[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>
diff --git a/include/linux/filter.h b/include/linux/filter.h
index c6cb8f0..91b2e3b 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 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)