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

[Kacper Michajłow]

ffmpeg | branch: master | Kacper Michajłow <kasper93 at gmail.com> | Mon Jul  7 21:25:30 2025 +0200| [3334bdc6e70dfdbf753fa81da0d8321a1c5c7eeb] | committer: Michael Niedermayer

avformat/scd: ensure SCD_MIN_HEADER_SIZE bytes are read

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 at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3334bdc6e70dfdbf753fa81da0d8321a1c5c7eeb
---

 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);