From 5acc44f39458f43dac9724cefa4da29847cfe997 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 11 Jun 2021 19:06:45 +0200 Subject: netfilter: nft_exthdr: Search chunks in SCTP packets only 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 Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_exthdr.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/netfilter/nft_exthdr.c') diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index 7f705b5c09de..9cf86be2cff4 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -312,6 +312,9 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr, const struct sctp_chunkhdr *sch; struct sctp_chunkhdr _sch; + if (pkt->tprot != IPPROTO_SCTP) + goto err; + do { sch = skb_header_pointer(pkt->skb, offset, sizeof(_sch), &_sch); if (!sch || !sch->length) @@ -334,7 +337,7 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr, } offset += SCTP_PAD4(ntohs(sch->length)); } while (offset < pkt->skb->len); - +err: if (priv->flags & NFT_EXTHDR_F_PRESENT) nft_reg_store8(dest, false); else -- cgit