1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 #pragma ident "%Z%%M% %I% %E% SMI"
27
28 /*
29 * SMB MAC Signing support.
30 */
31
32 #include <strings.h>
33 #include <security/cryptoki.h>
34 #include <security/pkcs11.h>
35
36 #include <smbsrv/libsmb.h>
37
38 #include <smbsrv/smb.h>
39
40 /*
41 * smb_mac_init
42 *
43 * Calculates the MAC key using the specified user session
44 * key (NTLM or NTLMv2).
45 *
46 * Returns SMBAUTH_SUCCESS if key generation was successful,
47 * SMBAUTH_FAILURE if not.
48 */
49 int
smb_mac_init(smb_sign_ctx_t * sign_ctx,smb_auth_info_t * auth)50 smb_mac_init(smb_sign_ctx_t *sign_ctx, smb_auth_info_t *auth)
51 {
52 unsigned char S16[SMBAUTH_SESSION_KEY_SZ];
53
54 if (smb_auth_gen_session_key(auth, S16) != SMBAUTH_SUCCESS)
55 return (SMBAUTH_FAILURE);
56 bcopy(S16, sign_ctx->ssc_mackey, SMBAUTH_SESSION_KEY_SZ);
57 bcopy(auth->cs, &(sign_ctx->ssc_mackey[SMBAUTH_SESSION_KEY_SZ]),
58 auth->cs_len);
59 sign_ctx->ssc_keylen = SMBAUTH_SESSION_KEY_SZ + auth->cs_len;
60 return (SMBAUTH_SUCCESS);
61 }
62
63 /*
64 * smb_mac_calc
65 *
66 * Calculates MAC signature for the given buffer and returns
67 * it in the mac_sign parameter.
68 *
69 * The MAC signature is calculated as follows:
70 *
71 * data = concat(MAC_Key, MAC_Key_Len, SMB_Msg, SMB_Msg_Len);
72 * hash = MD5(data);
73 * MAC = head(hash, 8);
74 *
75 * The tricky part is that a sequence number should be used
76 * in calculation instead of the signature field in the
77 * SMB header.
78 *
79 * Returns SMBAUTH_SUCCESS if cryptology framework use was successful,
80 * SMBAUTH_FAILURE if not.
81 */
82 int
smb_mac_calc(smb_sign_ctx_t * sign_ctx,const unsigned char * buf,size_t buf_len,unsigned char * mac_sign)83 smb_mac_calc(smb_sign_ctx_t *sign_ctx, const unsigned char *buf,
84 size_t buf_len, unsigned char *mac_sign)
85 {
86 CK_RV rv;
87 CK_MECHANISM mechanism;
88 CK_SESSION_HANDLE hSession;
89 unsigned long diglen = MD_DIGEST_LEN;
90 int rc = SMBAUTH_FAILURE;
91
92 int offset_end_of_sig = (SMB_SIG_OFFS + SMB_SIG_SIZE);
93 unsigned char seq_buf[SMB_SIG_SIZE];
94 unsigned char mac[16];
95
96 /*
97 * put seq_num into the first 4 bytes and
98 * zero out the next 4 bytes
99 */
100 bcopy(&sign_ctx->ssc_seqnum, seq_buf, 4);
101 bzero(seq_buf + 4, 4);
102
103 mechanism.mechanism = CKM_MD5;
104 mechanism.pParameter = 0;
105 mechanism.ulParameterLen = 0;
106
107 rv = SUNW_C_GetMechSession(mechanism.mechanism, &hSession);
108 if (rv != CKR_OK)
109 return (SMBAUTH_FAILURE);
110
111 /* Initialize the digest operation in the session */
112 rv = C_DigestInit(hSession, &mechanism);
113 if (rv != CKR_OK)
114 goto smbmacdone;
115
116 /* init with the MAC key */
117 rv = C_DigestUpdate(hSession, sign_ctx->ssc_mackey,
118 sign_ctx->ssc_keylen);
119 if (rv != CKR_OK)
120 goto smbmacdone;
121
122 /* copy in SMB packet info till signature field */
123 rv = C_DigestUpdate(hSession, (CK_BYTE_PTR)buf, SMB_SIG_OFFS);
124 if (rv != CKR_OK)
125 goto smbmacdone;
126
127 /* copy in the seq_buf instead of the signature */
128 rv = C_DigestUpdate(hSession, seq_buf, sizeof (seq_buf));
129 if (rv != CKR_OK)
130 goto smbmacdone;
131
132 /* copy in the rest of the packet, skipping the signature */
133 rv = C_DigestUpdate(hSession, (CK_BYTE_PTR)buf + offset_end_of_sig,
134 buf_len - offset_end_of_sig);
135 if (rv != CKR_OK)
136 goto smbmacdone;
137
138 rv = C_DigestFinal(hSession, mac, &diglen);
139 if (rv != CKR_OK)
140 goto smbmacdone;
141
142 bcopy(mac, mac_sign, SMB_SIG_SIZE);
143 rc = SMBAUTH_SUCCESS;
144
145 smbmacdone:
146 (void) C_CloseSession(hSession);
147 return (rc);
148 }
149
150 /*
151 * smb_mac_chk
152 *
153 * Calculates MAC signature for the given buffer
154 * and compares it to the signature in the given context.
155 * Return 1 if the signature are match, otherwise, return (0);
156 */
157 int
smb_mac_chk(smb_sign_ctx_t * sign_ctx,const unsigned char * buf,size_t buf_len)158 smb_mac_chk(smb_sign_ctx_t *sign_ctx,
159 const unsigned char *buf, size_t buf_len)
160 {
161 unsigned char mac_sign[SMB_SIG_SIZE];
162
163 /* calculate mac signature */
164 if (smb_mac_calc(sign_ctx, buf, buf_len, mac_sign) != SMBAUTH_SUCCESS)
165 return (0);
166
167 /* compare the signatures */
168 if (memcmp(sign_ctx->ssc_sign, mac_sign, SMB_SIG_SIZE) == 0)
169 return (1);
170
171 return (0);
172 }
173
174 /*
175 * smb_mac_sign
176 *
177 * Calculates MAC signature for the given buffer,
178 * and write it to the buffer's signature field.
179 *
180 * Returns SMBAUTH_SUCCESS if cryptology framework use was successful,
181 * SMBAUTH_FAILURE if not.
182 */
183 int
smb_mac_sign(smb_sign_ctx_t * sign_ctx,unsigned char * buf,size_t buf_len)184 smb_mac_sign(smb_sign_ctx_t *sign_ctx, unsigned char *buf, size_t buf_len)
185 {
186 unsigned char mac_sign[SMB_SIG_SIZE];
187
188 /* calculate mac signature */
189 if (smb_mac_calc(sign_ctx, buf, buf_len, mac_sign) != SMBAUTH_SUCCESS)
190 return (SMBAUTH_FAILURE);
191
192 /* put mac signature in the header's signature field */
193 (void) memcpy(buf + SMB_SIG_OFFS, mac_sign, SMB_SIG_SIZE);
194 return (SMBAUTH_SUCCESS);
195 }
196
197 void
smb_mac_inc_seqnum(smb_sign_ctx_t * sign_ctx)198 smb_mac_inc_seqnum(smb_sign_ctx_t *sign_ctx)
199 {
200 sign_ctx->ssc_seqnum++;
201 }
202
203 void
smb_mac_dec_seqnum(smb_sign_ctx_t * sign_ctx)204 smb_mac_dec_seqnum(smb_sign_ctx_t *sign_ctx)
205 {
206 sign_ctx->ssc_seqnum--;
207 }
208