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1 | /* | |
2 | * Zebra privileges. | |
3 | * | |
4 | * Copyright (C) 2003 Paul Jakma. | |
5 | * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved. | |
6 | * | |
7 | * This file is part of GNU Zebra. | |
8 | * | |
9 | * GNU Zebra is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation; either version 2, or (at your option) any | |
12 | * later version. | |
13 | * | |
14 | * GNU Zebra is distributed in the hope that it will be useful, but | |
15 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License along | |
20 | * with this program; see the file COPYING; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | #include <zebra.h> | |
24 | #include "log.h" | |
25 | #include "privs.h" | |
26 | #include "memory.h" | |
27 | #include "frr_pthread.h" | |
28 | #include "lib_errors.h" | |
29 | #include "lib/queue.h" | |
30 | ||
31 | DEFINE_MTYPE_STATIC(LIB, PRIVS, "Privilege information"); | |
32 | ||
33 | /* | |
34 | * Different capabilities/privileges apis have different characteristics: some | |
35 | * are process-wide, and some are per-thread. | |
36 | */ | |
37 | #ifdef HAVE_CAPABILITIES | |
38 | #ifdef HAVE_LCAPS | |
39 | static const bool privs_per_process; /* = false */ | |
40 | #else | |
41 | static const bool privs_per_process = true; | |
42 | #endif /* HAVE_LCAPS */ | |
43 | #else /* HAVE_CAPABILITIES */ | |
44 | static const bool privs_per_process = true; | |
45 | #endif | |
46 | ||
47 | #ifdef HAVE_CAPABILITIES | |
48 | ||
49 | /* sort out some generic internal types for: | |
50 | * | |
51 | * privilege values (cap_value_t, priv_t) -> pvalue_t | |
52 | * privilege set (..., priv_set_t) -> pset_t | |
53 | * privilege working storage (cap_t, ...) -> pstorage_t | |
54 | * | |
55 | * values we think of as numeric (they're ints really, but we dont know) | |
56 | * sets are mostly opaque, to hold a set of privileges, related in some way. | |
57 | * storage binds together a set of sets we're interested in. | |
58 | * (in reality: cap_value_t and priv_t are ints) | |
59 | */ | |
60 | #ifdef HAVE_LCAPS | |
61 | /* Linux doesn't have a 'set' type: a set of related privileges */ | |
62 | struct _pset { | |
63 | int num; | |
64 | cap_value_t *caps; | |
65 | }; | |
66 | typedef cap_value_t pvalue_t; | |
67 | typedef struct _pset pset_t; | |
68 | typedef cap_t pstorage_t; | |
69 | ||
70 | #else /* no LCAPS */ | |
71 | #error "HAVE_CAPABILITIES defined, but neither LCAPS nor Solaris Capabilties!" | |
72 | #endif /* HAVE_LCAPS */ | |
73 | #endif /* HAVE_CAPABILITIES */ | |
74 | ||
75 | /* the default NULL state we report is RAISED, but could be LOWERED if | |
76 | * zprivs_terminate is called and the NULL handler is installed. | |
77 | */ | |
78 | static zebra_privs_current_t zprivs_null_state = ZPRIVS_RAISED; | |
79 | ||
80 | /* internal privileges state */ | |
81 | static struct _zprivs_t { | |
82 | #ifdef HAVE_CAPABILITIES | |
83 | pstorage_t caps; /* working storage */ | |
84 | pset_t *syscaps_p; /* system-type requested permitted caps */ | |
85 | pset_t *syscaps_i; /* system-type requested inheritable caps */ | |
