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.
34 #define NEW_AUTHTOK_MSG \
35 "Warning: Your password has expired, please change it now"
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);
41 void pam_msg_cat(const char *msg);
43 /* module-local variables */
44 static struct pam_conv conv = {
48 static pam_handle_t *pamh = NULL;
49 static const char *pampasswd = NULL;
50 static char *pam_msg = NULL;
52 /* states for pamconv() */
53 enum { INITIAL_LOGIN, OTHER } pamstate = INITIAL_LOGIN;
54 /* remember whether pam_acct_mgmt() returned PAM_NEWAUTHTOK_REQD */
55 static int password_change_required = 0;
56 /* remember whether the last pam_authenticate() succeeded or not */
57 static int was_authenticated = 0;
59 /* accessor which allows us to switch conversation structs according to
60 * the authentication method being used */
61 void pam_set_conv(struct pam_conv *conv)
63 pam_set_item(pamh, PAM_CONV, conv);
66 /* start an authentication run */
67 int do_pam_authenticate(int flags)
69 int retval = pam_authenticate(pamh, flags);
70 was_authenticated = (retval == PAM_SUCCESS);
75 * PAM conversation function.
76 * There are two states this can run in.
78 * INITIAL_LOGIN mode simply feeds the password from the client into
79 * PAM in response to PAM_PROMPT_ECHO_OFF, and collects output
80 * messages with pam_msg_cat(). This is used during initial
81 * authentication to bypass the normal PAM password prompt.
83 * OTHER mode handles PAM_PROMPT_ECHO_OFF with read_passphrase(prompt, 1)
84 * and outputs messages to stderr. This mode is used if pam_chauthtok()
85 * is called to update expired passwords.
87 static int pamconv(int num_msg, const struct pam_message **msg,
88 struct pam_response **resp, void *appdata_ptr)
90 struct pam_response *reply;
94 /* PAM will free this later */
95 reply = malloc(num_msg * sizeof(*reply));
99 for (count = 0; count < num_msg; count++) {
100 switch(PAM_MSG_MEMBER(msg, count, msg_style)) {
101 case PAM_PROMPT_ECHO_ON:
102 if (pamstate == INITIAL_LOGIN) {
106 fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
107 fgets(buf, sizeof(buf), stdin);
108 reply[count].resp = xstrdup(buf);
109 reply[count].resp_retcode = PAM_SUCCESS;
112 case PAM_PROMPT_ECHO_OFF:
113 if (pamstate == INITIAL_LOGIN) {
114 if (pampasswd == NULL) {
118 reply[count].resp = xstrdup(pampasswd);
121 xstrdup(read_passphrase(PAM_MSG_MEMBER(msg, count, msg), 1));
123 reply[count].resp_retcode = PAM_SUCCESS;
127 if ((*msg)[count].msg != NULL) {
128 if (pamstate == INITIAL_LOGIN)
129 pam_msg_cat(PAM_MSG_MEMBER(msg, count, msg));
131 fputs(PAM_MSG_MEMBER(msg, count, msg), stderr);
135 reply[count].resp = xstrdup("");
136 reply[count].resp_retcode = PAM_SUCCESS;
149 /* Called at exit to cleanly shutdown PAM */
150 void pam_cleanup_proc(void *context)
156 pam_retval = pam_close_session(pamh, 0);
157 if (pam_retval != PAM_SUCCESS) {
158 log("Cannot close PAM session[%d]: %.200s",
159 pam_retval, PAM_STRERROR(pamh, pam_retval));
162 pam_retval = pam_setcred(pamh, PAM_DELETE_CRED);
163 if (pam_retval != PAM_SUCCESS) {
164 debug("Cannot delete credentials[%d]: %.200s",
165 pam_retval, PAM_STRERROR(pamh, pam_retval));
168 pam_retval = pam_end(pamh, pam_retval);
169 if (pam_retval != PAM_SUCCESS) {
170 log("Cannot release PAM authentication[%d]: %.200s",
171 pam_retval, PAM_STRERROR(pamh, pam_retval));
176 /* Attempt password authentation using PAM */
177 int auth_pam_password(struct passwd *pw, const char *password)
179 extern ServerOptions options;
184 /* deny if no user. */
187 if (pw->pw_uid == 0 && options.permit_root_login == 2)
189 if (*password == '\0' && options.permit_empty_passwd == 0)
192 pampasswd = password;
194 pamstate = INITIAL_LOGIN;
195 pam_retval = do_pam_authenticate(0);
196 if (pam_retval == PAM_SUCCESS) {
197 debug("PAM Password authentication accepted for user \"%.100s\"",
201 debug("PAM Password authentication for \"%.100s\" failed[%d]: %s",
202 pw->pw_name, pam_retval, PAM_STRERROR(pamh, pam_retval));
207 /* Do account management using PAM */
208 int do_pam_account(char *username, char *remote_user)
212 debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname());
213 pam_retval = pam_set_item(pamh, PAM_RHOST,
214 get_canonical_hostname());
215 if (pam_retval != PAM_SUCCESS) {
216 fatal("PAM set rhost failed[%d]: %.200s",
217 pam_retval, PAM_STRERROR(pamh, pam_retval));
220 if (remote_user != NULL) {
221 debug("PAM setting ruser to \"%.200s\"", remote_user);
222 pam_retval = pam_set_item(pamh, PAM_RUSER, remote_user);
223 if (pam_retval != PAM_SUCCESS) {
224 fatal("PAM set ruser failed[%d]: %.200s",
225 pam_retval, PAM_STRERROR(pamh, pam_retval));
229 pam_retval = pam_acct_mgmt(pamh, 0);
230 switch (pam_retval) {
232 /* This is what we want */
234 case PAM_NEW_AUTHTOK_REQD:
235 pam_msg_cat(NEW_AUTHTOK_MSG);
236 /* flag that password change is necessary */
237 password_change_required = 1;
240 log("PAM rejected by account configuration[%d]: %.200s",
241 pam_retval, PAM_STRERROR(pamh, pam_retval));
248 /* Do PAM-specific session initialisation */
249 void do_pam_session(char *username, const char *ttyname)
253 if (ttyname != NULL) {
254 debug("PAM setting tty to \"%.200s\"", ttyname);
255 pam_retval = pam_set_item(pamh, PAM_TTY, ttyname);
256 if (pam_retval != PAM_SUCCESS) {
257 fatal("PAM set tty failed[%d]: %.200s",
258 pam_retval, PAM_STRERROR(pamh, pam_retval));
262 pam_retval = pam_open_session(pamh, 0);
263 if (pam_retval != PAM_SUCCESS) {
264 fatal("PAM session setup failed[%d]: %.200s",
265 pam_retval, PAM_STRERROR(pamh, pam_retval));
269 /* Set PAM credentials */
270 void do_pam_setcred(void)
274 debug("PAM establishing creds");
275 pam_retval = pam_setcred(pamh, PAM_ESTABLISH_CRED);
276 if (pam_retval != PAM_SUCCESS) {
277 if(was_authenticated) {
278 fatal("PAM setcred failed[%d]: %.200s",
279 pam_retval, PAM_STRERROR(pamh, pam_retval));
281 debug("PAM setcred failed[%d]: %.200s",
282 pam_retval, PAM_STRERROR(pamh, pam_retval));
287 /* accessor function for file scope static variable */
288 int pam_password_change_required(void)
290 return password_change_required;
294 * Have user change authentication token if pam_acct_mgmt() indicated
295 * it was expired. This needs to be called after an interactive
296 * session is established and the user's pty is connected to
297 * stdin/stout/stderr.
299 void do_pam_chauthtok(void)
303 if (password_change_required) {
306 * XXX: should we really loop forever?
309 pam_retval = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
310 if (pam_retval != PAM_SUCCESS) {
311 log("PAM pam_chauthtok failed[%d]: %.200s",
312 pam_retval, PAM_STRERROR(pamh, pam_retval));
314 } while (pam_retval != PAM_SUCCESS);
318 /* Cleanly shutdown PAM */
319 void finish_pam(void)
321 pam_cleanup_proc(NULL);
322 fatal_remove_cleanup(&pam_cleanup_proc, NULL);
325 /* Start PAM authentication for specified account */
326 void start_pam(struct passwd *pw)
330 debug("Starting up PAM with username \"%.200s\"", pw->pw_name);
332 pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv, &pamh);
334 if (pam_retval != PAM_SUCCESS) {
335 fatal("PAM initialisation failed[%d]: %.200s",
336 pam_retval, PAM_STRERROR(pamh, pam_retval));
339 #ifdef PAM_TTY_KLUDGE
341 * Some PAM modules (e.g. pam_time) require a TTY to operate,
342 * and will fail in various stupid ways if they don't get one.
343 * sshd doesn't set the tty until too late in the auth process and may
344 * not even need one (for tty-less connections)
345 * Kludge: Set a fake PAM_TTY
347 pam_retval = pam_set_item(pamh, PAM_TTY, "ssh");
348 if (pam_retval != PAM_SUCCESS) {
349 fatal("PAM set tty failed[%d]: %.200s",
350 pam_retval, PAM_STRERROR(pamh, pam_retval));
352 #endif /* PAM_TTY_KLUDGE */
354 fatal_add_cleanup(&pam_cleanup_proc, NULL);
357 /* Return list of PAM enviornment strings */
358 char **fetch_pam_environment(void)
360 #ifdef HAVE_PAM_GETENVLIST
361 return(pam_getenvlist(pamh));
362 #else /* HAVE_PAM_GETENVLIST */
364 #endif /* HAVE_PAM_GETENVLIST */
367 /* Print any messages that have been generated during authentication */
368 /* or account checking to stderr */
369 void print_pam_messages(void)
372 fputs(pam_msg, stderr);
375 /* Append a message to the PAM message buffer */
376 void pam_msg_cat(const char *msg)
382 new_msg_len = strlen(msg);
385 pam_msg_len = strlen(pam_msg);
386 pam_msg = xrealloc(pam_msg, new_msg_len + pam_msg_len + 2);
387 p = pam_msg + pam_msg_len;
389 pam_msg = p = xmalloc(new_msg_len + 2);
392 memcpy(p, msg, new_msg_len);
393 p[new_msg_len] = '\n';
394 p[new_msg_len + 1] = '\0';