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/*
* fs/sdcardfs/sdcardfs.h
*
* The sdcardfs v2.0
* This file system replaces the sdcard daemon on Android
* On version 2.0, some of the daemon functions have been ported
* to support the multi-user concepts of Android 4.4
*
* Copyright (c) 2013 Samsung Electronics Co. Ltd
* Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun,
* Sunghwan Yun, Sungjong Seo
*
* This program has been developed as a stackable file system based on
* the WrapFS which written by
*
* Copyright (c) 1998-2011 Erez Zadok
* Copyright (c) 2009 Shrikar Archak
* Copyright (c) 2003-2011 Stony Brook University
* Copyright (c) 2003-2011 The Research Foundation of SUNY
*
* This file is dual licensed. It may be redistributed and/or modified
* under the terms of the Apache 2.0 License OR version 2 of the GNU
* General Public License.
*/
#ifndef _SDCARDFS_H_
#define _SDCARDFS_H_
#include <linux/dcache.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/aio.h>
#include <linux/kref.h>
#include <linux/mm.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/seq_file.h>
#include <linux/statfs.h>
#include <linux/fs_stack.h>
#include <linux/magic.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/security.h>
#include <linux/string.h>
#include <linux/list.h>
#include "multiuser.h"
/* the file system name */
#define SDCARDFS_NAME "sdcardfs"
/* sdcardfs root inode number */
#define SDCARDFS_ROOT_INO 1
/* useful for tracking code reachability */
#define UDBG pr_default("DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
#define SDCARDFS_DIRENT_SIZE 256
/* temporary static uid settings for development */
#define AID_ROOT 0 /* uid for accessing /mnt/sdcard & extSdcard */
#define AID_MEDIA_RW 1023 /* internal media storage write access */
#define AID_SDCARD_RW 1015 /* external storage write access */
#define AID_SDCARD_R 1028 /* external storage read access */
#define AID_SDCARD_PICS 1033 /* external storage photos access */
#define AID_SDCARD_AV 1034 /* external storage audio/video access */
#define AID_SDCARD_ALL 1035 /* access all users external storage */
#define AID_MEDIA_OBB 1059 /* obb files */
#define AID_SDCARD_IMAGE 1057
#define AID_PACKAGE_INFO 1027
/*
* Permissions are handled by our permission function.
* We don't want anyone who happens to look at our inode value to prematurely
* block access, so store more permissive values. These are probably never
* used.
*/
#define fixup_tmp_permissions(x) \
do { \
(x)->i_uid = make_kuid(&init_user_ns, \
SDCARDFS_I(x)->data->d_uid); \
(x)->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW); \
(x)->i_mode = ((x)->i_mode & S_IFMT) | 0775;\
} while (0)
/* OVERRIDE_CRED() and REVERT_CRED()
* OVERRIDE_CRED()
* backup original task->cred
* and modifies task->cred->fsuid/fsgid to specified value.
* REVERT_CRED()
* restore original task->cred->fsuid/fsgid.
* These two macro should be used in pair, and OVERRIDE_CRED() should be
* placed at the beginning of a function, right after variable declaration.
*/
#define OVERRIDE_CRED(sdcardfs_sbi, saved_cred, info) \
do { \
saved_cred = override_fsids(sdcardfs_sbi, info->data); \
if (!saved_cred) \
return -ENOMEM; \
} while (0)
#define OVERRIDE_CRED_PTR(sdcardfs_sbi, saved_cred, info) \
do { \
saved_cred = override_fsids(sdcardfs_sbi, info->data); \
if (!saved_cred) \
return ERR_PTR(-ENOMEM); \
} while (0)
#define REVERT_CRED(saved_cred) revert_fsids(saved_cred)
/* Android 5.0 support */
/* Permission mode for a specific node. Controls how file permissions
* are derived for children nodes.
*/
typedef enum {
/* Nothing special; this node should just inherit from its parent. */
PERM_INHERIT,
/* This node is one level above a normal root; used for legacy layouts
* which use the first level to represent user_id.
