[FFmpeg-cvslog] avformat/id3v2: Check taglen in read_uslt()

[Michael Niedermayer]

ffmpeg | branch: release/3.4 | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov 18 19:04:47 2022 +0100| [76d48fbd867e206a26d9c312bf428378394b39ec] | committer: Michael Niedermayer

avformat/id3v2: Check taglen in read_uslt()

Fixes: Timeout (read mostly the same data repeatly)
Fixes: 52457/clusterfuzz-testcase-minimized-ffmpeg_dem_ALP_fuzzer-6610706313379840
Fixes: 53098/clusterfuzz-testcase-minimized-ffmpeg_dem_SOL_fuzzer-6481382981632000

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit a798af91d7d1fc31cfc1ae09cc6ab3907304f44f)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=76d48fbd867e206a26d9c312bf428378394b39ec
---

 libavformat/id3v2.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/id3v2.c b/libavformat/id3v2.c
index a1ef29ab01..a38cb5a6db 100644
--- a/libavformat/id3v2.c
+++ b/libavformat/id3v2.c
@@ -375,10 +375,10 @@ static void read_uslt(AVFormatContext *s, AVIOContext *pb, int taglen,
     lang[3] = '\0';
     taglen -= 3;
 
-    if (decode_str(s, pb, encoding, &descriptor, &taglen) < 0)
+    if (decode_str(s, pb, encoding, &descriptor, &taglen) < 0 || taglen < 0)
         goto error;
 
-    if (decode_str(s, pb, encoding, &text, &taglen) < 0)
+    if (decode_str(s, pb, encoding, &text, &taglen) < 0 || taglen < 0)
         goto error;
 
     // FFmpeg does not support hierarchical metadata, so concatenate the keys.