[FFmpeg-devel] [PATCH] avformat/mxfdec: Don't pretend array to be bigger than it is

* [FFmpeg-devel] [PATCH] avformat/mxfdec: Don't pretend array to be bigger than it is
@ 2023-09-11 16:29 Andreas Rheinhardt
  2023-09-11 16:50 ` Tomas Härdin
  0 siblings, 1 reply; 2+ messages in thread
From: Andreas Rheinhardt @ 2023-09-11 16:29 UTC (permalink / raw)
  To: ffmpeg-devel; +Cc: Andreas Rheinhardt

mxf_match_uid() accepts two const UID and a len parameter.
UID is a typedef for an array of 16 uint8_t, so the const UID
parameter is actually a pointer to const uint8_t.

The point of mxf_match_uid() is to check whether the initial
part of two UIDs match; the length of said part is given
by the len parameter. Once an incomplete UID has been passed
to mxf_match_uid() (albeit with the correct len, so safe),
which makes GCC emit -Wstringop-overread warnings.

Fix this by using a const uint8_t[] as type; it is more
natural for incomplete UIDs.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavformat/mxfdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 7dbe294d23..4846c5d206 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -1544,11 +1544,11 @@ static int mxf_read_tagged_value(void *arg, AVIOContext *pb, int tag, int size,
  * Match an uid independently of the version byte and up to len common bytes
  * Returns: boolean
  */
-static int mxf_match_uid(const UID key, const UID uid, int len)
+static int mxf_match_uid(const UID key, const uint8_t uid_prefix[], int len)
 {
     int i;
     for (i = 0; i < len; i++) {
-        if (i != 7 && key[i] != uid[i])
+        if (i != 7 && key[i] != uid_prefix[i])
             return 0;
     }
     return 1;
-- 
2.34.1

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