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 <linux/spinlock.h>
19
20 #include "domain.h"
21 #include "match.h"
22 #include "perms.h"
23
24 struct aa_profile;
25 struct path;
26
27 #define mask_mode_t(X) (X & (MAY_EXEC | MAY_WRITE | MAY_READ | MAY_APPEND))
28
29 #define AA_AUDIT_FILE_MASK (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
30 AA_MAY_CREATE | AA_MAY_DELETE | \
31 AA_MAY_GETATTR | AA_MAY_SETATTR | \
32 AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
33 AA_EXEC_MMAP | AA_MAY_LINK)
34
35 #define file_ctx(X) ((struct aa_file_ctx *)(X)->f_security)
36
37 /* struct aa_file_ctx - the AppArmor context the file was opened in
38 * @lock: lock to update the ctx
39 * @label: label currently cached on the ctx
40 * @perms: the permission the file was opened with
41 */
42 struct aa_file_ctx {
43 spinlock_t lock;
44 struct aa_label __rcu *label;
45 u32 allow;
46 };
47
48 /**
49 * aa_alloc_file_ctx - allocate file_ctx
50 * @label: initial label of task creating the file
51 * @gfp: gfp flags for allocation
52 *
53 * Returns: file_ctx or NULL on failure
54 */
aa_alloc_file_ctx(struct aa_label * label,gfp_t gfp)55 static inline struct aa_file_ctx *aa_alloc_file_ctx(struct aa_label *label,
56 gfp_t gfp)
57 {
58 struct aa_file_ctx *ctx;
59
60 ctx = kzalloc(sizeof(struct aa_file_ctx), gfp);
61 if (ctx) {
62 spin_lock_init(&ctx->lock);
63 rcu_assign_pointer(ctx->label, aa_get_label(label));
64 }
65 return ctx;
66 }
67
68 /**
69 * aa_free_file_ctx - free a file_ctx
70 * @ctx: file_ctx to free (MAYBE_NULL)
71 */
aa_free_file_ctx(struct aa_file_ctx * ctx)72 static inline void aa_free_file_ctx(struct aa_file_ctx *ctx)
73 {
74 if (ctx) {
75 aa_put_label(rcu_access_pointer(ctx->label));
76 kzfree(ctx);
77 }
78 }
79
aa_get_file_label(struct aa_file_ctx * ctx)80 static inline struct aa_label *aa_get_file_label(struct aa_file_ctx *ctx)
81 {
82 return aa_get_label_rcu(&ctx->label);
83 }
84
85 /*
86 * The xindex is broken into 3 parts
87 * - index - an index into either the exec name table or the variable table
88 * - exec type - which determines how the executable name and index are used
89 * - flags - which modify how the destination name is applied
90 */
91 #define AA_X_INDEX_MASK 0x03ff
92
93 #define AA_X_TYPE_MASK 0x0c00
94 #define AA_X_TYPE_SHIFT 10
95 #define AA_X_NONE 0x0000
96 #define AA_X_NAME 0x0400 /* use executable name px */
97 #define AA_X_TABLE 0x0800 /* use a specified name ->n# */
98
99 #define AA_X_UNSAFE 0x1000
100 #define AA_X_CHILD 0x2000 /* make >AA_X_NONE apply to children */
101 #define AA_X_INHERIT 0x4000
102 #define AA_X_UNCONFINED 0x8000
103
104 /* need to make conditional which ones are being set */
105 struct path_cond {
106 kuid_t uid;
107 umode_t mode;
108 };
109
110 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
111
112 /* FIXME: split perms from dfa and match this to description
113 * also add delegation info.
