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>
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index c267713..8b11341 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3844,7 +3844,7 @@ struct sk_buff *skb_clone_sk(struct sk_buff *skb)
struct sock *sk = skb->sk;
struct sk_buff *clone;
- if (!sk || !atomic_inc_not_zero(&sk->sk_refcnt))
+ if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return NULL;
clone = skb_clone(skb, GFP_ATOMIC);
@@ -3915,7 +3915,7 @@ void skb_complete_tx_timestamp(struct sk_buff *skb,
/* Take a reference to prevent skb_orphan() from freeing the socket,
* but only if the socket refcount is not zero.
*/
- if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) {
+ if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
*skb_hwtstamps(skb) = *hwtstamps;
__skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND, false);
sock_put(sk);
@@ -3997,7 +3997,7 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
/* Take a reference to prevent skb_orphan() from freeing the socket,
* but only if the socket refcount is not zero.
*/
- if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) {
+ if (likely(refcount_inc_not_zero(&sk->sk_refcnt))) {
err = sock_queue_err_skb(sk, skb);
sock_put(sk);
}
diff --git a/net/core/sock.c b/net/core/sock.c
index 0866d59..ba0ef6a 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1708,7 +1708,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
* (Documentation/RCU/rculist_nulls.txt for details)
*/
smp_wmb();
- atomic_set(&newsk->sk_refcnt, 2);
+ refcount_set(&newsk->sk_refcnt, 2);
/*
* Increment the counter in the same struct proto as the master
@@ -1851,7 +1851,7 @@ void skb_orphan_partial(struct sk_buff *skb)
) {
struct sock *sk = skb->sk;
- if (atomic_inc_not_zero(&sk->sk_refcnt)) {
+ if (refcount_inc_not_zero(&sk->sk_refcnt)) {
WARN_ON(refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc));
skb->destructor = sock_efree;
}
@@ -2687,7 +2687,7 @@ void sock_init_data(struct socket *sock, struct sock *sk)
* (Documentation/RCU/rculist_nulls.txt for details)
*/
smp_wmb();
- atomic_set(&sk->sk_refcnt, 1);
+ refcount_set(&sk->sk_refcnt, 1);
atomic_set(&sk->sk_drops, 0);
}
EXPORT_SYMBOL(sock_init_data);