86 | #endif /* HAVE_CAPABILITIES */ | |
87 | uid_t zuid, /* uid to run as */ | |
88 | zsuid; /* saved uid */ | |
89 | gid_t zgid; /* gid to run as */ | |
90 | gid_t vtygrp; /* gid for vty sockets */ | |
91 | } zprivs_state; | |
92 | ||
93 | /* externally exported but not directly accessed functions */ | |
94 | #ifdef HAVE_CAPABILITIES | |
95 | int zprivs_change_caps(zebra_privs_ops_t); | |
96 | zebra_privs_current_t zprivs_state_caps(void); | |
97 | #endif /* HAVE_CAPABILITIES */ | |
98 | int zprivs_change_uid(zebra_privs_ops_t); | |
99 | zebra_privs_current_t zprivs_state_uid(void); | |
100 | int zprivs_change_null(zebra_privs_ops_t); | |
101 | zebra_privs_current_t zprivs_state_null(void); | |
102 | ||
103 | #ifdef HAVE_CAPABILITIES | |
104 | /* internal capability API */ | |
105 | static pset_t *zcaps2sys(zebra_capabilities_t *, int); | |
106 | static void zprivs_caps_init(struct zebra_privs_t *); | |
107 | static void zprivs_caps_terminate(void); | |
108 | ||
109 | /* Map of Quagga abstract capabilities to system capabilities */ | |
110 | static struct { | |
111 | int num; | |
112 | pvalue_t *system_caps; | |
113 | } cap_map[ZCAP_MAX] = { | |
114 | #ifdef HAVE_LCAPS /* Quagga -> Linux capabilities mappings */ | |
115 | [ZCAP_SETID] = | |
116 | { | |
117 | 2, (pvalue_t[]){CAP_SETGID, CAP_SETUID}, | |
118 | }, | |
119 | [ZCAP_BIND] = | |
120 | { | |
121 | 1, (pvalue_t[]){CAP_NET_BIND_SERVICE}, | |
122 | }, | |
123 | [ZCAP_NET_ADMIN] = | |
124 | { | |
125 | 1, (pvalue_t[]){CAP_NET_ADMIN}, | |
126 | }, | |
127 | [ZCAP_NET_RAW] = | |
128 | { | |
129 | 1, (pvalue_t[]){CAP_NET_RAW}, | |
130 | }, | |
131 | [ZCAP_CHROOT] = | |
132 | { | |
133 | 1, | |
134 | (pvalue_t[]){ | |
135 | CAP_SYS_CHROOT, | |
136 | }, | |
137 | }, | |
138 | [ZCAP_NICE] = | |
139 | { | |
140 | 1, (pvalue_t[]){CAP_SYS_NICE}, | |
141 | }, | |
142 | [ZCAP_PTRACE] = | |
143 | { | |
144 | 1, (pvalue_t[]){CAP_SYS_PTRACE}, | |
145 | }, | |
146 | [ZCAP_DAC_OVERRIDE] = | |
147 | { | |
148 | 1, (pvalue_t[]){CAP_DAC_OVERRIDE}, | |
149 | }, | |
150 | [ZCAP_READ_SEARCH] = | |
151 | { | |
152 | 1, (pvalue_t[]){CAP_DAC_READ_SEARCH}, | |
153 | }, | |
154 | [ZCAP_SYS_ADMIN] = | |
155 | { | |
156 | 1, (pvalue_t[]){CAP_SYS_ADMIN}, | |
157 | }, | |
158 | [ZCAP_FOWNER] = | |
159 | { | |
160 | 1, (pvalue_t[]){CAP_FOWNER}, | |
161 | }, | |
162 | [ZCAP_IPC_LOCK] = | |
163 | { | |
164 | 1, (pvalue_t[]){CAP_IPC_LOCK}, | |
165 | }, | |
166 | #endif /* HAVE_LCAPS */ | |
167 | }; | |
168 | ||
169 | #ifdef HAVE_LCAPS | |
170 | /* Linux forms of capabilities methods */ | |
171 | /* convert zebras privileges to system capabilities */ | |
172 | static pset_t *zcaps2sys(zebra_capabilities_t *zcaps, int num) | |
173 | { | |
174 | pset_t *syscaps; | |
175 | int i, j = 0, count = 0; | |
176 | ||
177 | if (!num) | |
178 | return NULL; | |
179 | ||
180 | /* first count up how many system caps we have */ | |
181 | for (i = 0; i < num; i++) | |
182 | count += cap_map[zcaps[i]].num; | |
183 | ||
184 | if ((syscaps = XCALLOC(MTYPE_PRIVS, (sizeof(pset_t) * num))) == NULL) { | |
185 | fprintf(stderr, "%s: could not allocate syscaps!", __func__); | |
186 | return NULL; | |
