wireguard: netlink: use NLA_POLICY_MASK where possible

JIRA: https://issues.redhat.com/browse/RHEL-96621

commit c852902
Author: Jason A. Donenfeld <Jason@zx2c4.com>
Date:   Wed May 21 23:27:05 2025 +0200

    wireguard: netlink: use NLA_POLICY_MASK where possible

    Rather than manually validating flags against the various __ALL_*
    constants, put this in the netlink policy description and have the upper
    layer machinery check it for us.

    Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
    Link: https://patch.msgid.link/20250521212707.1767879-4-Jason@zx2c4.com
    Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Signed-off-by: CKI Backport Bot <cki-ci-bot+cki-gitlab-backport-bot@redhat.com>

Author: CKI Backport Bot

drivers/net/wireguard/netlink.c

@@ -24,7 +24,7 @@ static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = {
 	[WGDEVICE_A_IFNAME]		= { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
 	[WGDEVICE_A_PRIVATE_KEY]	= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
 	[WGDEVICE_A_PUBLIC_KEY]		= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
-	[WGDEVICE_A_FLAGS]		= { .type = NLA_U32 },
+	[WGDEVICE_A_FLAGS]		= NLA_POLICY_MASK(NLA_U32, __WGDEVICE_F_ALL),
 	[WGDEVICE_A_LISTEN_PORT]	= { .type = NLA_U16 },
 	[WGDEVICE_A_FWMARK]		= { .type = NLA_U32 },
 	[WGDEVICE_A_PEERS]		= { .type = NLA_NESTED }
@@ -33,7 +33,7 @@ static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = {
 static const struct nla_policy peer_policy[WGPEER_A_MAX + 1] = {
 	[WGPEER_A_PUBLIC_KEY]				= NLA_POLICY_EXACT_LEN(NOISE_PUBLIC_KEY_LEN),
 	[WGPEER_A_PRESHARED_KEY]			= NLA_POLICY_EXACT_LEN(NOISE_SYMMETRIC_KEY_LEN),
-	[WGPEER_A_FLAGS]				= { .type = NLA_U32 },
+	[WGPEER_A_FLAGS]				= NLA_POLICY_MASK(NLA_U32, __WGPEER_F_ALL),
 	[WGPEER_A_ENDPOINT]				= NLA_POLICY_MIN_LEN(sizeof(struct sockaddr)),
 	[WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL]	= { .type = NLA_U16 },
 	[WGPEER_A_LAST_HANDSHAKE_TIME]			= NLA_POLICY_EXACT_LEN(sizeof(struct __kernel_timespec)),
@@ -373,9 +373,6 @@ static int set_peer(struct wg_device *wg, struct nlattr **attrs)
 
 	if (attrs[WGPEER_A_FLAGS])
 		flags = nla_get_u32(attrs[WGPEER_A_FLAGS]);
-	ret = -EOPNOTSUPP;
-	if (flags & ~__WGPEER_F_ALL)
-		goto out;
 
 	ret = -EPFNOSUPPORT;
 	if (attrs[WGPEER_A_PROTOCOL_VERSION]) {
@@ -506,9 +503,6 @@ static int wg_set_device(struct sk_buff *skb, struct genl_info *info)
 
 	if (info->attrs[WGDEVICE_A_FLAGS])
 		flags = nla_get_u32(info->attrs[WGDEVICE_A_FLAGS]);
-	ret = -EOPNOTSUPP;
-	if (flags & ~__WGDEVICE_F_ALL)
-		goto out;
 
 	if (info->attrs[WGDEVICE_A_LISTEN_PORT] || info->attrs[WGDEVICE_A_FWMARK]) {
 		struct net *net;