wireguard: netlink: use WG_KEY_LEN in policies

When converting the netlink policies to YNL, the constants used
in the policy have to be visible to userspace.

As NOISE_*_KEY_LEN isn't visible to userspace, change the policy
to use WG_KEY_LEN, as also documented in the UAPI header:

$ grep WG_KEY_LEN include/uapi/linux/wireguard.h
 *    WGDEVICE_A_PRIVATE_KEY: NLA_EXACT_LEN, len WG_KEY_LEN
 *    WGDEVICE_A_PUBLIC_KEY: NLA_EXACT_LEN, len WG_KEY_LEN
 *            WGPEER_A_PUBLIC_KEY: NLA_EXACT_LEN, len WG_KEY_LEN
 *            WGPEER_A_PRESHARED_KEY: NLA_EXACT_LEN, len WG_KEY_LEN
 [...]

Add a couple of BUILD_BUG_ON() to ensure that they stay in sync.

No behavioural changes intended.

Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

diff --git a/drivers/net/wireguard/netlink.c b/drivers/net/wireguard/netlink.c
index 97723f9c7998f525d812df4bb309a9e7e8cfd3a8..682678d24a9f6ef327b56c6f4b1841077e1471b9 100644 (file)
--- a/drivers/net/wireguard/netlink.c
+++ b/drivers/net/wireguard/netlink.c
@@ -24,8 +24,8 @@ static const struct nla_policy allowedip_policy[WGALLOWEDIP_A_MAX + 1];
 static const struct nla_policy device_policy[WGDEVICE_A_MAX + 1] = {
        [WGDEVICE_A_IFINDEX]            = { .type = NLA_U32 },
        [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_PRIVATE_KEY]        = NLA_POLICY_EXACT_LEN(WG_KEY_LEN),
+       [WGDEVICE_A_PUBLIC_KEY]         = NLA_POLICY_EXACT_LEN(WG_KEY_LEN),
        [WGDEVICE_A_FLAGS]              = NLA_POLICY_MASK(NLA_U32, __WGDEVICE_F_ALL),
        [WGDEVICE_A_LISTEN_PORT]        = { .type = NLA_U16 },
        [WGDEVICE_A_FWMARK]             = { .type = NLA_U32 },
@@ -33,8 +33,8 @@ 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_PUBLIC_KEY]                           = NLA_POLICY_EXACT_LEN(WG_KEY_LEN),
+       [WGPEER_A_PRESHARED_KEY]                        = NLA_POLICY_EXACT_LEN(WG_KEY_LEN),
        [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 },
@@ -643,6 +643,9 @@ static struct genl_family genl_family __ro_after_init = {
 
 int __init wg_genetlink_init(void)
 {
+       BUILD_BUG_ON(WG_KEY_LEN != NOISE_PUBLIC_KEY_LEN);
+       BUILD_BUG_ON(WG_KEY_LEN != NOISE_SYMMETRIC_KEY_LEN);
+
        return genl_register_family(&genl_family);
 }