1 /*-
2 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
3 * Authors: Doug Rabson <dfr@rabson.org>
4 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30
31 #include <sys/param.h>
32 #include <sys/lock.h>
33 #include <sys/malloc.h>
34 #include <sys/md5.h>
35 #include <sys/kobj.h>
36 #include <sys/mbuf.h>
37 #include <crypto/rc4/rc4.h>
38
39 #include <kgssapi/gssapi.h>
40 #include <kgssapi/gssapi_impl.h>
41
42 #include "kcrypto.h"
43
44 static void
arcfour_init(struct krb5_key_state * ks)45 arcfour_init(struct krb5_key_state *ks)
46 {
47
48 ks->ks_priv = NULL;
49 }
50
51 static void
arcfour_destroy(struct krb5_key_state * ks)52 arcfour_destroy(struct krb5_key_state *ks)
53 {
54
55 }
56
57 static void
arcfour_set_key(struct krb5_key_state * ks,const void * in)58 arcfour_set_key(struct krb5_key_state *ks, const void *in)
59 {
60 void *kp = ks->ks_key;
61
62 if (kp != in)
63 bcopy(in, kp, 16);
64 }
65
66 static void
arcfour_random_to_key(struct krb5_key_state * ks,const void * in)67 arcfour_random_to_key(struct krb5_key_state *ks, const void *in)
68 {
69
70 arcfour_set_key(ks, in);
71 }
72
73 static void
arcfour_hmac(uint8_t * key,uint8_t * data,size_t datalen,uint8_t * result)74 arcfour_hmac(uint8_t *key, uint8_t *data, size_t datalen,
75 uint8_t *result)
76 {
77 uint8_t buf[64];
78 MD5_CTX md5;
79 int i;
80
81 for (i = 0; i < 16; i++)
82 buf[i] = key[i] ^ 0x36;
83 for (; i < 64; i++)
84 buf[i] = 0x36;
85
86 MD5Init(&md5);
87 MD5Update(&md5, buf, 64);
88 MD5Update(&md5, data, datalen);
89 MD5Final(result, &md5);
90
91 for (i = 0; i < 16; i++)
92 buf[i] = key[i] ^ 0x5c;
93 for (; i < 64; i++)
94 buf[i] = 0x5c;
95
96 MD5Init(&md5);
97 MD5Update(&md5, buf, 64);
98 MD5Update(&md5, result, 16);
99 MD5Final(result, &md5);
100 }
101
102 static void
arcfour_derive_key(const struct krb5_key_state * ks,uint32_t usage,uint8_t * newkey)103 arcfour_derive_key(const struct krb5_key_state *ks, uint32_t usage,
104 uint8_t *newkey)
105 {
106 uint8_t t[4];
107
108 t[0] = (usage >> 24);
109 t[1] = (usage >> 16);
110 t[2] = (usage >> 8);
111 t[3] = (usage >> 0);
112 if (ks->ks_class->ec_type == ETYPE_ARCFOUR_HMAC_MD5_56) {
113 uint8_t L40[14] = "fortybits";
114 bcopy(t, L40 + 10, 4);
115 arcfour_hmac(ks->ks_key, L40, 14, newkey);
116 memset(newkey + 7, 0xab, 9);
117 } else {
118 arcfour_hmac(ks->ks_key, t, 4, newkey);
119 }
120 }
121
122 static int
rc4_crypt_int(void * rs,void * buf,u_int len)123 rc4_crypt_int(void *rs, void *buf, u_int len)
124 {
125
126 rc4_crypt(rs, buf, buf, len);
127 return (0);
128 }
129
130 static void
arcfour_encrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)131 arcfour_encrypt(const struct krb5_key_state *ks, struct mbuf *inout,
132 size_t skip, size_t len, void *ivec, size_t ivlen)
133 {
134 struct rc4_state rs;
135 uint8_t newkey[16];
136
137 arcfour_derive_key(ks, 0, newkey);
138
139 /*
140 * If we have an IV, then generate a new key from it using HMAC.
141 */
142 if (ivec) {
143 uint8_t kk[16];
144 arcfour_hmac(newkey, ivec, ivlen, kk);
145 rc4_init(&rs, kk, 16);
146 } else {
147 rc4_init(&rs, newkey, 16);
148 }
149
150 m_apply(inout, skip, len, rc4_crypt_int, &rs);
151 }
152
153 static int
MD5Update_int(void * ctx,void * buf,u_int len)154 MD5Update_int(void *ctx, void *buf, u_int len)
155 {
156
157 MD5Update(ctx, buf, len);
158 return (0);
159 }
160
161 static void
arcfour_checksum(const struct krb5_key_state * ks,int usage,struct mbuf * inout,size_t skip,size_t inlen,size_t outlen)162 arcfour_checksum(const struct krb5_key_state *ks, int usage,
163 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen)
164 {
165 MD5_CTX md5;
166 uint8_t Ksign[16];
167 uint8_t t[4];
168 uint8_t sgn_cksum[16];
169
170 arcfour_hmac(ks->ks_key, "signaturekey", 13, Ksign);
171
172 t[0] = usage >> 0;
173 t[1] = usage >> 8;
174 t[2] = usage >> 16;
175 t[3] = usage >> 24;
176
177 MD5Init(&md5);
178 MD5Update(&md5, t, 4);
179 m_apply(inout, skip, inlen, MD5Update_int, &md5);
180 MD5Final(sgn_cksum, &md5);
181
182 arcfour_hmac(Ksign, sgn_cksum, 16, sgn_cksum);
183 m_copyback(inout, skip + inlen, outlen, sgn_cksum);
184 }
185
186 struct krb5_encryption_class krb5_arcfour_encryption_class = {
187 "arcfour-hmac-md5", /* name */
188 ETYPE_ARCFOUR_HMAC_MD5, /* etype */
189 0, /* flags */
190 1, /* blocklen */
191 1, /* msgblocklen */
192 8, /* checksumlen */
193 128, /* keybits */
194 16, /* keylen */
195 arcfour_init,
196 arcfour_destroy,
197 arcfour_set_key,
198 arcfour_random_to_key,
199 arcfour_encrypt,
200 arcfour_encrypt,
201 arcfour_checksum
202 };
203
204 struct krb5_encryption_class krb5_arcfour_56_encryption_class = {
205 "arcfour-hmac-md5-56", /* name */
206 ETYPE_ARCFOUR_HMAC_MD5_56, /* etype */
207 0, /* flags */
208 1, /* blocklen */
209 1, /* msgblocklen */
210 8, /* checksumlen */
211 128, /* keybits */
212 16, /* keylen */
213 arcfour_init,
214 arcfour_destroy,
215 arcfour_set_key,
216 arcfour_random_to_key,
217 arcfour_encrypt,
218 arcfour_encrypt,
219 arcfour_checksum
220 };
221