avformat/mov: Break out early if chunk_count is 0 in mov_build_index()

Without this some operations might overflow (undefined behavior) even though the index adding loop would never execute No testcase known Signed-off-by: Michael Niedermayer <[email protected]>
linhongxiu · May 20, 2018 · 56e76bd · 56e76bd
1 parent fac5849
commit 56e76bd
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/libavformat/mov.c b/libavformat/mov.c
@@ -3900,6 +3900,9 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
     } else {
         unsigned chunk_samples, total = 0;
 
+        if (!sc->chunk_count)
+            return;
+
         // compute total chunk count
         for (i = 0; i < sc->stsc_count; i++) {
             unsigned count, chunk_count;