[PATCH 27/47] netfilter: exthdr: factor out tcp option access
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2017-09-03 22:40:54
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> --- net/netfilter/nft_exthdr.c | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index 1ec49fe5845f..921c95f2c583 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c@@ -61,6 +61,26 @@ static void nft_exthdr_ipv6_eval(const struct nft_expr *expr, regs->verdict.code = NFT_BREAK; } +static void * +nft_tcp_header_pointer(const struct nft_pktinfo *pkt, + unsigned int len, void *buffer, unsigned int *tcphdr_len) +{ + struct tcphdr *tcph; + + if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP) + return NULL; + + tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buffer); + if (!tcph) + return NULL; + + *tcphdr_len = __tcp_hdrlen(tcph); + if (*tcphdr_len < sizeof(*tcph) || *tcphdr_len > len) + return NULL; + + return skb_header_pointer(pkt->skb, pkt->xt.thoff, *tcphdr_len, buffer); +} + static void nft_exthdr_tcp_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt)
@@ -72,18 +92,7 @@ static void nft_exthdr_tcp_eval(const struct nft_expr *expr, struct tcphdr *tcph; u8 *opt; - if (!pkt->tprot_set || pkt->tprot != IPPROTO_TCP) - goto err; - - tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, sizeof(*tcph), buff); - if (!tcph) - goto err; - - tcphdr_len = __tcp_hdrlen(tcph); - if (tcphdr_len < sizeof(*tcph)) - goto err; - - tcph = skb_header_pointer(pkt->skb, pkt->xt.thoff, tcphdr_len, buff); + tcph = nft_tcp_header_pointer(pkt, sizeof(buff), buff, &tcphdr_len); if (!tcph) goto err;
--
2.1.4