blob: d3f400bc30346d934ff3899e925dbbb2fdeac1ac [file] [log] [blame]
Damien Miller4f9f42a2003-05-10 19:28:02 +10001/*-
2 * Copyright (c) 2002 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * NAI Labs, the Security Research Division of Network Associates, Inc.
7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
8 * DARPA CHATS research program.
Damien Millere69f18c2000-06-12 16:38:54 +10009 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
Damien Millere69f18c2000-06-12 16:38:54 +100018 *
Damien Miller4f9f42a2003-05-10 19:28:02 +100019 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
Damien Millere72b7af1999-12-30 15:08:44 +110030 */
Damien Miller26314f62004-06-01 11:28:20 +100031/*
32 * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
33 * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
34 *
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies.
38 *
39 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
40 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
41 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
42 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
43 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
44 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
45 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
46 */
Damien Millere72b7af1999-12-30 15:08:44 +110047
Damien Miller5ef4b0f2016-01-27 17:45:56 +110048/* Based on FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des */
49
Damien Millere72b7af1999-12-30 15:08:44 +110050#include "includes.h"
Damien Miller6645e7a2006-03-15 14:42:54 +110051
52#include <sys/types.h>
53#include <sys/stat.h>
54#include <sys/wait.h>
Darren Tucker341dae52006-07-13 08:45:14 +100055
56#include <errno.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110057#include <signal.h>
Damien Millerded319c2006-09-01 15:38:36 +100058#include <stdarg.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100059#include <string.h>
60#include <unistd.h>
Damien Millere72b7af1999-12-30 15:08:44 +110061
62#ifdef USE_PAM
Damien Miller0f47c532004-01-02 18:01:30 +110063#if defined(HAVE_SECURITY_PAM_APPL_H)
Damien Miller4f9f42a2003-05-10 19:28:02 +100064#include <security/pam_appl.h>
Damien Miller0f47c532004-01-02 18:01:30 +110065#elif defined (HAVE_PAM_PAM_APPL_H)
66#include <pam/pam_appl.h>
67#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +100068
Damien Miller8bd81e12016-08-16 13:30:56 +100069#if !defined(SSHD_PAM_SERVICE)
70extern char *__progname;
71# define SSHD_PAM_SERVICE __progname
72#endif
73
Darren Tuckerf08bdb52005-05-26 19:59:48 +100074/* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */
75#ifdef PAM_SUN_CODEBASE
Darren Tucker39c0cec2016-05-20 10:01:58 +100076# define sshpam_const /* Solaris, HP-UX, SunOS */
Darren Tuckerf08bdb52005-05-26 19:59:48 +100077#else
Darren Tucker39c0cec2016-05-20 10:01:58 +100078# define sshpam_const const /* LinuxPAM, OpenPAM, AIX */
Darren Tuckerf08bdb52005-05-26 19:59:48 +100079#endif
80
Damien Miller2ab323e2006-08-05 12:43:32 +100081/* Ambiguity in spec: is it an array of pointers or a pointer to an array? */
82#ifdef PAM_SUN_CODEBASE
83# define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member)
84#else
85# define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member)
86#endif
87
Damien Miller75bb6642006-08-05 14:07:20 +100088#include "xmalloc.h"
Damien Miller120a1ec2018-07-10 19:39:52 +100089#include "sshbuf.h"
90#include "ssherr.h"
Damien Miller75bb6642006-08-05 14:07:20 +100091#include "hostfile.h"
Kevin Stevese683e762002-04-04 19:02:28 +000092#include "auth.h"
Damien Miller63dc3e92001-02-07 12:58:33 +110093#include "auth-pam.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000094#include "canohost.h"
Damien Miller4f9f42a2003-05-10 19:28:02 +100095#include "log.h"
Damien Miller4f9f42a2003-05-10 19:28:02 +100096#include "msg.h"
97#include "packet.h"
Darren Tuckerb6db1722004-05-13 17:29:35 +100098#include "misc.h"
Damien Miller4f9f42a2003-05-10 19:28:02 +100099#include "servconf.h"
100#include "ssh2.h"
Damien Miller1f499fd2003-08-25 13:08:49 +1000101#include "auth-options.h"
Damien Miller75bb6642006-08-05 14:07:20 +1000102#ifdef GSSAPI
103#include "ssh-gss.h"
104#endif
105#include "monitor_wrap.h"
Damien Millere72b7af1999-12-30 15:08:44 +1100106
Damien Miller4e448a32003-05-14 15:11:48 +1000107extern ServerOptions options;
Damien Miller120a1ec2018-07-10 19:39:52 +1000108extern struct sshbuf *loginmsg;
Darren Tucker2a9bf4b2004-04-18 11:00:26 +1000109extern u_int utmp_len;
Damien Miller4e448a32003-05-14 15:11:48 +1000110
Darren Tucker328118a2005-05-25 16:18:09 +1000111/* so we don't silently change behaviour */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000112#ifdef USE_POSIX_THREADS
Darren Tucker328118a2005-05-25 16:18:09 +1000113# error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
114#endif
115
116/*
117 * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
118 * and generally a bad idea. Use at own risk and do not expect support if
119 * this breaks.
120 */
121#ifdef UNSUPPORTED_POSIX_THREADS_HACK
Damien Miller4f9f42a2003-05-10 19:28:02 +1000122#include <pthread.h>
123/*
Damien Millera8e06ce2003-11-21 23:48:55 +1100124 * Avoid namespace clash when *not* using pthreads for systems *with*
125 * pthreads, which unconditionally define pthread_t via sys/types.h
Damien Miller4f9f42a2003-05-10 19:28:02 +1000126 * (e.g. Linux)
127 */
Damien Millera8e06ce2003-11-21 23:48:55 +1100128typedef pthread_t sp_pthread_t;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000129#else
Darren Tucker1b27c8f2004-01-13 22:35:58 +1100130typedef pid_t sp_pthread_t;
Damien Miller48f54b92018-09-13 12:13:50 +1000131#define pthread_exit fake_pthread_exit
132#define pthread_create fake_pthread_create
133#define pthread_cancel fake_pthread_cancel
134#define pthread_join fake_pthread_join
Darren Tucker1b27c8f2004-01-13 22:35:58 +1100135#endif
136
137struct pam_ctxt {
138 sp_pthread_t pam_thread;
139 int pam_psock;
140 int pam_csock;
141 int pam_done;
142};
143
144static void sshpam_free_ctx(void *);
145static struct pam_ctxt *cleanup_ctxt;
146
Darren Tucker328118a2005-05-25 16:18:09 +1000147#ifndef UNSUPPORTED_POSIX_THREADS_HACK
Damien Miller4f9f42a2003-05-10 19:28:02 +1000148/*
149 * Simulate threads with processes.
150 */
Kevin Steves63007d42002-07-21 17:57:01 +0000151
Darren Tucker749bc952004-01-14 22:14:04 +1100152static int sshpam_thread_status = -1;
153static mysig_t sshpam_oldsig;
154
Damien Miller94cf4c82005-07-17 17:04:47 +1000155static void
Darren Tucker749bc952004-01-14 22:14:04 +1100156sshpam_sigchld_handler(int sig)
157{
Darren Tuckerb53355e2004-05-24 11:55:36 +1000158 signal(SIGCHLD, SIG_DFL);
Darren Tucker7ae09622004-01-14 23:07:56 +1100159 if (cleanup_ctxt == NULL)
160 return; /* handler called after PAM cleanup, shouldn't happen */
Darren Tuckerb53355e2004-05-24 11:55:36 +1000161 if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
Damien Miller37294fb2005-07-17 17:18:49 +1000162 <= 0) {
Darren Tuckerb53355e2004-05-24 11:55:36 +1000163 /* PAM thread has not exitted, privsep slave must have */
164 kill(cleanup_ctxt->pam_thread, SIGTERM);
Damien Miller10358ab2016-07-22 14:06:36 +1000165 while (waitpid(cleanup_ctxt->pam_thread,
166 &sshpam_thread_status, 0) == -1) {
167 if (errno == EINTR)
168 continue;
169 return;
170 }
Darren Tuckerb53355e2004-05-24 11:55:36 +1000171 }
Darren Tucker749bc952004-01-14 22:14:04 +1100172 if (WIFSIGNALED(sshpam_thread_status) &&
173 WTERMSIG(sshpam_thread_status) == SIGTERM)
174 return; /* terminated by pthread_cancel */
175 if (!WIFEXITED(sshpam_thread_status))
Darren Tucker57d4ca92007-08-10 14:32:34 +1000176 sigdie("PAM: authentication thread exited unexpectedly");
Darren Tucker749bc952004-01-14 22:14:04 +1100177 if (WEXITSTATUS(sshpam_thread_status) != 0)
Darren Tucker57d4ca92007-08-10 14:32:34 +1000178 sigdie("PAM: authentication thread exited uncleanly");
Darren Tucker749bc952004-01-14 22:14:04 +1100179}
180
Damien Millerb8fe89c2006-07-24 14:51:00 +1000181/* ARGSUSED */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000182static void
Damien Millerb8fe89c2006-07-24 14:51:00 +1000183pthread_exit(void *value)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000184{
185 _exit(0);
186}
Damien Miller2f6a0ad2000-05-31 11:20:11 +1000187
Damien Millerb8fe89c2006-07-24 14:51:00 +1000188/* ARGSUSED */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000189static int
Damien Millerb8fe89c2006-07-24 14:51:00 +1000190pthread_create(sp_pthread_t *thread, const void *attr,
Damien Miller4f9f42a2003-05-10 19:28:02 +1000191 void *(*thread_start)(void *), void *arg)
192{
193 pid_t pid;
Darren Tucker4f1adad2005-07-16 11:33:06 +1000194 struct pam_ctxt *ctx = arg;
Damien Millere72b7af1999-12-30 15:08:44 +1100195
Darren Tuckerb9b60212004-03-04 20:03:54 +1100196 sshpam_thread_status = -1;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000197 switch ((pid = fork())) {
198 case -1:
199 error("fork(): %s", strerror(errno));
