Fix CVE-2016-1531

[exim.git] / src / src / exim.c

diff --git a/src/src/exim.c b/src/src/exim.c
index ebc71dd371929028edd35f69d11745f1a5dd83dd..d6f2d4aac601c3fde28b0167461785bad131543e 100644 (file)
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -3743,8 +3743,19 @@ if (running_in_test_harness) smtputf8_advertise_hosts = NULL;
 is a failure. It leaves the configuration file open so that the subsequent
 configuration data for delivery can be read if needed. */
 
+/* To be safe: change the working directory to /. */
+if (Uchdir("/") < 0)
+  {
+    perror("exim: chdir `/': ");
+    exit(EXIT_FAILURE);
+  }
+
 readconf_main();
 
+if (cleanup_environment() == FALSE)
+  log_write(0, LOG_PANIC_DIE, "Can't cleanup environment");
+
+
 /* If an action on specific messages is requested, or if a daemon or queue
 runner is being started, we need to know if Exim was called by an admin user.
 This is the case if the real user is root or exim, or if the real group is
@@ -3899,20 +3910,23 @@ if (log_oneline)
 temporary files are created; Exim doesn't use these (apart from when delivering
 to MBX mailboxes), but called libraries such as DBM libraries may require them.
 If TMPDIR is found in the environment, reset it to the value defined in the
-TMPDIR macro, if this macro is defined. */
+EXIM_TMPDIR macro, if this macro is defined.  For backward compatibility this
+macro may be called TMPDIR in old "Local/Makefile"s. It's converted to
+EXIM_TMPDIR by the build scripts.
+*/
 
-#ifdef TMPDIR
+#ifdef EXIM_TMPDIR
   {
   uschar **p;
-  for (p = USS environ; *p != NULL; p++)
+  if (environ) for (p = USS environ; *p != NULL; p++)
     {
     if (Ustrncmp(*p, "TMPDIR=", 7) == 0 &&
-        Ustrcmp(*p+7, TMPDIR) != 0)
+        Ustrcmp(*p+7, EXIM_TMPDIR) != 0)
       {
-      uschar *newp = malloc(Ustrlen(TMPDIR) + 8);
-      sprintf(CS newp, "TMPDIR=%s", TMPDIR);
+      uschar *newp = malloc(Ustrlen(EXIM_TMPDIR) + 8);
+      sprintf(CS newp, "TMPDIR=%s", EXIM_TMPDIR);
       *p = newp;
-      DEBUG(D_any) debug_printf("reset TMPDIR=%s in environment\n", TMPDIR);
+      DEBUG(D_any) debug_printf("reset TMPDIR=%s in environment\n", EXIM_TMPDIR);
       }
     }
   }
@@ -3944,10 +3958,10 @@ else
     uschar **new;
     uschar **newp;
     int count = 0;
-    while (*p++ != NULL) count++;
+    if (environ) while (*p++ != NULL) count++;
     if (envtz == NULL) count++;
     newp = new = malloc(sizeof(uschar *) * (count + 1));
-    for (p = USS environ; *p != NULL; p++)
+    if (environ) for (p = USS environ; *p != NULL; p++)
       {
       if (Ustrncmp(*p, "TZ=", 3) == 0) continue;
       *newp++ = *p;
@@ -4537,7 +4551,8 @@ if (list_options)
           (Ustrcmp(argv[i], "router") == 0 ||
            Ustrcmp(argv[i], "transport") == 0 ||
            Ustrcmp(argv[i], "authenticator") == 0 ||
-           Ustrcmp(argv[i], "macro") == 0))
+           Ustrcmp(argv[i], "macro") == 0 ||
+           Ustrcmp(argv[i], "environment") == 0))
         {
         readconf_print(argv[i+1], argv[i], flag_n);
         i++;