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

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Revision 1.7 - (show annotations)
Thu Jun 20 08:49:23 2002 UTC (21 years, 9 months ago) by lefcha
Branch: MAIN
Changes since 1.6: +1 -0 lines
File MIME type: text/plain
Cipher CTX cleanup when failed.

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 c = ultostr(1 + random() % 100000000, 10);
66 memset(iv, '0', EVP_MAX_IV_LENGTH);
67 memcpy(iv + 8 - strlen(c), c, min(8, strlen(c)));
68
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 for (i = 0; i < mdl; i++)
96 snprintf(2 + buf + i * 2, ENCRYPTION_BUF - i * 2, "%02x", mdv[i]);
97
98 EVP_EncryptUpdate(&ctx, ebuf, &ebufl, buf, strlen(buf));
99 EVP_EncodeUpdate(&bctx, bbuf, &bbufl, ebuf, ebufl);
100 fwrite(bbuf, sizeof(char), bbufl, fd);
101
102 EVP_EncryptFinal(&ctx, ebuf, &ebufl);
103 EVP_EncodeUpdate(&bctx, bbuf, &bbufl, ebuf, ebufl);
104 EVP_EncodeFinal(&bctx, bbuf, &bbufl);
105
106 fwrite(bbuf, sizeof(char), bbufl, fd);
107
108 EVP_CIPHER_CTX_cleanup(&ctx);
109
110 return 0;
111 }
112
113
114 /*
115 * Decode (Base64) passwords, decrypt them and verify the MD5 checksum.
116 */
117 int decrypt_passwords(unsigned char **buf, FILE *fd)
118 {
119 int i, j = 1;
120 unsigned char iv[EVP_MAX_IV_LENGTH];
121 unsigned char *key;
122 unsigned char *c;
123 unsigned char ebuf[LINE_MAX];
124 unsigned char bbuf[LINE_MAX];
125 unsigned char mdv[EVP_MAX_MD_SIZE];
126 unsigned char mdc[EVP_MAX_MD_SIZE * 2 + 1];
127 int mdl, bufl, ebufl;
128 EVP_CIPHER_CTX *ctx;
129 EVP_MD_CTX mdctx;
130 EVP_ENCODE_CTX bctx;
131
132 c = *buf = (unsigned char *) smalloc(DECRYPTION_BUF * sizeof(char));
133 key = (unsigned char *) smalloc(EVP_MAX_KEY_LENGTH);
134 ctx = (EVP_CIPHER_CTX *) smalloc(sizeof(EVP_CIPHER_CTX));
135
136 fgets(bbuf, LINE_MAX, fd);
137
138 memcpy(iv, bbuf, EVP_MAX_IV_LENGTH);
139
140 EVP_CIPHER_CTX_init(ctx);
141
142 EVP_BytesToKey(EVP_bf_cbc(), EVP_md5(), NULL, passphr, strlen(passphr),
143 1, key, NULL);
144
145 EVP_DecryptInit(ctx, EVP_bf_cbc(), key, iv);
146 EVP_DecodeInit(&bctx);
147
148 while (fgets(bbuf, LINE_MAX, fd)) {
149 EVP_DecodeUpdate(&bctx, ebuf, &ebufl, bbuf, strlen(bbuf));
150 if (!EVP_DecryptUpdate(ctx, c, &bufl, ebuf, ebufl))
151 goto fail;
152
153 c += bufl;
154 *c = 0;
155
156 if (c - *buf > DECRYPTION_BUF * j - 64) {
157 i = c - *buf;
158 *buf = (char *) srealloc(*buf, DECRYPTION_BUF * ++j);
159 c = *buf + i;
160 *c = 0;
161 }
162 }
163
164 EVP_DecodeFinal(&bctx, ebuf, &ebufl);
165 if (!EVP_DecryptFinal(ctx, c, &bufl))
166 goto fail;
167
168 c += bufl;
169 *c = 0;
170
171 if (!(c = strstr(*buf, "\n.\n")))
172 goto fail;
173
174 EVP_DigestInit(&mdctx, EVP_md5());
175 EVP_DigestUpdate(&mdctx, *buf, c - *buf + 1);
