util/nvmutil: improved entropy in fallback_rand

Signed-off-by: Leah Rowe <leah@libreboot.org>
2026-07-11 05:52:36 +02:00 · 2026-03-12 14:32:46 +00:00
parent 1cee54ee2b
commit 38c3889f67
1 changed files with 8 additions and 0 deletions
@@ -1036,6 +1036,14 @@ fallback_rand(void)
 	    ^ (unsigned long)&mix
 	    ^ counter++;

+	/*
+	 * Stack addresses can vary between
+	 * calls, thus increasing entropy.
+	 */
+	mix ^= (unsigned long)&mix;
+	mix ^= (unsigned long)&tv;
+	mix ^= (unsigned long)&counter;
+
 	return (uint16_t)(mix & 0xf);
 }