From 890ac460b0e81ef235c2cfaf8c260799d2571ce2 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Mon, 7 Aug 2023 15:21:27 +0200
Subject: [PATCH] wireguard: allowedips: expand maximum node depth

commit 46622219aae2b67813fe31a7b8cb7da5baff5c8a upstream.

In the allowedips self-test, nodes are inserted into the tree, but it
generated an even amount of nodes, but for checking maximum node depth,
there is of course the root node, which makes the total number
necessarily odd. With two few nodes added, it never triggered the
maximum depth check like it should have. So, add 129 nodes instead of
128 nodes, and do so with a more straightforward scheme, starting with
all the bits set, and shifting over one each time. Then increase the
maximum depth to 129, and choose a better name for that variable to
make it clear that it represents depth as opposed to bits.

Cc: stable@vger.kernel.org
Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20230807132146.2191597-2-Jason@zx2c4.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/wireguard/allowedips.c          |  8 ++++----
 drivers/net/wireguard/selftest/allowedips.c | 16 ++++++++++------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
index 5bf7822c53f18..0ba714ca5185c 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 41db10f9be498..2c9eec24eec45 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);
-- 
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