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 */
68 #define AID_MEDIA_OBB 1059 /* obb files */
70 #define AID_SDCARD_IMAGE 1057
72 #define AID_PACKAGE_INFO 1027
76 * Permissions are handled by our permission function.
77 * We don't want anyone who happens to look at our inode value to prematurely
78 * block access, so store more permissive values. These are probably never
81 #define fixup_tmp_permissions(x) \
83 (x)->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(x)->d_uid); \
84 (x)->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW); \
85 (x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
88 /* OVERRIDE_CRED() and REVERT_CRED()
90 * backup original task->cred
91 * and modifies task->cred->fsuid/fsgid to specified value.
93 * restore original task->cred->fsuid/fsgid.
94 * These two macro should be used in pair, and OVERRIDE_CRED() should be
95 * placed at the beginning of a function, right after variable declaration.
97 #define OVERRIDE_CRED(sdcardfs_sbi, saved_cred, info) \
98 saved_cred = override_fsids(sdcardfs_sbi, info); \
99 if (!saved_cred) { return -ENOMEM; }
101 #define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred, info) \
102 saved_cred = override_fsids(sdcardfs_sbi, info); \
103 if (!saved_cred) { return ERR_PTR(-ENOMEM); }
105 #define REVERT_CRED(saved_cred) revert_fsids(saved_cred)
107 #define DEBUG_CRED() \
108 printk("KAKJAGI: %s:%d fsuid %d fsgid %d\n", \
109 __FUNCTION__, __LINE__, \
110 (int)current->cred->fsuid, \
111 (int)current->cred->fsgid);
113 /* Android 5.0 support */
115 /* Permission mode for a specific node. Controls how file permissions
116 * are derived for children nodes. */
118 /* Nothing special; this node should just inherit from its parent. */
120 /* This node is one level above a normal root; used for legacy layouts
121 * which use the first level to represent user_id. */
123 /* This node is "/" */
125 /* This node is "/Android" */
127 /* This node is "/Android/data" */
129 /* This node is "/Android/obb" */
131 /* This node is "/Android/media" */
133 /* This node is "/Android/[data|media|obb]/[package]" */
134 PERM_ANDROID_PACKAGE,
135 /* This node is "/Android/[data|media|obb]/[package]/cache" */
136 PERM_ANDROID_PACKAGE_CACHE,
139 struct sdcardfs_sb_info;
140 struct sdcardfs_mount_options;
141 struct sdcardfs_inode_info;
143 /* Do not directly use this function. Use OVERRIDE_CRED() instead. */
144 const struct cred * override_fsids(struct sdcardfs_sb_info* sbi, struct sdcardfs_inode_info *info);
145 /* Do not directly use this function, use REVERT_CRED() instead. */
146 void revert_fsids(const struct cred * old_cred);
148 /* operations vectors defined in specific files */
149 extern const struct file_operations sdcardfs_main_fops;
150 extern const struct file_operations sdcardfs_dir_fops;
151 extern const struct inode_operations sdcardfs_main_iops;
152 extern const struct inode_operations sdcardfs_dir_iops;
153 extern const struct inode_operations sdcardfs_symlink_iops;
154 extern const struct super_operations sdcardfs_sops;
155 extern const struct dentry_operations sdcardfs_ci_dops;
156 extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
157 extern const struct vm_operations_struct sdcardfs_vm_ops;
159 extern int sdcardfs_init_inode_cache(void);
160 extern void sdcardfs_destroy_inode_cache(void);
161 extern int sdcardfs_init_dentry_cache(void);
162 extern void sdcardfs_destroy_dentry_cache(void);
163 extern int new_dentry_private_data(struct dentry *dentry);
164 extern void free_dentry_private_data(struct dentry *dentry);
165 extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
167 extern struct inode *sdcardfs_iget(struct super_block *sb,
168 struct inode *lower_inode, userid_t id);
