From: Florian Westphal <fw@xxxxxxxxx> Quoting https://bugzilla.netfilter.org/show_bug.cgi?id=812: [ ip6tables -m addrtype ] When I tried to use in the nat/PREROUTING it messes up the routing cache even if the rule didn't matched at all. [..] If I remove the --limit-iface-in from the non-working scenario, so just use the -m addrtype --dst-type LOCAL it works! This happens when LOCAL type matching is requested with --limit-iface-in, and the default ipv6 route is via the interface the packet we test arrived on. Because xt_addrtype uses ip6_route_output, the ipv6 routing implementation creates an unwanted cached entry, and the packet won't make it to the real/expected destination. Silently ignoring --limit-iface-in makes the routing work but it breaks rule matching (--dst-type LOCAL with limit-iface-in is supposed to only match if the dst address is configured on the incoming interface; without --limit-iface-in it will match if the address is reachable via lo). The test should call ipv6_chk_addr() instead. However, this would add a link-time dependency on ipv6. There are two possible solutions: 1) Revert the commit that moved ipt_addrtype to xt_addrtype, and put ipv6 specific code into ip6t_addrtype. 2) add new "nf_ipv6_ops" struct to register pointers to ipv6 functions. While the former might seem preferable, Pablo pointed out that there are more xt modules with link-time dependeny issues regarding ipv6, so lets go for 2). Signed-off-by: Florian Westphal <fw@xxxxxxxxx> Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> --- include/linux/netfilter_ipv6.h | 16 ++++++++++++++++ include/net/addrconf.h | 2 +- net/ipv6/addrconf.c | 2 +- net/ipv6/netfilter.c | 7 +++++++ net/netfilter/core.c | 2 ++ net/netfilter/xt_addrtype.c | 27 ++++++++++++++++----------- 6 files changed, 43 insertions(+), 13 deletions(-) diff --git a/include/linux/netfilter_ipv6.h b/include/linux/netfilter_ipv6.h index 98ffb54..2d4df6ce 100644 --- a/include/linux/netfilter_ipv6.h +++ b/include/linux/netfilter_ipv6.h @@ -17,6 +17,22 @@ extern __sum16 nf_ip6_checksum(struct sk_buff *skb, unsigned int hook, extern int ipv6_netfilter_init(void); extern void ipv6_netfilter_fini(void); + +/* + * Hook functions for ipv6 to allow xt_* modules to be built-in even + * if IPv6 is a module. + */ +struct nf_ipv6_ops { + int (*chk_addr)(struct net *net, const struct in6_addr *addr, + const struct net_device *dev, int strict); +}; + +extern const struct nf_ipv6_ops __rcu *nf_ipv6_ops; +static inline const struct nf_ipv6_ops *nf_get_ipv6_ops(void) +{ + return rcu_dereference(nf_ipv6_ops); +} + #else /* CONFIG_NETFILTER */ static inline int ipv6_netfilter_init(void) { return 0; } static inline void ipv6_netfilter_fini(void) { return; } diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 84a6440..21f70270 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -65,7 +65,7 @@ extern int addrconf_set_dstaddr(struct net *net, extern int ipv6_chk_addr(struct net *net, const struct in6_addr *addr, - struct net_device *dev, + const struct net_device *dev, int strict); #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index d1ab6ab..d1b2d80 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1487,7 +1487,7 @@ static int ipv6_count_addresses(struct inet6_dev *idev) } int ipv6_chk_addr(struct net *net, const struct in6_addr *addr, - struct net_device *dev, int strict) + const struct net_device *dev, int strict) { struct inet6_ifaddr *ifp; unsigned int hash = inet6_addr_hash(addr); diff --git