[FFmpeg-cvslog] avformat/dsicin: Check packet size for overflow

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Fri Apr 23 19:44:08 2021 +0200| [a09127eacd33596b8e18974e639082f170828d2e] | committer: Michael Niedermayer

avformat/dsicin: Check packet size for overflow

Fixes: signed integer overflow: 24672 + 2147483424 cannot be represented in type 'int'
Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_DSICIN_fuzzer-6731325979623424

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 9d1c47ec033d038e04578eaf0767c8983250d03d)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a09127eacd33596b8e18974e639082f170828d2e
---

 libavformat/dsicin.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libavformat/dsicin.c b/libavformat/dsicin.c
index b18f43b9a0..5a1f256595 100644
--- a/libavformat/dsicin.c
+++ b/libavformat/dsicin.c
@@ -166,7 +166,8 @@ static int cin_read_packet(AVFormatContext *s, AVPacket *pkt)
     CinDemuxContext *cin = s->priv_data;
     AVIOContext *pb = s->pb;
     CinFrameHeader *hdr = &cin->frame_header;
-    int rc, palette_type, pkt_size;
+    int rc, palette_type;
+    int64_t pkt_size;
     int ret;
 
     if (cin->audio_buffer_size == 0) {
@@ -182,7 +183,9 @@ static int cin_read_packet(AVFormatContext *s, AVPacket *pkt)
         }
 
         /* palette and video packet */
-        pkt_size = (palette_type + 3) * hdr->pal_colors_count + hdr->video_frame_size;
+        pkt_size = (palette_type + 3LL) * hdr->pal_colors_count + hdr->video_frame_size;
+        if (pkt_size + 4 > INT_MAX)
+            return AVERROR_INVALIDDATA;
 
         pkt_size = ffio_limit(pb, pkt_size);