linux/fs/cifs/smbencrypt.c
Ard Biesheuvel 9a394d1208 fs: cifs: move from the crypto cipher API to the new DES library interface
Some legacy code in the CIFS driver uses single DES to calculate
some password hash, and uses the crypto cipher API to do so. Given
that there is no point in invoking an accelerated cipher for doing
56-bit symmetric encryption on a single 8-byte block of input, the
flexibility of the crypto cipher API does not add much value here,
and so we're much better off using a library call into the generic
C implementation.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-08-22 14:57:34 +10:00

211 lines
4.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
Unix SMB/Netbios implementation.
Version 1.9.
SMB parameters and setup
Copyright (C) Andrew Tridgell 1992-2000
Copyright (C) Luke Kenneth Casson Leighton 1996-2000
Modified by Jeremy Allison 1995.
Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
Modified by Steve French (sfrench@us.ibm.com) 2002-2003
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/fips.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/random.h>
#include <crypto/des.h>
#include "cifs_fs_sb.h"
#include "cifs_unicode.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifs_debug.h"
#include "cifsproto.h"
#ifndef false
#define false 0
#endif
#ifndef true
#define true 1
#endif
/* following came from the other byteorder.h to avoid include conflicts */
#define CVAL(buf,pos) (((unsigned char *)(buf))[pos])
#define SSVALX(buf,pos,val) (CVAL(buf,pos)=(val)&0xFF,CVAL(buf,pos+1)=(val)>>8)
#define SSVAL(buf,pos,val) SSVALX((buf),(pos),((__u16)(val)))
static void
str_to_key(unsigned char *str, unsigned char *key)
{
int i;
key[0] = str[0] >> 1;
key[1] = ((str[0] & 0x01) << 6) | (str[1] >> 2);
key[2] = ((str[1] & 0x03) << 5) | (str[2] >> 3);
key[3] = ((str[2] & 0x07) << 4) | (str[3] >> 4);
key[4] = ((str[3] & 0x0F) << 3) | (str[4] >> 5);
key[5] = ((str[4] & 0x1F) << 2) | (str[5] >> 6);
key[6] = ((str[5] & 0x3F) << 1) | (str[6] >> 7);
key[7] = str[6] & 0x7F;
for (i = 0; i < 8; i++)
key[i] = (key[i] << 1);
}
static int
smbhash(unsigned char *out, const unsigned char *in, unsigned char *key)
{
unsigned char key2[8];
struct des_ctx ctx;
str_to_key(key, key2);
if (fips_enabled) {
cifs_dbg(VFS, "FIPS compliance enabled: DES not permitted\n");
return -ENOENT;
}
des_expand_key(&ctx, key2, DES_KEY_SIZE);
des_encrypt(&ctx, out, in);
memzero_explicit(&ctx, sizeof(ctx));
return 0;
}
static int
E_P16(unsigned char *p14, unsigned char *p16)
{
int rc;
unsigned char sp8[8] =
{ 0x4b, 0x47, 0x53, 0x21, 0x40, 0x23, 0x24, 0x25 };
rc = smbhash(p16, sp8, p14);
if (rc)
return rc;
rc = smbhash(p16 + 8, sp8, p14 + 7);
return rc;
}
static int
E_P24(unsigned char *p21, const unsigned char *c8, unsigned char *p24)
{
int rc;
rc = smbhash(p24, c8, p21);
if (rc)
return rc;
rc = smbhash(p24 + 8, c8, p21 + 7);
if (rc)
return rc;
rc = smbhash(p24 + 16, c8, p21 + 14);
return rc;
}
/* produce a md4 message digest from data of length n bytes */
int
mdfour(unsigned char *md4_hash, unsigned char *link_str, int link_len)
{
int rc;
struct crypto_shash *md4 = NULL;
struct sdesc *sdescmd4 = NULL;
rc = cifs_alloc_hash("md4", &md4, &sdescmd4);
if (rc)
goto mdfour_err;
rc = crypto_shash_init(&sdescmd4->shash);
if (rc) {
cifs_dbg(VFS, "%s: Could not init md4 shash\n", __func__);
goto mdfour_err;
}
rc = crypto_shash_update(&sdescmd4->shash, link_str, link_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with link_str\n", __func__);
goto mdfour_err;
}
rc = crypto_shash_final(&sdescmd4->shash, md4_hash);
if (rc)
cifs_dbg(VFS, "%s: Could not generate md4 hash\n", __func__);
mdfour_err:
cifs_free_hash(&md4, &sdescmd4);
return rc;
}
/*
This implements the X/Open SMB password encryption
It takes a password, a 8 byte "crypt key" and puts 24 bytes of
encrypted password into p24 */
/* Note that password must be uppercased and null terminated */
int
SMBencrypt(unsigned char *passwd, const unsigned char *c8, unsigned char *p24)
{
int rc;
unsigned char p14[14], p16[16], p21[21];
memset(p14, '\0', 14);
memset(p16, '\0', 16);
memset(p21, '\0', 21);
memcpy(p14, passwd, 14);
rc = E_P16(p14, p16);
if (rc)
return rc;
memcpy(p21, p16, 16);
rc = E_P24(p21, c8, p24);
return rc;
}
/*
* Creates the MD4 Hash of the users password in NT UNICODE.
*/
int
E_md4hash(const unsigned char *passwd, unsigned char *p16,
const struct nls_table *codepage)
{
int rc;
int len;
__le16 wpwd[129];
/* Password cannot be longer than 128 characters */
if (passwd) /* Password must be converted to NT unicode */
len = cifs_strtoUTF16(wpwd, passwd, 128, codepage);
else {
len = 0;
*wpwd = 0; /* Ensure string is null terminated */
}
rc = mdfour(p16, (unsigned char *) wpwd, len * sizeof(__le16));
memzero_explicit(wpwd, sizeof(wpwd));
return rc;
}
/* Does the NT MD4 hash then des encryption. */
int
SMBNTencrypt(unsigned char *passwd, unsigned char *c8, unsigned char *p24,
const struct nls_table *codepage)
{
int rc;
unsigned char p16[16], p21[21];
memset(p16, '\0', 16);
memset(p21, '\0', 21);
rc = E_md4hash(passwd, p16, codepage);
if (rc) {
cifs_dbg(FYI, "%s Can't generate NT hash, error: %d\n",
__func__, rc);
return rc;
}
memcpy(p21, p16, 16);
rc = E_P24(p21, c8, p24);
return rc;
}