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linux/fs/exfat/exfat_fs.h
Al Viro a13d1a4de3 exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper 
That stuff can be accessed by ->d_hash()/->d_compare(); as it is, we have
a hard-to-hit UAF if rcu pathwalk manages to get into ->d_hash() on a filesystem
that is in process of getting shut down.

Besides, having nls and upcase table cleanup moved from ->put_super() towards
the place where sbi is freed makes for simpler failure exits.

Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2024-02-25 02:10:31 -05:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
*/
#ifndef _EXFAT_FS_H
#define _EXFAT_FS_H
#include <linux/fs.h>
#include <linux/ratelimit.h>
#include <linux/nls.h>
#include <linux/blkdev.h>
#define EXFAT_ROOT_INO 1
#define EXFAT_CLUSTERS_UNTRACKED (~0u)
/*
* exfat error flags
*/
enum exfat_error_mode {
EXFAT_ERRORS_CONT, /* ignore error and continue */
EXFAT_ERRORS_PANIC, /* panic on error */
EXFAT_ERRORS_RO, /* remount r/o on error */
};
/*
* exfat nls lossy flag
*/
enum {
NLS_NAME_NO_LOSSY = 0, /* no lossy */
NLS_NAME_LOSSY = 1 << 0, /* just detected incorrect filename(s) */
NLS_NAME_OVERLEN = 1 << 1, /* the length is over than its limit */
};
#define EXFAT_HASH_BITS 8
#define EXFAT_HASH_SIZE (1UL << EXFAT_HASH_BITS)
/*
* Type Definitions
*/
#define ES_2_ENTRIES 2
#define ES_ALL_ENTRIES 0
#define ES_IDX_FILE 0
#define ES_IDX_STREAM 1
#define ES_IDX_FIRST_FILENAME 2
#define EXFAT_FILENAME_ENTRY_NUM(name_len) \
DIV_ROUND_UP(name_len, EXFAT_FILE_NAME_LEN)
#define ES_IDX_LAST_FILENAME(name_len) \
(ES_IDX_FIRST_FILENAME + EXFAT_FILENAME_ENTRY_NUM(name_len) - 1)
#define DIR_DELETED 0xFFFFFFF7
/* type values */
#define TYPE_UNUSED 0x0000
#define TYPE_DELETED 0x0001
#define TYPE_INVALID 0x0002
#define TYPE_CRITICAL_PRI 0x0100
#define TYPE_BITMAP 0x0101
#define TYPE_UPCASE 0x0102
#define TYPE_VOLUME 0x0103
#define TYPE_DIR 0x0104
#define TYPE_FILE 0x011F
#define TYPE_CRITICAL_SEC 0x0200
#define TYPE_STREAM 0x0201
#define TYPE_EXTEND 0x0202
#define TYPE_ACL 0x0203
#define TYPE_BENIGN_PRI 0x0400
#define TYPE_GUID 0x0401
#define TYPE_PADDING 0x0402
#define TYPE_ACLTAB 0x0403
#define TYPE_BENIGN_SEC 0x0800
#define TYPE_VENDOR_EXT 0x0801
#define TYPE_VENDOR_ALLOC 0x0802
#define MAX_CHARSET_SIZE 6 /* max size of multi-byte character */
#define MAX_NAME_LENGTH 255 /* max len of file name excluding NULL */
#define MAX_VFSNAME_BUF_SIZE ((MAX_NAME_LENGTH + 1) * MAX_CHARSET_SIZE)
#define EXFAT_HINT_NONE -1
#define EXFAT_MIN_SUBDIR 2
/*
* helpers for cluster size to byte conversion.
*/
#define EXFAT_CLU_TO_B(b, sbi) ((b) << (sbi)->cluster_size_bits)
#define EXFAT_B_TO_CLU(b, sbi) ((b) >> (sbi)->cluster_size_bits)
#define EXFAT_B_TO_CLU_ROUND_UP(b, sbi) \
(((b - 1) >> (sbi)->cluster_size_bits) + 1)
#define EXFAT_CLU_OFFSET(off, sbi) ((off) & ((sbi)->cluster_size - 1))
/*
* helpers for block size to byte conversion.
