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