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 #include "gss_krb5_internal.h"
69
70 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
71 # define RPCDBG_FACILITY RPCDBG_AUTH
72 #endif
73
74 #if defined(CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED)
75
76 static void *
setup_token(struct krb5_ctx * ctx,struct xdr_netobj * token)77 setup_token(struct krb5_ctx *ctx, struct xdr_netobj *token)
78 {
79 u16 *ptr;
80 void *krb5_hdr;
81 int body_size = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
82
83 token->len = g_token_size(&ctx->mech_used, body_size);
84
85 ptr = (u16 *)token->data;
86 g_make_token_header(&ctx->mech_used, body_size, (unsigned char **)&ptr);
87
88 /* ptr now at start of header described in rfc 1964, section 1.2.1: */
89 krb5_hdr = ptr;
90 *ptr++ = KG_TOK_MIC_MSG;
91 /*
92 * signalg is stored as if it were converted from LE to host endian, even
93 * though it's an opaque pair of bytes according to the RFC.
94 */
95 *ptr++ = (__force u16)cpu_to_le16(ctx->gk5e->signalg);
96 *ptr++ = SEAL_ALG_NONE;
97 *ptr = 0xffff;
98
99 return krb5_hdr;
100 }
101
102 u32
gss_krb5_get_mic_v1(struct krb5_ctx * ctx,struct xdr_buf * text,struct xdr_netobj * token)103 gss_krb5_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text,
104 struct xdr_netobj *token)
105 {
106 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
107 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
108 .data = cksumdata};
109 void *ptr;
110 time64_t now;
111 u32 seq_send;
112 u8 *cksumkey;
113
114 dprintk("RPC: %s\n", __func__);
115 BUG_ON(ctx == NULL);
116
117 now = ktime_get_real_seconds();
118
119 ptr = setup_token(ctx, token);
120
121 if (ctx->gk5e->keyed_cksum)
122 cksumkey = ctx->cksum;
123 else
124 cksumkey = NULL;
125
126 if (make_checksum(ctx, ptr, 8, text, 0, cksumkey,
127 KG_USAGE_SIGN, &md5cksum))
128 return GSS_S_FAILURE;
129
130 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
131
132 seq_send = atomic_fetch_inc(&ctx->seq_send);
133
134 if (krb5_make_seq_num(ctx, ctx->seq, ctx->initiate ? 0 : 0xff,
135 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8))
136 return GSS_S_FAILURE;
137
138 return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
139 }
140
141 #endif
142
143 static void *
setup_token_v2(struct krb5_ctx * ctx,struct xdr_netobj * token)144 setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token)
145 {
146 u16 *ptr;
147 void *krb5_hdr;
148 u8 *p, flags = 0x00;
149
150 if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
151 flags |= 0x01;
152 if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY)
153 flags |= 0x04;
154
155 /* Per rfc 4121, sec 4.2.6.1, there is no header,
156 * just start the token.
157 */
158 krb5_hdr = (u16 *)token->data;
159 ptr = krb5_hdr;
160
161 *ptr++ = KG2_TOK_MIC;
162 p = (u8 *)ptr;
163 *p++ = flags;
164 *p++ = 0xff;
165 ptr = (u16 *)p;
166 *ptr++ = 0xffff;
167 *ptr = 0xffff;
168
169 token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength;
170 return krb5_hdr;
171 }
172
173 u32
gss_krb5_get_mic_v2(struct krb5_ctx * ctx,struct xdr_buf * text,struct xdr_netobj * token)174 gss_krb5_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text,
175 struct xdr_netobj *token)
176 {
177 struct crypto_ahash *tfm = ctx->initiate ?
178 ctx->initiator_sign : ctx->acceptor_sign;
179 struct xdr_netobj cksumobj = {
180 .len = ctx->gk5e->cksumlength,
181 };
182 __be64 seq_send_be64;
183 void *krb5_hdr;
184 time64_t now;
185
186 dprintk("RPC: %s\n", __func__);
187
188 krb5_hdr = setup_token_v2(ctx, token);
189
190 /* Set up the sequence number. Now 64-bits in clear
191 * text and w/o direction indicator */
192 seq_send_be64 = cpu_to_be64(atomic64_fetch_inc(&ctx->seq_send64));
193 memcpy(krb5_hdr + 8, (char *) &seq_send_be64, 8);
194
195 cksumobj.data = krb5_hdr + GSS_KRB5_TOK_HDR_LEN;
196 if (gss_krb5_checksum(tfm, krb5_hdr, GSS_KRB5_TOK_HDR_LEN,
197 text, 0, &cksumobj))
198 return GSS_S_FAILURE;
199
200 now = ktime_get_real_seconds();
201 return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
202 }
203