| From d4b7b3c03ee2baf0166ce49dff17ec9beff684db Mon Sep 17 00:00:00 2001 |
| From: Anton Khirnov <anton@khirnov.net> |
| Date: Fri, 2 Sep 2022 22:21:27 +0200 |
| Subject: [PATCH] lavc/pthread_frame: avoid leaving stale hwaccel state in |
| worker threads |
| |
| This state is not refcounted, so make sure it always has a well-defined |
| owner. |
| |
| Remove the block added in 091341f2ab5bd35ca1a2aae90503adc74f8d3523, as |
| this commit also solves that issue in a more general way. |
| |
| (cherry picked from commit cc867f2c09d2b69cee8a0eccd62aff002cbbfe11) |
| Signed-off-by: Anton Khirnov <anton@khirnov.net> |
| (cherry picked from commit 35aa7e70e7ec350319e7634a30d8d8aa1e6ecdda) |
| Signed-off-by: Anton Khirnov <anton@khirnov.net> |
| (cherry picked from commit 3bc28e9d1ab33627cea3c632dd6b0c33e22e93ba) |
| Signed-off-by: Anton Khirnov <anton@khirnov.net> |
| |
| CVE: CVE-2022-48434 |
| Upstream-Status: Backport [https://git.ffmpeg.org/gitweb/ffmpeg.git/commit/d4b7b3c03ee2baf0166ce49dff17ec9beff684db] |
| Signed-off-by: Ranjitsinh Rathod ranjitsinh.rathod@kpit.com |
| Comment: Hunk#6 refreshed to backport changes and other to remove patch-fuzz warnings |
| --- |
| libavcodec/pthread_frame.c | 46 +++++++++++++++++++++++++++++--------- |
| 1 file changed, 35 insertions(+), 11 deletions(-) |
| |
| diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c |
| index 36ac0ac..bbc5ba6 100644 |
| --- a/libavcodec/pthread_frame.c |
| +++ b/libavcodec/pthread_frame.c |
| @@ -135,6 +135,12 @@ typedef struct FrameThreadContext { |
| * Set for the first N packets, where N is the number of threads. |
| * While it is set, ff_thread_en/decode_frame won't return any results. |
| */ |
| + |
| + /* hwaccel state is temporarily stored here in order to transfer its ownership |
| + * to the next decoding thread without the need for extra synchronization */ |
| + const AVHWAccel *stash_hwaccel; |
| + void *stash_hwaccel_context; |
| + void *stash_hwaccel_priv; |
| } FrameThreadContext; |
| |
| #define THREAD_SAFE_CALLBACKS(avctx) \ |
| @@ -211,9 +217,17 @@ static attribute_align_arg void *frame_worker_thread(void *arg) |
| ff_thread_finish_setup(avctx); |
| |
| if (p->hwaccel_serializing) { |
| + /* wipe hwaccel state to avoid stale pointers lying around; |
| + * the state was transferred to FrameThreadContext in |
| + * ff_thread_finish_setup(), so nothing is leaked */ |
| + avctx->hwaccel = NULL; |
| + avctx->hwaccel_context = NULL; |
| + avctx->internal->hwaccel_priv_data = NULL; |
| + |
| p->hwaccel_serializing = 0; |
| pthread_mutex_unlock(&p->parent->hwaccel_mutex); |
| } |
| + av_assert0(!avctx->hwaccel); |
| |
| if (p->async_serializing) { |
| p->async_serializing = 0; |
| @@ -275,14 +289,10 @@ static int update_context_from_thread(AVCodecContext *dst, AVCodecContext *src, |
| dst->color_range = src->color_range; |
| dst->chroma_sample_location = src->chroma_sample_location; |
| |
| - dst->hwaccel = src->hwaccel; |
| - dst->hwaccel_context = src->hwaccel_context; |
| - |
| dst->channels = src->channels; |
| dst->sample_rate = src->sample_rate; |
| dst->sample_fmt = src->sample_fmt; |
| dst->channel_layout = src->channel_layout; |
| - dst->internal->hwaccel_priv_data = src->internal->hwaccel_priv_data; |
| |
| if (!!dst->hw_frames_ctx != !!src->hw_frames_ctx || |
| (dst->hw_frames_ctx && dst->hw_frames_ctx->data != src->hw_frames_ctx->data)) { |
| @@ -415,6 +425,12 @@ static int submit_packet(PerThreadContext *p, AVCodecContext *user_avctx, |
| pthread_mutex_unlock(&p->mutex); |
| return err; |
| } |
| + |
| + /* transfer hwaccel state stashed from previous thread, if any */ |
| + av_assert0(!p->avctx->hwaccel); |
| + FFSWAP(const AVHWAccel*, p->avctx->hwaccel, fctx->stash_hwaccel); |
| + FFSWAP(void*, p->avctx->hwaccel_context, fctx->stash_hwaccel_context); |
| + FFSWAP(void*, p->avctx->internal->hwaccel_priv_data, fctx->stash_hwaccel_priv); |
| } |
| |
| av_packet_unref(&p->avpkt); |
| @@ -616,6 +632,14 @@ void ff_thread_finish_setup(AVCodecContext *avctx) { |
| async_lock(p->parent); |
| } |
| |
| + /* save hwaccel state for passing to the next thread; |
| + * this is done here so that this worker thread can wipe its own hwaccel |
| + * state after decoding, without requiring synchronization */ |
| + av_assert0(!p->parent->stash_hwaccel); |
| + p->parent->stash_hwaccel = avctx->hwaccel; |
| + p->parent->stash_hwaccel_context = avctx->hwaccel_context; |
| + p->parent->stash_hwaccel_priv = avctx->internal->hwaccel_priv_data; |
| + |
| pthread_mutex_lock(&p->progress_mutex); |
| if(atomic_load(&p->state) == STATE_SETUP_FINISHED){ |
| av_log(avctx, AV_LOG_WARNING, "Multiple ff_thread_finish_setup() calls\n"); |
| @@ -657,13 +681,6 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count) |
| |
| park_frame_worker_threads(fctx, thread_count); |
| |
| - if (fctx->prev_thread && fctx->prev_thread != fctx->threads) |
| - if (update_context_from_thread(fctx->threads->avctx, fctx->prev_thread->avctx, 0) < 0) { |
| - av_log(avctx, AV_LOG_ERROR, "Final thread update failed\n"); |
| - fctx->prev_thread->avctx->internal->is_copy = fctx->threads->avctx->internal->is_copy; |
| - fctx->threads->avctx->internal->is_copy = 1; |
| - } |
| - |
| for (i = 0; i < thread_count; i++) { |
| PerThreadContext *p = &fctx->threads[i]; |
| |
| @@ -713,6 +730,13 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count) |
| pthread_mutex_destroy(&fctx->async_mutex); |
| pthread_cond_destroy(&fctx->async_cond); |
| |
| + /* if we have stashed hwaccel state, move it to the user-facing context, |
| + * so it will be freed in avcodec_close() */ |
| + av_assert0(!avctx->hwaccel); |
| + FFSWAP(const AVHWAccel*, avctx->hwaccel, fctx->stash_hwaccel); |
| + FFSWAP(void*, avctx->hwaccel_context, fctx->stash_hwaccel_context); |
| + FFSWAP(void*, avctx->internal->hwaccel_priv_data, fctx->stash_hwaccel_priv); |
| + |
| av_freep(&avctx->internal->thread_ctx); |
| |
| if (avctx->priv_data && avctx->codec && avctx->codec->priv_class) |
| -- |
| 2.25.1 |
| |