[FFmpeg-devel] [PATCH 2/3] avcodec/shorten: Fix integer overflow with offset

[Michael Niedermayer]

Fixes: signed integer overflow: -1625810908 - 582229060 cannot be represented in type 'int'
Fixes: 10977/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SHORTEN_fuzzer-5732602018267136

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

diff --git a/libavcodec/shorten.c b/libavcodec/shorten.c
index 4b45e6d6dc..4134af74cf 100644
--- a/libavcodec/shorten.c
+++ b/libavcodec/shorten.c
@@ -382,7 +382,7 @@ static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
     /* subtract offset from previous samples to use in prediction */
     if (command == FN_QLPC && coffset)
         for (i = -pred_order; i < 0; i++)
-            s->decoded[channel][i] -= coffset;
+            s->decoded[channel][i] -= (unsigned)coffset;
 
     /* decode residual and do LPC prediction */
     init_sum = pred_order ? (command == FN_QLPC ? s->lpcqoffset : 0) : coffset;
@@ -397,7 +397,7 @@ static int decode_subframe_lpc(ShortenContext *s, int command, int channel,
     /* add offset to current samples */
     if (command == FN_QLPC && coffset)
         for (i = 0; i < s->blocksize; i++)
-            s->decoded[channel][i] += coffset;
+            s->decoded[channel][i] += (unsigned)coffset;
 
     return 0;
 }
-- 
2.19.1