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 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;
59 * PAM conversation function.
60 * There are two states this can run in.
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.
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.
71 static int pamconv(int num_msg, const struct pam_message **msg,
72 struct pam_response **resp, void *appdata_ptr)
74 struct pam_response *reply;
78 /* PAM will free this later */
79 reply = malloc(num_msg * sizeof(*reply));
83 for (count = 0; count < num_msg; count++) {
84 switch ((*msg)[count].msg_style) {
85 case PAM_PROMPT_ECHO_ON:
86 if (pamstate == INITIAL_LOGIN) {
90 fputs((*msg)[count].msg, stderr);
91 fgets(buf, sizeof(buf), stdin);
92 reply[count].resp = xstrdup(buf);
93 reply[count].resp_retcode = PAM_SUCCESS;
96 case PAM_PROMPT_ECHO_OFF:
97 if (pamstate == INITIAL_LOGIN) {
98 if (pampasswd == NULL) {
102 reply[count].resp = xstrdup(pampasswd);
105 xstrdup(read_passphrase((*msg)[count].msg, 1));
107 reply[count].resp_retcode = PAM_SUCCESS;
111 if ((*msg)[count].msg != NULL) {
112 if (pamstate == INITIAL_LOGIN)
113 pam_msg_cat((*msg)[count].msg);
115 fputs((*msg)[count].msg, stderr);
119 reply[count].resp = xstrdup("");
120 reply[count].resp_retcode = PAM_SUCCESS;
133 /* Called at exit to cleanly shutdown PAM */
134 void pam_cleanup_proc(void *context)
140 pam_retval = pam_close_session(pamh, 0);
141 if (pam_retval != PAM_SUCCESS) {
142 log("Cannot close PAM session[%d]: %.200s",
143 pam_retval, PAM_STRERROR(pamh, pam_retval));
146 pam_retval = pam_setcred(pamh, PAM_DELETE_CRED);
147 if (pam_retval != PAM_SUCCESS) {
148 debug("Cannot delete credentials[%d]: %.200s",
149 pam_retval, PAM_STRERROR(pamh, pam_retval));
152 pam_retval = pam_end(pamh, pam_retval);
153 if (pam_retval != PAM_SUCCESS) {
154 log("Cannot release PAM authentication[%d]: %.200s",
155 pam_retval, PAM_STRERROR(pamh, pam_retval));
160 /* Attempt password authentation using PAM */
161 int auth_pam_password(struct passwd *pw, const char *password)
163 extern ServerOptions options;
166 /* deny if no user. */
169 if (pw->pw_uid == 0 && options.permit_root_login == 2)
171 if (*password == '\0' && options.permit_empty_passwd == 0)
174 pampasswd = password;
176 pamstate = INITIAL_LOGIN;
177 pam_retval = pam_authenticate(pamh, 0);
178 if (pam_retval == PAM_SUCCESS) {
179 debug("PAM Password authentication accepted for user \"%.100s\"",
183 debug("PAM Password authentication for \"%.100s\" failed[%d]: %s",
184 pw->pw_name, pam_retval, PAM_STRERROR(pamh, pam_retval));
189 /* Do account management using PAM */
190 int do_pam_account(char *username, char *remote_user)
194 debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname());
195 pam_retval = pam_set_item(pamh, PAM_RHOST,
196 get_canonical_hostname());
197 if (pam_retval != PAM_SUCCESS) {
198 fatal("PAM set rhost failed[%d]: %.200s",
199 pam_retval, PAM_STRERROR(pamh, pam_retval));
202 if (remote_user != NULL) {
203 debug("PAM setting ruser to \"%.200s\"", remote_user);
204 pam_retval = pam_set_item(pamh, PAM_RUSER, remote_user);
205 if (pam_retval != PAM_SUCCESS) {
206 fatal("PAM set ruser failed[%d]: %.200s",
207 pam_retval, PAM_STRERROR(pamh, pam_retval));
211 pam_retval = pam_acct_mgmt(pamh, 0);
212 switch (pam_retval) {
214 /* This is what we want */
216 case PAM_NEW_AUTHTOK_REQD:
217 pam_msg_cat(NEW_AUTHTOK_MSG);
218 /* flag that password change is necessary */