Darren Tuckerd220b672019-06-07 14:26:54 +1000200 return errno;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000201 case 0:
Darren Tucker4f1adad2005-07-16 11:33:06 +1000202 close(ctx->pam_psock);
203 ctx->pam_psock = -1;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000204 thread_start(arg);
205 _exit(1);
206 default:
207 *thread = pid;
Darren Tucker4f1adad2005-07-16 11:33:06 +1000208 close(ctx->pam_csock);
209 ctx->pam_csock = -1;
Darren Tucker749bc952004-01-14 22:14:04 +1100210 sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000211 return (0);
212 }
213}
Damien Millere72b7af1999-12-30 15:08:44 +1100214
Damien Miller4f9f42a2003-05-10 19:28:02 +1000215static int
216pthread_cancel(sp_pthread_t thread)
217{
Darren Tucker7ae09622004-01-14 23:07:56 +1100218 signal(SIGCHLD, sshpam_oldsig);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000219 return (kill(thread, SIGTERM));
220}
221
Damien Millerb8fe89c2006-07-24 14:51:00 +1000222/* ARGSUSED */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000223static int
Damien Millerb8fe89c2006-07-24 14:51:00 +1000224pthread_join(sp_pthread_t thread, void **value)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000225{
226 int status;
227
Darren Tucker749bc952004-01-14 22:14:04 +1100228 if (sshpam_thread_status != -1)
229 return (sshpam_thread_status);
230 signal(SIGCHLD, sshpam_oldsig);
Damien Miller10358ab2016-07-22 14:06:36 +1000231 while (waitpid(thread, &status, 0) == -1) {
232 if (errno == EINTR)
233 continue;
234 fatal("%s: waitpid: %s", __func__, strerror(errno));
235 }
Damien Miller4f9f42a2003-05-10 19:28:02 +1000236 return (status);
237}
238#endif
239
240
Damien Miller5c3a5582003-09-23 22:12:38 +1000241static pam_handle_t *sshpam_handle = NULL;
242static int sshpam_err = 0;
243static int sshpam_authenticated = 0;
Damien Miller5c3a5582003-09-23 22:12:38 +1000244static int sshpam_session_open = 0;
245static int sshpam_cred_established = 0;
Darren Tucker07705c72003-12-18 15:34:31 +1100246static int sshpam_account_status = -1;
Darren Tucker01558b72016-07-18 09:33:25 +1000247static int sshpam_maxtries_reached = 0;
Damien Millerc756e9b2003-11-17 21:41:42 +1100248static char **sshpam_env = NULL;
Darren Tucker17addf02004-03-30 20:57:57 +1000249static Authctxt *sshpam_authctxt = NULL;
Darren Tucker450a1582004-05-30 20:43:59 +1000250static const char *sshpam_password = NULL;
Damien Miller3f0786b2019-01-20 10:22:18 +1100251static char *sshpam_rhost = NULL;
252static char *sshpam_laddr = NULL;
253static char *sshpam_conninfo = NULL;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000254
Damien Millerc756e9b2003-11-17 21:41:42 +1100255/* Some PAM implementations don't implement this */
256#ifndef HAVE_PAM_GETENVLIST
257static char **
258pam_getenvlist(pam_handle_t *pamh)
259{
260 /*
Darren Tuckerfc0340f2019-06-08 00:10:59 +1000261 * XXX - If necessary, we can still support environment passing
Damien Millerc756e9b2003-11-17 21:41:42 +1100262 * for platforms without pam_getenvlist by searching for known
263 * env vars (e.g. KRB5CCNAME) from the PAM environment.
264 */
265 return NULL;
266}
267#endif
268
Darren Tucker606077e2019-05-17 13:14:12 +1000269#ifndef HAVE_PAM_PUTENV
270static int
271pam_putenv(pam_handle_t *pamh, const char *name_value)
272{
273 return PAM_SUCCESS;
274}
275#endif /* HAVE_PAM_PUTENV */
276
Darren Tucker21dd0892004-08-16 23:12:05 +1000277/*
278 * Some platforms, notably Solaris, do not enforce password complexity
279 * rules during pam_chauthtok() if the real uid of the calling process
280 * is 0, on the assumption that it's being called by "passwd" run by root.
281 * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
282 * the right thing.
283 */
284#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
285static int
286sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
287{
288 int result;
289
290 if (sshpam_authctxt == NULL)
291 fatal("PAM: sshpam_authctxt not initialized");
292 if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
293 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
294 result = pam_chauthtok(pamh, flags);
295 if (setreuid(0, -1) == -1)
296 fatal("%s: setreuid failed: %s", __func__, strerror(errno));
297 return result;
298}
299# define pam_chauthtok(a,b) (sshpam_chauthtok_ruid((a), (b)))
300#endif
301
Darren Tucker07705c72003-12-18 15:34:31 +1100302void
Darren Tucker17db1c42004-06-19 12:54:38 +1000303sshpam_password_change_required(int reqd)
Darren Tucker07705c72003-12-18 15:34:31 +1100304{
Darren Tucker13ef4cf2018-03-03 16:21:20 +1100305 extern struct sshauthopt *auth_opts;
306 static int saved_port, saved_agent, saved_x11;
307
Darren Tuckera8df9242004-01-15 00:15:07 +1100308 debug3("%s %d", __func__, reqd);
Darren Tucker17addf02004-03-30 20:57:57 +1000309 if (sshpam_authctxt == NULL)
Darren Tuckerdbf7a742004-03-08 23:04:06 +1100310 fatal("%s: PAM authctxt not initialized", __func__);
Darren Tucker17addf02004-03-30 20:57:57 +1000311 sshpam_authctxt->force_pwchange = reqd;
Darren Tucker07705c72003-12-18 15:34:31 +1100312 if (reqd) {
Darren Tucker13ef4cf2018-03-03 16:21:20 +1100313 saved_port = auth_opts->permit_port_forwarding_flag;
314 saved_agent = auth_opts->permit_agent_forwarding_flag;
315 saved_x11 = auth_opts->permit_x11_forwarding_flag;
316 auth_opts->permit_port_forwarding_flag = 0;
317 auth_opts->permit_agent_forwarding_flag = 0;
318 auth_opts->permit_x11_forwarding_flag = 0;
Darren Tucker07705c72003-12-18 15:34:31 +1100319 } else {
Darren Tucker13ef4cf2018-03-03 16:21:20 +1100320 if (saved_port)
321 auth_opts->permit_port_forwarding_flag = saved_port;
322 if (saved_agent)
323 auth_opts->permit_agent_forwarding_flag = saved_agent;
324 if (saved_x11)
325 auth_opts->permit_x11_forwarding_flag = saved_x11;
Darren Tucker07705c72003-12-18 15:34:31 +1100326 }
327}
Darren Tucker1921ed92004-02-10 13:23:28 +1100328
Damien Millerc756e9b2003-11-17 21:41:42 +1100329/* Import regular and PAM environment from subprocess */
330static void
Damien Miller120a1ec2018-07-10 19:39:52 +1000331import_environments(struct sshbuf *b)
Damien Millerc756e9b2003-11-17 21:41:42 +1100332{
333 char *env;
Damien Miller120a1ec2018-07-10 19:39:52 +1000334 u_int n, i, num_env;
335 int r;
Damien Millerc756e9b2003-11-17 21:41:42 +1100336
Darren Tuckera8df9242004-01-15 00:15:07 +1100337 debug3("PAM: %s entering", __func__);
338
Darren Tucker328118a2005-05-25 16:18:09 +1000339#ifndef UNSUPPORTED_POSIX_THREADS_HACK
Darren Tucker07705c72003-12-18 15:34:31 +1100340 /* Import variables set by do_pam_account */
Damien Miller120a1ec2018-07-10 19:39:52 +1000341 if ((r = sshbuf_get_u32(b, &n)) != 0)
342 fatal("%s: buffer error: %s", __func__, ssh_err(r));
343 if (n > INT_MAX)
344 fatal("%s: invalid PAM account status %u", __func__, n);
345 sshpam_account_status = (int)n;
346 if ((r = sshbuf_get_u32(b, &n)) != 0)
347 fatal("%s: buffer error: %s", __func__, ssh_err(r));
348 sshpam_password_change_required(n != 0);
Darren Tucker07705c72003-12-18 15:34:31 +1100349
Damien Millerc756e9b2003-11-17 21:41:42 +1100350 /* Import environment from subprocess */
Damien Miller120a1ec2018-07-10 19:39:52 +1000351 if ((r = sshbuf_get_u32(b, &num_env)) != 0)
352 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Darren Tuckerd8093e42006-05-04 16:24:34 +1000353 if (num_env > 1024)
354 fatal("%s: received %u environment variables, expected <= 1024",
355 __func__, num_env);
356 sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env));
Damien Millerc756e9b2003-11-17 21:41:42 +1100357 debug3("PAM: num env strings %d", num_env);
Damien Miller120a1ec2018-07-10 19:39:52 +1000358 for(i = 0; i < num_env; i++) {
359 if ((r = sshbuf_get_cstring(b, &(sshpam_env[i]), NULL)) != 0)
360 fatal("%s: buffer error: %s", __func__, ssh_err(r));
361 }
Damien Millerc756e9b2003-11-17 21:41:42 +1100362 sshpam_env[num_env] = NULL;
363
364 /* Import PAM environment from subprocess */
Damien Miller120a1ec2018-07-10 19:39:52 +1000365 if ((r = sshbuf_get_u32(b, &num_env)) != 0)
366 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Damien Millerc756e9b2003-11-17 21:41:42 +1100367 debug("PAM: num PAM env strings %d", num_env);
Damien Miller120a1ec2018-07-10 19:39:52 +1000368 for (i = 0; i < num_env; i++) {
369 if ((r = sshbuf_get_cstring(b, &env, NULL)) != 0)
370 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Damien Millerc756e9b2003-11-17 21:41:42 +1100371 /* Errors are not fatal here */
Damien Miller120a1ec2018-07-10 19:39:52 +1000372 if ((r = pam_putenv(sshpam_handle, env)) != PAM_SUCCESS) {
Damien Millerc756e9b2003-11-17 21:41:42 +1100373 error("PAM: pam_putenv: %s",
Damien Miller120a1ec2018-07-10 19:39:52 +1000374 pam_strerror(sshpam_handle, r));
Damien Millerc756e9b2003-11-17 21:41:42 +1100375 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000376 /* XXX leak env? */
Damien Millerc756e9b2003-11-17 21:41:42 +1100377 }
Darren Tucker4b385d42004-03-04 19:54:10 +1100378#endif
Damien Millerc756e9b2003-11-17 21:41:42 +1100379}
380
Damien Miller9d5705a2000-09-16 16:09:27 +1100381/*
Damien Miller4f9f42a2003-05-10 19:28:02 +1000382 * Conversation function for authentication thread.
