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Subject[PATCH 04/36] net, vxlan: convert vxlan_sock.refcnt from atomic_t to refcount_t
Date
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>
---
drivers/net/vxlan.c | 10 +++++-----
include/net/vxlan.h | 2 +-
2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index b04e103..96aa7e6 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -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

@@ -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);
@@ -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);
@@ -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;
}
diff --git a/include/net/vxlan.h b/include/net/vxlan.h
index 326e849..3f430e3 100644
--- a/include/net/vxlan.h
+++ b/include/net/vxlan.h
@@ -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;
};

--
2.7.4
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