Commit | Line | Data |
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9da480be MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Policy parsing and implementation | |
4 | * | |
5 | * (c) 2012 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
10 | * This file is part of Yet Another Ident Daemon (YAID). | |
11 | * | |
12 | * YAID is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License as published by | |
14 | * the Free Software Foundation; either version 2 of the License, or | |
15 | * (at your option) any later version. | |
16 | * | |
17 | * YAID is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with YAID; if not, write to the Free Software Foundation, | |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | */ | |
26 | ||
27 | /*----- Header files ------------------------------------------------------*/ | |
28 | ||
29 | #include "yaid.h" | |
30 | ||
c3794524 | 31 | /*----- Memory management -------------------------------------------------*/ |
9da480be | 32 | |
c3794524 MW |
33 | /* Initialize a policy structure. In this state, it doesn't actually have |
34 | * any resources allocated (so can be simply discarded) but it's safe to free | |
35 | * (using `free_policy'). | |
9da480be | 36 | */ |
9da480be MW |
37 | void init_policy(struct policy *p) { p->act.act = A_LIMIT; } |
38 | ||
c3794524 MW |
39 | /* Free an action structure, resetting it to a safe state. This function is |
40 | * idempotent. | |
41 | */ | |
9da480be MW |
42 | static void free_action(struct action *a) |
43 | { | |
44 | switch (a->act) { | |
45 | case A_LIE: | |
46 | xfree(a->u.lie); | |
47 | break; | |
48 | } | |
49 | a->act = A_LIMIT; | |
50 | } | |
51 | ||
c3794524 MW |
52 | /* Free a policy structure, resetting it to its freshly-initialized state. |
53 | * This function is idempotent. | |
54 | */ | |
9da480be MW |
55 | void free_policy(struct policy *p) |
56 | { free_action(&p->act); } | |
57 | ||
c3794524 MW |
58 | /*----- Diagnostics -------------------------------------------------------*/ |
59 | ||
bf4d9761 | 60 | static void print_addrpat(const struct addrops *ao, const struct addrpat *ap) |
9da480be MW |
61 | { |
62 | char buf[ADDRLEN]; | |
63 | ||
bf4d9761 MW |
64 | if (ap->len == 0) |
65 | putchar('*'); | |
66 | else { | |
67 | printf("%s/%u", | |
68 | inet_ntop(ao->af, &ap->addr, buf, sizeof(buf)), | |
69 | ap->len); | |
70 | } | |
9da480be MW |
71 | } |
72 | ||
73 | static void print_portpat(const struct portpat *pp) | |
74 | { | |
75 | if (pp->lo == 0 && pp->hi == 65535) putchar('*'); | |
76 | else if (pp->lo == pp->hi) printf("%u", pp->lo); | |
77 | else printf("%u-%u", pp->lo, pp->hi); | |
78 | } | |
79 | ||
bf4d9761 MW |
80 | static void print_sockpat(const struct addrops *ao, const struct sockpat *sp) |
81 | { print_addrpat(ao, &sp->addr); putchar(' '); print_portpat(&sp->port); } | |
9da480be MW |
82 | |
83 | static const char *const acttab[] = { | |
84 | #define DEFACT(tag, name) name, | |
85 | ACTIONS(DEFACT) | |
86 | #undef DEFACT | |
87 | 0 | |
88 | }; | |
89 | ||
90 | static void print_action(const struct action *act) | |
91 | { | |
92 | assert(act->act < A_LIMIT); | |
93 | printf("%s", acttab[act->act]); | |
94 | switch (act->act) { | |
95 | case A_USER: { | |
96 | int i; | |
97 | unsigned m; | |
98 | for (i = 0, m = 1; i < A_LIMIT; i++, m <<= 1) | |
99 | if (act->u.user & m) printf(" %s", acttab[i]); | |
