diff options
| author | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-10-17 13:03:29 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-10-25 13:48:41 +0200 |
| commit | c247897d7c194e6fb4a7c8314af2226bec017a59 (patch) | |
| tree | 6d7820dc41282cde1c9e261449aca619af41b82d /net/netfilter/nft_payload.c | |
| parent | d037abc2414b4539401e0e6aa278bedc4628ad69 (diff) | |
netfilter: nft_payload: access GRE payload via inner offset
Parse GRE v0 packets to properly set up inner offset, this allow for
matching on inner headers.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/nft_payload.c')
| -rw-r--r-- | net/netfilter/nft_payload.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 07621d509a68..03a1f271bf4f 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -19,6 +19,7 @@ /* For layer 4 checksum field offset. */ #include <linux/tcp.h> #include <linux/udp.h> +#include <net/gre.h> #include <linux/icmpv6.h> #include <linux/ip.h> #include <linux/ipv6.h> @@ -100,6 +101,37 @@ static int __nft_payload_inner_offset(struct nft_pktinfo *pkt) pkt->inneroff = thoff + __tcp_hdrlen(th); } break; + case IPPROTO_GRE: { + u32 offset = sizeof(struct gre_base_hdr), version; + struct gre_base_hdr *gre, _gre; + + gre = skb_header_pointer(pkt->skb, thoff, sizeof(_gre), &_gre); + if (!gre) + return -1; + + version = gre->flags & GRE_VERSION; + switch (version) { + case GRE_VERSION_0: + if (gre->flags & GRE_ROUTING) + return -1; + + if (gre->flags & GRE_CSUM) { + offset += sizeof_field(struct gre_full_hdr, csum) + + sizeof_field(struct gre_full_hdr, reserved1); + } + if (gre->flags & GRE_KEY) + offset += sizeof_field(struct gre_full_hdr, key); + + if (gre->flags & GRE_SEQ) + offset += sizeof_field(struct gre_full_hdr, seq); + break; + default: + return -1; + } + + pkt->inneroff = thoff + offset; + } + break; default: return -1; } |