2 * fs/sdcardfs/sdcardfs.h
5 * This file system replaces the sdcard daemon on Android
6 * On version 2.0, some of the daemon functions have been ported
7 * to support the multi-user concepts of Android 4.4
9 * Copyright (c) 2013 Samsung Electronics Co. Ltd
10 * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
11 * Sunghwan Yun, Sungjong Seo
13 * This program has been developed as a stackable file system based on
14 * the WrapFS which written by
16 * Copyright (c) 1998-2011 Erez Zadok
17 * Copyright (c) 2009 Shrikar Archak
18 * Copyright (c) 2003-2011 Stony Brook University
19 * Copyright (c) 2003-2011 The Research Foundation of SUNY
21 * This file is dual licensed. It may be redistributed and/or modified
22 * under the terms of the Apache 2.0 License OR version 2 of the GNU
23 * General Public License.
29 #include <linux/dcache.h>
30 #include <linux/file.h>
33 #include <linux/mount.h>
34 #include <linux/namei.h>
35 #include <linux/seq_file.h>
36 #include <linux/statfs.h>
37 #include <linux/fs_stack.h>
38 #include <linux/magic.h>
39 #include <linux/uaccess.h>
40 #include <linux/slab.h>
41 #include <linux/sched.h>
42 #include <linux/types.h>
43 #include <linux/security.h>
44 #include <linux/string.h>
45 #include <linux/list.h>
46 #include "multiuser.h"
48 /* the file system name */
49 #define SDCARDFS_NAME "sdcardfs"
51 /* sdcardfs root inode number */
52 #define SDCARDFS_ROOT_INO 1
54 /* useful for tracking code reachability */
55 #define UDBG printk(KERN_DEFAULT "DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
57 #define SDCARDFS_DIRENT_SIZE 256
59 /* temporary static uid settings for development */
60 #define AID_ROOT 0 /* uid for accessing /mnt/sdcard & extSdcard */
61 #define AID_MEDIA_RW 1023 /* internal media storage write access */
63 #define AID_SDCARD_RW 1015 /* external storage write access */
64 #define AID_SDCARD_R 1028 /* external storage read access */
65 #define AID_SDCARD_PICS 1033 /* external storage photos access */
66 #define AID_SDCARD_AV 1034 /* external storage audio/video access */
67 #define AID_SDCARD_ALL 1035 /* access all users external storage */
69 #define AID_PACKAGE_INFO 1027
73 * Permissions are handled by our permission function.
74 * We don't want anyone who happens to look at our inode value to prematurely
75 * block access, so store more permissive values. These are probably never
78 #define fixup_tmp_permissions(x) \
80 (x)->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(x)->d_uid); \
81 (x)->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW); \
82 (x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
85 /* OVERRIDE_CRED() and REVERT_CRED()
87 * backup original task->cred
88 * and modifies task->cred->fsuid/fsgid to specified value.
90 * restore original task->cred->fsuid/fsgid.
91 * These two macro should be used in pair, and OVERRIDE_CRED() should be
92 * placed at the beginning of a function, right after variable declaration.
