1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
|
/*
* COPYRIGHT (c) 2008
* The Regents of the University of Michigan
* ALL RIGHTS RESERVED
*
* Permission is granted to use, copy, create derivative works
* and redistribute this software and such derivative works
* for any purpose, so long as the name of The University of
* Michigan is not used in any advertising or publicity
* pertaining to the use of distribution of this software
* without specific, written prior authorization. If the
* above copyright notice or any other identification of the
* University of Michigan is included in any copy of any
* portion of this software, then the disclaimer below must
* also be included.
*
* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
* FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
* PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
* MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
* WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
* REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
* FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
* CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
* OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGES.
*/
/*
* Copyright (C) 1998 by the FundsXpress, INC.
*
* All rights reserved.
*
* Export of this software from the United States of America may require
* a specific license from the United States Government. It is the
* responsibility of any person or organization contemplating export to
* obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of FundsXpress. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. FundsXpress makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <linux/err.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.h>
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
/*
* This is the n-fold function as described in rfc3961, sec 5.1
* Taken from MIT Kerberos and modified.
*/
static void krb5_nfold(u32 inbits, const u8 *in,
u32 outbits, u8 *out)
{
int a, b, c, lcm;
int byte, i, msbit;
/* the code below is more readable if I make these bytes
instead of bits */
inbits >>= 3;
outbits >>= 3;
/* first compute lcm(n,k) */
a = outbits;
b = inbits;
while (b != 0) {
c = b;
b = a%b;
a = c;
}
lcm = outbits*inbits/a;
/* now do the real work */
memset(out, 0, outbits);
byte = 0;
/* this will end up cycling through k lcm(k,n)/k times, which
is correct */
for (i = lcm-1; i >= 0; i--) {
/* compute the msbit in k which gets added into this byte */
msbit = (
/* first, start with the msbit in the first,
* unrotated byte */
((inbits << 3) - 1)
/* then, for each byte, shift to the right
* for each repetition */
+ (((inbits << 3) + 13) * (i/inbits))
/* last, pick out the correct byte within
* that shifted repetition */
+ ((inbits - (i % inbits)) << 3)
) % (inbits << 3);
/* pull out the byte value itself */
byte += (((in[((inbits - 1) - (msbit >> 3)) % inbits] << 8)|
(in[((inbits) - (msbit >> 3)) % inbits]))
>> ((msbit & 7) + 1)) & 0xff;
/* do the addition */
byte += out[i % outbits];
out[i % outbits] = byte & 0xff;
/* keep around the carry bit, if any */
byte >>= 8;
}
/* if there's a carry bit left over, add it back in */
if (byte) {
for (i = outbits - 1; i >= 0; i--) {
/* do the addition */
byte += out[i];
out[i] = byte & 0xff;
/* keep around the carry bit, if any */
byte >>= 8;
}
}
}
/*
* This is the DK (derive_key) function as described in rfc3961, sec 5.1
* Taken from MIT Kerberos and modified.
*/
u32 krb5_derive_key(struct gss_krb5_enctype *gk5e,
const struct xdr_netobj *inkey,
struct xdr_netobj *outkey,
const struct xdr_netobj *in_constant)
{
size_t blocksize, keybytes, keylength, n;
unsigned char *inblockdata, *outblockdata, *rawkey;
struct xdr_netobj inblock, outblock;
struct crypto_blkcipher *cipher;
u32 ret = EINVAL;
blocksize = gk5e->blocksize;
keybytes = gk5e->keybytes;
keylength = gk5e->keylength;
if ((inkey->len != keylength) || (outkey->len != keylength))
goto err_return;
cipher = crypto_alloc_blkcipher(gk5e->encrypt_name, 0,
CRYPTO_ALG_ASYNC);
if (IS_ERR(cipher))
goto err_return;
if (crypto_blkcipher_setkey(cipher, inkey->data, inkey->len))
goto err_return;
/* allocate and set up buffers */
ret = ENOMEM;
inblockdata = kmalloc(blocksize, GFP_KERNEL);
if (inblockdata == NULL)
goto err_free_cipher;
outblockdata = kmalloc(blocksize, GFP_KERNEL);
if (outblockdata == NULL)
goto err_free_in;
rawkey = kmalloc(keybytes, GFP_KERNEL);
if (rawkey == NULL)
goto err_free_out;
inblock.data = (char *) inblockdata;
inblock.len = blocksize;
outblock.data = (char *) outblockdata;
outblock.len = blocksize;
/* initialize the input block */
if (in_constant->len == inblock.len) {
memcpy(inblock.data, in_constant->data, inblock.len);
} else {
krb5_nfold(in_constant->len * 8, in_constant->data,
inblock.len * 8, inblock.data);
}
/* loop encrypting the blocks until enough key bytes are generated */
n = 0;
while (n < keybytes) {
(*(gk5e->encrypt))(cipher, NULL, inblock.data,
outblock.data, inblock.len);
if ((keybytes - n) <= outblock.len) {
memcpy(rawkey + n, outblock.data, (keybytes - n));
break;
}
memcpy(rawkey + n, outblock.data, outblock.len);
memcpy(inblock.data, outblock.data, outblock.len);
n += outblock.len;
}
/* postprocess the key */
inblock.data = (char *) rawkey;
inblock.len = keybytes;
BUG_ON(gk5e->mk_key == NULL);
ret = (*(gk5e->mk_key))(gk5e, &inblock, outkey);
if (ret) {
dprintk("%s: got %d from mk_key function for '%s'\n",
__func__, ret, gk5e->encrypt_name);
goto err_free_raw;
}
/* clean memory, free resources and exit */
ret = 0;
err_free_raw:
memset(rawkey, 0, keybytes);
kfree(rawkey);
err_free_out:
memset(outblockdata, 0, blocksize);
kfree(outblockdata);
err_free_in:
memset(inblockdata, 0, blocksize);
kfree(inblockdata);
err_free_cipher:
crypto_free_blkcipher(cipher);
err_return:
return ret;
}
|
