xfrm: make local error reporting more robust
In xfrm4 and xfrm6 we need to take care about sockets of the other
address family. This could happen because a 6in4 or 4in6 tunnel could
get protected by ipsec.
Because we don't want to have a run-time dependency on ipv6 when only
using ipv4 xfrm we have to embed a pointer to the correct local_error
function in xfrm_state_afinet and look it up when returning an error
depending on the socket address family.
Thanks to vi0ss for the great bug report:
<https://bugzilla.kernel.org/show_bug.cgi?id=58691>
v2:
a) fix two more unsafe interpretations of skb->sk as ipv6 socket
(xfrm6_local_dontfrag and __xfrm6_output)
v3:
a) add an EXPORT_SYMBOL_GPL(xfrm_local_error) to fix a link error when
building ipv6 as a module (thanks to Steffen Klassert)
Reported-by: <vi0oss@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index 327a617..7a5491f 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -33,8 +33,7 @@
mtu = dst_mtu(dst);
if (skb->len > mtu) {
if (skb->sk)
- ip_local_error(skb->sk, EMSGSIZE, ip_hdr(skb)->daddr,
- inet_sk(skb->sk)->inet_dport, mtu);
+ xfrm_local_error(skb, mtu);
else
icmp_send(skb, ICMP_DEST_UNREACH,
ICMP_FRAG_NEEDED, htonl(mtu));
@@ -99,3 +98,12 @@
x->outer_mode->afinfo->output_finish,
!(IPCB(skb)->flags & IPSKB_REROUTED));
}
+
+void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
+{
+ struct iphdr *hdr;
+
+ hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
+ ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
+ inet_sk(skb->sk)->inet_dport, mtu);
+}
diff --git a/net/ipv4/xfrm4_state.c b/net/ipv4/xfrm4_state.c
index 9258e75..0b2a064 100644
--- a/net/ipv4/xfrm4_state.c
+++ b/net/ipv4/xfrm4_state.c
@@ -83,6 +83,7 @@
.extract_input = xfrm4_extract_input,
.extract_output = xfrm4_extract_output,
.transport_finish = xfrm4_transport_finish,
+ .local_error = xfrm4_local_error,
};
void __init xfrm4_state_init(void)
diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 8755a30..b64fff3 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -34,8 +34,10 @@
struct sock *sk = skb->sk;
if (sk) {
- proto = sk->sk_protocol;
+ if (sk->sk_family != AF_INET6)
+ return 0;
+ proto = sk->sk_protocol;
if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
return inet6_sk(sk)->dontfrag;
}
@@ -54,7 +56,7 @@
ipv6_local_rxpmtu(sk, &fl6, mtu);
}
-static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
+void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
{
struct flowi6 fl6;
struct sock *sk = skb->sk;
@@ -80,7 +82,7 @@
if (xfrm6_local_dontfrag(skb))
xfrm6_local_rxpmtu(skb, mtu);
else if (skb->sk)
- xfrm6_local_error(skb, mtu);
+ xfrm_local_error(skb, mtu);
else
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ret = -EMSGSIZE;
@@ -142,7 +144,7 @@
xfrm6_local_rxpmtu(skb, mtu);
return -EMSGSIZE;
} else if (!skb->local_df && skb->len > mtu && skb->sk) {
- xfrm6_local_error(skb, mtu);
+ xfrm_local_error(skb, mtu);
return -EMSGSIZE;
}
diff --git a/net/ipv6/xfrm6_state.c b/net/ipv6/xfrm6_state.c
index d8c70b8..3fc9701 100644
--- a/net/ipv6/xfrm6_state.c
+++ b/net/ipv6/xfrm6_state.c
@@ -183,6 +183,7 @@
.extract_input = xfrm6_extract_input,
.extract_output = xfrm6_extract_output,
.transport_finish = xfrm6_transport_finish,
+ .local_error = xfrm6_local_error,
};
int __init xfrm6_state_init(void)
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index eb4a842..6f5fc61 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -214,5 +214,18 @@
return inner_mode->afinfo->extract_output(x, skb);
}
+void xfrm_local_error(struct sk_buff *skb, int mtu)
+{
+ struct xfrm_state_afinfo *afinfo;
+
+ afinfo = xfrm_state_get_afinfo(skb->sk->sk_family);
+ if (!afinfo)
+ return;
+
+ afinfo->local_error(skb, mtu);
+ xfrm_state_put_afinfo(afinfo);
+}
+
EXPORT_SYMBOL_GPL(xfrm_output);
EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
+EXPORT_SYMBOL_GPL(xfrm_local_error);
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index 78f66fa..54c0acd 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -39,9 +39,6 @@
static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024;
-static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
-static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);
-
static inline unsigned int xfrm_dst_hash(struct net *net,
const xfrm_address_t *daddr,
const xfrm_address_t *saddr,
@@ -1860,7 +1857,7 @@
}
EXPORT_SYMBOL(xfrm_state_unregister_afinfo);
-static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
+struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
{
struct xfrm_state_afinfo *afinfo;
if (unlikely(family >= NPROTO))
@@ -1872,7 +1869,7 @@
return afinfo;
}
-static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
+void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
{
rcu_read_unlock();
}