[FFmpeg-devel] [PATCH 29/30] avformat/matroskaenc: Check BlockAdditional size before use
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Sun Jan 26 07:10:27 EET 2020
Don't read a 64bit number before having checked that the data is at
least 8 bytes long.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
libavformat/matroskaenc.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
index 444032b431..8fc672a31f 100644
--- a/libavformat/matroskaenc.c
+++ b/libavformat/matroskaenc.c
@@ -2100,9 +2100,13 @@ static void mkv_write_block(AVFormatContext *s, AVIOContext *pb,
AV_PKT_DATA_MATROSKA_BLOCKADDITIONAL,
&side_data_size);
if (side_data) {
- additional_id = AV_RB64(side_data);
- side_data += 8;
- side_data_size -= 8;
+ if (side_data_size < 8) {
+ side_data_size = 0;
+ } else {
+ additional_id = AV_RB64(side_data);
+ side_data += 8;
+ side_data_size -= 8;
+ }
}
if ((side_data_size && additional_id == 1) || discard_padding) {
--
2.20.1
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