100 | } break; | |
101 | case A_LIE: | |
102 | printf(" %s", act->u.lie); | |
103 | break; | |
104 | } | |
105 | } | |
106 | ||
c3794524 | 107 | /* Print a policy rule to standard output. */ |
9da480be MW |
108 | void print_policy(const struct policy *p) |
109 | { | |
bf4d9761 MW |
110 | print_sockpat(p->ao, &p->sp[L]); putchar(' '); |
111 | print_sockpat(p->ao, &p->sp[R]); putchar(' '); | |
9da480be MW |
112 | print_action(&p->act); putchar('\n'); |
113 | } | |
114 | ||
c3794524 MW |
115 | /*----- Matching ----------------------------------------------------------*/ |
116 | ||
117 | /* Return true if the port matches the pattern. */ | |
9da480be MW |
118 | static int match_portpat(const struct portpat *pp, unsigned port) |
119 | { return (pp->lo <= port && port <= pp->hi); } | |
120 | ||
c3794524 | 121 | /* Return true if the socket matches the pattern. */ |
bf4d9761 MW |
122 | static int match_sockpat(const struct addrops *ao, |
123 | const struct sockpat *sp, const struct socket *s) | |
9da480be | 124 | { |
bf4d9761 | 125 | return (ao->match_addrpat(&sp->addr, &s->addr) && |
9da480be MW |
126 | match_portpat(&sp->port, s->port)); |
127 | } | |
128 | ||
c3794524 | 129 | /* Return true if the query matches the patterns in the policy rule. */ |
9da480be MW |
130 | int match_policy(const struct policy *p, const struct query *q) |
131 | { | |
bf4d9761 MW |
132 | return ((!p->ao || p->ao == q->ao) && |
133 | match_sockpat(q->ao, &p->sp[L], &q->s[L]) && | |
134 | match_sockpat(q->ao, &p->sp[R], &q->s[R])); | |
9da480be MW |
135 | } |
136 | ||
c3794524 MW |
137 | /*----- Parsing -----------------------------------------------------------*/ |
138 | ||
139 | /* Advance FP to the next line. */ | |
9da480be MW |
140 | static void nextline(FILE *fp) |
141 | { | |
142 | for (;;) { | |
143 | int ch = getc(fp); | |
144 | if (ch == '\n' || ch == EOF) break; | |
145 | } | |
146 | } | |
147 | ||
c3794524 MW |
148 | /* Scan a whitespace-separated token from FP, writing it to BUF. The token |
149 | * must fit in a buffer of size SZ, including a terminating null. Return | |
150 | * an appropriate T_* error code. | |
151 | */ | |
9da480be MW |
152 | static int scan(FILE *fp, char *buf, size_t sz) |
153 | { | |
154 | int ch; | |
155 | ||
156 | skip_ws: | |
c3794524 | 157 | /* Before we start grabbing a token proper, find out what's in store. */ |
9da480be MW |
158 | ch = getc(fp); |
159 | switch (ch) { | |
c3794524 | 160 | |
9da480be MW |
161 | case '\n': |
162 | newline: | |
c3794524 | 163 | /* Found a newline. Leave it where it is and report it. */ |
9da480be MW |
164 | ungetc(ch, fp); |
165 | return (T_EOL); | |
c3794524 | 166 | |
9da480be MW |
167 | case EOF: |
168 | eof: | |
c3794524 | 169 | /* Found end-of-file, or an I/O error. Return an appropriate code. */ |
9da480be | 170 | return (ferror(fp) ? T_ERROR : T_EOF); |
c3794524 | 171 | |
9da480be | 172 | case '#': |
c3794524 MW |
173 | /* Found a comment. Consume it, and continue appropriately: it must |
174 | * be terminated either by a newline or end-of-file. | |
175 | */ | |
9da480be MW |
176 | for (;;) { |
177 | ch = getc(fp); | |
178 | if (ch == '\n') goto newline; | |
179 | else if (ch == EOF) goto eof; | |
180 | } | |
c3794524 | 181 | |
9da480be | 182 | default: |
c3794524 MW |
183 | /* Whitespace means we just continue around. Anything else and we |
