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net, vxlan: convert vxlan_sock.refcnt from atomic_t to refcount_t
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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>
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Reshetova, Elena authored and David S. Miller committed Jul 4, 2017
1 parent f00c854 commit 66af846
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Showing 2 changed files with 6 additions and 6 deletions.
10 changes: 5 additions & 5 deletions drivers/net/vxlan.c
Original file line number Diff line number Diff line change
Expand Up @@ -1034,11 +1034,11 @@ static bool vxlan_group_used(struct vxlan_net *vn, struct vxlan_dev *dev)
/* The vxlan_sock is only used by dev, leaving group has
* no effect on other vxlan devices.
*/
if (family == AF_INET && sock4 && atomic_read(&sock4->refcnt) == 1)
if (family == AF_INET && sock4 && refcount_read(&sock4->refcnt) == 1)
return false;
#if IS_ENABLED(CONFIG_IPV6)
sock6 = rtnl_dereference(dev->vn6_sock);
if (family == AF_INET6 && sock6 && atomic_read(&sock6->refcnt) == 1)
if (family == AF_INET6 && sock6 && refcount_read(&sock6->refcnt) == 1)
return false;
#endif

Expand Down Expand Up @@ -1075,7 +1075,7 @@ static bool __vxlan_sock_release_prep(struct vxlan_sock *vs)

if (!vs)
return false;
if (!atomic_dec_and_test(&vs->refcnt))
if (!refcount_dec_and_test(&vs->refcnt))
return false;

vn = net_generic(sock_net(vs->sock->sk), vxlan_net_id);
Expand Down Expand Up @@ -2825,7 +2825,7 @@ static struct vxlan_sock *vxlan_socket_create(struct net *net, bool ipv6,
}

vs->sock = sock;
atomic_set(&vs->refcnt, 1);
refcount_set(&vs->refcnt, 1);
vs->flags = (flags & VXLAN_F_RCV_FLAGS);

spin_lock(&vn->sock_lock);
Expand Down Expand Up @@ -2860,7 +2860,7 @@ static int __vxlan_sock_add(struct vxlan_dev *vxlan, bool ipv6)
spin_lock(&vn->sock_lock);
vs = vxlan_find_sock(vxlan->net, ipv6 ? AF_INET6 : AF_INET,
vxlan->cfg.dst_port, vxlan->cfg.flags);
if (vs && !atomic_add_unless(&vs->refcnt, 1, 0)) {
if (vs && !refcount_inc_not_zero(&vs->refcnt)) {
spin_unlock(&vn->sock_lock);
return -EBUSY;
}
Expand Down
2 changes: 1 addition & 1 deletion include/net/vxlan.h
Original file line number Diff line number Diff line change
Expand Up @@ -183,7 +183,7 @@ struct vxlan_sock {
struct hlist_node hlist;
struct socket *sock;
struct hlist_head vni_list[VNI_HASH_SIZE];
atomic_t refcnt;
refcount_t refcnt;
u32 flags;
};

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