packet: fix races in fanout_add()

[pandora-kernel.git] / net / packet / af_packet.c

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index ca39a0c..146b2d7 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1170,16 +1170,6 @@ static void packet_sock_destruct(struct sock *sk)
        sk_refcnt_debug_dec(sk);
 }
 
-static int fanout_rr_next(struct packet_fanout *f, unsigned int num)
-{
-       int x = atomic_read(&f->rr_cur) + 1;
-
-       if (x >= num)
-               x = 0;
-
-       return x;
-}
-
 static struct sock *fanout_demux_hash(struct packet_fanout *f, struct sk_buff *skb, unsigned int num)
 {
        u32 idx, hash = skb->rxhash;
@@ -1191,13 +1181,9 @@ static struct sock *fanout_demux_hash(struct packet_fanout *f, struct sk_buff *s
 
 static struct sock *fanout_demux_lb(struct packet_fanout *f, struct sk_buff *skb, unsigned int num)
 {
-       int cur, old;
+       unsigned int val = atomic_inc_return(&f->rr_cur);
 
-       cur = atomic_read(&f->rr_cur);
-       while ((old = atomic_cmpxchg(&f->rr_cur, cur,
-                                    fanout_rr_next(f, num))) != cur)
-               cur = old;
-       return f->arr[cur];
+       return f->arr[val % num];
 }
 
 static struct sock *fanout_demux_cpu(struct packet_fanout *f, struct sk_buff *skb, unsigned int num)
@@ -1277,10 +1263,10 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
 
 bool match_fanout_group(struct packet_type *ptype, struct sock * sk)
 {
-       if (ptype->af_packet_priv == (void*)((struct packet_sock *)sk)->fanout)
-               return true;
+       if (sk->sk_family != PF_PACKET)
+               return false;
 
-       return false;
+       return ptype->af_packet_priv == pkt_sk(sk)->fanout;
 }
 
 static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
@@ -1300,13 +1286,16 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
                return -EINVAL;
        }
 
+       mutex_lock(&fanout_mutex);
+
+       err = -EINVAL;
        if (!po->running)
-               return -EINVAL;
+               goto out;
 
+       err = -EALREADY;
        if (po->fanout)
-               return -EALREADY;
+               goto out;
 
-       mutex_lock(&fanout_mutex);
        match = NULL;
        list_for_each_entry(f, &fanout_list, list) {
                if (f->id == id &&
@@ -1362,17 +1351,16 @@ static void fanout_release(struct sock *sk)
        struct packet_sock *po = pkt_sk(sk);
        struct packet_fanout *f;
 
+       mutex_lock(&fanout_mutex);
        f = po->fanout;
-       if (!f)
-               return;
-
-       po->fanout = NULL;
+       if (f) {
+               po->fanout = NULL;
 
-       mutex_lock(&fanout_mutex);
-       if (atomic_dec_and_test(&f->sk_ref)) {
-               list_del(&f->list);
-               dev_remove_pack(&f->prot_hook);
-               kfree(f);
+               if (atomic_dec_and_test(&f->sk_ref)) {
+                       list_del(&f->list);
+                       dev_remove_pack(&f->prot_hook);
+                       kfree(f);
+               }
        }
        mutex_unlock(&fanout_mutex);
 }
@@ -3091,19 +3079,25 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv
 
                if (optlen != sizeof(val))
                        return -EINVAL;
-               if (po->rx_ring.pg_vec || po->tx_ring.pg_vec)
-                       return -EBUSY;
                if (copy_from_user(&val, optval, sizeof(val)))
                        return -EFAULT;
                switch (val) {
                case TPACKET_V1:
                case TPACKET_V2:
                case TPACKET_V3:
-                       po->tp_version = val;
-                       return 0;
+                       break;
                default:
                        return -EINVAL;
                }
+               lock_sock(sk);
+               if (po->rx_ring.pg_vec || po->tx_ring.pg_vec) {
+                       ret = -EBUSY;
+               } else {
+                       po->tp_version = val;
+                       ret = 0;
+               }
+               release_sock(sk);
+               return ret;
        }
        case PACKET_RESERVE:
        {
@@ -3574,6 +3568,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
        /* Added to avoid minimal code churn */
        struct tpacket_req *req = &req_u->req;
 
+       lock_sock(sk);
        /* Opening a Tx-ring is NOT supported in TPACKET_V3 */
        if (!closing && tx_ring && (po->tp_version > TPACKET_V2)) {
                WARN(1, "Tx-ring is not supported.\n");
@@ -3651,7 +3646,6 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
                        goto out;
        }
 
-       lock_sock(sk);
 
        /* Detach socket from network */
        spin_lock(&po->bind_lock);
@@ -3700,11 +3694,11 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
                if (!tx_ring)
                        prb_shutdown_retire_blk_timer(po, tx_ring, rb_queue);
        }
-       release_sock(sk);
 
        if (pg_vec)
                free_pg_vec(pg_vec, order, req->tp_block_nr);
 out:
+       release_sock(sk);
        return err;
 }