The socket lookup helpers are also needed for fixing xt_cgroups, therefore refactor them into shareable helper functions. This simplifies and optimizes the xt_socket code itself a bit as well, i.e. time to verdict for early demux sockets should be much faster than previously: We've unnecessarily extracted proto, {s,d}addr and {s,d}ports from the skb data, accessing possible conntrack information, etc even though we were not even calling into the socket lookup via xt_socket_get_sock_v4() due to skb->sk hit. After this patch, we only proceed the slow-path when we have an actual skb->sk miss. Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Cc: Daniel Mack <daniel@xxxxxxxxxx> Cc: Florian Westphal <fw@xxxxxxxxx> --- net/netfilter/xt_sk_helper.h | 282 +++++++++++++++++++++++++++++++++++++++++ net/netfilter/xt_socket.c | 293 +++---------------------------------------- 2 files changed, 300 insertions(+), 275 deletions(-) create mode 100644 net/netfilter/xt_sk_helper.h diff --git a/net/netfilter/xt_sk_helper.h b/net/netfilter/xt_sk_helper.h new file mode 100644 index 0000000..604b7ac --- /dev/null +++ b/net/netfilter/xt_sk_helper.h @@ -0,0 +1,282 @@ +/* + * Transparent proxy support for Linux/iptables + * + * Copyright (C) 2007-2008 BalaBit IT Ltd. + * Author: Krisztian Kovacs + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/skbuff.h> + +#include <net/tcp.h> +#include <net/udp.h> +#include <net/icmp.h> +#include <net/sock.h> + +#include <net/netfilter/ipv4/nf_defrag_ipv4.h> + +#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) +#define XT_HAVE_IPV6 1 +#include <linux/netfilter_ipv6/ip6_tables.h> +#include <net/inet6_hashtables.h> +#include <net/netfilter/ipv6/nf_defrag_ipv6.h> +#endif + +#if IS_ENABLED(CONFIG_NF_CONNTRACK) +#define XT_HAVE_CONNTRACK 1 +#include <net/netfilter/nf_conntrack.h> +#endif + +static int extract_icmp4_fields(const struct sk_buff *skb, u8 *protocol, + __be32 *raddr, __be32 *laddr, __be16 *rport, + __be16 *lport) +{ + unsigned int outside_hdrlen = ip_hdrlen(skb); + struct iphdr *inside_iph, _inside_iph; + struct icmphdr *icmph, _icmph; + __be16 *ports, _ports[2]; + + icmph = skb_header_pointer(skb, outside_hdrlen, + sizeof(_icmph), &_icmph); + if (icmph == NULL) + return 1; + + switch (icmph->type) { + case ICMP_DEST_UNREACH: + case ICMP_SOURCE_QUENCH: + case ICMP_REDIRECT: + case ICMP_TIME_EXCEEDED: + case ICMP_PARAMETERPROB: + break; + default: + return 1; + } + + inside_iph = skb_header_pointer(skb, outside_hdrlen + + sizeof(struct icmphdr), + sizeof(_inside_iph), &_inside_iph); + if (inside_iph == NULL) + return 1; + + if (inside_iph->protocol != IPPROTO_TCP && + inside_iph->protocol != IPPROTO_UDP) + return 1; + + ports = skb_header_pointer(skb, outside_hdrlen + + sizeof(struct icmphdr) + + (inside_iph->ihl << 2), + sizeof(_ports), &_ports); + if (ports == NULL) + return 1; + + /* The inside IP packet is the one quoted from our side, thus + * its saddr is the local address. + */ + + *protocol = inside_iph->protocol; + *laddr = inside_iph->saddr; + *lport = ports[0]; + *raddr = inside_iph->daddr; + *rport = ports[1]; + + return 0; +} + +static struct sock *xt_get_sk_v4(struct net *net, const u8 protocol, + const __be32 saddr, const __be32 daddr, + const __be16 sport, const __be16 dport, + const struct net_device *in) +{ + switch (protocol) { + case IPPROTO_TCP: + return __inet_lookup(net, &tcp_hashinfo, + saddr, sport, daddr, dport, + in->ifindex); + case IPPROTO_UDP: + return udp4_lib_lookup(net, saddr, sport, daddr, dport, + in->ifindex); + } + + return NULL; +} + +static struct sock *xt_sk_lookup(const struct sk_buff *skb, + const struct net_device *indev) +{ + const