*/
#define EXFAT_BLK_TO_B(b, sb) ((b) << (sb)->s_blocksize_bits)
#define EXFAT_B_TO_BLK(b, sb) ((b) >> (sb)->s_blocksize_bits)
#define EXFAT_B_TO_BLK_ROUND_UP(b, sb) \
(((b - 1) >> (sb)->s_blocksize_bits) + 1)
#define EXFAT_BLK_OFFSET(off, sb) ((off) & ((sb)->s_blocksize - 1))
/*
* helpers for block size to dentry size conversion.
*/
#define EXFAT_B_TO_DEN(b) ((b) >> DENTRY_SIZE_BITS)
#define EXFAT_DEN_TO_B(b) ((b) << DENTRY_SIZE_BITS)
/*
* helpers for cluster size to dentry size conversion.
*/
#define EXFAT_CLU_TO_DEN(clu, sbi) \
((clu) << ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
#define EXFAT_DEN_TO_CLU(dentry, sbi) \
((dentry) >> ((sbi)->cluster_size_bits - DENTRY_SIZE_BITS))
/*
* helpers for fat entry.
*/
#define FAT_ENT_SIZE (4)
#define FAT_ENT_SIZE_BITS (2)
#define FAT_ENT_OFFSET_SECTOR(sb, loc) (EXFAT_SB(sb)->FAT1_start_sector + \
(((u64)loc << FAT_ENT_SIZE_BITS) >> sb->s_blocksize_bits))
#define FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc) \
((loc << FAT_ENT_SIZE_BITS) & (sb->s_blocksize - 1))
/*
* helpers for bitmap.
*/
#define CLUSTER_TO_BITMAP_ENT(clu) ((clu) - EXFAT_RESERVED_CLUSTERS)
#define BITMAP_ENT_TO_CLUSTER(ent) ((ent) + EXFAT_RESERVED_CLUSTERS)
#define BITS_PER_SECTOR(sb) ((sb)->s_blocksize * BITS_PER_BYTE)
#define BITS_PER_SECTOR_MASK(sb) (BITS_PER_SECTOR(sb) - 1)
#define BITMAP_OFFSET_SECTOR_INDEX(sb, ent) \
((ent / BITS_PER_BYTE) >> (sb)->s_blocksize_bits)
#define BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent) (ent & BITS_PER_SECTOR_MASK(sb))
#define BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent) \
((ent / BITS_PER_BYTE) & ((sb)->s_blocksize - 1))
#define IGNORED_BITS_REMAINED(clu, clu_base) ((1UL << ((clu) - (clu_base))) - 1)
#define ES_ENTRY_NUM(name_len) (ES_IDX_LAST_FILENAME(name_len) + 1)
/* 19 entries = 1 file entry + 1 stream entry + 17 filename entries */
#define ES_MAX_ENTRY_NUM ES_ENTRY_NUM(MAX_NAME_LENGTH)
/*
* 19 entries x 32 bytes/entry = 608 bytes.
* The 608 bytes are in 3 sectors at most (even 512 Byte sector).
*/
#define DIR_CACHE_SIZE \
(DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1)
struct exfat_dentry_namebuf {
char *lfn;
int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */
};
/* unicode name structure */
struct exfat_uni_name {
/* +3 for null and for converting */
unsigned short name[MAX_NAME_LENGTH + 3];
u16 name_hash;
unsigned char name_len;
};
/* directory structure */
struct exfat_chain {
unsigned int dir;
unsigned int size;
unsigned char flags;
};
/* first empty entry hint information */
struct exfat_hint_femp {
/* entry index of a directory */
int eidx;
/* count of continuous empty entry */
int count;
/* the cluster that first empty slot exists in */
struct exfat_chain cur;
};
/* hint structure */
struct exfat_hint {
unsigned int clu;
union {
unsigned int off; /* cluster offset */
int eidx; /* entry index */
};
};
struct exfat_entry_set_cache {
struct super_block *sb;
unsigned int start_off;
int num_bh;
struct buffer_head *__bh[DIR_CACHE_SIZE];
struct buffer_head **bh;
unsigned int num_entries;
bool modified;
};
#define IS_DYNAMIC_ES(es) ((es)->__bh != (es)->bh)
struct exfat_dir_entry {
struct exfat_chain dir;
int entry;
unsigned int type;
unsigned int start_clu;
unsigned char flags;
unsigned short attr;
loff_t size;
loff_t valid_size;
unsigned int num_subdirs;
struct timespec64 atime;
struct timespec64 mtime;
struct timespec64 crtime;
struct exfat_dentry_namebuf namebuf;
};
/*
* exfat mount in-memory data
*/
struct exfat_mount_options {
kuid_t fs_uid;
kgid_t fs_gid;
unsigned short fs_fmask;
unsigned short fs_dmask;
/* permission for setting the [am]time */
unsigned short allow_utime;
