[FFmpeg-devel] [PATCH] opt: check image size when setting it

[Andreas Cadhalpun]

On 10.12.2016 16:26, wm4 wrote:
> On Sat, 10 Dec 2016 16:11:15 +0100
> Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
> 
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>>  libavutil/opt.c | 10 +++++++++-
>>  1 file changed, 9 insertions(+), 1 deletion(-)
>>
>> diff --git a/libavutil/opt.c b/libavutil/opt.c
>> index f855ccb..f713d3f 100644
>> --- a/libavutil/opt.c
>> +++ b/libavutil/opt.c
>> @@ -32,6 +32,7 @@
>>  #include "common.h"
>>  #include "dict.h"
>>  #include "eval.h"
>> +#include "imgutils.h"
>>  #include "log.h"
>>  #include "parseutils.h"
>>  #include "pixdesc.h"
>> @@ -325,8 +326,15 @@ static int set_string_image_size(void *obj, const AVOption *o, const char *val,
>>          return 0;
>>      }
>>      ret = av_parse_video_size(dst, dst + 1, val);
>> -    if (ret < 0)
>> +    if (ret < 0) {
>>          av_log(obj, AV_LOG_ERROR, "Unable to parse option value \"%s\" as image size\n", val);
>> +        return ret;
>> +    }
>> +    ret = av_image_check_size(*dst, *(dst + 1), 0, obj);
>> +    if (ret < 0) {
>> +        *dst = 0;
>> +        *(dst + 1) = 0;
>> +    }
>>      return ret;
>>  }
>>  
> 
> I'd argue that rather than doing this, image allocation functions etc.
> should error out if the dimensions are too large.

That can be done in addition to this.

> This way the allowed dimensions could be enlarged (e.g. by taking the
> pixel format into account) without changing everything from int to
> size_t.

If that is done, the hard limit in av_image_check_size should check for
the maximum allowed value of any pixel format.
But a check here is needed to make sure that width * height doesn't overflow.

Best regards,
Andreas