Re: [RESEND PATCH v3 net-next] wireguard: allowedips: Add WGALLOWEDIP_F_REMOVE_ME flag

["Jason A. Donenfeld" <Jason@zx2c4.com>]

On Tue, May 20, 2025 at 11:47:56PM +0200, Jason A. Donenfeld wrote:
> Hi Jakub, Jordan,
> 
> On Sat, May 17, 2025 at 12:29:52PM -0700, Jordan Rife wrote:
> > * Use NLA_POLICY_MASK for WGALLOWEDIP_A_FLAGS validation (Jakub).
> [...]
> > +	[WGALLOWEDIP_A_FLAGS]		= NLA_POLICY_MASK(NLA_U32, __WGALLOWEDIP_F_ALL),
> 
> I wonder... Can we update, in a separate patch, these to also use
> NLA_POLICY_MASK?
> 
>    ...
>         [WGDEVICE_A_FLAGS]              = { .type = NLA_U32 },
>    ...
>         [WGPEER_A_FLAGS]                = { .type = NLA_U32 },
>    ...
> 
> Some consistency would be nice.

Perhaps I'll commit something like this?

From 22b6d15ad2a2e38bc80ebf65694106ff554b572f Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Tue, 20 May 2025 23:56:18 +0200
Subject: [PATCH] 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>
---
 drivers/net/wireguard/netlink.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index f7055180ba4a..b82266da949a 100644
--- a/drivers/net/wireguard/netlink.c
+++ b/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]		= { .type = 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]				= { .type = 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;
--
2.48.1