Message ID | 285a0213-2a77-fa4c-4412-e1f296423e14@googlemail.com |
---|---|
State | Accepted |
Headers | show |
On Sat, Nov 26, 2016 at 11:36:48PM +0100, Andreas Cadhalpun wrote: > On 26.11.2016 01:53, Michael Niedermayer wrote: > > On Fri, Nov 25, 2016 at 10:13:06PM +0100, Andreas Cadhalpun wrote: > >> This fixes a segmentation fault caused by calling memcpy with NULL as > >> second argument in handle_p_frame_apng. > >> > >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > >> --- > >> libavcodec/pngdec.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c > >> index 36275ae..a7b330b 100644 > >> --- a/libavcodec/pngdec.c > >> +++ b/libavcodec/pngdec.c > >> @@ -922,7 +922,7 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, > >> return AVERROR_INVALIDDATA; > >> } > >> > >> - if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS) { > >> + if (!s->previous_picture.f->data[0] && dispose_op == APNG_DISPOSE_OP_PREVIOUS) { > >> // No previous frame to revert to for the first frame > >> // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND > >> dispose_op = APNG_DISPOSE_OP_BACKGROUND; > > > > wont this be different when seeking back to the > > first frame ? > > is that intended ? > > I don't think the apng demuxer supports seeking. > But it shouldn't hurt to check both sequence_number and the previous frame. > Updated patch is attached. > > Best regards, > Andreas > > pngdec.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > 141d5230c97dbc47e0b291f660544cfe57abbf7c 0001-pngdec-check-if-previous-frame-exists-instead-of-tru.patch > From 84125e5f32fd4b9146d9926d2f8a4467da7c8557 Mon Sep 17 00:00:00 2001 > From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > Date: Fri, 25 Nov 2016 22:09:51 +0100 > Subject: [PATCH] pngdec: check if previous frame exists instead of trusting > sequence_number > > This fixes a segmentation fault caused by calling memcpy with NULL as > second argument in handle_p_frame_apng. > > Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> > --- > libavcodec/pngdec.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) LGTM thx [...]
On 27.11.2016 04:07, Michael Niedermayer wrote: > On Sat, Nov 26, 2016 at 11:36:48PM +0100, Andreas Cadhalpun wrote: >> pngdec.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> 141d5230c97dbc47e0b291f660544cfe57abbf7c 0001-pngdec-check-if-previous-frame-exists-instead-of-tru.patch >> From 84125e5f32fd4b9146d9926d2f8a4467da7c8557 Mon Sep 17 00:00:00 2001 >> From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> Date: Fri, 25 Nov 2016 22:09:51 +0100 >> Subject: [PATCH] pngdec: check if previous frame exists instead of trusting >> sequence_number >> >> This fixes a segmentation fault caused by calling memcpy with NULL as >> second argument in handle_p_frame_apng. >> >> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> >> --- >> libavcodec/pngdec.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) > > LGTM Pushed. Best regards, Andreas
From 84125e5f32fd4b9146d9926d2f8a4467da7c8557 Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> Date: Fri, 25 Nov 2016 22:09:51 +0100 Subject: [PATCH] pngdec: check if previous frame exists instead of trusting sequence_number This fixes a segmentation fault caused by calling memcpy with NULL as second argument in handle_p_frame_apng. Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> --- libavcodec/pngdec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index 36275ae..2f8d266 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -922,7 +922,8 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s, return AVERROR_INVALIDDATA; } - if (sequence_number == 0 && dispose_op == APNG_DISPOSE_OP_PREVIOUS) { + if ((sequence_number == 0 || !s->previous_picture.f->data[0]) && + dispose_op == APNG_DISPOSE_OP_PREVIOUS) { // No previous frame to revert to for the first frame // Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND dispose_op = APNG_DISPOSE_OP_BACKGROUND; -- 2.10.2