94 #define OVERRIDE_CRED(sdcardfs_sbi, saved_cred) \
95 saved_cred = override_fsids(sdcardfs_sbi); \
96 if (!saved_cred) { return -ENOMEM; }
98 #define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred) \
99 saved_cred = override_fsids(sdcardfs_sbi); \
100 if (!saved_cred) { return ERR_PTR(-ENOMEM); }
102 #define REVERT_CRED(saved_cred) revert_fsids(saved_cred)
104 #define DEBUG_CRED() \
105 printk("KAKJAGI: %s:%d fsuid %d fsgid %d\n", \
106 __FUNCTION__, __LINE__, \
107 (int)current->cred->fsuid, \
108 (int)current->cred->fsgid);
110 /* Android 5.0 support */
112 /* Permission mode for a specific node. Controls how file permissions
113 * are derived for children nodes. */
115 /* Nothing special; this node should just inherit from its parent. */
117 /* This node is one level above a normal root; used for legacy layouts
118 * which use the first level to represent user_id. */
120 /* This node is "/" */
122 /* This node is "/Android" */
124 /* This node is "/Android/data" */
126 /* This node is "/Android/obb" */
128 /* This node is "/Android/media" */
132 struct sdcardfs_sb_info;
133 struct sdcardfs_mount_options;
135 /* Do not directly use this function. Use OVERRIDE_CRED() instead. */
136 const struct cred * override_fsids(struct sdcardfs_sb_info* sbi);
137 /* Do not directly use this function, use REVERT_CRED() instead. */
138 void revert_fsids(const struct cred * old_cred);
140 /* operations vectors defined in specific files */
141 extern const struct file_operations sdcardfs_main_fops;
142 extern const struct file_operations sdcardfs_dir_fops;
143 extern const struct inode_operations sdcardfs_main_iops;
144 extern const struct inode_operations sdcardfs_dir_iops;
145 extern const struct inode_operations sdcardfs_symlink_iops;
146 extern const struct super_operations sdcardfs_sops;
147 extern const struct dentry_operations sdcardfs_ci_dops;
148 extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
149 extern const struct vm_operations_struct sdcardfs_vm_ops;
151 extern int sdcardfs_init_inode_cache(void);
152 extern void sdcardfs_destroy_inode_cache(void);
153 extern int sdcardfs_init_dentry_cache(void);
154 extern void sdcardfs_destroy_dentry_cache(void);
155 extern int new_dentry_private_data(struct dentry *dentry);
156 extern void free_dentry_private_data(struct dentry *dentry);
157 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
159 extern struct inode *sdcardfs_iget(struct super_block *sb,
160 struct inode *lower_inode, userid_t id);
161 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
162 struct path *lower_path, userid_t id);
164 /* file private data */
165 struct sdcardfs_file_info {
166 struct file *lower_file;
167 const struct vm_operations_struct *lower_vm_ops;
170 /* sdcardfs inode data in memory */
171 struct sdcardfs_inode_info {
172 struct inode *lower_inode;
173 /* state derived based on current position in hierachy */
178 /* top folder for ownership */
181 struct inode vfs_inode;
185 /* sdcardfs dentry data in memory */
186 struct sdcardfs_dentry_info {
187 spinlock_t lock; /* protects lower_path */
188 struct path lower_path;
189 struct path orig_path;
192 struct sdcardfs_mount_options {
197 unsigned int reserved_mb;
200 struct sdcardfs_vfsmount_options {
205 extern int parse_options_remount(struct super_block *sb, char *options, int silent,
206 struct sdcardfs_vfsmount_options *vfsopts);
208 /* sdcardfs super-block data in memory */
209 struct sdcardfs_sb_info {
210 struct super_block *sb;
211 struct super_block *lower_sb;
212 /* derived perm policy : some of options have been added
213 * to sdcardfs_mount_options (Android 4.4 support) */
214 struct sdcardfs_mount_options options;
215 spinlock_t lock; /* protects obbpath */
219 struct list_head list;
223 * inode to private data
225 * Since we use containers and the struct inode is _inside_ the
226 * sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
227 * inode pointer), return a valid non-NULL pointer.
