From 6ee0b693bdb8ec56689e0d1cc533b16466fda048 Mon Sep 17 00:00:00 2001 From: Changli Gao Date: Sun, 1 Apr 2012 17:25:06 +0000 Subject: [PATCH 1/5] netfilter: nf_ct_tcp: don't scale the size of the window up twice For a picked up connection, the window win is scaled twice: one is by the initialization code, and the other is by the sender updating code. I use the temporary variable swin instead of modifying the variable win. Signed-off-by: Changli Gao Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_proto_tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 361eade62a09..0d07a1dcf605 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -584,8 +584,8 @@ static bool tcp_in_window(const struct nf_conn *ct, * Let's try to use the data from the packet. */ sender->td_end = end; - win <<= sender->td_scale; - sender->td_maxwin = (win == 0 ? 1 : win); + swin = win << sender->td_scale; + sender->td_maxwin = (swin == 0 ? 1 : swin); sender->td_maxend = end + sender->td_maxwin; /* * We haven't seen traffic in the other direction yet From 95ad2f873d5d404dc9ebc2377de0b762346346c0 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 6 Apr 2012 18:12:54 +0200 Subject: [PATCH 2/5] netfilter: ip6_tables: ip6t_ext_hdr is now static inline We may hit this in xt_LOG: net/built-in.o:xt_LOG.c:function dump_ipv6_packet: error: undefined reference to 'ip6t_ext_hdr' happens with these config options: CONFIG_NETFILTER_XT_TARGET_LOG=y CONFIG_IP6_NF_IPTABLES=m ip6t_ext_hdr is fairly small and it is called in the packet path. Make it static inline. Reported-by: Simon Kirby Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_ipv6/ip6_tables.h | 12 +++++++++++- net/ipv6/netfilter/ip6_tables.c | 14 -------------- 2 files changed, 11 insertions(+), 15 deletions(-) diff --git a/include/linux/netfilter_ipv6/ip6_tables.h b/include/linux/netfilter_ipv6/ip6_tables.h index f549adccc94c..1bc898b14a80 100644 --- a/include/linux/netfilter_ipv6/ip6_tables.h +++ b/include/linux/netfilter_ipv6/ip6_tables.h @@ -287,7 +287,17 @@ extern unsigned int ip6t_do_table(struct sk_buff *skb, struct xt_table *table); /* Check for an extension */ -extern int ip6t_ext_hdr(u8 nexthdr); +static inline int +ip6t_ext_hdr(u8 nexthdr) +{ return (nexthdr == IPPROTO_HOPOPTS) || + (nexthdr == IPPROTO_ROUTING) || + (nexthdr == IPPROTO_FRAGMENT) || + (nexthdr == IPPROTO_ESP) || + (nexthdr == IPPROTO_AH) || + (nexthdr == IPPROTO_NONE) || + (nexthdr == IPPROTO_DSTOPTS); +} + /* find specified header and get offset to it */ extern int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, int target, unsigned short *fragoff); diff --git a/net/ipv6/netfilter/ip6_tables.c b/net/ipv6/netfilter/ip6_tables.c index 94874b0bdcdc..9d4e15559319 100644 --- a/net/ipv6/netfilter/ip6_tables.c +++ b/net/ipv6/netfilter/ip6_tables.c @@ -78,19 +78,6 @@ EXPORT_SYMBOL_GPL(ip6t_alloc_initial_table); Hence the start of any table is given by get_table() below. */ -/* Check for an extension */ -int -ip6t_ext_hdr(u8 nexthdr) -{ - return (nexthdr == IPPROTO_HOPOPTS) || - (nexthdr == IPPROTO_ROUTING) || - (nexthdr == IPPROTO_FRAGMENT) || - (nexthdr == IPPROTO_ESP) || - (nexthdr == IPPROTO_AH) || - (nexthdr == IPPROTO_NONE) || - (nexthdr == IPPROTO_DSTOPTS); -} - /* Returns whether matches rule or not. */ /* Performance critical - called for every packet */ static inline bool @@ -2366,7 +2353,6 @@ int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, EXPORT_SYMBOL(ip6t_register_table); EXPORT_SYMBOL(ip6t_unregister_table); EXPORT_SYMBOL(ip6t_do_table); -EXPORT_SYMBOL(ip6t_ext_hdr); EXPORT_SYMBOL(ipv6_find_hdr); module_init(ip6_tables_init); From 