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authorDmitry Mishin <dim@openvz.org>2006-08-31 15:28:39 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2006-09-22 15:18:47 -0700
commitfda9ef5d679b07c9d9097aaf6ef7f069d794a8f9 (patch)
tree6a265dc2038bc5568c5a499e6c8d4733650ed3f7 /include
parentdc435e6dac1439340eaeceef84022c4e4749796d (diff)
[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.h13
-rw-r--r--include/net/sock.h34
2 files changed, 24 insertions, 23 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h
index c6cb8f09508..91b2e3b9251 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 337ebec84c7..edd4d73ce7f 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)