229 static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
231 return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
234 /* dentry to private data */
235 #define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
237 /* superblock to private data */
238 #define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
240 /* file to private Data */
241 #define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
243 /* file to lower file */
244 static inline struct file *sdcardfs_lower_file(const struct file *f)
246 return SDCARDFS_F(f)->lower_file;
249 static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
251 SDCARDFS_F(f)->lower_file = val;
254 /* inode to lower inode. */
255 static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
257 return SDCARDFS_I(i)->lower_inode;
260 static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
262 SDCARDFS_I(i)->lower_inode = val;
265 /* superblock to lower superblock */
266 static inline struct super_block *sdcardfs_lower_super(
267 const struct super_block *sb)
269 return SDCARDFS_SB(sb)->lower_sb;
272 static inline void sdcardfs_set_lower_super(struct super_block *sb,
273 struct super_block *val)
275 SDCARDFS_SB(sb)->lower_sb = val;
278 /* path based (dentry/mnt) macros */
279 static inline void pathcpy(struct path *dst, const struct path *src)
281 dst->dentry = src->dentry;
285 /* sdcardfs_get_pname functions calls path_get()
286 * therefore, the caller must call "proper" path_put functions
288 #define SDCARDFS_DENT_FUNC(pname) \
289 static inline void sdcardfs_get_##pname(const struct dentry *dent, \
290 struct path *pname) \
292 spin_lock(&SDCARDFS_D(dent)->lock); \
293 pathcpy(pname, &SDCARDFS_D(dent)->pname); \
295 spin_unlock(&SDCARDFS_D(dent)->lock); \
298 static inline void sdcardfs_put_##pname(const struct dentry *dent, \
299 struct path *pname) \
304 static inline void sdcardfs_set_##pname(const struct dentry *dent, \
305 struct path *pname) \
307 spin_lock(&SDCARDFS_D(dent)->lock); \
308 pathcpy(&SDCARDFS_D(dent)->pname, pname); \
309 spin_unlock(&SDCARDFS_D(dent)->lock); \
312 static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
314 spin_lock(&SDCARDFS_D(dent)->lock); \
315 SDCARDFS_D(dent)->pname.dentry = NULL; \
316 SDCARDFS_D(dent)->pname.mnt = NULL; \
317 spin_unlock(&SDCARDFS_D(dent)->lock); \
320 static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
323 spin_lock(&SDCARDFS_D(dent)->lock); \
324 if(SDCARDFS_D(dent)->pname.dentry) { \
325 pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
326 SDCARDFS_D(dent)->pname.dentry = NULL; \
327 SDCARDFS_D(dent)->pname.mnt = NULL; \
328 spin_unlock(&SDCARDFS_D(dent)->lock); \
331 spin_unlock(&SDCARDFS_D(dent)->lock); \
335 SDCARDFS_DENT_FUNC(lower_path)
336 SDCARDFS_DENT_FUNC(orig_path)
338 /* grab a refererence if we aren't linking to ourself */
339 static inline void set_top(struct sdcardfs_inode_info *info, struct inode *top)
341 struct inode *old_top = NULL;
342 BUG_ON(IS_ERR_OR_NULL(top));
343 if (info->top && info->top != &info->vfs_inode) {
346 if (top != &info->vfs_inode)
352 static inline struct inode *grab_top(struct sdcardfs_inode_info *info)
354 struct inode *top = info->top;
362 static inline void release_top(struct sdcardfs_inode_info *info)
367 static inline int get_gid(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
368 struct sdcardfs_vfsmount_options *opts = mnt->data;
370 if (opts->gid == AID_SDCARD_RW) {
371 /* As an optimization, certain trusted system components only run
372 * as owner but operate across all users. Since we're now handing
373 * out the sdcard_rw GID only to trusted apps, we're okay relaxing
374 * the user boundary enforcement for the default view. The UIDs
375 * assigned to app directories are still multiuser aware. */
376 return AID_SDCARD_RW;
378 return multiuser_get_uid(info->userid, opts->gid);
381 static inline int get_mode(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
384 struct sdcardfs_vfsmount_options *opts = mnt->data;
385 int visible_mode = 0775 & ~opts->mask;
388 if (info->perm == PERM_PRE_ROOT) {
389 /* Top of multi-user view should always be visible to ensure
390 * secondary users can traverse inside. */
392 } else if (info->under_android) {
393 /* Block "other" access to Android directories, since only apps
394 * belonging to a specific user should be in there; we still
395 * leave +x open for the default view. */
396 if (opts->gid == AID_SDCARD_RW) {
397 visible_mode = visible_mode & ~0006;
