[RFC]PATCH] exfat: integrates dir-entry getting and validation
From: Tetsuhiro Kohada
Date: Fri Jun 26 2020 - 02:10:13 EST
Add validation for num, bh and type on getting dir-entry.
('file' and 'stream-ext' dir-entries are pre-validated to ensure success)
Renamed exfat_get_dentry_cached() to exfat_get_validated_dentry() due to
a change in functionality.
Integrate type-validation with simplified.
This will also recognize a dir-entry set that contains 'benign secondary'
dir-entries.
And, rename TYPE_EXTEND to TYPE_NAME.
Suggested-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
Signed-off-by: Tetsuhiro Kohada <kohada.t2@xxxxxxxxx>
---
fs/exfat/dir.c | 144 ++++++++++++++++++--------------------------
fs/exfat/exfat_fs.h | 15 +++--
fs/exfat/file.c | 4 +-
fs/exfat/inode.c | 6 +-
fs/exfat/namei.c | 4 +-
5 files changed, 73 insertions(+), 100 deletions(-)
diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index f4cea9a7fd02..e029e0986edc 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -33,6 +33,7 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
{
int i;
struct exfat_entry_set_cache *es;
+ struct exfat_dentry *ep;
es = exfat_get_dentry_set(sb, p_dir, entry, ES_ALL_ENTRIES);
if (!es)
@@ -44,13 +45,9 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
* Third entry : first file-name entry
* So, the index of first file-name dentry should start from 2.
*/
- for (i = 2; i < es->num_entries; i++) {
- struct exfat_dentry *ep = exfat_get_dentry_cached(es, i);
-
- /* end of name entry */
- if (exfat_get_entry_type(ep) != TYPE_EXTEND)
- break;
+ i = 2;
+ while ((ep = exfat_get_validated_dentry(es, i++, TYPE_NAME))) {
exfat_extract_uni_name(ep, uniname);
uniname += EXFAT_FILE_NAME_LEN;
}
@@ -372,7 +369,7 @@ unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
if (ep->type == EXFAT_STREAM)
return TYPE_STREAM;
if (ep->type == EXFAT_NAME)
- return TYPE_EXTEND;
+ return TYPE_NAME;
if (ep->type == EXFAT_ACL)
return TYPE_ACL;
return TYPE_CRITICAL_SEC;
@@ -388,7 +385,7 @@ static void exfat_set_entry_type(struct exfat_dentry *ep, unsigned int type)
ep->type &= EXFAT_DELETE;
} else if (type == TYPE_STREAM) {
ep->type = EXFAT_STREAM;
- } else if (type == TYPE_EXTEND) {
+ } else if (type == TYPE_NAME) {
ep->type = EXFAT_NAME;
} else if (type == TYPE_BITMAP) {
ep->type = EXFAT_BITMAP;
@@ -421,7 +418,7 @@ static void exfat_init_name_entry(struct exfat_dentry *ep,
{
int i;
- exfat_set_entry_type(ep, TYPE_EXTEND);
+ exfat_set_entry_type(ep, TYPE_NAME);
ep->dentry.name.flags = 0x0;
for (i = 0; i < EXFAT_FILE_NAME_LEN; i++) {
@@ -594,12 +591,12 @@ void exfat_update_dir_chksum_with_entry_set(struct exfat_entry_set_cache *es)
struct exfat_dentry *ep;
for (i = 0; i < es->num_entries; i++) {
- ep = exfat_get_dentry_cached(es, i);
+ ep = exfat_get_validated_dentry(es, i, TYPE_ALL);
chksum = exfat_calc_chksum16(ep, DENTRY_SIZE, chksum,
chksum_type);
chksum_type = CS_DEFAULT;
}
- ep = exfat_get_dentry_cached(es, 0);
+ ep = exfat_get_validated_dentry(es, 0, TYPE_FILE);
ep->dentry.file.checksum = cpu_to_le16(chksum);
