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Commit 628e341f authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by Steffen Klassert
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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: default avatar <vi0oss@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
parent d9bf5f13

include/net/xfrm.h

+6 −0
Original line number Original line Diff line number Diff line
@@ -341,10 +341,13 @@ struct xfrm_state_afinfo { 
						  struct sk_buff *skb);

						  struct sk_buff *skb);

	int			(*transport_finish)(struct sk_buff *skb,

	int			(*transport_finish)(struct sk_buff *skb,

						    int async);

						    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_register_afinfo(struct xfrm_state_afinfo *afinfo);

extern int xfrm_state_unregister_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);

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_resume(struct sk_buff *skb, int err);

extern int xfrm_output(struct sk_buff *skb);

extern int xfrm_output(struct sk_buff *skb);

extern int xfrm_inner_extract_output(struct xfrm_state *x, 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_header(struct sk_buff *skb);

extern int xfrm4_extract_input(struct xfrm_state *x, 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,

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_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_register(struct xfrm_tunnel *handler);

extern int xfrm4_mode_tunnel_input_deregister(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_header(struct sk_buff *skb);

extern int xfrm6_extract_input(struct xfrm_state *x, 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);

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_output_finish(struct sk_buff *skb);

extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,

extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,

				 u8 **prevhdr);

				 u8 **prevhdr);

extern void xfrm6_local_error(struct sk_buff *skb, u32 mtu);





#ifdef CONFIG_XFRM

#ifdef CONFIG_XFRM

extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);

extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);

net/ipv4/xfrm4_output.c

+10 −2
Original line number Original line Diff line number Diff line
@@ -33,8 +33,7 @@ static int xfrm4_tunnel_check_size(struct sk_buff *skb) 
	mtu = dst_mtu(dst);

	mtu = dst_mtu(dst);

	if (skb->len > mtu) {

	if (skb->len > mtu) {

		if (skb->sk)

		if (skb->sk)

			ip_local_error(skb->sk, EMSGSIZE, ip_hdr(skb)->daddr,

			xfrm_local_error(skb, mtu);

				       inet_sk(skb->sk)->inet_dport, mtu);

		else

		else

			icmp_send(skb, ICMP_DEST_UNREACH,

			icmp_send(skb, ICMP_DEST_UNREACH,

				  ICMP_FRAG_NEEDED, htonl(mtu));

				  ICMP_FRAG_NEEDED, htonl(mtu));
@@ -99,3 +98,12 @@ int xfrm4_output(struct sk_buff *skb) 
			    x->outer_mode->afinfo->output_finish,

			    x->outer_mode->afinfo->output_finish,

			    !(IPCB(skb)->flags & IPSKB_REROUTED));

			    !(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);

}

net/ipv4/xfrm4_state.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -83,6 +83,7 @@ static struct xfrm_state_afinfo xfrm4_state_afinfo = { 
	.extract_input		= xfrm4_extract_input,

	.extract_input		= xfrm4_extract_input,

	.extract_output		= xfrm4_extract_output,

	.extract_output		= xfrm4_extract_output,

	.transport_finish	= xfrm4_transport_finish,

	.transport_finish	= xfrm4_transport_finish,

	.local_error		= xfrm4_local_error,

};

};





void __init xfrm4_state_init(void)

void __init xfrm4_state_init(void)

net/ipv6/xfrm6_output.c

+6 −4
Original line number Original line Diff line number Diff line
@@ -34,8 +34,10 @@ static int xfrm6_local_dontfrag(struct sk_buff *skb) 
	struct sock *sk = skb->sk;

	struct sock *sk = skb->sk;





	if (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)

		if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)

			return inet6_sk(sk)->dontfrag;

			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);

	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 flowi6 fl6;

	struct sock *sk = skb->sk;

	struct sock *sk = skb->sk;
@@ -80,7 +82,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb) 
		if (xfrm6_local_dontfrag(skb))

		if (xfrm6_local_dontfrag(skb))

			xfrm6_local_rxpmtu(skb, mtu);

			xfrm6_local_rxpmtu(skb, mtu);

		else if (skb->sk)

		else if (skb->sk)

			xfrm6_local_error(skb, mtu);

			xfrm_local_error(skb, mtu);

		else

		else

			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);

		ret = -EMSGSIZE;

		ret = -EMSGSIZE;
@@ -142,7 +144,7 @@ static int __xfrm6_output(struct sk_buff *skb) 
		xfrm6_local_rxpmtu(skb, mtu);

		xfrm6_local_rxpmtu(skb, mtu);

		return -EMSGSIZE;

		return -EMSGSIZE;

	} else if (!skb->local_df && skb->len > mtu && skb->sk) {

	} else if (!skb->local_df && skb->len > mtu && skb->sk) {

		xfrm6_local_error(skb, mtu);

		xfrm_local_error(skb, mtu);

		return -EMSGSIZE;

		return -EMSGSIZE;

	}

	}

net/ipv6/xfrm6_state.c

+1 −0
Original line number Original line Diff line number Diff line
@@ -183,6 +183,7 @@ static struct xfrm_state_afinfo xfrm6_state_afinfo = { 
	.extract_input		= xfrm6_extract_input,

	.extract_input		= xfrm6_extract_input,

	.extract_output		= xfrm6_extract_output,

	.extract_output		= xfrm6_extract_output,

	.transport_finish	= xfrm6_transport_finish,

	.transport_finish	= xfrm6_transport_finish,

	.local_error		= xfrm6_local_error,

};

};





int __init xfrm6_state_init(void)

int __init xfrm6_state_init(void)