* [FFmpeg-devel] [PATCH] avcodec/h263dec: Check against previous dimensions instead of coded
@ 2025-01-30 1:57 Michael Niedermayer
2025-01-30 8:15 ` Kacper Michajlow
0 siblings, 1 reply; 3+ messages in thread
From: Michael Niedermayer @ 2025-01-30 1:57 UTC (permalink / raw)
To: FFmpeg development discussions and patches; +Cc: Kacper Michajlow
Fixes: out of array access
Fixes: crash-a41ef3db699013f669b076f02f36942925f5a98c
Found-by: Kacper Michajlow <kasper93@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/h263dec.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index 0c23012584e..5eefdc4602b 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -431,6 +431,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict,
MpegEncContext *s = avctx->priv_data;
int ret;
int slice_ret = 0;
+ int bak_width, bak_height;
/* no supplementary picture */
if (buf_size == 0) {
@@ -482,6 +483,9 @@ retry:
if (ret < 0)
return ret;
+ bak_width = s->width;
+ bak_height = s->height;
+
/* let's go :-) */
if (CONFIG_WMV2_DECODER && s->msmpeg4_version == MSMP4_WMV2) {
ret = ff_wmv2_decode_picture_header(s);
@@ -501,11 +505,12 @@ retry:
}
if (ret < 0 || ret == FRAME_SKIPPED) {
- if ( s->width != avctx->coded_width
- || s->height != avctx->coded_height) {
+ if ( s->width != bak_width
+ || s->height != bak_height) {
av_log(s->avctx, AV_LOG_WARNING, "Reverting picture dimensions change due to header decoding failure\n");
- s->width = avctx->coded_width;
- s->height= avctx->coded_height;
+ s->width = bak_width;
+ s->height= bak_height;
+
}
}
if (ret == FRAME_SKIPPED)
--
2.48.1
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [FFmpeg-devel] [PATCH] avcodec/h263dec: Check against previous dimensions instead of coded
2025-01-30 1:57 [FFmpeg-devel] [PATCH] avcodec/h263dec: Check against previous dimensions instead of coded Michael Niedermayer
@ 2025-01-30 8:15 ` Kacper Michajlow
2025-01-31 22:10 ` Michael Niedermayer
0 siblings, 1 reply; 3+ messages in thread
From: Kacper Michajlow @ 2025-01-30 8:15 UTC (permalink / raw)
To: Michael Niedermayer; +Cc: FFmpeg development discussions and patches
On Thu, 30 Jan 2025 at 02:57, Michael Niedermayer
<michael@niedermayer.cc> wrote:
>
> Fixes: out of array access
> Fixes: crash-a41ef3db699013f669b076f02f36942925f5a98c
>
> Found-by: Kacper Michajlow <kasper93@gmail.com>
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
> libavcodec/h263dec.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
> index 0c23012584e..5eefdc4602b 100644
> --- a/libavcodec/h263dec.c
> +++ b/libavcodec/h263dec.c
> @@ -431,6 +431,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict,
> MpegEncContext *s = avctx->priv_data;
> int ret;
> int slice_ret = 0;
> + int bak_width, bak_height;
>
> /* no supplementary picture */
> if (buf_size == 0) {
> @@ -482,6 +483,9 @@ retry:
> if (ret < 0)
> return ret;
>
> + bak_width = s->width;
> + bak_height = s->height;
> +
> /* let's go :-) */
> if (CONFIG_WMV2_DECODER && s->msmpeg4_version == MSMP4_WMV2) {
> ret = ff_wmv2_decode_picture_header(s);
> @@ -501,11 +505,12 @@ retry:
> }
>
> if (ret < 0 || ret == FRAME_SKIPPED) {
> - if ( s->width != avctx->coded_width
> - || s->height != avctx->coded_height) {
> + if ( s->width != bak_width
> + || s->height != bak_height) {
> av_log(s->avctx, AV_LOG_WARNING, "Reverting picture dimensions change due to header decoding failure\n");
> - s->width = avctx->coded_width;
> - s->height= avctx->coded_height;
> + s->width = bak_width;
> + s->height= bak_height;
> +
> }
> }
> if (ret == FRAME_SKIPPED)
> --
> 2.48.1
>
Works for me. Thanks.
- Kacper
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [FFmpeg-devel] [PATCH] avcodec/h263dec: Check against previous dimensions instead of coded
2025-01-30 8:15 ` Kacper Michajlow
@ 2025-01-31 22:10 ` Michael Niedermayer
0 siblings, 0 replies; 3+ messages in thread
From: Michael Niedermayer @ 2025-01-31 22:10 UTC (permalink / raw)
To: FFmpeg development discussions and patches
[-- Attachment #1.1: Type: text/plain, Size: 2280 bytes --]
On Thu, Jan 30, 2025 at 09:15:23AM +0100, Kacper Michajlow wrote:
> On Thu, 30 Jan 2025 at 02:57, Michael Niedermayer
> <michael@niedermayer.cc> wrote:
> >
> > Fixes: out of array access
> > Fixes: crash-a41ef3db699013f669b076f02f36942925f5a98c
> >
> > Found-by: Kacper Michajlow <kasper93@gmail.com>
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> > libavcodec/h263dec.c | 13 +++++++++----
> > 1 file changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
> > index 0c23012584e..5eefdc4602b 100644
> > --- a/libavcodec/h263dec.c
> > +++ b/libavcodec/h263dec.c
> > @@ -431,6 +431,7 @@ int ff_h263_decode_frame(AVCodecContext *avctx, AVFrame *pict,
> > MpegEncContext *s = avctx->priv_data;
> > int ret;
> > int slice_ret = 0;
> > + int bak_width, bak_height;
> >
> > /* no supplementary picture */
> > if (buf_size == 0) {
> > @@ -482,6 +483,9 @@ retry:
> > if (ret < 0)
> > return ret;
> >
> > + bak_width = s->width;
> > + bak_height = s->height;
> > +
> > /* let's go :-) */
> > if (CONFIG_WMV2_DECODER && s->msmpeg4_version == MSMP4_WMV2) {
> > ret = ff_wmv2_decode_picture_header(s);
> > @@ -501,11 +505,12 @@ retry:
> > }
> >
> > if (ret < 0 || ret == FRAME_SKIPPED) {
> > - if ( s->width != avctx->coded_width
> > - || s->height != avctx->coded_height) {
> > + if ( s->width != bak_width
> > + || s->height != bak_height) {
> > av_log(s->avctx, AV_LOG_WARNING, "Reverting picture dimensions change due to header decoding failure\n");
> > - s->width = avctx->coded_width;
> > - s->height= avctx->coded_height;
> > + s->width = bak_width;
> > + s->height= bak_height;
> > +
> > }
> > }
> > if (ret == FRAME_SKIPPED)
> > --
> > 2.48.1
> >
>
> Works for me. Thanks.
will apply
thx
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Some people wanted to paint the bikeshed green, some blue and some pink.
People argued and fought, when they finally agreed, only rust was left.
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^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2025-01-31 22:10 UTC | newest]
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2025-01-30 1:57 [FFmpeg-devel] [PATCH] avcodec/h263dec: Check against previous dimensions instead of coded Michael Niedermayer
2025-01-30 8:15 ` Kacper Michajlow
2025-01-31 22:10 ` Michael Niedermayer
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