]> andersk Git - openssh.git/blobdiff - auth-pam.c
- djm@cvs.openbsd.org 2010/01/30 02:54:53
[openssh.git] / auth-pam.c
index ff4b01401b1e062902e5c26469ce61b9f8151fbc..675006e6fb25cbb7f48bb8115b8d32cb2897c2d8 100644 (file)
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+/*
+ * Copyright (c) 2003,2004 Damien Miller <djm@mindrot.org>
+ * Copyright (c) 2003,2004 Darren Tucker <dtucker@zip.com.au>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
 
 /* Based on $FreeBSD: src/crypto/openssh/auth2-pam-freebsd.c,v 1.11 2003/03/31 13:48:18 des Exp $ */
 #include "includes.h"
-RCSID("$Id$");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
 
 #ifdef USE_PAM
 #if defined(HAVE_SECURITY_PAM_APPL_H)
@@ -40,27 +65,55 @@ RCSID("$Id$");
 #include <pam/pam_appl.h>
 #endif
 
+/* OpenGroup RFC86.0 and XSSO specify no "const" on arguments */
+#ifdef PAM_SUN_CODEBASE
+# define sshpam_const          /* Solaris, HP-UX, AIX */
+#else
+# define sshpam_const  const   /* LinuxPAM, OpenPAM */
+#endif
+
+/* Ambiguity in spec: is it an array of pointers or a pointer to an array? */
+#ifdef PAM_SUN_CODEBASE
+# define PAM_MSG_MEMBER(msg, n, member) ((*(msg))[(n)].member)
+#else
+# define PAM_MSG_MEMBER(msg, n, member) ((msg)[(n)]->member)
+#endif
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "key.h"
+#include "hostfile.h"
 #include "auth.h"
 #include "auth-pam.h"
-#include "buffer.h"
-#include "bufaux.h"
 #include "canohost.h"
 #include "log.h"
-#include "monitor_wrap.h"
 #include "msg.h"
 #include "packet.h"
 #include "misc.h"
 #include "servconf.h"
 #include "ssh2.h"
-#include "xmalloc.h"
 #include "auth-options.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "monitor_wrap.h"
 
 extern ServerOptions options;
 extern Buffer loginmsg;
 extern int compat20;
 extern u_int utmp_len;
 
+/* so we don't silently change behaviour */
 #ifdef USE_POSIX_THREADS
+# error "USE_POSIX_THREADS replaced by UNSUPPORTED_POSIX_THREADS_HACK"
+#endif
+
+/*
+ * Formerly known as USE_POSIX_THREADS, using this is completely unsupported
+ * and generally a bad idea.  Use at own risk and do not expect support if
+ * this breaks.
+ */
+#ifdef UNSUPPORTED_POSIX_THREADS_HACK
 #include <pthread.h>
 /*
  * Avoid namespace clash when *not* using pthreads for systems *with*
@@ -82,7 +135,7 @@ struct pam_ctxt {
 static void sshpam_free_ctx(void *);
 static struct pam_ctxt *cleanup_ctxt;
 
-#ifndef USE_POSIX_THREADS
+#ifndef UNSUPPORTED_POSIX_THREADS_HACK
 /*
  * Simulate threads with processes.
  */
@@ -90,40 +143,43 @@ static struct pam_ctxt *cleanup_ctxt;
 static int sshpam_thread_status = -1;
 static mysig_t sshpam_oldsig;
 
-static void 
+static void
 sshpam_sigchld_handler(int sig)
 {
        signal(SIGCHLD, SIG_DFL);
        if (cleanup_ctxt == NULL)
                return; /* handler called after PAM cleanup, shouldn't happen */
        if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, WNOHANG)
-            == -1) {
+           <= 0) {
                /* PAM thread has not exitted, privsep slave must have */
                kill(cleanup_ctxt->pam_thread, SIGTERM);
                if (waitpid(cleanup_ctxt->pam_thread, &sshpam_thread_status, 0)
-                   == -1)
+                   <= 0)
                        return; /* could not wait */
        }
        if (WIFSIGNALED(sshpam_thread_status) &&
            WTERMSIG(sshpam_thread_status) == SIGTERM)
                return; /* terminated by pthread_cancel */
        if (!WIFEXITED(sshpam_thread_status))
-               fatal("PAM: authentication thread exited unexpectedly");
+               sigdie("PAM: authentication thread exited unexpectedly");
        if (WEXITSTATUS(sshpam_thread_status) != 0)
-               fatal("PAM: authentication thread exited uncleanly");
+               sigdie("PAM: authentication thread exited uncleanly");
 }
 
