[FFmpeg-cvslog] avformat/webpenc: Fix memleak when using invalid packets
Andreas Rheinhardt
git at videolan.org
Wed Mar 24 02:03:13 EET 2021
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Thu Mar 18 23:04:37 2021 +0100| [f9043de99a23e35a34c79bfbc9ef17b27f7236d1] | committer: Andreas Rheinhardt
avformat/webpenc: Fix memleak when using invalid packets
The WebP muxer sometimes caches a packet it receives to write it later;
yet if a cached packet is too small (so small as to be invalid),
it is cached, but not written and not unreferenced. Such a packet leaks,
either by being overwritten by the next packet or because it is never
unreferenced at all.
Fix this by not caching unusable packets at all; and error out on
invalid packets.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f9043de99a23e35a34c79bfbc9ef17b27f7236d1
---
libavformat/webpenc.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/libavformat/webpenc.c b/libavformat/webpenc.c
index 8c32ff66df..e3b12aeed2 100644
--- a/libavformat/webpenc.c
+++ b/libavformat/webpenc.c
@@ -53,24 +53,22 @@ static int webp_init(AVFormatContext *s)
static int is_animated_webp_packet(AVPacket *pkt)
{
- if (pkt->size) {
int skip = 0;
unsigned flags = 0;
if (pkt->size < 4)
- return 0;
+ return AVERROR_INVALIDDATA;
if (AV_RL32(pkt->data) == AV_RL32("RIFF"))
skip = 12;
-
+ // Safe to do this as a valid WebP bitstream is >=30 bytes.
if (pkt->size < skip + 4)
- return 0;
+ return AVERROR_INVALIDDATA;
if (AV_RL32(pkt->data + skip) == AV_RL32("VP8X")) {
flags |= pkt->data[skip + 4 + 4];
}
if (flags & 2) // ANIMATION_FLAG is on
return 1;
- }
return 0;
}
@@ -84,13 +82,9 @@ static int flush(AVFormatContext *s, int trailer, int64_t pts)
unsigned flags = 0;
int vp8x = 0;
- if (w->last_pkt.size < 4)
- return 0;
if (AV_RL32(w->last_pkt.data) == AV_RL32("RIFF"))
skip = 12;
- if (w->last_pkt.size < skip + 4)
- return 0; // Safe to do this as a valid WebP bitstream is >=30 bytes.
if (AV_RL32(w->last_pkt.data + skip) == AV_RL32("VP8X")) {
flags |= w->last_pkt.data[skip + 4 + 4];
vp8x = 1;
@@ -149,7 +143,14 @@ static int flush(AVFormatContext *s, int trailer, int64_t pts)
static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
{
WebpContext *w = s->priv_data;
- w->using_webp_anim_encoder |= is_animated_webp_packet(pkt);
+ int ret;
+
+ if (!pkt->size)
+ return 0;
+ ret = is_animated_webp_packet(pkt);
+ if (ret < 0)
+ return ret;
+ w->using_webp_anim_encoder |= ret;
if (w->using_webp_anim_encoder) {
avio_write(s->pb, pkt->data, pkt->size);
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