[FFmpeg-devel] [PATCH] avcodec/aacps: Check border_position to be monotone

[Michael Niedermayer]

Fixes: runtime error: left shift of negative value -67108864
Fixes: 1738/clusterfuzz-testcase-minimized-6734814327603200

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/aacps.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/aacps.c b/libavcodec/aacps.c
index 48b595adbd..31e072dd49 100644
--- a/libavcodec/aacps.c
+++ b/libavcodec/aacps.c
@@ -196,8 +196,13 @@ int AAC_RENAME(ff_ps_read_data)(AVCodecContext *avctx, GetBitContext *gb_host, P
 
     ps->border_position[0] = -1;
     if (ps->frame_class) {
-        for (e = 1; e <= ps->num_env; e++)
+        for (e = 1; e <= ps->num_env; e++) {
             ps->border_position[e] = get_bits(gb, 5);
+            if (ps->border_position[e] < ps->border_position[e-1]) {
+                av_log(avctx, AV_LOG_ERROR, "border_position non monotone.\n");
+                goto err;
+            }
+        }
     } else
         for (e = 1; e <= ps->num_env; e++)
             ps->border_position[e] = (e * numQMFSlots >> ff_log2_tab[ps->num_env]) - 1;
-- 
2.13.0