187 | } | |
188 | ||
189 | syscaps->caps = XCALLOC(MTYPE_PRIVS, (sizeof(pvalue_t) * count)); | |
190 | ||
191 | if (!syscaps->caps) { | |
192 | fprintf(stderr, "%s: could not XCALLOC caps!", __func__); | |
193 | return NULL; | |
194 | } | |
195 | ||
196 | /* copy the capabilities over */ | |
197 | count = 0; | |
198 | for (i = 0; i < num; i++) | |
199 | for (j = 0; j < cap_map[zcaps[i]].num; j++) | |
200 | syscaps->caps[count++] = | |
201 | cap_map[zcaps[i]].system_caps[j]; | |
202 | ||
203 | /* iterations above should be exact same as previous count, obviously.. | |
204 | */ | |
205 | syscaps->num = count; | |
206 | ||
207 | return syscaps; | |
208 | } | |
209 | ||
210 | /* set or clear the effective capabilities to/from permitted */ | |
211 | int zprivs_change_caps(zebra_privs_ops_t op) | |
212 | { | |
213 | cap_flag_value_t cflag; | |
214 | ||
215 | /* should be no possibility of being called without valid caps */ | |
216 | assert(zprivs_state.syscaps_p && zprivs_state.caps); | |
217 | if (!(zprivs_state.syscaps_p && zprivs_state.caps)) | |
218 | exit(1); | |
219 | ||
220 | if (op == ZPRIVS_RAISE) | |
221 | cflag = CAP_SET; | |
222 | else if (op == ZPRIVS_LOWER) | |
223 | cflag = CAP_CLEAR; | |
224 | else | |
225 | return -1; | |
226 | ||
227 | if (!cap_set_flag(zprivs_state.caps, CAP_EFFECTIVE, | |
228 | zprivs_state.syscaps_p->num, | |
229 | zprivs_state.syscaps_p->caps, cflag)) | |
230 | return cap_set_proc(zprivs_state.caps); | |
231 | return -1; | |
232 | } | |
233 | ||
234 | zebra_privs_current_t zprivs_state_caps(void) | |
235 | { | |
236 | int i; | |
237 | cap_flag_value_t val; | |
238 | ||
239 | /* should be no possibility of being called without valid caps */ | |
240 | assert(zprivs_state.syscaps_p && zprivs_state.caps); | |
241 | if (!(zprivs_state.syscaps_p && zprivs_state.caps)) | |
242 | exit(1); | |
243 | ||
244 | for (i = 0; i < zprivs_state.syscaps_p->num; i++) { | |
245 | if (cap_get_flag(zprivs_state.caps, | |
246 | zprivs_state.syscaps_p->caps[i], CAP_EFFECTIVE, | |
247 | &val)) { | |
248 | flog_err( | |
249 | EC_LIB_SYSTEM_CALL, | |
250 | "zprivs_state_caps: could not cap_get_flag, %s", | |
251 | safe_strerror(errno)); | |
252 | return ZPRIVS_UNKNOWN; | |
253 | } | |
254 | if (val == CAP_SET) | |
255 | return ZPRIVS_RAISED; | |
256 | } | |
257 | return ZPRIVS_LOWERED; | |
258 | } | |
259 | ||
260 | static void zprivs_caps_init(struct zebra_privs_t *zprivs) | |
261 | { | |
262 | zprivs_state.syscaps_p = zcaps2sys(zprivs->caps_p, zprivs->cap_num_p); | |
263 | zprivs_state.syscaps_i = zcaps2sys(zprivs->caps_i, zprivs->cap_num_i); | |
264 | ||
265 | /* Tell kernel we want caps maintained across uid changes */ | |
266 | if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) == -1) { | |
267 | fprintf(stderr, | |
268 | "privs_init: could not set PR_SET_KEEPCAPS, %s\n", | |
269 | safe_strerror(errno)); | |
270 | exit(1); | |
271 | } | |
272 | ||
273 | /* we have caps, we have no need to ever change back the original user | |
274 | */ | |
275 | /* only change uid if we don't have the correct one */ | |
276 | if ((zprivs_state.zuid) && (zprivs_state.zsuid != zprivs_state.zuid)) { | |