*/
PERM_PRE_ROOT,
/* This node is "/" */
PERM_ROOT,
/* This node is "/Android" */
PERM_ANDROID,
/* This node is "/Android/data" */
PERM_ANDROID_DATA,
/* This node is "/Android/obb" */
PERM_ANDROID_OBB,
/* This node is "/Android/media" */
PERM_ANDROID_MEDIA,
/* This node is "/Android/[data|media|obb]/[package]" */
PERM_ANDROID_PACKAGE,
/* This node is "/Android/[data|media|obb]/[package]/cache" */
PERM_ANDROID_PACKAGE_CACHE,
} perm_t;
struct sdcardfs_sb_info;
struct sdcardfs_mount_options;
struct sdcardfs_inode_info;
struct sdcardfs_inode_data;
/* Do not directly use this function. Use OVERRIDE_CRED() instead. */
const struct cred *override_fsids(struct sdcardfs_sb_info *sbi,
struct sdcardfs_inode_data *data);
/* Do not directly use this function, use REVERT_CRED() instead. */
void revert_fsids(const struct cred *old_cred);
/* operations vectors defined in specific files */
extern const struct file_operations sdcardfs_main_fops;
extern const struct file_operations sdcardfs_dir_fops;
extern const struct inode_operations sdcardfs_main_iops;
extern const struct inode_operations sdcardfs_dir_iops;
extern const struct inode_operations sdcardfs_symlink_iops;
extern const struct super_operations sdcardfs_sops;
extern const struct dentry_operations sdcardfs_ci_dops;
extern const struct address_space_operations sdcardfs_aops, sdcardfs_dummy_aops;
extern const struct vm_operations_struct sdcardfs_vm_ops;
extern int sdcardfs_init_inode_cache(void);
extern void sdcardfs_destroy_inode_cache(void);
extern int sdcardfs_init_dentry_cache(void);
extern void sdcardfs_destroy_dentry_cache(void);
extern int new_dentry_private_data(struct dentry *dentry);
extern void free_dentry_private_data(struct dentry *dentry);
extern struct dentry *sdcardfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
extern struct inode *sdcardfs_iget(struct super_block *sb,
struct inode *lower_inode, userid_t id);
extern int sdcardfs_interpose(struct dentry *dentry, struct super_block *sb,
struct path *lower_path, userid_t id);
/* file private data */
struct sdcardfs_file_info {
struct file *lower_file;
const struct vm_operations_struct *lower_vm_ops;
};
struct sdcardfs_inode_data {
struct kref refcount;
bool abandoned;
perm_t perm;
userid_t userid;
uid_t d_uid;
bool under_android;
bool under_cache;
bool under_obb;
};
/* sdcardfs inode data in memory */
struct sdcardfs_inode_info {
struct inode *lower_inode;
/* state derived based on current position in hierarchy */
struct sdcardfs_inode_data *data;
/* top folder for ownership */
struct sdcardfs_inode_data *top_data;
struct inode vfs_inode;
};
/* sdcardfs dentry data in memory */
struct sdcardfs_dentry_info {
spinlock_t lock; /* protects lower_path */
struct path lower_path;
struct path orig_path;
};
struct sdcardfs_mount_options {
uid_t fs_low_uid;
gid_t fs_low_gid;
userid_t fs_user_id;
bool multiuser;
bool gid_derivation;
unsigned int reserved_mb;
};
struct sdcardfs_vfsmount_options {
gid_t gid;
mode_t mask;
bool default_normal;
};
extern int parse_options_remount(struct super_block *sb, char *options, int silent,
struct sdcardfs_vfsmount_options *vfsopts);
/* sdcardfs super-block data in memory */
struct sdcardfs_sb_info {
struct super_block *sb;
struct super_block *lower_sb;
/* derived perm policy : some of options have been added
* to sdcardfs_mount_options (Android 4.4 support)
*/
struct sdcardfs_mount_options options;
spinlock_t lock; /* protects obbpath */
char *obbpath_s;
struct path obbpath;
void *pkgl_id;
struct list_head list;
};
/*
* inode to private data
*
* Since we use containers and the struct inode is _inside_ the
* sdcardfs_inode_info structure, SDCARDFS_I will always (given a non-NULL
* inode pointer), return a valid non-NULL pointer.