169 extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
170 struct path *lower_path, userid_t id);
172 /* file private data */
173 struct sdcardfs_file_info {
174 struct file *lower_file;
175 const struct vm_operations_struct *lower_vm_ops;
178 /* sdcardfs inode data in memory */
179 struct sdcardfs_inode_info {
180 struct inode *lower_inode;
181 /* state derived based on current position in hierachy */
188 /* top folder for ownership */
191 struct inode vfs_inode;
195 /* sdcardfs dentry data in memory */
196 struct sdcardfs_dentry_info {
197 spinlock_t lock; /* protects lower_path */
198 struct path lower_path;
199 struct path orig_path;
202 struct sdcardfs_mount_options {
207 unsigned int reserved_mb;
210 struct sdcardfs_vfsmount_options {
215 extern int parse_options_remount(struct super_block *sb, char *options, int silent,
216 struct sdcardfs_vfsmount_options *vfsopts);
218 /* sdcardfs super-block data in memory */
219 struct sdcardfs_sb_info {
220 struct super_block *sb;
221 struct super_block *lower_sb;
222 /* derived perm policy : some of options have been added
223 * to sdcardfs_mount_options (Android 4.4 support) */
224 struct sdcardfs_mount_options options;
225 spinlock_t lock; /* protects obbpath */
229 struct list_head list;
233 * inode to private data
235 * Since we use containers and the struct inode is _inside_ the
236 * sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
237 * inode pointer), return a valid non-NULL pointer.
239 static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
241 return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
244 /* dentry to private data */
245 #define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
247 /* superblock to private data */
248 #define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
250 /* file to private Data */
251 #define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
253 /* file to lower file */
254 static inline struct file *sdcardfs_lower_file(const struct file *f)
256 return SDCARDFS_F(f)->lower_file;
259 static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
261 SDCARDFS_F(f)->lower_file = val;
264 /* inode to lower inode. */
265 static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
267 return SDCARDFS_I(i)->lower_inode;
270 static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
272 SDCARDFS_I(i)->lower_inode = val;
275 /* superblock to lower superblock */
276 static inline struct super_block *sdcardfs_lower_super(
277 const struct super_block *sb)
279 return SDCARDFS_SB(sb)->lower_sb;
282 static inline void sdcardfs_set_lower_super(struct super_block *sb,
283 struct super_block *val)
285 SDCARDFS_SB(sb)->lower_sb = val;
288 /* path based (dentry/mnt) macros */
289 static inline void pathcpy(struct path *dst, const struct path *src)
291 dst->dentry = src->dentry;
295 /* sdcardfs_get_pname functions calls path_get()
296 * therefore, the caller must call "proper" path_put functions
298 #define SDCARDFS_DENT_FUNC(pname) \
299 static inline void sdcardfs_get_##pname(const struct dentry *dent, \
300 struct path *pname) \
302 spin_lock(&SDCARDFS_D(dent)->lock); \
303 pathcpy(pname, &SDCARDFS_D(dent)->pname); \
305 spin_unlock(&SDCARDFS_D(dent)->lock); \
308 static inline void sdcardfs_put_##pname(const struct dentry *dent, \
309 struct path *pname) \
314 static inline void sdcardfs_set_##pname(const struct dentry *dent, \
315 struct path *pname) \
317 spin_lock(&SDCARDFS_D(dent)->lock); \
318 pathcpy(&SDCARDFS_D(dent)->pname, pname); \
319 spin_unlock(&SDCARDFS_D(dent)->lock); \
322 static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
324 spin_lock(&SDCARDFS_D(dent)->lock); \
325 SDCARDFS_D(dent)->pname.dentry = NULL; \
326 SDCARDFS_D(dent)->pname.mnt = NULL; \
