diff options
| author | Dmitry Mishin <dim@openvz.org> | 2006-08-31 15:28:39 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2006-09-22 15:18:47 -0700 |
| commit | fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9 (patch) | |
| tree | 6a265dc2038bc5568c5a499e6c8d4733650ed3f7 /include | |
| parent | dc435e6dac1439340eaeceef84022c4e4749796d (diff) | |
| download | linux-fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9.tar.gz | |
[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 <dim@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/filter.h | 13 | ||||
| -rw-r--r-- | include/net/sock.h | 34 |
2 files changed, 24 insertions, 23 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index c6cb8f095088aa..91b2e3b9251eb6 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -25,10 +25,10 @@ struct sock_filter /* Filter block */ { - __u16 code; /* Actual filter code */ - __u8 jt; /* Jump true */ - __u8 jf; /* Jump false */ - __u32 k; /* Generic multiuse field */ + __u16 code; /* Actual filter code */ + __u8 jt; /* Jump true */ + __u8 jf; /* Jump false */ + __u32 k; /* Generic multiuse field */ }; struct sock_fprog /* Required for SO_ATTACH_FILTER. */ @@ -41,8 +41,9 @@ struct sock_fprog /* Required for SO_ATTACH_FILTER. */ struct sk_filter { atomic_t refcnt; - unsigned int len; /* Number of filter blocks */ - struct sock_filter insns[0]; + unsigned int len; /* Number of filter blocks */ + struct rcu_head rcu; + struct sock_filter insns[0]; }; static inline unsigned int sk_filter_len(struct sk_filter *fp) diff --git a/include/net/sock.h b/include/net/sock.h index 337ebec84c700e..edd4d73ce7f5cb 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) |