277 | if (setreuid(zprivs_state.zuid, zprivs_state.zuid)) { | |
278 | fprintf(stderr, | |
279 | "zprivs_init (cap): could not setreuid, %s\n", | |
280 | safe_strerror(errno)); | |
281 | exit(1); | |
282 | } | |
283 | } | |
284 | ||
285 | if (!zprivs_state.syscaps_p) | |
286 | return; | |
287 | ||
288 | if (!(zprivs_state.caps = cap_init())) { | |
289 | fprintf(stderr, "privs_init: failed to cap_init, %s\n", | |
290 | safe_strerror(errno)); | |
291 | exit(1); | |
292 | } | |
293 | ||
294 | if (cap_clear(zprivs_state.caps)) { | |
295 | fprintf(stderr, "privs_init: failed to cap_clear, %s\n", | |
296 | safe_strerror(errno)); | |
297 | exit(1); | |
298 | } | |
299 | ||
300 | /* set permitted caps */ | |
301 | cap_set_flag(zprivs_state.caps, CAP_PERMITTED, | |
302 | zprivs_state.syscaps_p->num, zprivs_state.syscaps_p->caps, | |
303 | CAP_SET); | |
304 | ||
305 | /* set inheritable caps, if any */ | |
306 | if (zprivs_state.syscaps_i && zprivs_state.syscaps_i->num) { | |
307 | cap_set_flag(zprivs_state.caps, CAP_INHERITABLE, | |
308 | zprivs_state.syscaps_i->num, | |
309 | zprivs_state.syscaps_i->caps, CAP_SET); | |
310 | } | |
311 | ||
312 | /* apply caps. CAP_EFFECTIVE is cleared. we'll raise the caps as | |
313 | * and when, and only when, they are needed. | |
314 | */ | |
315 | if (cap_set_proc(zprivs_state.caps)) { | |
316 | cap_t current_caps; | |
317 | char *current_caps_text = NULL; | |
318 | char *wanted_caps_text = NULL; | |
319 | ||
320 | fprintf(stderr, "privs_init: initial cap_set_proc failed: %s\n", | |
321 | safe_strerror(errno)); | |
322 | ||
323 | current_caps = cap_get_proc(); | |
324 | if (current_caps) { | |
325 | current_caps_text = cap_to_text(current_caps, NULL); | |
326 | cap_free(current_caps); | |
327 | } | |
328 | ||
329 | wanted_caps_text = cap_to_text(zprivs_state.caps, NULL); | |
330 | fprintf(stderr, "Wanted caps: %s\n", | |
331 | wanted_caps_text ? wanted_caps_text : "???"); | |
332 | fprintf(stderr, "Have caps: %s\n", | |
333 | current_caps_text ? current_caps_text : "???"); | |
334 | if (current_caps_text) | |
335 | cap_free(current_caps_text); | |
336 | if (wanted_caps_text) | |
337 | cap_free(wanted_caps_text); | |
338 | ||
339 | exit(1); | |
340 | } | |
341 | ||
342 | /* set methods for the caller to use */ | |
343 | zprivs->change = zprivs_change_caps; | |
344 | zprivs->current_state = zprivs_state_caps; | |
345 | } | |
346 | ||
347 | static void zprivs_caps_terminate(void) | |
348 | { | |
349 | /* Clear all capabilities, if we have any. */ | |
350 | if (zprivs_state.caps) | |
351 | cap_clear(zprivs_state.caps); | |
352 | else | |
353 | return; | |
354 | ||
355 | /* and boom, capabilities are gone forever */ | |
356 | if (cap_set_proc(zprivs_state.caps)) { | |
357 | fprintf(stderr, "privs_terminate: cap_set_proc failed, %s", | |
358 | safe_strerror(errno)); | |
359 | exit(1); | |
360 | } | |
361 | ||
362 | /* free up private state */ | |
363 | if (zprivs_state.syscaps_p->num) { | |
364 | XFREE(MTYPE_PRIVS, zprivs_state.syscaps_p->caps); | |
365 | XFREE(MTYPE_PRIVS, zprivs_state.syscaps_p); | |
366 | } | |
367 | ||
