[FFmpeg-devel] [PATCH] avcodec/jpeg2000dec: Explicitly cast quad_width and quad_height to size_t

[James Almer]

On 4/25/2023 5:13 PM, Pierre-Anthony Lemieux wrote:
> On Tue, Apr 25, 2023 at 11:25 AM <etemesicaleb at gmail.com> wrote:
>>
>> From: caleb <etemesicaleb at gmail.com>
>>
>> Prevents un-necessary casts when calculating buf_size
> 
> This is to address Coverity CID 1528149: """Suspicious implicit sign
> extension: "quad_height" with type "uint16_t const" (16 bits,
> unsigned) is promoted in "4 * quad_width * quad_height" to type "int"
> (32 bits, signed), then sign-extended to type "unsigned long" (64
> bits, unsigned).  If "4 * quad_width * quad_height" is greater than
> 0x7FFFFFFF, the upper bits of the result will all be 1."""
> 
>> ---
>>   libavcodec/jpeg2000htdec.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/libavcodec/jpeg2000htdec.c b/libavcodec/jpeg2000htdec.c
>> index 51cd96e0f1..8907820806 100644
>> --- a/libavcodec/jpeg2000htdec.c
>> +++ b/libavcodec/jpeg2000htdec.c
>> @@ -592,8 +592,8 @@ static int jpeg2000_decode_ht_cleanup_segment(const Jpeg2000DecoderContext *s,
>>       const uint16_t is_border_x = width % 2;
>>       const uint16_t is_border_y = height % 2;
>>
>> -    const uint16_t quad_width  = ff_jpeg2000_ceildivpow2(width, 1);
>> -    const uint16_t quad_height = ff_jpeg2000_ceildivpow2(height, 1);
>> +    const size_t quad_width  = ff_jpeg2000_ceildivpow2(width, 1);
>> +    const size_t quad_height = ff_jpeg2000_ceildivpow2(height, 1);
> 
> Shouldn't quad_width and quad_height be kept as uint16_t, and instead
> be explicitly cast to (size_t) when computing buf_size?

Or just make the 4 a 4UL.

> 
>>
>>       size_t buf_size = 4 * quad_width * quad_height;
>>
>> --
>> 2.39.2
>>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".