net: convert unix_address.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.

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>

1 files changed, 4 insertions, 4 deletions

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index c88525403d2e..b9ee766054f6 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -212,7 +212,7 @@ EXPORT_SYMBOL_GPL(unix_peer_get);
 
 static inline void unix_release_addr(struct unix_address *addr)
 {
-        if (atomic_dec_and_test(&addr->refcnt))
+        if (refcount_dec_and_test(&addr->refcnt))
                 kfree(addr);
 }
 
@@ -864,7 +864,7 @@ static int unix_autobind(struct socket *sock)
                 goto out;
 
         addr->name->sun_family = AF_UNIX;
-        atomic_set(&addr->refcnt, 1);
+        refcount_set(&addr->refcnt, 1);
 
 retry:
         addr->len = sprintf(addr->name->sun_path+1, "%05x", ordernum) + 1 + sizeof(short);
@@ -1040,7 +1040,7 @@ static int unix_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
         memcpy(addr->name, sunaddr, addr_len);
         addr->len = addr_len;
         addr->hash = hash ^ sk->sk_type;
-        atomic_set(&addr->refcnt, 1);
+        refcount_set(&addr->refcnt, 1);
 
         if (sun_path[0]) {
                 addr->hash = UNIX_HASH_SIZE;
@@ -1335,7 +1335,7 @@ restart:
 
         /* copy address information from listening to new sock*/
         if (otheru->addr) {
-                atomic_inc(&otheru->addr->refcnt);
+                refcount_inc(&otheru->addr->refcnt);
                 newu->addr = otheru->addr;
         }
         if (otheru->path.dentry) {