[FFmpeg-devel] [PATCH 5/5] avcodec/mjpeg_parser: Make parser a bit more robust with unclean input

Paul B Mahol onemda at gmail.com
Sat Nov 16 15:53:29 EET 2019


So you gonna commit this or not? Are there obvious drawbacks?

On 10/11/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> Helps: test_roman.mjpeg (note this is not really just mjpeg)
>
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/mjpeg_parser.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/mjpeg_parser.c b/libavcodec/mjpeg_parser.c
> index 07a6b2bdc6..c642b2ecbc 100644
> --- a/libavcodec/mjpeg_parser.c
> +++ b/libavcodec/mjpeg_parser.c
> @@ -50,7 +50,7 @@ static int find_frame_end(MJPEGParserContext *m, const
> uint8_t *buf, int buf_siz
>          for(i=0; i<buf_size;){
>              state= (state<<8) | buf[i];
>              if(state>=0xFFC00000 && state<=0xFFFEFFFF){
> -                if(state>=0xFFD80000 && state<=0xFFD8FFFF){
> +                if(state>=0xFFD8FFC0 && state<=0xFFD8FFFF){
>                      i++;
>                      vop_found=1;
>                      break;
> @@ -76,12 +76,14 @@ static int find_frame_end(MJPEGParserContext *m, const
> uint8_t *buf, int buf_siz
>          for(; i<buf_size;){
>              state= (state<<8) | buf[i];
>              if(state>=0xFFC00000 && state<=0xFFFEFFFF){
> -                if(state>=0xFFD80000 && state<=0xFFD8FFFF){
> +                if(state>=0xFFD8FFC0 && state<=0xFFD8FFFF){
>                      pc->frame_start_found=0;
>                      pc->state=0;
>                      return i-3;
>                  } else if(state<0xFFD00000 || state>0xFFD9FFFF){
>                      m->size= (state&0xFFFF)-1;
> +                    if (m->size >= 0x8000)
> +                        m->size = 0;
>                  }
>              }
>              if(m->size>0){
> --
> 2.23.0
>
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