es->modified = true;
}
@@ -741,92 +738,66 @@ struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
return (struct exfat_dentry *)((*bh)->b_data + off);
}
-enum exfat_validate_dentry_mode {
- ES_MODE_STARTED,
- ES_MODE_GET_FILE_ENTRY,
- ES_MODE_GET_STRM_ENTRY,
- ES_MODE_GET_NAME_ENTRY,
- ES_MODE_GET_CRITICAL_SEC_ENTRY,
-};
-
-static bool exfat_validate_entry(unsigned int type,
- enum exfat_validate_dentry_mode *mode)
-{
- if (type == TYPE_UNUSED || type == TYPE_DELETED)
- return false;
-
- switch (*mode) {
- case ES_MODE_STARTED:
- if (type != TYPE_FILE && type != TYPE_DIR)
- return false;
- *mode = ES_MODE_GET_FILE_ENTRY;
- return true;
- case ES_MODE_GET_FILE_ENTRY:
- if (type != TYPE_STREAM)
- return false;
- *mode = ES_MODE_GET_STRM_ENTRY;
- return true;
- case ES_MODE_GET_STRM_ENTRY:
- if (type != TYPE_EXTEND)
- return false;
- *mode = ES_MODE_GET_NAME_ENTRY;
- return true;
- case ES_MODE_GET_NAME_ENTRY:
- if (type == TYPE_STREAM)
- return false;
- if (type != TYPE_EXTEND) {
- if (!(type & TYPE_CRITICAL_SEC))
- return false;
- *mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
- }
- return true;
- case ES_MODE_GET_CRITICAL_SEC_ENTRY:
- if (type == TYPE_EXTEND || type == TYPE_STREAM)
- return false;
- if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
- return false;
- return true;
- default:
- WARN_ON_ONCE(1);
- return false;
- }
-}
-
-struct exfat_dentry *exfat_get_dentry_cached(
- struct exfat_entry_set_cache *es, int num)
+struct exfat_dentry *exfat_get_validated_dentry(struct exfat_entry_set_cache *es,
+ int num, unsigned int type)
{
int off = es->start_off + num * DENTRY_SIZE;
- struct buffer_head *bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
- char *p = bh->b_data + EXFAT_BLK_OFFSET(off, es->sb);
+ struct buffer_head *bh;
+ struct exfat_dentry *ep;
- return (struct exfat_dentry *)p;
+ if (num >= es->num_entries)
+ return NULL;
+
+ bh = es->bh[EXFAT_B_TO_BLK(off, es->sb)];
+ if (!bh)
+ return NULL;
+
+ ep = (struct exfat_dentry *)
+ (bh->b_data + EXFAT_BLK_OFFSET(off, es->sb));
+
+ switch (type) {
+ case TYPE_ALL: /* accept any */
+ break;
+ case TYPE_FILE:
+ if (ep->type != EXFAT_FILE)
+ return NULL;
+ break;
+ case TYPE_SECONDARY:
+ if (!(type & exfat_get_entry_type(ep)))
+ return NULL;
+ break;
+ default:
+ if (type != exfat_get_entry_type(ep))
+ return NULL;
+ }
+ return ep;
}
/*
* Returns a set of dentries for a file or dir.
*
- * Note It provides a direct pointer to bh->data via exfat_get_dentry_cached().
+ * Note It provides a direct pointer to bh->data via exfat_get_validated_dentry().
* User should call exfat_get_dentry_set() after setting 'modified' to apply
* changes made in this entry set to the real device.
*
* in:
* sb+p_dir+entry: indicates a file/dir
- * type: specifies how many dentries should be included.
+ * max_entries: specifies how many dentries should be included.
* return:
* pointer of entry set on success,
* NULL on failure.
+ * note:
+ * On success, guarantee the correct 'file' and 'stream-ext' dir-entries.
