Bug 1071: fix delivery logging with untrusted macros.

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

diff --git a/src/src/exim.c b/src/src/exim.c
index dd3b5f9e7ecc38ed1932ab81804d5e29886cf295..e236975061be2c14ee851ac0979a200b8cb90ddd 100644 (file)
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -942,6 +942,17 @@ DEBUG(D_any) do {
       lookup_list[i]->version_report(f);
     }
 
+#ifdef WHITELIST_D_MACROS
+  fprintf(f, "WHITELIST_D_MACROS: \"%s\"\n", WHITELIST_D_MACROS);
+#else
+  fprintf(f, "WHITELIST_D_MACROS unset\n");
+#endif
+#ifdef TRUSTED_CONFIG_LIST
+  fprintf(f, "TRUSTED_CONFIG_LIST: \"%s\"\n", TRUSTED_CONFIG_LIST);
+#else
+  fprintf(f, "TRUSTED_CONFIG_LIST unset\n");
+#endif
+
 } while (0);
 }
 
@@ -1300,7 +1311,7 @@ int  arg_error_handling = error_handling;
 int  filter_sfd = -1;
 int  filter_ufd = -1;
 int  group_count;
-int  i;
+int  i, rv;
 int  list_queue_option = 0;
 int  msg_action = 0;
 int  msg_action_arg = -1;
@@ -1639,8 +1650,20 @@ real_gid = getgid();
 
 if (real_uid == root_uid)
   {
-  setgid(real_gid);
-  setuid(real_uid);
+  rv = setgid(real_gid);
+  if (rv)
+    {
+    fprintf(stderr, "exim: setgid(%ld) failed: %s\n",
+        (long int)real_gid, strerror(errno));
+    exit(EXIT_FAILURE);
+    }
+  rv = setuid(real_uid);
+  if (rv)
+    {
+    fprintf(stderr, "exim: setuid(%ld) failed: %s\n",
+        (long int)real_uid, strerror(errno));
+    exit(EXIT_FAILURE);
+    }
   }
 
 /* If neither the original real uid nor the original euid was root, Exim is
@@ -3315,9 +3338,13 @@ if ((                                            /* EITHER */
   and should be used for any logging information because attempts to write
   to the log will usually fail. To arrange this, we unset really_exim. However,
   if no stderr is available there is no point - we might as well have a go
-  at the log (if it fails, syslog will be written). */
+  at the log (if it fails, syslog will be written).
+
+  Note that if the invoker is Exim, the logs remain available. Messing with
+  this causes unlogged successful deliveries.  */
 
-  if (log_stderr != NULL) really_exim = FALSE;
+  if ((log_stderr != NULL) && (real_uid != exim_uid))
+    really_exim = FALSE;
   }
 
 /* Privilege is to be retained for the moment. It may be dropped later,
@@ -3862,7 +3889,28 @@ if (!unprivileged &&                      /* originally had root AND */
 
 /* When we are retaining a privileged uid, we still change to the exim gid. */
 
-else setgid(exim_gid);
+else
+  {
+  int rv;
+  rv = setgid(exim_gid);
+  /* Impact of failure is that some stuff might end up with an incorrect group.
+  We track this for failures from root, since any attempt to change privilege
+  by root should succeed and failures should be examined.  For non-root,
+  there's no security risk.  For me, it's { exim -bV } on a just-built binary,
+  no need to complain then. */
+  if (rv == -1)
+    {
+    if (!(unprivileged || removed_privilege))
+      {
+      fprintf(stderr,
+          "exim: changing group failed: %s\n", strerror(errno));
+      exit(EXIT_FAILURE);
+      }
+    else
+      DEBUG(D_any) debug_printf("changing group to %ld failed: %s\n",
+          (long int)exim_gid, strerror(errno));
+    }
+  }
 
 /* Handle a request to scan a file for malware */
 if (malware_test_file)