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Commit 628e341f319f1a64a4639088faba952e4ec8f0a8

Authored by Hannes Frederic Sowa
Committed by Steffen Klassert
1 parent d9bf5f1309
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

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>

Showing 7 changed files with 39 additions and 11 deletions Side-by-side Diff

... ... @@ -341,10 +341,13 @@
341 341 struct sk_buff *skb);
342 342 int (*transport_finish)(struct sk_buff *skb,
343 343 int async);
  344 + void (*local_error)(struct sk_buff *skb, u32 mtu);
344 345 };
345 346  
346 347 extern int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo);
347 348 extern int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo);
  349 +extern struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
  350 +extern void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);
348 351  
349 352 extern void xfrm_state_delete_tunnel(struct xfrm_state *x);
350 353  
... ... @@ -1477,6 +1480,7 @@
1477 1480 extern int xfrm_output_resume(struct sk_buff *skb, int err);
1478 1481 extern int xfrm_output(struct sk_buff *skb);
1479 1482 extern int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
  1483 +extern void xfrm_local_error(struct sk_buff *skb, int mtu);
1480 1484 extern int xfrm4_extract_header(struct sk_buff *skb);
1481 1485 extern int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb);
1482 1486 extern int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
... ... @@ -1497,6 +1501,7 @@
1497 1501 extern int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family);
1498 1502 extern int xfrm4_mode_tunnel_input_register(struct xfrm_tunnel *handler);
1499 1503 extern int xfrm4_mode_tunnel_input_deregister(struct xfrm_tunnel *handler);
  1504 +extern void xfrm4_local_error(struct sk_buff *skb, u32 mtu);
1500 1505 extern int xfrm6_extract_header(struct sk_buff *skb);
1501 1506 extern int xfrm6_extract_input(struct xfrm_state *x, struct sk_buff *skb);
1502 1507 extern int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi);
... ... @@ -1514,6 +1519,7 @@
1514 1519 extern int xfrm6_output_finish(struct sk_buff *skb);
1515 1520 extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
1516 1521 u8 **prevhdr);
  1522 +extern void xfrm6_local_error(struct sk_buff *skb, u32 mtu);
1517 1523  
1518 1524 #ifdef CONFIG_XFRM
1519 1525 extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
net/ipv4/xfrm4_output.c
Diff comments   View file @ 628e341
... ... @@ -33,8 +33,7 @@
33 33 mtu = dst_mtu(dst);
34 34 if (skb->len > mtu) {
35 35 if (skb->sk)
36   - ip_local_error(skb->sk, EMSGSIZE, ip_hdr(skb)->daddr,
37   - inet_sk(skb->sk)->inet_dport, mtu);
  36 + xfrm_local_error(skb, mtu);
38 37 else
39 38 icmp_send(skb, ICMP_DEST_UNREACH,
40 39 ICMP_FRAG_NEEDED, htonl(mtu));
... ... @@ -98,5 +97,14 @@
98 97 NULL, dst->dev,
99 98 x->outer_mode->afinfo->output_finish,
100 99 !(IPCB(skb)->flags & IPSKB_REROUTED));
  100 +}
  101 +
  102 +void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
  103 +{
  104 + struct iphdr *hdr;
  105 +
  106 + hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
  107 + ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
  108 + inet_sk(skb->sk)->inet_dport, mtu);
101 109 }
net/ipv4/xfrm4_state.c
Diff comments   View file @ 628e341
... ... @@ -83,6 +83,7 @@
83 83 .extract_input = xfrm4_extract_input,
84 84 .extract_output = xfrm4_extract_output,
85 85 .transport_finish = xfrm4_transport_finish,
  86 + .local_error = xfrm4_local_error,
86 87 };
87 88  
88 89 void __init xfrm4_state_init(void)
net/ipv6/xfrm6_output.c
Diff comments   View file @ 628e341
... ... @@ -34,8 +34,10 @@
34 34 struct sock *sk = skb->sk;
35 35  
36 36 if (sk) {
37   - proto = sk->sk_protocol;
  37 + if (sk->sk_family != AF_INET6)
  38 + return 0;
38 39  
  40 + proto = sk->sk_protocol;
39 41 if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
40 42 return inet6_sk(sk)->dontfrag;
41 43 }
... ... @@ -54,7 +56,7 @@
54 56 ipv6_local_rxpmtu(sk, &fl6, mtu);
55 57 }
56 58  
57   -static void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
  59 +void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
58 60 {
59 61 struct flowi6 fl6;
60 62 struct sock *sk = skb->sk;
... ... @@ -80,7 +82,7 @@
80 82 if (xfrm6_local_dontfrag(skb))
81 83 xfrm6_local_rxpmtu(skb, mtu);
82 84 else if (skb->sk)
83   - xfrm6_local_error(skb, mtu);
  85 + xfrm_local_error(skb, mtu);
84 86 else
85 87 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
86 88 ret = -EMSGSIZE;
... ... @@ -142,7 +144,7 @@
142 144 xfrm6_local_rxpmtu(skb, mtu);
143 145 return -EMSGSIZE;
144 146 } else if (!skb->local_df && skb->len > mtu && skb->sk) {
145   - xfrm6_local_error(skb, mtu);
  147 + xfrm_local_error(skb, mtu);
146 148 return -EMSGSIZE;
147 149 }
148 150  
net/ipv6/xfrm6_state.c
Diff comments   View file @ 628e341
... ... @@ -183,6 +183,7 @@
183 183 .extract_input = xfrm6_extract_input,
184 184 .extract_output = xfrm6_extract_output,
185 185 .transport_finish = xfrm6_transport_finish,
  186 + .local_error = xfrm6_local_error,
186 187 };
187 188  
188 189 int __init xfrm6_state_init(void)
net/xfrm/xfrm_output.c
Diff comments   View file @ 628e341
... ... @@ -214,6 +214,19 @@
214 214 return inner_mode->afinfo->extract_output(x, skb);
215 215 }
216 216  
  217 +void xfrm_local_error(struct sk_buff *skb, int mtu)
  218 +{
  219 + struct xfrm_state_afinfo *afinfo;
  220 +
  221 + afinfo = xfrm_state_get_afinfo(skb->sk->sk_family);
  222 + if (!afinfo)
  223 + return;
  224 +
  225 + afinfo->local_error(skb, mtu);
  226 + xfrm_state_put_afinfo(afinfo);
  227 +}
  228 +
217 229 EXPORT_SYMBOL_GPL(xfrm_output);
218 230 EXPORT_SYMBOL_GPL(xfrm_inner_extract_output);
  231 +EXPORT_SYMBOL_GPL(xfrm_local_error);
net/xfrm/xfrm_state.c
Diff comments   View file @ 628e341
... ... @@ -39,9 +39,6 @@
39 39  
40 40 static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024;
41 41  
42   -static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
43   -static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);
44   -
45 42 static inline unsigned int xfrm_dst_hash(struct net *net,
46 43 const xfrm_address_t *daddr,
47 44 const xfrm_address_t *saddr,
... ... @@ -1860,7 +1857,7 @@
1860 1857 }
1861 1858 EXPORT_SYMBOL(xfrm_state_unregister_afinfo);
1862 1859  
1863   -static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
  1860 +struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
1864 1861 {
1865 1862 struct xfrm_state_afinfo *afinfo;
1866 1863 if (unlikely(family >= NPROTO))
... ... @@ -1872,7 +1869,7 @@
1872 1869 return afinfo;
1873 1870 }
1874 1871  
1875   -static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
  1872 +void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
1876 1873 {
1877 1874 rcu_read_unlock();
1878 1875 }