xref: /openbmc/linux/net/sunrpc/auth_gss/gss_krb5_seal.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b)
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 <linux/crypto.h>
67 
68 #ifdef RPC_DEBUG
69 # define RPCDBG_FACILITY        RPCDBG_AUTH
70 #endif
71 
72 DEFINE_SPINLOCK(krb5_seq_lock);
73 
74 u32
75 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text,
76 		struct xdr_netobj *token)
77 {
78 	struct krb5_ctx		*ctx = gss_ctx->internal_ctx_id;
79 	char			cksumdata[16];
80 	struct xdr_netobj	md5cksum = {.len = 0, .data = cksumdata};
81 	unsigned char		*ptr, *msg_start;
82 	s32			now;
83 	u32			seq_send;
84 
85 	dprintk("RPC:       gss_krb5_seal\n");
86 	BUG_ON(ctx == NULL);
87 
88 	now = get_seconds();
89 
90 	token->len = g_token_size(&ctx->mech_used, GSS_KRB5_TOK_HDR_LEN + 8);
91 
92 	ptr = token->data;
93 	g_make_token_header(&ctx->mech_used, GSS_KRB5_TOK_HDR_LEN + 8, &ptr);
94 
95 	/* ptr now at header described in rfc 1964, section 1.2.1: */
96 	ptr[0] = (unsigned char) ((KG_TOK_MIC_MSG >> 8) & 0xff);
97 	ptr[1] = (unsigned char) (KG_TOK_MIC_MSG & 0xff);
98 
99 	msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + 8;
100 
101 	*(__be16 *)(ptr + 2) = htons(SGN_ALG_DES_MAC_MD5);
102 	memset(ptr + 4, 0xff, 4);
103 
104 	if (make_checksum("md5", ptr, 8, text, 0, &md5cksum))
105 		return GSS_S_FAILURE;
106 
107 	if (krb5_encrypt(ctx->seq, NULL, md5cksum.data,
108 			  md5cksum.data, md5cksum.len))
109 		return GSS_S_FAILURE;
110 
111 	memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data + md5cksum.len - 8, 8);
112 
113 	spin_lock(&krb5_seq_lock);
114 	seq_send = ctx->seq_send++;
115 	spin_unlock(&krb5_seq_lock);
116 
117 	if (krb5_make_seq_num(ctx->seq, ctx->initiate ? 0 : 0xff,
118 			      seq_send, ptr + GSS_KRB5_TOK_HDR_LEN,
119 			      ptr + 8))
120 		return GSS_S_FAILURE;
121 
122 	return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
123 }
124