struct iphdr *iph = ip_hdr(skb); + __be32 uninitialized_var(daddr), uninitialized_var(saddr); + __be16 uninitialized_var(dport), uninitialized_var(sport); + u8 uninitialized_var(protocol); +#ifdef XT_HAVE_CONNTRACK + struct nf_conn const *ct; + enum ip_conntrack_info ctinfo; +#endif + + if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) { + struct udphdr _hdr, *hp = NULL; + + hp = skb_header_pointer(skb, ip_hdrlen(skb), + sizeof(_hdr), &_hdr); + if (hp == NULL) + return NULL; + + protocol = iph->protocol; + + saddr = iph->saddr; + daddr = iph->daddr; + + sport = hp->source; + dport = hp->dest; + + } else if (iph->protocol == IPPROTO_ICMP) { + if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr, + &sport, &dport)) + return NULL; + } else { + return NULL; + } + +#ifdef XT_HAVE_CONNTRACK + /* Do the lookup with the original socket address in + * case this is a reply packet of an established + * SNAT-ted connection. + */ + ct = nf_ct_get(skb, &ctinfo); + if (ct && !nf_ct_is_untracked(ct) && + ((iph->protocol != IPPROTO_ICMP && + ctinfo == IP_CT_ESTABLISHED_REPLY) || + (iph->protocol == IPPROTO_ICMP && + ctinfo == IP_CT_RELATED_REPLY)) && + (ct->status & IPS_SRC_NAT_DONE)) { + + daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip; + dport = (iph->protocol == IPPROTO_TCP) ? + ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port : + ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; + } +#endif + return xt_get_sk_v4(dev_net(skb->dev), protocol, saddr, daddr, + sport, dport, indev); +} + +#ifdef XT_HAVE_IPV6 +static int extract_icmp6_fields(const struct sk_buff *skb, + unsigned int outside_hdrlen, + int *protocol, + const struct in6_addr **raddr, + const struct in6_addr **laddr, + __be16 *rport, __be16 *lport, + struct ipv6hdr *ipv6_var) +{ + const struct ipv6hdr *inside_iph; + struct icmp6hdr *icmph, _icmph; + __be16 *ports, _ports[2]; + u8 inside_nexthdr; + __be16 inside_fragoff; + int inside_hdrlen; + + icmph = skb_header_pointer(skb, outside_hdrlen, + sizeof(_icmph), &_icmph); + if (icmph == NULL) + return 1; + + if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK) + return 1; + + inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), + sizeof(*ipv6_var), ipv6_var); + if (inside_iph == NULL) + return 1; + + inside_nexthdr = inside_iph->nexthdr; + inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + + sizeof(*ipv6_var), + &inside_nexthdr, &inside_fragoff); + if (inside_hdrlen < 0) + return 1; /* hjm: Packet has no/incomplete transport layer headers. */ + + if (inside_nexthdr != IPPROTO_TCP && + inside_nexthdr != IPPROTO_UDP) + return 1; + + ports = skb_header_pointer(skb, inside_hdrlen, + sizeof(_ports), &_ports); + if (ports == NULL) + return 1; + + /* The inside IP packet is the one quoted from our side, thus + * its saddr is the local address. + */ + + *protocol = inside_nexthdr; + *laddr = &inside_iph->saddr; + *lport = ports[0]; + *raddr = &inside_iph->daddr; + *rport = ports[1]; + + return 0; +} + +static struct sock *xt_get_sk_v6(struct net *net, const u8 protocol, + const struct in6_addr *saddr, + const struct in6_addr *daddr, + const __be16 sport, const __be16 dport, + const struct net_device *in) +{ + switch (protocol) { + case IPPROTO_TCP: + return inet6_lookup(net, &tcp_hashinfo, + saddr, sport, daddr, dport, + in->ifindex); + case IPPROTO_UDP: + return udp6_lib_lookup(net, saddr, sport, daddr, dport, + in->ifindex); + } + + return NULL; +} + +static struct sock *xt_sk_lookup6(const struct sk_buff *skb, + const struct net_device *indev) +{ + __be16 uninitialized_var(dport), uninitialized_var(sport); + const struct in6_addr *daddr = NULL, *saddr = NULL; + struct