399 visible_mode = visible_mode & ~0007;
402 owner_mode = info->lower_inode->i_mode & 0700;
403 filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
404 return filtered_mode;
407 static inline int has_graft_path(const struct dentry *dent)
411 spin_lock(&SDCARDFS_D(dent)->lock);
412 if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
414 spin_unlock(&SDCARDFS_D(dent)->lock);
419 static inline void sdcardfs_get_real_lower(const struct dentry *dent,
420 struct path *real_lower)
422 /* in case of a local obb dentry
423 * the orig_path should be returned
425 if(has_graft_path(dent))
426 sdcardfs_get_orig_path(dent, real_lower);
428 sdcardfs_get_lower_path(dent, real_lower);
431 static inline void sdcardfs_put_real_lower(const struct dentry *dent,
432 struct path *real_lower)
434 if(has_graft_path(dent))
435 sdcardfs_put_orig_path(dent, real_lower);
437 sdcardfs_put_lower_path(dent, real_lower);
440 extern struct mutex sdcardfs_super_list_lock;
441 extern struct list_head sdcardfs_super_list;
443 /* for packagelist.c */
444 extern appid_t get_appid(const char *app_name);
445 extern int check_caller_access_to_name(struct inode *parent_node, const char* name);
446 extern int open_flags_to_access_mode(int open_flags);
447 extern int packagelist_init(void);
448 extern void packagelist_exit(void);
450 /* for derived_perm.c */
451 extern void setup_derived_state(struct inode *inode, perm_t perm, userid_t userid,
452 uid_t uid, bool under_android, struct inode *top);
453 extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
454 extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, struct dentry *newdentry);
455 extern void fixup_top_recursive(struct dentry *parent);
456 extern void fixup_perms_recursive(struct dentry *dentry, const char *name, size_t len);
458 extern void update_derived_permission_lock(struct dentry *dentry);
459 extern int need_graft_path(struct dentry *dentry);
460 extern int is_base_obbpath(struct dentry *dentry);
461 extern int is_obbpath_invalid(struct dentry *dentry);
462 extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
464 /* locking helpers */
465 static inline struct dentry *lock_parent(struct dentry *dentry)
467 struct dentry *dir = dget_parent(dentry);
468 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
472 static inline void unlock_dir(struct dentry *dir)
474 mutex_unlock(&d_inode(dir)->i_mutex);
478 static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
485 dent = kern_path_locked(path_s, &parent);
493 err = vfs_mkdir2(parent.mnt, d_inode(parent.dentry), dent, mode);
500 attrs.ia_uid = make_kuid(&init_user_ns, uid);
501 attrs.ia_gid = make_kgid(&init_user_ns, gid);
502 attrs.ia_valid = ATTR_UID | ATTR_GID;
503 mutex_lock(&d_inode(dent)->i_mutex);
504 notify_change2(parent.mnt, dent, &attrs, NULL);
505 mutex_unlock(&d_inode(dent)->i_mutex);
511 /* parent dentry locked by lookup_create */
512 mutex_unlock(&d_inode(parent.dentry)->i_mutex);
518 * Return 1, if a disk has enough free space, otherwise 0.
519 * We assume that any files can not be overwritten.
521 static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
524 struct path lower_path;
525 struct kstatfs statfs;
527 struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
529 if (sbi->options.reserved_mb) {
530 /* Get fs stat of lower filesystem. */
531 sdcardfs_get_lower_path(dentry, &lower_path);
532 err = vfs_statfs(&lower_path, &statfs);
533 sdcardfs_put_lower_path(dentry, &lower_path);
538 /* Invalid statfs informations. */
539 if (unlikely(statfs.f_bsize == 0))
542 /* if you are checking directory, set size to f_bsize. */
544 size = statfs.f_bsize;
547 avail = statfs.f_bavail * statfs.f_bsize;
549 /* not enough space */
550 if ((u64)size > avail)
554 if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
563 * Copies attrs and maintains sdcardfs managed attrs
564 * Since our permission check handles all special permissions, set those to be open
566 static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
568 dest->i_mode = (src->i_mode & S_IFMT) | S_IRWXU | S_IRWXG |
569 S_IROTH | S_IXOTH; /* 0775 */
570 dest->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(dest)->d_uid);
571 dest->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW);
572 dest->i_rdev = src->i_rdev;
573 dest->i_atime = src->i_atime;
574 dest->i_mtime = src->i_mtime;
575 dest->i_ctime = src->i_ctime;
576 dest->i_blkbits = src->i_blkbits;
577 dest->i_flags = src->i_flags;
578 set_nlink(dest, src->i_nlink);
580 #endif /* not _SDCARDFS_H_ */