From: Guillem Jover <guillem@hadrons.org>
Date: Sat, 26 Jul 2025 10:41:23 +0000 (+0200)
Subject: Mark tau and sigma Chacha variables as nonstring
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=HEAD;p=thirdparty%2Flibbsd.git

Mark tau and sigma Chacha variables as nonstring

These contain a sequence of bytes, and are not a NUL-terminated string.
Help the compiler understand the intent of the code.
---

diff --git a/src/chacha_private.h b/src/chacha_private.h
index ef1b931..97e9020 100644
--- a/src/chacha_private.h
+++ b/src/chacha_private.h
@@ -48,8 +48,16 @@ typedef struct
   a = PLUS(a,b); d = ROTATE(XOR(d,a), 8); \
   c = PLUS(c,d); b = ROTATE(XOR(b,c), 7);
 
-static const char sigma[16] = "expand 32-byte k";
-static const char tau[16] = "expand 16-byte k";
+#if defined(__has_attribute)
+#if __has_attribute(__nonstring__)
+#define ATTRIBUTE_NONSTRING __attribute__((__nonstring__))
+#else
+#define ATTRIBUTE_NONSTRING
+#endif
+#endif
+
+static const char sigma[16] ATTRIBUTE_NONSTRING = "expand 32-byte k";
+static const char tau[16] ATTRIBUTE_NONSTRING = "expand 16-byte k";
 
 static void
 chacha_keysetup(chacha_ctx *x,const u8 *k,u32 kbits)