/[imapfilter]/imapfilter/passwd.c
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Contents of /imapfilter/passwd.c

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Revision 1.8 - (show annotations)
Sat Jul 13 22:31:37 2002 UTC (21 years, 8 months ago) by lefcha
Branch: MAIN
CVS Tags: release-0_8
Branch point for: release-0_8-patches
Changes since 1.7: +33 -31 lines
File MIME type: text/plain
Comments and stylistic changes.

1 #include <stdio.h>
2 #include <string.h>
3 #include <stdlib.h>
4 #include <limits.h>
5
6 #include "config.h"
7 #include "imapfilter.h"
8 #include "data.h"
9
10 #ifdef ENCRYPTED_PASSWORDS
11 #include <openssl/evp.h>
12 #endif
13
14
15 extern unsigned int flags;
16 extern account_t *accounts;
17
18 #ifdef ENCRYPTED_PASSWORDS
19 extern char *passphr;
20 #endif
21
22 /*
23 * Get password from user interactively.
24 */
25 void get_password(char *passwd, size_t pwlen)
26 {
27 char *c;
28
29 tty_disable_echo();
30
31 if (fgets(passwd, pwlen, stdin))
32 if ((c = strchr(passwd, '\n')))
33 *c = 0;
34
35 tty_restore();
36
37 putchar('\n');
38 }
39
40
41 #ifdef ENCRYPTED_PASSWORDS
42 /*
43 * Encrypt and Base64 encode passwords. Append the MD5 checksum of the passwords
44 * before encrypting them.
45 */
46 int encrypt_passwords(FILE * fd, account_t * accts[])
47 {
48 int i;
49 char *c;
50 unsigned char iv[EVP_MAX_IV_LENGTH];
51 unsigned char *key;
52 unsigned char buf[ENCRYPTION_BUF];
53 unsigned char ebuf[ENCRYPTION_BUF];
54 unsigned char bbuf[ENCRYPTION_BUF];
55 unsigned char mdv[EVP_MAX_MD_SIZE];
56 int mdl, ebufl, bbufl;
57 EVP_CIPHER_CTX ctx;
58 EVP_MD_CTX mdctx;
59 EVP_ENCODE_CTX bctx;
60
61 key = (unsigned char *)smalloc(EVP_MAX_KEY_LENGTH);
62
63 srandom(time(NULL));
64
65 /* Initialization vector. */
66 c = ultostr(1 + random() % 100000000, 10);
67 memset(iv, '0', EVP_MAX_IV_LENGTH);
68 memcpy(iv + 8 - strlen(c), c, min(8, strlen(c)));
69 fprintf(fd, "%.8s\n", iv);
70
71 EVP_CIPHER_CTX_init(&ctx);
72
73 EVP_BytesToKey(EVP_bf_cbc(), EVP_md5(), NULL, passphr, strlen(passphr), 1,
74 key, NULL);
75
76 EVP_DigestInit(&mdctx, EVP_md5());
77 EVP_EncryptInit(&ctx, EVP_bf_cbc(), key, iv);
78 EVP_EncodeInit(&bctx);
79
80 for (i = 0; accts[i]; i++) {
81 snprintf(buf, ENCRYPTION_BUF, "%s %s %s\n", accts[i]->server, accts[i]->username,
82 accts[i]->password);
83
84 EVP_DigestUpdate(&mdctx, buf, strlen(buf));
85 EVP_EncryptUpdate(&ctx, ebuf, &ebufl, buf, strlen(buf));
86 EVP_EncodeUpdate(&bctx, bbuf, &bbufl, ebuf, ebufl);
87
88 fwrite(bbuf, sizeof(char), bbufl, fd);
89 }
90
91 EVP_DigestFinal(&mdctx, mdv, &mdl);
92
93 xstrncpy(buf, ".\n", ENCRYPTION_BUF - 1);
94
95 /* MD5 checksum of data. */
96 for (i = 0; i < mdl; i++)
97 snprintf(2 + buf + i * 2, ENCRYPTION_BUF - i * 2, "%02x", mdv[i]);
98
99 EVP_EncryptUpdate(&ctx, ebuf, &ebufl, buf, strlen(buf));
100 EVP_EncodeUpdate(&bctx, bbuf, &bbufl, ebuf, ebufl);
101 fwrite(bbuf, sizeof(char), bbufl, fd);
102
103 EVP_EncryptFinal(&ctx, ebuf, &ebufl);
104 EVP_EncodeUpdate(&bctx, bbuf, &bbufl, ebuf, ebufl);
105 EVP_EncodeFinal(&bctx, bbuf, &bbufl);
106
107 fwrite(bbuf, sizeof(char), bbufl, fd);
108
109 EVP_CIPHER_CTX_cleanup(&ctx);
110
111 return 0;
112 }
113
114
115 /*
116 * Decode (Base64) passwords, decrypt them and verify the MD5 checksum.
117 */
118 int decrypt_passwords(unsigned char **buf, FILE * fd)
119 {
120 int i, j = 1;
121 unsigned char iv[EVP_MAX_IV_LENGTH];
122 unsigned char *key;
123 unsigned char *c;
124 unsigned char ebuf[LINE_MAX];
125 unsigned char bbuf[LINE_MAX];
126 unsigned char mdv[EVP_MAX_MD_SIZE];
127 unsigned char mdc[EVP_MAX_MD_SIZE * 2 + 1];
128 int mdl, bufl, ebufl;
129 EVP_CIPHER_CTX *ctx;
130 EVP_MD_CTX mdctx;
131 EVP_ENCODE_CTX bctx;
132
133 c = *buf = (unsigned char *)smalloc(DECRYPTION_BUF * sizeof(char));
134 key = (unsigned char *)smalloc(EVP_MAX_KEY_LENGTH);