368 | if (zprivs_state.syscaps_i && zprivs_state.syscaps_i->num) { | |
369 | XFREE(MTYPE_PRIVS, zprivs_state.syscaps_i->caps); | |
370 | XFREE(MTYPE_PRIVS, zprivs_state.syscaps_i); | |
371 | } | |
372 | ||
373 | cap_free(zprivs_state.caps); | |
374 | } | |
375 | #else /* !HAVE_LCAPS */ | |
376 | #error "no Linux capabilities, dazed and confused..." | |
377 | #endif /* HAVE_LCAPS */ | |
378 | #endif /* HAVE_CAPABILITIES */ | |
379 | ||
380 | int zprivs_change_uid(zebra_privs_ops_t op) | |
381 | { | |
382 | if (zprivs_state.zsuid == zprivs_state.zuid) | |
383 | return 0; | |
384 | if (op == ZPRIVS_RAISE) | |
385 | return seteuid(zprivs_state.zsuid); | |
386 | else if (op == ZPRIVS_LOWER) | |
387 | return seteuid(zprivs_state.zuid); | |
388 | else | |
389 | return -1; | |
390 | } | |
391 | ||
392 | zebra_privs_current_t zprivs_state_uid(void) | |
393 | { | |
394 | return ((zprivs_state.zuid == geteuid()) ? ZPRIVS_LOWERED | |
395 | : ZPRIVS_RAISED); | |
396 | } | |
397 | ||
398 | int zprivs_change_null(zebra_privs_ops_t op) | |
399 | { | |
400 | return 0; | |
401 | } | |
402 | ||
403 | zebra_privs_current_t zprivs_state_null(void) | |
404 | { | |
405 | return zprivs_null_state; | |
406 | } | |
407 | ||
408 | #ifndef HAVE_GETGROUPLIST | |
409 | /* Solaris 11 has no getgrouplist() */ | |
410 | static int getgrouplist(const char *user, gid_t group, gid_t *groups, | |
411 | int *ngroups) | |
412 | { | |
413 | struct group *grp; | |
414 | size_t usridx; | |
415 | int pos = 0, ret; | |
416 | ||
417 | if (pos < *ngroups) | |
418 | groups[pos] = group; | |
419 | pos++; | |
420 | ||
421 | setgrent(); | |
422 | while ((grp = getgrent())) { | |
423 | if (grp->gr_gid == group) | |
424 | continue; | |
425 | for (usridx = 0; grp->gr_mem[usridx] != NULL; usridx++) | |
426 | if (!strcmp(grp->gr_mem[usridx], user)) { | |
427 | if (pos < *ngroups) | |
428 | groups[pos] = grp->gr_gid; | |
429 | pos++; | |
430 | break; | |
431 | } | |
432 | } | |
433 | endgrent(); | |
434 | ||
435 | ret = (pos <= *ngroups) ? pos : -1; | |
436 | *ngroups = pos; | |
437 | return ret; | |
438 | } | |
439 | #endif /* HAVE_GETGROUPLIST */ | |
440 | ||
441 | /* | |
442 | * Helper function that locates a refcounting object to use: a process-wide | |
443 | * object or a per-pthread object. | |
444 | */ | |
445 | static struct zebra_privs_refs_t *get_privs_refs(struct zebra_privs_t *privs) | |
446 | { | |
447 | struct zebra_privs_refs_t *temp, *refs = NULL; | |
448 | pthread_t tid; | |
449 | ||
450 | if (privs_per_process) | |
451 | refs = &(privs->process_refs); | |
452 | else { | |
453 | /* Locate - or create - the object for the current pthread. */ | |
454 | tid = pthread_self(); | |
455 | ||
456 | STAILQ_FOREACH(temp, &(privs->thread_refs), entry) { | |
457 | if (pthread_equal(temp->tid, tid)) { | |
458 | refs = temp; | |
459 | break; | |
460 | } | |
461 | } | |
462 | ||
463 | /* Need to create a new refcounting object. */ | |
464 | if (refs == NULL) { | |
465 | refs = XCALLOC(MTYPE_PRIVS, | |
466 | sizeof(struct zebra_privs_refs_t)); | |
467 | refs->tid = tid; | |
468 | STAILQ_INSERT_TAIL(&(privs->thread_refs), refs, entry); | |