+/* ARGSUSED */
 static void
-pthread_exit(void *value __unused)
+pthread_exit(void *value)
 {
        _exit(0);
 }
 
+/* ARGSUSED */
 static int
-pthread_create(sp_pthread_t *thread, const void *attr __unused,
+pthread_create(sp_pthread_t *thread, const void *attr,
     void *(*thread_start)(void *), void *arg)
 {
        pid_t pid;
+       struct pam_ctxt *ctx = arg;
 
        sshpam_thread_status = -1;
        switch ((pid = fork())) {
@@ -131,10 +187,14 @@ pthread_create(sp_pthread_t *thread, const void *attr __unused,
                error("fork(): %s", strerror(errno));
                return (-1);
        case 0:
+               close(ctx->pam_psock);
+               ctx->pam_psock = -1;
                thread_start(arg);
                _exit(1);
        default:
                *thread = pid;
+               close(ctx->pam_csock);
+               ctx->pam_csock = -1;
                sshpam_oldsig = signal(SIGCHLD, sshpam_sigchld_handler);
                return (0);
        }
@@ -147,8 +207,9 @@ pthread_cancel(sp_pthread_t thread)
        return (kill(thread, SIGTERM));
 }
 
+/* ARGSUSED */
 static int
-pthread_join(sp_pthread_t thread, void **value __unused)
+pthread_join(sp_pthread_t thread, void **value)
 {
        int status;
 
@@ -170,6 +231,7 @@ static int sshpam_account_status = -1;
 static char **sshpam_env = NULL;
 static Authctxt *sshpam_authctxt = NULL;
 static const char *sshpam_password = NULL;
+static char badpw[] = "\b\n\r\177INCORRECT";
 
 /* Some PAM implementations don't implement this */
 #ifndef HAVE_PAM_GETENVLIST
@@ -185,8 +247,33 @@ pam_getenvlist(pam_handle_t *pamh)
 }
 #endif
 
+/*
+ * Some platforms, notably Solaris, do not enforce password complexity
+ * rules during pam_chauthtok() if the real uid of the calling process
+ * is 0, on the assumption that it's being called by "passwd" run by root.
+ * This wraps pam_chauthtok and sets/restore the real uid so PAM will do
+ * the right thing.
+ */
+#ifdef SSHPAM_CHAUTHTOK_NEEDS_RUID
+static int
+sshpam_chauthtok_ruid(pam_handle_t *pamh, int flags)
+{
+       int result;
+
+       if (sshpam_authctxt == NULL)
+               fatal("PAM: sshpam_authctxt not initialized");
+       if (setreuid(sshpam_authctxt->pw->pw_uid, -1) == -1)
+               fatal("%s: setreuid failed: %s", __func__, strerror(errno));
+       result = pam_chauthtok(pamh, flags);
+       if (setreuid(0, -1) == -1)
+               fatal("%s: setreuid failed: %s", __func__, strerror(errno));
+       return result;
+}
+# define pam_chauthtok(a,b)    (sshpam_chauthtok_ruid((a), (b)))
+#endif
+
 void
-pam_password_change_required(int reqd)
+sshpam_password_change_required(int reqd)
 {
        debug3("%s %d", __func__, reqd);
        if (sshpam_authctxt == NULL)
@@ -213,14 +300,17 @@ import_environments(Buffer *b)
 
        debug3("PAM: %s entering", __func__);
 