*/
static inline struct sdcardfs_inode_info *SDCARDFS_I(const struct inode *inode)
{
return container_of(inode, struct sdcardfs_inode_info, vfs_inode);
}
/* dentry to private data */
#define SDCARDFS_D(dent) ((struct sdcardfs_dentry_info *)(dent)->d_fsdata)
/* superblock to private data */
#define SDCARDFS_SB(super) ((struct sdcardfs_sb_info *)(super)->s_fs_info)
/* file to private Data */
#define SDCARDFS_F(file) ((struct sdcardfs_file_info *)((file)->private_data))
/* file to lower file */
static inline struct file *sdcardfs_lower_file(const struct file *f)
{
return SDCARDFS_F(f)->lower_file;
}
static inline void sdcardfs_set_lower_file(struct file *f, struct file *val)
{
SDCARDFS_F(f)->lower_file = val;
}
/* inode to lower inode. */
static inline struct inode *sdcardfs_lower_inode(const struct inode *i)
{
return SDCARDFS_I(i)->lower_inode;
}
static inline void sdcardfs_set_lower_inode(struct inode *i, struct inode *val)
{
SDCARDFS_I(i)->lower_inode = val;
}
/* superblock to lower superblock */
static inline struct super_block *sdcardfs_lower_super(
const struct super_block *sb)
{
return SDCARDFS_SB(sb)->lower_sb;
}
static inline void sdcardfs_set_lower_super(struct super_block *sb,
struct super_block *val)
{
SDCARDFS_SB(sb)->lower_sb = val;
}
/* path based (dentry/mnt) macros */
static inline void pathcpy(struct path *dst, const struct path *src)
{
dst->dentry = src->dentry;
dst->mnt = src->mnt;
}
/* sdcardfs_get_pname functions calls path_get()
* therefore, the caller must call "proper" path_put functions
*/
#define SDCARDFS_DENT_FUNC(pname) \
static inline void sdcardfs_get_##pname(const struct dentry *dent, \
struct path *pname) \
{ \
spin_lock(&SDCARDFS_D(dent)->lock); \
pathcpy(pname, &SDCARDFS_D(dent)->pname); \
path_get(pname); \
spin_unlock(&SDCARDFS_D(dent)->lock); \
return; \
} \
static inline void sdcardfs_put_##pname(const struct dentry *dent, \
struct path *pname) \
{ \
path_put(pname); \
return; \
} \
static inline void sdcardfs_set_##pname(const struct dentry *dent, \
struct path *pname) \
{ \
spin_lock(&SDCARDFS_D(dent)->lock); \
pathcpy(&SDCARDFS_D(dent)->pname, pname); \
spin_unlock(&SDCARDFS_D(dent)->lock); \
return; \
} \
static inline void sdcardfs_reset_##pname(const struct dentry *dent) \
{ \
spin_lock(&SDCARDFS_D(dent)->lock); \
SDCARDFS_D(dent)->pname.dentry = NULL; \
SDCARDFS_D(dent)->pname.mnt = NULL; \
spin_unlock(&SDCARDFS_D(dent)->lock); \
return; \
} \
static inline void sdcardfs_put_reset_##pname(const struct dentry *dent) \
{ \
struct path pname; \
spin_lock(&SDCARDFS_D(dent)->lock); \
if (SDCARDFS_D(dent)->pname.dentry) { \
pathcpy(&pname, &SDCARDFS_D(dent)->pname); \
SDCARDFS_D(dent)->pname.dentry = NULL; \
SDCARDFS_D(dent)->pname.mnt = NULL; \
spin_unlock(&SDCARDFS_D(dent)->lock); \
path_put(&pname); \
} else \
spin_unlock(&SDCARDFS_D(dent)->lock); \
return; \
}
SDCARDFS_DENT_FUNC(lower_path)
SDCARDFS_DENT_FUNC(orig_path)
static inline bool sbinfo_has_sdcard_magic(struct sdcardfs_sb_info *sbinfo)
{
return sbinfo && sbinfo->sb
&& sbinfo->sb->s_magic == SDCARDFS_SUPER_MAGIC;
}
static inline struct sdcardfs_inode_data *data_get(
struct sdcardfs_inode_data *data)
{
if (data)
kref_get(&data->refcount);
return data;
}
static inline struct sdcardfs_inode_data *top_data_get(
struct sdcardfs_inode_info *info)
{
return data_get(info->top_data);
}
extern void data_release(struct kref *ref);
static inline void data_put(struct sdcardfs_inode_data *data)
{
kref_put(&data->refcount, data_release);
}
static inline void release_own_data(struct sdcardfs_inode_info *info)
{
/*
* This happens exactly once per inode. At this point, the inode that
* originally held this data is about to be freed, and all references
* to it are held as a top value, and will likely be released soon.
