path: root/drivers/net/wireguard/selftest/allowedips.c
diff options
authorJason A. Donenfeld <Jason@zx2c4.com>2022-08-02 14:56:12 +0200
committerJakub Kicinski <kuba@kernel.org>2022-08-02 13:47:50 -0700
commitc31b14d86dfe7174361e8c6e5df6c2c3a4d5918c (patch)
treeb0534543570abe674a6e28be6ce9dee2a103f212 /drivers/net/wireguard/selftest/allowedips.c
parentwireguard: selftests: update config fragments (diff)
wireguard: allowedips: don't corrupt stack when detecting overflow
In case push_rcu() and related functions are buggy, there's a WARN_ON(len >= 128), which the selftest tries to hit by being tricky. In case it is hit, we shouldn't corrupt the kernel's stack, though; otherwise it may be hard to even receive the report that it's buggy. So conditionalize the stack write based on that WARN_ON()'s return value. Note that this never *actually* happens anyway. The WARN_ON() in the first place is bounded by IS_ENABLED(DEBUG), and isn't expected to ever actually hit. This is just a debugging sanity check. Additionally, hoist the constant 128 into a named enum, MAX_ALLOWEDIPS_BITS, so that it's clear why this value is chosen. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/all/CAHk-=wjJZGA6w_DxA+k7Ejbqsq+uGK==koPai3sqdsfJqemvag@mail.gmail.com/ Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to '')
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/net/wireguard/selftest/allowedips.c b/drivers/net/wireguard/selftest/allowedips.c
index e173204ae7d7..41db10f9be49 100644
--- a/drivers/net/wireguard/selftest/allowedips.c
+++ b/drivers/net/wireguard/selftest/allowedips.c
@@ -593,10 +593,10 @@ 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 >= 128) in free_node if something
- * goes wrong.
+ /* These will hit the WARN_ON(len >= MAX_ALLOWEDIPS_BITS) in free_node
+ * if something goes wrong.
- for (i = 0; i < 128; ++i) {
+ 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);