generic-library/ffmpeg
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pthread/mpegvideo: detect and block attempts to init frames after setup.

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This fixes race conditions that ultimately lead to memory corruption.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-03-24 00:20:05 +01:00
parent 71c2a70cbf
commit 59a4b73531
4 changed files with 23 additions and 0 deletions
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2
libavcodec/internal.h
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@ -157,4 +157,6 @@ static av_always_inline int64_t ff_samples_to_time_base(AVCodecContext *avctx,
avctx->time_base);
}
int ff_thread_can_start_frame(AVCodecContext *avctx);
#endif /* AVCODEC_INTERNAL_H */

5
libavcodec/mpegvideo.c
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@ -1134,6 +1134,11 @@ int ff_MPV_frame_start(MpegEncContext *s, AVCodecContext *avctx)
assert(s->last_picture_ptr == NULL || s->out_format != FMT_H264 ||
s->codec_id == CODEC_ID_SVQ3);
if (!ff_thread_can_start_frame(avctx)) {
av_log(avctx, AV_LOG_ERROR, "Attempt to start a frame outside SETUP state\n");
return -1;
}
/* mark & release old frames */
if (s->out_format != FMT_H264 || s->codec_id == CODEC_ID_SVQ3) {
if (s->pict_type != AV_PICTURE_TYPE_B && s->last_picture_ptr &&

11
libavcodec/pthread.c
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@ -932,6 +932,17 @@ static int *allocate_progress(PerThreadContext *p)
return p->progress[i];
}
int ff_thread_can_start_frame(AVCodecContext *avctx)
{
PerThreadContext *p = avctx->thread_opaque;
if ((avctx->active_thread_type&FF_THREAD_FRAME) && p->state != STATE_SETTING_UP &&
(avctx->codec->update_thread_context || (!avctx->thread_safe_callbacks &&
avctx->get_buffer != avcodec_default_get_buffer))) {
return 0;
}
return 1;
}
int ff_thread_get_buffer(AVCodecContext *avctx, AVFrame *f)
{
PerThreadContext *p = avctx->thread_opaque;

5
libavcodec/utils.c
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@ -2285,6 +2285,11 @@ void ff_thread_await_progress(AVFrame *f, int progress, int field)
{
}
int ff_thread_can_start_frame(AVCodecContext *avctx)
{
return 1;
}
#endif
enum AVMediaType avcodec_get_type(enum CodecID codec_id)