From 58af720072b1e4edc5d7e726728486a1c91af1b3 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Sun, 15 Oct 2017 21:29:01 +0200
Subject: tools: encoding: be more paranoid

Needless, but overkill can be fun.
---
 src/tools/encoding.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/tools/encoding.c b/src/tools/encoding.c
index 3d5e94b..c407b57 100644
--- a/src/tools/encoding.c
+++ b/src/tools/encoding.c
@@ -102,10 +102,10 @@ bool key_from_hex(uint8_t key[static WG_KEY_LEN], const char *hex)
 
 bool key_is_zero(const uint8_t key[static WG_KEY_LEN])
 {
-	uint8_t acc = 0;
+	volatile uint8_t acc = 0;
 	for (unsigned int i = 0; i < WG_KEY_LEN; ++i) {
 		acc |= key[i];
 		__asm__ ("" : "=r" (acc) : "0" (acc));
 	}
-	return acc == 0;
+	return 1 & ((acc - 1) >> 8);
 }
-- 
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