The hevc_mp4toannexb bsf does not explicitly check whether a NAL unit
is so big that it extends beyond the end of the input packet; it does so
only implicitly by using the checked version of the bytestream2 API.
But this has downsides compared to real checks: It can lead to huge
allocations (up to 2GiB) even when the input packet is just a few bytes.
And furthermore it leads to uninitialized data being output.
So add a check to error out early if it happens.
Also check directly whether there is enough data for the length field.
Signed-off-by: Andreas Rheinhardt
---
libavcodec/hevc_mp4toannexb_bsf.c | 6 +-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/libavcodec/hevc_mp4toannexb_bsf.c
b/libavcodec/hevc_mp4toannexb_bsf.c
index a880d9ba9a..ba1deb2848 100644
--- a/libavcodec/hevc_mp4toannexb_bsf.c
+++ b/libavcodec/hevc_mp4toannexb_bsf.c
@@ -142,10 +142,14 @@ static int hevc_mp4toannexb_filter(AVBSFContext *ctx,
AVPacket *out)
int nalu_type;
int is_irap, add_extradata, extra_size, prev_size;
+if (bytestream2_get_bytes_left(&gb) < s->length_size) {
+ret = AVERROR_INVALIDDATA;
+goto fail;
+}
for (i = 0; i < s->length_size; i++)
nalu_size = (nalu_size << 8) | bytestream2_get_byte(&gb);
-if (nalu_size < 2) {
+if (nalu_size < 2 || nalu_size > bytestream2_get_bytes_left(&gb)) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
--
2.20.1
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