-#ifndef USE_POSIX_THREADS
+#ifndef UNSUPPORTED_POSIX_THREADS_HACK
        /* Import variables set by do_pam_account */
        sshpam_account_status = buffer_get_int(b);
-       pam_password_change_required(buffer_get_int(b));
+       sshpam_password_change_required(buffer_get_int(b));
 
        /* Import environment from subprocess */
        num_env = buffer_get_int(b);
-       sshpam_env = xmalloc((num_env + 1) * sizeof(*sshpam_env));
+       if (num_env > 1024)
+               fatal("%s: received %u environment variables, expected <= 1024",
+                   __func__, num_env);
+       sshpam_env = xcalloc(num_env + 1, sizeof(*sshpam_env));
        debug3("PAM: num env strings %d", num_env);
        for(i = 0; i < num_env; i++)
                sshpam_env[i] = buffer_get_string(b, NULL);
@@ -248,7 +338,7 @@ import_environments(Buffer *b)
  * Conversation function for authentication thread.
  */
 static int
-sshpam_thread_conv(int n, const struct pam_message **msg,
+sshpam_thread_conv(int n, sshpam_const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
        Buffer buffer;
@@ -259,13 +349,16 @@ sshpam_thread_conv(int n, const struct pam_message **msg,
        debug3("PAM: %s entering, %d messages", __func__, n);
        *resp = NULL;
 
+       if (data == NULL) {
+               error("PAM: conversation function passed a null context");
+               return (PAM_CONV_ERR);
+       }
        ctxt = data;
        if (n <= 0 || n > PAM_MAX_NUM_MSG)
                return (PAM_CONV_ERR);
 
-       if ((reply = malloc(n * sizeof(*reply))) == NULL)
+       if ((reply = calloc(n, sizeof(*reply))) == NULL)
                return (PAM_CONV_ERR);
-       memset(reply, 0, n * sizeof(*reply));
 
        buffer_init(&buffer);
        for (i = 0; i < n; ++i) {
@@ -336,15 +429,29 @@ sshpam_thread(void *ctxtp)
        struct pam_ctxt *ctxt = ctxtp;
        Buffer buffer;
        struct pam_conv sshpam_conv;
-#ifndef USE_POSIX_THREADS
+       int flags = (options.permit_empty_passwd == 0 ?
+           PAM_DISALLOW_NULL_AUTHTOK : 0);
+#ifndef UNSUPPORTED_POSIX_THREADS_HACK
        extern char **environ;
        char **env_from_pam;
        u_int i;
        const char *pam_user;
+       const char **ptr_pam_user = &pam_user;
+       char *tz = getenv("TZ");
+
+       pam_get_item(sshpam_handle, PAM_USER,
+           (sshpam_const void **)ptr_pam_user);
 
-       pam_get_item(sshpam_handle, PAM_USER, (const void **)&pam_user);
-       setproctitle("%s [pam]", pam_user);
        environ[0] = NULL;
+       if (tz != NULL)
+               if (setenv("TZ", tz, 1) == -1)
+                       error("PAM: could not set TZ environment: %s",
+                           strerror(errno));
+
+       if (sshpam_authctxt != NULL) {
+               setproctitle("%s [pam]",
+                   sshpam_authctxt->valid ? pam_user : "unknown");
+       }
 #endif
 
        sshpam_conv.conv = sshpam_thread_conv;
@@ -358,25 +465,27 @@ sshpam_thread(void *ctxtp)
            (const void *)&sshpam_conv);
        if (sshpam_err != PAM_SUCCESS)
                goto auth_fail;
-       sshpam_err = pam_authenticate(sshpam_handle, 0);
+       sshpam_err = pam_authenticate(sshpam_handle, flags);
        if (sshpam_err != PAM_SUCCESS)
                goto auth_fail;
 
        if (compat20) {
-               if (!do_pam_account())
+               if (!do_pam_account()) {
+                       sshpam_err = PAM_ACCT_EXPIRED;
                        goto auth_fail;
+               }
                if (sshpam_authctxt->force_pwchange) {
                        sshpam_err = pam_chauthtok(sshpam_handle,
                            PAM_CHANGE_EXPIRED_AUTHTOK);
                        if (sshpam_err != PAM_SUCCESS)
                                goto auth_fail;
-                       pam_password_change_required(0);
+                       sshpam_password_change_required(0);
                }
        }
 
        buffer_put_cstring(&buffer, "OK");
 
