Re: [FFmpeg-devel] [PATCH 3/4] avformat/mxfdec: Check for avio_read() failure in mxf_read_strong_ref_array()

[Marton Balint <cus@passwd.hu>]

On Mon, 14 Mar 2022, Michael Niedermayer wrote:

> On Sun, Mar 13, 2022 at 04:52:25PM +0100, Marton Balint wrote:
>>
>>
>> On Sun, 13 Mar 2022, Michael Niedermayer wrote:
>>
>>> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
>>> ---
>>> libavformat/mxfdec.c | 8 +++++++-
>>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
>>> index d7cdd22c8a..828fc0f9f1 100644
>>> --- a/libavformat/mxfdec.c
>>> +++ b/libavformat/mxfdec.c
>>> @@ -932,6 +932,7 @@ static int mxf_read_cryptographic_context(void *arg, AVIOContext *pb, int tag, i
>>>
>>> static int mxf_read_strong_ref_array(AVIOContext *pb, UID **refs, int *count)
>>> {
>>> +    int64_t ret;
>>>     unsigned c = avio_rb32(pb);
>>>
>>>     //avio_read() used int
>>> @@ -946,7 +947,12 @@ static int mxf_read_strong_ref_array(AVIOContext *pb, UID **refs, int *count)
>>>         return AVERROR(ENOMEM);
>>>     }
>>>     avio_skip(pb, 4); /* useless size of objects, always 16 according to specs */
>>> -    avio_read(pb, (uint8_t *)*refs, *count * sizeof(UID));
>>> +    ret = avio_read(pb, (uint8_t *)*refs, *count * sizeof(UID));
>>> +    if (ret != *count * sizeof(UID)) {
>>> +        *count = ret < 0 ? 0   : ret / sizeof(UID);
>>
>
>> I suggest you hard fail if the read count is not the expected, do not
>> silently ignore corrupt file.
>>
>> Regards,
>> Marton
>>
>>> +        return   ret < 0 ? ret : AVERROR_INVALIDDATA;
>
> Does it not hard fail here ?

Yeah, it does, sorry. This extra count calculation confused me... I'd just 
probably set it to 0 in case of a partial read, same as in case of an 
error, but fine either way I guess.

Regards,
Marton
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