[FFmpeg-devel] [PATCH] avformat/hls: Limit start_seq_no to one bit less

[FFmpeg-devel] [PATCH] avformat/hls: Limit start_seq_no to one bit less

[Michael Niedermayer]

This avoids overflow checks on additions with 32bit numbers

Fixes: signed integer overflow: 9223372036854775806 + 2 cannot be represented in type 'long'
Fixes: 44012/clusterfuzz-testcase-minimized-ffmpeg_dem_HLS_fuzzer-4747770734444544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavformat/hls.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavformat/hls.c b/libavformat/hls.c
index 8204f55df3..b736f093a9 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -837,10 +837,10 @@ static int parse_playlist(HLSContext *c, const char *url,
             if (ret < 0)
                 goto fail;
             seq_no = strtoull(ptr, NULL, 10);
-            if (seq_no > INT64_MAX) {
+            if (seq_no > INT64_MAX/2) {
                 av_log(c->ctx, AV_LOG_DEBUG, "MEDIA-SEQUENCE higher than "
-                        "INT64_MAX, mask out the highest bit\n");
-                seq_no &= INT64_MAX;
+                        "INT64_MAX/2, mask out the highest bit\n");
+                seq_no &= INT64_MAX/2;
             }
             pls->start_seq_no = seq_no;
         } else if (av_strstart(line, "#EXT-X-PLAYLIST-TYPE:", &ptr)) {
-- 
2.17.1

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH] avformat/hls: Limit start_seq_no to one bit less

[Michael Niedermayer]

[-- Attachment #1.1: Type: text/plain, Size: 918 bytes --]

On Fri, Jun 17, 2022 at 01:15:22AM +0200, Michael Niedermayer wrote:
> This avoids overflow checks on additions with 32bit numbers
> 
> Fixes: signed integer overflow: 9223372036854775806 + 2 cannot be represented in type 'long'
> Fixes: 44012/clusterfuzz-testcase-minimized-ffmpeg_dem_HLS_fuzzer-4747770734444544
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavformat/hls.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

will apply

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

Frequently ignored answer#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

[-- Attachment #2: Type: text/plain, Size: 251 bytes --]

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".