m4v_h263: add a test for invalid/negative value
Test: run poc with and without the patch.
Bug: 134578122
Change-Id: I2d11826d1d9e2669aa5627065dc627729ddc823b
(cherry picked from commit 7802c68aebf7908983508fd4a52a7d53746a80eb)
diff --git a/media/libstagefright/codecs/m4v_h263/dec/src/packet_util.cpp b/media/libstagefright/codecs/m4v_h263/dec/src/packet_util.cpp
index 48414d7..5880e32 100644
--- a/media/libstagefright/codecs/m4v_h263/dec/src/packet_util.cpp
+++ b/media/libstagefright/codecs/m4v_h263/dec/src/packet_util.cpp
@@ -52,7 +52,11 @@
PV_BitstreamByteAlign(stream);
BitstreamReadBits32(stream, resync_marker_length);
- *next_MB = (int) BitstreamReadBits16(stream, nbits);
+ int mbnum = (int) BitstreamReadBits16(stream, nbits);
+ if (mbnum < 0) {
+ return PV_FAIL;
+ }
+ *next_MB = mbnum;
// if (*next_MB <= video->mbnum) /* needs more investigation */
// *next_MB = video->mbnum+1;