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DEFINITIONS
This source file includes following definitions.
- sess_crypt_blob
- sess_encrypt_string
- sess_decrypt_string
- sess_encrypt_blob
- sess_decrypt_blob
1 /*
2 Unix SMB/CIFS implementation.
3
4 code to encrypt/decrypt data using the user session key
5
6 Copyright (C) Andrew Tridgell 2004
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "includes.h"
23 #include "libcli/auth/libcli_auth.h"
24
25 /*
26 encrypt or decrypt a blob of data using the user session key
27 as used in lsa_SetSecret
28
29 before calling, the out blob must be initialised to be the same size
30 as the in blob
31 */
32 void sess_crypt_blob(DATA_BLOB *out, const DATA_BLOB *in, const DATA_BLOB *session_key,
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33 bool forward)
34 {
35 int i, k;
36
37 for (i=0,k=0;
38 i<in->length;
39 i += 8, k += 7) {
40 uint8_t bin[8], bout[8], key[7];
41
42 memset(bin, 0, 8);
43 memcpy(bin, &in->data[i], MIN(8, in->length-i));
44
45 if (k + 7 > session_key->length) {
46 k = (session_key->length - k);
47 }
48 memcpy(key, &session_key->data[k], 7);
49
50 des_crypt56(bout, bin, key, forward?1:0);
51
52 memcpy(&out->data[i], bout, MIN(8, in->length-i));
53 }
54 }
55
56
57 /*
58 a convenient wrapper around sess_crypt_blob() for strings, using the LSA convention
59
60 note that we round the length to a multiple of 8. This seems to be needed for
61 compatibility with windows
62
63 caller should free using data_blob_free()
64 */
65 DATA_BLOB sess_encrypt_string(const char *str, const DATA_BLOB *session_key)
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66 {
67 DATA_BLOB ret, src;
68 int slen = strlen(str);
69 int dlen = (slen+7) & ~7;
70
71 src = data_blob(NULL, 8+dlen);
72 if (!src.data) {
73 return data_blob(NULL, 0);
74 }
75
76 ret = data_blob(NULL, 8+dlen);
77 if (!ret.data) {
78 data_blob_free(&src);
79 return data_blob(NULL, 0);
80 }
81
82 SIVAL(src.data, 0, slen);
83 SIVAL(src.data, 4, 1);
84 memset(src.data+8, 0, dlen);
85 memcpy(src.data+8, str, slen);
86
87 sess_crypt_blob(&ret, &src, session_key, true);
88
89 data_blob_free(&src);
90
91 return ret;
92 }
93
94 /*
95 a convenient wrapper around sess_crypt_blob() for strings, using the LSA convention
96
97 caller should free the returned string
98 */
99 char *sess_decrypt_string(TALLOC_CTX *mem_ctx,
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100 DATA_BLOB *blob, const DATA_BLOB *session_key)
101 {
102 DATA_BLOB out;
103 int slen;
104 char *ret;
105
106 if (blob->length < 8) {
107 return NULL;
108 }
109
110 out = data_blob_talloc(mem_ctx, NULL, blob->length);
111 if (!out.data) {
112 return NULL;
113 }
114
115 sess_crypt_blob(&out, blob, session_key, false);
116
117 if (IVAL(out.data, 4) != 1) {
118 DEBUG(0,("Unexpected revision number %d in session crypted string\n",
119 IVAL(out.data, 4)));
120 data_blob_free(&out);
121 return NULL;
122 }
123
124 slen = IVAL(out.data, 0);
125 if (slen > blob->length - 8) {
126 DEBUG(0,("Invalid crypt length %d\n", slen));
127 data_blob_free(&out);
128 return NULL;
129 }
130
131 ret = talloc_strndup(mem_ctx, (const char *)(out.data+8), slen);
132
133 data_blob_free(&out);
134
135 DEBUG(0,("decrypted string '%s' of length %d\n", ret, slen));
136
137 return ret;
138 }
139
140 /*
141 a convenient wrapper around sess_crypt_blob() for DATA_BLOBs, using the LSA convention
142
143 note that we round the length to a multiple of 8. This seems to be needed for
144 compatibility with windows
145
146 caller should free using data_blob_free()
147 */
148 DATA_BLOB sess_encrypt_blob(TALLOC_CTX *mem_ctx, DATA_BLOB *blob_in, const DATA_BLOB *session_key)
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149 {
150 DATA_BLOB ret, src;
151 int dlen = (blob_in->length+7) & ~7;
152
153 src = data_blob_talloc(mem_ctx, NULL, 8+dlen);
154 if (!src.data) {
155 return data_blob(NULL, 0);
156 }
157
158 ret = data_blob_talloc(mem_ctx, NULL, 8+dlen);
159 if (!ret.data) {
160 data_blob_free(&src);
161 return data_blob(NULL, 0);
162 }
163
164 SIVAL(src.data, 0, blob_in->length);
165 SIVAL(src.data, 4, 1);
166 memset(src.data+8, 0, dlen);
167 memcpy(src.data+8, blob_in->data, blob_in->length);
168
169 sess_crypt_blob(&ret, &src, session_key, true);
170
171 data_blob_free(&src);
172
173 return ret;
174 }
175
176 /*
177 Decrypt a DATA_BLOB using the LSA convention
178 */
179 NTSTATUS sess_decrypt_blob(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob, const DATA_BLOB *session_key,
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180 DATA_BLOB *ret)
181 {
182 DATA_BLOB out;
183 int slen;
184
185 if (blob->length < 8) {
186 DEBUG(0, ("Unexpected length %d in session crypted secret (BLOB)\n",
187 (int)blob->length));
188 return NT_STATUS_INVALID_PARAMETER;
189 }
190
191 out = data_blob_talloc(mem_ctx, NULL, blob->length);
192 if (!out.data) {
193 return NT_STATUS_NO_MEMORY;
194 }
195
196 sess_crypt_blob(&out, blob, session_key, false);
197
198 if (IVAL(out.data, 4) != 1) {
199 DEBUG(2,("Unexpected revision number %d in session crypted secret (BLOB)\n",
200 IVAL(out.data, 4)));
201 return NT_STATUS_UNKNOWN_REVISION;
202 }
203
204 slen = IVAL(out.data, 0);
205 if (slen > blob->length - 8) {
206 DEBUG(0,("Invalid crypt length %d in session crypted secret (BLOB)\n", slen));
207 return NT_STATUS_WRONG_PASSWORD;
208 }
209
210 *ret = data_blob_talloc(mem_ctx, out.data+8, slen);
211 if (slen && !ret->data) {
212 return NT_STATUS_NO_MEMORY;
213 }
214
215 data_blob_free(&out);
216
217 return NT_STATUS_OK;
218 }