184 | * start snarfing. | |
185 | */ | |
9da480be MW |
186 | if (isspace(ch)) goto skip_ws; |
187 | break; | |
188 | } | |
189 | ||
190 | for (;;) { | |
c3794524 MW |
191 | |
192 | /* If there's buffer space left, store the character. */ | |
9da480be | 193 | if (sz) { *buf++ = ch; sz--; } |
c3794524 MW |
194 | |
195 | /* Get a new one, and find out what to do about it. */ | |
9da480be MW |
196 | ch = getc(fp); |
197 | switch (ch) { | |
198 | case '\n': | |
199 | ungetc(ch, fp); | |
200 | goto done; | |
201 | case EOF: | |
202 | goto done; | |
203 | default: | |
204 | if (isspace(ch)) goto done; | |
205 | break; | |
206 | } | |
207 | } | |
208 | ||
209 | done: | |
c3794524 MW |
210 | /* If there's no space for a terminating null then report an error. */ |
211 | if (!sz) return (T_ERROR); | |
212 | ||
213 | /* All done. */ | |
214 | *buf++ = 0; sz--; | |
215 | return (T_OK); | |
9da480be MW |
216 | } |
217 | ||
c3794524 MW |
218 | /* Parse an action name, storing the code in *ACT. Return an appropriate T_* |
219 | * code. | |
220 | */ | |
9da480be MW |
221 | static int parse_actname(FILE *fp, unsigned *act) |
222 | { | |
223 | char buf[32]; | |
224 | int t; | |
225 | const char *const *p; | |
226 | ||
227 | if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t); | |
228 | for (p = acttab; *p; p++) | |
229 | if (strcmp(buf, *p) == 0) { *act = p - acttab; return (0); } | |
230 | return (T_ERROR); | |
231 | } | |
232 | ||
c3794524 | 233 | /* Parse an action, returning a T_* code. */ |
9da480be MW |
234 | static int parse_action(FILE *fp, struct action *act) |
235 | { | |
236 | char buf[32]; | |
237 | int t; | |
238 | unsigned a; | |
239 | unsigned long m; | |
240 | ||
c3794524 | 241 | /* Collect the action name. */ |
9da480be | 242 | if ((t = parse_actname(fp, &a)) != 0) return (t); |
c3794524 MW |
243 | |
244 | /* Parse parameters, if there are any. */ | |
9da480be | 245 | switch (a) { |
c3794524 | 246 | |
9da480be | 247 | case A_USER: |
c3794524 | 248 | /* `user ACTION ACTION ...': store permitted actions in a bitmask. */ |
9da480be MW |
249 | m = 0; |
250 | for (;;) { | |
251 | if ((t = parse_actname(fp, &a)) != 0) break; | |
252 | m |= (1 << a); | |
253 | } | |
254 | if (t != T_EOL && t != T_EOF) return (t); | |
255 | act->act = A_USER; | |
256 | act->u.user = m; | |
257 | break; | |
c3794524 | 258 | |
9da480be MW |
259 | case A_TOKEN: |
260 | case A_NAME: | |
261 | case A_DENY: | |
262 | case A_HIDE: | |
c3794524 | 263 | /* Dull actions which don't accept parameters. */ |
9da480be MW |
264 | act->act = a; |
265 | break; | |
c3794524 | 266 | |
9da480be | 267 | case A_LIE: |
c3794524 | 268 | /* `lie NAME': store the string we're to report. */ |
9da480be MW |
269 | if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t); |
270 | act->act = a; | |
271 | act->u.lie = xstrdup(buf); | |
272 | break; | |
273 | } | |
c3794524 MW |
274 | |
275 | /* Make sure we've reached the end of the line. */ | |
9da480be MW |
276 | t = scan(fp, buf, sizeof(buf)); |
277 | if (t != T_EOF && t != T_EOL) { | |
278 | free_action(act); | |
279 | return (T_ERROR); | |
280 | } | |
c3794524 MW |
281 | |
282 | /* Done. */ | |
9da480be MW |
283 | return (0); |
284 | } | |
285 | ||
c3794524 MW |
286 | /* Parse an address pattern, writing it to AP. If the pattern has an |
287 | * identifiable address family, update *AOP to point to its operations table; | |
