Re: [PATCH] [RFC] Support for wccp version 1 and 2 in ip_gre.c
From: "David S. Miller" <davem@davemloft.net>
Date: 2004-09-15 05:47:48
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On Tue, 14 Sep 2004 18:48:20 +1000 Lincoln Dale [off-list ref] wrote:
the logic is correct, but it may make sense to call the appropriate netfilter hook again with the "unwrapped" GRE packet, as otherwise packets-inside-GRE represent a possible security hole where one can inject packets externally and bypass firewall rules.
This will occur when we push the packet back into the RX path via the netif_rx() call. Paul if you want to fix up the comment, that's fine. But please send such a patch relative to what I put into the tree already which is the following: # This is a BitKeeper generated diff -Nru style patch. # # ChangeSet # 2004/09/13 16:04:36-07:00 i@stingr.net # [IPV4]: Add wccp v1/v2 support to ip_gre.c # # Signed-off-by: David S. Miller [off-list ref] # # net/ipv4/ip_gre.c # 2004/09/13 16:04:06-07:00 i@stingr.net +12 -1 # [IPV4]: Add wccp v1/v2 support to ip_gre.c # # include/linux/if_ether.h # 2004/09/13 16:04:06-07:00 i@stingr.net +2 -0 # [IPV4]: Add wccp v1/v2 support to ip_gre.c # diff -Nru a/include/linux/if_ether.h b/include/linux/if_ether.h
--- a/include/linux/if_ether.h 2004-09-14 22:27:39 -07:00
+++ b/include/linux/if_ether.h 2004-09-14 22:27:39 -07:00@@ -59,6 +59,8 @@ #define ETH_P_8021Q 0x8100 /* 802.1Q VLAN Extended Header */ #define ETH_P_IPX 0x8137 /* IPX over DIX */ #define ETH_P_IPV6 0x86DD /* IPv6 over bluebook */ +#define ETH_P_WCCP 0x883E /* Web-cache coordination protocol + * defined in draft-wilson-wrec-wccp-v2-00.txt */ #define ETH_P_PPP_DISC 0x8863 /* PPPoE discovery messages */ #define ETH_P_PPP_SES 0x8864 /* PPPoE session messages */ #define ETH_P_MPLS_UC 0x8847 /* MPLS Unicast traffic */
diff -Nru a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
--- a/net/ipv4/ip_gre.c 2004-09-14 22:27:39 -07:00
+++ b/net/ipv4/ip_gre.c 2004-09-14 22:27:39 -07:00@@ -603,13 +603,24 @@ if ((tunnel = ipgre_tunnel_lookup(iph->saddr, iph->daddr, key)) != NULL) { secpath_reset(skb); + skb->protocol = *(u16*)(h + 2); + /* WCCP version 1 and 2 protocol decoding. + * - Change protocol to IP + * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header + */ + if (flags == 0 && + skb->protocol == __constant_htons(ETH_P_WCCP)) { + skb->protocol = __constant_htons(ETH_P_IP); + if ((*(h + offset) & 0xF0) != 0x40) + offset += 4; + } + skb->mac.raw = skb->nh.raw; skb->nh.raw = __pskb_pull(skb, offset); memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options)); if (skb->ip_summed == CHECKSUM_HW) skb->csum = csum_sub(skb->csum, csum_partial(skb->mac.raw, skb->nh.raw-skb->mac.raw, 0)); - skb->protocol = *(u16*)(h + 2); skb->pkt_type = PACKET_HOST; #ifdef CONFIG_NET_IPGRE_BROADCAST if (MULTICAST(iph->daddr)) {