1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * AppArmor security module
4 *
5 * This file contains AppArmor file mediation function definitions.
6 *
7 * Copyright (C) 1998-2008 Novell/SUSE
8 * Copyright 2009-2010 Canonical Ltd.
9 */
10
11 #ifndef __AA_FILE_H
12 #define __AA_FILE_H
13
14 #include <linux/spinlock.h>
15
16 #include "domain.h"
17 #include "match.h"
18 #include "perms.h"
19
20 struct aa_profile;
21 struct path;
22
23 #define mask_mode_t(X) (X & (MAY_EXEC | MAY_WRITE | MAY_READ | MAY_APPEND))
24
25 #define AA_AUDIT_FILE_MASK (MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND |\
26 AA_MAY_CREATE | AA_MAY_DELETE | \
27 AA_MAY_GETATTR | AA_MAY_SETATTR | \
28 AA_MAY_CHMOD | AA_MAY_CHOWN | AA_MAY_LOCK | \
29 AA_EXEC_MMAP | AA_MAY_LINK)
30
file_ctx(struct file * file)31 static inline struct aa_file_ctx *file_ctx(struct file *file)
32 {
33 return file->f_security + apparmor_blob_sizes.lbs_file;
34 }
35
36 /* struct aa_file_ctx - the AppArmor context the file was opened in
37 * @lock: lock to update the ctx
38 * @label: label currently cached on the ctx
39 * @perms: the permission the file was opened with
40 */
41 struct aa_file_ctx {
42 spinlock_t lock;
43 struct aa_label __rcu *label;
44 u32 allow;
45 };
46
47 /**
48 * aa_alloc_file_ctx - allocate file_ctx
49 * @label: initial label of task creating the file
50 * @gfp: gfp flags for allocation
51 *
52 * Returns: file_ctx or NULL on failure
53 */
aa_alloc_file_ctx(struct aa_label * label,gfp_t gfp)54 static inline struct aa_file_ctx *aa_alloc_file_ctx(struct aa_label *label,
55 gfp_t gfp)
56 {
57 struct aa_file_ctx *ctx;
58
59 ctx = kzalloc(sizeof(struct aa_file_ctx), gfp);
60 if (ctx) {
61 spin_lock_init(&ctx->lock);
62 rcu_assign_pointer(ctx->label, aa_get_label(label));
63 }
64 return ctx;
65 }
66
67 /**
68 * aa_free_file_ctx - free a file_ctx
69 * @ctx: file_ctx to free (MAYBE_NULL)
70 */
aa_free_file_ctx(struct aa_file_ctx * ctx)71 static inline void aa_free_file_ctx(struct aa_file_ctx *ctx)
72 {
73 if (ctx) {
74 aa_put_label(rcu_access_pointer(ctx->label));
75 kfree_sensitive(ctx);
76 }
77 }
78
aa_get_file_label(struct aa_file_ctx * ctx)79 static inline struct aa_label *aa_get_file_label(struct aa_file_ctx *ctx)
80 {
81 return aa_get_label_rcu(&ctx->label);
82 }
83
84 /*
85 * The xindex is broken into 3 parts
86 * - index - an index into either the exec name table or the variable table
87 * - exec type - which determines how the executable name and index are used
88 * - flags - which modify how the destination name is applied
89 */
90 #define AA_X_INDEX_MASK 0x03ff
91
92 #define AA_X_TYPE_MASK 0x0c00
93 #define AA_X_TYPE_SHIFT 10
94 #define AA_X_NONE 0x0000
95 #define AA_X_NAME 0x0400 /* use executable name px */
96 #define AA_X_TABLE 0x0800 /* use a specified name ->n# */
97
98 #define AA_X_UNSAFE 0x1000
99 #define AA_X_CHILD 0x2000 /* make >AA_X_NONE apply to children */
100 #define AA_X_INHERIT 0x4000
101 #define AA_X_UNCONFINED 0x8000
102
103 /* need to make conditional which ones are being set */
104 struct path_cond {
105 kuid_t uid;
106 umode_t mode;
107 };
108
109 #define COMBINED_PERM_MASK(X) ((X).allow | (X).audit | (X).quiet | (X).kill)
110
111 /* FIXME: split perms from dfa and match this to description
112 * also add delegation info.
