cifs: create a MD4 module and switch cifs.ko to use it

Ronnie Sahlberg · smfrench · commit 42c21973fa3c · 2021-08-25T15:48:00.000-05:00
MD4 support will likely be removed from the crypto directory, but
is needed for compression of NTLMSSP in SMB3 mounts.

Signed-off-by: Ronnie Sahlberg &lt;lsahlber@redhat.com&gt;
Signed-off-by: Steve French &lt;stfrench@microsoft.com&gt;
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
@@ -4,7 +4,6 @@ config CIFS
 	depends on INET
 	select NLS
 	select CRYPTO
-	select CRYPTO_MD4
 	select CRYPTO_MD5
 	select CRYPTO_SHA256
 	select CRYPTO_SHA512
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
@@ -1748,7 +1748,6 @@ MODULE_DESCRIPTION
 MODULE_VERSION(CIFS_VERSION);
 MODULE_SOFTDEP("ecb");
 MODULE_SOFTDEP("hmac");
-MODULE_SOFTDEP("md4");
 MODULE_SOFTDEP("md5");
 MODULE_SOFTDEP("nls");
 MODULE_SOFTDEP("aes");
diff --git a/fs/cifs/smbencrypt.c b/fs/cifs/smbencrypt.c
@@ -24,6 +24,7 @@
 #include "cifsglob.h"
 #include "cifs_debug.h"
 #include "cifsproto.h"
+#include "../cifs_common/md4.h"
 
 #ifndef false
 #define false 0
@@ -42,29 +43,24 @@ static int
 mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
 {
 	int rc;
-	struct crypto_shash *md4 = NULL;
-	struct sdesc *sdescmd4 = NULL;
+	struct md4_ctx mctx;
 
-	rc = cifs_alloc_hash("md4", &md4, &sdescmd4);
-	if (rc)
-		goto mdfour_err;
-
-	rc = crypto_shash_init(&sdescmd4->shash);
+	rc = cifs_md4_init(&mctx);
 	if (rc) {
-		cifs_dbg(VFS, "%s: Could not init md4 shash\n", __func__);
+		cifs_dbg(VFS, "%s: Could not init MD4\n", __func__);
 		goto mdfour_err;
 	}
-	rc = crypto_shash_update(&sdescmd4->shash, link_str, link_len);
+	rc = cifs_md4_update(&mctx, link_str, link_len);
 	if (rc) {
-		cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
+		cifs_dbg(VFS, "%s: Could not update MD4\n", __func__);
 		goto mdfour_err;
 	}
-	rc = crypto_shash_final(&sdescmd4->shash, md4_hash);
+	rc = cifs_md4_final(&mctx, md4_hash);
 	if (rc)
-		cifs_dbg(VFS, "%s: Could not generate md4 hash\n", __func__);
+		cifs_dbg(VFS, "%s: Could not finalize MD4\n", __func__);
+
 