*/
info->data->abandoned = true;
data_put(info->data);
}
static inline void set_top(struct sdcardfs_inode_info *info,
struct sdcardfs_inode_data *top)
{
struct sdcardfs_inode_data *old_top = info->top_data;
if (top)
data_get(top);
info->top_data = top;
if (old_top)
data_put(old_top);
}
static inline int get_gid(struct vfsmount *mnt,
struct sdcardfs_inode_data *data)
{
struct sdcardfs_vfsmount_options *opts = mnt->data;
if (opts->gid == AID_SDCARD_RW && !opts->default_normal)
/* As an optimization, certain trusted system components only run
* as owner but operate across all users. Since we're now handing
* out the sdcard_rw GID only to trusted apps, we're okay relaxing
* the user boundary enforcement for the default view. The UIDs
* assigned to app directories are still multiuser aware.
*/
return AID_SDCARD_RW;
else
return multiuser_get_uid(data->userid, opts->gid);
}
static inline int get_mode(struct vfsmount *mnt,
struct sdcardfs_inode_info *info,
struct sdcardfs_inode_data *data)
{
int owner_mode;
int filtered_mode;
struct sdcardfs_vfsmount_options *opts = mnt->data;
int visible_mode = 0775 & ~opts->mask;
if (data->perm == PERM_PRE_ROOT) {
/* Top of multi-user view should always be visible to ensure
* secondary users can traverse inside.
*/
visible_mode = 0711;
} else if (data->under_android) {
/* Block "other" access to Android directories, since only apps
* belonging to a specific user should be in there; we still
* leave +x open for the default view.
*/
if (opts->gid == AID_SDCARD_RW)
visible_mode = visible_mode & ~0006;
else
visible_mode = visible_mode & ~0007;
}
owner_mode = info->lower_inode->i_mode & 0700;
filtered_mode = visible_mode & (owner_mode | (owner_mode >> 3) | (owner_mode >> 6));
return filtered_mode;
}
static inline int has_graft_path(const struct dentry *dent)
{
int ret = 0;
spin_lock(&SDCARDFS_D(dent)->lock);
if (SDCARDFS_D(dent)->orig_path.dentry != NULL)
ret = 1;
spin_unlock(&SDCARDFS_D(dent)->lock);
return ret;
}
static inline void sdcardfs_get_real_lower(const struct dentry *dent,
struct path *real_lower)
{
/* in case of a local obb dentry
* the orig_path should be returned
*/
if (has_graft_path(dent))
sdcardfs_get_orig_path(dent, real_lower);
else
sdcardfs_get_lower_path(dent, real_lower);
}
static inline void sdcardfs_put_real_lower(const struct dentry *dent,
struct path *real_lower)
{
if (has_graft_path(dent))
sdcardfs_put_orig_path(dent, real_lower);
else
sdcardfs_put_lower_path(dent, real_lower);
}
extern struct mutex sdcardfs_super_list_lock;
extern struct list_head sdcardfs_super_list;
/* for packagelist.c */
extern appid_t get_appid(const char *app_name);
extern appid_t get_ext_gid(const char *app_name);
extern appid_t is_excluded(const char *app_name, userid_t userid);
extern int check_caller_access_to_name(struct inode *parent_node, const struct qstr *name);
extern int packagelist_init(void);
extern void packagelist_exit(void);
/* for derived_perm.c */
#define BY_NAME (1 << 0)
#define BY_USERID (1 << 1)
struct limit_search {
unsigned int flags;
struct qstr name;
userid_t userid;
};
extern void setup_derived_state(struct inode *inode, perm_t perm,
userid_t userid, uid_t uid, bool under_android,
struct sdcardfs_inode_data *top);
extern void get_derived_permission(struct dentry *parent, struct dentry *dentry);
extern void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, const struct qstr *name);
extern void fixup_perms_recursive(struct dentry *dentry, struct limit_search *limit);
extern void update_derived_permission_lock(struct dentry *dentry);