Damien Miller9d5705a2000-09-16 16:09:27 +1100383 */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000384static int
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000385sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
Damien Miller1f499fd2003-08-25 13:08:49 +1000386 struct pam_response **resp, void *data)
Damien Millere72b7af1999-12-30 15:08:44 +1100387{
Damien Miller120a1ec2018-07-10 19:39:52 +1000388 struct sshbuf *buffer;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000389 struct pam_ctxt *ctxt;
Damien Miller5c3a5582003-09-23 22:12:38 +1000390 struct pam_response *reply;
Damien Miller120a1ec2018-07-10 19:39:52 +1000391 int r, i;
392 u_char status;
Kevin Steves38b050a2002-07-23 00:44:07 +0000393
Darren Tuckerba53b832004-02-17 20:46:59 +1100394 debug3("PAM: %s entering, %d messages", __func__, n);
Damien Miller5c3a5582003-09-23 22:12:38 +1000395 *resp = NULL;
396
Darren Tucker59e06022004-06-30 20:34:31 +1000397 if (data == NULL) {
398 error("PAM: conversation function passed a null context");
399 return (PAM_CONV_ERR);
400 }
Damien Miller4f9f42a2003-05-10 19:28:02 +1000401 ctxt = data;
402 if (n <= 0 || n > PAM_MAX_NUM_MSG)
403 return (PAM_CONV_ERR);
Damien Miller5c3a5582003-09-23 22:12:38 +1000404
Darren Tuckerd8093e42006-05-04 16:24:34 +1000405 if ((reply = calloc(n, sizeof(*reply))) == NULL)
Damien Miller120a1ec2018-07-10 19:39:52 +1000406 return PAM_CONV_ERR;
407 if ((buffer = sshbuf_new()) == NULL) {
408 free(reply);
409 return PAM_CONV_ERR;
410 }
Damien Miller5c3a5582003-09-23 22:12:38 +1000411
Damien Miller4f9f42a2003-05-10 19:28:02 +1000412 for (i = 0; i < n; ++i) {
Damien Miller4f9f42a2003-05-10 19:28:02 +1000413 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
414 case PAM_PROMPT_ECHO_OFF:
Damien Miller4f9f42a2003-05-10 19:28:02 +1000415 case PAM_PROMPT_ECHO_ON:
Damien Miller120a1ec2018-07-10 19:39:52 +1000416 if ((r = sshbuf_put_cstring(buffer,
417 PAM_MSG_MEMBER(msg, i, msg))) != 0)
418 fatal("%s: buffer error: %s",
419 __func__, ssh_err(r));
Damien Millera8e06ce2003-11-21 23:48:55 +1100420 if (ssh_msg_send(ctxt->pam_csock,
Damien Miller120a1ec2018-07-10 19:39:52 +1000421 PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
Damien Miller9bdba702003-11-17 21:27:55 +1100422 goto fail;
Damien Miller120a1ec2018-07-10 19:39:52 +1000423
424 if (ssh_msg_recv(ctxt->pam_csock, buffer) == -1)
Damien Miller9bdba702003-11-17 21:27:55 +1100425 goto fail;
Damien Miller120a1ec2018-07-10 19:39:52 +1000426 if ((r = sshbuf_get_u8(buffer, &status)) != 0)
427 fatal("%s: buffer error: %s",
428 __func__, ssh_err(r));
429 if (status != PAM_AUTHTOK)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000430 goto fail;
Damien Miller120a1ec2018-07-10 19:39:52 +1000431 if ((r = sshbuf_get_cstring(buffer,
432 &reply[i].resp, NULL)) != 0)
433 fatal("%s: buffer error: %s",
434 __func__, ssh_err(r));
Damien Miller4f9f42a2003-05-10 19:28:02 +1000435 break;
436 case PAM_ERROR_MSG:
Damien Miller4f9f42a2003-05-10 19:28:02 +1000437 case PAM_TEXT_INFO:
Damien Miller120a1ec2018-07-10 19:39:52 +1000438 if ((r = sshbuf_put_cstring(buffer,
439 PAM_MSG_MEMBER(msg, i, msg))) != 0)
440 fatal("%s: buffer error: %s",
441 __func__, ssh_err(r));
Damien Millera8e06ce2003-11-21 23:48:55 +1100442 if (ssh_msg_send(ctxt->pam_csock,
Damien Miller120a1ec2018-07-10 19:39:52 +1000443 PAM_MSG_MEMBER(msg, i, msg_style), buffer) == -1)
Damien Miller9bdba702003-11-17 21:27:55 +1100444 goto fail;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000445 break;
446 default:
447 goto fail;
448 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000449 sshbuf_reset(buffer);
Kevin Steves38b050a2002-07-23 00:44:07 +0000450 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000451 sshbuf_free(buffer);
Damien Miller5c3a5582003-09-23 22:12:38 +1000452 *resp = reply;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000453 return (PAM_SUCCESS);
Damien Miller5c3a5582003-09-23 22:12:38 +1000454
Damien Miller4f9f42a2003-05-10 19:28:02 +1000455 fail:
Damien Miller5c3a5582003-09-23 22:12:38 +1000456 for(i = 0; i < n; i++) {
Darren Tuckerf60845f2013-06-02 08:07:31 +1000457 free(reply[i].resp);
Damien Miller5c3a5582003-09-23 22:12:38 +1000458 }
Darren Tuckerf60845f2013-06-02 08:07:31 +1000459 free(reply);
Damien Miller120a1ec2018-07-10 19:39:52 +1000460 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000461 return (PAM_CONV_ERR);
Kevin Steves38b050a2002-07-23 00:44:07 +0000462}
463
Damien Miller4f9f42a2003-05-10 19:28:02 +1000464/*
465 * Authentication thread.
466 */
467static void *
468sshpam_thread(void *ctxtp)
Damien Millere72b7af1999-12-30 15:08:44 +1100469{
Damien Miller4f9f42a2003-05-10 19:28:02 +1000470 struct pam_ctxt *ctxt = ctxtp;
Damien Miller120a1ec2018-07-10 19:39:52 +1000471 struct sshbuf *buffer = NULL;
Damien Millerf4b6f102003-09-02 23:12:06 +1000472 struct pam_conv sshpam_conv;
Damien Miller120a1ec2018-07-10 19:39:52 +1000473 int r, flags = (options.permit_empty_passwd == 0 ?