*/
struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
- struct exfat_chain *p_dir, int entry, unsigned int type)
+ struct exfat_chain *p_dir, int entry, int max_entries)
{
int ret, i, num_bh;
- unsigned int off, byte_offset, clu = 0;
+ unsigned int byte_offset, clu = 0;
sector_t sec;
struct exfat_sb_info *sbi = EXFAT_SB(sb);
struct exfat_entry_set_cache *es;
struct exfat_dentry *ep;
- int num_entries;
- enum exfat_validate_dentry_mode mode = ES_MODE_STARTED;
struct buffer_head *bh;
if (p_dir->dir == DIR_DELETED) {
@@ -844,13 +815,13 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
return NULL;
es->sb = sb;
es->modified = false;
+ es->num_entries = 1;
/* byte offset in cluster */
byte_offset = EXFAT_CLU_OFFSET(byte_offset, sbi);
/* byte offset in sector */
- off = EXFAT_BLK_OFFSET(byte_offset, sb);
- es->start_off = off;
+ es->start_off = EXFAT_BLK_OFFSET(byte_offset, sb);
/* sector offset in cluster */
sec = EXFAT_B_TO_BLK(byte_offset, sb);
@@ -861,15 +832,12 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
goto free_es;
es->bh[es->num_bh++] = bh;
- ep = exfat_get_dentry_cached(es, 0);
- if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+ ep = exfat_get_validated_dentry(es, 0, TYPE_FILE);
+ if (!ep)
goto free_es;
+ es->num_entries = min(ep->dentry.file.num_ext + 1, max_entries);
- num_entries = type == ES_ALL_ENTRIES ?
- ep->dentry.file.num_ext + 1 : type;
- es->num_entries = num_entries;
-
- num_bh = EXFAT_B_TO_BLK_ROUND_UP(off + num_entries * DENTRY_SIZE, sb);
+ num_bh = EXFAT_B_TO_BLK_ROUND_UP(es->start_off + es->num_entries * DENTRY_SIZE, sb);
for (i = 1; i < num_bh; i++) {
/* get the next sector */
if (exfat_is_last_sector_in_cluster(sbi, sec)) {
@@ -889,11 +857,13 @@ struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
}
/* validiate cached dentries */
- for (i = 1; i < num_entries; i++) {
- ep = exfat_get_dentry_cached(es, i);
- if (!exfat_validate_entry(exfat_get_entry_type(ep), &mode))
+ for (i = 1; i < es->num_entries; i++) {
+ if (!exfat_get_validated_dentry(es, i, TYPE_SECONDARY))
goto free_es;
}
+ if (!exfat_get_validated_dentry(es, 1, TYPE_STREAM))
+ goto free_es;
+
return es;
free_es:
@@ -1028,7 +998,7 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
}
brelse(bh);
- if (entry_type == TYPE_EXTEND) {
+ if (entry_type == TYPE_NAME) {
unsigned short entry_uniname[16], unichar;
if (step != DIRENT_STEP_NAME) {
@@ -1144,7 +1114,7 @@ int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
type = exfat_get_entry_type(ext_ep);
brelse(bh);
- if (type == TYPE_EXTEND || type == TYPE_STREAM)
+ if (type == TYPE_NAME || type == TYPE_STREAM)
count++;
else
break;
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 3aed8e22087a..93e11908d28d 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -40,7 +40,7 @@ enum {
* Type Definitions
*/
#define ES_2_ENTRIES 2
-#define ES_ALL_ENTRIES 0
+#define ES_ALL_ENTRIES 256
#define DIR_DELETED 0xFFFF0321
@@ -56,7 +56,7 @@ enum {
#define TYPE_FILE 0x011F
#define TYPE_CRITICAL_SEC 0x0200
#define TYPE_STREAM 0x0201
-#define TYPE_EXTEND 0x0202
+#define TYPE_NAME 0x0202
#define TYPE_ACL 0x0203
#define TYPE_BENIGN_PRI 0x0400
#define TYPE_GUID 0x0401
