1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2013 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
25 #include "conf-files.h"
26 #include "bus-internal.h"
27 #include "bus-message.h"
28 #include "bus-policy.h"
30 static void policy_item_free(PolicyItem *i) {
41 DEFINE_TRIVIAL_CLEANUP_FUNC(PolicyItem*, policy_item_free);
43 static void item_append(PolicyItem *i, PolicyItem **list) {
47 LIST_FIND_TAIL(items, *list, tail);
48 LIST_INSERT_AFTER(items, *list, tail, i);
51 static int file_load(Policy *p, const char *path) {
53 _cleanup_free_ char *c = NULL, *policy_user = NULL, *policy_group = NULL;
54 _cleanup_(policy_item_freep) PolicyItem *i = NULL;
55 void *xml_state = NULL;
67 STATE_POLICY_OTHER_ATTRIBUTE,
69 STATE_ALLOW_DENY_INTERFACE,
70 STATE_ALLOW_DENY_MEMBER,
71 STATE_ALLOW_DENY_ERROR,
72 STATE_ALLOW_DENY_PATH,
73 STATE_ALLOW_DENY_MESSAGE_TYPE,
74 STATE_ALLOW_DENY_NAME,
75 STATE_ALLOW_DENY_OTHER_ATTRIBUTE,
77 } state = STATE_OUTSIDE;
81 POLICY_CATEGORY_DEFAULT,
82 POLICY_CATEGORY_MANDATORY,
85 } policy_category = POLICY_CATEGORY_NONE;
91 r = read_full_file(path, &c, NULL);
98 log_error("Failed to load %s: %s", path, strerror(-r));
104 _cleanup_free_ char *name = NULL;
107 t = xml_tokenize(&q, &name, &xml_state, &line);
109 log_error("XML parse failure in %s: %s", path, strerror(-t));
117 if (t == XML_TAG_OPEN) {
118 if (streq(name, "busconfig"))
119 state = STATE_BUSCONFIG;
121 log_error("Unexpected tag %s at %s:%u.", name, path, line);
125 } else if (t == XML_END)
127 else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
128 log_error("Unexpected token (1) at %s:%u.", path, line);
134 case STATE_BUSCONFIG:
136 if (t == XML_TAG_OPEN) {
137 if (streq(name, "policy")) {
138 state = STATE_POLICY;
139 policy_category = POLICY_CATEGORY_NONE;
142 policy_user = policy_group = NULL;
147 } else if (t == XML_TAG_CLOSE_EMPTY ||
148 (t == XML_TAG_CLOSE && streq(name, "busconfig")))
149 state = STATE_OUTSIDE;
150 else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
151 log_error("Unexpected token (2) at %s:%u.", path, line);
159 if (t == XML_ATTRIBUTE_NAME) {
160 if (streq(name, "context"))
161 state = STATE_POLICY_CONTEXT;
162 else if (streq(name, "user"))
163 state = STATE_POLICY_USER;
164 else if (streq(name, "group"))
165 state = STATE_POLICY_GROUP;
167 if (streq(name, "at_console"))
168 log_debug("Attribute %s of <policy> tag unsupported at %s:%u, ignoring.", name, path, line);
170 log_warning("Attribute %s of <policy> tag unknown at %s:%u, ignoring.", name, path, line);
171 state = STATE_POLICY_OTHER_ATTRIBUTE;
173 } else if (t == XML_TAG_CLOSE_EMPTY ||
174 (t == XML_TAG_CLOSE && streq(name, "policy")))
175 state = STATE_BUSCONFIG;
176 else if (t == XML_TAG_OPEN) {
179 if (streq(name, "allow"))
180 it = POLICY_ITEM_ALLOW;
181 else if (streq(name, "deny"))
182 it = POLICY_ITEM_DENY;
184 log_warning("Unknown tag %s in <policy> %s:%u.", name, path, line);
189 i = new0(PolicyItem, 1);
194 state = STATE_ALLOW_DENY;
196 } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
197 log_error("Unexpected token (3) at %s:%u.", path, line);
203 case STATE_POLICY_CONTEXT:
205 if (t == XML_ATTRIBUTE_VALUE) {
206 if (streq(name, "default")) {
207 policy_category = POLICY_CATEGORY_DEFAULT;
208 state = STATE_POLICY;
209 } else if (streq(name, "mandatory")) {
210 policy_category = POLICY_CATEGORY_MANDATORY;
