From c247897d7c194e6fb4a7c8314af2226bec017a59 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 17 Oct 2022 13:03:29 +0200 Subject: 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 --- net/netfilter/nft_payload.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'net/netfilter/nft_payload.c') 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 #include +#include #include #include #include @@ -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; } -- cgit v1.2.3