[FFmpeg-devel] [PATCH] lavc/cbs_h2645: Fix incorrect max size of nalu unit

[Andriy Gelman]

From: Andriy Gelman <andriy.gelman at gmail.com>

In the worst case the startcode prefix has 4 bytes.

This fixes a trigerred assertion:
Assertion dp <= max_size failed at libavcodec/cbs_h2645.c:1451

Found-by:libFuzzer
Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>
---
 libavcodec/cbs_h2645.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index 88fa0029cd6..5f71d805848 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -1395,7 +1395,7 @@ static int cbs_h2645_assemble_fragment(CodedBitstreamContext *ctx,
     max_size = 0;
     for (i = 0; i < frag->nb_units; i++) {
         // Start code + content with worst-case emulation prevention.
-        max_size += 3 + frag->units[i].data_size * 3 / 2;
+        max_size += 4 + frag->units[i].data_size * 3 / 2;
     }
 
     data = av_realloc(NULL, max_size + AV_INPUT_BUFFER_PADDING_SIZE);
-- 
2.24.0