211 state = STATE_POLICY;
213 log_error("context= parameter %s unknown for <policy> at %s:%u.", name, path, line);
217 log_error("Unexpected token (4) at %s:%u.", path, line);
223 case STATE_POLICY_USER:
225 if (t == XML_ATTRIBUTE_VALUE) {
229 policy_category = POLICY_CATEGORY_USER;
230 state = STATE_POLICY;
232 log_error("Unexpected token (5) in %s:%u.", path, line);
238 case STATE_POLICY_GROUP:
240 if (t == XML_ATTRIBUTE_VALUE) {
244 policy_category = POLICY_CATEGORY_GROUP;
245 state = STATE_POLICY;
247 log_error("Unexpected token (6) at %s:%u.", path, line);
253 case STATE_POLICY_OTHER_ATTRIBUTE:
255 if (t == XML_ATTRIBUTE_VALUE)
256 state = STATE_POLICY;
258 log_error("Unexpected token (7) in %s:%u.", path, line);
264 case STATE_ALLOW_DENY:
268 if (t == XML_ATTRIBUTE_NAME) {
271 if (startswith(name, "send_"))
272 ic = POLICY_ITEM_SEND;
273 else if (startswith(name, "receive_"))
274 ic = POLICY_ITEM_RECV;
275 else if (streq(name, "own"))
276 ic = POLICY_ITEM_OWN;
277 else if (streq(name, "own_prefix"))
278 ic = POLICY_ITEM_OWN_PREFIX;
279 else if (streq(name, "user"))
280 ic = POLICY_ITEM_USER;
281 else if (streq(name, "group"))
282 ic = POLICY_ITEM_GROUP;
283 else if (streq(name, "eavesdrop")) {
284 log_debug("Unsupported attribute %s= at %s:%u, ignoring.", name, path, line);
285 i->class = POLICY_ITEM_IGNORE;
286 state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
289 log_error("Unknown attribute %s= at %s:%u, ignoring.", name, path, line);
290 state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
294 if (i->class != _POLICY_ITEM_CLASS_UNSET && ic != i->class) {
295 log_error("send_ and receive_ fields mixed on same tag at %s:%u.", path, line);
301 if (ic == POLICY_ITEM_SEND || ic == POLICY_ITEM_RECV) {
304 u = strchr(name, '_');
309 if (streq(u, "interface"))
310 state = STATE_ALLOW_DENY_INTERFACE;
311 else if (streq(u, "member"))
312 state = STATE_ALLOW_DENY_MEMBER;
313 else if (streq(u, "error"))
314 state = STATE_ALLOW_DENY_ERROR;
315 else if (streq(u, "path"))
316 state = STATE_ALLOW_DENY_PATH;
317 else if (streq(u, "type"))
318 state = STATE_ALLOW_DENY_MESSAGE_TYPE;
319 else if ((streq(u, "destination") && ic == POLICY_ITEM_SEND) ||
320 (streq(u, "sender") && ic == POLICY_ITEM_RECV))
321 state = STATE_ALLOW_DENY_NAME;
323 if (streq(u, "requested_reply"))
324 log_debug("Unsupported attribute %s= at %s:%u, ignoring.", name, path, line);
326 log_error("Unknown attribute %s= at %s:%u, ignoring.", name, path, line);
327 state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
331 state = STATE_ALLOW_DENY_NAME;
333 } else if (t == XML_TAG_CLOSE_EMPTY ||
334 (t == XML_TAG_CLOSE && streq(name, i->type == POLICY_ITEM_ALLOW ? "allow" : "deny"))) {
336 if (i->class == _POLICY_ITEM_CLASS_UNSET) {
337 log_error("Policy not set at %s:%u.", path, line);
341 if (policy_category == POLICY_CATEGORY_DEFAULT)
342 item_append(i, &p->default_items);
343 else if (policy_category == POLICY_CATEGORY_MANDATORY)
344 item_append(i, &p->mandatory_items);
345 else if (policy_category == POLICY_CATEGORY_USER) {
346 const char *u = policy_user;
348 assert_cc(sizeof(uid_t) == sizeof(uint32_t));
350 r = hashmap_ensure_allocated(&p->user_items, NULL);
355 log_error("User policy without name");
359 r = get_user_creds(&u, &i->uid, NULL, NULL, NULL);
