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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 /net
parentdc435e6dac1439340eaeceef84022c4e4749796d (diff)
downloadlinux-fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9.tar.bz2
[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 'net')
-rw-r--r--net/core/filter.c8
-rw-r--r--net/core/sock.c22
-rw-r--r--net/dccp/ipv6.c2
-rw-r--r--net/decnet/dn_nsp_in.c2
-rw-r--r--net/ipv4/tcp_ipv4.c2
-rw-r--r--net/ipv6/tcp_ipv6.c4
-rw-r--r--net/packet/af_packet.c43
-rw-r--r--net/sctp/input.c2
8 files changed, 37 insertions, 48 deletions
diff --git a/net/core/filter.c b/net/core/filter.c
index 5b4486a60cf6..6732782a5a40 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -422,10 +422,10 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
if (!err) {
struct sk_filter *old_fp;
- spin_lock_bh(&sk->sk_lock.slock);
- old_fp = sk->sk_filter;
- sk->sk_filter = fp;
- spin_unlock_bh(&sk->sk_lock.slock);
+ rcu_read_lock_bh();
+ old_fp = rcu_dereference(sk->sk_filter);
+ rcu_assign_pointer(sk->sk_filter, fp);
+ rcu_read_unlock_bh();
fp = old_fp;
}
diff --git a/net/core/sock.c b/net/core/sock.c
index cfaf09039b02..b77e155cbe6c 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -247,11 +247,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
goto out;
}
- /* It would be deadlock, if sock_queue_rcv_skb is used
- with socket lock! We assume that users of this
- function are lock free.
- */
- err = sk_filter(sk, skb, 1);
+ err = sk_filter(sk, skb);
if (err)
goto out;
@@ -278,7 +274,7 @@ int sk_receive_skb(struct sock *sk, struct sk_buff *skb)
{
int rc = NET_RX_SUCCESS;
- if (sk_filter(sk, skb, 0))
+ if (sk_filter(sk, skb))
goto discard_and_relse;
skb->dev = NULL;
@@ -606,15 +602,15 @@ set_rcvbuf:
break;
case SO_DETACH_FILTER:
- spin_lock_bh(&sk->sk_lock.slock);
- filter = sk->sk_filter;
+ rcu_read_lock_bh();
+ filter = rcu_dereference(sk->sk_filter);
if (filter) {
- sk->sk_filter = NULL;
- spin_unlock_bh(&sk->sk_lock.slock);
+ rcu_assign_pointer(sk->sk_filter, NULL);
sk_filter_release(sk, filter);
+ rcu_read_unlock_bh();
break;
}
- spin_unlock_bh(&sk->sk_lock.slock);
+ rcu_read_unlock_bh();
ret = -ENONET;
break;
@@ -884,10 +880,10 @@ void sk_free(struct sock *sk)
if (sk->sk_destruct)
sk->sk_destruct(sk);
- filter = sk->sk_filter;
+ filter = rcu_dereference(sk->sk_filter);
if (filter) {
sk_filter_release(sk, filter);
- sk->sk_filter = NULL;
+ rcu_assign_pointer(sk->sk_filter, NULL);
}
sock_disable_timestamp(sk);
diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index f9c5e12d7038..7a47399cf31f 100644
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -970,7 +970,7 @@ static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
if (skb->protocol == htons(ETH_P_IP))
return dccp_v4_do_rcv(sk, skb);
- if (sk_filter(sk, skb, 0))
+ if (sk_filter(sk, skb))
goto discard;
/*
diff --git a/net/decnet/dn_nsp_in.c b/net/decnet/dn_nsp_in.c
index 86f7f3b28e70..72ecc6e62ec4 100644
--- a/net/decnet/dn_nsp_in.c
+++ b/net/decnet/dn_nsp_in.c
@@ -586,7 +586,7 @@ static __inline__ int dn_queue_skb(struct sock *sk, struct sk_buff *skb, int sig
goto out;
}
- err = sk_filter(sk, skb, 0);
+ err = sk_filter(sk, skb);
if (err)
goto out;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 23b46e36b147..39b179856082 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1104,7 +1104,7 @@ process:
goto discard_and_relse;
nf_reset(skb);
- if (sk_filter(sk, skb, 0))
+ if (sk_filter(sk, skb))
goto discard_and_relse;
skb->dev = NULL;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2b18918f3011..2546fc9f0a78 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1075,7 +1075,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
if (skb->protocol == htons(ETH_P_IP))
return tcp_v4_do_rcv(sk, skb);
- if (sk_filter(sk, skb, 0))
+ if (sk_filter(sk, skb))
goto discard;
/*
@@ -1232,7 +1232,7 @@ process:
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
- if (sk_filter(sk, skb, 0))
+ if (sk_filter(sk, skb))
goto discard_and_relse;
skb->dev = NULL;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 300215bdbf46..f4ccb90e6739 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -427,21 +427,24 @@ out_unlock:
}
#endif
-static inline unsigned run_filter(struct sk_buff *skb, struct sock *sk, unsigned res)
+static inline int run_filter(struct sk_buff *skb, struct sock *sk,
+ unsigned *snaplen)
{
struct sk_filter *filter;
+ int err = 0;
- bh_lock_sock(sk);
- filter = sk->sk_filter;
- /*
- * Our caller already checked that filter != NULL but we need to
- * verify that under bh_lock_sock() to be safe
- */
- if (likely(filter != NULL))
- res = sk_run_filter(skb, filter->insns, filter->len);
- bh_unlock_sock(sk);
+ rcu_read_lock_bh();
+ filter = rcu_dereference(sk->sk_filter);
+ if (filter != NULL) {
+ err = sk_run_filter(skb, filter->insns, filter->len);
+ if (!err)
+ err = -EPERM;
+ else if (*snaplen > err)
+ *snaplen = err;
+ }
+ rcu_read_unlock_bh();
- return res;
+ return err;
}
/*
@@ -491,13 +494,8 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, struct packet
snaplen = skb->len;
- if (sk->sk_filter) {
- unsigned res = run_filter(skb, sk, snaplen);
- if (res == 0)
- goto drop_n_restore;
- if (snaplen > res)
- snaplen = res;
- }
+ if (run_filter(skb, sk, &snaplen) < 0)
+ goto drop_n_restore;
if (atomic_read(&sk->sk_rmem_alloc) + skb->truesize >=
(unsigned)sk->sk_rcvbuf)
@@ -593,13 +591,8 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct packe
snaplen = skb->len;
- if (sk->sk_filter) {
- unsigned res = run_filter(skb, sk, snaplen);
- if (res == 0)
- goto drop_n_restore;
- if (snaplen > res)
- snaplen = res;
- }
+ if (run_filter(skb, sk, &snaplen) < 0)
+ goto drop_n_restore;
if (sk->sk_type == SOCK_DGRAM) {
macoff = netoff = TPACKET_ALIGN(TPACKET_HDRLEN) + 16;
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 8a34d95602ce..03f65de75d88 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -228,7 +228,7 @@ int sctp_rcv(struct sk_buff *skb)
goto discard_release;
nf_reset(skb);
- if (sk_filter(sk, skb, 1))
+ if (sk_filter(sk, skb))
goto discard_release;
/* Create an SCTP packet structure. */