From 2920c7cec0b1958b59e5e7990078bea4428f6912 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 26 Aug 2017 01:26:58 +0200 Subject: [PATCH] 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 Signed-off-by: Michael Niedermayer (cherry picked from commit 7ec414892ddcad88313848494b6fc5f437c9ca4a) Signed-off-by: Michael Niedermayer --- doc/demuxers.texi | 18 ++++++++++++++++++ libavformat/hls.c | 7 +++++++ 2 files changed, 25 insertions(+) diff --git doc/demuxers.texi doc/demuxers.texi index 2934a1cf7f4..d56ad1622a8 100644 --- external/FFmpeg/doc/demuxers.texi +++ external/FFmpeg/doc/demuxers.texi @@ -293,6 +293,24 @@ 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. +@section hls + +HLS demuxer + +It accepts the following options: + +@table @option +@item live_start_index +segment index to start live streams at (negative values are from the end). + +@item allowed_extensions +',' separated list of file extensions that hls is allowed to access. + +@item max_reload +Maximum number of times a insufficient list is attempted to be reloaded. +Default value is 1000. +@end table + @section image2 Image file demuxer. diff --git libavformat/hls.c libavformat/hls.c index ffefd284f86..87948726da6 100644 --- external/FFmpeg/libavformat/hls.c +++ external/FFmpeg/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) @@ -1255,6 +1256,7 @@ 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) @@ -1286,6 +1288,9 @@ static int read_data(void *opaque, uint8_t *buf, int buf_size) 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) { @@ -2143,6 +2148,8 @@ 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} };