Darren Tucker1f7e4082004-07-01 14:00:14 +1000474 PAM_DISALLOW_NULL_AUTHTOK : 0);
Darren Tucker328118a2005-05-25 16:18:09 +1000475#ifndef UNSUPPORTED_POSIX_THREADS_HACK
Damien Millerc756e9b2003-11-17 21:41:42 +1100476 extern char **environ;
477 char **env_from_pam;
478 u_int i;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000479 const char *pam_user;
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000480 const char **ptr_pam_user = &pam_user;
Darren Tucker54e1b222006-09-17 11:57:46 +1000481 char *tz = getenv("TZ");
Damien Miller4f9f42a2003-05-10 19:28:02 +1000482
Darren Tucker53f8e782013-12-19 11:31:44 +1100483 sshpam_err = pam_get_item(sshpam_handle, PAM_USER,
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000484 (sshpam_const void **)ptr_pam_user);
Darren Tucker53f8e782013-12-19 11:31:44 +1100485 if (sshpam_err != PAM_SUCCESS)
486 goto auth_fail;
Darren Tucker54e1b222006-09-17 11:57:46 +1000487
Damien Millerc756e9b2003-11-17 21:41:42 +1100488 environ[0] = NULL;
Darren Tucker54e1b222006-09-17 11:57:46 +1000489 if (tz != NULL)
490 if (setenv("TZ", tz, 1) == -1)
491 error("PAM: could not set TZ environment: %s",
492 strerror(errno));
Damien Miller2d2ed3d2004-07-21 20:54:47 +1000493
494 if (sshpam_authctxt != NULL) {
495 setproctitle("%s [pam]",
496 sshpam_authctxt->valid ? pam_user : "unknown");
497 }
Damien Miller4f9f42a2003-05-10 19:28:02 +1000498#endif
499
Damien Millerf4b6f102003-09-02 23:12:06 +1000500 sshpam_conv.conv = sshpam_thread_conv;
501 sshpam_conv.appdata_ptr = ctxt;
502
Darren Tucker17addf02004-03-30 20:57:57 +1000503 if (sshpam_authctxt == NULL)
Darren Tuckerdbf7a742004-03-08 23:04:06 +1100504 fatal("%s: PAM authctxt not initialized", __func__);
505
Damien Miller120a1ec2018-07-10 19:39:52 +1000506 if ((buffer = sshbuf_new()) == NULL)
507 fatal("%s: sshbuf_new failed", __func__);
508
Damien Miller4f9f42a2003-05-10 19:28:02 +1000509 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
510 (const void *)&sshpam_conv);
511 if (sshpam_err != PAM_SUCCESS)
512 goto auth_fail;
Darren Tucker1f7e4082004-07-01 14:00:14 +1000513 sshpam_err = pam_authenticate(sshpam_handle, flags);
Darren Tucker01558b72016-07-18 09:33:25 +1000514 if (sshpam_err == PAM_MAXTRIES)
515 sshpam_set_maxtries_reached(1);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000516 if (sshpam_err != PAM_SUCCESS)
517 goto auth_fail;
Darren Tucker07705c72003-12-18 15:34:31 +1100518
Darren Tucker608ec1f2017-03-29 09:50:54 +1100519 if (!do_pam_account()) {
520 sshpam_err = PAM_ACCT_EXPIRED;
521 goto auth_fail;
522 }
523 if (sshpam_authctxt->force_pwchange) {
524 sshpam_err = pam_chauthtok(sshpam_handle,
525 PAM_CHANGE_EXPIRED_AUTHTOK);
526 if (sshpam_err != PAM_SUCCESS)
Darren Tucker07705c72003-12-18 15:34:31 +1100527 goto auth_fail;
Darren Tucker608ec1f2017-03-29 09:50:54 +1100528 sshpam_password_change_required(0);
Darren Tuckerc376c862003-12-18 16:08:59 +1100529 }
Darren Tucker07705c72003-12-18 15:34:31 +1100530
Damien Miller120a1ec2018-07-10 19:39:52 +1000531 if ((r = sshbuf_put_cstring(buffer, "OK")) != 0)
532 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Damien Millerc756e9b2003-11-17 21:41:42 +1100533
Darren Tucker328118a2005-05-25 16:18:09 +1000534#ifndef UNSUPPORTED_POSIX_THREADS_HACK
Darren Tucker07705c72003-12-18 15:34:31 +1100535 /* Export variables set by do_pam_account */
Damien Miller120a1ec2018-07-10 19:39:52 +1000536 if ((r = sshbuf_put_u32(buffer, sshpam_account_status)) != 0 ||
537 (r = sshbuf_put_u32(buffer, sshpam_authctxt->force_pwchange)) != 0)
538 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Darren Tucker07705c72003-12-18 15:34:31 +1100539
Damien Millerc756e9b2003-11-17 21:41:42 +1100540 /* Export any environment strings set in child */
Damien Miller120a1ec2018-07-10 19:39:52 +1000541 for (i = 0; environ[i] != NULL; i++) {
542 /* Count */
543 if (i > INT_MAX)
Darren Tuckerfc0340f2019-06-08 00:10:59 +1000544 fatal("%s: too many environment strings", __func__);
Damien Miller120a1ec2018-07-10 19:39:52 +1000545 }
546 if ((r = sshbuf_put_u32(buffer, i)) != 0)
547 fatal("%s: buffer error: %s", __func__, ssh_err(r));
548 for (i = 0; environ[i] != NULL; i++) {
549 if ((r = sshbuf_put_cstring(buffer, environ[i])) != 0)
550 fatal("%s: buffer error: %s", __func__, ssh_err(r));
551 }
Damien Millerc756e9b2003-11-17 21:41:42 +1100552 /* Export any environment strings set by PAM in child */
553 env_from_pam = pam_getenvlist(sshpam_handle);
Damien Miller120a1ec2018-07-10 19:39:52 +1000554 for (i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) {
555 /* Count */
556 if (i > INT_MAX)
Darren Tuckerfc0340f2019-06-08 00:10:59 +1000557 fatal("%s: too many PAM environment strings", __func__);
Damien Miller120a1ec2018-07-10 19:39:52 +1000558 }
559 if ((r = sshbuf_put_u32(buffer, i)) != 0)
560 fatal("%s: buffer error: %s", __func__, ssh_err(r));
561 for (i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++) {
562 if ((r = sshbuf_put_cstring(buffer, env_from_pam[i])) != 0)
563 fatal("%s: buffer error: %s", __func__, ssh_err(r));
564 }
Darren Tucker328118a2005-05-25 16:18:09 +1000565#endif /* UNSUPPORTED_POSIX_THREADS_HACK */
Damien Millerc756e9b2003-11-17 21:41:42 +1100566
Damien Miller9bdba702003-11-17 21:27:55 +1100567 /* XXX - can't do much about an error here */
Damien Miller120a1ec2018-07-10 19:39:52 +1000568 ssh_msg_send(ctxt->pam_csock, sshpam_err, buffer);
569 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000570 pthread_exit(NULL);
571
572 auth_fail:
Damien Miller120a1ec2018-07-10 19:39:52 +1000573 if ((r = sshbuf_put_cstring(buffer,
574 pam_strerror(sshpam_handle, sshpam_err))) != 0)
575 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Damien Miller9bdba702003-11-17 21:27:55 +1100576 /* XXX - can't do much about an error here */
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000577 if (sshpam_err == PAM_ACCT_EXPIRED)
Damien Miller120a1ec2018-07-10 19:39:52 +1000578 ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, buffer);
Darren Tucker01558b72016-07-18 09:33:25 +1000579 else if (sshpam_maxtries_reached)
Damien Miller120a1ec2018-07-10 19:39:52 +1000580 ssh_msg_send(ctxt->pam_csock, PAM_MAXTRIES, buffer);
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000581 else
Damien Miller120a1ec2018-07-10 19:39:52 +1000582 ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, buffer);
583 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000584 pthread_exit(NULL);
Damien Miller787b2ec2003-11-21 23:56:47 +1100585
Damien Miller4f9f42a2003-05-10 19:28:02 +1000586 return (NULL); /* Avoid warning for non-pthread case */
Damien Miller2f6a0ad2000-05-31 11:20:11 +1000587}
588
Darren Tucker8846a072003-10-07 11:30:15 +1000589void
590sshpam_thread_cleanup(void)
Damien Miller2f6a0ad2000-05-31 11:20:11 +1000591{
Darren Tucker8846a072003-10-07 11:30:15 +1000592 struct pam_ctxt *ctxt = cleanup_ctxt;
Kevin Stevesef4eea92001-02-05 12:42:17 +0000593
Darren Tuckera8df9242004-01-15 00:15:07 +1100594 debug3("PAM: %s entering", __func__);
Darren Tucker8846a072003-10-07 11:30:15 +1000595 if (ctxt != NULL && ctxt->pam_thread != 0) {
596 pthread_cancel(ctxt->pam_thread);
597 pthread_join(ctxt->pam_thread, NULL);
598 close(ctxt->pam_psock);
599 close(ctxt->pam_csock);
600 memset(ctxt, 0, sizeof(*ctxt));
601 cleanup_ctxt = NULL;
602 }
Damien Miller4f9f42a2003-05-10 19:28:02 +1000603}
Kevin Stevesef4eea92001-02-05 12:42:17 +0000604
Damien Miller4f9f42a2003-05-10 19:28:02 +1000605static int
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000606sshpam_null_conv(int n, sshpam_const struct pam_message **msg,
Damien Miller1f499fd2003-08-25 13:08:49 +1000607 struct pam_response **resp, void *data)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000608{
Darren Tuckerba53b832004-02-17 20:46:59 +1100609 debug3("PAM: %s entering, %d messages", __func__, n);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000610 return (PAM_CONV_ERR);
611}
Damien Miller63dc3e92001-02-07 12:58:33 +1100612
Damien Miller4f9f42a2003-05-10 19:28:02 +1000613static struct pam_conv null_conv = { sshpam_null_conv, NULL };
614
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000615static int
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000616sshpam_store_conv(int n, sshpam_const struct pam_message **msg,
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000617 struct pam_response **resp, void *data)
618{
619 struct pam_response *reply;
Damien Miller120a1ec2018-07-10 19:39:52 +1000620 int r, i;
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000621
622 debug3("PAM: %s called with %d messages", __func__, n);
623 *resp = NULL;
624
625 if (n <= 0 || n > PAM_MAX_NUM_MSG)
626 return (PAM_CONV_ERR);
627
Darren Tuckerd8093e42006-05-04 16:24:34 +1000628 if ((reply = calloc(n, sizeof(*reply))) == NULL)
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000629 return (PAM_CONV_ERR);
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000630
631 for (i = 0; i < n; ++i) {
632 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
633 case PAM_ERROR_MSG:
634 case PAM_TEXT_INFO:
Damien Miller120a1ec2018-07-10 19:39:52 +1000635 if ((r = sshbuf_putf(loginmsg, "%s\n",
636 PAM_MSG_MEMBER(msg, i, msg))) != 0)
637 fatal("%s: buffer error: %s",
638 __func__, ssh_err(r));
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000639 reply[i].resp_retcode = PAM_SUCCESS;
640 break;
641 default:
642 goto fail;
643 }
644 }
645 *resp = reply;
646 return (PAM_SUCCESS);
647
648 fail:
649 for(i = 0; i < n; i++) {
Darren Tuckerf60845f2013-06-02 08:07:31 +1000650 free(reply[i].resp);
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000651 }
Darren Tuckerf60845f2013-06-02 08:07:31 +1000652 free(reply);
Darren Tucker0a7e3c62004-09-11 22:28:01 +1000653 return (PAM_CONV_ERR);
654}
655
656static struct pam_conv store_conv = { sshpam_store_conv, NULL };
657
Darren Tucker8846a072003-10-07 11:30:15 +1000658void
659sshpam_cleanup(void)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000660{
Darren Tucker52358d62008-03-11 22:58:25 +1100661 if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor()))
Damien Miller5c3a5582003-09-23 22:12:38 +1000662 return;
Darren Tucker52358d62008-03-11 22:58:25 +1100663 debug("PAM: cleanup");
Damien Miller4f9f42a2003-05-10 19:28:02 +1000664 pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000665 if (sshpam_session_open) {
Darren Tucker52358d62008-03-11 22:58:25 +1100666 debug("PAM: closing session");
Damien Miller4f9f42a2003-05-10 19:28:02 +1000667 pam_close_session(sshpam_handle, PAM_SILENT);
668 sshpam_session_open = 0;
669 }
Darren Tucker622d5c52009-07-12 22:07:21 +1000670 if (sshpam_cred_established) {
671 debug("PAM: deleting credentials");
672 pam_setcred(sshpam_handle, PAM_DELETE_CRED);
673 sshpam_cred_established = 0;
674 }
Darren Tucker1921ed92004-02-10 13:23:28 +1100675 sshpam_authenticated = 0;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000676 pam_end(sshpam_handle, sshpam_err);
677 sshpam_handle = NULL;
678}
679
680static int
Damien Miller3f0786b2019-01-20 10:22:18 +1100681sshpam_init(struct ssh *ssh, Authctxt *authctxt)
Damien Miller4f9f42a2003-05-10 19:28:02 +1000682{
Damien Miller3f0786b2019-01-20 10:22:18 +1100683 const char *pam_user, *user = authctxt->user;
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000684 const char **ptr_pam_user = &pam_user;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000685
Damien Miller3f0786b2019-01-20 10:22:18 +1100686 if (sshpam_handle == NULL) {
687 if (ssh == NULL) {
688 fatal("%s: called initially with no "
689 "packet context", __func__);
690 }
691 } if (sshpam_handle != NULL) {
Damien Miller4f9f42a2003-05-10 19:28:02 +1000692 /* We already have a PAM context; check if the user matches */
693 sshpam_err = pam_get_item(sshpam_handle,
Darren Tuckerf08bdb52005-05-26 19:59:48 +1000694 PAM_USER, (sshpam_const void **)ptr_pam_user);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000695 if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
696 return (0);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000697 pam_end(sshpam_handle, sshpam_err);
698 sshpam_handle = NULL;
699 }
700 debug("PAM: initializing for \"%s\"", user);
Darren Tuckerc58c2ee2003-09-13 22:02:05 +1000701 sshpam_err =
Darren Tucker77fc29e2004-09-11 23:07:03 +1000702 pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
Darren Tucker17addf02004-03-30 20:57:57 +1000703 sshpam_authctxt = authctxt;
Darren Tuckerdbf7a742004-03-08 23:04:06 +1100704
Damien Miller4f9f42a2003-05-10 19:28:02 +1000705 if (sshpam_err != PAM_SUCCESS) {
706 pam_end(sshpam_handle, sshpam_err);
707 sshpam_handle = NULL;
708 return (-1);
709 }
Damien Miller8a22ffa2018-12-07 15:41:16 +1100710
Damien Miller3f0786b2019-01-20 10:22:18 +1100711 if (ssh != NULL && sshpam_rhost == NULL) {
712 /*
713 * We need to cache these as we don't have packet context
714 * during the kbdint flow.