288 | * if *AOP is already set to something different then report an error. | |
289 | */ | |
290 | static int parse_addrpat(FILE *fp, const struct addrops **aop, | |
291 | struct addrpat *ap) | |
9da480be MW |
292 | { |
293 | char buf[64]; | |
294 | int t; | |
bf4d9761 | 295 | const struct addrops *ao; |
9da480be MW |
296 | long n; |
297 | char *delim; | |
298 | ||
c3794524 | 299 | /* Scan a token for the address pattern. */ |
9da480be | 300 | if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t); |
c3794524 MW |
301 | |
302 | /* If this is a wildcard, then leave everything as it is. */ | |
303 | if (strcmp(buf, "*") == 0) { | |
304 | ap->len = 0; | |
305 | return (T_OK); | |
9da480be MW |
306 | } |
307 | ||
c3794524 MW |
308 | /* Decide what kind of address this must be. A bit grim, sorry. */ |
309 | if (strchr(buf, ':')) | |
310 | ao = &addroptab[ADDR_IPV6]; | |
311 | else | |
312 | ao = &addroptab[ADDR_IPV4]; | |
313 | ||
314 | /* Update the caller's idea of the address family in use. */ | |
315 | if (!*aop) *aop = ao; | |
316 | else if (*aop != ao) return (T_ERROR); | |
317 | ||
318 | /* See whether there's a prefix length. If so, clobber it. */ | |
319 | delim = strchr(buf, '/'); | |
320 | if (delim) *delim++ = 0; | |
321 | ||
322 | /* Parse the address. */ | |
323 | if (!inet_pton(ao->af, buf, &ap->addr)) return (T_ERROR); | |
324 | ||
325 | /* Parse the prefix length, or use the maximum one. */ | |
326 | if (!delim) n = ao->len; | |
327 | else n = strtol(delim, 0, 10); | |
328 | if (n < 0 || n > ao->len) return (T_ERROR); | |
329 | ap->len = n; | |
330 | ||
331 | /* Done. */ | |
332 | return (T_OK); | |
333 | } | |
334 | ||
335 | static int parse_portpat(FILE *fp, struct portpat *pp) | |
336 | { | |
337 | char buf[64]; | |
338 | int t; | |
339 | long n; | |
340 | char *delim; | |
341 | ||
342 | /* Parse a token for the pattern. */ | |
9da480be | 343 | if ((t = scan(fp, buf, sizeof(buf))) != 0) return (T_ERROR); |
c3794524 MW |
344 | |
345 | /* If this is a wildcard, then we're done. */ | |
9da480be | 346 | if (strcmp(buf, "*") == 0) { |
c3794524 MW |
347 | pp->lo = 0; |
348 | pp->hi = 65535; | |
349 | return (T_OK); | |
9da480be | 350 | } |
c3794524 MW |
351 | |
352 | /* Find a range delimiter. */ | |
353 | delim = strchr(buf, '-'); | |
354 | if (delim) *delim++ = 0; | |
355 | ||
356 | /* Parse the only or low end of the range. */ | |
357 | n = strtol(buf, 0, 0); | |
358 | if (n < 0 || n > 65535) return (T_ERROR); | |
359 | pp->lo = n; | |
360 | ||
361 | /* If there's no delimiter, then the high end is equal to the low end; | |
362 | * otherwise, parse the high end. | |
363 | */ | |
364 | if (!delim) | |
365 | pp->hi = n; | |
366 | else { | |
367 | n = strtol(delim, 0, 0); | |
368 | if (n < pp->lo || n > 65535) return (T_ERROR); | |
369 | pp->hi = n; | |
370 | } | |
371 | ||
372 | /* Done. */ | |
373 | return (T_OK); | |
9da480be MW |
374 | } |
375 | ||
c3794524 MW |
376 | /* Parse a socket pattern, writing it to SP. */ |
377 | static int parse_sockpat(FILE *fp, const struct addrops **aop, | |
378 | struct sockpat *sp) | |
379 | { | |
380 | int t; | |
381 | ||
382 | if ((t = parse_addrpat(fp, aop, &sp->addr)) != 0) return (t); | |
383 | if ((t = parse_portpat(fp, &sp->port)) != 0) return (T_ERROR); | |
384 | return (T_OK); | |
385 | } | |
386 | ||
387 | /* Parse a policy rule line, writing it to P. */ | |
