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
71 #define fix_derived_permission(x) \
73 (x)->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(x)->d_uid); \
74 (x)->i_gid = make_kgid(&init_user_ns, get_gid(SDCARDFS_I(x))); \
75 (x)->i_mode = ((x)->i_mode & S_IFMT) | get_mode(SDCARDFS_I(x));\
79 /* OVERRIDE_CRED() and REVERT_CRED()
81 * backup original task->cred
82 * and modifies task->cred->fsuid/fsgid to specified value.
84 * restore original task->cred->fsuid/fsgid.
85 * These two macro should be used in pair, and OVERRIDE_CRED() should be
86 * placed at the beginning of a function, right after variable declaration.
88 #define OVERRIDE_CRED(sdcardfs_sbi, saved_cred) \
89 saved_cred = override_fsids(sdcardfs_sbi); \
90 if (!saved_cred) { return -ENOMEM; }
92 #define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred) \
93 saved_cred = override_fsids(sdcardfs_sbi); \
94 if (!saved_cred) { return ERR_PTR(-ENOMEM); }
96 #define REVERT_CRED(saved_cred) revert_fsids(saved_cred)
98 #define DEBUG_CRED() \
99 printk("KAKJAGI: %s:%d fsuid %d fsgid %d\n", \
100 __FUNCTION__, __LINE__, \
101 (int)current->cred->fsuid, \
102 (int)current->cred->fsgid);
104 /* Android 5.0 support */
106 /* Permission mode for a specific node. Controls how file permissions
107 * are derived for children nodes. */
109 /* Nothing special; this node should just inherit from its parent. */
111 /* This node is one level above a normal root; used for legacy layouts
112 * which use the first level to represent user_id. */
114 /* This node is "/" */
116 /* This node is "/Android" */
118 /* This node is "/Android/data" */
120 /* This node is "/Android/obb" */
122 /* This node is "/Android/media" */
126 struct sdcardfs_sb_info;
127 struct sdcardfs_mount_options;
129 /* Do not directly use this function. Use OVERRIDE_CRED() instead. */
130 const struct cred * override_fsids(struct sdcardfs_sb_info* sbi);
131 /* Do not directly use this function, use REVERT_CRED() instead. */
132 void revert_fsids(const struct cred * old_cred);
134 /* operations vectors defined in specific files */
135 extern const struct file_operations sdcardfs_main_fops;
136 extern const struct file_operations sdcardfs_dir_fops;
137 extern const struct inode_operations sdcardfs_main_iops;
138 extern const struct inode_operations sdcardfs_dir_iops;
139 extern const struct inode_operations sdcardfs_symlink_iops;
140 extern const struct super_operations sdcardfs_sops;
141 extern const struct dentry_operations sdcardfs_ci_dops;
142 extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
143 extern const struct vm_operations_struct sdcardfs_vm_ops;
145 extern int sdcardfs_init_inode_cache(void);
146 extern void sdcardfs_destroy_inode_cache(void);
147 extern int sdcardfs_init_dentry_cache(void);
148 extern void sdcardfs_destroy_dentry_cache(void);
149 extern int new_dentry_private_data(struct dentry *dentry);
150 extern void free_dentry_private_data(struct dentry *dentry);
151 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
153 extern struct inode *sdcardfs_iget(struct super_block *sb,
154 struct inode *lower_inode, userid_t id);
155 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
156 struct path *lower_path, userid_t id);
158 /* file private data */
159 struct sdcardfs_file_info {
160 struct file *lower_file;
161 const struct vm_operations_struct *lower_vm_ops;
164 /* sdcardfs inode data in memory */
165 struct sdcardfs_inode_info {
166 struct inode *lower_inode;
167 /* state derived based on current position in hierachy */
173 struct inode vfs_inode;
177 /* sdcardfs dentry data in memory */
178 struct sdcardfs_dentry_info {
179 spinlock_t lock; /* protects lower_path */
180 struct path lower_path;
181 struct path orig_path;
184 struct sdcardfs_mount_options {
191 unsigned int reserved_mb;
194 /* sdcardfs super-block data in memory */
195 struct sdcardfs_sb_info {
196 struct super_block *sb;
197 struct super_block *lower_sb;
198 /* derived perm policy : some of options have been added
199 * to sdcardfs_mount_options (Android 4.4 support) */
200 struct sdcardfs_mount_options options;
201 spinlock_t lock; /* protects obbpath */
205 struct list_head list;
209 * inode to private data
211 * Since we use containers and the struct inode is _inside_ the
212 * sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
213 * inode pointer), return a valid non-NULL pointer.
