1 /*
2 * AppArmor security module
3 *
4 * This file contains AppArmor file mediation function definitions.
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2010 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 */
14
15 #ifndef __AA_FILE_H
16 #define __AA_FILE_H
17
18 #include "domain.h"
19 #include "match.h"
20
21 struct aa_profile;
22 struct path;
23
24 /*
25 * We use MAY_EXEC, MAY_WRITE, MAY_READ, MAY_APPEND and the following flags
26 * for profile permissions
27 */
28 #define AA_MAY_CREATE 0x0010
29 #define AA_MAY_DELETE 0x0020
30 #define AA_MAY_META_WRITE 0x0040
31 #define AA_MAY_META_READ 0x0080
32
33 #define AA_MAY_CHMOD 0x0100
34 #define AA_MAY_CHOWN 0x0200
35 #define AA_MAY_LOCK 0x0400
36 #define AA_EXEC_MMAP 0x0800
37
38 #define AA_MAY_LINK 0x1000
39 #define AA_LINK_SUBSET AA_MAY_LOCK /* overlaid */
40 #define AA_MAY_ONEXEC 0x40000000 /* exec allows onexec */
41 #define AA_MAY_CHANGE_PROFILE 0x80000000
42 #define AA_MAY_CHANGEHAT 0x80000000 /* ctrl auditing only */
43
44 #define AA_AUDIT_FILE_MASK (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
45 AA_MAY_CREATE | AA_MAY_DELETE | \
46 AA_MAY_META_READ | AA_MAY_META_WRITE | \
47 AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
48 AA_EXEC_MMAP | AA_MAY_LINK)
49
50 /*
51 * The xindex is broken into 3 parts
52 * - index - an index into either the exec name table or the variable table
53 * - exec type - which determines how the executable name and index are used
54 * - flags - which modify how the destination name is applied
55 */
56 #define AA_X_INDEX_MASK 0x03ff
57
58 #define AA_X_TYPE_MASK 0x0c00
59 #define AA_X_TYPE_SHIFT 10
60 #define AA_X_NONE 0x0000
61 #define AA_X_NAME 0x0400 /* use executable name px */
62 #define AA_X_TABLE 0x0800 /* use a specified name ->n# */
63
64 #define AA_X_UNSAFE 0x1000
65 #define AA_X_CHILD 0x2000 /* make >AA_X_NONE apply to children */
66 #define AA_X_INHERIT 0x4000
67 #define AA_X_UNCONFINED 0x8000
68
69 /* AA_SECURE_X_NEEDED - is passed in the bprm->unsafe field */
70 #define AA_SECURE_X_NEEDED 0x8000
71
72 /* need to make conditional which ones are being set */
73 struct path_cond {
74 uid_t uid;
75 umode_t mode;
76 };
77
78 /* struct file_perms - file permission
79 * @allow: mask of permissions that are allowed
80 * @audit: mask of permissions to force an audit message for
81 * @quiet: mask of permissions to quiet audit messages for
82 * @kill: mask of permissions that when matched will kill the task
83 * @xindex: exec transition index if @allow contains MAY_EXEC
84 *
85 * The @audit and @queit mask should be mutually exclusive.
86 */
87 struct file_perms {
88 u32 allow;
89 u32 audit;
90 u32 quiet;
91 u32 kill;
92 u16 xindex;
93 };
94
95 extern struct file_perms nullperms;
96
97 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
98
99 /* FIXME: split perms from dfa and match this to description
100 * also add delegation info.
101 */
dfa_map_xindex(u16 mask)102 static inline u16 dfa_map_xindex(u16 mask)
103 {
104 u16 old_index = (mask >> 10) & 0xf;
105 u16 index = 0;
106
107 if (mask & 0x100)
108 index |= AA_X_UNSAFE;
109 if (mask & 0x200)
110 index |= AA_X_INHERIT;
111 if (mask & 0x80)
112 index |= AA_X_UNCONFINED;
113
114 if (old_index == 1) {
115 index |= AA_X_UNCONFINED;
116 } else if (old_index == 2) {
117 index |= AA_X_NAME;
118 } else if (old_index == 3) {
119 index |= AA_X_NAME | AA_X_CHILD;
120 } else if (old_index) {
121 index |= AA_X_TABLE;
122 index |= old_index - 4;
123 }
124
125 return index;
126 }
127
128 /*
129 * map old dfa inline permissions to new format
130 */
131 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
132 ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
133 #define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
134 #define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
135 #define dfa_user_xindex(dfa, state) \
136 (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
137
138 #define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
139 0x7f) | \
140 ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
141 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
142 #define dfa_other_quiet(dfa, state) \
143 ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
144 #define dfa_other_xindex(dfa, state) \
145 dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
146
147 int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
148 gfp_t gfp, int op, u32 request, const char *name,
149 const char *target, uid_t ouid, const char *info, int error);
150
151 /**
152 * struct aa_file_rules - components used for file rule permissions
153 * @dfa: dfa to match path names and conditionals against
154 * @perms: permission table indexed by the matched state accept entry of @dfa
155 * @trans: transition table for indexed by named x transitions
156 *
157 * File permission are determined by matching a path against @dfa and then
158 * then using the value of the accept entry for the matching state as
159 * an index into @perms. If a named exec transition is required it is
160 * looked up in the transition table.
161 */
162 struct aa_file_rules {
163 unsigned int start;
164 struct aa_dfa *dfa;
165 /* struct perms perms; */
166 struct aa_domain trans;
167 /* TODO: add delegate table */
168 };
169
170 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
171 const char *name, struct path_cond *cond,
172 struct file_perms *perms);
173
174 int aa_path_perm(int op, struct aa_profile *profile, struct path *path,
175 int flags, u32 request, struct path_cond *cond);
176
177 int aa_path_link(struct aa_profile *profile, struct dentry *old_dentry,
178 struct path *new_dir, struct dentry *new_dentry);
179
180 int aa_file_perm(int op, struct aa_profile *profile, struct file *file,
181 u32 request);
182
aa_free_file_rules(struct aa_file_rules * rules)183 static inline void aa_free_file_rules(struct aa_file_rules *rules)
184 {
185 aa_put_dfa(rules->dfa);
186 aa_free_domain_entries(&rules->trans);
187 }
188
189 #define ACC_FMODE(x) (("\000\004\002\006"[(x)&O_ACCMODE]) | (((x) << 1) & 0x40))
190
191 /* from namei.c */
192 #define MAP_OPEN_FLAGS(x) ((((x) + 1) & O_ACCMODE) ? (x) + 1 : (x))
193
194 /**
195 * aa_map_file_perms - map file flags to AppArmor permissions
196 * @file: open file to map flags to AppArmor permissions
197 *
198 * Returns: apparmor permission set for the file
199 */
aa_map_file_to_perms(struct file * file)200 static inline u32 aa_map_file_to_perms(struct file *file)
201 {
202 int flags = MAP_OPEN_FLAGS(file->f_flags);
203 u32 perms = ACC_FMODE(file->f_mode);
204
205 if ((flags & O_APPEND) && (perms & MAY_WRITE))
206 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
207 /* trunc implies write permission */
208 if (flags & O_TRUNC)
209 perms |= MAY_WRITE;
210 if (flags & O_CREAT)
211 perms |= AA_MAY_CREATE;
212
213 return perms;
214 }
215
216 #endif /* __AA_FILE_H */
217