715 */
716 sshpam_rhost = xstrdup(auth_get_canonical_hostname(ssh,
717 options.use_dns));
718 sshpam_laddr = get_local_ipaddr(
719 ssh_packet_get_connection_in(ssh));
720 xasprintf(&sshpam_conninfo, "SSH_CONNECTION=%.50s %d %.50s %d",
721 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
722 sshpam_laddr, ssh_local_port(ssh));
723 }
724 if (sshpam_rhost != NULL) {
725 debug("PAM: setting PAM_RHOST to \"%s\"", sshpam_rhost);
726 sshpam_err = pam_set_item(sshpam_handle, PAM_RHOST,
727 sshpam_rhost);
728 if (sshpam_err != PAM_SUCCESS) {
729 pam_end(sshpam_handle, sshpam_err);
730 sshpam_handle = NULL;
731 return (-1);
732 }
733 /* Put SSH_CONNECTION in the PAM environment too */
734 pam_putenv(sshpam_handle, sshpam_conninfo);
735 }
Damien Miller8a22ffa2018-12-07 15:41:16 +1100736
Damien Miller25d93422003-05-18 20:45:47 +1000737#ifdef PAM_TTY_KLUDGE
Damien Millera8e06ce2003-11-21 23:48:55 +1100738 /*
739 * Some silly PAM modules (e.g. pam_time) require a TTY to operate.
740 * sshd doesn't set the tty until too late in the auth process and
Damien Miller25d93422003-05-18 20:45:47 +1000741 * may not even set one (for tty-less connections)
Damien Millera8e06ce2003-11-21 23:48:55 +1100742 */
Damien Miller25d93422003-05-18 20:45:47 +1000743 debug("PAM: setting PAM_TTY to \"ssh\"");
744 sshpam_err = pam_set_item(sshpam_handle, PAM_TTY, "ssh");
745 if (sshpam_err != PAM_SUCCESS) {
746 pam_end(sshpam_handle, sshpam_err);
747 sshpam_handle = NULL;
748 return (-1);
749 }
750#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +1000751 return (0);
752}
753
Damien Millere8f47452018-04-06 14:11:44 +1000754static void
755expose_authinfo(const char *caller)
756{
757 char *auth_info;
758
759 /*
760 * Expose authentication information to PAM.
761 * The environment variable is versioned. Please increment the
762 * version suffix if the format of session_info changes.
763 */
764 if (sshpam_authctxt->session_info == NULL)
765 auth_info = xstrdup("");
766 else if ((auth_info = sshbuf_dup_string(
767 sshpam_authctxt->session_info)) == NULL)
768 fatal("%s: sshbuf_dup_string failed", __func__);
769
770 debug2("%s: auth information in SSH_AUTH_INFO_0", caller);
771 do_pam_putenv("SSH_AUTH_INFO_0", auth_info);
772 free(auth_info);
773}
774
Damien Miller4f9f42a2003-05-10 19:28:02 +1000775static void *
776sshpam_init_ctx(Authctxt *authctxt)
777{
778 struct pam_ctxt *ctxt;
Darren Tuckerd220b672019-06-07 14:26:54 +1000779 int result, socks[2];
Damien Miller4f9f42a2003-05-10 19:28:02 +1000780
Darren Tuckera8df9242004-01-15 00:15:07 +1100781 debug3("PAM: %s entering", __func__);
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000782 /*
783 * Refuse to start if we don't have PAM enabled or do_pam_account
784 * has previously failed.
785 */
786 if (!options.use_pam || sshpam_account_status == 0)
Damien Miller4e448a32003-05-14 15:11:48 +1000787 return NULL;
788
Damien Miller4f9f42a2003-05-10 19:28:02 +1000789 /* Initialize PAM */
Damien Miller3f0786b2019-01-20 10:22:18 +1100790 if (sshpam_init(NULL, authctxt) == -1) {
Damien Miller4f9f42a2003-05-10 19:28:02 +1000791 error("PAM: initialization failed");
792 return (NULL);
793 }
794
Damien Millere8f47452018-04-06 14:11:44 +1000795 expose_authinfo(__func__);
Darren Tucker29171e92007-05-20 15:20:08 +1000796 ctxt = xcalloc(1, sizeof *ctxt);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000797
798 /* Start the authentication thread */
799 if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
800 error("PAM: failed create sockets: %s", strerror(errno));
Darren Tuckerf60845f2013-06-02 08:07:31 +1000801 free(ctxt);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000802 return (NULL);
803 }
804 ctxt->pam_psock = socks[0];
805 ctxt->pam_csock = socks[1];
Elliott Hughes1bd4f7f2019-04-25 13:36:27 -0700806 result = pthread_create(&ctxt->pam_thread, NULL, sshpam_thread, ctxt);
807 if (result != 0) {
Damien Miller4f9f42a2003-05-10 19:28:02 +1000808 error("PAM: failed to start authentication thread: %s",
Elliott Hughes1bd4f7f2019-04-25 13:36:27 -0700809 strerror(result));
Damien Miller4f9f42a2003-05-10 19:28:02 +1000810 close(socks[0]);
811 close(socks[1]);
Darren Tuckerf60845f2013-06-02 08:07:31 +1000812 free(ctxt);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000813 return (NULL);
814 }
Darren Tucker8846a072003-10-07 11:30:15 +1000815 cleanup_ctxt = ctxt;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000816 return (ctxt);
817}
818
819static int
820sshpam_query(void *ctx, char **name, char **info,
821 u_int *num, char ***prompts, u_int **echo_on)
822{
Damien Miller120a1ec2018-07-10 19:39:52 +1000823 struct sshbuf *buffer;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000824 struct pam_ctxt *ctxt = ctx;
825 size_t plen;
826 u_char type;
827 char *msg;
Damien Millerdaffc6a2004-10-16 18:52:44 +1000828 size_t len, mlen;
Damien Miller120a1ec2018-07-10 19:39:52 +1000829 int r;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000830
Darren Tuckera8df9242004-01-15 00:15:07 +1100831 debug3("PAM: %s entering", __func__);
Damien Miller120a1ec2018-07-10 19:39:52 +1000832 if ((buffer = sshbuf_new()) == NULL)
833 fatal("%s: sshbuf_new failed", __func__);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000834 *name = xstrdup("");
835 *info = xstrdup("");
836 *prompts = xmalloc(sizeof(char *));
837 **prompts = NULL;
838 plen = 0;
839 *echo_on = xmalloc(sizeof(u_int));
Damien Miller120a1ec2018-07-10 19:39:52 +1000840 while (ssh_msg_recv(ctxt->pam_psock, buffer) == 0) {
841 if ((r = sshbuf_get_u8(buffer, &type)) != 0 ||
842 (r = sshbuf_get_cstring(buffer, &msg, &mlen)) != 0)
843 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Damien Miller4f9f42a2003-05-10 19:28:02 +1000844 switch (type) {
845 case PAM_PROMPT_ECHO_ON:
846 case PAM_PROMPT_ECHO_OFF:
847 *num = 1;
Damien Millerdaffc6a2004-10-16 18:52:44 +1000848 len = plen + mlen + 1;
Darren Tuckerd1680d32015-04-30 09:18:11 +1000849 **prompts = xreallocarray(**prompts, 1, len);
Damien Millerdaffc6a2004-10-16 18:52:44 +1000850 strlcpy(**prompts + plen, msg, len - plen);
851 plen += mlen;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000852 **echo_on = (type == PAM_PROMPT_ECHO_ON);
Darren Tuckerf60845f2013-06-02 08:07:31 +1000853 free(msg);
Damien Millerec0e6242019-09-13 13:14:39 +1000854 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000855 return (0);
856 case PAM_ERROR_MSG:
857 case PAM_TEXT_INFO:
858 /* accumulate messages */
Damien Millerdaffc6a2004-10-16 18:52:44 +1000859 len = plen + mlen + 2;
Darren Tuckerd1680d32015-04-30 09:18:11 +1000860 **prompts = xreallocarray(**prompts, 1, len);
Damien Millerdaffc6a2004-10-16 18:52:44 +1000861 strlcpy(**prompts + plen, msg, len - plen);
