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) 2000-2008 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/jiffies.h>
63 #include <linux/sunrpc/gss_krb5.h>
64 #include <linux/random.h>
65 #include <linux/crypto.h>
66 #include <linux/atomic.h>
67
68 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
69 # define RPCDBG_FACILITY RPCDBG_AUTH
70 #endif
71
72 static void *
73 setup_token(struct krb5_ctx *ctx, struct xdr_netobj *token)
74 {
75 u16 *ptr;
76 void *krb5_hdr;
77 int body_size = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
78
79 token->len = g_token_size(&ctx->mech_used, body_size);
80
81 ptr = (u16 *)token->data;
82 g_make_token_header(&ctx->mech_used, body_size, (unsigned char **)&ptr);
83
84 /* ptr now at start of header described in rfc 1964, section 1.2.1: */
85 krb5_hdr = ptr;
86 *ptr++ = KG_TOK_MIC_MSG;
87 /*
88 * signalg is stored as if it were converted from LE to host endian, even
89 * though it's an opaque pair of bytes according to the RFC.
90 */
91 *ptr++ = (__force u16)cpu_to_le16(ctx->gk5e->signalg);
92 *ptr++ = SEAL_ALG_NONE;
93 *ptr = 0xffff;
94
95 return krb5_hdr;
96 }
97
98 static void *
99 setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token)
100 {
101 u16 *ptr;
102 void *krb5_hdr;
103 u8 *p, flags = 0x00;
104
105 if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
106 flags |= 0x01;
107 if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY)
108 flags |= 0x04;
109
110 /* Per rfc 4121, sec 4.2.6.1, there is no header,
111 * just start the token */
112 krb5_hdr = ptr = (u16 *)token->data;
113
114 *ptr++ = KG2_TOK_MIC;
115 p = (u8 *)ptr;
116 *p++ = flags;
117 *p++ = 0xff;
118 ptr = (u16 *)p;
119 *ptr++ = 0xffff;
120 *ptr = 0xffff;
121
122 token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
123 return krb5_hdr;
124 }
125
126 static u32
127 gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text,
128 struct xdr_netobj *token)
129 {
130 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
131 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
132 .data = cksumdata};
133 void *ptr;
134 s32 now;
135 u32 seq_send;
136 u8 *cksumkey;
137
138 dprintk("RPC: %s\n", __func__);
139 BUG_ON(ctx == NULL);
140
141 now = get_seconds();
142
143 ptr = setup_token(ctx, token);
144
145 if (ctx->gk5e->keyed_cksum)
146 cksumkey = ctx->cksum;
147 else
148 cksumkey = NULL;
149
150 if (make_checksum(ctx, ptr, 8, text, 0, cksumkey,
151 KG_USAGE_SIGN, &md5cksum))
152 return GSS_S_FAILURE;
153
154 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
155
156 seq_send = atomic_fetch_inc(&ctx->seq_send);
157
158 if (krb5_make_seq_num(ctx, ctx->seq, ctx->initiate ? 0 : 0xff,
159 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))
160 return GSS_S_FAILURE;
161
162 return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
163 }
164
165 static u32
166 gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
167 struct xdr_netobj *token)
168 {
169 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
170 struct xdr_netobj cksumobj = { .len = sizeof(cksumdata),
171 .data = cksumdata};
172 void *krb5_hdr;
173 s32 now;
174 u8 *cksumkey;
175 unsigned int cksum_usage;
176 __be64 seq_send_be64;
177
178 dprintk("RPC: %s\n", __func__);
179
180 krb5_hdr = setup_token_v2(ctx, token);
181
182 /* Set up the sequence number. Now 64-bits in clear
183 * text and w/o direction indicator */
184 seq_send_be64 = cpu_to_be64(atomic64_fetch_inc(&ctx->seq_send64));
185 memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
186
187 if (ctx->initiate) {
188 cksumkey = ctx->initiator_sign;
189 cksum_usage = KG_USAGE_INITIATOR_SIGN;
190 } else {
191 cksumkey = ctx->acceptor_sign;
192 cksum_usage = KG_USAGE_ACCEPTOR_SIGN;
193 }
194
195 if (make_checksum_v2(ctx, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
196 text, 0, cksumkey, cksum_usage, &cksumobj))
197 return GSS_S_FAILURE;
198
199 memcpy(krb5_hdr + GSS_KRB5_TOK_HDR_LEN, cksumobj.data, cksumobj.len);
200
201 now = get_seconds();
202
203 return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
204 }
205
206 u32
207 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
208 struct xdr_netobj *token)
209 {
210 struct krb5_ctx *ctx = gss_ctx->internal_ctx_id;
211
212 switch (ctx->enctype) {
213 default:
214 BUG();
215 case ENCTYPE_DES_CBC_RAW:
216 case ENCTYPE_DES3_CBC_RAW:
217 case ENCTYPE_ARCFOUR_HMAC:
218 return gss_get_mic_v1(ctx, text, token);
219 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
220 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
221 return gss_get_mic_v2(ctx, text, token);
222 }
223 }