Re: [FFmpeg-devel] [PATCH] Check codec_whitelist before reinitializing AVCtx.priv_data.

[Dale Curtis <dalecurtis@chromium.org>]

Bump for this one. Thanks!

- dale

On Wed, Jul 31, 2024 at 4:18 PM Dale Curtis <dalecurtis@chromium.org> wrote:

> On Wed, Jul 31, 2024 at 2:29 PM Dale Curtis <dalecurtis@chromium.org>
> wrote:
>
>> On Wed, Jul 31, 2024 at 2:10 PM Dale Curtis <dalecurtis@chromium.org>
>> wrote:
>>
>>> On Wed, Jul 31, 2024 at 4:32 AM Anton Khirnov <anton@khirnov.net> wrote:
>>>
>>>> Quoting Dale Curtis (2024-07-31 01:14:13)
>>>> > I realized there are a couple more allocations that can be skipped
>>>> here
>>>> > when a codec is not on the allow list. Here's the updated patch.
>>>> >
>>>> > - dale
>>>> >
>>>> > On Mon, Jul 29, 2024 at 10:19 AM Dale Curtis <dalecurtis@chromium.org
>>>> >
>>>> > wrote:
>>>> >
>>>> > > This ensures that if a codec isn't on codec_whitelist, its VUI
>>>> > > information can still be populated during find_stream_info()
>>>> > > via parsers.
>>>> > >
>>>> > > Signed-off-by: Dale Curtis <dalecurtis@chromium.org>
>>>> > > ---
>>>> > >  libavcodec/avcodec.c | 12 ++++++------
>>>> > >  1 file changed, 6 insertions(+), 6 deletions(-)
>>>> > >
>>>> > >
>>>> >
>>>> > From f87042d77d13c4c45f4b800146dc16347c1007d4 Mon Sep 17 00:00:00 2001
>>>> > From: Dale Curtis <dalecurtis@chromium.org>
>>>> > Date: Tue, 30 Jul 2024 23:12:21 +0000
>>>> > Subject: [PATCH] Check codec_whitelist before reinitializing
>>>> AVCtx.priv_data.
>>>> >
>>>> > This ensures that if a codec isn't on codec_whitelist, its VUI
>>>> > information can still be populated during find_stream_info()
>>>> > via parsers.
>>>>
>>>> Can you elaborate on this?
>>>>
>>>
>>> The current code reinitializes the private data structures then checks
>>> the whitelist. If the private data section had already been filled out, it
>>> ends up being overwritten causing find_stream_info to drop side channel
>>> data.
>>>
>>>
>>>> >
>>>> > Signed-off-by: Dale Curtis <dalecurtis@chromium.org>
>>>> > ---
>>>> >  libavcodec/avcodec.c | 11 +++++------
>>>> >  1 file changed, 5 insertions(+), 6 deletions(-)
>>>> >
>>>> > diff --git a/libavcodec/avcodec.c b/libavcodec/avcodec.c
>>>> > index 214dca4566..1f9b3eb360 100644
>>>> > --- a/libavcodec/avcodec.c
>>>> > +++ b/libavcodec/avcodec.c
>>>> > @@ -174,6 +174,11 @@ int attribute_align_arg
>>>> avcodec_open2(AVCodecContext *avctx, const AVCodec *code
>>>> >      if (avctx->extradata_size < 0 || avctx->extradata_size >=
>>>> FF_MAX_EXTRADATA_SIZE)
>>>> >          return AVERROR(EINVAL);
>>>> >
>>>> > +    if (avctx->codec_whitelist && av_match_list(codec->name,
>>>> avctx->codec_whitelist, ',') <= 0) {
>>>> > +        av_log(avctx, AV_LOG_ERROR, "Codec (%s) not on whitelist
>>>> \'%s\'\n", codec->name, avctx->codec_whitelist);
>>>> > +        return AVERROR(EINVAL);
>>>> > +    }
>>>>
>>>> I think this will break the case where the whitelist is provided in the
>>>> options dictionary, as it's not applied yet at this point.
>>>>
>>>
>>> I just copied the existing code a few lines up, so it seems ancillary to
>>> this patch, but I can fix it in this one too if you want.
>>>
>>
>> Nevermind, I see what you're saying -- yes this does break that case.
>> Thanks for catching. I'll send a fix shortly.
>>
>
> Fixed. Thanks.
>
>
>>
>>
>>>
>>>
>>>>
>>>> --
>>>> Anton Khirnov
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>>>>
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>>>>
>>>
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