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Date: Thu, 7 Feb 2008 15:13:53 +0300
To: Dmitry Stogov <dmitry@zend.com>
Cc: Sara Golemon <saramg_76@yahoo.com>, Stanislav Malyshev <stas@zend.com>,
	Andi Gutmans <andi@zend.com>,
	PHP Internals List <internals@lists.php.net>
Message-ID: <20080207121353.GA11906@openwall.com>
References: <20071209010552.GA12561@openwall.com> <47A849D0.8050508@zend.com> <20080205235055.GA19309@openwall.com> <47AAD95A.8010109@zend.com> <20080207112109.GA30558@openwall.com> <20080207115027.GA30811@openwall.com>
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Subject: untie the MD4 code from MD5 (was: faster & public domain MD5 implementation)
From: solar@openwall.com (Solar Designer)

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I wrote:
> OK, I think I found it.  ext/hash/php_hash_md.h has this:
> 
> #define PHP_MD4Init                     PHP_MD5Init
> 
> which breaks when the two implementations are not that similar anymore.
> Replacing the MD4 implementation with mine as well would fix this (or
> hide the bug, depending on your point of view), but for now I think the
> right fix would be to define a PHP_MD4Init() function explicitly.

The patch is attached.  It contains two other tiny changes:

1. Replaces two of MD4's basic functions with more optimal versions
(faster and smaller code).

2. Corrects a typo in a nearby comment.

This patch may be applied independently and before the MD5 replacement
patch - but it is required for the MD5 replacement patch.

Alexander

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--- php-5.2.5/ext/hash/hash_md.c.orig	2007-01-09 01:29:25 +0300
+++ php-5.2.5/ext/hash/hash_md.c	2008-02-07 14:58:03 +0300
@@ -442,8 +442,8 @@ const unsigned char block[64];
 
 /* MD4 */
 
-#define MD4_F(x,y,z)			(((x) & (y)) | ((~(x)) & (z)))
-#define MD4_G(x,y,z)			(((x) & (y)) | ((x) & (z)) | ((y) & (z)))
+#define MD4_F(x,y,z)			((z) ^ ((x) & ((y) ^ (z))))
+#define MD4_G(x,y,z)			(((x) & ((y) | (z))) | ((y) & (z)))
 #define MD4_H(x,y,z)			((x) ^ (y) ^ (z))
 
 #define ROTL32(s,v)				(((v) << (s)) | ((v) >> (32 - (s))))
@@ -518,8 +518,23 @@ static void MD4Transform(php_hash_uint32
 	state[3] += d;
 }
 
+/* {{{ PHP_MD4Init
+ * MD4 initialization. Begins an MD4 operation, writing a new context.
+ */
+PHP_HASH_API void PHP_MD4Init(PHP_MD4_CTX * context)
+{
+	context->count[0] = context->count[1] = 0;
+	/* Load magic initialization constants.
+	 */
+	context->state[0] = 0x67452301;
+	context->state[1] = 0xefcdab89;
+	context->state[2] = 0x98badcfe;
+	context->state[3] = 0x10325476;
+}
+/* }}} */
+
 /* {{{ PHP_MD4Update
-   MD4 block update operation. Continues an MD5 message-digest
+   MD4 block update operation. Continues an MD4 message-digest
    operation, processing another message block, and updating the
    context.
  */
--- php-5.2.5/ext/hash/php_hash_md.h.orig	2007-01-01 12:36:01 +0300
+++ php-5.2.5/ext/hash/php_hash_md.h	2008-02-07 14:58:35 +0300
@@ -81,7 +81,7 @@
 	unsigned char buffer[64];
 } PHP_MD4_CTX;
 
-#define PHP_MD4Init			PHP_MD5Init
+PHP_HASH_API void PHP_MD4Init(PHP_MD4_CTX *);
 PHP_HASH_API void PHP_MD4Update(PHP_MD4_CTX *context, const unsigned char *, unsigned int);
 PHP_HASH_API void PHP_MD4Final(unsigned char[16], PHP_MD4_CTX *);
 

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