PAM_TTY, "ssh"); |
cbd7492e | 312 | if (pam_retval != PAM_SUCCESS) { |
ebd782f7 | 313 | fatal("PAM set tty failed[%d]: %.200s", |
314 | pam_retval, PAM_STRERROR(pamh, pam_retval)); | |
cbd7492e | 315 | } |
a8545c6c | 316 | #endif /* PAM_TTY_KLUDGE */ |
cbd7492e | 317 | |
a5c9cd31 | 318 | fatal_add_cleanup(&pam_cleanup_proc, NULL); |
319 | } | |
320 | ||
321 | /* Return list of PAM enviornment strings */ | |
322 | char **fetch_pam_environment(void) | |
323 | { | |
2b763e31 | 324 | #ifdef HAVE_PAM_GETENVLIST |
ad55cd03 | 325 | return(pam_getenvlist(pamh)); |
2b763e31 | 326 | #else /* HAVE_PAM_GETENVLIST */ |
327 | return(NULL); | |
328 | #endif /* HAVE_PAM_GETENVLIST */ | |
a5c9cd31 | 329 | } |
330 | ||
331 | /* Print any messages that have been generated during authentication */ | |
332 | /* or account checking to stderr */ | |
333 | void print_pam_messages(void) | |
334 | { | |
5daf7064 | 335 | if (pam_msg != NULL) |
264dce47 | 336 | fputs(pam_msg, stderr); |
5daf7064 | 337 | } |
338 | ||
339 | /* Append a message to the PAM message buffer */ | |
340 | void pam_msg_cat(const char *msg) | |
341 | { | |
342 | char *p; | |
343 | size_t new_msg_len; | |
344 | size_t pam_msg_len; | |
345 | ||
346 | new_msg_len = strlen(msg); | |
347 | ||
348 | if (pam_msg) { | |
349 | pam_msg_len = strlen(pam_msg); | |
350 | pam_msg = xrealloc(pam_msg, new_msg_len + pam_msg_len + 2); | |
351 | p = pam_msg + pam_msg_len; | |
352 | } else { | |
353 | pam_msg = p = xmalloc(new_msg_len + 2); | |
354 | } | |
355 | ||
356 | memcpy(p, msg, new_msg_len); | |
357 | p[new_msg_len] = '\n'; | |
358 | p[new_msg_len + 1] = '\0'; | |
a5c9cd31 | 359 | } |
360 | ||
361 | #endif /* USE_PAM */ |