On 4/22/2024 5:40 PM, Mark Thompson wrote:
On 22/04/2024 02:31, Michael Niedermayer wrote:
Found-by-reviewing: CID1419833 Untrusted loop bound
Sponsored-by: Sovereign Tech Fund
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc>
---
libavcodec/cbs_h2645.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/libavcodec/cbs_h2645.c b/libavcodec/cbs_h2645.c
index fe2e383ff33..1a45d424bae 100644
--- a/libavcodec/cbs_h2645.c
+++ b/libavcodec/cbs_h2645.c
@@ -709,7 +709,11 @@ static int cbs_h2645_split_fragment(CodedBitstreamContext
*ctx,
start = bytestream2_tell(&gbc);
for(i = 0; i < num_nalus; i++) {
+ if (bytestream2_get_bytes_left(&gbc) < 2)
+ return AVERROR_INVALIDDATA;
size = bytestream2_get_be16(&gbc);
+ if (bytestream2_get_bytes_left(&gbc) < size)
+ return AVERROR_INVALIDDATA;
bytestream2_skip(&gbc, size);
}
end = bytestream2_tell(&gbc);
Seems fair.
The problem looks more general with missing bounds checks in all the H.266 code
around this, though? Compare with H.26[45], which have checks on all the reads
- seems like H.266 should be doing that.
Thanks,
Not against this approach, but since the bytestream2_get_* functions
return 0, never overread the buffer or move the internal pointer,
wouldn't it be enough to just ensure end > start?
Particularly in ff_h2645_packet_split(), we can return an error if
length (in this case being set to end - start) is < 4.
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