net: convert sock.sk_wmem_alloc from atomic_t to refcount_t

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 14 insertions, 14 deletions

diff --git a/net/atm/br2684.c b/net/atm/br2684.c
index fca84e111c89..4e111196f902 100644
--- a/net/atm/br2684.c
+++ b/net/atm/br2684.c
@@ -252,7 +252,7 @@ static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev,
 
 	ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
-	atomic_add(skb->truesize, &sk_atm(atmvcc)->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk_atm(atmvcc)->sk_wmem_alloc);
 	ATM_SKB(skb)->atm_options = atmvcc->atm_options;
 	dev->stats.tx_packets++;
 	dev->stats.tx_bytes += skb->len;
diff --git a/net/atm/clip.c b/net/atm/clip.c
index 47c36f449df0..f271a7bcf5b2 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -381,7 +381,7 @@ static netdev_tx_t clip_start_xmit(struct sk_buff *skb,
 		memcpy(here, llc_oui, sizeof(llc_oui));
 		((__be16 *) here)[3] = skb->protocol;
 	}
-	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
 	ATM_SKB(skb)->atm_options = vcc->atm_options;
 	entry->vccs->last_use = jiffies;
 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, vcc, vcc->dev);
diff --git a/net/atm/common.c b/net/atm/common.c
index f06422f4108d..8a4f99114cd2 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -80,9 +80,9 @@ static void vcc_sock_destruct(struct sock *sk)
 		printk(KERN_DEBUG "%s: rmem leakage (%d bytes) detected.\n",
 		       __func__, atomic_read(&sk->sk_rmem_alloc));
 
-	if (atomic_read(&sk->sk_wmem_alloc))
+	if (refcount_read(&sk->sk_wmem_alloc))
 		printk(KERN_DEBUG "%s: wmem leakage (%d bytes) detected.\n",
-		       __func__, atomic_read(&sk->sk_wmem_alloc));
+		       __func__, refcount_read(&sk->sk_wmem_alloc));
 }
 
 static void vcc_def_wakeup(struct sock *sk)
@@ -101,7 +101,7 @@ static inline int vcc_writable(struct sock *sk)
 	struct atm_vcc *vcc = atm_sk(sk);
 
 	return (vcc->qos.txtp.max_sdu +
-		atomic_read(&sk->sk_wmem_alloc)) <= sk->sk_sndbuf;
+		refcount_read(&sk->sk_wmem_alloc)) <= sk->sk_sndbuf;
 }
 
 static void vcc_write_space(struct sock *sk)
@@ -156,7 +156,7 @@ int vcc_create(struct net *net, struct socket *sock, int protocol, int family, i
 	memset(&vcc->local, 0, sizeof(struct sockaddr_atmsvc));
 	memset(&vcc->remote, 0, sizeof(struct sockaddr_atmsvc));
 	vcc->qos.txtp.max_sdu = 1 << 16; /* for meta VCs */
-	atomic_set(&sk->sk_wmem_alloc, 1);
+	refcount_set(&sk->sk_wmem_alloc, 1);
 	atomic_set(&sk->sk_rmem_alloc, 0);
 	vcc->push = NULL;
 	vcc->pop = NULL;
@@ -630,7 +630,7 @@ int vcc_sendmsg(struct socket *sock, struct msghdr *m, size_t size)
 		goto out;
 	}
 	pr_debug("%d += %d\n", sk_wmem_alloc_get(sk), skb->truesize);
-	atomic_add(skb->truesize, &sk->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk->sk_wmem_alloc);
 
 	skb->dev = NULL; /* for paths shared with net_device interfaces */
 	ATM_SKB(skb)->atm_options = vcc->atm_options;
diff --git a/net/atm/lec.c b/net/atm/lec.c
index 09cfe87f0a44..75545717fa46 100644
--- a/net/atm/lec.c
+++ b/net/atm/lec.c
@@ -181,7 +181,7 @@ lec_send(struct atm_vcc *vcc, struct sk_buff *skb)
 	ATM_SKB(skb)->vcc = vcc;
 	ATM_SKB(skb)->atm_options = vcc->atm_options;
 
-	atomic_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
 	if (vcc->send(vcc, skb) < 0) {
 		dev->stats.tx_dropped++;
 		return;
@@ -345,7 +345,7 @@ static int lec_atm_send(struct atm_vcc *vcc, struct sk_buff *skb)
 	int i;
 	char *tmp;		/* FIXME */
 
-	atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+	WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
 	mesg = (struct atmlec_msg *)skb->data;
 	tmp = skb->data;
 	tmp += sizeof(struct atmlec_msg);
diff --git a/net/atm/mpc.c b/net/atm/mpc.c
index a190800572bd..680a4b9095a1 100644
--- a/net/atm/mpc.c
+++ b/net/atm/mpc.c
@@ -555,7 +555,7 @@ static int send_via_shortcut(struct sk_buff *skb, struct mpoa_client *mpc)
 					sizeof(struct llc_snap_hdr));
 	}
 
-	atomic_add(skb->truesize, &sk_atm(entry->shortcut)->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk_atm(entry->shortcut)->sk_wmem_alloc);
 	ATM_SKB(skb)->atm_options = entry->shortcut->atm_options;
 	entry->shortcut->send(entry->shortcut, skb);
 	entry->packets_fwded++;
@@ -911,7 +911,7 @@ static int msg_from_mpoad(struct atm_vcc *vcc, struct sk_buff *skb)
 
 	struct mpoa_client *mpc = find_mpc_by_vcc(vcc);
 	struct k_message *mesg = (struct k_message *)skb->data;
-	atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+	WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
 
 	if (mpc == NULL) {
 		pr_info("no mpc found\n");
diff --git a/net/atm/pppoatm.c b/net/atm/pppoatm.c
index c4e09846d1de..21d9d341a619 100644
--- a/net/atm/pppoatm.c
+++ b/net/atm/pppoatm.c
@@ -350,7 +350,7 @@ static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
 		return 1;
 	}
 
-	atomic_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc);
+	refcount_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc);
 	ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n",
 		 skb, ATM_SKB(skb)->vcc, ATM_SKB(skb)->vcc->dev);
diff --git a/net/atm/raw.c b/net/atm/raw.c
index 2e17e97a7a8b..821c0797553d 100644
--- a/net/atm/raw.c
+++ b/net/atm/raw.c
@@ -35,7 +35,7 @@ static void atm_pop_raw(struct atm_vcc *vcc, struct sk_buff *skb)
 
 	pr_debug("(%d) %d -= %d\n",
 		 vcc->vci, sk_wmem_alloc_get(sk), skb->truesize);
-	atomic_sub(skb->truesize, &sk->sk_wmem_alloc);
+	WARN_ON(refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc));
 	dev_kfree_skb_any(skb);
 	sk->sk_write_space(sk);
 }
diff --git a/net/atm/signaling.c b/net/atm/signaling.c
index f640a99e14b8..983c3a21a133 100644
--- a/net/atm/signaling.c
+++ b/net/atm/signaling.c
@@ -67,7 +67,7 @@ static int sigd_send(struct atm_vcc *vcc, struct sk_buff *skb)
 	struct sock *sk;
 
 	msg = (struct atmsvc_msg *) skb->data;
-	atomic_sub(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc);
+	WARN_ON(refcount_sub_and_test(skb->truesize, &sk_atm(vcc)->sk_wmem_alloc));
 	vcc = *(struct atm_vcc **) &msg->vcc;
 	pr_debug("%d (0x%lx)\n", (int)msg->type, (unsigned long)vcc);
 	sk = sk_atm(vcc);