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authorJulian Anastasov <ja@ssi.bg>2011-06-18 07:53:59 +0000
committerGreg Kroah-Hartman <gregkh@suse.de>2011-07-08 23:15:38 -0700
commitb95484f930629da00b491fb63eff41788d194344 (patch)
tree1a31ceaeaa1badf1d2fc16818935e900eb06c0e1
parent9672388919350b5f188722ac608bdc32f9bc3c3d (diff)
netfilter: Fix ip_route_me_harder triggering ip_rt_bug
[ Upstream commit ed6e4ef836d425bc35e33bf20fcec95e68203afa ] Avoid creating input routes with ip_route_me_harder. It does not work for locally generated packets. Instead, restrict sockets to provide valid saddr for output route (or unicast saddr for transparent proxy). For other traffic allow saddr to be unicast or local but if callers forget to check saddr type use 0 for the output route. The resulting handling should be: - REJECT TCP: - in INPUT we can provide addr_type = RTN_LOCAL but better allow rejecting traffic delivered with local route (no IP address => use RTN_UNSPEC to allow also RTN_UNICAST). - FORWARD: RTN_UNSPEC => allow RTN_LOCAL/RTN_UNICAST saddr, add fix to ignore RTN_BROADCAST and RTN_MULTICAST - OUTPUT: RTN_UNSPEC - NAT, mangle, ip_queue, nf_ip_reroute: RTN_UNSPEC in LOCAL_OUT - IPVS: - use RTN_LOCAL in LOCAL_OUT and FORWARD after SNAT to restrict saddr to be local Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--net/ipv4/netfilter.c60
-rw-r--r--net/ipv4/netfilter/ipt_REJECT.c14
2 files changed, 26 insertions, 48 deletions
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 4614babdc45f..2e97e3ec1eb7 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -17,51 +17,35 @@ int ip_route_me_harder(struct sk_buff *skb, unsigned addr_type)
const struct iphdr *iph = ip_hdr(skb);
struct rtable *rt;
struct flowi4 fl4 = {};
- unsigned long orefdst;
+ __be32 saddr = iph->saddr;
+ __u8 flags = 0;
unsigned int hh_len;
- unsigned int type;
- type = inet_addr_type(net, iph->saddr);
- if (skb->sk && inet_sk(skb->sk)->transparent)
- type = RTN_LOCAL;
- if (addr_type == RTN_UNSPEC)
- addr_type = type;
+ if (!skb->sk && addr_type != RTN_LOCAL) {
+ if (addr_type == RTN_UNSPEC)
+ addr_type = inet_addr_type(net, saddr);
+ if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST)
+ flags |= FLOWI_FLAG_ANYSRC;
+ else
+ saddr = 0;
+ }
/* some non-standard hacks like ipt_REJECT.c:send_reset() can cause
* packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook.
*/
- if (addr_type == RTN_LOCAL) {
- fl4.daddr = iph->daddr;
- if (type == RTN_LOCAL)
- fl4.saddr = iph->saddr;
- fl4.flowi4_tos = RT_TOS(iph->tos);
- fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
- fl4.flowi4_mark = skb->mark;
- fl4.flowi4_flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0;
- rt = ip_route_output_key(net, &fl4);
- if (IS_ERR(rt))
- return -1;
-
- /* Drop old route. */
- skb_dst_drop(skb);
- skb_dst_set(skb, &rt->dst);
- } else {
- /* non-local src, find valid iif to satisfy
- * rp-filter when calling ip_route_input. */
- fl4.daddr = iph->saddr;
- rt = ip_route_output_key(net, &fl4);
- if (IS_ERR(rt))
- return -1;
+ fl4.daddr = iph->daddr;
+ fl4.saddr = saddr;
+ fl4.flowi4_tos = RT_TOS(iph->tos);
+ fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
+ fl4.flowi4_mark = skb->mark;
+ fl4.flowi4_flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : flags;
+ rt = ip_route_output_key(net, &fl4);
+ if (IS_ERR(rt))
+ return -1;
- orefdst = skb->_skb_refdst;
- if (ip_route_input(skb, iph->daddr, iph->saddr,
- RT_TOS(iph->tos), rt->dst.dev) != 0) {
- dst_release(&rt->dst);
- return -1;
- }
- dst_release(&rt->dst);
- refdst_drop(orefdst);
- }
+ /* Drop old route. */
+ skb_dst_drop(skb);
+ skb_dst_set(skb, &rt->dst);
if (skb_dst(skb)->error)
return -1;
diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c
index 1ff79e557f96..51f13f8ec724 100644
--- a/net/ipv4/netfilter/ipt_REJECT.c
+++ b/net/ipv4/netfilter/ipt_REJECT.c
@@ -40,7 +40,6 @@ static void send_reset(struct sk_buff *oldskb, int hook)
struct iphdr *niph;
const struct tcphdr *oth;
struct tcphdr _otcph, *tcph;
- unsigned int addr_type;
/* IP header checks: fragment. */
if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
@@ -55,6 +54,9 @@ static void send_reset(struct sk_buff *oldskb, int hook)
if (oth->rst)
return;
+ if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
+ return;
+
/* Check checksum */
if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
return;
@@ -101,19 +103,11 @@ static void send_reset(struct sk_buff *oldskb, int hook)
nskb->csum_start = (unsigned char *)tcph - nskb->head;
nskb->csum_offset = offsetof(struct tcphdr, check);
- addr_type = RTN_UNSPEC;
- if (hook != NF_INET_FORWARD
-#ifdef CONFIG_BRIDGE_NETFILTER
- || (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
-#endif
- )
- addr_type = RTN_LOCAL;
-
/* ip_route_me_harder expects skb->dst to be set */
skb_dst_set_noref(nskb, skb_dst(oldskb));
nskb->protocol = htons(ETH_P_IP);
- if (ip_route_me_harder(nskb, addr_type))
+ if (ip_route_me_harder(nskb, RTN_UNSPEC))
goto free_nskb;
niph->ttl = ip4_dst_hoplimit(skb_dst(nskb));