avcodec/dpcm: clip exponent into supported range in XAN DPCM
Fixes: shift exponent 32 is too large for 32-bit type 'int'
Fixes: 21200/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_XAN_DPCM_fuzzer-5754704894361600
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Anton Khirnov <[email protected]>
Signed-off-by: Michael Niedermayer <[email protected]>
diff --git a/libavcodec/dpcm.c b/libavcodec/dpcm.c
index 069bf1d..7078419 100644
--- a/libavcodec/dpcm.c
+++ b/libavcodec/dpcm.c
@@ -321,9 +321,8 @@
shift[ch] -= (2 * n);
diff = sign_extend((diff &~ 3) << 8, 16);
- /* saturate the shifter to a lower limit of 0 */
- if (shift[ch] < 0)
- shift[ch] = 0;
+ /* saturate the shifter to 0..31 */
+ shift[ch] = av_clip_uintp2(shift[ch], 5);
diff >>= shift[ch];
predictor[ch] += diff;
