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| author | Jaroslav Beran <jara.beran@gmail.com> | 2017-09-20 15:14:54 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2017-09-24 02:33:48 +0200 |
| commit | 00a1e1337f22376909338a5319a378b2e2afdde8 (patch) | |
| tree | f9d8ec3251b3d3842d944e789d7e0f2b763e782b | |
| parent | 5a9415533dd064d44605b3a3896a53377b7a5ca8 (diff) | |
| download | ffmpeg-00a1e1337f22376909338a5319a378b2e2afdde8.tar.gz | |
libavdevice/v4l2: fix invalid access to struct v4l2_buffer
In case we are short of queued buffers, at first v4l2_buffer was enqueued to kernel so it's not owned by
user-space anymore. After that it's timestamp field was read, but it might be overwritten by driver at
that moment. It resulted in invalid timestamp sometimes.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavdevice/v4l2.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/libavdevice/v4l2.c b/libavdevice/v4l2.c index 17451cdb60..f087badf5c 100644 --- a/libavdevice/v4l2.c +++ b/libavdevice/v4l2.c @@ -492,6 +492,7 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt) .type = V4L2_BUF_TYPE_VIDEO_CAPTURE, .memory = V4L2_MEMORY_MMAP }; + struct timeval buf_ts; int res; pkt->size = 0; @@ -508,6 +509,8 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt) return res; } + buf_ts = buf.timestamp; + if (buf.index >= s->buffers) { av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n"); return AVERROR(EINVAL); @@ -583,7 +586,7 @@ static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt) return AVERROR(ENOMEM); } } - pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec; + pkt->pts = buf_ts.tv_sec * INT64_C(1000000) + buf_ts.tv_usec; convert_timestamp(ctx, &pkt->pts); return pkt->size; |