361 log_error("Failed to resolve user %s, ignoring policy: %s", u, strerror(-r));
366 first = hashmap_get(p->user_items, UINT32_TO_PTR(i->uid));
367 item_append(i, &first);
370 r = hashmap_replace(p->user_items, UINT32_TO_PTR(i->uid), first);
372 LIST_REMOVE(items, first, i);
377 } else if (policy_category == POLICY_CATEGORY_GROUP) {
378 const char *g = policy_group;
380 assert_cc(sizeof(gid_t) == sizeof(uint32_t));
382 r = hashmap_ensure_allocated(&p->group_items, NULL);
387 log_error("Group policy without name");
391 r = get_group_creds(&g, &i->gid);
393 log_error("Failed to resolve group %s, ignoring policy: %s", g, strerror(-r));
398 first = hashmap_get(p->group_items, UINT32_TO_PTR(i->gid));
399 item_append(i, &first);
402 r = hashmap_replace(p->group_items, UINT32_TO_PTR(i->gid), first);
404 LIST_REMOVE(items, first, i);
410 state = STATE_POLICY;
413 } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
414 log_error("Unexpected token (8) at %s:%u.", path, line);
420 case STATE_ALLOW_DENY_INTERFACE:
422 if (t == XML_ATTRIBUTE_VALUE) {
425 log_error("Duplicate interface at %s:%u.", path, line);
431 state = STATE_ALLOW_DENY;
433 log_error("Unexpected token (9) at %s:%u.", path, line);
439 case STATE_ALLOW_DENY_MEMBER:
441 if (t == XML_ATTRIBUTE_VALUE) {
444 log_error("Duplicate member in %s:%u.", path, line);
450 state = STATE_ALLOW_DENY;
452 log_error("Unexpected token (10) in %s:%u.", path, line);
458 case STATE_ALLOW_DENY_ERROR:
460 if (t == XML_ATTRIBUTE_VALUE) {
463 log_error("Duplicate error in %s:%u.", path, line);
469 state = STATE_ALLOW_DENY;
471 log_error("Unexpected token (11) in %s:%u.", path, line);
477 case STATE_ALLOW_DENY_PATH:
479 if (t == XML_ATTRIBUTE_VALUE) {
482 log_error("Duplicate path in %s:%u.", path, line);
488 state = STATE_ALLOW_DENY;
490 log_error("Unexpected token (12) in %s:%u.", path, line);
496 case STATE_ALLOW_DENY_MESSAGE_TYPE:
498 if (t == XML_ATTRIBUTE_VALUE) {
501 if (i->message_type != 0) {
502 log_error("Duplicate message type in %s:%u.", path, line);
506 r = bus_message_type_from_string(name, &i->message_type);
508 log_error("Invalid message type in %s:%u.", path, line);
512 state = STATE_ALLOW_DENY;
514 log_error("Unexpected token (13) in %s:%u.", path, line);
520 case STATE_ALLOW_DENY_NAME:
522 if (t == XML_ATTRIBUTE_VALUE) {
525 log_error("Duplicate name in %s:%u.", path, line);
530 case POLICY_ITEM_USER:
531 if (!streq(name, "*")) {
532 const char *u = name;
534 r = get_user_creds(&u, &i->uid, NULL, NULL, NULL);
536 log_error("Failed to resolve user %s: %s", name, strerror(-r));
541 case POLICY_ITEM_GROUP:
542 if (!streq(name, "*")) {
543 const char *g = name;
545 r = get_group_creds(&g, &i->gid);
547 log_error("Failed to resolve group %s: %s", name, strerror(-r));
559 state = STATE_ALLOW_DENY;
561 log_error("Unexpected token (14) in %s:%u.", path, line);
567 case STATE_ALLOW_DENY_OTHER_ATTRIBUTE:
569 if (t == XML_ATTRIBUTE_VALUE)
570 state = STATE_ALLOW_DENY;
572 log_error("Unexpected token (15) in %s:%u.", path, line);
580 if (t == XML_TAG_OPEN)
582 else if (t == XML_TAG_CLOSE || t == XML_TAG_CLOSE_EMPTY) {
585 state = STATE_BUSCONFIG;
601 struct policy_check_filter {
602 PolicyItemClass class;
603 const struct ucred *ucred;
606 const char *interface;
611 static int is_permissive(PolicyItem *i) {
615 return (i->type == POLICY_ITEM_ALLOW) ? ALLOW : DENY;