215 static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
217 return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
220 /* dentry to private data */
221 #define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
223 /* superblock to private data */
224 #define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
226 /* file to private Data */
227 #define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
229 /* file to lower file */
230 static inline struct file *sdcardfs_lower_file(const struct file *f)
232 return SDCARDFS_F(f)->lower_file;
235 static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
237 SDCARDFS_F(f)->lower_file = val;
240 /* inode to lower inode. */
241 static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
243 return SDCARDFS_I(i)->lower_inode;
246 static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
248 SDCARDFS_I(i)->lower_inode = val;
251 /* superblock to lower superblock */
252 static inline struct super_block *sdcardfs_lower_super(
253 const struct super_block *sb)
255 return SDCARDFS_SB(sb)->lower_sb;
258 static inline void sdcardfs_set_lower_super(struct super_block *sb,
259 struct super_block *val)
261 SDCARDFS_SB(sb)->lower_sb = val;
264 /* path based (dentry/mnt) macros */
265 static inline void pathcpy(struct path *dst, const struct path *src)
267 dst->dentry = src->dentry;
271 /* sdcardfs_get_pname functions calls path_get()
272 * therefore, the caller must call "proper" path_put functions
274 #define SDCARDFS_DENT_FUNC(pname) \
275 static inline void sdcardfs_get_##pname(const struct dentry *dent, \
276 struct path *pname) \
278 spin_lock(&SDCARDFS_D(dent)->lock); \
279 pathcpy(pname, &SDCARDFS_D(dent)->pname); \
281 spin_unlock(&SDCARDFS_D(dent)->lock); \
284 static inline void sdcardfs_put_##pname(const struct dentry *dent, \
285 struct path *pname) \
290 static inline void sdcardfs_set_##pname(const struct dentry *dent, \
291 struct path *pname) \
293 spin_lock(&SDCARDFS_D(dent)->lock); \
294 pathcpy(&SDCARDFS_D(dent)->pname, pname); \
295 spin_unlock(&SDCARDFS_D(dent)->lock); \
298 static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
300 spin_lock(&SDCARDFS_D(dent)->lock); \
301 SDCARDFS_D(dent)->pname.dentry = NULL; \
302 SDCARDFS_D(dent)->pname.mnt = NULL; \
303 spin_unlock(&SDCARDFS_D(dent)->lock); \
306 static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
309 spin_lock(&SDCARDFS_D(dent)->lock); \
310 if(SDCARDFS_D(dent)->pname.dentry) { \
311 pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
312 SDCARDFS_D(dent)->pname.dentry = NULL; \
313 SDCARDFS_D(dent)->pname.mnt = NULL; \
314 spin_unlock(&SDCARDFS_D(dent)->lock); \
317 spin_unlock(&SDCARDFS_D(dent)->lock); \
321 SDCARDFS_DENT_FUNC(lower_path)
322 SDCARDFS_DENT_FUNC(orig_path)
324 static inline int get_gid(struct sdcardfs_inode_info *info) {
325 struct sdcardfs_sb_info *sb_info = SDCARDFS_SB(info->vfs_inode.i_sb);
326 if (sb_info->options.gid == AID_SDCARD_RW) {
327 /* As an optimization, certain trusted system components only run
328 * as owner but operate across all users. Since we're now handing
329 * out the sdcard_rw GID only to trusted apps, we're okay relaxing
330 * the user boundary enforcement for the default view. The UIDs
331 * assigned to app directories are still multiuser aware. */
332 return AID_SDCARD_RW;
334 return multiuser_get_uid(info->userid, sb_info->options.gid);
337 static inline int get_mode(struct sdcardfs_inode_info *info) {
340 struct sdcardfs_sb_info *sb_info = SDCARDFS_SB(info->vfs_inode.i_sb);
341 int visible_mode = 0775 & ~sb_info->options.mask;
343 if (info->perm == PERM_PRE_ROOT) {
344 /* Top of multi-user view should always be visible to ensure
345 * secondary users can traverse inside. */
347 } else if (info->under_android) {
348 /* Block "other" access to Android directories, since only apps
349 * belonging to a specific user should be in there; we still
350 * leave +x open for the default view. */
351 if (sb_info->options.gid == AID_SDCARD_RW) {
352 visible_mode = visible_mode & ~0006;
354 visible_mode = visible_mode & ~0007;
357 owner_mode = info->lower_inode->i_mode & 0700;
358 filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