862 plen += mlen;
863 strlcat(**prompts + plen, "\n", len - plen);
864 plen++;
Darren Tuckerf60845f2013-06-02 08:07:31 +1000865 free(msg);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000866 break;
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000867 case PAM_ACCT_EXPIRED:
Darren Tucker01558b72016-07-18 09:33:25 +1000868 case PAM_MAXTRIES:
869 if (type == PAM_ACCT_EXPIRED)
870 sshpam_account_status = 0;
871 if (type == PAM_MAXTRIES)
872 sshpam_set_maxtries_reached(1);
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000873 /* FALLTHROUGH */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000874 case PAM_AUTH_ERR:
Darren Tucker2c77b7f2006-05-15 17:22:33 +1000875 debug3("PAM: %s", pam_strerror(sshpam_handle, type));
Darren Tucker7b1e6952005-09-28 22:33:27 +1000876 if (**prompts != NULL && strlen(**prompts) != 0) {
877 *info = **prompts;
878 **prompts = NULL;
879 *num = 0;
880 **echo_on = 0;
881 ctxt->pam_done = -1;
Darren Tuckerf60845f2013-06-02 08:07:31 +1000882 free(msg);
Damien Millerec0e6242019-09-13 13:14:39 +1000883 sshbuf_free(buffer);
Darren Tucker7b1e6952005-09-28 22:33:27 +1000884 return 0;
885 }
886 /* FALLTHROUGH */
887 case PAM_SUCCESS:
Damien Miller4f9f42a2003-05-10 19:28:02 +1000888 if (**prompts != NULL) {
889 /* drain any accumulated messages */
Darren Tucker18df00c2003-11-18 12:42:07 +1100890 debug("PAM: %s", **prompts);
Damien Miller120a1ec2018-07-10 19:39:52 +1000891 if ((r = sshbuf_put(loginmsg, **prompts,
892 strlen(**prompts))) != 0)
893 fatal("%s: buffer error: %s",
894 __func__, ssh_err(r));
Darren Tuckerf60845f2013-06-02 08:07:31 +1000895 free(**prompts);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000896 **prompts = NULL;
897 }
898 if (type == PAM_SUCCESS) {
Darren Tuckerd5bfa8f2005-01-20 13:29:51 +1100899 if (!sshpam_authctxt->valid ||
900 (sshpam_authctxt->pw->pw_uid == 0 &&
901 options.permit_root_login != PERMIT_YES))
Darren Tucker36a3d602005-01-20 12:43:38 +1100902 fatal("Internal error: PAM auth "
903 "succeeded when it should have "
904 "failed");
Damien Miller120a1ec2018-07-10 19:39:52 +1000905 import_environments(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000906 *num = 0;
907 **echo_on = 0;
908 ctxt->pam_done = 1;
Darren Tuckerf60845f2013-06-02 08:07:31 +1000909 free(msg);
Damien Millerec0e6242019-09-13 13:14:39 +1000910 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000911 return (0);
912 }
Darren Tucker2a9bf4b2004-04-18 11:00:26 +1000913 error("PAM: %s for %s%.100s from %.100s", msg,
914 sshpam_authctxt->valid ? "" : "illegal user ",
Damien Miller3f0786b2019-01-20 10:22:18 +1100915 sshpam_authctxt->user, sshpam_rhost);
Darren Tucker439ce0d2003-10-09 14:20:15 +1000916 /* FALLTHROUGH */
Damien Miller4f9f42a2003-05-10 19:28:02 +1000917 default:
918 *num = 0;
919 **echo_on = 0;
Darren Tuckerf60845f2013-06-02 08:07:31 +1000920 free(msg);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000921 ctxt->pam_done = -1;
Damien Millerec0e6242019-09-13 13:14:39 +1000922 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000923 return (-1);
924 }
925 }
Damien Millerec0e6242019-09-13 13:14:39 +1000926 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000927 return (-1);
928}
929
Darren Tucker283b97f2016-07-15 13:49:44 +1000930/*
931 * Returns a junk password of identical length to that the user supplied.
932 * Used to mitigate timing attacks against crypt(3)/PAM stacks that
933 * vary processing time in proportion to password length.
934 */
935static char *
936fake_password(const char *wire_password)
937{
938 const char junk[] = "\b\n\r\177INCORRECT";
939 char *ret = NULL;
940 size_t i, l = wire_password != NULL ? strlen(wire_password) : 0;
941
942 if (l >= INT_MAX)
943 fatal("%s: password length too long: %zu", __func__, l);
944
945 ret = malloc(l + 1);
Darren Tuckerbee01672017-03-10 13:40:18 +1100946 if (ret == NULL)
947 return NULL;
Darren Tucker283b97f2016-07-15 13:49:44 +1000948 for (i = 0; i < l; i++)
949 ret[i] = junk[i % (sizeof(junk) - 1)];
950 ret[i] = '\0';
951 return ret;
952}
953
Damien Miller4f9f42a2003-05-10 19:28:02 +1000954/* XXX - see also comment in auth-chall.c:verify_response */
955static int
956sshpam_respond(void *ctx, u_int num, char **resp)
957{
Damien Miller120a1ec2018-07-10 19:39:52 +1000958 struct sshbuf *buffer;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000959 struct pam_ctxt *ctxt = ctx;
Darren Tucker283b97f2016-07-15 13:49:44 +1000960 char *fake;
Damien Miller120a1ec2018-07-10 19:39:52 +1000961 int r;
Damien Miller4f9f42a2003-05-10 19:28:02 +1000962
Darren Tucker1d4ebbf2006-01-29 16:46:13 +1100963 debug2("PAM: %s entering, %u responses", __func__, num);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000964 switch (ctxt->pam_done) {
965 case 1:
966 sshpam_authenticated = 1;
967 return (0);
968 case 0:
969 break;
970 default:
971 return (-1);
972 }
973 if (num != 1) {
974 error("PAM: expected one response, got %u", num);
975 return (-1);
976 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000977 if ((buffer = sshbuf_new()) == NULL)
978 fatal("%s: sshbuf_new failed", __func__);
Darren Tuckerd5bfa8f2005-01-20 13:29:51 +1100979 if (sshpam_authctxt->valid &&
980 (sshpam_authctxt->pw->pw_uid != 0 ||
Damien Miller120a1ec2018-07-10 19:39:52 +1000981 options.permit_root_login == PERMIT_YES)) {
982 if ((r = sshbuf_put_cstring(buffer, *resp)) != 0)
983 fatal("%s: buffer error: %s", __func__, ssh_err(r));
984 } else {
Darren Tucker283b97f2016-07-15 13:49:44 +1000985 fake = fake_password(*resp);
Damien Miller120a1ec2018-07-10 19:39:52 +1000986 if ((r = sshbuf_put_cstring(buffer, fake)) != 0)
987 fatal("%s: buffer error: %s", __func__, ssh_err(r));
Darren Tucker283b97f2016-07-15 13:49:44 +1000988 free(fake);
989 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000990 if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, buffer) == -1) {
991 sshbuf_free(buffer);
Damien Miller9bdba702003-11-17 21:27:55 +1100992 return (-1);
993 }
Damien Miller120a1ec2018-07-10 19:39:52 +1000994 sshbuf_free(buffer);
Damien Miller4f9f42a2003-05-10 19:28:02 +1000995 return (1);
996}
997
998static void
999sshpam_free_ctx(void *ctxtp)
1000{
1001 struct pam_ctxt *ctxt = ctxtp;
1002
Darren Tuckera8df9242004-01-15 00:15:07 +11001003 debug3("PAM: %s entering", __func__);
Darren Tucker8846a072003-10-07 11:30:15 +10001004 sshpam_thread_cleanup();
Darren Tuckerf60845f2013-06-02 08:07:31 +10001005 free(ctxt);
Damien Miller4f9f42a2003-05-10 19:28:02 +10001006 /*
1007 * We don't call sshpam_cleanup() here because we may need the PAM
1008 * handle at a later stage, e.g. when setting up a session. It's
1009 * still on the cleanup list, so pam_end() *will* be called before
1010 * the server process terminates.