618 static int check_policy_item(PolicyItem *i, const struct policy_check_filter *filter) {
624 case POLICY_ITEM_SEND:
625 case POLICY_ITEM_RECV:
627 if (i->name && !streq_ptr(i->name, filter->name))
630 if ((i->message_type != 0) && (i->message_type != filter->message_type))
633 if (i->path && !streq_ptr(i->path, filter->path))
636 if (i->member && !streq_ptr(i->member, filter->member))
639 if (i->interface && !streq_ptr(i->interface, filter->interface))
642 return is_permissive(i);
644 case POLICY_ITEM_OWN:
645 assert(filter->name);
647 if (streq(i->name, "*") || streq(i->name, filter->name))
648 return is_permissive(i);
651 case POLICY_ITEM_OWN_PREFIX:
652 assert(filter->name);
654 if (streq(i->name, "*") || service_name_startswith(filter->name, i->name))
655 return is_permissive(i);
658 case POLICY_ITEM_USER:
659 assert(filter->ucred);
661 if ((streq_ptr(i->name, "*") || (i->uid_valid && i->uid == filter->ucred->uid)))
662 return is_permissive(i);
665 case POLICY_ITEM_GROUP:
666 assert(filter->ucred);
668 if ((streq_ptr(i->name, "*") || (i->gid_valid && i->gid == filter->ucred->gid)))
669 return is_permissive(i);
672 case POLICY_ITEM_IGNORE:
680 static int check_policy_items(PolicyItem *items, const struct policy_check_filter *filter) {
687 /* Check all policies in a set - a broader one might be followed by a more specific one,
688 * and the order of rules in policy definitions matters */
689 LIST_FOREACH(items, i, items) {
690 if (i->class != filter->class &&
691 !(i->class == POLICY_ITEM_OWN_PREFIX && filter->class == POLICY_ITEM_OWN))
694 r = check_policy_item(i, filter);
702 static int policy_check(Policy *p, const struct policy_check_filter *filter) {
710 assert(IN_SET(filter->class, POLICY_ITEM_SEND, POLICY_ITEM_RECV, POLICY_ITEM_OWN, POLICY_ITEM_USER, POLICY_ITEM_GROUP));
713 * The policy check is implemented by the following logic:
715 * 1. Check mandatory items. If the message matches any of these, it is decisive.
716 * 2. See if the passed ucred match against the user/group hashmaps. A matching entry is also decisive.
717 * 3. Consult the defaults if non of the above matched with a more specific rule.
718 * 4. If the message isn't caught be the defaults either, reject it.
721 r = check_policy_items(p->mandatory_items, filter);
726 items = hashmap_get(p->user_items, UINT32_TO_PTR(filter->ucred->uid));
728 r = check_policy_items(items, filter);
733 items = hashmap_get(p->group_items, UINT32_TO_PTR(filter->ucred->gid));
735 r = check_policy_items(items, filter);
741 return check_policy_items(p->default_items, filter);
744 bool policy_check_own(Policy *p, const struct ucred *ucred, const char *name) {
746 struct policy_check_filter filter = {
747 .class = POLICY_ITEM_OWN,
752 return policy_check(p, &filter) == ALLOW;
755 bool policy_check_hello(Policy *p, const struct ucred *ucred) {
757 struct policy_check_filter filter = {
762 filter.class = POLICY_ITEM_USER;
763 user = policy_check(p, &filter);
767 filter.class = POLICY_ITEM_GROUP;
768 group = policy_check(p, &filter);
772 return !(user == DUNNO && group == DUNNO);
775 bool policy_check_recv(Policy *p,
776 const struct ucred *ucred,
780 const char *interface,
781 const char *member) {
783 struct policy_check_filter filter = {
784 .class = POLICY_ITEM_RECV,
786 .message_type = message_type,
788 .interface = interface,
793 return policy_check(p, &filter) == ALLOW;