176 EVP_DigestFinal(&mdctx, mdv, &mdl);
177
178 for (i = 0; i < mdl; i++)
179 snprintf(mdc + i * 2, EVP_MAX_MD_SIZE * 2 + 1 - i * 2, "%02x", mdv[i]);
180
181 c += 3;
182
183 if (strncmp(c, mdc, 32))
184 goto fail;
185
186 EVP_CIPHER_CTX_cleanup(ctx);
187
188 sfree(key);
189 sfree(ctx);
190
191 return 0;
192
193 fail:
194 error("Wrong master passphrase.\n");
195 EVP_CIPHER_CTX_cleanup(ctx);
196 sfree(*buf);
197 sfree(key);
198 sfree(ctx);
199
200 return ERROR_DECRYPT;
201 }
202
203
204 /*
205 * Interactive encrypted passwords editor.
206 */
207 void password_editor(void)
208 {
209 int i, q, n;
210 char buf[LINE_MAX];
211 char *c;
212 char *p[2];
213 account_t *a, *accts[EDITOR_PASSWORDS_MAX];
214
215 if (!(flags & FLAG_BLANK_PASSWORD)) {
216 error("imapfilter: no candidate passwords for encryption found\n");
217 return;
218 }
219
220 q = 0;
221
222 memset(accts, 0, EDITOR_PASSWORDS_MAX);
223
224 for (i = 0, a = accounts; i < EDITOR_PASSWORDS_MAX - 1 && a; a = a->next) {
225 if (a->passwdattr == PASSWORD_NONE ||
226 a->passwdattr == PASSWORD_ENCRYPTED)
227 accts[i++] = a;
228 }
229
230 do {
231 printf("command: ");
232 fgets(buf, LINE_MAX, stdin);
233 c = buf;
234 for (;; c++) {
235 if (*c == ' ' || *c == '\t')
236 continue;
237 else if (*c == '?' || *c == 'h')
238 printf("c clear a password entry\n"
239 "e edit a password entry\n"
240 "h help\n"
241 "l list entries\n"
242 "p change master password\n"
243 "q quit without saving\n"
244 "s save changes\n"
245 "x save and exit\n");
246 else if (*c == 'q')
247 q = 1;
248 else if (*c == 'l')
249 for (i = 0; accts[i]; i++)
250 printf("%d %s %s %s\n", i + 1, accts[i]->server,
251 accts[i]->username, accts[i]->password);
252 else if (*c == 'e') {
253 n = atoi(++c);
254 if (!n || n < 1 || n > 128 || !accts[n - 1])
255 break;
256 accts[n - 1]->password[0] = 0;
257 printf("Enter new password: ");
258 if (fgets(accts[n - 1]->password, PASSWORD_LEN, stdin))
259 if ((c = strchr(accts[n - 1]->password, '\n')))
260 *c = 0;
261 } else if (*c == 'c') {
262 n = atoi(++c);
263 if (!n || n < 1 || n > 128 || !accts[n - 1])
264 break;
265 accts[n - 1]->password[0] = 0;
266 } else if (*c == 'p') {
267 p[0] = (char *) smalloc(PASSPHRASE_LEN);
268 p[1] = (char *) smalloc(PASSPHRASE_LEN);
269 do {
270 for (i = 0; i < 2; i++) {
271 printf("Enter %snew master password: ",
272 i ? "again " : "");
273 get_password(p[i], PASSPHRASE_LEN);
274 }
275 } while (strcmp(p[0], p[1]));
276 xstrncpy(passphr, p[0], PASSPHRASE_LEN - 1);
277 sfree(p[0]);
278 sfree(p[1]);
279 } else if (*c == 's') {
280 store_passwords(accts);
281 } else if (*c == 'x') {
282 store_passwords(accts);
283 q = 1;
284 } else
285 break;
286 }
287 } while (!q);
288 }
289 #endif

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