1 /* Authors: Joshua Brindle <jbrindle@tresys.com>
2 *
3 * Assertion checker for avtab entries, taken from
4 * checkpolicy.c by Stephen Smalley <sds@tycho.nsa.gov>
5 *
6 * Copyright (C) 2005 Tresys Technology, LLC
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but 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.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <sepol/policydb/avtab.h>
24 #include <sepol/policydb/policydb.h>
25 #include <sepol/policydb/expand.h>
26 #include <sepol/policydb/util.h>
27
28 #include "debug.h"
29
report_failure(sepol_handle_t * handle,policydb_t * p,const avrule_t * avrule,unsigned int stype,unsigned int ttype,const class_perm_node_t * curperm,const avtab_ptr_t node)30 static void report_failure(sepol_handle_t *handle, policydb_t *p,
31 const avrule_t * avrule,
32 unsigned int stype, unsigned int ttype,
33 const class_perm_node_t *curperm,
34 const avtab_ptr_t node)
35 {
36 if (avrule->source_filename) {
37 ERR(handle, "neverallow on line %lu of %s (or line %lu of policy.conf) violated by allow %s %s:%s {%s };",
38 avrule->source_line, avrule->source_filename, avrule->line,
39 p->p_type_val_to_name[stype],
40 p->p_type_val_to_name[ttype],
41 p->p_class_val_to_name[curperm->tclass - 1],
42 sepol_av_to_string(p, curperm->tclass,
43 node->datum.data & curperm->data));
44 } else if (avrule->line) {
45 ERR(handle, "neverallow on line %lu violated by allow %s %s:%s {%s };",
46 avrule->line, p->p_type_val_to_name[stype],
47 p->p_type_val_to_name[ttype],
48 p->p_class_val_to_name[curperm->tclass - 1],
49 sepol_av_to_string(p, curperm->tclass,
50 node->datum.data & curperm->data));
51 } else {
52 ERR(handle, "neverallow violated by allow %s %s:%s {%s };",
53 p->p_type_val_to_name[stype],
54 p->p_type_val_to_name[ttype],
55 p->p_class_val_to_name[curperm->tclass - 1],
56 sepol_av_to_string(p, curperm->tclass,
57 node->datum.data & curperm->data));
58 }
59 }
60
check_assertion_helper(sepol_handle_t * handle,policydb_t * p,avtab_t * te_avtab,avtab_t * te_cond_avtab,unsigned int stype,unsigned int ttype,const avrule_t * avrule)61 static unsigned long check_assertion_helper(sepol_handle_t * handle,
62 policydb_t * p,
63 avtab_t * te_avtab, avtab_t * te_cond_avtab,
64 unsigned int stype, unsigned int ttype,
65 const avrule_t * avrule)
66 {
67 avtab_key_t avkey;
68 avtab_ptr_t node;
69 class_perm_node_t *curperm;
70 unsigned long errors = 0;
71
72 for (curperm = avrule->perms; curperm != NULL; curperm = curperm->next) {
73 avkey.source_type = stype + 1;
74 avkey.target_type = ttype + 1;
75 avkey.target_class = curperm->tclass;
76 avkey.specified = AVTAB_ALLOWED;
77 for (node = avtab_search_node(te_avtab, &avkey);
78 node != NULL;
79 node = avtab_search_node_next(node, avkey.specified)) {
80 if (node->datum.data & curperm->data) {
81 report_failure(handle, p, avrule, stype, ttype, curperm, node);
82 errors++;
83 }
84 }
85 for (node = avtab_search_node(te_cond_avtab, &avkey);
86 node != NULL;
87 node = avtab_search_node_next(node, avkey.specified)) {
88 if (node->datum.data & curperm->data) {
89 report_failure(handle, p, avrule, stype, ttype, curperm, node);
90 errors++;
91 }
92 }
93 }
94
95 return errors;
96 }
97
check_assertions(sepol_handle_t * handle,policydb_t * p,avrule_t * avrules)98 int check_assertions(sepol_handle_t * handle, policydb_t * p,
99 avrule_t * avrules)
100 {
101 avrule_t *a;
102 avtab_t te_avtab, te_cond_avtab;
103 ebitmap_node_t *snode, *tnode;
104 unsigned int i, j;
105 unsigned long errors = 0;
106
107 if (!avrules) {
108 /* Since assertions are stored in avrules, if it is NULL
109 there won't be any to check. This also prevents an invalid
110 free if the avtabs are never initialized */
111 return 0;
112 }
113
114 if (avrules) {
115 if (avtab_init(&te_avtab))
116 goto oom;
117 if (avtab_init(&te_cond_avtab)) {
118 avtab_destroy(&te_avtab);
119 goto oom;
120 }
121 if (expand_avtab(p, &p->te_avtab, &te_avtab) ||
122 expand_avtab(p, &p->te_cond_avtab, &te_cond_avtab)) {
123 avtab_destroy(&te_avtab);
124 avtab_destroy(&te_cond_avtab);
125 goto oom;
126 }
127 }
128
129 for (a = avrules; a != NULL; a = a->next) {
130 ebitmap_t *stypes = &a->stypes.types;
131 ebitmap_t *ttypes = &a->ttypes.types;
132
133 if (!(a->specified & AVRULE_NEVERALLOW))
134 continue;
135
136 ebitmap_for_each_bit(stypes, snode, i) {
137 if (!ebitmap_node_get_bit(snode, i))
138 continue;
139 if (a->flags & RULE_SELF) {
140 errors += check_assertion_helper
141 (handle, p, &te_avtab, &te_cond_avtab, i, i,
142 a);
143 }
144 ebitmap_for_each_bit(ttypes, tnode, j) {
145 if (!ebitmap_node_get_bit(tnode, j))
146 continue;
147 errors += check_assertion_helper
148 (handle, p, &te_avtab, &te_cond_avtab, i, j,
149 a);
150 }
151 }
152 }
153
154 if (errors)
155 ERR(handle, "%lu neverallow failures occurred", errors);
156
157 avtab_destroy(&te_avtab);
158 avtab_destroy(&te_cond_avtab);
159 return errors ? -1 : 0;
160
161 oom:
162 ERR(handle, "Out of memory - unable to check neverallows");
163 return -1;
164 }
165