469 | } | |
470 | } | |
471 | ||
472 | return refs; | |
473 | } | |
474 | ||
475 | struct zebra_privs_t *_zprivs_raise(struct zebra_privs_t *privs, | |
476 | const char *funcname) | |
477 | { | |
478 | int save_errno = errno; | |
479 | struct zebra_privs_refs_t *refs; | |
480 | ||
481 | if (!privs) | |
482 | return NULL; | |
483 | ||
484 | /* | |
485 | * Serialize 'raise' operations; particularly important for | |
486 | * OSes where privs are process-wide. | |
487 | */ | |
488 | frr_with_mutex(&(privs->mutex)) { | |
489 | /* Locate ref-counting object to use */ | |
490 | refs = get_privs_refs(privs); | |
491 | ||
492 | if (++(refs->refcount) == 1) { | |
493 | errno = 0; | |
494 | if (privs->change(ZPRIVS_RAISE)) { | |
495 | zlog_err("%s: Failed to raise privileges (%s)", | |
496 | funcname, safe_strerror(errno)); | |
497 | } | |
498 | errno = save_errno; | |
499 | refs->raised_in_funcname = funcname; | |
500 | } | |
501 | } | |
502 | ||
503 | return privs; | |
504 | } | |
505 | ||
506 | void _zprivs_lower(struct zebra_privs_t **privs) | |
507 | { | |
508 | int save_errno = errno; | |
509 | struct zebra_privs_refs_t *refs; | |
510 | ||
511 | if (!*privs) | |
512 | return; | |
513 | ||
514 | /* Serialize 'lower privs' operation - particularly important | |
515 | * when OS privs are process-wide. | |
516 | */ | |
517 | frr_with_mutex(&(*privs)->mutex) { | |
518 | refs = get_privs_refs(*privs); | |
519 | ||
520 | if (--(refs->refcount) == 0) { | |
521 | errno = 0; | |
522 | if ((*privs)->change(ZPRIVS_LOWER)) { | |
523 | zlog_err("%s: Failed to lower privileges (%s)", | |
524 | refs->raised_in_funcname, | |
525 | safe_strerror(errno)); | |
526 | } | |
527 | errno = save_errno; | |
528 | refs->raised_in_funcname = NULL; | |
529 | } | |
530 | } | |
531 | ||
532 | *privs = NULL; | |
533 | } | |
534 | ||
535 | void zprivs_preinit(struct zebra_privs_t *zprivs) | |
536 | { | |
537 | struct passwd *pwentry = NULL; | |
538 | struct group *grentry = NULL; | |
539 | ||
540 | if (!zprivs) { | |
541 | fprintf(stderr, "zprivs_init: called with NULL arg!\n"); | |
542 | exit(1); | |
543 | } | |
544 | ||
545 | pthread_mutex_init(&(zprivs->mutex), NULL); | |
546 | zprivs->process_refs.refcount = 0; | |
547 | zprivs->process_refs.raised_in_funcname = NULL; | |
548 | STAILQ_INIT(&zprivs->thread_refs); | |
549 | ||
550 | if (zprivs->vty_group) { | |
551 | /* in a "NULL" setup, this is allowed to fail too, but still | |
552 | * try. */ | |
553 | if ((grentry = getgrnam(zprivs->vty_group))) | |
554 | zprivs_state.vtygrp = grentry->gr_gid; | |
555 | else | |
556 | zprivs_state.vtygrp = (gid_t)-1; | |
557 | } | |
558 | ||
559 | /* NULL privs */ | |
560 | if (!(zprivs->user || zprivs->group || zprivs->cap_num_p | |
561 | || zprivs->cap_num_i)) { | |
562 | zprivs->change = zprivs_change_null; | |
563 | zprivs->current_state = zprivs_state_null; | |
564 | return; | |
565 | } | |
566 | ||
567 | if (zprivs->user) { | |
568 | if ((pwentry = getpwnam(zprivs->user)) == NULL) { | |
569 | /* cant use log.h here as it depends on vty */ | |
570 | fprintf(stderr, | |
571 | "privs_init: could not lookup user %s\n", | |
