allowedips: swap endianness early on

Otherwise if gcc's optimizer is able to look far in but not overly far
in, we wind up with "warning: 'key' may be used uninitialized in this
function [-Wmaybe-uninitialized]".

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/src/allowedips.c b/src/allowedips.c
index be0fbab..8699fb1 100644
--- a/src/allowedips.c
+++ b/src/allowedips.c
@@ -242,17 +242,14 @@ node_placement(struct allowedips_node __rcu *trie, const u8 *key, u8 cidr,
 	return exact;
 }
 
-static int add(struct allowedips_node __rcu **trie, u8 bits, const u8 *be_key,
+static int add(struct allowedips_node __rcu **trie, u8 bits, const u8 *key,
 	       u8 cidr, struct wg_peer *peer, struct mutex *lock)
 {
 	struct allowedips_node *node, *parent, *down, *newnode;
-	u8 key[16] __aligned(__alignof(u64));
 
 	if (unlikely(cidr > bits || !peer))
 		return -EINVAL;
 
-	swap_endian(key, be_key, bits);
-
 	if (!rcu_access_pointer(*trie)) {
 		node = kzalloc(sizeof(*node), GFP_KERNEL);
 		if (unlikely(!node))
@@ -336,16 +333,22 @@ int wg_allowedips_insert_v4(struct allowedips *table, const struct in_addr *ip,
 			    u8 cidr, struct wg_peer *peer,
 			    struct mutex *lock)
 {
+	u8 key[4] __aligned(__alignof(u32));
+
 	++table->seq;
-	return add(&table->root4, 32, (const u8 *)ip, cidr, peer, lock);
+	swap_endian(key, (const u8 *)ip, 32);
+	return add(&table->root4, 32, key, cidr, peer, lock);
 }
 
 int wg_allowedips_insert_v6(struct allowedips *table, const struct in6_addr *ip,
 			    u8 cidr, struct wg_peer *peer,
 			    struct mutex *lock)
 {
+	u8 key[16] __aligned(__alignof(u64));
+
 	++table->seq;
-	return add(&table->root6, 128, (const u8 *)ip, cidr, peer, lock);
+	swap_endian(key, (const u8 *)ip, 128);
+	return add(&table->root6, 128, key, cidr, peer, lock);
 }
 
 void wg_allowedips_remove_by_peer(struct allowedips *table,