[PATCH net-next v3 30/33] xdp: clear grow memory in bpf_xdp_adjust_tail()
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STALE2363d
SUPERSEDED: 1 (0M)
From: Jesper Dangaard Brouer <hidden>
Date: 2020-05-08 11:11:34
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Status: Superseded by v4 (posted 2020-05-14). [go to v4]
Revision v3 (4 revisions archived); 1 review trailer.
Revisions (4)
- v2 re-posted go to this post
- v1 [diff against previous]
- v3 current [diff against previous]
- v4 [diff against previous]
Clearing memory of tail when grow happens, because it is too easy to write a XDP_PASS program that extend the tail, which expose this memory to users that can run tcpdump. Signed-off-by: Jesper Dangaard Brouer <redacted> Acked-by: Toke Høiland-Jørgensen <redacted> --- net/core/filter.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/net/core/filter.c b/net/core/filter.c
index ec3ab2e2d800..691235208e0b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -3427,6 +3427,10 @@ BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) if (unlikely(data_end < xdp->data + ETH_HLEN)) return -EINVAL; + /* Clear memory area on grow, can contain uninit kernel memory */ + if (offset > 0) + memset(xdp->data_end, 0, offset); + xdp->data_end = data_end; return 0;