[FFmpeg-cvslog] avcodec/pnmdec: Use unsigned for maxval rescaling

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Sat May 16 00:31:23 2020 +0200| [989a2788c094fc78e0fd209d691eae1c8ba8b2f4] | committer: Michael Niedermayer

avcodec/pnmdec: Use unsigned for maxval rescaling

Fixes: signed integer overflow: 65535 * 55335 cannot be represented in type 'int'
Fixes: 21955/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_PGMYUV_fuzzer-5669206981083136

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 49459aca47d4803b2188fbf12b758bd2b01e91d7)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=989a2788c094fc78e0fd209d691eae1c8ba8b2f4
---

 libavcodec/pnmdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/pnmdec.c b/libavcodec/pnmdec.c
index 958c5e43b0..2c98e26934 100644
--- a/libavcodec/pnmdec.c
+++ b/libavcodec/pnmdec.c
@@ -132,7 +132,7 @@ static int pnm_decode_frame(AVCodecContext *avctx, void *data,
                 init_put_bits(&pb, ptr, linesize);
                 for(j=0; j<avctx->width * components; j++){
                     unsigned int c=0;
-                    int v=0;
+                    unsigned v=0;
                     if(s->type < 4)
                     while(s->bytestream < s->bytestream_end && (*s->bytestream < '0' || *s->bytestream > '9' ))
                         s->bytestream++;