netfilter: nft_exthdr: Search chunks in SCTP packets only
[ Upstream commit 5acc44f39458f43dac9724cefa4da29847cfe997 ] Since user space does not generate a payload dependency, plain sctp chunk matches cause searching in non-SCTP packets, too. Avoid this potential mis-interpretation of packet data by checking pkt->tprot. Fixes: 133dc203d77df ("netfilter: nft_exthdr: Support SCTP chunks") Signed-off-by: Phil Sutter <phil@nwl.cc> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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@ -371,6 +371,9 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
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const struct sctp_chunkhdr *sch;
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struct sctp_chunkhdr _sch;
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if (pkt->tprot != IPPROTO_SCTP)
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goto err;
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do {
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sch = skb_header_pointer(pkt->skb, offset, sizeof(_sch), &_sch);
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if (!sch || !sch->length)
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@ -391,7 +394,7 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr,
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}
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offset += SCTP_PAD4(ntohs(sch->length));
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} while (offset < pkt->skb->len);
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err:
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if (priv->flags & NFT_EXTHDR_F_PRESENT)
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nft_reg_store8(dest, false);
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else
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