avformat/imx: Check palette chunk size

Fixes: out of array write
Fixes: 32116/clusterfuzz-testcase-minimized-ffmpeg_dem_SIMBIOSIS_IMX_fuzzer-6702533894602752
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

diff --git a/libavformat/imx.c b/libavformat/imx.c
index d203ed7a2800c4b901dbda8bdc7740596be46a76..22fca0bdc0e0dab881665d1c1a19959a7994b6b9 100644 (file)
--- a/libavformat/imx.c
+++ b/libavformat/imx.c
@@ -113,6 +113,8 @@ retry:
             imx->first_video_packet_pos = pos;
         break;
     case 0xAA98:
+        if (chunk_size > 256 * 3)
+            return AVERROR_INVALIDDATA;
         for (int i = 0; i < chunk_size / 3; i++) {
             unsigned r = avio_r8(pb) << 18;
             unsigned g = avio_r8(pb) << 10;