/* charset for filename input/display */
char *iocharset;
/* on error: continue, panic, remount-ro */
enum exfat_error_mode errors;
unsigned utf8:1, /* Use of UTF-8 character set */
sys_tz:1, /* Use local timezone */
discard:1, /* Issue discard requests on deletions */
keep_last_dots:1; /* Keep trailing periods in paths */
int time_offset; /* Offset of timestamps from UTC (in minutes) */
/* Support creating zero-size directory, default: false */
bool zero_size_dir;
};
/*
* EXFAT file system superblock in-memory data
*/
struct exfat_sb_info {
unsigned long long num_sectors; /* num of sectors in volume */
unsigned int num_clusters; /* num of clusters in volume */
unsigned int cluster_size; /* cluster size in bytes */
unsigned int cluster_size_bits;
unsigned int sect_per_clus; /* cluster size in sectors */
unsigned int sect_per_clus_bits;
unsigned long long FAT1_start_sector; /* FAT1 start sector */
unsigned long long FAT2_start_sector; /* FAT2 start sector */
unsigned long long data_start_sector; /* data area start sector */
unsigned int num_FAT_sectors; /* num of FAT sectors */
unsigned int root_dir; /* root dir cluster */
unsigned int dentries_per_clu; /* num of dentries per cluster */
unsigned int vol_flags; /* volume flags */
unsigned int vol_flags_persistent; /* volume flags to retain */
struct buffer_head *boot_bh; /* buffer_head of BOOT sector */
unsigned int map_clu; /* allocation bitmap start cluster */
unsigned int map_sectors; /* num of allocation bitmap sectors */
struct buffer_head **vol_amap; /* allocation bitmap */
unsigned short *vol_utbl; /* upcase table */
unsigned int clu_srch_ptr; /* cluster search pointer */
unsigned int used_clusters; /* number of used clusters */
struct mutex s_lock; /* superblock lock */
struct mutex bitmap_lock; /* bitmap lock */
struct exfat_mount_options options;
struct nls_table *nls_io; /* Charset used for input and display */
struct ratelimit_state ratelimit;
spinlock_t inode_hash_lock;
struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
struct rcu_head rcu;
};
#define EXFAT_CACHE_VALID 0
/*
* EXFAT file system inode in-memory data
*/
struct exfat_inode_info {
struct exfat_chain dir;
int entry;
unsigned int type;
unsigned short attr;
unsigned int start_clu;
unsigned char flags;
/*
* the copy of low 32bit of i_version to check
* the validation of hint_stat.
*/
unsigned int version;
/* hint for cluster last accessed */
struct exfat_hint hint_bmap;
/* hint for entry index we try to lookup next time */
struct exfat_hint hint_stat;
/* hint for first empty entry */
struct exfat_hint_femp hint_femp;
spinlock_t cache_lru_lock;
struct list_head cache_lru;
int nr_caches;
/* for avoiding the race between alloc and free */
unsigned int cache_valid_id;
/*
* NOTE: i_size_ondisk is 64bits, so must hold ->inode_lock to access.
* physically allocated size.
*/
loff_t i_size_ondisk;
/* block-aligned i_size (used in cont_write_begin) */
loff_t i_size_aligned;
/* on-disk position of directory entry or 0 */
loff_t i_pos;
loff_t valid_size;
/* hash by i_location */
struct hlist_node i_hash_fat;
/* protect bmap against truncate */
struct rw_semaphore truncate_lock;
struct inode vfs_inode;
/* File creation time */
struct timespec64 i_crtime;
};
static inline struct exfat_sb_info *EXFAT_SB(struct super_block *sb)
{
return sb->s_fs_info;
}
static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
{
return container_of(inode, struct exfat_inode_info, vfs_inode);
}
/*
* If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to
* save ATTR_RO instead of ->i_mode.
*
* If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
* bit, it's just used as flag for app.
