[FFmpeg-devel] [PATCH 1/3] avcodec/qdm2: Do not read out of array in fix_coding_method_array()

[Michael Niedermayer]

Instead we ask for a sample, its unclear what to do in this case.

Fixes: index 30 out of bounds for type 'int8_t [30][64]'
Fixes: 15339/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QDM2_fuzzer-5749441484554240

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/qdm2.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/qdm2.c b/libavcodec/qdm2.c
index 1397218bdd..52c7cc73a0 100644
--- a/libavcodec/qdm2.c
+++ b/libavcodec/qdm2.c
@@ -408,6 +408,10 @@ static int fix_coding_method_array(int sb, int channels,
             }
             for (k = 0; k < run; k++) {
                 if (j + k < 128) {
+                    if (sb + (j + k) / 64 > 29) {
+                        SAMPLES_NEEDED
+                        continue;
+                    }
                     if (coding_method[ch][sb + (j + k) / 64][(j + k) % 64] > coding_method[ch][sb][j]) {
                         if (k > 0) {
                             SAMPLES_NEEDED
-- 
2.22.0