[tor-commits] [tor/master] Don't unconditionally deref pub and sub in lint_message_consistency

[teor at torproject.org]

commit f58587a68dec2cdbcbf3d3d46414c05fc9dfffbd
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Mar 28 09:19:23 2019 -0400

    Don't unconditionally deref pub and sub in lint_message_consistency
    
    This can't actually result in a null pointer dereference, since
    pub_excl and sub_excl are only set when the corresponding smartlists
    are nonempty.  But coverity isn't smart enough to figure that out,
    and we shouldn't really be depending on it.
    
    Bug 29938; CID 1444257.  Bug not in any released Tor.
---
 src/lib/pubsub/pubsub_check.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/pubsub/pubsub_check.c b/src/lib/pubsub/pubsub_check.c
index d308dc58a..a3c22d4f2 100644
--- a/src/lib/pubsub/pubsub_check.c
+++ b/src/lib/pubsub/pubsub_check.c
@@ -303,14 +303,14 @@ lint_message_consistency(message_id_t msg,
   /* Enforce exclusive-ness for publishers and subscribers that have asked for
    * it.
    */
-  if (pub_excl && smartlist_len(pub) > 1) {
+  if (pub_excl && smartlist_len_opt(pub) > 1) {
     log_warn(LD_MESG|LD_BUG,
              "Message \"%s\" has multiple publishers, but at least one is "
              "marked as exclusive.",
              get_message_id_name(msg));
     ok = false;
   }
-  if (sub_excl && smartlist_len(sub) > 1) {
+  if (sub_excl && smartlist_len_opt(sub) > 1) {
     log_warn(LD_MESG|LD_BUG,
              "Message \"%s\" has multiple subscribers, but at least one is "
              "marked as exclusive.",