Fix out of bounds read in error case in messenger_test.

Also got rid of two VLAs. They are overused a bit in toxcore. In
irc_syncbot, the array was uninitialised and then filled by a recv system
call. This can cause uninitialised reads if recv doesn't fill the entire
array. It could not cause out of bounds read directly, because a
NUL-terminator was in place, but both cases are undefined behaviour.

1 files changed, 3 insertions, 2 deletions

diff --git a/testing/irc_syncbot.c b/testing/irc_syncbot.c
index f122094f..83b86a19 100644
--- a/testing/irc_syncbot.c
+++ b/testing/irc_syncbot.c
@@ -300,8 +300,7 @@ int main(int argc, char *argv[])
         if (count > 0) {
             last_get = get_monotime_sec();
             ping_sent = 0;
-            VLA(uint8_t, data, count + 1);
-            data[count] = 0;
+            uint8_t *data = (uint8_t *)calloc(count + 1, 1);
             recv(sock, data, count, MSG_NOSIGNAL);
             printf("%s", data);
 
@@ -345,6 +344,8 @@ int main(int argc, char *argv[])
                     p_i = i + 1;
                 }
             }
+
+            free(data);
         }
 
         if (connected == 1) {