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gss_krb5_seqnum.c
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1 /*
2  * linux/net/sunrpc/gss_krb5_seqnum.c
3  *
4  * Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/util_seqnum.c
5  *
6  * Copyright (c) 2000 The Regents of the University of Michigan.
7  * All rights reserved.
8  *
9  * Andy Adamson <[email protected]>
10  */
11 
12 /*
13  * Copyright 1993 by OpenVision Technologies, Inc.
14  *
15  * Permission to use, copy, modify, distribute, and sell this software
16  * and its documentation for any purpose is hereby granted without fee,
17  * provided that the above copyright notice appears in all copies and
18  * that both that copyright notice and this permission notice appear in
19  * supporting documentation, and that the name of OpenVision not be used
20  * in advertising or publicity pertaining to distribution of the software
21  * without specific, written prior permission. OpenVision makes no
22  * representations about the suitability of this software for any
23  * purpose. It is provided "as is" without express or implied warranty.
24  *
25  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
26  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
27  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
28  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
29  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
30  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
31  * PERFORMANCE OF THIS SOFTWARE.
32  */
33 
34 #include <linux/types.h>
35 #include <linux/sunrpc/gss_krb5.h>
36 #include <linux/crypto.h>
37 
38 #ifdef RPC_DEBUG
39 # define RPCDBG_FACILITY RPCDBG_AUTH
40 #endif
41 
42 static s32
43 krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
44  unsigned char *cksum, unsigned char *buf)
45 {
46  struct crypto_blkcipher *cipher;
47  unsigned char plain[8];
48  s32 code;
49 
50  dprintk("RPC: %s:\n", __func__);
51  cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
53  if (IS_ERR(cipher))
54  return PTR_ERR(cipher);
55 
56  plain[0] = (unsigned char) ((seqnum >> 24) & 0xff);
57  plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
58  plain[2] = (unsigned char) ((seqnum >> 8) & 0xff);
59  plain[3] = (unsigned char) ((seqnum >> 0) & 0xff);
60  plain[4] = direction;
61  plain[5] = direction;
62  plain[6] = direction;
63  plain[7] = direction;
64 
65  code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
66  if (code)
67  goto out;
68 
69  code = krb5_encrypt(cipher, cksum, plain, buf, 8);
70 out:
71  crypto_free_blkcipher(cipher);
72  return code;
73 }
74 s32
76  struct crypto_blkcipher *key,
77  int direction,
78  u32 seqnum,
79  unsigned char *cksum, unsigned char *buf)
80 {
81  unsigned char plain[8];
82 
83  if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
84  return krb5_make_rc4_seq_num(kctx, direction, seqnum,
85  cksum, buf);
86 
87  plain[0] = (unsigned char) (seqnum & 0xff);
88  plain[1] = (unsigned char) ((seqnum >> 8) & 0xff);
89  plain[2] = (unsigned char) ((seqnum >> 16) & 0xff);
90  plain[3] = (unsigned char) ((seqnum >> 24) & 0xff);
91 
92  plain[4] = direction;
93  plain[5] = direction;
94  plain[6] = direction;
95  plain[7] = direction;
96 
97  return krb5_encrypt(key, cksum, plain, buf, 8);
98 }
99 
100 static s32
101 krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
102  unsigned char *buf, int *direction, s32 *seqnum)
103 {
104  struct crypto_blkcipher *cipher;
105  unsigned char plain[8];
106  s32 code;
107 
108  dprintk("RPC: %s:\n", __func__);
109  cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
111  if (IS_ERR(cipher))
112  return PTR_ERR(cipher);
113 
114  code = krb5_rc4_setup_seq_key(kctx, cipher, cksum);
115  if (code)
116  goto out;
117 
118  code = krb5_decrypt(cipher, cksum, buf, plain, 8);
119  if (code)
120  goto out;
121 
122  if ((plain[4] != plain[5]) || (plain[4] != plain[6])
123  || (plain[4] != plain[7])) {
124  code = (s32)KG_BAD_SEQ;
125  goto out;
126  }
127 
128  *direction = plain[4];
129 
130  *seqnum = ((plain[0] << 24) | (plain[1] << 16) |
131  (plain[2] << 8) | (plain[3]));
132 out:
133  crypto_free_blkcipher(cipher);
134  return code;
135 }
136 
137 s32
139  unsigned char *cksum,
140  unsigned char *buf,
141  int *direction, u32 *seqnum)
142 {
143  s32 code;
144  unsigned char plain[8];
145  struct crypto_blkcipher *key = kctx->seq;
146 
147  dprintk("RPC: krb5_get_seq_num:\n");
148 
149  if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
150  return krb5_get_rc4_seq_num(kctx, cksum, buf,
151  direction, seqnum);
152 
153  if ((code = krb5_decrypt(key, cksum, buf, plain, 8)))
154  return code;
155 
156  if ((plain[4] != plain[5]) || (plain[4] != plain[6]) ||
157  (plain[4] != plain[7]))
158  return (s32)KG_BAD_SEQ;
159 
160  *direction = plain[4];
161 
162  *seqnum = ((plain[0]) |
163  (plain[1] << 8) | (plain[2] << 16) | (plain[3] << 24));
164 
165  return 0;
166 }