mirrors/poky
1
0
Fork 0
mirror of https://git.yoctoproject.org/poky synced 2026-03-06 23:39:40 +01:00
Code Issues Packages Projects Releases Wiki Activity

ffmpeg: fix for CVE-2022-48434

Browse Source 
libavcodec/pthread_frame.c in FFmpeg before 5.1.2, as used in VLC and
other products, leaves stale hwaccel state in worker threads, which
allows attackers to trigger a use-after-free and execute arbitrary
code in some circumstances (e.g., hardware re-initialization upon a
mid-video SPS change when Direct3D11 is used).

(From OE-Core rev: 392f984ffd95bcd3ce4c364b40425e7808ca7719)

Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
This commit is contained in:
Narpat Mali
2023-04-28 16:58:32 +00:00
committed by Steve Sakoman
parent 75239ddd8d
commit 813d4715e4
2 changed files with 132 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

130
meta/recipes-multimedia/ffmpeg/ffmpeg/CVE-2022-48434.patch Normal file
View File

@@ -0,0 +1,130 @@
From e40c964a0678908e2c756741343ed50d6a99ee12 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 28 Apr 2023 11:45:30 +0000
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 091341f, as
this commit also solves that issue in a more general way.
CVE:CVE-2022-48434
Upstream-Status: Backport [https://github.com/FFmpeg/FFmpeg/commit/cc867f2c09d2b69cee8a0eccd62aff002cbbfe11]
Signed-off-by: Narpat Mali <narpat.mali@windriver.com>
---
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 85a6bc9..e40dced 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -145,6 +145,12 @@ 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;
#if FF_API_THREAD_SAFE_CALLBACKS
@@ -229,9 +235,17 @@ FF_ENABLE_DEPRECATION_WARNINGS
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;
@@ -294,14 +308,10 @@ 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)) {
@@ -442,6 +452,12 @@ 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);
@@ -647,6 +663,14 @@ 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");
@@ -700,13 +724,6 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
park_frame_worker_threads(fctx, thread_count);
- if (fctx->prev_thread && avctx->internal->hwaccel_priv_data !=
- fctx->prev_thread->avctx->internal->hwaccel_priv_data) {
- if (update_context_from_thread(avctx, fctx->prev_thread->avctx, 1) < 0) {
- av_log(avctx, AV_LOG_ERROR, "Failed to update user thread.\n");
- }
- }
-
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");
@@ -760,6 +777,13 @@ void ff_frame_thread_free(AVCodecContext *avctx, int thread_count)
av_freep(&fctx->threads);
ff_pthread_free(fctx, thread_ctx_offsets);
+ /* 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);
}
--
2.40.0

3
meta/recipes-multimedia/ffmpeg/ffmpeg_5.0.1.bb
View File

@@ -28,7 +28,8 @@ SRC_URI = "https://www.ffmpeg.org/releases/${BP}.tar.xz \
file://0001-avcodec-smcenc-stop-accessing-out-of-bounds-frame.patch \
file://0001-avcodec-vp3-Add-missing-check-for-av_malloc.patch \
file://0001-avformat-nutdec-Add-check-for-avformat_new_stream.patch \
"
file://CVE-2022-48434.patch \
"
SRC_URI[sha256sum] = "ef2efae259ce80a240de48ec85ecb062cecca26e4352ffb3fda562c21a93007b"