 mdfour_err:
-	cifs_free_hash(&md4, &sdescmd4);
 	return rc;
 }
 
diff --git a/fs/cifs_common/Makefile b/fs/cifs_common/Makefile
@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_CIFS_COMMON) += cifs_arc4.o
+obj-$(CONFIG_CIFS_COMMON) += cifs_md4.o
diff --git a/fs/cifs_common/cifs_md4.c b/fs/cifs_common/cifs_md4.c
@@ -0,0 +1,201 @@
+/*
+ * Cryptographic API.
+ *
+ * MD4 Message Digest Algorithm (RFC1320).
+ *
+ * Implementation derived from Andrew Tridgell and Steve French's
+ * CIFS MD4 implementation, and the cryptoapi implementation
+ * originally based on the public domain implementation written
+ * by Colin Plumb in 1993.
+ *
+ * Copyright (c) Andrew Tridgell 1997-1998.
+ * Modified by Steve French (sfrench@us.ibm.com) 2002
+ * Copyright (c) Cryptoapi developers.
+ * Copyright (c) 2002 David S. Miller (davem@redhat.com)
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+#include "md4.h"
+
+MODULE_LICENSE("GPL");
+
+static inline u32 lshift(u32 x, unsigned int s)
+{
+	x &= 0xFFFFFFFF;
+	return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
+}
+
+static inline u32 F(u32 x, u32 y, u32 z)
+{
+	return (x & y) | ((~x) & z);
+}
+
+static inline u32 G(u32 x, u32 y, u32 z)
+{
+	return (x & y) | (x & z) | (y & z);
+}
+
+static inline u32 H(u32 x, u32 y, u32 z)
+{
+	return x ^ y ^ z;
+}
+
+#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))
+#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (u32)0x5A827999,s))
+#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (u32)0x6ED9EBA1,s))
+
+static void md4_transform(u32 *hash, u32 const *in)
+{
+	u32 a, b, c, d;
+
+	a = hash[0];
+	b = hash[1];
+	c = hash[2];
+	d = hash[3];
+
+	ROUND1(a, b, c, d, in[0], 3);
+	ROUND1(d, a, b, c, in[1], 7);
+	ROUND1(c, d, a, b, in[2], 11);
+	ROUND1(b, c, d, a, in[3], 19);
+	ROUND1(a, b, c, d, in[4], 3);
+	ROUND1(d, a, b, c, in[5], 7);
+	ROUND1(c, d, a, b, in[6], 11);
+	ROUND1(b, c, d, a, in[7], 19);
+	ROUND1(a, b, c, d, in[8], 3);
+	ROUND1(d, a, b, c, in[9], 7);
+	ROUND1(c, d, a, b, in[10], 11);
+	ROUND1(b, c, d, a, in[11], 19);
+	ROUND1(a, b, c, d, in[12], 3);
+	ROUND1(d, a, b, c, in[13], 7);
+	ROUND1(c, d, a, b, in[14], 11);
+	ROUND1(b, c, d, a, in[15], 19);
+
+	ROUND2(a, b, c, d, in[0], 3);
+	ROUND2(d, a, b, c, in[4], 5);
+	ROUND2(c, d, a, b, in[8], 9);
+	ROUND2(b, c, d, a, in[12], 13);
+	ROUND2(a, b, c, d, in[1], 3);
+	ROUND2(d, a, b, c, in[5], 5);
+	ROUND2(c, d, a, b, in[9], 9);
+	ROUND2(b, c, d, a, in[13], 13);
+	ROUND2(a, b, c, d, in[2], 3);
+	ROUND2(d, a, b, c, in[6], 5);
+	ROUND2(c, d, a, b, in[10], 9);
+	ROUND2(b, c, d, a, in[14], 13);
+	ROUND2(a, b, c, d, in[3], 3);
+	ROUND2(d, a, b, c, in[7], 5);
+	ROUND2(c, d, a, b, in[11], 9);
+	ROUND2(b, c, d, a, in[15], 13);
+
+	ROUND3(a, b, c, d, in[0], 3);
+	ROUND3(d, a, b, c, in[8], 9);
+	ROUND3(c, d, a, b, in[4], 11);
+	ROUND3(b, c, d, a, in[12], 15);
+	ROUND3(a, b, c, d, in[2], 3);
+	ROUND3(d, a, b, c, in[10], 9);
+	ROUND3(c, d, a, b, in[6], 11);
+	ROUND3(b, c, d, a, in[14], 15);
+	ROUND3(a, b, c, d, in[1], 3);
+	ROUND3(d, a, b, c, in[9], 9);
+	ROUND3(c, d, a, b, in[5], 11);