796 bool policy_check_send(Policy *p,
797 const struct ucred *ucred,
801 const char *interface,
802 const char *member) {
804 struct policy_check_filter filter = {
805 .class = POLICY_ITEM_SEND,
807 .message_type = message_type,
809 .interface = interface,
814 return policy_check(p, &filter) == ALLOW;
817 int policy_load(Policy *p, char **files) {
823 STRV_FOREACH(i, files) {
825 r = file_load(p, *i);
827 _cleanup_strv_free_ char **l = NULL;
830 r = conf_files_list(&l, ".conf", NULL, *i, NULL);
832 log_error("Failed to get configuration file list: %s", strerror(-r));
840 /* We ignore all errors but EISDIR, and just proceed. */
846 void policy_free(Policy *p) {
847 PolicyItem *i, *first;
852 while ((i = p->default_items)) {
853 LIST_REMOVE(items, p->default_items, i);
857 while ((i = p->mandatory_items)) {
858 LIST_REMOVE(items, p->mandatory_items, i);
862 while ((first = hashmap_steal_first(p->user_items))) {
864 while ((i = first)) {
865 LIST_REMOVE(items, first, i);
870 while ((first = hashmap_steal_first(p->group_items))) {
872 while ((i = first)) {
873 LIST_REMOVE(items, first, i);
878 hashmap_free(p->user_items);
879 hashmap_free(p->group_items);
881 p->user_items = p->group_items = NULL;
884 static void dump_items(PolicyItem *items, const char *prefix) {
894 LIST_FOREACH(items, i, items) {
896 printf("%sType: %s\n"
898 prefix, policy_item_type_to_string(i->type),
899 prefix, policy_item_class_to_string(i->class));
902 printf("%sInterface: %s\n",
903 prefix, i->interface);
906 printf("%sMember: %s\n",
910 printf("%sError: %s\n",
914 printf("%sPath: %s\n",
918 printf("%sName: %s\n",
921 if (i->message_type != 0)
922 printf("%sMessage Type: %s\n",
923 prefix, bus_message_type_to_string(i->message_type));
926 _cleanup_free_ char *user;
928 user = uid_to_name(i->uid);
930 printf("%sUser: %s (%d)\n",
931 prefix, strna(user), i->uid);
935 _cleanup_free_ char *group;
937 group = gid_to_name(i->gid);
939 printf("%sGroup: %s (%d)\n",
940 prefix, strna(group), i->gid);
945 static void dump_hashmap_items(Hashmap *h) {
950 HASHMAP_FOREACH_KEY(i, k, h, j) {
951 printf("\t%s Item for %u:\n", draw_special_char(DRAW_ARROW), PTR_TO_UINT(k));
952 dump_items(i, "\t\t");
956 void policy_dump(Policy *p) {
958 printf("%s Default Items:\n", draw_special_char(DRAW_ARROW));
959 dump_items(p->default_items, "\t");
961 printf("%s Group Items:\n", draw_special_char(DRAW_ARROW));
962 dump_hashmap_items(p->group_items);
964 printf("%s User Items:\n", draw_special_char(DRAW_ARROW));
965 dump_hashmap_items(p->user_items);
967 printf("%s Mandatory Items:\n", draw_special_char(DRAW_ARROW));
968 dump_items(p->mandatory_items, "\t");
971 static const char* const policy_item_type_table[_POLICY_ITEM_TYPE_MAX] = {
972 [_POLICY_ITEM_TYPE_UNSET] = "unset",
973 [POLICY_ITEM_ALLOW] = "allow",
974 [POLICY_ITEM_DENY] = "deny",
976 DEFINE_STRING_TABLE_LOOKUP(policy_item_type, PolicyItemType);
978 static const char* const policy_item_class_table[_POLICY_ITEM_CLASS_MAX] = {
979 [_POLICY_ITEM_CLASS_UNSET] = "unset",
980 [POLICY_ITEM_SEND] = "send",
981 [POLICY_ITEM_RECV] = "recv",
982 [POLICY_ITEM_OWN] = "own",
983 [POLICY_ITEM_OWN_PREFIX] = "own-prefix",
984 [POLICY_ITEM_USER] = "user",
985 [POLICY_ITEM_GROUP] = "group",
986 [POLICY_ITEM_IGNORE] = "ignore",
988 DEFINE_STRING_TABLE_LOOKUP(policy_item_class, PolicyItemClass);