diff options
Diffstat (limited to 'fs/sdcardfs/sdcardfs.h')
| -rw-r--r-- | fs/sdcardfs/sdcardfs.h | 663 |
1 files changed, 663 insertions, 0 deletions
diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h new file mode 100644 index 000000000000..b8624fd8b817 --- /dev/null +++ b/fs/sdcardfs/sdcardfs.h @@ -0,0 +1,663 @@ +/* + * 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; + unsigned int reserved_mb; +}; + +struct sdcardfs_vfsmount_options { + gid_t gid; + mode_t mask; +}; + +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) + /* 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(&d_inode(dir)->i_mutex, I_MUTEX_PARENT); + return dir; +} + +static inline void unlock_dir(struct dentry *dir) +{ + mutex_unlock(&d_inode(dir)->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, d_inode(parent.dentry), 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(&d_inode(dent)->i_mutex); + notify_change2(parent.mnt, dent, &attrs, NULL); + mutex_unlock(&d_inode(dent)->i_mutex); + +out_dput: + dput(dent); + +out_unlock: + /* parent dentry locked by lookup_create */ + mutex_unlock(&d_inode(parent.dentry)->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_ */ |