-#ifndef USE_POSIX_THREADS
+#ifndef UNSUPPORTED_POSIX_THREADS_HACK
        /* Export variables set by do_pam_account */
        buffer_put_int(&buffer, sshpam_account_status);
        buffer_put_int(&buffer, sshpam_authctxt->force_pwchange);
@@ -395,7 +504,7 @@ sshpam_thread(void *ctxtp)
        buffer_put_int(&buffer, i);
        for(i = 0; env_from_pam != NULL && env_from_pam[i] != NULL; i++)
                buffer_put_cstring(&buffer, env_from_pam[i]);
-#endif /* USE_POSIX_THREADS */
+#endif /* UNSUPPORTED_POSIX_THREADS_HACK */
 
        /* XXX - can't do much about an error here */
        ssh_msg_send(ctxt->pam_csock, sshpam_err, &buffer);
@@ -406,7 +515,10 @@ sshpam_thread(void *ctxtp)
        buffer_put_cstring(&buffer,
            pam_strerror(sshpam_handle, sshpam_err));
        /* XXX - can't do much about an error here */
-       ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
+       if (sshpam_err == PAM_ACCT_EXPIRED)
+               ssh_msg_send(ctxt->pam_csock, PAM_ACCT_EXPIRED, &buffer);
+       else
+               ssh_msg_send(ctxt->pam_csock, PAM_AUTH_ERR, &buffer);
        buffer_free(&buffer);
        pthread_exit(NULL);
 
@@ -430,7 +542,7 @@ sshpam_thread_cleanup(void)
 }
 
 static int
-sshpam_null_conv(int n, const struct pam_message **msg,
+sshpam_null_conv(int n, sshpam_const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
        debug3("PAM: %s entering, %d messages", __func__, n);
@@ -439,21 +551,67 @@ sshpam_null_conv(int n, const struct pam_message **msg,
 
 static struct pam_conv null_conv = { sshpam_null_conv, NULL };
 
+static int
+sshpam_store_conv(int n, sshpam_const struct pam_message **msg,
+    struct pam_response **resp, void *data)
+{
+       struct pam_response *reply;
+       int i;
+       size_t len;
+
+       debug3("PAM: %s called with %d messages", __func__, n);
+       *resp = NULL;
+
+       if (n <= 0 || n > PAM_MAX_NUM_MSG)
+               return (PAM_CONV_ERR);
+
+       if ((reply = calloc(n, sizeof(*reply))) == NULL)
+               return (PAM_CONV_ERR);
+
+       for (i = 0; i < n; ++i) {
+               switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
+               case PAM_ERROR_MSG:
+               case PAM_TEXT_INFO:
+                       len = strlen(PAM_MSG_MEMBER(msg, i, msg));
+                       buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
+                       buffer_append(&loginmsg, "\n", 1 );
+                       reply[i].resp_retcode = PAM_SUCCESS;
+                       break;
+               default:
+                       goto fail;
+               }
+       }
+       *resp = reply;
+       return (PAM_SUCCESS);
+
+ fail:
+       for(i = 0; i < n; i++) {
+               if (reply[i].resp != NULL)
+                       xfree(reply[i].resp);
+       }
+       xfree(reply);
+       return (PAM_CONV_ERR);
+}
+
+static struct pam_conv store_conv = { sshpam_store_conv, NULL };
+
 void
 sshpam_cleanup(void)
 {
-       debug("PAM: cleanup");
-       if (sshpam_handle == NULL)
+       if (sshpam_handle == NULL || (use_privsep && !mm_is_monitor()))
                return;
+       debug("PAM: cleanup");
        pam_set_item(sshpam_handle, PAM_CONV, (const void *)&null_conv);
-       if (sshpam_cred_established) {
-               pam_setcred(sshpam_handle, PAM_DELETE_CRED);
-               sshpam_cred_established = 0;
-       }
        if (sshpam_session_open) {
+               debug("PAM: closing session");
                pam_close_session(sshpam_handle, PAM_SILENT);
                sshpam_session_open = 0;
        }
+       if (sshpam_cred_established) {
+               debug("PAM: deleting credentials");
+               pam_setcred(sshpam_handle, PAM_DELETE_CRED);
+               sshpam_cred_established = 0;
+       }
        sshpam_authenticated = 0;
        pam_end(sshpam_handle, sshpam_err);
        sshpam_handle = NULL;
@@ -464,11 +622,12 @@ sshpam_init(Authctxt *authctxt)
 {
        extern char *__progname;
        const char *pam_rhost, *pam_user, *user = authctxt->user;
+       const char **ptr_pam_user = &pam_user;
 
        if (sshpam_handle != NULL) {
                /* We already have a PAM context; check if the user matches */
                sshpam_err = pam_get_item(sshpam_handle,
-                   PAM_USER, (const void **)&pam_user);
+                   PAM_USER, (sshpam_const void **)ptr_pam_user);
                if (sshpam_err == PAM_SUCCESS && strcmp(user, pam_user) == 0)
                        return (0);
                pam_end(sshpam_handle, sshpam_err);
@@ -476,7 +635,7 @@ sshpam_init(Authctxt *authctxt)
        }
        debug("PAM: initializing for \"%s\"", user);
        sshpam_err =
-           pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
+           pam_start(SSHD_PAM_SERVICE, user, &store_conv, &sshpam_handle);
        sshpam_authctxt = authctxt;
 
        if (sshpam_err != PAM_SUCCESS) {
@@ -516,8 +675,11 @@ sshpam_init_ctx(Authctxt *authctxt)
        int socks[2];
 
        debug3("PAM: %s entering", __func__);
-       /* Refuse to start if we don't have PAM enabled */
-       if (!options.use_pam)
+       /*
+        * Refuse to start if we don't have PAM enabled or do_pam_account
+        * has previously failed.
+        */
+       if (!options.use_pam || sshpam_account_status == 0)
                return NULL;
 
        /* Initialize PAM */
@@ -526,8 +688,7 @@ sshpam_init_ctx(Authctxt *authctxt)
                return (NULL);
        }
 
-       ctxt = xmalloc(sizeof *ctxt);
-       memset(ctxt, 0, sizeof(*ctxt));
+       ctxt = xcalloc(1, sizeof *ctxt);
 
        /* Start the authentication thread */
        if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
@@ -558,7 +719,7 @@ sshpam_query(void *ctx, char **name, char **info,
        size_t plen;
        u_char type;
        char *msg;
-       size_t len;
+       size_t len, mlen;
 
