From 7fb1978249402e3f327662a629d83de64331a9c3 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sun, 26 Jan 2020 06:10:27 +0100 Subject: avformat/matroskaenc: Check BlockAdditional size before use Don't read a 64bit number before having checked that the data is at least 8 bytes long. Signed-off-by: Andreas Rheinhardt Signed-off-by: Michael Niedermayer (cherry picked from commit 6e9cc964293bf1e0cca6a52b2938a20d711e4146) Signed-off-by: Andreas Rheinhardt --- libavformat/matroskaenc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c index 4bc0aa1eca..fa33ccd23d 100644 --- a/libavformat/matroskaenc.c +++ b/libavformat/matroskaenc.c @@ -2154,9 +2154,13 @@ static int 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) { -- cgit v1.2.1