572 | zprivs->user); | |
573 | exit(1); | |
574 | } | |
575 | ||
576 | zprivs_state.zuid = pwentry->pw_uid; | |
577 | zprivs_state.zgid = pwentry->pw_gid; | |
578 | } | |
579 | ||
580 | grentry = NULL; | |
581 | ||
582 | if (zprivs->group) { | |
583 | if ((grentry = getgrnam(zprivs->group)) == NULL) { | |
584 | fprintf(stderr, | |
585 | "privs_init: could not lookup group %s\n", | |
586 | zprivs->group); | |
587 | exit(1); | |
588 | } | |
589 | ||
590 | zprivs_state.zgid = grentry->gr_gid; | |
591 | } | |
592 | } | |
593 | ||
594 | struct zebra_privs_t *lib_privs; | |
595 | ||
596 | void zprivs_init(struct zebra_privs_t *zprivs) | |
597 | { | |
598 | gid_t groups[NGROUPS_MAX] = {}; | |
599 | int i, ngroups = 0; | |
600 | int found = 0; | |
601 | ||
602 | /* NULL privs */ | |
603 | if (!(zprivs->user || zprivs->group || zprivs->cap_num_p | |
604 | || zprivs->cap_num_i)) | |
605 | return; | |
606 | ||
607 | lib_privs = zprivs; | |
608 | ||
609 | if (zprivs->user) { | |
610 | ngroups = array_size(groups); | |
611 | if (getgrouplist(zprivs->user, zprivs_state.zgid, groups, | |
612 | &ngroups) | |
613 | < 0) { | |
614 | /* cant use log.h here as it depends on vty */ | |
615 | fprintf(stderr, | |
616 | "privs_init: could not getgrouplist for user %s\n", | |
617 | zprivs->user); | |
618 | exit(1); | |
619 | } | |
620 | } | |
621 | ||
622 | if (zprivs->vty_group) | |
623 | /* Add the vty_group to the supplementary groups so it can be chowned to | |
624 | */ | |
625 | { | |
626 | if (zprivs_state.vtygrp == (gid_t)-1) { | |
627 | fprintf(stderr, | |
628 | "privs_init: could not lookup vty group %s\n", | |
629 | zprivs->vty_group); | |
630 | exit(1); | |
631 | } | |
632 | ||
633 | for (i = 0; i < ngroups; i++) | |
634 | if (groups[i] == zprivs_state.vtygrp) { | |
635 | found++; | |
636 | break; | |
637 | } | |
638 | ||
639 | if (!found) { | |
640 | fprintf(stderr, | |
641 | "privs_init: user(%s) is not part of vty group specified(%s)\n", | |
642 | zprivs->user, zprivs->vty_group); | |
643 | exit(1); | |
644 | } | |
645 | if (i >= ngroups && ngroups < (int)array_size(groups)) { | |
646 | groups[i] = zprivs_state.vtygrp; | |
647 | } | |
648 | } | |
649 | ||
650 | zprivs_state.zsuid = geteuid(); /* initial uid */ | |
651 | /* add groups only if we changed uid - otherwise skip */ | |
652 | if ((ngroups) && (zprivs_state.zsuid != zprivs_state.zuid)) { | |
653 | if (setgroups(ngroups, groups)) { | |
654 | fprintf(stderr, "privs_init: could not setgroups, %s\n", | |
655 | safe_strerror(errno)); | |
656 | exit(1); | |
657 | } | |
658 | } | |
659 | ||
660 | /* change gid only if we changed uid - otherwise skip */ | |
661 | if ((zprivs_state.zgid) && (zprivs_state.zsuid != zprivs_state.zuid)) { | |
662 | /* change group now, forever. uid we do later */ | |
663 | if (setregid(zprivs_state.zgid, zprivs_state.zgid)) { | |
664 | fprintf(stderr, "zprivs_init: could not setregid, %s\n", | |
665 | safe_strerror(errno)); | |
666 | exit(1); | |
667 | } | |
668 | } | |
669 | ||
670 | #ifdef HAVE_CAPABILITIES | |
671 | zprivs_caps_init(zprivs); | |
672 | ||
673 | /* | |
674 | * If we have initialized the system with no requested | |
