linux-stable/fs/cifs/smbencrypt.c
Steve French 2baa268253 Remap reserved posix characters by default (part 3/3)
This is a bigger patch, but its size is mostly due to
a single change for how we check for remapping illegal characters
in file names - a lot of repeated, small changes to
the way callers request converting file names.

The final patch in the series does the following:

1) changes default behavior for cifs to be more intuitive.
Currently we do not map by default to seven reserved characters,
ie those valid in POSIX but not in NTFS/CIFS/SMB3/Windows,
unless a mount option (mapchars) is specified.  Change this
to by default always map and map using the SFM maping
(like the Mac uses) unless the server negotiates the CIFS Unix
Extensions (like Samba does when mounting with the cifs protocol)
when the remapping of the characters is unnecessary.  This should
help SMB3 mounts in particular since Samba will likely be
able to implement this mapping with its new "vfs_fruit" module
as it will be doing for the Mac.
2) if the user specifies the existing "mapchars" mount option then
use the "SFU" (Microsoft Services for Unix, SUA) style mapping of
the seven characters instead.
3) if the user specifies "nomapposix" then disable SFM/MAC style mapping
(so no character remapping would be used unless the user specifies
"mapchars" on mount as well, as above).
4) change all the places in the code that check for the superblock
flag on the mount which is set by mapchars and passed in on all
path based operation and change it to use a small function call
instead to set the mapping type properly (and check for the
mapping type in the cifs unicode functions)

Signed-off-by: Steve French <smfrench@gmail.com>
2014-10-16 15:20:20 -05:00

249 lines
6 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/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)
{
int rc;
unsigned char key2[8];
struct crypto_blkcipher *tfm_des;
struct scatterlist sgin, sgout;
struct blkcipher_desc desc;
str_to_key(key, key2);
tfm_des = crypto_alloc_blkcipher("ecb(des)", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm_des)) {
rc = PTR_ERR(tfm_des);
cifs_dbg(VFS, "could not allocate des crypto API\n");
goto smbhash_err;
}
desc.tfm = tfm_des;
crypto_blkcipher_setkey(tfm_des, key2, 8);
sg_init_one(&sgin, in, 8);
sg_init_one(&sgout, out, 8);
rc = crypto_blkcipher_encrypt(&desc, &sgout, &sgin, 8);
if (rc)
cifs_dbg(VFS, "could not encrypt crypt key rc: %d\n", rc);
crypto_free_blkcipher(tfm_des);
smbhash_err:
return rc;
}
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));
memset(wpwd, 0, 129 * sizeof(__le16));
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;
}