[FFmpeg-devel] [PATCH 2/5] avcodec/alsdec: Fix integer overflow of raw_samples in decode_blocks()

[Michael Niedermayer]

Fixes: signed integer overflow: 2147483424 - -1772303236 cannot be represented in type 'int'
Fixes: 15708/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5067890362941440

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/alsdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index 6b5774175b..ac3eca42c7 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -1175,10 +1175,10 @@ static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
                 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair.\n");
 
             for (s = 0; s < div_blocks[b]; s++)
-                bd[0].raw_samples[s] = bd[1].raw_samples[s] - bd[0].raw_samples[s];
+                bd[0].raw_samples[s] = bd[1].raw_samples[s] - (unsigned)bd[0].raw_samples[s];
         } else if (bd[1].js_blocks) {
             for (s = 0; s < div_blocks[b]; s++)
-                bd[1].raw_samples[s] = bd[1].raw_samples[s] + bd[0].raw_samples[s];
+                bd[1].raw_samples[s] = bd[1].raw_samples[s] + (unsigned)bd[0].raw_samples[s];
         }
 
         offset  += div_blocks[b];
-- 
2.22.0