        debug3("PAM: %s entering", __func__);
        buffer_init(&buffer);
@@ -571,26 +732,45 @@ sshpam_query(void *ctx, char **name, char **info,
        while (ssh_msg_recv(ctxt->pam_psock, &buffer) == 0) {
                type = buffer_get_char(&buffer);
                msg = buffer_get_string(&buffer, NULL);
+               mlen = strlen(msg);
                switch (type) {
                case PAM_PROMPT_ECHO_ON:
                case PAM_PROMPT_ECHO_OFF:
                        *num = 1;
-                       len = plen + strlen(msg) + 1;
-                       **prompts = xrealloc(**prompts, len);
-                       plen += snprintf(**prompts + plen, len, "%s", msg);
+                       len = plen + mlen + 1;
+                       **prompts = xrealloc(**prompts, 1, len);
+                       strlcpy(**prompts + plen, msg, len - plen);
+                       plen += mlen;
                        **echo_on = (type == PAM_PROMPT_ECHO_ON);
                        xfree(msg);
                        return (0);
                case PAM_ERROR_MSG:
                case PAM_TEXT_INFO:
                        /* accumulate messages */
-                       len = plen + strlen(msg) + 2;
-                       **prompts = xrealloc(**prompts, len);
-                       plen += snprintf(**prompts + plen, len, "%s\n", msg);
+                       len = plen + mlen + 2;
+                       **prompts = xrealloc(**prompts, 1, len);
+                       strlcpy(**prompts + plen, msg, len - plen);
+                       plen += mlen;
+                       strlcat(**prompts + plen, "\n", len - plen);
+                       plen++;
                        xfree(msg);
                        break;
-               case PAM_SUCCESS:
+               case PAM_ACCT_EXPIRED:
+                       sshpam_account_status = 0;
+                       /* FALLTHROUGH */
                case PAM_AUTH_ERR:
+                       debug3("PAM: %s", pam_strerror(sshpam_handle, type));
+                       if (**prompts != NULL && strlen(**prompts) != 0) {
+                               *info = **prompts;
+                               **prompts = NULL;
+                               *num = 0;
+                               **echo_on = 0;
+                               ctxt->pam_done = -1;
+                               xfree(msg);
+                               return 0;
+                       }
+                       /* FALLTHROUGH */
+               case PAM_SUCCESS:
                        if (**prompts != NULL) {
                                /* drain any accumulated messages */
                                debug("PAM: %s", **prompts);
@@ -600,6 +780,12 @@ sshpam_query(void *ctx, char **name, char **info,
                                **prompts = NULL;
                        }
                        if (type == PAM_SUCCESS) {
+                               if (!sshpam_authctxt->valid ||
+                                   (sshpam_authctxt->pw->pw_uid == 0 &&
+                                   options.permit_root_login != PERMIT_YES))
+                                       fatal("Internal error: PAM auth "
+                                           "succeeded when it should have "
+                                           "failed");
                                import_environments(&buffer);
                                *num = 0;
                                **echo_on = 0;
@@ -630,7 +816,7 @@ sshpam_respond(void *ctx, u_int num, char **resp)
        Buffer buffer;
        struct pam_ctxt *ctxt = ctx;
 
-       debug2("PAM: %s entering, %d responses", __func__, num);
+       debug2("PAM: %s entering, %u responses", __func__, num);
        switch (ctxt->pam_done) {
        case 1:
                sshpam_authenticated = 1;
@@ -645,7 +831,12 @@ sshpam_respond(void *ctx, u_int num, char **resp)
                return (-1);
        }
        buffer_init(&buffer);
-       buffer_put_cstring(&buffer, *resp);
+       if (sshpam_authctxt->valid &&
+           (sshpam_authctxt->pw->pw_uid != 0 ||
+           options.permit_root_login == PERMIT_YES))
+               buffer_put_cstring(&buffer, *resp);
+       else
+               buffer_put_cstring(&buffer, badpw);
        if (ssh_msg_send(ctxt->pam_psock, PAM_AUTHTOK, &buffer) == -1) {
                buffer_free(&buffer);
                return (-1);
@@ -708,19 +899,21 @@ finish_pam(void)
 u_int
 do_pam_account(void)
 {
+       debug("%s: called", __func__);
        if (sshpam_account_status != -1)
                return (sshpam_account_status);
 
        sshpam_err = pam_acct_mgmt(sshpam_handle, 0);
-       debug3("PAM: %s pam_acct_mgmt = %d", __func__, sshpam_err);
-       
+       debug3("PAM: %s pam_acct_mgmt = %d (%s)", __func__, sshpam_err,
+           pam_strerror(sshpam_handle, sshpam_err));
+
        if (sshpam_err != PAM_SUCCESS && sshpam_err != PAM_NEW_AUTHTOK_REQD) {
                sshpam_account_status = 0;
                return (sshpam_account_status);
        }
 
        if (sshpam_err == PAM_NEW_AUTHTOK_REQD)
-               pam_password_change_required(1);
+               sshpam_password_change_required(1);
 
