2 * Copyright (c) 2000 Damien Miller. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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.
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.
36 extern char *__progname;
40 #define NEW_AUTHTOK_MSG \
41 "Warning: Your password has expired, please change it now"
43 static int do_pam_conversation(int num_msg, const struct pam_message **msg,
44 struct pam_response **resp, void *appdata_ptr);
46 /* module-local variables */
47 static struct pam_conv conv = {
51 static char *__pam_msg = NULL;
52 static pam_handle_t *__pamh = NULL;
53 static const char *__pampasswd = NULL;
55 /* states for do_pam_conversation() */
56 enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
57 /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_REQD */
58 static int password_change_required = 0;
59 /* remember whether the last pam_authenticate() succeeded or not */
60 static int was_authenticated = 0;
62 /* Remember what has been initialised */
63 static int session_opened = 0;
64 static int creds_set = 0;
66 /* accessor which allows us to switch conversation structs according to
67 * the authentication method being used */
68 void do_pam_set_conv(struct pam_conv *conv)
70 pam_set_item(__pamh, PAM_CONV, conv);
73 /* start an authentication run */
74 int do_pam_authenticate(int flags)
76 int retval = pam_authenticate(__pamh, flags);
77 was_authenticated = (retval == PAM_SUCCESS);
82 * PAM conversation function.
83 * There are two states this can run in.
85 * INITIAL_LOGIN mode simply feeds the password from the client into
86 * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
87 * messages with into __pam_msg. This is used during initial
88 * authentication to bypass the normal PAM password prompt.
90 * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase()
91 * and outputs messages to stderr. This mode is used if pam_chauthtok()
92 * is called to update expired passwords.
94 static int do_pam_conversation(int num_msg, const struct pam_message **msg,
95 struct pam_response **resp, void *appdata_ptr)
97 struct pam_response *reply;
101 /* PAM will free this later */
102 reply = malloc(num_msg * sizeof(*reply));
106 for (count = 0; count < num_msg; count++) {
107 if (pamstate == INITIAL_LOGIN) {
109 * We can't use stdio yet, queue messages for
112 switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
113 case PAM_PROMPT_ECHO_ON:
116 case PAM_PROMPT_ECHO_OFF:
117 if (__pampasswd == NULL) {
121 reply[count].resp = xstrdup(__pampasswd);
122 reply[count].resp_retcode = PAM_SUCCESS;
126 if ((*msg)[count].msg != NULL) {
127 message_cat(&__pam_msg,
128 PAM_MSG_MEMBER(msg, count, msg));
130 reply[count].resp = xstrdup("");
131 reply[count].resp_retcode = PAM_SUCCESS;
139 * stdio is connected, so interact directly
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;
148 case PAM_PROMPT_ECHO_OFF:
150 read_passphrase(PAM_MSG_MEMBER(msg, count,
151 msg), RP_ALLOW_STDIN);
152 reply[count].resp_retcode = PAM_SUCCESS;
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;
174 /* Called at exit to cleanly shutdown PAM */
175 void do_pam_cleanup_proc(void *context)
177 int pam_retval = PAM_SUCCESS;
179 if (__pamh && session_opened) {
180 pam_retval = pam_close_session(__pamh, 0);
181 if (pam_retval != PAM_SUCCESS)
182 log("Cannot close PAM session[%d]: %.200s",
183 pam_retval, PAM_STRERROR(__pamh, pam_retval));
186 if (__pamh && creds_set) {
187 pam_retval = pam_setcred(__pamh, PAM_DELETE_CRED);
188 if (pam_retval != PAM_SUCCESS)
189 debug("Cannot delete credentials[%d]: %.200s",
190 pam_retval, PAM_STRERROR(__pamh, pam_retval));
194 pam_retval = pam_end(__pamh, pam_retval);
195 if (pam_retval != PAM_SUCCESS)
196 log("Cannot release PAM authentication[%d]: %.200s",
197 pam_retval, PAM_STRERROR(__pamh, pam_retval));
201 /* Attempt password authentation using PAM */
202 int auth_pam_password(struct passwd *pw, const char *password)
204 extern ServerOptions options;
207 do_pam_set_conv(&conv);
209 /* deny if no user. */
212 if (pw->pw_uid == 0 && options.permit_root_login == PERMIT_NO_PASSWD)
214 if (*password == '\0' && options.permit_empty_passwd == 0)
217 __pampasswd = password;
219 pamstate = INITIAL_LOGIN;
220 pam_retval = do_pam_authenticate(
221 options.permit_empty_passwd == 0 ? PAM_DISALLOW_NULL_AUTHTOK : 0);
222 if (pam_retval == PAM_SUCCESS) {
223 debug("PAM Password authentication accepted for "