@@ -65,6 +65,9 @@ enum {
#define TYPE_BENIGN_SEC 0x0800
#define TYPE_ALL 0x0FFF
+#define TYPE_PRIMARY (TYPE_CRITICAL_PRI | TYPE_BENIGN_PRI)
+#define TYPE_SECONDARY (TYPE_CRITICAL_SEC | TYPE_BENIGN_SEC)
+
#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)
@@ -171,7 +174,7 @@ struct exfat_entry_set_cache {
unsigned int start_off;
int num_bh;
struct buffer_head *bh[DIR_CACHE_SIZE];
- unsigned int num_entries;
+ int num_entries;
};
struct exfat_dir_entry {
@@ -456,10 +459,10 @@ int exfat_find_location(struct super_block *sb, struct exfat_chain *p_dir,
struct exfat_dentry *exfat_get_dentry(struct super_block *sb,
struct exfat_chain *p_dir, int entry, struct buffer_head **bh,
sector_t *sector);
-struct exfat_dentry *exfat_get_dentry_cached(struct exfat_entry_set_cache *es,
- int num);
+struct exfat_dentry *exfat_get_validated_dentry(struct exfat_entry_set_cache *es,
+ int num, unsigned int type);
struct exfat_entry_set_cache *exfat_get_dentry_set(struct super_block *sb,
- struct exfat_chain *p_dir, int entry, unsigned int type);
+ struct exfat_chain *p_dir, int entry, int max_entries);
int exfat_free_dentry_set(struct exfat_entry_set_cache *es, int sync);
int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir);
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 6707f3eb09b5..b6b458e6f5e3 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -160,8 +160,8 @@ int __exfat_truncate(struct inode *inode, loff_t new_size)
ES_ALL_ENTRIES);
if (!es)
return -EIO;
- ep = exfat_get_dentry_cached(es, 0);
- ep2 = exfat_get_dentry_cached(es, 1);
+ ep = exfat_get_validated_dentry(es, 0, TYPE_FILE);
+ ep2 = exfat_get_validated_dentry(es, 1, TYPE_STREAM);
ts = current_time(inode);
exfat_set_entry_time(sbi, &ts,
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c
index f0160a7892a8..e7bc1ee1761a 100644
--- a/fs/exfat/inode.c
+++ b/fs/exfat/inode.c
@@ -45,8 +45,8 @@ static int __exfat_write_inode(struct inode *inode, int sync)
es = exfat_get_dentry_set(sb, &(ei->dir), ei->entry, ES_ALL_ENTRIES);
if (!es)
return -EIO;
- ep = exfat_get_dentry_cached(es, 0);
- ep2 = exfat_get_dentry_cached(es, 1);
+ ep = exfat_get_validated_dentry(es, 0, TYPE_FILE);
+ ep2 = exfat_get_validated_dentry(es, 1, TYPE_STREAM);
ep->dentry.file.attr = cpu_to_le16(exfat_make_attr(inode));
@@ -228,7 +228,7 @@ static int exfat_map_cluster(struct inode *inode, unsigned int clu_offset,
if (!es)
return -EIO;
/* get stream entry */
- ep = exfat_get_dentry_cached(es, 1);
+ ep = exfat_get_validated_dentry(es, 1, TYPE_STREAM);
/* update directory entry */
ep->dentry.stream.flags = ei->flags;
diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index 126ed3ba8f47..47fef6b75f28 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -664,8 +664,8 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
es = exfat_get_dentry_set(sb, &cdir, dentry, ES_2_ENTRIES);
if (!es)
return -EIO;
- ep = exfat_get_dentry_cached(es, 0);
- ep2 = exfat_get_dentry_cached(es, 1);
+ ep = exfat_get_validated_dentry(es, 0, TYPE_FILE);
+ ep2 = exfat_get_validated_dentry(es, 1, TYPE_STREAM);
info->type = exfat_get_entry_type(ep);
info->attr = le16_to_cpu(ep->dentry.file.attr);
--
2.25.1