This is a note to let you know that I've just added the patch titled netfilter: nf_tables: set pktinfo->thoff at AH header if found to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: netfilter-nf_tables-set-pktinfo-thoff-at-ah-header-if-found.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Oct 5 10:28:31 CEST 2017 From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Date: Sat, 4 Mar 2017 19:53:47 +0100 Subject: netfilter: nf_tables: set pktinfo->thoff at AH header if found From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> [ Upstream commit 568af6de058cb2b0c5b98d98ffcf37cdc6bc38a7 ] Phil Sutter reports that IPv6 AH header matching is broken. From userspace, nft generates bytecode that expects to find the AH header at NFT_PAYLOAD_TRANSPORT_HEADER both for IPv4 and IPv6. However, pktinfo->thoff is set to the inner header after the AH header in IPv6, while in IPv4 pktinfo->thoff points to the AH header indeed. This behaviour is inconsistent. This patch fixes this problem by updating ipv6_find_hdr() to get the IP6_FH_F_AUTH flag so this function stops at the AH header, so both IPv4 and IPv6 pktinfo->thoff point to the AH header. This is also inconsistent when trying to match encapsulated headers: 1) A packet that looks like IPv4 + AH + TCP dport 22 will *not* match. 2) A packet that looks like IPv6 + AH + TCP dport 22 will match. Reported-by: Phil Sutter <phil@xxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/net/netfilter/nf_tables_ipv6.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/include/net/netfilter/nf_tables_ipv6.h +++ b/include/net/netfilter/nf_tables_ipv6.h @@ -9,12 +9,13 @@ nft_set_pktinfo_ipv6(struct nft_pktinfo struct sk_buff *skb, const struct nf_hook_state *state) { + unsigned int flags = IP6_FH_F_AUTH; int protohdr, thoff = 0; unsigned short frag_off; nft_set_pktinfo(pkt, skb, state); - protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL); + protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags); if (protohdr < 0) { nft_set_pktinfo_proto_unspec(pkt, skb); return; @@ -32,6 +33,7 @@ __nft_set_pktinfo_ipv6_validate(struct n const struct nf_hook_state *state) { #if IS_ENABLED(CONFIG_IPV6) + unsigned int flags = IP6_FH_F_AUTH; struct ipv6hdr *ip6h, _ip6h; unsigned int thoff = 0; unsigned short frag_off; @@ -50,7 +52,7 @@ __nft_set_pktinfo_ipv6_validate(struct n if (pkt_len + sizeof(*ip6h) > skb->len) return -1; - protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, NULL); + protohdr = ipv6_find_hdr(pkt->skb, &thoff, -1, &frag_off, &flags); if (protohdr < 0) return -1; Patches currently in stable-queue which might be from pablo@xxxxxxxxxxxxx are queue-4.9/netfilter-invoke-synchronize_rcu-after-set-the-_hook_-to-null.patch queue-4.9/netfilter-nfnl_cthelper-fix-incorrect-helper-expect_class_max.patch queue-4.9/netfilter-nf_tables-set-pktinfo-thoff-at-ah-header-if-found.patch