224 "user \"%.100s\"", pw->pw_name);
227 debug("PAM Password authentication for \"%.100s\" "
228 "failed[%d]: %s", pw->pw_name, pam_retval,
229 PAM_STRERROR(__pamh, pam_retval));
234 /* Do account management using PAM */
235 int do_pam_account(char *username, char *remote_user)
239 do_pam_set_conv(&conv);
242 debug("PAM setting ruser to \"%.200s\"", remote_user);
243 pam_retval = pam_set_item(__pamh, PAM_RUSER, remote_user);
244 if (pam_retval != PAM_SUCCESS)
245 fatal("PAM set ruser failed[%d]: %.200s", pam_retval,
246 PAM_STRERROR(__pamh, pam_retval));
249 pam_retval = pam_acct_mgmt(__pamh, 0);
250 switch (pam_retval) {
252 /* This is what we want */
254 case PAM_NEW_AUTHTOK_REQD:
255 message_cat(&__pam_msg, NEW_AUTHTOK_MSG);
256 /* flag that password change is necessary */
257 password_change_required = 1;
260 log("PAM rejected by account configuration[%d]: "
261 "%.200s", pam_retval, PAM_STRERROR(__pamh,
269 /* Do PAM-specific session initialisation */
270 void do_pam_session(char *username, const char *ttyname)
274 do_pam_set_conv(&conv);
276 if (ttyname != NULL) {
277 debug("PAM setting tty to \"%.200s\"", ttyname);
278 pam_retval = pam_set_item(__pamh, PAM_TTY, ttyname);
279 if (pam_retval != PAM_SUCCESS)
280 fatal("PAM set tty failed[%d]: %.200s",
281 pam_retval, PAM_STRERROR(__pamh, pam_retval));
284 pam_retval = pam_open_session(__pamh, 0);
285 if (pam_retval != PAM_SUCCESS)
286 fatal("PAM session setup failed[%d]: %.200s",
287 pam_retval, PAM_STRERROR(__pamh, pam_retval));
292 /* Set PAM credentials */
293 void do_pam_setcred(int init)
297 do_pam_set_conv(&conv);
299 debug("PAM establishing creds");
300 pam_retval = pam_setcred(__pamh,
301 init ? PAM_ESTABLISH_CRED : PAM_REINITIALIZE_CRED);
302 if (pam_retval != PAM_SUCCESS) {
303 if (was_authenticated)
304 fatal("PAM setcred failed[%d]: %.200s",
305 pam_retval, PAM_STRERROR(__pamh, pam_retval));
307 debug("PAM setcred failed[%d]: %.200s",
308 pam_retval, PAM_STRERROR(__pamh, pam_retval));
313 /* accessor function for file scope static variable */
314 int is_pam_password_change_required(void)
316 return password_change_required;
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.
325 void do_pam_chauthtok(void)
329 do_pam_set_conv(&conv);
331 if (password_change_required) {
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));
340 /* Cleanly shutdown PAM */
341 void finish_pam(void)
343 do_pam_cleanup_proc(NULL);
344 fatal_remove_cleanup(&do_pam_cleanup_proc, NULL);
347 /* Start PAM authentication for specified account */
348 void start_pam(const char *user)
351 extern ServerOptions options;
352 extern u_int utmp_len;
355 debug("Starting up PAM with username \"%.200s\"", user);
357 pam_retval = pam_start(SSHD_PAM_SERVICE, user, &conv, &__pamh);
359 if (pam_retval != PAM_SUCCESS)
360 fatal("PAM initialisation failed[%d]: %.200s",
361 pam_retval, PAM_STRERROR(__pamh, pam_retval));
363 rhost = get_remote_name_or_ip(utmp_len, options.reverse_mapping_check);
364 debug("PAM setting rhost to \"%.200s\"", rhost);
366 pam_retval = pam_set_item(__pamh, PAM_RHOST, rhost);
367 if (pam_retval != PAM_SUCCESS)
368 fatal("PAM set rhost failed[%d]: %.200s", pam_retval,
369 PAM_STRERROR(__pamh, pam_retval));
370 #ifdef PAM_TTY_KLUDGE
372 * Some PAM modules (e.g. pam_time) require a TTY to operate,
373 * and will fail in various stupid ways if they don't get one.
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)
376 * Kludge: Set a fake PAM_TTY
378 pam_retval = pam_set_item(__pamh, PAM_TTY, "NODEVssh");
379 if (pam_retval != PAM_SUCCESS)
380 fatal("PAM set tty failed[%d]: %.200s",
381 pam_retval, PAM_STRERROR(__pamh, pam_retval));
382 #endif /* PAM_TTY_KLUDGE */
384 fatal_add_cleanup(&do_pam_cleanup_proc, NULL);
387 /* Return list of PAM enviornment strings */
388 char **fetch_pam_environment(void)
390 #ifdef HAVE_PAM_GETENVLIST
391 return(pam_getenvlist(__pamh));
392 #else /* HAVE_PAM_GETENVLIST */
394 #endif /* HAVE_PAM_GETENVLIST */
397 /* Print any messages that have been generated during authentication */
398 /* or account checking to stderr */
399 void print_pam_messages(void)
401 if (__pam_msg != NULL)
402 fputs(__pam_msg, stderr);
405 /* Append a message to buffer */
406 void message_cat(char **p, const char *a)
414 size_t len = strlen(*p);
416 *p = xrealloc(*p, new_len + len + 2);
419 *p = cp = xmalloc(new_len + 2);
421 memcpy(cp, a, new_len);
423 cp[new_len + 1] = '\0';