1011 */
1012}
1013
1014KbdintDevice sshpam_device = {
1015 "pam",
1016 sshpam_init_ctx,
1017 sshpam_query,
1018 sshpam_respond,
1019 sshpam_free_ctx
1020};
1021
1022KbdintDevice mm_sshpam_device = {
1023 "pam",
1024 mm_sshpam_init_ctx,
1025 mm_sshpam_query,
1026 mm_sshpam_respond,
1027 mm_sshpam_free_ctx
1028};
1029
1030/*
1031 * This replaces auth-pam.c
1032 */
1033void
Damien Miller3f0786b2019-01-20 10:22:18 +11001034start_pam(struct ssh *ssh)
Damien Miller4f9f42a2003-05-10 19:28:02 +10001035{
Damien Miller3f0786b2019-01-20 10:22:18 +11001036 Authctxt *authctxt = (Authctxt *)ssh->authctxt;
1037
Damien Miller9d507da2003-05-14 15:31:12 +10001038 if (!options.use_pam)
1039 fatal("PAM: initialisation requested when UsePAM=no");
1040
Damien Miller3f0786b2019-01-20 10:22:18 +11001041 if (sshpam_init(ssh, authctxt) == -1)
Damien Miller4f9f42a2003-05-10 19:28:02 +10001042 fatal("PAM: initialisation failed");
1043}
1044
1045void
1046finish_pam(void)
1047{
Darren Tucker8846a072003-10-07 11:30:15 +10001048 sshpam_cleanup();
Damien Miller4f9f42a2003-05-10 19:28:02 +10001049}
1050
Damien Miller94bc1e72017-07-28 14:50:59 +10001051
Damien Miller1f499fd2003-08-25 13:08:49 +10001052u_int
1053do_pam_account(void)
Damien Miller4f9f42a2003-05-10 19:28:02 +10001054{
Darren Tucker77fc29e2004-09-11 23:07:03 +10001055 debug("%s: called", __func__);
Darren Tucker07705c72003-12-18 15:34:31 +11001056 if (sshpam_account_status != -1)
1057 return (sshpam_account_status);
1058
Damien Miller94bc1e72017-07-28 14:50:59 +10001059 expose_authinfo(__func__);
1060
Damien Miller1f499fd2003-08-25 13:08:49 +10001061 sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
Darren Tucker77fc29e2004-09-11 23:07:03 +10001062 debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
1063 pam_strerror(sshpam_handle, sshpam_err));
Damien Miller94cf4c82005-07-17 17:04:47 +10001064
Darren Tucker07705c72003-12-18 15:34:31 +11001065 if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
1066 sshpam_account_status = 0;
1067 return (sshpam_account_status);
Damien Miller1f499fd2003-08-25 13:08:49 +10001068 }
1069
Darren Tucker07705c72003-12-18 15:34:31 +11001070 if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
Darren Tucker17db1c42004-06-19 12:54:38 +10001071 sshpam_password_change_required(1);
Darren Tucker07705c72003-12-18 15:34:31 +11001072
1073 sshpam_account_status = 1;
1074 return (sshpam_account_status);
Damien Miller4f9f42a2003-05-10 19:28:02 +10001075}
1076
1077void
Damien Miller4f9f42a2003-05-10 19:28:02 +10001078do_pam_setcred(int init)
1079{
1080 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
Darren Tucker77fc29e2004-09-11 23:07:03 +10001081 (const void *)&store_conv);
Damien Miller4f9f42a2003-05-10 19:28:02 +10001082 if (sshpam_err != PAM_SUCCESS)
1083 fatal("PAM: failed to set PAM_CONV: %s",
1084 pam_strerror(sshpam_handle, sshpam_err));
1085 if (init) {
1086 debug("PAM: establishing credentials");
1087 sshpam_err = pam_setcred(sshpam_handle, PAM_ESTABLISH_CRED);
1088 } else {
1089 debug("PAM: reinitializing credentials");
1090 sshpam_err = pam_setcred(sshpam_handle, PAM_REINITIALIZE_CRED);
1091 }
1092 if (sshpam_err == PAM_SUCCESS) {
1093 sshpam_cred_established = 1;
1094 return;
1095 }
1096 if (sshpam_authenticated)
1097 fatal("PAM: pam_setcred(): %s",
1098 pam_strerror(sshpam_handle, sshpam_err));
1099 else
1100 debug("PAM: pam_setcred(): %s",
1101 pam_strerror(sshpam_handle, sshpam_err));
1102}
1103
Damien Miller4f9f42a2003-05-10 19:28:02 +10001104static int
Darren Tuckerf08bdb52005-05-26 19:59:48 +10001105sshpam_tty_conv(int n, sshpam_const struct pam_message **msg,
Damien Miller1f499fd2003-08-25 13:08:49 +10001106 struct pam_response **resp, void *data)
Damien Miller4f9f42a2003-05-10 19:28:02 +10001107{
1108 char input[PAM_MAX_MSG_SIZE];
Damien Miller5c3a5582003-09-23 22:12:38 +10001109 struct pam_response *reply;
Damien Miller4f9f42a2003-05-10 19:28:02 +10001110 int i;
1111
Darren Tuckerba53b832004-02-17 20:46:59 +11001112 debug3("PAM: %s called with %d messages", __func__, n);
1113
Damien Miller5c3a5582003-09-23 22:12:38 +10001114 *resp = NULL;
1115
Darren Tucker18df00c2003-11-18 12:42:07 +11001116 if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
Damien Miller4f9f42a2003-05-10 19:28:02 +10001117 return (PAM_CONV_ERR);
Damien Miller5c3a5582003-09-23 22:12:38 +10001118
Darren Tuckerd8093e42006-05-04 16:24:34 +10001119 if ((reply = calloc(n, sizeof(*reply))) == NULL)
Damien Miller5c3a5582003-09-23 22:12:38 +10001120 return (PAM_CONV_ERR);
Damien Miller5c3a5582003-09-23 22:12:38 +10001121
Damien Miller4f9f42a2003-05-10 19:28:02 +10001122 for (i = 0; i < n; ++i) {
1123 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1124 case PAM_PROMPT_ECHO_OFF:
Damien Miller5c3a5582003-09-23 22:12:38 +10001125 reply[i].resp =
Damien Millera8e06ce2003-11-21 23:48:55 +11001126 read_passphrase(PAM_MSG_MEMBER(msg, i, msg),
Damien Miller4f9f42a2003-05-10 19:28:02 +10001127 RP_ALLOW_STDIN);
Damien Miller5c3a5582003-09-23 22:12:38 +10001128 reply[i].resp_retcode = PAM_SUCCESS;
Damien Miller4f9f42a2003-05-10 19:28:02 +10001129 break;
1130 case PAM_PROMPT_ECHO_ON:
Darren Tucker0947ddf2003-11-13 11:21:31 +11001131 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
Darren Tucker22164712007-05-20 15:26:07 +10001132 if (fgets(input, sizeof input, stdin) == NULL)
1133 input[0] = '\0';
Damien Millera6fb77f2004-07-19 09:39:11 +10001134 if ((reply[i].resp = strdup(input)) == NULL)
1135 goto fail;
Damien Miller5c3a5582003-09-23 22:12:38 +10001136 reply[i].resp_retcode = PAM_SUCCESS;
Damien Miller4f9f42a2003-05-10 19:28:02 +10001137 break;
1138 case PAM_ERROR_MSG:
1139 case PAM_TEXT_INFO:
Darren Tucker0947ddf2003-11-13 11:21:31 +11001140 fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
Damien Miller5c3a5582003-09-23 22:12:38 +10001141 reply[i].resp_retcode = PAM_SUCCESS;
Damien Miller4f9f42a2003-05-10 19:28:02 +10001142 break;
1143 default:
1144 goto fail;
1145 }
1146 }
Damien Miller5c3a5582003-09-23 22:12:38 +10001147 *resp = reply;
Damien Miller4f9f42a2003-05-10 19:28:02 +10001148 return (PAM_SUCCESS);
Damien Miller5c3a5582003-09-23 22:12:38 +10001149
Damien Miller4f9f42a2003-05-10 19:28:02 +10001150 fail:
Damien Miller5c3a5582003-09-23 22:12:38 +10001151 for(i = 0; i < n; i++) {
Darren Tuckerf60845f2013-06-02 08:07:31 +10001152 free(reply[i].resp);
Damien Miller5c3a5582003-09-23 22:12:38 +10001153 }
Darren Tuckerf60845f2013-06-02 08:07:31 +10001154 free(reply);
Damien Miller4f9f42a2003-05-10 19:28:02 +10001155 return (PAM_CONV_ERR);
1156}
1157
Darren Tucker94befab2004-06-03 14:53:12 +10001158static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
Darren Tucker18df00c2003-11-18 12:42:07 +11001159
Damien Miller4f9f42a2003-05-10 19:28:02 +10001160/*
1161 * XXX this should be done in the authentication phase, but ssh1 doesn't
1162 * support that
1163 */
1164void
1165do_pam_chauthtok(void)
1166{
Damien Miller4f9f42a2003-05-10 19:28:02 +10001167 if (use_privsep)
Damien Miller1f499fd2003-08-25 13:08:49 +10001168 fatal("Password expired (unable to change with privsep)");
Damien Miller4f9f42a2003-05-10 19:28:02 +10001169 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
Darren Tucker18df00c2003-11-18 12:42:07 +11001170 (const void *)&tty_conv);
Damien Miller4f9f42a2003-05-10 19:28:02 +10001171 if (sshpam_err != PAM_SUCCESS)
1172 fatal("PAM: failed to set PAM_CONV: %s",
1173 pam_strerror(sshpam_handle, sshpam_err));
1174 debug("PAM: changing password");
1175 sshpam_err = pam_chauthtok(sshpam_handle, PAM_CHANGE_EXPIRED_AUTHTOK);
1176 if (sshpam_err != PAM_SUCCESS)
1177 fatal("PAM: pam_chauthtok(): %s",
1178 pam_strerror(sshpam_handle, sshpam_err));
1179}
1180
Darren Tucker18df00c2003-11-18 12:42:07 +11001181void
djm@openbsd.org7c856852018-03-03 03:15:51 +00001182do_pam_session(struct ssh *ssh)
Darren Tucker18df00c2003-11-18 12:42:07 +11001183{
Darren Tucker1921ed92004-02-10 13:23:28 +11001184 debug3("PAM: opening session");
Damien Miller94bc1e72017-07-28 14:50:59 +10001185
1186 expose_authinfo(__func__);
1187
Damien Millera8e06ce2003-11-21 23:48:55 +11001188 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
Darren Tucker5cf8ef72004-02-17 23:20:07 +11001189 (const void *)&store_conv);
Darren Tucker18df00c2003-11-18 12:42:07 +11001190 if (sshpam_err != PAM_SUCCESS)
1191 fatal("PAM: failed to set PAM_CONV: %s",
1192 pam_strerror(sshpam_handle, sshpam_err));
1193 sshpam_err = pam_open_session(sshpam_handle, 0);
Darren Tucker69687f42004-09-11 22:17:26 +10001194 if (sshpam_err == PAM_SUCCESS)
1195 sshpam_session_open = 1;
1196 else {
1197 sshpam_session_open = 0;
djm@openbsd.org7c856852018-03-03 03:15:51 +00001198 auth_restrict_session(ssh);
Darren Tucker69687f42004-09-11 22:17:26 +10001199 error("PAM: pam_open_session(): %s",
Darren Tucker18df00c2003-11-18 12:42:07 +11001200 pam_strerror(sshpam_handle, sshpam_err));
Darren Tucker69687f42004-09-11 22:17:26 +10001201 }
1202
1203}
1204
1205int
1206is_pam_session_open(void)
1207{
1208 return sshpam_session_open;
Darren Tucker18df00c2003-11-18 12:42:07 +11001209}
1210
Damien Millera8e06ce2003-11-21 23:48:55 +11001211/*
Darren Tucker49aaf4a2003-08-26 11:58:16 +10001212 * Set a PAM environment string. We need to do this so that the session
1213 * modules can handle things like Kerberos/GSI credentials that appear
1214 * during the ssh authentication process.
