5.10-stable review patch. If anyone has any objections, please let me know.
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From: Phil Sutter phil@nwl.cc
[ Upstream commit cf6b5ffdce5a78b2fcb0e53b3a2487c490bcbf7f ]
While iterating through an SCTP packet's chunks, skb_header_pointer() is called for the minimum expected chunk header size. If (that part of) the skbuff is non-linear, the following memcpy() may read data past temporary buffer '_sch'. Use skb_copy_bits() instead which does the right thing in this situation.
Fixes: 133dc203d77df ("netfilter: nft_exthdr: Support SCTP chunks") Suggested-by: Florian Westphal fw@strlen.de Signed-off-by: Phil Sutter phil@nwl.cc Reviewed-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nft_exthdr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index 274c5f0085186..eb183c024ac46 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -389,7 +389,9 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr, break;
dest[priv->len / NFT_REG32_SIZE] = 0; - memcpy(dest, (char *)sch + priv->offset, priv->len); + if (skb_copy_bits(pkt->skb, offset + priv->offset, + dest, priv->len) < 0) + break; return; } offset += SCTP_PAD4(ntohs(sch->length));