        sshpam_account_status = 1;
        return (sshpam_account_status);
@@ -742,7 +935,7 @@ void
 do_pam_setcred(int init)
 {
        sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
-           (const void *)&null_conv);
+           (const void *)&store_conv);
        if (sshpam_err != PAM_SUCCESS)
                fatal("PAM: failed to set PAM_CONV: %s",
                    pam_strerror(sshpam_handle, sshpam_err));
@@ -766,7 +959,7 @@ do_pam_setcred(int init)
 }
 
 static int
-pam_tty_conv(int n, const struct pam_message **msg,
+sshpam_tty_conv(int n, sshpam_const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
        char input[PAM_MAX_MSG_SIZE];
@@ -780,9 +973,8 @@ pam_tty_conv(int n, const struct pam_message **msg,
        if (n <= 0 || n > PAM_MAX_NUM_MSG || !isatty(STDIN_FILENO))
                return (PAM_CONV_ERR);
 
-       if ((reply = malloc(n * sizeof(*reply))) == NULL)
+       if ((reply = calloc(n, sizeof(*reply))) == NULL)
                return (PAM_CONV_ERR);
-       memset(reply, 0, n * sizeof(*reply));
 
        for (i = 0; i < n; ++i) {
                switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
@@ -794,8 +986,10 @@ pam_tty_conv(int n, const struct pam_message **msg,
                        break;
                case PAM_PROMPT_ECHO_ON:
                        fprintf(stderr, "%s\n", PAM_MSG_MEMBER(msg, i, msg));
-                       fgets(input, sizeof input, stdin);
-                       reply[i].resp = xstrdup(input);
+                       if (fgets(input, sizeof input, stdin) == NULL)
+                               input[0] = '\0';
+                       if ((reply[i].resp = strdup(input)) == NULL)
+                               goto fail;
                        reply[i].resp_retcode = PAM_SUCCESS;
                        break;
                case PAM_ERROR_MSG:
@@ -819,7 +1013,7 @@ pam_tty_conv(int n, const struct pam_message **msg,
        return (PAM_CONV_ERR);
 }
 
-static struct pam_conv tty_conv = { pam_tty_conv, NULL };
+static struct pam_conv tty_conv = { sshpam_tty_conv, NULL };
 
 /*
  * XXX this should be done in the authentication phase, but ssh1 doesn't
@@ -842,51 +1036,6 @@ do_pam_chauthtok(void)
                    pam_strerror(sshpam_handle, sshpam_err));
 }
 
-static int
-pam_store_conv(int n, const struct pam_message **msg,
-    struct pam_response **resp, void *data)
-{
-       struct pam_response *reply;
-       int i;
-       size_t len;
-
-       debug3("PAM: %s called with %d messages", __func__, n);
-       *resp = NULL;
-
-       if (n <= 0 || n > PAM_MAX_NUM_MSG)
-               return (PAM_CONV_ERR);
-
-       if ((reply = malloc(n * sizeof(*reply))) == NULL)
-               return (PAM_CONV_ERR);
-       memset(reply, 0, n * sizeof(*reply));
-
-       for (i = 0; i < n; ++i) {
-               switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
-               case PAM_ERROR_MSG:
-               case PAM_TEXT_INFO:
-                       len = strlen(PAM_MSG_MEMBER(msg, i, msg));
-                       buffer_append(&loginmsg, PAM_MSG_MEMBER(msg, i, msg), len);
-                       buffer_append(&loginmsg, "\n", 1 );
-                       reply[i].resp_retcode = PAM_SUCCESS;
-                       break;
-               default:
-                       goto fail;
-               }
-       }
-       *resp = reply;
-       return (PAM_SUCCESS);
-
- fail:
-       for(i = 0; i < n; i++) {
-               if (reply[i].resp != NULL)
-                       xfree(reply[i].resp);
-       }
-       xfree(reply);
-       return (PAM_CONV_ERR);
-}
-
-static struct pam_conv store_conv = { pam_store_conv, NULL };
-
 void
 do_pam_session(void)
 {
@@ -897,10 +1046,21 @@ do_pam_session(void)
                fatal("PAM: failed to set PAM_CONV: %s",
                    pam_strerror(sshpam_handle, sshpam_err));
        sshpam_err = pam_open_session(sshpam_handle, 0);
-       if (sshpam_err != PAM_SUCCESS)
-               fatal("PAM: pam_open_session(): %s",
+       if (sshpam_err == PAM_SUCCESS)
+               sshpam_session_open = 1;
+       else {
+               sshpam_session_open = 0;
+               disable_forwarding();
+               error("PAM: pam_open_session(): %s",
                    pam_strerror(sshpam_handle, sshpam_err));
-       sshpam_session_open = 1;
+       }
+
+}
+
+int
+is_pam_session_open(void)
+{
+       return sshpam_session_open;
 }
 