114 */
dfa_map_xindex(u16 mask)115 static inline u16 dfa_map_xindex(u16 mask)
116 {
117 u16 old_index = (mask >> 10) & 0xf;
118 u16 index = 0;
119
120 if (mask & 0x100)
121 index |= AA_X_UNSAFE;
122 if (mask & 0x200)
123 index |= AA_X_INHERIT;
124 if (mask & 0x80)
125 index |= AA_X_UNCONFINED;
126
127 if (old_index == 1) {
128 index |= AA_X_UNCONFINED;
129 } else if (old_index == 2) {
130 index |= AA_X_NAME;
131 } else if (old_index == 3) {
132 index |= AA_X_NAME | AA_X_CHILD;
133 } else if (old_index) {
134 index |= AA_X_TABLE;
135 index |= old_index - 4;
136 }
137
138 return index;
139 }
140
141 /*
142 * map old dfa inline permissions to new format
143 */
144 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
145 ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
146 #define dfa_user_audit(dfa, state) ((ACCEPT_TABLE2(dfa)[state]) & 0x7f)
147 #define dfa_user_quiet(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 7) & 0x7f)
148 #define dfa_user_xindex(dfa, state) \
149 (dfa_map_xindex(ACCEPT_TABLE(dfa)[state] & 0x3fff))
150
151 #define dfa_other_allow(dfa, state) ((((ACCEPT_TABLE(dfa)[state]) >> 14) & \
152 0x7f) | \
153 ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
154 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
155 #define dfa_other_quiet(dfa, state) \
156 ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
157 #define dfa_other_xindex(dfa, state) \
158 dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
159
160 int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
161 const char *op, u32 request, const char *name,
162 const char *target, struct aa_label *tlabel, kuid_t ouid,
163 const char *info, int error);
164
165 /**
166 * struct aa_file_rules - components used for file rule permissions
167 * @dfa: dfa to match path names and conditionals against
168 * @perms: permission table indexed by the matched state accept entry of @dfa
169 * @trans: transition table for indexed by named x transitions
170 *
171 * File permission are determined by matching a path against @dfa and then
172 * then using the value of the accept entry for the matching state as
173 * an index into @perms. If a named exec transition is required it is
174 * looked up in the transition table.
175 */
176 struct aa_file_rules {
177 unsigned int start;
178 struct aa_dfa *dfa;
179 /* struct perms perms; */
180 struct aa_domain trans;
181 /* TODO: add delegate table */
182 };
183
184 struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
185 struct path_cond *cond);
186 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
187 const char *name, struct path_cond *cond,
188 struct aa_perms *perms);
189
190 int __aa_path_perm(const char *op, struct aa_profile *profile,
191 const char *name, u32 request, struct path_cond *cond,
192 int flags, struct aa_perms *perms);
193 int aa_path_perm(const char *op, struct aa_label *label,
194 const struct path *path, int flags, u32 request,
195 struct path_cond *cond);
196
197 int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
198 const struct path *new_dir, struct dentry *new_dentry);
199
200 int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
201 u32 request);
202
203 void aa_inherit_files(const struct cred *cred, struct files_struct *files);
204
aa_free_file_rules(struct aa_file_rules * rules)205 static inline void aa_free_file_rules(struct aa_file_rules *rules)
206 {
207 aa_put_dfa(rules->dfa);
208 aa_free_domain_entries(&rules->trans);
209 }
210
211 /**
212 * aa_map_file_perms - map file flags to AppArmor permissions
213 * @file: open file to map flags to AppArmor permissions
214 *
215 * Returns: apparmor permission set for the file
216 */
aa_map_file_to_perms(struct file * file)217 static inline u32 aa_map_file_to_perms(struct file *file)
218 {
219 int flags = file->f_flags;
220 u32 perms = 0;
221
222 if (file->f_mode & FMODE_WRITE)
223 perms |= MAY_WRITE;
224 if (file->f_mode & FMODE_READ)
225 perms |= MAY_READ;
226
227 if ((flags & O_APPEND) && (perms & MAY_WRITE))
228 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
229 /* trunc implies write permission */
230 if (flags & O_TRUNC)
231 perms |= MAY_WRITE;
232 if (flags & O_CREAT)
233 perms |= AA_MAY_CREATE;
234
235 return perms;
236 }
237
238 #endif /* __AA_FILE_H */
239