ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Aug 26 01:26:58 2017 +0200| [7ec414892ddcad88313848494b6fc5f437c9ca4a] | committer: Michael Niedermayer
avformat/hls: Fix DoS due to infinite loop
Fixes: loop.m3u
The default max iteration count of 1000 is arbitrary and ideas for a better solution are welcome
Found-by: Xiaohei and Wangchu from Alibaba Security Team
Previous version reviewed-by: Steven Liu <lingjiujianke at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7ec414892ddcad88313848494b6fc5f437c9ca4a
---
doc/demuxers.texi | 18 ++++++++++++++++++
libavformat/hls.c | 7 +++++++
2 files changed, 25 insertions(+)
diff --git a/doc/demuxers.texi b/doc/demuxers.texi
index 29a23d48b2..73dc0feec1 100644
--- a/doc/demuxers.texi
+++ b/doc/demuxers.texi
@@ -300,6 +300,24 @@ used to end the output video at the length of the shortest input file,
which in this case is @file{input.mp4} as the GIF in this example loops
infinitely.
+ at section hls
+
+HLS demuxer
+
+It accepts the following options:
+
+ at table @option
+ at item live_start_index
+segment index to start live streams at (negative values are from the end).
+
+ at item allowed_extensions
+',' separated list of file extensions that hls is allowed to access.
+
+ at item max_reload
+Maximum number of times a insufficient list is attempted to be reloaded.
+Default value is 1000.
+ at end table
+
@section image2
Image file demuxer.
diff --git a/libavformat/hls.c b/libavformat/hls.c
index 01731bd36b..0995345bbf 100644
--- a/libavformat/hls.c
+++ b/libavformat/hls.c
@@ -205,6 +205,7 @@ typedef struct HLSContext {
AVDictionary *avio_opts;
int strict_std_compliance;
char *allowed_extensions;
+ int max_reload;
} HLSContext;
static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
@@ -1263,6 +1264,7 @@ static int read_data(void *opaque, uint8_t *buf, int buf_size)
HLSContext *c = v->parent->priv_data;
int ret, i;
int just_opened = 0;
+ int reload_count = 0;
restart:
if (!v->needed)
@@ -1294,6 +1296,9 @@ restart:
reload_interval = default_reload_interval(v);
reload:
+ reload_count++;
+ if (reload_count > c->max_reload)
+ return AVERROR_EOF;
if (!v->finished &&
av_gettime_relative() - v->last_load_time >= reload_interval) {
if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) {
@@ -2150,6 +2155,8 @@ static const AVOption hls_options[] = {
OFFSET(allowed_extensions), AV_OPT_TYPE_STRING,
{.str = "3gp,aac,avi,flac,mkv,m3u8,m4a,m4s,m4v,mpg,mov,mp2,mp3,mp4,mpeg,mpegts,ogg,ogv,oga,ts,vob,wav"},
INT_MIN, INT_MAX, FLAGS},
+ {"max_reload", "Maximum number of times a insufficient list is attempted to be reloaded",
+ OFFSET(max_reload), AV_OPT_TYPE_INT, {.i64 = 1000}, 0, INT_MAX, FLAGS},
{NULL}
};