[FFmpeg-cvslog] libavformat/asfdec: Fix regression bug when reading image attachments

[softworkz]

ffmpeg | branch: master | softworkz <softworkz at hotmail.com> | Sun Apr 20 01:18:09 2025 +0200| [26429eee22d6b2ccb9b45747975b34806398a33c] | committer: softworkz

libavformat/asfdec: Fix regression bug when reading image attachments

Commit c8140fe7324f264faacf7395b27e12531d1f13f7 had introduced
a check for value_len > UINT16_MAX.
As a consequence, attached images of sizes larger than UINT16_MAX
could no longer be read.

This is a minimal fix of the regression, avoiding the controversies
of my earlier submission regarding int type handling in asfdec.

Signed-off-by: softworkz <softworkz at hotmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=26429eee22d6b2ccb9b45747975b34806398a33c
---

 libavformat/asfdec_f.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index 2441cadb44..ea6e8ef4f3 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -608,7 +608,8 @@ static int asf_read_metadata(AVFormatContext *s)
 {
     AVIOContext *pb = s->pb;
     ASFContext *asf = s->priv_data;
-    int n, stream_num, name_len_utf16, name_len_utf8, value_len;
+    int n, stream_num, name_len_utf16, name_len_utf8;
+    unsigned int value_len;
     int ret, i;
     n = avio_rl16(pb);
 
@@ -622,7 +623,7 @@ static int asf_read_metadata(AVFormatContext *s)
         value_type = avio_rl16(pb); /* value_type */
         value_len  = avio_rl32(pb);
 
-        if (value_len < 0 || value_len > UINT16_MAX)
+        if (value_len >= (INT_MAX - LEN) / 2)
             return AVERROR_INVALIDDATA;
 
         name_len_utf8 = 2*name_len_utf16 + 1;