327 spin_unlock(&SDCARDFS_D(dent)->lock); \
330 static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
333 spin_lock(&SDCARDFS_D(dent)->lock); \
334 if(SDCARDFS_D(dent)->pname.dentry) { \
335 pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
336 SDCARDFS_D(dent)->pname.dentry = NULL; \
337 SDCARDFS_D(dent)->pname.mnt = NULL; \
338 spin_unlock(&SDCARDFS_D(dent)->lock); \
341 spin_unlock(&SDCARDFS_D(dent)->lock); \
345 SDCARDFS_DENT_FUNC(lower_path)
346 SDCARDFS_DENT_FUNC(orig_path)
348 static inline bool sbinfo_has_sdcard_magic(struct sdcardfs_sb_info *sbinfo)
350 return sbinfo && sbinfo->sb && sbinfo->sb->s_magic == SDCARDFS_SUPER_MAGIC;
353 /* grab a refererence if we aren't linking to ourself */
354 static inline void set_top(struct sdcardfs_inode_info *info, struct inode *top)
356 struct inode *old_top = NULL;
357 BUG_ON(IS_ERR_OR_NULL(top));
358 if (info->top && info->top != &info->vfs_inode) {
361 if (top != &info->vfs_inode)
367 static inline struct inode *grab_top(struct sdcardfs_inode_info *info)
369 struct inode *top = info->top;
377 static inline void release_top(struct sdcardfs_inode_info *info)
382 static inline int get_gid(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
383 struct sdcardfs_vfsmount_options *opts = mnt->data;
385 if (opts->gid == AID_SDCARD_RW) {
386 /* As an optimization, certain trusted system components only run
387 * as owner but operate across all users. Since we're now handing
388 * out the sdcard_rw GID only to trusted apps, we're okay relaxing
389 * the user boundary enforcement for the default view. The UIDs
390 * assigned to app directories are still multiuser aware. */
391 return AID_SDCARD_RW;
393 return multiuser_get_uid(info->userid, opts->gid);
396 static inline int get_mode(struct vfsmount *mnt, struct sdcardfs_inode_info *info) {
399 struct sdcardfs_vfsmount_options *opts = mnt->data;
400 int visible_mode = 0775 & ~opts->mask;
403 if (info->perm == PERM_PRE_ROOT) {
404 /* Top of multi-user view should always be visible to ensure
405 * secondary users can traverse inside. */
407 } else if (info->under_android) {
408 /* Block "other" access to Android directories, since only apps
409 * belonging to a specific user should be in there; we still
410 * leave +x open for the default view. */
411 if (opts->gid == AID_SDCARD_RW) {
412 visible_mode = visible_mode & ~0006;
414 visible_mode = visible_mode & ~0007;
417 owner_mode = info->lower_inode->i_mode & 0700;
418 filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
419 return filtered_mode;
422 static inline int has_graft_path(const struct dentry *dent)
426 spin_lock(&SDCARDFS_D(dent)->lock);
427 if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
429 spin_unlock(&SDCARDFS_D(dent)->lock);
434 static inline void sdcardfs_get_real_lower(const struct dentry *dent,
435 struct path *real_lower)
437 /* in case of a local obb dentry
438 * the orig_path should be returned
440 if(has_graft_path(dent))
441 sdcardfs_get_orig_path(dent, real_lower);
443 sdcardfs_get_lower_path(dent, real_lower);
446 static inline void sdcardfs_put_real_lower(const struct dentry *dent,
447 struct path *real_lower)
449 if(has_graft_path(dent))
450 sdcardfs_put_orig_path(dent, real_lower);
452 sdcardfs_put_lower_path(dent, real_lower);
455 extern struct mutex sdcardfs_super_list_lock;
456 extern struct list_head sdcardfs_super_list;
458 /* for packagelist.c */
459 extern appid_t get_appid(const char *app_name);
460 extern appid_t get_ext_gid(const char *app_name);
461 extern appid_t is_excluded(const char *app_name, userid_t userid);
462 extern int check_caller_access_to_name(struct inode *parent_node, const struct qstr* name);
463 extern int open_flags_to_access_mode(int open_flags);
464 extern int packagelist_init(void);
