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net: fix nulls list corruptions in sk_prot_alloc

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Special care is taken inside sk_port_alloc to avoid overwriting
skc_node/skc_nulls_node. We should also avoid overwriting
skc_bind_node/skc_portaddr_node.

The patch fixes the following crash:

 BUG: unable to handle kernel paging request at fffffffffffffff0
 IP: [<ffffffff812ec6dd>] udp4_lib_lookup2+0xad/0x370
 [<ffffffff812ecc22>] __udp4_lib_lookup+0x282/0x360
 [<ffffffff812ed63e>] __udp4_lib_rcv+0x31e/0x700
 [<ffffffff812bba45>] ? ip_local_deliver_finish+0x65/0x190
 [<ffffffff812bbbf8>] ? ip_local_deliver+0x88/0xa0
 [<ffffffff812eda35>] udp_rcv+0x15/0x20
 [<ffffffff812bba45>] ip_local_deliver_finish+0x65/0x190
 [<ffffffff812bbbf8>] ip_local_deliver+0x88/0xa0
 [<ffffffff812bb2cd>] ip_rcv_finish+0x32d/0x6f0
 [<ffffffff8128c14c>] ? netif_receive_skb+0x99c/0x11c0
 [<ffffffff812bb94b>] ip_rcv+0x2bb/0x350
 [<ffffffff8128c14c>] netif_receive_skb+0x99c/0x11c0

Signed-off-by: Leonard Crestez <lcrestez@ixiacom.com>
Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Octavian Purdila 2010-12-16 14:26:56 -08:00 committed by David S. Miller
parent 2984961c38
commit fcbdf09d96
6 changed files with 42 additions and 12 deletions
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3
include/net/sock.h
View File

@ -754,6 +754,7 @@ struct proto {
void (*unhash)(struct sock *sk);
void (*rehash)(struct sock *sk);
int (*get_port)(struct sock *sk, unsigned short snum);
void (*clear_sk)(struct sock *sk, int size);
/* Keeping track of sockets in use */
#ifdef CONFIG_PROC_FS
@ -852,6 +853,8 @@ static inline void __sk_prot_rehash(struct sock *sk)
sk->sk_prot->hash(sk);
}
void sk_prot_clear_portaddr_nulls(struct sock *sk, int size);
/* About 10 seconds */
#define SOCK_DESTROY_TIME (10*HZ)

47
net/core/sock.c
View File

@ -1009,6 +1009,36 @@ static void sock_copy(struct sock *nsk, const struct sock *osk)
#endif
}
/*
* caches using SLAB_DESTROY_BY_RCU should let .next pointer from nulls nodes
* un-modified. Special care is taken when initializing object to zero.
*/
static inline void sk_prot_clear_nulls(struct sock *sk, int size)
{
if (offsetof(struct sock, sk_node.next) != 0)
memset(sk, 0, offsetof(struct sock, sk_node.next));
memset(&sk->sk_node.pprev, 0,
size - offsetof(struct sock, sk_node.pprev));
}
void sk_prot_clear_portaddr_nulls(struct sock *sk, int size)
{
unsigned long nulls1, nulls2;
nulls1 = offsetof(struct sock, __sk_common.skc_node.next);
nulls2 = offsetof(struct sock, __sk_common.skc_portaddr_node.next);
if (nulls1 > nulls2)
swap(nulls1, nulls2);
if (nulls1 != 0)
memset((char *)sk, 0, nulls1);
memset((char *)sk + nulls1 + sizeof(void *), 0,
nulls2 - nulls1 - sizeof(void *));
memset((char *)sk + nulls2 + sizeof(void *), 0,
size - nulls2 - sizeof(void *));
}
EXPORT_SYMBOL(sk_prot_clear_portaddr_nulls);
static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
int family)
{
@ -1021,19 +1051,12 @@ static struct sock *sk_prot_alloc(struct proto *prot, gfp_t priority,
if (!sk)
return sk;
if (priority & __GFP_ZERO) {
/*
* caches using SLAB_DESTROY_BY_RCU should let
* sk_node.next un-modified. Special care is taken
* when initializing object to zero.
*/
if (offsetof(struct sock, sk_node.next) != 0)
memset(sk, 0, offsetof(struct sock, sk_node.next));
memset(&sk->sk_node.pprev, 0,
prot->obj_size - offsetof(struct sock,
sk_node.pprev));
}
}
if (prot->clear_sk)
prot->clear_sk(sk, prot->obj_size);
else
sk_prot_clear_nulls(sk, prot->obj_size);
}
} else
sk = kmalloc(prot->obj_size, priority);
if (sk != NULL) {

1
net/ipv4/udp.c
View File

@ -1899,6 +1899,7 @@ struct proto udp_prot = {
.compat_setsockopt = compat_udp_setsockopt,
.compat_getsockopt = compat_udp_getsockopt,
#endif
.clear_sk = sk_prot_clear_portaddr_nulls,
};
EXPORT_SYMBOL(udp_prot);

1
net/ipv4/udplite.c
View File

@ -57,6 +57,7 @@ struct proto udplite_prot = {
.compat_setsockopt = compat_udp_setsockopt,
.compat_getsockopt = compat_udp_getsockopt,
#endif
.clear_sk = sk_prot_clear_portaddr_nulls,
};
EXPORT_SYMBOL(udplite_prot);

1
net/ipv6/udp.c
View File

@ -1477,6 +1477,7 @@ struct proto udpv6_prot = {
.compat_setsockopt = compat_udpv6_setsockopt,
.compat_getsockopt = compat_udpv6_getsockopt,
#endif
.clear_sk = sk_prot_clear_portaddr_nulls,
};
static struct inet_protosw udpv6_protosw = {

1
net/ipv6/udplite.c
View File

@ -55,6 +55,7 @@ struct proto udplitev6_prot = {
.compat_setsockopt = compat_udpv6_setsockopt,
.compat_getsockopt = compat_udpv6_getsockopt,
#endif
.clear_sk = sk_prot_clear_portaddr_nulls,
};
static struct inet_protosw udplite6_protosw = {