[FFmpeg-cvslog] avcodec/bonk: Use unsigned in predictor_calc_error() to avoid undefined overflows

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Nov  5 20:03:52 2022 +0100| [f4df49eb483fc49026a8d5578983376347d8e532] | committer: Michael Niedermayer

avcodec/bonk: Use unsigned in predictor_calc_error() to avoid undefined overflows

Fixes: signed integer overflow: 22 * -2107998208 cannot be represented in type 'int'
Fixes: 51363/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_BONK_fuzzer-5660734784143360

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f4df49eb483fc49026a8d5578983376347d8e532
---

 libavcodec/bonk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/bonk.c b/libavcodec/bonk.c
index 409694f710..c3ad80ec73 100644
--- a/libavcodec/bonk.c
+++ b/libavcodec/bonk.c
@@ -273,7 +273,7 @@ static int predictor_calc_error(int *k, int *state, int order, int error)
         *state_ptr = &(state[order-2]);
 
     for (i = order-2; i >= 0; i--, k_ptr--, state_ptr--) {
-        int k_value = *k_ptr, state_value = *state_ptr;
+        unsigned k_value = *k_ptr, state_value = *state_ptr;
 
         x -= shift_down(k_value * state_value, LATTICE_SHIFT);
         state_ptr[1] = state_value + shift_down(k_value * x, LATTICE_SHIFT);