[FFmpeg-devel] [PATCH 1/2] avcodec/dirac_vlc: Fix invalid shift

[Michael Niedermayer]

Fixes: runtime error: shift exponent 65 is too large for 64-bit type 'residual' (aka 'unsigned long')
Fixes: 2737/clusterfuzz-testcase-minimized-4968639147016192

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/dirac_vlc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/dirac_vlc.c b/libavcodec/dirac_vlc.c
index 773f720858..f9a6017ec0 100644
--- a/libavcodec/dirac_vlc.c
+++ b/libavcodec/dirac_vlc.c
@@ -96,6 +96,9 @@ int ff_dirac_golomb_read_16bit(DiracGolombLUT *lut_ctx, const uint8_t *buf,
         if ((c_idx + 1) > coeffs)
             return c_idx;
 
+        if (res_bits >= RSIZE_BITS)
+            return 0;
+
         if (res_bits && l->sign) {
             int32_t coeff = 1;
             APPEND_RESIDUE(res, l->preamble);
-- 
2.13.0