linux/fs/cifs/smbencrypt.c
Andy Lutomirski 06deeec77a cifs: Fix smbencrypt() to stop pointing a scatterlist at the stack
smbencrypt() points a scatterlist to the stack, which is breaks if
CONFIG_VMAP_STACK=y.

Fix it by switching to crypto_cipher_encrypt_one().  The new code
should be considerably faster as an added benefit.

This code is nearly identical to some code that Eric Biggers
suggested.

Cc: stable@vger.kernel.org # 4.9 only
Reported-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
2016-12-14 01:44:16 -06:00

238 lines
5.7 KiB
C

/*
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
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.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/crypto.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/random.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 crypto_cipher *tfm_des;
str_to_key(key, key2);
tfm_des = crypto_alloc_cipher("des", 0, 0);
if (IS_ERR(tfm_des)) {
cifs_dbg(VFS, "could not allocate des crypto API\n");
return PTR_ERR(tfm_des);
}
crypto_cipher_setkey(tfm_des, key2, 8);
crypto_cipher_encrypt_one(tfm_des, out, in);
crypto_free_cipher(tfm_des);
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;
unsigned int size;
struct crypto_shash *md4;
struct sdesc *sdescmd4;
md4 = crypto_alloc_shash("md4", 0, 0);
if (IS_ERR(md4)) {
rc = PTR_ERR(md4);
cifs_dbg(VFS, "%s: Crypto md4 allocation error %d\n",
__func__, rc);
return rc;
}
size = sizeof(struct shash_desc) + crypto_shash_descsize(md4);
sdescmd4 = kmalloc(size, GFP_KERNEL);
if (!sdescmd4) {
rc = -ENOMEM;
goto mdfour_err;
}
sdescmd4->shash.tfm = md4;
sdescmd4->shash.flags = 0x0;
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:
crypto_free_shash(md4);
kfree(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;
}