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| 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 /net/packet | |
| parent | dc435e6dac1439340eaeceef84022c4e4749796d (diff) | |
| download | linux-fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9.tar.gz linux-fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9.tar.bz2 linux-fda9ef5d679b07c9d9097aaf6ef7f069d794a8f9.zip | |
[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/packet')
| -rw-r--r-- | net/packet/af_packet.c | 43 |
1 files changed, 18 insertions, 25 deletions
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; |