[FFmpeg-devel] [PATCH 4/6] avcodec/flicvideo: Make line_packets int

[Michael Niedermayer]

On Sat, Jun 22, 2019 at 04:58:37PM +0200, Paul B Mahol wrote:
> On 6/22/19, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > Fixes: signed integer overflow: -32768 * 196032 cannot be represented in
> > type 'int'
> > Fixes:
> > 15300/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FLIC_fuzzer-5733319519502336
> >
> > Found-by: continuous fuzzing process
> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  libavcodec/flicvideo.c | 14 +++++++-------
> >  1 file changed, 7 insertions(+), 7 deletions(-)
> >
> > diff --git a/libavcodec/flicvideo.c b/libavcodec/flicvideo.c
> > index ba5bda48c4..cd9cd089af 100644
> > --- a/libavcodec/flicvideo.c
> > +++ b/libavcodec/flicvideo.c
> > @@ -175,7 +175,7 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
> >      int lines;
> >      int compressed_lines;
> >      int starting_line;
> > -    signed short line_packets;
> > +    int line_packets;
> >      int y_ptr;
> >      int byte_run;
> >      int pixel_skip;
> > @@ -274,7 +274,7 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
> >                      break;
> >                  if (y_ptr > pixel_limit)
> >                      return AVERROR_INVALIDDATA;
> > -                line_packets = bytestream2_get_le16(&g2);
> > +                line_packets = (int16_t)bytestream2_get_le16(&g2);
> >                  if ((line_packets & 0xC000) == 0xC000) {
> >                      // line skip opcode
> >                      line_packets = -line_packets;
> > @@ -340,7 +340,7 @@ static int flic_decode_frame_8BPP(AVCodecContext *avctx,
> >                  pixel_countdown = s->avctx->width;
> >                  if (bytestream2_tell(&g2) + 1 > stream_ptr_after_chunk)
> >                      break;
> > -                line_packets = bytestream2_get_byte(&g2);
> > +                line_packets = (int16_t)bytestream2_get_byte(&g2);
> >                  if (line_packets > 0) {
> >                      for (i = 0; i < line_packets; i++) {
> >                          /* account for the skip bytes */
> > @@ -508,7 +508,7 @@ static int flic_decode_frame_15_16BPP(AVCodecContext
> > *avctx,
> >
> >      int lines;
> >      int compressed_lines;
> > -    signed short line_packets;
> > +    int line_packets;
> >      int y_ptr;
> >      int byte_run;
> >      int pixel_skip;
> > @@ -572,7 +572,7 @@ static int flic_decode_frame_15_16BPP(AVCodecContext
> > *avctx,
> >                      break;
> >                  if (y_ptr > pixel_limit)
> >                      return AVERROR_INVALIDDATA;
> > -                line_packets = bytestream2_get_le16(&g2);
> > +                line_packets = (int16_t)bytestream2_get_le16(&g2);
> >                  if (line_packets < 0) {
> >                      line_packets = -line_packets;
> >                      if (line_packets > s->avctx->height)
> > @@ -806,7 +806,7 @@ static int flic_decode_frame_24BPP(AVCodecContext
> > *avctx,
> >
> >      int lines;
> >      int compressed_lines;
> > -    signed short line_packets;
> > +    int line_packets;
> >      int y_ptr;
> >      int byte_run;
> >      int pixel_skip;
> > @@ -870,7 +870,7 @@ static int flic_decode_frame_24BPP(AVCodecContext
> > *avctx,
> >                      break;
> >                  if (y_ptr > pixel_limit)
> >                      return AVERROR_INVALIDDATA;
> > -                line_packets = bytestream2_get_le16(&g2);
> > +                line_packets = (int16_t)bytestream2_get_le16(&g2);
> >                  if (line_packets < 0) {
> >                      line_packets = -line_packets;
> >                      if (line_packets > s->avctx->height)
> > --
> > 2.22.0
> >
> > _______________________________________________
> > 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".
> 
> In some cases casting in not needed.

unneeded one dropped


> Also cant you use sign_extend ?

certainly but that might be slower.
Do you prefer if i use sign_extend ?

thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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