1215 */
Darren Tucker49aaf4a2003-08-26 11:58:16 +10001216int
Damien Millera8e06ce2003-11-21 23:48:55 +11001217do_pam_putenv(char *name, char *value)
Darren Tucker49aaf4a2003-08-26 11:58:16 +10001218{
Darren Tucker49aaf4a2003-08-26 11:58:16 +10001219 int ret = 1;
Damien Millerf2728092003-09-17 07:24:25 +10001220 char *compound;
1221 size_t len;
1222
1223 len = strlen(name) + strlen(value) + 2;
1224 compound = xmalloc(len);
1225
1226 snprintf(compound, len, "%s=%s", name, value);
1227 ret = pam_putenv(sshpam_handle, compound);
Darren Tuckerf60845f2013-06-02 08:07:31 +10001228 free(compound);
Damien Millerf2728092003-09-17 07:24:25 +10001229
Darren Tucker49aaf4a2003-08-26 11:58:16 +10001230 return (ret);
1231}
1232
Damien Miller4f9f42a2003-05-10 19:28:02 +10001233char **
Damien Millerc756e9b2003-11-17 21:41:42 +11001234fetch_pam_child_environment(void)
1235{
1236 return sshpam_env;
1237}
1238
1239char **
Damien Miller4f9f42a2003-05-10 19:28:02 +10001240fetch_pam_environment(void)
1241{
Damien Miller4f9f42a2003-05-10 19:28:02 +10001242 return (pam_getenvlist(sshpam_handle));
Damien Miller4f9f42a2003-05-10 19:28:02 +10001243}
1244
1245void
1246free_pam_environment(char **env)
1247{
1248 char **envp;
1249
Damien Millere27c6cc2003-05-16 18:21:01 +10001250 if (env == NULL)
1251 return;
1252
Damien Miller4f9f42a2003-05-10 19:28:02 +10001253 for (envp = env; *envp; envp++)
Darren Tuckerf60845f2013-06-02 08:07:31 +10001254 free(*envp);
1255 free(env);
Damien Millere72b7af1999-12-30 15:08:44 +11001256}
1257
Darren Tucker450a1582004-05-30 20:43:59 +10001258/*
1259 * "Blind" conversation function for password authentication. Assumes that
1260 * echo-off prompts are for the password and stores messages for later
1261 * display.
1262 */
1263static int
Darren Tuckerf08bdb52005-05-26 19:59:48 +10001264sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
Darren Tucker450a1582004-05-30 20:43:59 +10001265 struct pam_response **resp, void *data)
1266{
1267 struct pam_response *reply;
Damien Miller120a1ec2018-07-10 19:39:52 +10001268 int r, i;
Darren Tucker450a1582004-05-30 20:43:59 +10001269 size_t len;
1270
1271 debug3("PAM: %s called with %d messages", __func__, n);
1272
1273 *resp = NULL;
1274
1275 if (n <= 0 || n > PAM_MAX_NUM_MSG)
1276 return (PAM_CONV_ERR);
1277
Darren Tucker29171e92007-05-20 15:20:08 +10001278 if ((reply = calloc(n, sizeof(*reply))) == NULL)
Darren Tucker450a1582004-05-30 20:43:59 +10001279 return (PAM_CONV_ERR);
Darren Tucker450a1582004-05-30 20:43:59 +10001280
1281 for (i = 0; i < n; ++i) {
1282 switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
1283 case PAM_PROMPT_ECHO_OFF:
1284 if (sshpam_password == NULL)
1285 goto fail;
Damien Millera6fb77f2004-07-19 09:39:11 +10001286 if ((reply[i].resp = strdup(sshpam_password)) == NULL)
1287 goto fail;
Darren Tucker450a1582004-05-30 20:43:59 +10001288 reply[i].resp_retcode = PAM_SUCCESS;
1289 break;
1290 case PAM_ERROR_MSG:
1291 case PAM_TEXT_INFO:
1292 len = strlen(PAM_MSG_MEMBER(msg, i, msg));
1293 if (len > 0) {
Damien Miller120a1ec2018-07-10 19:39:52 +10001294 if ((r = sshbuf_putf(loginmsg, "%s\n",
1295 PAM_MSG_MEMBER(msg, i, msg))) != 0)
1296 fatal("%s: buffer error: %s",
1297 __func__, ssh_err(r));
Darren Tucker450a1582004-05-30 20:43:59 +10001298 }
Damien Millera6fb77f2004-07-19 09:39:11 +10001299 if ((reply[i].resp = strdup("")) == NULL)
1300 goto fail;
Darren Tucker450a1582004-05-30 20:43:59 +10001301 reply[i].resp_retcode = PAM_SUCCESS;
1302 break;
1303 default:
1304 goto fail;
1305 }
1306 }
1307 *resp = reply;
1308 return (PAM_SUCCESS);
1309
Damien Miller94cf4c82005-07-17 17:04:47 +10001310 fail:
Darren Tucker450a1582004-05-30 20:43:59 +10001311 for(i = 0; i < n; i++) {
Darren Tuckerf60845f2013-06-02 08:07:31 +10001312 free(reply[i].resp);
Darren Tucker450a1582004-05-30 20:43:59 +10001313 }
Darren Tuckerf60845f2013-06-02 08:07:31 +10001314 free(reply);
Darren Tucker450a1582004-05-30 20:43:59 +10001315 return (PAM_CONV_ERR);
1316}
1317
1318static struct pam_conv passwd_conv = { sshpam_passwd_conv, NULL };
1319
1320/*
1321 * Attempt password authentication via PAM
1322 */
1323int
1324sshpam_auth_passwd(Authctxt *authctxt, const char *password)
1325{
1326 int flags = (options.permit_empty_passwd == 0 ?
1327 PAM_DISALLOW_NULL_AUTHTOK : 0);
Darren Tucker283b97f2016-07-15 13:49:44 +10001328 char *fake = NULL;
Darren Tucker450a1582004-05-30 20:43:59 +10001329
1330 if (!options.use_pam || sshpam_handle == NULL)
1331 fatal("PAM: %s called when PAM disabled or failed to "
1332 "initialise.", __func__);
1333
1334 sshpam_password = password;
1335 sshpam_authctxt = authctxt;
1336
Darren Tuckere061b152004-05-30 22:04:56 +10001337 /*
1338 * If the user logging in is invalid, or is root but is not permitted
1339 * by PermitRootLogin, use an invalid password to prevent leaking
1340 * information via timing (eg if the PAM config has a delay on fail).
1341 */
Darren Tuckerd5bfa8f2005-01-20 13:29:51 +11001342 if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
Damien Miller37294fb2005-07-17 17:18:49 +10001343 options.permit_root_login != PERMIT_YES))
Darren Tucker283b97f2016-07-15 13:49:44 +10001344 sshpam_password = fake = fake_password(password);
Darren Tuckere061b152004-05-30 22:04:56 +10001345
Darren Tucker450a1582004-05-30 20:43:59 +10001346 sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
1347 (const void *)&passwd_conv);
1348 if (sshpam_err != PAM_SUCCESS)
1349 fatal("PAM: %s: failed to set PAM_CONV: %s", __func__,
1350 pam_strerror(sshpam_handle, sshpam_err));
1351
1352 sshpam_err = pam_authenticate(sshpam_handle, flags);
1353 sshpam_password = NULL;
Darren Tucker283b97f2016-07-15 13:49:44 +10001354 free(fake);
Darren Tucker01558b72016-07-18 09:33:25 +10001355 if (sshpam_err == PAM_MAXTRIES)
1356 sshpam_set_maxtries_reached(1);
Darren Tuckerd5bfa8f2005-01-20 13:29:51 +11001357 if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
Darren Tucker450a1582004-05-30 20:43:59 +10001358 debug("PAM: password authentication accepted for %.100s",
1359 authctxt->user);
Damien Miller37294fb2005-07-17 17:18:49 +10001360 return 1;
Darren Tucker450a1582004-05-30 20:43:59 +10001361 } else {
1362 debug("PAM: password authentication failed for %.100s: %s",
1363 authctxt->valid ? authctxt->user : "an illegal user",
1364 pam_strerror(sshpam_handle, sshpam_err));
1365 return 0;
1366 }
1367}
Darren Tucker01558b72016-07-18 09:33:25 +10001368
1369int
1370sshpam_get_maxtries_reached(void)
1371{
1372 return sshpam_maxtries_reached;
1373}
1374
1375void
1376sshpam_set_maxtries_reached(int reached)
1377{
1378 if (reached == 0 || sshpam_maxtries_reached)
1379 return;
1380 sshpam_maxtries_reached = 1;
1381 options.password_authentication = 0;
1382 options.kbd_interactive_authentication = 0;
1383 options.challenge_response_authentication = 0;
1384}
Damien Millere72b7af1999-12-30 15:08:44 +11001385#endif /* USE_PAM */