465 extern void packagelist_exit(void);
467 /* for derived_perm.c */
468 #define BY_NAME (1 << 0)
469 #define BY_USERID (1 << 1)
470 struct limit_search {
477 extern void setup_derived_state(struct inode *inode, perm_t perm, userid_t userid,
478 uid_t uid, bool under_android, struct inode *top);
479 extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
480 extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, const struct qstr *name);
481 extern void drop_recursive(struct dentry *parent);
482 extern void fixup_top_recursive(struct dentry *parent);
483 extern void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit);
485 extern void update_derived_permission_lock(struct dentry *dentry);
486 void fixup_lower_ownership(struct dentry* dentry, const char *name);
487 extern int need_graft_path(struct dentry *dentry);
488 extern int is_base_obbpath(struct dentry *dentry);
489 extern int is_obbpath_invalid(struct dentry *dentry);
490 extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
492 /* locking helpers */
493 static inline struct dentry *lock_parent(struct dentry *dentry)
495 struct dentry *dir = dget_parent(dentry);
496 mutex_lock_nested(&d_inode(dir)->i_mutex, I_MUTEX_PARENT);
500 static inline void unlock_dir(struct dentry *dir)
502 mutex_unlock(&d_inode(dir)->i_mutex);
506 static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
513 dent = kern_path_locked(path_s, &parent);
521 err = vfs_mkdir2(parent.mnt, d_inode(parent.dentry), dent, mode);
528 attrs.ia_uid = make_kuid(&init_user_ns, uid);
529 attrs.ia_gid = make_kgid(&init_user_ns, gid);
530 attrs.ia_valid = ATTR_UID | ATTR_GID;
531 mutex_lock(&d_inode(dent)->i_mutex);
532 notify_change2(parent.mnt, dent, &attrs, NULL);
533 mutex_unlock(&d_inode(dent)->i_mutex);
539 /* parent dentry locked by lookup_create */
540 mutex_unlock(&d_inode(parent.dentry)->i_mutex);
546 * Return 1, if a disk has enough free space, otherwise 0.
547 * We assume that any files can not be overwritten.
549 static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
552 struct path lower_path;
553 struct kstatfs statfs;
555 struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
557 if (sbi->options.reserved_mb) {
558 /* Get fs stat of lower filesystem. */
559 sdcardfs_get_lower_path(dentry, &lower_path);
560 err = vfs_statfs(&lower_path, &statfs);
561 sdcardfs_put_lower_path(dentry, &lower_path);
566 /* Invalid statfs informations. */
567 if (unlikely(statfs.f_bsize == 0))
570 /* if you are checking directory, set size to f_bsize. */
572 size = statfs.f_bsize;
575 avail = statfs.f_bavail * statfs.f_bsize;
577 /* not enough space */
578 if ((u64)size > avail)
582 if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
591 * Copies attrs and maintains sdcardfs managed attrs
592 * Since our permission check handles all special permissions, set those to be open
594 static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
596 dest->i_mode = (src->i_mode & S_IFMT) | S_IRWXU | S_IRWXG |
597 S_IROTH | S_IXOTH; /* 0775 */
598 dest->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(dest)->d_uid);
599 dest->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW);
600 dest->i_rdev = src->i_rdev;
601 dest->i_atime = src->i_atime;
602 dest->i_mtime = src->i_mtime;
603 dest->i_ctime = src->i_ctime;
604 dest->i_blkbits = src->i_blkbits;
605 dest->i_flags = src->i_flags;
606 set_nlink(dest, src->i_nlink);
609 static inline bool str_case_eq(const char *s1, const char *s2)
611 return !strcasecmp(s1, s2);
614 static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2)
616 return q1->len == q2->len && str_case_eq(q1->name, q2->name);
619 #define QSTR_LITERAL(string) QSTR_INIT(string, sizeof(string)-1)
621 #endif /* not _SDCARDFS_H_ */