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   <andros@umich.edu>
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
39# define RPCDBG_FACILITY        RPCDBG_AUTH
40#endif
41
42static s32
43krb5_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,
52					CRYPTO_ALG_ASYNC);
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);
70out:
71	crypto_free_blkcipher(cipher);
72	return code;
73}
74s32
75krb5_make_seq_num(struct krb5_ctx *kctx,
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
100static s32
101krb5_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,
110					CRYPTO_ALG_ASYNC);
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]));
132out:
133	crypto_free_blkcipher(cipher);
134	return code;
135}
136
137s32
138krb5_get_seq_num(struct krb5_ctx *kctx,
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}
167