359 return filtered_mode;
362 static inline int has_graft_path(const struct dentry *dent)
366 spin_lock(&SDCARDFS_D(dent)->lock);
367 if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
369 spin_unlock(&SDCARDFS_D(dent)->lock);
374 static inline void sdcardfs_get_real_lower(const struct dentry *dent,
375 struct path *real_lower)
377 /* in case of a local obb dentry
378 * the orig_path should be returned
380 if(has_graft_path(dent))
381 sdcardfs_get_orig_path(dent, real_lower);
383 sdcardfs_get_lower_path(dent, real_lower);
386 static inline void sdcardfs_put_real_lower(const struct dentry *dent,
387 struct path *real_lower)
389 if(has_graft_path(dent))
390 sdcardfs_put_orig_path(dent, real_lower);
392 sdcardfs_put_lower_path(dent, real_lower);
395 extern struct mutex sdcardfs_super_list_lock;
396 extern struct list_head sdcardfs_super_list;
398 /* for packagelist.c */
399 extern appid_t get_appid(void *pkgl_id, const char *app_name);
400 extern int check_caller_access_to_name(struct inode *parent_node, const char* name);
401 extern int open_flags_to_access_mode(int open_flags);
402 extern int packagelist_init(void);
403 extern void packagelist_exit(void);
405 /* for derived_perm.c */
406 extern void setup_derived_state(struct inode *inode, perm_t perm,
407 userid_t userid, uid_t uid, bool under_android);
408 extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
409 extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, struct dentry *newdentry);
410 extern void get_derive_permissions_recursive(struct dentry *parent);
412 extern void update_derived_permission_lock(struct dentry *dentry);
413 extern int need_graft_path(struct dentry *dentry);
414 extern int is_base_obbpath(struct dentry *dentry);
415 extern int is_obbpath_invalid(struct dentry *dentry);
416 extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
418 /* locking helpers */
419 static inline struct dentry *lock_parent(struct dentry *dentry)
421 struct dentry *dir = dget_parent(dentry);
422 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
426 static inline void unlock_dir(struct dentry *dir)
428 mutex_unlock(&d_inode(dir)->i_mutex);
432 static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
439 dent = kern_path_locked(path_s, &parent);
447 err = vfs_mkdir(d_inode(parent.dentry), dent, mode);
454 attrs.ia_uid = make_kuid(&init_user_ns, uid);
455 attrs.ia_gid = make_kgid(&init_user_ns, gid);
456 attrs.ia_valid = ATTR_UID | ATTR_GID;
457 mutex_lock(&d_inode(dent)->i_mutex);
458 notify_change(dent, &attrs, NULL);
459 mutex_unlock(&d_inode(dent)->i_mutex);
465 /* parent dentry locked by lookup_create */
466 mutex_unlock(&d_inode(parent.dentry)->i_mutex);
472 * Return 1, if a disk has enough free space, otherwise 0.
473 * We assume that any files can not be overwritten.
475 static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
478 struct path lower_path;
479 struct kstatfs statfs;
481 struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
483 if (sbi->options.reserved_mb) {
484 /* Get fs stat of lower filesystem. */
485 sdcardfs_get_lower_path(dentry, &lower_path);
486 err = vfs_statfs(&lower_path, &statfs);
487 sdcardfs_put_lower_path(dentry, &lower_path);
492 /* Invalid statfs informations. */
493 if (unlikely(statfs.f_bsize == 0))
496 /* if you are checking directory, set size to f_bsize. */
498 size = statfs.f_bsize;
501 avail = statfs.f_bavail * statfs.f_bsize;
503 /* not enough space */
504 if ((u64)size > avail)
508 if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
516 /* Copies attrs and maintains sdcardfs managed attrs */
517 static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
519 dest->i_mode = (src->i_mode & S_IFMT) | get_mode(SDCARDFS_I(dest));
520 dest->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(dest)->d_uid);
521 dest->i_gid = make_kgid(&init_user_ns, get_gid(SDCARDFS_I(dest)));
522 dest->i_rdev = src->i_rdev;
523 dest->i_atime = src->i_atime;
524 dest->i_mtime = src->i_mtime;
525 dest->i_ctime = src->i_ctime;
526 dest->i_blkbits = src->i_blkbits;
527 dest->i_flags = src->i_flags;
528 set_nlink(dest, src->i_nlink);
530 #endif /* not _SDCARDFS_H_ */