CVE-2020-28017: Integer overflow in receive_add_recipient()

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

diff --git a/src/src/receive.c b/src/src/receive.c
index 398250ebbbbbc8d563187e79cfd38be9b45e4edb..cf3ef4b967ad63e11903ce61500d35727ee322e1 100644 (file)
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -3,6 +3,7 @@
 *************************************************/
 
 /* Copyright (c) University of Cambridge 1995 - 2018 */
+/* Copyright (c) The Exim Maintainers 2020 */
 /* See the file NOTICE for conditions of use and distribution. */
 
 /* Code for receiving a message and setting up spool files. */
@@ -270,8 +271,8 @@ if (check_spool_space > 0 || msg_size > 0 || check_spool_inodes > 0)
       "check_space = " PR_EXIM_ARITH "K inodes = %d msg_size = %d\n",
       space, inodes, check_spool_space, check_spool_inodes, msg_size);
 
-  if ((space >= 0 && space < check_spool_space) ||
-      (inodes >= 0 && inodes < check_spool_inodes))
+  if (  space >= 0 && space + msg_size / 1024 < check_spool_space
+     || inodes >= 0 && inodes < check_spool_inodes)
     {
     log_write(0, LOG_MAIN, "spool directory space check failed: space="
       PR_EXIM_ARITH " inodes=%d", space, inodes);
@@ -488,6 +489,13 @@ if (recipients_count >= recipients_list_max)
   {
   recipient_item *oldlist = recipients_list;
   int oldmax = recipients_list_max;
+
+  const int safe_recipients_limit = INT_MAX / 2 / sizeof(recipient_item);
+  if (recipients_list_max < 0 || recipients_list_max >= safe_recipients_limit)
+    {
+    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Too many recipients: %d", recipients_list_max);
+    }
+
   recipients_list_max = recipients_list_max ? 2*recipients_list_max : 50;
   recipients_list = store_get(recipients_list_max * sizeof(recipient_item), FALSE);
   if (oldlist != NULL)
@@ -1453,7 +1461,7 @@ if (rc == OK)
   struct dirent * entry;
   DIR * tempdir;
 
-  for (tempdir = opendir(CS scandir); entry = readdir(tempdir); )
+  for (tempdir = exim_opendir(scandir); entry = readdir(tempdir); )
     if (strncmpic(US entry->d_name, US"__rfc822_", 9) == 0)
       {
       rfc822_file_path = string_sprintf("%s/%s", scandir, entry->d_name);
@@ -1783,7 +1791,7 @@ if (sender_host_address) dmarc_init();    /* initialize libopendmarc */
 ids, and fractions of a second are required. See the comments that precede the
 message id creation below. */
 
-(void)gettimeofday(&message_id_tv, NULL);
+exim_gettime(&message_id_tv);
 
 /* For other uses of the received time we can operate with granularity of one
 second, and for that we use the global variable received_time. This is for
@@ -2122,7 +2130,8 @@ OVERSIZE:
         if (newsender)
           {
           if (domain == 0 && newsender[0] != 0)
-            newsender = rewrite_address_qualify(newsender, FALSE);
+           /* deconst ok as newsender was not const */
+            newsender = US rewrite_address_qualify(newsender, FALSE);
 
           if (filter_test != FTEST_NONE || receive_check_set_sender(newsender))
             {
@@ -2502,7 +2511,7 @@ if (extract_recip)
     {
     while (recipients_count-- > 0)
       {
-      uschar *s = rewrite_address(recipients_list[recipients_count].address,
+      const uschar * s = rewrite_address(recipients_list[recipients_count].address,
         TRUE, TRUE, global_rewrite_rules, rewrite_existflags);
       tree_add_nonrecipient(s);
       }
@@ -2568,7 +2577,7 @@ if (extract_recip)
 
         If there are no recipients at all, an error will occur later. */
 
-        if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
+        if (!recipient && Ustrcmp(errmess, "empty address") != 0)
           {
           int len = Ustrlen(s);
           error_block *b = store_get(sizeof(error_block), FALSE);
@@ -2789,8 +2798,8 @@ recipients will get here only if the conditions were right (allow_unqualified_
 recipient is TRUE). */
 
 for (int i = 0; i < recipients_count; i++)
-  recipients_list[i].address =
-    rewrite_address(recipients_list[i].address, TRUE, TRUE,
+  recipients_list[i].address = /* deconst ok as src was not cont */
+    US rewrite_address(recipients_list[i].address, TRUE, TRUE,
       global_rewrite_rules, rewrite_existflags);
 
 /* If there is no From: header, generate one for local (without
@@ -2965,7 +2974,8 @@ it has already been rewritten as part of verification for SMTP input. */
 
 if (global_rewrite_rules && !sender_address_unrewritten && *sender_address)
   {
-  sender_address = rewrite_address(sender_address, FALSE, TRUE,
+  /* deconst ok as src was not const */
+  sender_address = US rewrite_address(sender_address, FALSE, TRUE,
     global_rewrite_rules, rewrite_existflags);
   DEBUG(D_receive|D_rewrite)
     debug_printf("rewritten sender = %s\n", sender_address);
@@ -4003,7 +4013,7 @@ if (LOGGING(tls_certificate_verified) && tls_in.cipher)
 if (LOGGING(tls_peerdn) && tls_in.peerdn)
   g = string_append(g, 3, US" DN=\"", string_printing(tls_in.peerdn), US"\"");
 if (LOGGING(tls_sni) && tls_in.sni)
-  g = string_append(g, 3, US" SNI=\"", string_printing(tls_in.sni), US"\"");
+  g = string_append(g, 2, US" SNI=", string_printing2(tls_in.sni, SP_TAB|SP_SPACE));
 #endif
 
 if (sender_host_authenticated)