[FFmpeg-cvslog] avformat/movenc: Check pal_size before use

[Michael Niedermayer]

ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Sat May 29 09:22:27 2021 +0200| [5f9f6894970b1c3e4157e695b9d1d7cd08f04be2] | committer: Michael Niedermayer

avformat/movenc: Check pal_size before use

Fixes: assertion failure
Fixes: out of array read
Fixes: Ticket8190
Fixes: CVE-2020-22015

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 4c1afa292520329eecd1cc7631bc59a8cca95c46)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5f9f6894970b1c3e4157e695b9d1d7cd08f04be2
---

 libavformat/movenc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index bd1e795a65..2cd5773dc5 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -2177,11 +2177,13 @@ static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
         avio_wb16(pb, 0x18); /* Reserved */
 
     if (track->mode == MODE_MOV && track->par->format == AV_PIX_FMT_PAL8) {
-        int pal_size = 1 << track->par->bits_per_coded_sample;
-        int i;
+        int pal_size, i;
         avio_wb16(pb, 0);             /* Color table ID */
         avio_wb32(pb, 0);             /* Color table seed */
         avio_wb16(pb, 0x8000);        /* Color table flags */
+        if (track->par->bits_per_coded_sample < 0 || track->par->bits_per_coded_sample > 8)
+            return AVERROR(EINVAL);
+        pal_size = 1 << track->par->bits_per_coded_sample;
         avio_wb16(pb, pal_size - 1);  /* Color table size (zero-relative) */
         for (i = 0; i < pal_size; i++) {
             uint32_t rgb = track->palette[i];