113 */
dfa_map_xindex(u16 mask)114 static inline u16 dfa_map_xindex(u16 mask)
115 {
116 u16 old_index = (mask >> 10) & 0xf;
117 u16 index = 0;
118
119 if (mask & 0x100)
120 index |= AA_X_UNSAFE;
121 if (mask & 0x200)
122 index |= AA_X_INHERIT;
123 if (mask & 0x80)
124 index |= AA_X_UNCONFINED;
125
126 if (old_index == 1) {
127 index |= AA_X_UNCONFINED;
128 } else if (old_index == 2) {
129 index |= AA_X_NAME;
130 } else if (old_index == 3) {
131 index |= AA_X_NAME | AA_X_CHILD;
132 } else if (old_index) {
133 index |= AA_X_TABLE;
134 index |= old_index - 4;
135 }
136
137 return index;
138 }
139
140 /*
141 * map old dfa inline permissions to new format
142 */
143 #define dfa_user_allow(dfa, state) (((ACCEPT_TABLE(dfa)[state]) & 0x7f) | \
144 ((ACCEPT_TABLE(dfa)[state]) & 0x80000000))
145 #define dfa_user_xbits(dfa, state) (((ACCEPT_TABLE(dfa)[state]) >> 7) & 0x7f)
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_xbits(dfa, state) \
155 ((((ACCEPT_TABLE(dfa)[state]) >> 7) >> 14) & 0x7f)
156 #define dfa_other_audit(dfa, state) (((ACCEPT_TABLE2(dfa)[state]) >> 14) & 0x7f)
157 #define dfa_other_quiet(dfa, state) \
158 ((((ACCEPT_TABLE2(dfa)[state]) >> 7) >> 14) & 0x7f)
159 #define dfa_other_xindex(dfa, state) \
160 dfa_map_xindex((ACCEPT_TABLE(dfa)[state] >> 14) & 0x3fff)
161
162 int aa_audit_file(struct aa_profile *profile, struct aa_perms *perms,
163 const char *op, u32 request, const char *name,
164 const char *target, struct aa_label *tlabel, kuid_t ouid,
165 const char *info, int error);
166
167 /**
168 * struct aa_file_rules - components used for file rule permissions
169 * @dfa: dfa to match path names and conditionals against
170 * @perms: permission table indexed by the matched state accept entry of @dfa
171 * @trans: transition table for indexed by named x transitions
172 *
173 * File permission are determined by matching a path against @dfa and
174 * then using the value of the accept entry for the matching state as
175 * an index into @perms. If a named exec transition is required it is
176 * looked up in the transition table.
177 */
178 struct aa_file_rules {
179 unsigned int start;
180 struct aa_dfa *dfa;
181 /* struct perms perms; */
182 struct aa_domain trans;
183 /* TODO: add delegate table */
184 };
185
186 struct aa_perms aa_compute_fperms(struct aa_dfa *dfa, unsigned int state,
187 struct path_cond *cond);
188 unsigned int aa_str_perms(struct aa_dfa *dfa, unsigned int start,
189 const char *name, struct path_cond *cond,
190 struct aa_perms *perms);
191
192 int __aa_path_perm(const char *op, struct aa_profile *profile,
193 const char *name, u32 request, struct path_cond *cond,
194 int flags, struct aa_perms *perms);
195 int aa_path_perm(const char *op, struct aa_label *label,
196 const struct path *path, int flags, u32 request,
197 struct path_cond *cond);
198
199 int aa_path_link(struct aa_label *label, struct dentry *old_dentry,
200 const struct path *new_dir, struct dentry *new_dentry);
201
202 int aa_file_perm(const char *op, struct aa_label *label, struct file *file,
203 u32 request, bool in_atomic);
204
205 void aa_inherit_files(const struct cred *cred, struct files_struct *files);
206
aa_free_file_rules(struct aa_file_rules * rules)207 static inline void aa_free_file_rules(struct aa_file_rules *rules)
208 {
209 aa_put_dfa(rules->dfa);
210 aa_free_domain_entries(&rules->trans);
211 }
212
213 /**
214 * aa_map_file_perms - map file flags to AppArmor permissions
215 * @file: open file to map flags to AppArmor permissions
216 *
217 * Returns: apparmor permission set for the file
218 */
aa_map_file_to_perms(struct file * file)219 static inline u32 aa_map_file_to_perms(struct file *file)
220 {
221 int flags = file->f_flags;
222 u32 perms = 0;
223
224 if (file->f_mode & FMODE_WRITE)
225 perms |= MAY_WRITE;
226 if (file->f_mode & FMODE_READ)
227 perms |= MAY_READ;
228
229 if ((flags & O_APPEND) && (perms & MAY_WRITE))
230 perms = (perms & ~MAY_WRITE) | MAY_APPEND;
231 /* trunc implies write permission */
232 if (flags & O_TRUNC)
233 perms |= MAY_WRITE;
234 if (flags & O_CREAT)
235 perms |= AA_MAY_CREATE;
236
237 return perms;
238 }
239
240 #endif /* __AA_FILE_H */
241