- (dtucker) [auth-pam.c auth-pam.h auth1.c auth2.c monitor.c monitor_wrap.c

   monitor_wrap.h] Bug #808: Ensure force_pwchange is correctly initialized
   even if keyboard-interactive is not used by the client.  Prevents segfaults
   in some cases where the user's password is expired (note this is not
   considered a security exposure).  ok djm@

1 files changed, 17 insertions, 12 deletions

diff --git a/auth-pam.c b/auth-pam.c
index ea361f171..6f2264c5d 100644
--- a/auth-pam.c
+++ b/auth-pam.c
@@ -31,7 +31,7 @@
 
 /* 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: auth-pam.c,v 1.97 2004/03/04 09:03:54 dtucker Exp $");
+RCSID("$Id: auth-pam.c,v 1.98 2004/03/08 12:04:06 dtucker Exp $");
 
 #ifdef USE_PAM
 #if defined(HAVE_SECURITY_PAM_APPL_H)
@@ -160,7 +160,7 @@ static int sshpam_session_open = 0;
 static int sshpam_cred_established = 0;
 static int sshpam_account_status = -1;
 static char **sshpam_env = NULL;
-static int *force_pwchange;
+static Authctxt *the_authctxt = NULL;
 
 /* Some PAM implementations don't implement this */
 #ifndef HAVE_PAM_GETENVLIST
@@ -180,7 +180,9 @@ void
 pam_password_change_required(int reqd)
 {
         debug3("%s %d", __func__, reqd);
-        *force_pwchange = reqd;
+        if (the_authctxt == NULL)
+                fatal("%s: PAM authctxt not initialized", __func__);
+        the_authctxt->force_pwchange = reqd;
         if (reqd) {
                 no_port_forwarding_flag |= 2;
                 no_agent_forwarding_flag |= 2;
@@ -339,6 +341,9 @@ sshpam_thread(void *ctxtp)
         sshpam_conv.conv = sshpam_thread_conv;
         sshpam_conv.appdata_ptr = ctxt;
 
+        if (the_authctxt == NULL)
+                fatal("%s: PAM authctxt not initialized", __func__);
+
         buffer_init(&buffer);
         sshpam_err = pam_set_item(sshpam_handle, PAM_CONV,
             (const void *)&sshpam_conv);
@@ -351,7 +356,7 @@ sshpam_thread(void *ctxtp)
         if (compat20) {
                 if (!do_pam_account())
                         goto auth_fail;
-                if (*force_pwchange) {
+                if (the_authctxt->force_pwchange) {
                         sshpam_err = pam_chauthtok(sshpam_handle,
                             PAM_CHANGE_EXPIRED_AUTHTOK);
                         if (sshpam_err != PAM_SUCCESS)
@@ -365,7 +370,7 @@ sshpam_thread(void *ctxtp)
 #ifndef USE_POSIX_THREADS
         /* Export variables set by do_pam_account */
         buffer_put_int(&buffer, sshpam_account_status);
-        buffer_put_int(&buffer, *force_pwchange);
+        buffer_put_int(&buffer, the_authctxt->force_pwchange);
 
         /* Export any environment strings set in child */
         for(i = 0; environ[i] != NULL; i++)
@@ -446,11 +451,11 @@ sshpam_cleanup(void)
 }
 
 static int
-sshpam_init(const char *user)
+sshpam_init(Authctxt *authctxt)
 {
         extern u_int utmp_len;
         extern char *__progname;
-        const char *pam_rhost, *pam_user;
+        const char *pam_rhost, *pam_user, *user = authctxt->user;
 
         if (sshpam_handle != NULL) {
                 /* We already have a PAM context; check if the user matches */
@@ -464,6 +469,8 @@ sshpam_init(const char *user)
         debug("PAM: initializing for \"%s\"", user);
         sshpam_err =
             pam_start(SSHD_PAM_SERVICE, user, &null_conv, &sshpam_handle);
+        the_authctxt = authctxt;
+
         if (sshpam_err != PAM_SUCCESS) {
                 pam_end(sshpam_handle, sshpam_err);
                 sshpam_handle = NULL;
@@ -506,7 +513,7 @@ sshpam_init_ctx(Authctxt *authctxt)
                 return NULL;
 
         /* Initialize PAM */
-        if (sshpam_init(authctxt->user) == -1) {
+        if (sshpam_init(authctxt) == -1) {
                 error("PAM: initialization failed");
                 return (NULL);
         }
@@ -514,8 +521,6 @@ sshpam_init_ctx(Authctxt *authctxt)
         ctxt = xmalloc(sizeof *ctxt);
         memset(ctxt, 0, sizeof(*ctxt));
 
-        force_pwchange = &(authctxt->force_pwchange);
-
         /* Start the authentication thread */
         if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, socks) == -1) {
                 error("PAM: failed create sockets: %s", strerror(errno));
@@ -674,12 +679,12 @@ KbdintDevice mm_sshpam_device = {
  * This replaces auth-pam.c
  */
 void
-start_pam(const char *user)
+start_pam(Authctxt *authctxt)
 {
         if (!options.use_pam)
                 fatal("PAM: initialisation requested when UsePAM=no");
 
-        if (sshpam_init(user) == -1)
+        if (sshpam_init(authctxt) == -1)
                 fatal("PAM: initialisation failed");
 }