675 | * capabilities, change will not have been set | |
676 | * to anything by zprivs_caps_init, As such | |
677 | * we should make sure that when we attempt | |
678 | * to raize privileges that we actually have | |
679 | * a do nothing function to call instead of a | |
680 | * crash :). | |
681 | */ | |
682 | if (!zprivs->change) | |
683 | zprivs->change = zprivs_change_null; | |
684 | ||
685 | #else /* !HAVE_CAPABILITIES */ | |
686 | /* we dont have caps. we'll need to maintain rid and saved uid | |
687 | * and change euid back to saved uid (who we presume has all neccessary | |
688 | * privileges) whenever we are asked to raise our privileges. | |
689 | * | |
690 | * This is not worth that much security wise, but all we can do. | |
691 | */ | |
692 | zprivs_state.zsuid = geteuid(); | |
693 | /* only change uid if we don't have the correct one */ | |
694 | if ((zprivs_state.zuid) && (zprivs_state.zsuid != zprivs_state.zuid)) { | |
695 | if (setreuid(-1, zprivs_state.zuid)) { | |
696 | fprintf(stderr, | |
697 | "privs_init (uid): could not setreuid, %s\n", | |
698 | safe_strerror(errno)); | |
699 | exit(1); | |
700 | } | |
701 | } | |
702 | ||
703 | zprivs->change = zprivs_change_uid; | |
704 | zprivs->current_state = zprivs_state_uid; | |
705 | #endif /* HAVE_CAPABILITIES */ | |
706 | } | |
707 | ||
708 | void zprivs_terminate(struct zebra_privs_t *zprivs) | |
709 | { | |
710 | struct zebra_privs_refs_t *refs; | |
711 | ||
712 | lib_privs = NULL; | |
713 | ||
714 | if (!zprivs) { | |
715 | fprintf(stderr, "%s: no privs struct given, terminating", | |
716 | __func__); | |
717 | exit(0); | |
718 | } | |
719 | ||
720 | #ifdef HAVE_CAPABILITIES | |
721 | if (zprivs->user || zprivs->group || zprivs->cap_num_p | |
722 | || zprivs->cap_num_i) | |
723 | zprivs_caps_terminate(); | |
724 | #else /* !HAVE_CAPABILITIES */ | |
725 | /* only change uid if we don't have the correct one */ | |
726 | if ((zprivs_state.zuid) && (zprivs_state.zsuid != zprivs_state.zuid)) { | |
727 | if (setreuid(zprivs_state.zuid, zprivs_state.zuid)) { | |
728 | fprintf(stderr, | |
729 | "privs_terminate: could not setreuid, %s", | |
730 | safe_strerror(errno)); | |
731 | exit(1); | |
732 | } | |
733 | } | |
734 | #endif /* HAVE_LCAPS */ | |
735 | ||
736 | while ((refs = STAILQ_FIRST(&(zprivs->thread_refs))) != NULL) { | |
737 | STAILQ_REMOVE_HEAD(&(zprivs->thread_refs), entry); | |
738 | XFREE(MTYPE_PRIVS, refs); | |
739 | } | |
740 | ||
741 | zprivs->change = zprivs_change_null; | |
742 | zprivs->current_state = zprivs_state_null; | |
743 | zprivs_null_state = ZPRIVS_LOWERED; | |
744 | return; | |
745 | } | |
746 | ||
747 | void zprivs_get_ids(struct zprivs_ids_t *ids) | |
748 | { | |
749 | ||
750 | ids->uid_priv = getuid(); | |
751 | (zprivs_state.zuid) ? (ids->uid_normal = zprivs_state.zuid) | |
752 | : (ids->uid_normal = (uid_t)-1); | |
753 | (zprivs_state.zgid) ? (ids->gid_normal = zprivs_state.zgid) | |
754 | : (ids->gid_normal = (uid_t)-1); | |
755 | (zprivs_state.vtygrp) ? (ids->gid_vty = zprivs_state.vtygrp) | |
756 | : (ids->gid_vty = (uid_t)-1); | |
757 | ||
758 | return; | |
759 | } |