void fixup_lower_ownership(struct dentry *dentry, const char *name);
extern int need_graft_path(struct dentry *dentry);
extern int is_base_obbpath(struct dentry *dentry);
extern int is_obbpath_invalid(struct dentry *dentry);
extern int setup_obb_dentry(struct dentry *dentry, struct path *lower_path);
/* locking helpers */
static inline struct dentry *lock_parent(struct dentry *dentry)
{
struct dentry *dir = dget_parent(dentry);
mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
return dir;
}
static inline void unlock_dir(struct dentry *dir)
{
mutex_unlock(&dir->d_inode->i_mutex);
dput(dir);
}
static inline int prepare_dir(const char *path_s, uid_t uid, gid_t gid, mode_t mode)
{
int err;
struct dentry *dent;
struct iattr attrs;
struct path parent;
dent = kern_path_locked(path_s, &parent);
if (IS_ERR(dent)) {
err = PTR_ERR(dent);
if (err == -EEXIST)
err = 0;
goto out_unlock;
}
err = vfs_mkdir2(parent.mnt, parent.dentry->d_inode, dent, mode);
if (err) {
if (err == -EEXIST)
err = 0;
goto out_dput;
}
attrs.ia_uid = make_kuid(&init_user_ns, uid);
attrs.ia_gid = make_kgid(&init_user_ns, gid);
attrs.ia_valid = ATTR_UID | ATTR_GID;
mutex_lock(&dent->d_inode->i_mutex);
notify_change2(parent.mnt, dent, &attrs, NULL);
mutex_unlock(&dent->d_inode->i_mutex);
out_dput:
dput(dent);
out_unlock:
/* parent dentry locked by lookup_create */
mutex_unlock(&parent.dentry->d_inode->i_mutex);
path_put(&parent);
return err;
}
/*
* Return 1, if a disk has enough free space, otherwise 0.
* We assume that any files can not be overwritten.
*/
static inline int check_min_free_space(struct dentry *dentry, size_t size, int dir)
{
int err;
struct path lower_path;
struct kstatfs statfs;
u64 avail;
struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb);
if (sbi->options.reserved_mb) {
/* Get fs stat of lower filesystem. */
sdcardfs_get_lower_path(dentry, &lower_path);
err = vfs_statfs(&lower_path, &statfs);
sdcardfs_put_lower_path(dentry, &lower_path);
if (unlikely(err))
return 0;
/* Invalid statfs informations. */
if (unlikely(statfs.f_bsize == 0))
return 0;
/* if you are checking directory, set size to f_bsize. */
if (unlikely(dir))
size = statfs.f_bsize;
/* available size */
avail = statfs.f_bavail * statfs.f_bsize;
/* not enough space */
if ((u64)size > avail)
return 0;
/* enough space */
if ((avail - size) > (sbi->options.reserved_mb * 1024 * 1024))
return 1;
return 0;
} else
return 1;
}
/*
* Copies attrs and maintains sdcardfs managed attrs
* Since our permission check handles all special permissions, set those to be open
*/
static inline void sdcardfs_copy_and_fix_attrs(struct inode *dest, const struct inode *src)
{
dest->i_mode = (src->i_mode & S_IFMT) | S_IRWXU | S_IRWXG |
S_IROTH | S_IXOTH; /* 0775 */
dest->i_uid = make_kuid(&init_user_ns, SDCARDFS_I(dest)->data->d_uid);
dest->i_gid = make_kgid(&init_user_ns, AID_SDCARD_RW);
dest->i_rdev = src->i_rdev;
dest->i_atime = src->i_atime;
dest->i_mtime = src->i_mtime;
dest->i_ctime = src->i_ctime;
dest->i_blkbits = src->i_blkbits;
dest->i_flags = src->i_flags;
set_nlink(dest, src->i_nlink);
}
static inline bool str_case_eq(const char *s1, const char *s2)
{
return !strcasecmp(s1, s2);
}
static inline bool str_n_case_eq(const char *s1, const char *s2, size_t len)
{
return !strncasecmp(s1, s2, len);
}
static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2)
{
return q1->len == q2->len && str_case_eq(q1->name, q2->name);
}
/* */
#define QSTR_LITERAL(string) QSTR_INIT(string, sizeof(string)-1)
#endif /* not _SDCARDFS_H_ */