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| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-03-04 19:53:47 +0100 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-03-08 18:35:27 +0100 |
| commit | 568af6de058cb2b0c5b98d98ffcf37cdc6bc38a7 (patch) | |
| tree | 000dfbb55d053468114e829260c06b0f2e5f8298 | |
| parent | 8e05ba7f848475bdc3aa546cf88418f7e51a6671 (diff) | |
| download | blackbird-obmc-linux-568af6de058cb2b0c5b98d98ffcf37cdc6bc38a7.tar.gz blackbird-obmc-linux-568af6de058cb2b0c5b98d98ffcf37cdc6bc38a7.zip | |
netfilter: nf_tables: set pktinfo->thoff at AH header if found
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@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | include/net/netfilter/nf_tables_ipv6.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/net/netfilter/nf_tables_ipv6.h b/include/net/netfilter/nf_tables_ipv6.h index d150b5066201..97983d1c05e4 100644 --- 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 *pkt, 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 nft_pktinfo *pkt, 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 nft_pktinfo *pkt, 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; |
