1 /*
2  *  linux/net/sunrpc/gss_krb5_seal.c
3  *
4  *  Adapted from MIT Kerberos 5-1.2.1 lib/gssapi/krb5/k5seal.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  *  J. Bruce Fields	<bfields@umich.edu>
11  */
12 
13 /*
14  * Copyright 1993 by OpenVision Technologies, Inc.
15  *
16  * Permission to use, copy, modify, distribute, and sell this software
17  * and its documentation for any purpose is hereby granted without fee,
18  * provided that the above copyright notice appears in all copies and
19  * that both that copyright notice and this permission notice appear in
20  * supporting documentation, and that the name of OpenVision not be used
21  * in advertising or publicity pertaining to distribution of the software
22  * without specific, written prior permission. OpenVision makes no
23  * representations about the suitability of this software for any
24  * purpose.  It is provided "as is" without express or implied warranty.
25  *
26  * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
27  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
28  * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
29  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
30  * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
31  * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
32  * PERFORMANCE OF THIS SOFTWARE.
33  */
34 
35 /*
36  * Copyright (C) 1998 by the FundsXpress, INC.
37  *
38  * All rights reserved.
39  *
40  * Export of this software from the United States of America may require
41  * a specific license from the United States Government.  It is the
42  * responsibility of any person or organization contemplating export to
43  * obtain such a license before exporting.
44  *
45  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
46  * distribute this software and its documentation for any purpose and
47  * without fee is hereby granted, provided that the above copyright
48  * notice appear in all copies and that both that copyright notice and
49  * this permission notice appear in supporting documentation, and that
50  * the name of FundsXpress. not be used in advertising or publicity pertaining
51  * to distribution of the software without specific, written prior
52  * permission.  FundsXpress makes no representations about the suitability of
53  * this software for any purpose.  It is provided "as is" without express
54  * or implied warranty.
55  *
56  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
57  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
58  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
59  */
60 
61 #include <linux/types.h>
62 #include <linux/slab.h>
63 #include <linux/jiffies.h>
64 #include <linux/sunrpc/gss_krb5.h>
65 #include <linux/random.h>
66 #include <asm/scatterlist.h>
67 #include <linux/crypto.h>
68 
69 #ifdef RPC_DEBUG
70 # define RPCDBG_FACILITY        RPCDBG_AUTH
71 #endif
72 
73 u32
74 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
75 		struct xdr_netobj *token)
76 {
77 	struct krb5_ctx		*ctx = gss_ctx->internal_ctx_id;
78 	s32			checksum_type;
79 	struct xdr_netobj	md5cksum = {.len = 0, .data = NULL};
80 	unsigned char		*ptr, *krb5_hdr, *msg_start;
81 	s32			now;
82 
83 	dprintk("RPC:     gss_krb5_seal\n");
84 
85 	now = get_seconds();
86 
87 	switch (ctx->signalg) {
88 		case SGN_ALG_DES_MAC_MD5:
89 			checksum_type = CKSUMTYPE_RSA_MD5;
90 			break;
91 		default:
92 			dprintk("RPC:      gss_krb5_seal: ctx->signalg %d not"
93 				" supported\n", ctx->signalg);
94 			goto out_err;
95 	}
96 	if (ctx->sealalg != SEAL_ALG_NONE && ctx->sealalg != SEAL_ALG_DES) {
97 		dprintk("RPC:      gss_krb5_seal: ctx->sealalg %d not supported\n",
98 			ctx->sealalg);
99 		goto out_err;
100 	}
101 
102 	token->len = g_token_size(&ctx->mech_used, 22);
103 
104 	ptr = token->data;
105 	g_make_token_header(&ctx->mech_used, 22, &ptr);
106 
107 	*ptr++ = (unsigned char) ((KG_TOK_MIC_MSG>>8)&0xff);
108 	*ptr++ = (unsigned char) (KG_TOK_MIC_MSG&0xff);
109 
110 	/* ptr now at byte 2 of header described in rfc 1964, section 1.2.1: */
111 	krb5_hdr = ptr - 2;
112 	msg_start = krb5_hdr + 24;
113 
114 	*(u16 *)(krb5_hdr + 2) = htons(ctx->signalg);
115 	memset(krb5_hdr + 4, 0xff, 4);
116 
117 	if (make_checksum(checksum_type, krb5_hdr, 8, text, 0, &md5cksum))
118 			goto out_err;
119 
120 	switch (ctx->signalg) {
121 	case SGN_ALG_DES_MAC_MD5:
122 		if (krb5_encrypt(ctx->seq, NULL, md5cksum.data,
123 				  md5cksum.data, md5cksum.len))
124 			goto out_err;
125 		memcpy(krb5_hdr + 16,
126 		       md5cksum.data + md5cksum.len - KRB5_CKSUM_LENGTH,
127 		       KRB5_CKSUM_LENGTH);
128 
129 		dprintk("RPC:      make_seal_token: cksum data: \n");
130 		print_hexl((u32 *) (krb5_hdr + 16), KRB5_CKSUM_LENGTH, 0);
131 		break;
132 	default:
133 		BUG();
134 	}
135 
136 	kfree(md5cksum.data);
137 
138 	if ((krb5_make_seq_num(ctx->seq, ctx->initiate ? 0 : 0xff,
139 			       ctx->seq_send, krb5_hdr + 16, krb5_hdr + 8)))
140 		goto out_err;
141 
142 	ctx->seq_send++;
143 
144 	return ((ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
145 out_err:
146 	kfree(md5cksum.data);
147 	return GSS_S_FAILURE;
148 }
149