From 628e341f319f1a64a4639088faba952e4ec8f0a8 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Wed, 14 Aug 2013 13:05:23 +0200 Subject: [PATCH] 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: 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: Cc: Steffen Klassert Signed-off-by: Hannes Frederic Sowa Signed-off-by: Steffen Klassert --- include/net/xfrm.h | 6 ++++++ net/ipv4/xfrm4_output.c | 12 ++++++++++-- net/ipv4/xfrm4_state.c | 1 + net/ipv6/xfrm6_output.c | 10 ++++++---- net/ipv6/xfrm6_state.c | 1 + net/xfrm/xfrm_output.c | 13 +++++++++++++ net/xfrm/xfrm_state.c | 7 ++----- 7 files changed, 39 insertions(+), 11 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 94ce082..e823786 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -341,10 +341,13 @@ struct xfrm_state_afinfo { struct sk_buff *skb); int (*transport_finish)(struct sk_buff *skb, int async); + void (*local_error)(struct sk_buff *skb, u32 mtu); }; extern int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo); extern int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo); +extern struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family); +extern void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo); extern void xfrm_state_delete_tunnel(struct xfrm_state *x); @@ -1477,6 +1480,7 @@ extern int xfrm_input_resume(struct sk_buff *skb, int nexthdr); extern int xfrm_output_resume(struct sk_buff *skb, int err); extern int xfrm_output(struct sk_buff *skb); extern int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb); +extern void xfrm_local_error(struct sk_buff *skb, int mtu); extern int xfrm4_extract_header(struct sk_buff *skb); extern int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb); extern int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi, @@ -1497,6 +1501,7 @@ extern int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short fam extern int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family); extern int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler); extern int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler); +extern void xfrm4_local_error(struct sk_buff *skb, u32 mtu); extern int xfrm6_extract_header(struct sk_buff *skb); extern int xfrm6_extract_input(struct xfrm_state *x, struct sk_buff *skb); extern int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi); @@ -1514,6 +1519,7 @@ extern int xfrm6_output(struct sk_buff *skb); extern int xfrm6_output_finish(struct sk_buff *skb); extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr); +extern void xfrm6_local_error(struct sk_buff *skb, u32 mtu); #ifdef CONFIG_XFRM extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb); 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 @@ static int xfrm4_tunnel_check_size(struct sk_buff *skb) 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 @@ int xfrm4_output(struct sk_buff *skb) 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 @@ static struct xfrm_state_afinfo xfrm4_state_afinfo = { .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 @@ static int xfrm6_local_dontfrag(struct sk_buff *skb) 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 @@ static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu) 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 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb) 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 @@ static int __xfrm6_output(struct sk_buff *skb) 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 @@ static struct xfrm_state_afinfo xfrm6_state_afinfo = { .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 @@ int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) 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 DEFINE_SPINLOCK(xfrm_state_lock); 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 @@ int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo) } 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 @@ static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family) 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(); } -- 2.7.4