[FFmpeg-devel] [PATCH] avformat/scd: ensure SCD_MIN_HEADER_SIZE bytes are read

[FFmpeg-devel] [PATCH] avformat/scd: ensure SCD_MIN_HEADER_SIZE bytes are read

[Kacper Michajłow]

Instead of accessing unintialized data when input is shorter than
expected size.

Fixes use of uninitialized value in MSAN build.
Found by OSS-Fuzz.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
---
 libavformat/scd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libavformat/scd.c b/libavformat/scd.c
index ee118c1668..e57733a8d8 100644
--- a/libavformat/scd.c
+++ b/libavformat/scd.c
@@ -30,6 +30,7 @@
 #include "libavutil/mem.h"
 #include "libavformat/internal.h"
 #include "avformat.h"
+#include "avio_internal.h"
 #include "demux.h"
 
 #define SCD_MAGIC              ((uint64_t)MKBETAG('S', 'E', 'D', 'B') << 32 | \
@@ -243,7 +244,7 @@ static int scd_read_header(AVFormatContext *s)
     SCDDemuxContext *ctx = s->priv_data;
     uint8_t buf[SCD_MIN_HEADER_SIZE];
 
-    if ((ret = avio_read(s->pb, buf, SCD_MIN_HEADER_SIZE)) < 0)
+    if ((ret = ffio_read_size(s->pb, buf, SCD_MIN_HEADER_SIZE)) < 0)
         return ret;
 
     ctx->hdr.magic       = AV_RB64(buf +  0);
-- 
2.45.1

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Re: [FFmpeg-devel] [PATCH] avformat/scd: ensure SCD_MIN_HEADER_SIZE bytes are read

[Michael Niedermayer]

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On Mon, Jul 07, 2025 at 09:25:30PM +0200, Kacper Michajłow wrote:
> Instead of accessing unintialized data when input is shorter than
> expected size.
> 
> Fixes use of uninitialized value in MSAN build.
> Found by OSS-Fuzz.
> 
> Signed-off-by: Kacper Michajłow <kasper93@gmail.com>
> ---
>  libavformat/scd.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

will apply

thx

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 

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