a/net/ipv6/netfilter.c b/net/ipv6/netfilter.c index 72836f4..95f3f1d 100644 --- a/net/ipv6/netfilter.c +++ b/net/ipv6/netfilter.c @@ -10,6 +10,7 @@ #include <linux/netfilter.h> #include <linux/netfilter_ipv6.h> #include <linux/export.h> +#include <net/addrconf.h> #include <net/dst.h> #include <net/ipv6.h> #include <net/ip6_route.h> @@ -186,6 +187,10 @@ static __sum16 nf_ip6_checksum_partial(struct sk_buff *skb, unsigned int hook, return csum; }; +static const struct nf_ipv6_ops ipv6ops = { + .chk_addr = ipv6_chk_addr, +}; + static const struct nf_afinfo nf_ip6_afinfo = { .family = AF_INET6, .checksum = nf_ip6_checksum, @@ -198,6 +203,7 @@ static const struct nf_afinfo nf_ip6_afinfo = { int __init ipv6_netfilter_init(void) { + RCU_INIT_POINTER(nf_ipv6_ops, &ipv6ops); return nf_register_afinfo(&nf_ip6_afinfo); } @@ -206,5 +212,6 @@ int __init ipv6_netfilter_init(void) */ void ipv6_netfilter_fini(void) { + RCU_INIT_POINTER(nf_ipv6_ops, NULL); nf_unregister_afinfo(&nf_ip6_afinfo); } diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 07c865a..857ca9f 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -30,6 +30,8 @@ static DEFINE_MUTEX(afinfo_mutex); const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly; EXPORT_SYMBOL(nf_afinfo); +const struct nf_ipv6_ops __rcu *nf_ipv6_ops __read_mostly; +EXPORT_SYMBOL_GPL(nf_ipv6_ops); int nf_register_afinfo(const struct nf_afinfo *afinfo) { diff --git a/net/netfilter/xt_addrtype.c b/net/netfilter/xt_addrtype.c index 49c5ff7..68ff29f 100644 --- a/net/netfilter/xt_addrtype.c +++ b/net/netfilter/xt_addrtype.c @@ -22,6 +22,7 @@ #include <net/ip6_fib.h> #endif +#include <linux/netfilter_ipv6.h> #include <linux/netfilter/xt_addrtype.h> #include <linux/netfilter/x_tables.h> @@ -33,12 +34,12 @@ MODULE_ALIAS("ip6t_addrtype"); #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) static u32 match_lookup_rt6(struct net *net, const struct net_device *dev, - const struct in6_addr *addr) + const struct in6_addr *addr, u16 mask) { const struct nf_afinfo *afinfo; struct flowi6 flow; struct rt6_info *rt; - u32 ret; + u32 ret = 0; int route_err; memset(&flow, 0, sizeof(flow)); @@ -49,12 +50,19 @@ static u32 match_lookup_rt6(struct net *net, const struct net_device *dev, rcu_read_lock(); afinfo = nf_get_afinfo(NFPROTO_IPV6); - if (afinfo != NULL) + if (afinfo != NULL) { + const struct nf_ipv6_ops *v6ops; + + if (dev && (mask & XT_ADDRTYPE_LOCAL)) { + v6ops = nf_get_ipv6_ops(); + if (v6ops && v6ops->chk_addr(net, addr, dev, true)) + ret = XT_ADDRTYPE_LOCAL; + } route_err = afinfo->route(net, (struct dst_entry **)&rt, - flowi6_to_flowi(&flow), !!dev); - else + flowi6_to_flowi(&flow), false); + } else { route_err = 1; - + } rcu_read_unlock(); if (route_err) @@ -62,15 +70,12 @@ static u32 match_lookup_rt6(struct net *net, const struct net_device *dev, if (rt->rt6i_flags & RTF_REJECT) ret = XT_ADDRTYPE_UNREACHABLE; - else - ret = 0; - if (rt->rt6i_flags & RTF_LOCAL) + if (dev == NULL && rt->rt6i_flags & RTF_LOCAL) ret |= XT_ADDRTYPE_LOCAL; if (rt->rt6i_flags & RTF_ANYCAST) ret |= XT_ADDRTYPE_ANYCAST; - dst_release(&rt->dst); return ret; } @@ -90,7 +95,7 @@ static bool match_type6(struct net *net, const struct net_device *dev, if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST | XT_ADDRTYPE_UNREACHABLE) & mask) - return !!(mask & match_lookup_rt6(net, dev, addr)); + return !!(mask & match_lookup_rt6(net, dev, addr, mask)); return true; } -- 1.7.10.4 -- 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
