avcodec/adpcm: Check channels before use for ADPCM_PSX

Fixes: division by zero
Fixes: 26293/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_PSX_fuzzer-5176665237618688
Fixes: 26331/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_PSX_fuzzer-5632330364092416
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/libavcodec/adpcm.c b/libavcodec/adpcm.c
index f7da3dcf8980babf9aff83441cd04e6a9e36ca83..d018c1f91bbe012c3ae702ad6afa75dde4a073e4 100644 (file)
--- a/libavcodec/adpcm.c
+++ b/libavcodec/adpcm.c
@@ -135,7 +135,7 @@ static av_cold int adpcm_decode_init(AVCodecContext * avctx)
         break;
     case AV_CODEC_ID_ADPCM_PSX:
         max_channels = 8;
-        if (avctx->block_align % (16 * avctx->channels))
+        if (avctx->channels <= 0 || avctx->block_align % (16 * avctx->channels))
             return AVERROR_INVALIDDATA;
         break;
     case AV_CODEC_ID_ADPCM_IMA_DAT4: