Merge branch 'wireguard-fixes-for-6-5-rc6'

Jason A. Donenfeld says:

====================
wireguard fixes for 6.5-rc6

Just one patch this time, somewhat late in the cycle:

1) Fix an off-by-one calculation for the maximum node depth size in the
   allowedips trie data structure, and also adjust the self-tests to hit
   this case so it doesn't regress again in the future.
====================

Link: https://lore.kernel.org/r/20230807132146.2191597-1-Jason@zx2c4.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 14 insertions, 10 deletions

diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
index 5bf7822c53f1..0ba714ca5185 100644
--- a/drivers/net/wireguard/allowedips.c
+++ b/drivers/net/wireguard/allowedips.c
@@ -6,7 +6,7 @@
 #include "allowedips.h"
 #include "peer.h"
 
-enum { MAX_ALLOWEDIPS_BITS = 128 };
+enum { MAX_ALLOWEDIPS_DEPTH = 129 };
 
 static struct kmem_cache *node_cache;
 
@@ -42,7 +42,7 @@ static void push_rcu(struct allowedips_node **stack,
 		     struct allowedips_node __rcu *p, unsigned int *len)
 {
 	if (rcu_access_pointer(p)) {
-		if (WARN_ON(IS_ENABLED(DEBUG) && *len >= MAX_ALLOWEDIPS_BITS))
+		if (WARN_ON(IS_ENABLED(DEBUG) && *len >= MAX_ALLOWEDIPS_DEPTH))
 			return;
 		stack[(*len)++] = rcu_dereference_raw(p);
 	}
@@ -55,7 +55,7 @@ static void node_free_rcu(struct rcu_head *rcu)
 
 static void root_free_rcu(struct rcu_head *rcu)
 {
-	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_BITS] = {
+	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = {
 		container_of(rcu, struct allowedips_node, rcu) };
 	unsigned int len = 1;
 
@@ -68,7 +68,7 @@ static void root_free_rcu(struct rcu_head *rcu)
 
 static void root_remove_peer_lists(struct allowedips_node *root)
 {
-	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_BITS] = { root };
+	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = { root };
 	unsigned int len = 1;
 
 	while (len > 0 && (node = stack[--len])) {
diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c
index 78ebe2892a78..3d1f64ff2e12 100644
--- a/drivers/net/wireguard/selftest/allowedips.c
+++ b/drivers/net/wireguard/selftest/allowedips.c
@@ -593,16 +593,20 @@ bool __init wg_allowedips_selftest(void)
 	wg_allowedips_remove_by_peer(&t, a, &mutex);
 	test_negative(4, a, 192, 168, 0, 1);
 
-	/* These will hit the WARN_ON(len >= MAX_ALLOWEDIPS_BITS) in free_node
+	/* These will hit the WARN_ON(len >= MAX_ALLOWEDIPS_DEPTH) in free_node
 	 * if something goes wrong.
 	 */
-	for (i = 0; i < MAX_ALLOWEDIPS_BITS; ++i) {
-		part = cpu_to_be64(~(1LLU << (i % 64)));
-		memset(&ip, 0xff, 16);
-		memcpy((u8 *)&ip + (i < 64) * 8, &part, 8);
+	for (i = 0; i < 64; ++i) {
+		part = cpu_to_be64(~0LLU << i);
+		memset(&ip, 0xff, 8);
+		memcpy((u8 *)&ip + 8, &part, 8);
+		wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex);
+		memcpy(&ip, &part, 8);
+		memset((u8 *)&ip + 8, 0, 8);
 		wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex);
 	}
-
+	memset(&ip, 0, 16);
+	wg_allowedips_insert_v6(&t, &ip, 128, a, &mutex);
 	wg_allowedips_free(&t, &mutex);
 
 	wg_allowedips_init(&t);