8430eac2f6a3c2adce22d490e2ab8bb50d59077a Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Mon, 9 Apr 2012 16:32:16 +0200 Subject: [PATCH 3/5] netfilter: nf_ct_ipv4: handle invalid IPv4 and IPv6 packets consistently IPv6 conntrack marked invalid packets as INVALID and let the user drop those by an explicit rule, while IPv4 conntrack dropped such packets itself. IPv4 conntrack is changed so that it marks INVALID packets and let the user to drop them. Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c index de9da21113a1..750b06afd20e 100644 --- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c +++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c @@ -74,12 +74,12 @@ static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); if (iph == NULL) - return -NF_DROP; + return -NF_ACCEPT; /* Conntrack defragments packets, we might still see fragments * inside ICMP packets though. */ if (iph->frag_off & htons(IP_OFFSET)) - return -NF_DROP; + return -NF_ACCEPT; *dataoff = nhoff + (iph->ihl << 2); *protonum = iph->protocol; From 07153c6ec074257ade76a461429b567cff2b3a1e Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Tue, 3 Apr 2012 22:02:01 +0200 Subject: [PATCH 4/5] netfilter: nf_ct_ipv4: packets with wrong ihl are invalid It was reported that the Linux kernel sometimes logs: klogd: [2629147.402413] kernel BUG at net / netfilter / nf_conntrack_proto_tcp.c: 447! klogd: [1072212.887368] kernel BUG at net / netfilter / nf_conntrack_proto_tcp.c: 392 ipv4_get_l4proto() in nf_conntrack_l3proto_ipv4.c and tcp_error() in nf_conntrack_proto_tcp.c should catch malformed packets, so the errors at the indicated lines - TCP options parsing - should not happen. However, tcp_error() relies on the "dataoff" offset to the TCP header, calculated by ipv4_get_l4proto(). But ipv4_get_l4proto() does not check bogus ihl values in IPv4 packets, which then can slip through tcp_error() and get caught at the TCP options parsing routines. The patch fixes ipv4_get_l4proto() by invalidating packets with bogus ihl value. The patch closes netfilter bugzilla id 771. Signed-off-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c index 750b06afd20e..cf73cc70ed2d 100644 --- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c +++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c @@ -84,6 +84,14 @@ static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, *dataoff = nhoff + (iph->ihl << 2); *protonum = iph->protocol; + /* Check bogus IP headers */ + if (*dataoff > skb->len) { + pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: " + "nhoff %u, ihl %u, skblen %u\n", + nhoff, iph->ihl << 2, skb->len); + return -NF_ACCEPT; + } + return NF_ACCEPT; } From 6ba900676bec8baaf61aa2f85b7345c0e65774d9 Mon Sep 17 00:00:00 2001 From: Gao feng Date: Sat, 7 Apr 2012 16:08:28 +0000 Subject: [PATCH 5/5] netfilter: nf_conntrack: fix incorrect logic in nf_conntrack_init_net in function nf_conntrack_init_net,when nf_conntrack_timeout_init falied, we should call nf_conntrack_ecache_fini to do rollback. but the current code calls nf_conntrack_timeout_fini. Signed-off-by: Gao feng Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 3cc4487ac349..729f157a0efa 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1592,7 +1592,7 @@ static int nf_conntrack_init_net(struct net *net) return 0; err_timeout: - nf_conntrack_timeout_fini(net); + nf_conntrack_ecache_fini(net); err_ecache: nf_conntrack_tstamp_fini(net); err_tstamp: