net: convert sock.sk_refcnt 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.

This patch uses refcount_inc_not_zero() instead of
atomic_inc_not_zero_hint() due to absense of a _hint()
version of refcount API. If the hint() version must
be used, we might need to revisit API.

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>

10 files changed, 19 insertions, 19 deletions

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index a3fa1a5b6d98..4089c013cb03 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -756,7 +756,7 @@ static void reqsk_queue_hash_req(struct request_sock *req,
 	 * are committed to memory and refcnt initialized.
 	 */
 	smp_wmb();
-	atomic_set(&req->rsk_refcnt, 2 + 1);
+	refcount_set(&req->rsk_refcnt, 2 + 1);
 }
 
 void inet_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index e9a59d2d91d4..a4be2c1cb688 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -246,7 +246,7 @@ EXPORT_SYMBOL_GPL(__inet_lookup_listener);
 /* All sockets share common refcount, but have different destructors */
 void sock_gen_put(struct sock *sk)
 {
-	if (!atomic_dec_and_test(&sk->sk_refcnt))
+	if (!refcount_dec_and_test(&sk->sk_refcnt))
 		return;
 
 	if (sk->sk_state == TCP_TIME_WAIT)
@@ -287,7 +287,7 @@ begin:
 			continue;
 		if (likely(INET_MATCH(sk, net, acookie,
 				      saddr, daddr, ports, dif))) {
-			if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
+			if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 				goto out;
 			if (unlikely(!INET_MATCH(sk, net, acookie,
 						 saddr, daddr, ports, dif))) {
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index f8aff2c71cde..5b039159e67a 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -76,7 +76,7 @@ void inet_twsk_free(struct inet_timewait_sock *tw)
 
 void inet_twsk_put(struct inet_timewait_sock *tw)
 {
-	if (atomic_dec_and_test(&tw->tw_refcnt))
+	if (refcount_dec_and_test(&tw->tw_refcnt))
 		inet_twsk_free(tw);
 }
 EXPORT_SYMBOL_GPL(inet_twsk_put);
@@ -131,7 +131,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 	 * We can use atomic_set() because prior spin_lock()/spin_unlock()
 	 * committed into memory all tw fields.
 	 */
-	atomic_set(&tw->tw_refcnt, 4);
+	refcount_set(&tw->tw_refcnt, 4);
 	inet_twsk_add_node_rcu(tw, &ehead->chain);
 
 	/* Step 3: Remove SK from hash chain */
@@ -195,7 +195,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 		 * to a non null value before everything is setup for this
 		 * timewait socket.
 		 */
-		atomic_set(&tw->tw_refcnt, 0);
+		refcount_set(&tw->tw_refcnt, 0);
 
 		__module_get(tw->tw_prot->owner);
 	}
@@ -278,7 +278,7 @@ restart:
 				atomic_read(&twsk_net(tw)->count))
 				continue;
 
-			if (unlikely(!atomic_inc_not_zero(&tw->tw_refcnt)))
+			if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
 				continue;
 
 			if (unlikely((tw->tw_family != family) ||
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index ccfbce13a633..b8f0db54b197 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -290,7 +290,7 @@ void ping_close(struct sock *sk, long timeout)
 {
 	pr_debug("ping_close(sk=%p,sk->num=%u)\n",
 		 inet_sk(sk), inet_sk(sk)->inet_num);
-	pr_debug("isk->refcnt = %d\n", sk->sk_refcnt.counter);
+	pr_debug("isk->refcnt = %d\n", refcount_read(&sk->sk_refcnt));
 
 	sk_common_release(sk);
 }
@@ -1127,7 +1127,7 @@ static void ping_v4_format_sock(struct sock *sp, struct seq_file *f,
 		0, 0L, 0,
 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
 		0, sock_i_ino(sp),
-		atomic_read(&sp->sk_refcnt), sp,
+		refcount_read(&sp->sk_refcnt), sp,
 		atomic_read(&sp->sk_drops));
 }
 
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index bdffad875691..b0bb5d0a30bd 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -1063,7 +1063,7 @@ static void raw_sock_seq_show(struct seq_file *seq, struct sock *sp, int i)
 		0, 0L, 0,
 		from_kuid_munged(seq_user_ns(seq), sock_i_uid(sp)),
 		0, sock_i_ino(sp),
-		atomic_read(&sp->sk_refcnt), sp, atomic_read(&sp->sk_drops));
+		refcount_read(&sp->sk_refcnt), sp, atomic_read(&sp->sk_drops));
 }
 
 static int raw_seq_show(struct seq_file *seq, void *v)
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 7835bb4a1fab..0905cf04c2a4 100644
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -213,7 +213,7 @@ struct sock *tcp_get_cookie_sock(struct sock *sk, struct sk_buff *skb,
 	child = icsk->icsk_af_ops->syn_recv_sock(sk, skb, req, dst,
 						 NULL, &own_req);
 	if (child) {
-		atomic_set(&req->rsk_refcnt, 1);
+		refcount_set(&req->rsk_refcnt, 1);
 		tcp_sk(child)->tsoffset = tsoff;
 		sock_rps_save_rxhash(child, skb);
 		inet_csk_reqsk_queue_add(sk, req, child);
diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 4af82b914dd4..8b1539efaf38 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -214,7 +214,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk,
 	inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS,
 				  TCP_TIMEOUT_INIT, TCP_RTO_MAX);
 
-	atomic_set(&req->rsk_refcnt, 2);
+	refcount_set(&req->rsk_refcnt, 2);
 
 	/* Now finish processing the fastopen child socket. */
 	inet_csk(child)->icsk_af_ops->rebuild_header(child);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index d774bcd9a54b..6ec6900eb300 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2323,7 +2323,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
 		icsk->icsk_probes_out,
 		sock_i_ino(sk),
-		atomic_read(&sk->sk_refcnt), sk,
+		refcount_read(&sk->sk_refcnt), sk,
 		jiffies_to_clock_t(icsk->icsk_rto),
 		jiffies_to_clock_t(icsk->icsk_ack.ato),
 		(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
@@ -2349,7 +2349,7 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw,
 		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK",
 		i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
 		3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
-		atomic_read(&tw->tw_refcnt), tw);
+		refcount_read(&tw->tw_refcnt), tw);
 }
 
 #define TMPSZ 150
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 86fad2a14ac4..25294d43e147 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -577,7 +577,7 @@ struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 
 	sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
 			       dif, &udp_table, NULL);
-	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
 		sk = NULL;
 	return sk;
 }
@@ -2242,7 +2242,7 @@ void udp_v4_early_demux(struct sk_buff *skb)
 					     uh->source, iph->saddr, dif);
 	}
 
-	if (!sk || !atomic_inc_not_zero_hint(&sk->sk_refcnt, 2))
+	if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
 		return;
 
 	skb->sk = sk;
@@ -2691,7 +2691,7 @@ static void udp4_format_sock(struct sock *sp, struct seq_file *f,
 		0, 0L, 0,
 		from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
 		0, sock_i_ino(sp),
-		atomic_read(&sp->sk_refcnt), sp,
+		refcount_read(&sp->sk_refcnt), sp,
 		atomic_read(&sp->sk_drops));
 }
 
diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
index 9a89c10a55f0..4515836d2a3a 100644
--- a/net/ipv4/udp_diag.c
+++ b/net/ipv4/udp_diag.c
@@ -55,7 +55,7 @@ static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,
 				req->id.idiag_dport,
 				req->id.idiag_if, tbl, NULL);
 #endif
-	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
 		sk = NULL;
 	rcu_read_unlock();
 	err = -ENOENT;
@@ -206,7 +206,7 @@ static int __udp_diag_destroy(struct sk_buff *in_skb,
 		return -EINVAL;
 	}
 
-	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
+	if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
 		sk = NULL;
 
 	rcu_read_unlock();