From fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9 Mon Sep 17 00:00:00 2001 From: Dmitry Mishin Date: Thu, 31 Aug 2006 15:28:39 -0700 Subject: [NET]: Fix sk->sk_filter field access 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 Signed-off-by: Alexey Kuznetsov Signed-off-by: Kirill Korotaev --- include/net/sock.h | 34 +++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-) (limited to 'include/net/sock.h') diff --git a/include/net/sock.h b/include/net/sock.h index 337ebec84c70..edd4d73ce7f5 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -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) -- cgit v1.2.1