135 ctx = (EVP_CIPHER_CTX *) smalloc(sizeof(EVP_CIPHER_CTX));
136
137 fgets(bbuf, LINE_MAX, fd);
138
139 memcpy(iv, bbuf, EVP_MAX_IV_LENGTH);
140
141 EVP_CIPHER_CTX_init(ctx);
142
143 EVP_BytesToKey(EVP_bf_cbc(), EVP_md5(), NULL, passphr, strlen(passphr),
144 1, key, NULL);
145
146 EVP_DecryptInit(ctx, EVP_bf_cbc(), key, iv);
147 EVP_DecodeInit(&bctx);
148
149 while (fgets(bbuf, LINE_MAX, fd)) {
150 EVP_DecodeUpdate(&bctx, ebuf, &ebufl, bbuf, strlen(bbuf));
151 if (!EVP_DecryptUpdate(ctx, c, &bufl, ebuf, ebufl))
152 goto fail;
153
154 c += bufl;
155 *c = 0;
156
157 if (c - *buf > DECRYPTION_BUF * j - 64) {
158 i = c - *buf;
159 *buf = (char *)srealloc(*buf, DECRYPTION_BUF * ++j);
160 c = *buf + i;
161 *c = 0;
162 }
163 }
164
165 EVP_DecodeFinal(&bctx, ebuf, &ebufl);
166 if (!EVP_DecryptFinal(ctx, c, &bufl))
167 goto fail;
168
169 c += bufl;
170 *c = 0;
171
172 /* Calculate the MD5 checksum and check if it is correct. */
173 if (!(c = strstr(*buf, "\n.\n")))
174 goto fail;
175
176 EVP_DigestInit(&mdctx, EVP_md5());
177 EVP_DigestUpdate(&mdctx, *buf, c - *buf + 1);
178 EVP_DigestFinal(&mdctx, mdv, &mdl);
179
180 for (i = 0; i < mdl; i++)
181 snprintf(mdc + i * 2, EVP_MAX_MD_SIZE * 2 + 1 - i * 2, "%02x", mdv[i]);
182
183 c += 3;
184
185 if (strncmp(c, mdc, 32))
186 goto fail;
187
188 EVP_CIPHER_CTX_cleanup(ctx);
189
190 sfree(key);
191 sfree(ctx);
192
193 return 0;
194
195 fail:
196 error("Wrong master passphrase.\n");
197 EVP_CIPHER_CTX_cleanup(ctx);
198 sfree(*buf);
199 sfree(key);
200 sfree(ctx);
201
202 return ERROR_DECRYPT;
203 }
204
205
206 /*
207 * Interactive encrypted passwords editor.
208 */
209 void password_editor(void)
210 {
211 int i, q, n;
212 char buf[LINE_MAX];
213 char *c;
214 char *p[2];
215 account_t *a, *accts[EDITOR_PASSWORDS_MAX];
216
217 if (!(flags & FLAG_BLANK_PASSWORD)) {
218 error("imapfilter: no candidate passwords for encryption found\n");
219 return;
220 }
221 q = 0;
222
223 memset(accts, 0, EDITOR_PASSWORDS_MAX);
224
225 for (i = 0, a = accounts; i < EDITOR_PASSWORDS_MAX - 1 && a; a = a->next) {
226 if (a->passwdattr == PASSWORD_NONE ||
227 a->passwdattr == PASSWORD_ENCRYPTED)
228 accts[i++] = a;
229 }
230
231 do {
232 printf("command: ");
233 fgets(buf, LINE_MAX, stdin);
234 c = buf;
235 for (;; c++) {
236 if (*c == ' ' || *c == '\t')
237 continue;
238 else if (*c == '?' || *c == 'h')
239 printf("c clear a password entry\n"
240 "e edit a password entry\n"
241 "h help\n"
242 "l list entries\n"
243 "p change master password\n"
244 "q quit without saving\n"
245 "s save changes\n"
246 "x save and exit\n");
247 else if (*c == 'q')
248 q = 1;
249 else if (*c == 'l')
250 for (i = 0; accts[i]; i++)
251 printf("%d %s %s %s\n", i + 1, accts[i]->server,
252 accts[i]->username, accts[i]->password);
253 else if (*c == 'e') {
254 n = atoi(++c);
255 if (!n || n < 1 || n > 128 || !accts[n - 1])
256 break;
257 accts[n - 1]->password[0] = 0;
258 printf("Enter new password: ");
259 if (fgets(accts[n - 1]->password, PASSWORD_LEN, stdin))
260 if ((c = strchr(accts[n - 1]->password, '\n')))
261 *c = 0;
262 } else if (*c == 'c') {
263 n = atoi(++c);
264 if (!n || n < 1 || n > 128 || !accts[n - 1])
265 break;
266 accts[n - 1]->password[0] = 0;
267 } else if (*c == 'p') {
268 p[0] = (char *)smalloc(PASSPHRASE_LEN);
269 p[1] = (char *)smalloc(PASSPHRASE_LEN);
270 do {
271 for (i = 0; i < 2; i++) {
272 printf("Enter %snew master password: ",
273 i ? "again " : "");
274 get_password(p[i], PASSPHRASE_LEN);
275 }
276 } while (strcmp(p[0], p[1]));
277 xstrncpy(passphr, p[0], PASSPHRASE_LEN - 1);
278 sfree(p[0]);
279 sfree(p[1]);
280 } else if (*c == 's') {
281 store_passwords(accts);
282 } else if (*c == 'x') {
283 store_passwords(accts);
284 q = 1;
285 } else
286 break;
287 }
288 } while (!q);
289 }
290
291 #endif

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