388 | static int parse_policy(FILE *fp, struct policy *p) | |
9da480be MW |
389 | { |
390 | int t; | |
391 | ||
bf4d9761 | 392 | p->ao = 0; |
9da480be MW |
393 | free_policy(p); |
394 | ||
bf4d9761 MW |
395 | if ((t = parse_sockpat(fp, &p->ao, &p->sp[L])) != 0) goto fail; |
396 | if ((t = parse_sockpat(fp, &p->ao, &p->sp[R])) != 0) goto err; | |
9da480be MW |
397 | if ((t = parse_action(fp, &p->act)) != 0) goto err; |
398 | return (0); | |
399 | ||
400 | err: | |
401 | t = T_ERROR; | |
402 | fail: | |
403 | free_policy(p); | |
404 | return (t); | |
405 | } | |
406 | ||
c3794524 MW |
407 | /* Open a policy file by NAME. The description WHAT and query Q are used for |
408 | * formatting error messages for the log. | |
409 | */ | |
9da480be MW |
410 | int open_policy_file(struct policy_file *pf, const char *name, |
411 | const char *what, const struct query *q) | |
412 | { | |
413 | if ((pf->fp = fopen(name, "r")) == 0) { | |
414 | logmsg(q, LOG_ERR, "failed to open %s `%s': %s", | |
415 | what, name, strerror(errno)); | |
416 | return (-1); | |
417 | } | |
418 | ||
419 | pf->name = name; | |
420 | pf->what = what; | |
421 | pf->q = q; | |
422 | pf->err = 0; | |
423 | pf->lno = 0; | |
424 | init_policy(&pf->p); | |
425 | return (0); | |
426 | } | |
427 | ||
c3794524 MW |
428 | /* Read a policy rule from the file, storing it in PF->p. Return one of the |
429 | * T_* codes. | |
430 | */ | |
9da480be MW |
431 | int read_policy_file(struct policy_file *pf) |
432 | { | |
433 | int t; | |
434 | ||
435 | for (;;) { | |
436 | pf->lno++; | |
437 | t = parse_policy(pf->fp, &pf->p); | |
438 | switch (t) { | |
439 | case T_OK: | |
440 | nextline(pf->fp); | |
441 | return (0); | |
442 | case T_ERROR: | |
443 | logmsg(pf->q, LOG_ERR, "%s:%d: parse error in %s", | |
444 | pf->name, pf->lno, pf->what); | |
445 | pf->err = 1; | |
446 | break; | |
447 | case T_EOF: | |
448 | if (ferror(pf->fp)) { | |
449 | logmsg(pf->q, LOG_ERR, "failed to read %s `%s': %s", | |
450 | pf->what, pf->name, strerror(errno)); | |
451 | } | |
452 | return (-1); | |
453 | case T_EOL: | |
454 | nextline(pf->fp); | |
455 | break; | |
456 | default: | |
457 | abort(); | |
458 | } | |
459 | } | |
460 | } | |
461 | ||
c3794524 MW |
462 | /* Close a policy file. It doesn't matter whether the file was completely |
463 | * read. | |
464 | */ | |
9da480be MW |
465 | void close_policy_file(struct policy_file *pf) |
466 | { | |
467 | fclose(pf->fp); | |
468 | free_policy(&pf->p); | |
469 | } | |
470 | ||
c3794524 MW |
471 | /* Load a policy file, writing a vector of records into PV. If the policy |
472 | * file has errors, then leave PV unchanged and return nonzero. | |
473 | */ | |
9da480be MW |
474 | int load_policy_file(const char *file, policy_v *pv) |
475 | { | |
476 | struct policy_file pf; | |
477 | policy_v v = DA_INIT; | |
478 | ||
479 | if (open_policy_file(&pf, file, "policy file", 0)) | |
480 | return (-1); | |
481 | while (!read_policy_file(&pf)) { | |
482 | DA_PUSH(&v, pf.p); | |
483 | init_policy(&pf.p); | |
484 | } | |
485 | close_policy_file(&pf); | |
486 | if (!pf.err) { | |
487 | DA_DESTROY(pv); | |
488 | *pv = v; | |
489 | return (0); | |
490 | } else { | |
491 | DA_DESTROY(&v); | |
492 | return (-1); | |
493 | } | |
494 | } | |
495 | ||
496 | /*----- That's all, folks -------------------------------------------------*/ |