From 64426fd69981bf7cbd8c5fc606d486c0f54bef6f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kacper=20Michaj=C5=82ow?= <kasper93@gmail.com>
Date: Thu, 27 Jun 2024 02:40:35 +0200
Subject: [PATCH] avcodec/parser: ensure input padding is zeroed
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Fixes use of uninitialized value, reported by MSAN.

Found by OSS-Fuzz.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>

Fixes: 70852/clusterfuzz-testcase-minimized-ffmpeg_IO_DEMUXER_fuzzer-5179190066872320
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 5dfc0cc84129758b4eab2acdc3e186c3116deacd)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/parser.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavcodec/parser.c b/libavcodec/parser.c
index a63f532c48..b12712fb8d 100644
--- a/libavcodec/parser.c
+++ b/libavcodec/parser.c
@@ -267,6 +267,7 @@ int ff_combine_frame(ParseContext *pc, int next,
         }
         pc->buffer = new_buffer;
         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
+        memset(&pc->buffer[pc->index + *buf_size], 0, AV_INPUT_BUFFER_PADDING_SIZE);
         pc->index += *buf_size;
         return -1;
     }