[FFmpeg-devel] [PATCH] avformat: Add max_streams option

[Michael Niedermayer]

This allows user apps to stop OOM due to excessive number of streams
TODO: bump & docs

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavformat/avformat.h      | 7 +++++++
 libavformat/options_table.h | 1 +
 libavformat/utils.c         | 2 +-
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index f9f4d72..c81a916 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -1899,6 +1899,13 @@ typedef struct AVFormatContext {
      * - decoding: set by user through AVOptions (NO direct access)
      */
     char *protocol_blacklist;
+
+    /**
+     * The maximum number of streams.
+     * - encoding: unused
+     * - decoding: set by user through AVOptions (NO direct access)
+     */
+    int max_streams;
 } AVFormatContext;
 
 int av_format_get_probe_score(const AVFormatContext *s);
diff --git a/libavformat/options_table.h b/libavformat/options_table.h
index 9d61d5a..d5448e5 100644
--- a/libavformat/options_table.h
+++ b/libavformat/options_table.h
@@ -105,6 +105,7 @@ static const AVOption avformat_options[] = {
 {"format_whitelist", "List of demuxers that are allowed to be used", OFFSET(format_whitelist), AV_OPT_TYPE_STRING, { .str = NULL },  CHAR_MIN, CHAR_MAX, D },
 {"protocol_whitelist", "List of protocols that are allowed to be used", OFFSET(protocol_whitelist), AV_OPT_TYPE_STRING, { .str = NULL },  CHAR_MIN, CHAR_MAX, D },
 {"protocol_blacklist", "List of protocols that are not allowed to be used", OFFSET(protocol_blacklist), AV_OPT_TYPE_STRING, { .str = NULL },  CHAR_MIN, CHAR_MAX, D },
+{"max_streams", "maximum number of streams", OFFSET(max_streams), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 0, INT_MAX, D },
 {NULL},
 };
 
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 5664646..ded0b52 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -4210,7 +4210,7 @@ AVStream *avformat_new_stream(AVFormatContext *s, const AVCodec *c)
     int i;
     AVStream **streams;
 
-    if (s->nb_streams >= INT_MAX/sizeof(*streams))
+    if (s->nb_streams >= s->max_streams/sizeof(*streams))
         return NULL;
     streams = av_realloc_array(s->streams, s->nb_streams + 1, sizeof(*streams));
     if (!streams)
-- 
2.10.2