Currently the API is internally limited to unsigned integers, so if we
limit the file size as well as the amount to read to UINT_MAX - 1, we
do not require additional limiting to be performed on the values.
This change is based on the fact that initially the 8*1024 value added
in 96d70694aea64616c68db8be306c159c73fb3980 was only for the case where
the file size was not known. It was not a maximum file size limit.
In 29121188983932f79aef8501652630d322a9974c this was reworked to be
a maximum manifest file size limit, while its commit message appears
to only note that it added support for larger manifest file sizes.
This should enable various unfortunately large MPEG-DASH manifests,
such as Youtube's multi-megabyte live stream archives to load up
as well as bring back the original intent of the logic.
---
libavformat/dashdec.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/libavformat/dashdec.c b/libavformat/dashdec.c
index c5a5ff607b..1e9985f32c 100644
--- a/libavformat/dashdec.c
+++ b/libavformat/dashdec.c
@@ -29,7 +29,7 @@
#include "dash.h"
#define INITIAL_BUFFER_SIZE 32768
-#define MAX_MANIFEST_SIZE 50 * 1024
+#define MAX_BPRINT_READ_SIZE (UINT_MAX - 1)
#define DEFAULT_MANIFEST_SIZE 8 * 1024
struct fragment {
@@ -1256,14 +1256,16 @@ static int parse_manifest(AVFormatContext *s, const
char *url, AVIOContext *in)
}
filesize = avio_size(in);
- if (filesize > MAX_MANIFEST_SIZE) {
+ filesize = filesize > 0 ? filesize : DEFAULT_MANIFEST_SIZE;
+
+ if (filesize > MAX_BPRINT_READ_SIZE) {
av_log(s, AV_LOG_ERROR, "Manifest too large: %"PRId64"\n", filesize);
return AVERROR_INVALIDDATA;
}
- av_bprint_init(&buf, (filesize > 0) ? filesize + 1 :
DEFAULT_MANIFEST_SIZE, AV_BPRINT_SIZE_UNLIMITED);
+ av_bprint_init(&buf, filesize + 1, AV_BPRINT_SIZE_UNLIMITED);
- if ((ret = avio_read_to_bprint(in, &buf, MAX_MANIFEST_SIZE)) < 0 ||
+ if ((ret = avio_read_to_bprint(in, &buf, MAX_BPRINT_READ_SIZE)) < 0 ||
!avio_feof(in) ||
(filesize = buf.len) == 0) {
av_log(s, AV_LOG_ERROR, "Unable to read to manifest '%s'\n", url);
--
2.26.2
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