ipv6hdr *iph = ipv6_hdr(skb); + int thoff = 0, tproto; + + tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL); + if (tproto < 0) { + pr_debug("unable to find transport header in IPv6 packet, dropping\n"); + return NULL; + } + + if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) { + struct udphdr _hdr, *hp; + + hp = skb_header_pointer(skb, thoff, sizeof(_hdr), &_hdr); + if (hp == NULL) + return NULL; + + saddr = &iph->saddr; + daddr = &iph->daddr; + + sport = hp->source; + dport = hp->dest; + + } else if (tproto == IPPROTO_ICMPV6) { + struct ipv6hdr ipv6_var; + + if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr, + &sport, &dport, &ipv6_var)) + return NULL; + } else { + return NULL; + } + + return xt_get_sk_v6(dev_net(skb->dev), tproto, saddr, daddr, + sport, dport, indev); +} +#endif /* XT_HAVE_IPV6 */ diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c index 895534e..570ae6e 100644 --- a/net/netfilter/xt_socket.c +++ b/net/netfilter/xt_socket.c @@ -7,90 +7,18 @@ * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. - * */ + #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/module.h> #include <linux/skbuff.h> -#include <linux/netfilter/x_tables.h> -#include <linux/netfilter_ipv4/ip_tables.h> -#include <net/tcp.h> -#include <net/udp.h> -#include <net/icmp.h> -#include <net/sock.h> -#include <net/inet_sock.h> -#include <net/netfilter/ipv4/nf_defrag_ipv4.h> - -#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) -#define XT_SOCKET_HAVE_IPV6 1 -#include <linux/netfilter_ipv6/ip6_tables.h> -#include <net/inet6_hashtables.h> -#include <net/netfilter/ipv6/nf_defrag_ipv6.h> -#endif +#include <linux/netfilter/x_tables.h> #include <linux/netfilter/xt_socket.h> +#include <linux/netfilter_ipv4/ip_tables.h> -#if IS_ENABLED(CONFIG_NF_CONNTRACK) -#define XT_SOCKET_HAVE_CONNTRACK 1 -#include <net/netfilter/nf_conntrack.h> -#endif - -static int -extract_icmp4_fields(const struct sk_buff *skb, - u8 *protocol, - __be32 *raddr, - __be32 *laddr, - __be16 *rport, - __be16 *lport) -{ - unsigned int outside_hdrlen = ip_hdrlen(skb); - struct iphdr *inside_iph, _inside_iph; - struct icmphdr *icmph, _icmph; - __be16 *ports, _ports[2]; - - icmph = skb_header_pointer(skb, outside_hdrlen, - sizeof(_icmph), &_icmph); - if (icmph == NULL) - return 1; - - switch (icmph->type) { - case ICMP_DEST_UNREACH: - case ICMP_SOURCE_QUENCH: - case ICMP_REDIRECT: - case ICMP_TIME_EXCEEDED: - case ICMP_PARAMETERPROB: - break; - default: - return 1; - } - - inside_iph = skb_header_pointer(skb, outside_hdrlen + - sizeof(struct icmphdr), - sizeof(_inside_iph), &_inside_iph); - if (inside_iph == NULL) - return 1; - - if (inside_iph->protocol != IPPROTO_TCP && - inside_iph->protocol != IPPROTO_UDP) - return 1; - - ports = skb_header_pointer(skb, outside_hdrlen + - sizeof(struct icmphdr) + - (inside_iph->ihl << 2), - sizeof(_ports), &_ports); - if (ports == NULL) - return 1; - - /* the inside IP packet is the one quoted from our side, thus - * its saddr is the local address */ - *protocol = inside_iph->protocol; - *laddr = inside_iph->saddr; - *lport = ports[0]; - *raddr = inside_iph->daddr; - *rport = ports[1]; - - return 0; -} +#include "xt_sk_helper.h" /* "socket" match based redirection (no specific rule) * =================================================== @@ -111,23 +39,6 @@ extract_icmp4_fields(const struct sk_buff *skb, * then local services could intercept traffic going through the * box. */ -static struct sock * -xt_socket_get_sock_v4(struct net *net, const u8 protocol, - const __be32 saddr, const __be32 daddr, - const __be16 sport, const __be16 dport, - const struct net_device *in) -{ - switch (protocol) { - case