219 password_change_required = 1;
222 log("PAM rejected by account configuration[%d]: %.200s",
223 pam_retval, PAM_STRERROR(pamh, pam_retval));
230 /* Do PAM-specific session initialisation */
231 void do_pam_session(char *username, const char *ttyname)
235 if (ttyname != NULL) {
236 debug("PAM setting tty to \"%.200s\"", ttyname);
237 pam_retval = pam_set_item(pamh, PAM_TTY, ttyname);
238 if (pam_retval != PAM_SUCCESS) {
239 fatal("PAM set tty failed[%d]: %.200s",
240 pam_retval, PAM_STRERROR(pamh, pam_retval));
244 pam_retval = pam_open_session(pamh, 0);
245 if (pam_retval != PAM_SUCCESS) {
246 fatal("PAM session setup failed[%d]: %.200s",
247 pam_retval, PAM_STRERROR(pamh, pam_retval));
251 /* Set PAM credentials */
252 void do_pam_setcred()
256 debug("PAM establishing creds");
257 pam_retval = pam_setcred(pamh, PAM_ESTABLISH_CRED);
258 if (pam_retval != PAM_SUCCESS) {
259 fatal("PAM setcred failed[%d]: %.200s",
260 pam_setcred, PAM_STRERROR(pamh, pam_retval));
265 * Have user change authentication token if pam_acct_mgmt() indicated
266 * it was expired. This needs to be called after an interactive
267 * session is established and the user's pty is connected to
268 * stdin/stout/stderr.
270 void do_pam_chauthtok()
274 if (password_change_required) {
277 * XXX: should we really loop forever?
280 pam_retval = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
281 if (pam_retval != PAM_SUCCESS) {
282 log("PAM pam_chauthtok failed[%d]: %.200s",
283 pam_retval, PAM_STRERROR(pamh, pam_retval));
285 } while (pam_retval != PAM_SUCCESS);
289 /* Cleanly shutdown PAM */
290 void finish_pam(void)
292 pam_cleanup_proc(NULL);
293 fatal_remove_cleanup(&pam_cleanup_proc, NULL);
296 /* Start PAM authentication for specified account */
297 void start_pam(struct passwd *pw)
301 debug("Starting up PAM with username \"%.200s\"", pw->pw_name);
303 pam_retval = pam_start(SSHD_PAM_SERVICE, pw->pw_name, &conv, &pamh);
305 if (pam_retval != PAM_SUCCESS) {
306 fatal("PAM initialisation failed[%d]: %.200s",
307 pam_retval, PAM_STRERROR(pamh, pam_retval));
310 #ifdef PAM_TTY_KLUDGE
312 * Some PAM modules (e.g. pam_time) require a TTY to operate,
313 * and will fail in various stupid ways if they don't get one.
314 * sshd doesn't set the tty until too late in the auth process and may
315 * not even need one (for tty-less connections)
316 * Kludge: Set a fake PAM_TTY
318 pam_retval = pam_set_item(pamh, PAM_TTY, "ssh");
319 if (pam_retval != PAM_SUCCESS) {
320 fatal("PAM set tty failed[%d]: %.200s",
321 pam_retval, PAM_STRERROR(pamh, pam_retval));
323 #endif /* PAM_TTY_KLUDGE */
325 fatal_add_cleanup(&pam_cleanup_proc, NULL);
328 /* Return list of PAM enviornment strings */
329 char **fetch_pam_environment(void)
331 #ifdef HAVE_PAM_GETENVLIST
332 return(pam_getenvlist(pamh));
333 #else /* HAVE_PAM_GETENVLIST */
335 #endif /* HAVE_PAM_GETENVLIST */
338 /* Print any messages that have been generated during authentication */
339 /* or account checking to stderr */
340 void print_pam_messages(void)
343 fputs(pam_msg, stderr);
346 /* Append a message to the PAM message buffer */
347 void pam_msg_cat(const char *msg)
353 new_msg_len = strlen(msg);
356 pam_msg_len = strlen(pam_msg);
357 pam_msg = xrealloc(pam_msg, new_msg_len + pam_msg_len + 2);
358 p = pam_msg + pam_msg_len;
360 pam_msg = p = xmalloc(new_msg_len + 2);
363 memcpy(p, msg, new_msg_len);
364 p[new_msg_len] = '\n';
365 p[new_msg_len + 1] = '\0';