*/
static inline int exfat_mode_can_hold_ro(struct inode *inode)
{
struct exfat_sb_info *sbi = EXFAT_SB(inode->i_sb);
if (S_ISDIR(inode->i_mode))
return 0;
if ((~sbi->options.fs_fmask) & 0222)
return 1;
return 0;
}
/* Convert attribute bits and a mask to the UNIX mode. */
static inline mode_t exfat_make_mode(struct exfat_sb_info *sbi,
unsigned short attr, mode_t mode)
{
if ((attr & EXFAT_ATTR_READONLY) && !(attr & EXFAT_ATTR_SUBDIR))
mode &= ~0222;
if (attr & EXFAT_ATTR_SUBDIR)
return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
return (mode & ~sbi->options.fs_fmask) | S_IFREG;
}
/* Return the FAT attribute byte for this inode */
static inline unsigned short exfat_make_attr(struct inode *inode)
{
unsigned short attr = EXFAT_I(inode)->attr;
if (S_ISDIR(inode->i_mode))
attr |= EXFAT_ATTR_SUBDIR;
if (exfat_mode_can_hold_ro(inode) && !(inode->i_mode & 0222))
attr |= EXFAT_ATTR_READONLY;
return attr;
}
static inline void exfat_save_attr(struct inode *inode, unsigned short attr)
{
if (exfat_mode_can_hold_ro(inode))
EXFAT_I(inode)->attr = attr & (EXFAT_ATTR_RWMASK | EXFAT_ATTR_READONLY);
else
EXFAT_I(inode)->attr = attr & EXFAT_ATTR_RWMASK;
}
static inline bool exfat_is_last_sector_in_cluster(struct exfat_sb_info *sbi,
sector_t sec)
{
return ((sec - sbi->data_start_sector + 1) &
((1 << sbi->sect_per_clus_bits) - 1)) == 0;
}
static inline sector_t exfat_cluster_to_sector(struct exfat_sb_info *sbi,
unsigned int clus)
{
return ((sector_t)(clus - EXFAT_RESERVED_CLUSTERS) << sbi->sect_per_clus_bits) +
sbi->data_start_sector;
}
static inline unsigned int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
sector_t sec)
{
return ((sec - sbi->data_start_sector) >> sbi->sect_per_clus_bits) +
EXFAT_RESERVED_CLUSTERS;
}
static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
unsigned int clus)
{
return clus >= EXFAT_FIRST_CLUSTER && clus < sbi->num_clusters;
}
/* super.c */
int exfat_set_volume_dirty(struct super_block *sb);
int exfat_clear_volume_dirty(struct super_block *sb);
/* fatent.c */
#define exfat_get_next_cluster(sb, pclu) exfat_ent_get(sb, *(pclu), pclu)
int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
struct exfat_chain *p_chain, bool sync_bmap);
int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain);
int exfat_ent_get(struct super_block *sb, unsigned int loc,
unsigned int *content);
int exfat_ent_set(struct super_block *sb, unsigned int loc,
unsigned int content);
int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
int entry, struct exfat_dentry *p_entry);
int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain,
unsigned int len);
int exfat_zeroed_cluster(struct inode *dir, unsigned int clu);
int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain,
unsigned int *ret_clu);
int exfat_count_num_clusters(struct super_block *sb,
struct exfat_chain *p_chain, unsigned int *ret_count);
/* balloc.c */
int exfat_load_bitmap(struct super_block *sb);
void exfat_free_bitmap(struct exfat_sb_info *sbi);
int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync);
void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync);
unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu);
int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count);
int exfat_trim_fs(struct inode *inode, struct fstrim_range *range);
/* file.c */
extern const struct file_operations exfat_file_operations;
int __exfat_truncate(struct inode *inode);
void exfat_truncate(struct inode *inode);
int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr);
int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, unsigned int request_mask,
unsigned int query_flags);
int exfat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
long exfat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
long exfat_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg);
/* namei.c */
extern const struct dentry_operations exfat_dentry_ops;
extern const struct dentry_operations exfat_utf8_dentry_ops;
/* cache.c */
int exfat_cache_init(void);
void exfat_cache_shutdown(void);
void exfat_cache_inval_inode(struct inode *inode);
int exfat_get_cluster(struct inode *inode, unsigned int cluster,
unsigned int *fclus, unsigned int *dclus,
unsigned int *last_dclus, int allow_eof);
/* dir.c */