IPPROTO_TCP: - return __inet_lookup(net, &tcp_hashinfo, - saddr, sport, daddr, dport, - in->ifindex); - case IPPROTO_UDP: - return udp4_lib_lookup(net, saddr, sport, daddr, dport, - in->ifindex); - } - return NULL; -} static bool xt_socket_sk_is_transparent(struct sock *sk) { @@ -147,63 +58,13 @@ static bool socket_match(const struct sk_buff *skb, struct xt_action_param *par, const struct xt_socket_mtinfo1 *info) { - const struct iphdr *iph = ip_hdr(skb); - struct udphdr _hdr, *hp = NULL; struct sock *sk = skb->sk; - __be32 uninitialized_var(daddr), uninitialized_var(saddr); - __be16 uninitialized_var(dport), uninitialized_var(sport); - u8 uninitialized_var(protocol); -#ifdef XT_SOCKET_HAVE_CONNTRACK - struct nf_conn const *ct; - enum ip_conntrack_info ctinfo; -#endif - - if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) { - hp = skb_header_pointer(skb, ip_hdrlen(skb), - sizeof(_hdr), &_hdr); - if (hp == NULL) - return false; - - protocol = iph->protocol; - saddr = iph->saddr; - sport = hp->source; - daddr = iph->daddr; - dport = hp->dest; - - } else if (iph->protocol == IPPROTO_ICMP) { - if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr, - &sport, &dport)) - return false; - } else { - return false; - } - -#ifdef XT_SOCKET_HAVE_CONNTRACK - /* Do the lookup with the original socket address in case this is a - * reply packet of an established SNAT-ted connection. */ - - ct = nf_ct_get(skb, &ctinfo); - if (ct && !nf_ct_is_untracked(ct) && - ((iph->protocol != IPPROTO_ICMP && - ctinfo == IP_CT_ESTABLISHED_REPLY) || - (iph->protocol == IPPROTO_ICMP && - ctinfo == IP_CT_RELATED_REPLY)) && - (ct->status & IPS_SRC_NAT_DONE)) { - - daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip; - dport = (iph->protocol == IPPROTO_TCP) ? - ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port : - ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; - } -#endif if (!sk) - sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol, - saddr, daddr, sport, dport, - par->in); + sk = xt_sk_lookup(skb, par->in); if (sk) { - bool wildcard; bool transparent = true; + bool wildcard; /* Ignore sockets listening on INADDR_ANY, * unless XT_SOCKET_NOWILDCARD is set @@ -225,12 +86,7 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par, sk = NULL; } - pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n", - protocol, &saddr, ntohs(sport), - &daddr, ntohs(dport), - &iph->daddr, hp ? ntohs(hp->dest) : 0, sk); - - return (sk != NULL); + return sk != NULL; } static bool @@ -249,127 +105,18 @@ socket_mt4_v1_v2(const struct sk_buff *skb, struct xt_action_param *par) return socket_match(skb, par, par->matchinfo); } -#ifdef XT_SOCKET_HAVE_IPV6 - -static int -extract_icmp6_fields(const struct sk_buff *skb, - unsigned int outside_hdrlen, - int *protocol, - const struct in6_addr **raddr, - const struct in6_addr **laddr, - __be16 *rport, - __be16 *lport, - struct ipv6hdr *ipv6_var) -{ - const struct ipv6hdr *inside_iph; - struct icmp6hdr *icmph, _icmph; - __be16 *ports, _ports[2]; - u8 inside_nexthdr; - __be16 inside_fragoff; - int inside_hdrlen; - - icmph = skb_header_pointer(skb, outside_hdrlen, - sizeof(_icmph), &_icmph); - if (icmph == NULL) - return 1; - - if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK) - return 1; - - inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), - sizeof(*ipv6_var), ipv6_var); - if (inside_iph == NULL) - return 1; - inside_nexthdr = inside_iph->nexthdr; - - inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + - sizeof(*ipv6_var), - &inside_nexthdr, &inside_fragoff); - if (inside_hdrlen < 0) - return 1; /* hjm: Packet has no/incomplete transport layer headers. */ - - if (inside_nexthdr != IPPROTO_TCP && - inside_nexthdr != IPPROTO_UDP) - return 1; - - ports = skb_header_pointer(skb, inside_hdrlen, - sizeof(_ports), &_ports); - if (ports == NULL) - return 1; - - /* the inside IP packet is the one quoted from our side, thus - * its saddr is the local address */ - *protocol = inside_nexthdr; - *laddr = &inside_iph->saddr; - *lport = ports[0]; - *raddr = &inside_iph->daddr; - *rport = ports[1]; - - return 0; -} - -static struct sock * -xt_socket_get_sock_v6(struct net *net, const u8 protocol, - const struct in6_addr *saddr, const struct in6_addr *daddr, - const __be16 sport, const __be16 dport, - const struct net_device *in) -{ - switch (protocol) { - case IPPROTO_TCP: - return inet6_lookup(net, &tcp_hashinfo, - saddr, sport, daddr, dport, - in->ifindex); - case IPPROTO_UDP: - return udp6_lib_lookup(net, saddr, sport, daddr, dport, - in->ifindex); - } - - return NULL; -} - +#ifdef XT_HAVE_IPV6 static bool socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par) { - struct ipv6hdr ipv6_var, *iph = ipv6_hdr(skb); - struct udphdr _hdr, *hp = NULL; - struct sock *sk = skb->sk; - const struct in6_addr *daddr = NULL, *saddr = NULL; - __be16 uninitialized_var(dport), uninitialized_var(sport); - int thoff = 0, uninitialized_var(tproto); const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo; - - tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL); - if (tproto < 0) { - pr_debug("unable to find transport header in IPv6 packet, dropping\n"); - return NF_DROP; - } - - if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) { - hp = skb_header_pointer(skb, thoff, - sizeof(_hdr), &_hdr); - if (hp == NULL) - return false; - - saddr = &iph->saddr; - sport = hp->source; - daddr = &iph->daddr; - dport = hp->dest; - - } else if (tproto == IPPROTO_ICMPV6) { - if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr, - &sport, &dport, &ipv6_var)) - return false; - } else { - return false; - } + struct sock *sk = skb->sk; if (!sk) - sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto, - saddr, daddr, sport, dport, - par->in); + sk = xt_sk_lookup6(skb, par->in); if (sk) { - bool wildcard; bool transparent = true; + bool wildcard; /* Ignore sockets listening on INADDR_ANY * unless XT_SOCKET_NOWILDCARD is set @@ -391,13 +138,7 @@ socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par) sk = NULL; } - pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu " - "(orig %pI6:%hu) sock %p\n", - tproto, saddr, ntohs(sport), - daddr, ntohs(dport), - &iph->daddr, hp ? ntohs(hp->dest) : 0, sk); - - return (sk != NULL); + return sk != NULL; } #endif @@ -409,6 +150,7 @@ static int socket_mt_v1_check(const struct xt_mtchk_param *par) pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V1); return -EINVAL; } + return 0; } @@ -420,6 +162,7 @@ static int socket_mt_v2_check(const struct xt_mtchk_param *par) pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V2); return -EINVAL; } + return 0; } @@ -444,7 +187,7 @@ static struct xt_match socket_mt_reg[] __read_mostly = { (1 << NF_INET_LOCAL_IN), .me = THIS_MODULE, }, -#ifdef XT_SOCKET_HAVE_IPV6 +#ifdef XT_HAVE_IPV6 { .name = "socket", .revision = 1, @@ -468,7 +211,7 @@ static struct xt_match socket_mt_reg[] __read_mostly = { (1 << NF_INET_LOCAL_IN), .me = THIS_MODULE, }, -#ifdef XT_SOCKET_HAVE_IPV6 +#ifdef XT_HAVE_IPV6 { .name = "socket", .revision = 2, @@ -486,7 +229,7 @@ static struct xt_match socket_mt_reg[] __read_mostly = { static int __init socket_mt_init(void) { nf_defrag_ipv4_enable(); -#ifdef XT_SOCKET_HAVE_IPV6 +#ifdef XT_HAVE_IPV6 nf_defrag_ipv6_enable(); #endif -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html