 /*
@@ -958,7 +1118,7 @@ free_pam_environment(char **env)
  * display.
  */
 static int
-sshpam_passwd_conv(int n, const struct pam_message **msg,
+sshpam_passwd_conv(int n, sshpam_const struct pam_message **msg,
     struct pam_response **resp, void *data)
 {
        struct pam_response *reply;
@@ -972,16 +1132,16 @@ sshpam_passwd_conv(int n, const struct pam_message **msg,
        if (n <= 0 || n > PAM_MAX_NUM_MSG)
                return (PAM_CONV_ERR);
 
-       if ((reply = malloc(n * sizeof(*reply))) == NULL)
+       if ((reply = calloc(n, sizeof(*reply))) == NULL)
                return (PAM_CONV_ERR);
-       memset(reply, 0, n * sizeof(*reply));
 
        for (i = 0; i < n; ++i) {
                switch (PAM_MSG_MEMBER(msg, i, msg_style)) {
                case PAM_PROMPT_ECHO_OFF:
                        if (sshpam_password == NULL)
                                goto fail;
-                       reply[i].resp = xstrdup(sshpam_password);
+                       if ((reply[i].resp = strdup(sshpam_password)) == NULL)
+                               goto fail;
                        reply[i].resp_retcode = PAM_SUCCESS;
                        break;
                case PAM_ERROR_MSG:
@@ -992,7 +1152,8 @@ sshpam_passwd_conv(int n, const struct pam_message **msg,
                                    PAM_MSG_MEMBER(msg, i, msg), len);
                                buffer_append(&loginmsg, "\n", 1);
                        }
-                       reply[i].resp = xstrdup("");
+                       if ((reply[i].resp = strdup("")) == NULL)
+                               goto fail;
                        reply[i].resp_retcode = PAM_SUCCESS;
                        break;
                default:
@@ -1002,7 +1163,7 @@ sshpam_passwd_conv(int n, const struct pam_message **msg,
        *resp = reply;
        return (PAM_SUCCESS);
 
- fail: 
+ fail:
        for(i = 0; i < n; i++) {
                if (reply[i].resp != NULL)
                        xfree(reply[i].resp);
@@ -1029,6 +1190,15 @@ sshpam_auth_passwd(Authctxt *authctxt, const char *password)
        sshpam_password = password;
        sshpam_authctxt = authctxt;
 
+       /*
+        * If the user logging in is invalid, or is root but is not permitted
+        * by PermitRootLogin, use an invalid password to prevent leaking
+        * information via timing (eg if the PAM config has a delay on fail).
+        */
+       if (!authctxt->valid || (authctxt->pw->pw_uid == 0 &&
+           options.permit_root_login != PERMIT_YES))
+               sshpam_password = badpw;
+
        sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
            (const void *)&passwd_conv);
        if (sshpam_err != PAM_SUCCESS)
@@ -1040,7 +1210,7 @@ sshpam_auth_passwd(Authctxt *authctxt, const char *password)
        if (sshpam_err == PAM_SUCCESS && authctxt->valid) {
                debug("PAM: password authentication accepted for %.100s",
                    authctxt->user);
-               return 1;
+               return 1;
        } else {
                debug("PAM: password authentication failed for %.100s: %s",
                    authctxt->valid ? authctxt->user : "an illegal user",
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