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[NET]: Fix sk->sk_filter field access

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Function sk_filter() is called from tcp_v{4,6}_rcv() functions with arg
needlock = 0, while socket is not locked at that moment. In order to avoid
this and similar issues in the future, use rcu for sk->sk_filter field read
protection.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
This commit is contained in:
Dmitry Mishin 2006-08-31 15:28:39 -07:00 • committed by David S. Miller
parent dc435e6dac
commit fda9ef5d67
10 changed files with 61 additions and 71 deletions
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34
include/net/sock.h
View file

@ -862,30 +862,24 @@ extern void sock_init_data(struct socket *sock, struct sock *sk);
*
*/
static inline int sk_filter(struct sock *sk, struct sk_buff *skb, int needlock)
static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
{
int err;
struct sk_filter *filter;
err = security_sock_rcv_skb(sk, skb);
if (err)
return err;
if (sk->sk_filter) {
struct sk_filter *filter;
if (needlock)
bh_lock_sock(sk);
filter = sk->sk_filter;
if (filter) {
unsigned int pkt_len = sk_run_filter(skb, filter->insns,
filter->len);
err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
}
if (needlock)
bh_unlock_sock(sk);
rcu_read_lock_bh();
filter = sk->sk_filter;
if (filter) {
unsigned int pkt_len = sk_run_filter(skb, filter->insns,
filter->len);
err = pkt_len ? pskb_trim(skb, pkt_len) : -EPERM;
}
rcu_read_unlock_bh();
return err;
}
@ -897,6 +891,12 @@ static inline int sk_filter(struct sock *sk, struct sk_buff *skb, int needlock)
* Remove a filter from a socket and release its resources.
*/
static inline void sk_filter_rcu_free(struct rcu_head *rcu)
{
struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu);
kfree(fp);
}
static inline void sk_filter_release(struct sock *sk, struct sk_filter *fp)
{
unsigned int size = sk_filter_len(fp);
@ -904,7 +904,7 @@ static inline void sk_filter_release(struct sock *sk, struct sk_filter *fp)
atomic_sub(size, &sk->sk_omem_alloc);
if (atomic_dec_and_test(&fp->refcnt))
kfree(fp);
call_rcu_bh(&fp->rcu, sk_filter_rcu_free);
}
static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)