extern const struct inode_operations exfat_dir_inode_operations;
extern const struct file_operations exfat_dir_operations;
unsigned int exfat_get_entry_type(struct exfat_dentry *p_entry);
int exfat_init_dir_entry(struct inode *inode, struct exfat_chain *p_dir,
int entry, unsigned int type, unsigned int start_clu,
unsigned long long size);
int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
int entry, int num_entries, struct exfat_uni_name *p_uniname);
int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
int entry, int order, int num_entries);
int exfat_update_dir_chksum(struct inode *inode, struct exfat_chain *p_dir,
int entry);
void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es);
int exfat_calc_num_entries(struct exfat_uni_name *p_uniname);
int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
struct exfat_chain *p_dir, struct exfat_uni_name *p_uniname,
struct exfat_hint *hint_opt);
int exfat_alloc_new_dir(struct inode *inode, struct exfat_chain *clu);
struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
struct exfat_chain *p_dir, int entry, struct buffer_head **bh);
struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
int num);
int exfat_get_dentry_set(struct exfat_entry_set_cache *es,
struct super_block *sb, struct exfat_chain *p_dir, int entry,
unsigned int type);
int exfat_put_dentry_set(struct exfat_entry_set_cache *es, int sync);
int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
/* inode.c */
extern const struct inode_operations exfat_file_inode_operations;
void exfat_sync_inode(struct inode *inode);
struct inode *exfat_build_inode(struct super_block *sb,
struct exfat_dir_entry *info, loff_t i_pos);
void exfat_hash_inode(struct inode *inode, loff_t i_pos);
void exfat_unhash_inode(struct inode *inode);
struct inode *exfat_iget(struct super_block *sb, loff_t i_pos);
int __exfat_write_inode(struct inode *inode, int sync);
int exfat_write_inode(struct inode *inode, struct writeback_control *wbc);
void exfat_evict_inode(struct inode *inode);
int exfat_block_truncate_page(struct inode *inode, loff_t from);
/* exfat/nls.c */
unsigned short exfat_toupper(struct super_block *sb, unsigned short a);
int exfat_uniname_ncmp(struct super_block *sb, unsigned short *a,
unsigned short *b, unsigned int len);
int exfat_utf16_to_nls(struct super_block *sb,
struct exfat_uni_name *uniname, unsigned char *p_cstring,
int len);
int exfat_nls_to_utf16(struct super_block *sb,
const unsigned char *p_cstring, const int len,
struct exfat_uni_name *uniname, int *p_lossy);
int exfat_create_upcase_table(struct super_block *sb);
void exfat_free_upcase_table(struct exfat_sb_info *sbi);
/* exfat/misc.c */
void __exfat_fs_error(struct super_block *sb, int report, const char *fmt, ...)
__printf(3, 4) __cold;
#define exfat_fs_error(sb, fmt, args...) \
__exfat_fs_error(sb, 1, fmt, ## args)
#define exfat_fs_error_ratelimit(sb, fmt, args...) \
__exfat_fs_error(sb, __ratelimit(&EXFAT_SB(sb)->ratelimit), \
fmt, ## args)
/* expand to pr_*() with prefix */
#define exfat_err(sb, fmt, ...) \
pr_err("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
#define exfat_warn(sb, fmt, ...) \
pr_warn("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
#define exfat_info(sb, fmt, ...) \
pr_info("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
#define exfat_debug(sb, fmt, ...) \
pr_debug("exFAT-fs (%s): " fmt "\n", (sb)->s_id, ##__VA_ARGS__)
void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
u8 tz, __le16 time, __le16 date, u8 time_cs);
void exfat_truncate_atime(struct timespec64 *ts);
void exfat_truncate_inode_atime(struct inode *inode);
void exfat_set_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
u8 *tz, __le16 *time, __le16 *date, u8 *time_cs);
u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type);
u32 exfat_calc_chksum32(void *data, int len, u32 chksum, int type);
void exfat_update_bh(struct buffer_head *bh, int sync);
int exfat_update_bhs(struct buffer_head **bhs, int nr_bhs, int sync);
void exfat_chain_set(struct exfat_chain *ec, unsigned int dir,
unsigned int size, unsigned char flags);
void exfat_chain_dup(struct exfat_chain *dup, struct exfat_chain *ec);
#endif /* !_EXFAT_FS_H */
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