+	ROUND3(b, c, d, a, in[13], 15);
+	ROUND3(a, b, c, d, in[3], 3);
+	ROUND3(d, a, b, c, in[11], 9);
+	ROUND3(c, d, a, b, in[7], 11);
+	ROUND3(b, c, d, a, in[15], 15);
+
+	hash[0] += a;
+	hash[1] += b;
+	hash[2] += c;
+	hash[3] += d;
+}
+
+static inline void md4_transform_helper(struct md4_ctx *ctx)
+{
+	le32_to_cpu_array(ctx->block, ARRAY_SIZE(ctx->block));
+	md4_transform(ctx->hash, ctx->block);
+}
+
+int cifs_md4_init(struct md4_ctx *mctx)
+{
+	memset(mctx, 0, sizeof(struct md4_ctx));
+	mctx->hash[0] = 0x67452301;
+	mctx->hash[1] = 0xefcdab89;
+	mctx->hash[2] = 0x98badcfe;
+	mctx->hash[3] = 0x10325476;
+	mctx->byte_count = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cifs_md4_init);
+
+int cifs_md4_update(struct md4_ctx *mctx, const u8 *data, unsigned int len)
+{
+	const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
+
+	mctx->byte_count += len;
+
+	if (avail > len) {
+		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
+		       data, len);
+		return 0;
+	}
+
+	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
+	       data, avail);
+
+	md4_transform_helper(mctx);
+	data += avail;
+	len -= avail;
+
+	while (len >= sizeof(mctx->block)) {
+		memcpy(mctx->block, data, sizeof(mctx->block));
+		md4_transform_helper(mctx);
+		data += sizeof(mctx->block);
+		len -= sizeof(mctx->block);
+	}
+
+	memcpy(mctx->block, data, len);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cifs_md4_update);
+
+int cifs_md4_final(struct md4_ctx *mctx, u8 *out)
+{
+	const unsigned int offset = mctx->byte_count & 0x3f;
+	char *p = (char *)mctx->block + offset;
+	int padding = 56 - (offset + 1);
+
+	*p++ = 0x80;
+	if (padding < 0) {
+		memset(p, 0x00, padding + sizeof(u64));
+		md4_transform_helper(mctx);
+		p = (char *)mctx->block;
+		padding = 56;
+	}
+
+	memset(p, 0, padding);
+	mctx->block[14] = mctx->byte_count << 3;
+	mctx->block[15] = mctx->byte_count >> 29;
+	le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
+			  sizeof(u64)) / sizeof(u32));
+	md4_transform(mctx->hash, mctx->block);
+	cpu_to_le32_array(mctx->hash, ARRAY_SIZE(mctx->hash));
+	memcpy(out, mctx->hash, sizeof(mctx->hash));
+	memset(mctx, 0, sizeof(*mctx));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(cifs_md4_final);
diff --git a/fs/cifs_common/md4.h b/fs/cifs_common/md4.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Common values for ARC4 Cipher Algorithm
+ */
+
+#ifndef _CIFS_MD4_H
+#define _CIFS_MD4_H
+
+#include <linux/types.h>
+
+#define MD4_DIGEST_SIZE		16
+#define MD4_HMAC_BLOCK_SIZE	64
+#define MD4_BLOCK_WORDS		16
+#define MD4_HASH_WORDS		4
+
+struct md4_ctx {
+	u32 hash[MD4_HASH_WORDS];
+	u32 block[MD4_BLOCK_WORDS];
+	u64 byte_count;
+};
+
+
+int cifs_md4_init(struct md4_ctx *mctx);
+int cifs_md4_update(struct md4_ctx *mctx, const u8 *data, unsigned int len);
+int cifs_md4_final(struct md4_ctx *mctx, u8 *out);
+
+#endif /* _CIFS_MD4_H */

Original file line number	Diff line number	Diff line change
`@@ -4,3 +4,4 @@`
`4`	`4`	`#`
`5`	`5`
`6`	`6`	`obj-$(CONFIG_CIFS_COMMON) += cifs_arc4.o`
	`7`	`+obj-$(CONFIG_CIFS_COMMON) += cifs_md4.o`