RE: [PATCH v2] exfat: integrates dir-entry getting and validation

From: Namjae Jeon
Date: Thu Jul 30 2020 - 02:53:33 EST

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In reply to: Tetsuhiro Kohada: "Re: [PATCH v2] exfat: integrates dir-entry getting and validation"
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> 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>
> ---
> Changes in v2
> - Change verification order
> - Verification loop start with index 2
>
> 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 573659bfbc55..09b85746e760 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))) {
As Sungjong said, I think that TYPE_NAME seems right to be validated in exfat_get_dentry_set().

> 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)
Please use two tabs.

> {
> 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;
Type check should be in this order : FILE->STREAM->NAME->{CRITICAL_SEC|BENIGN_SEC}
I think that you are missing TYPE_NAME check here.
> + 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.
This comment seems unnecessary.

> */
> 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))
> + if (!exfat_get_validated_dentry(es, 1, TYPE_STREAM))
> + goto free_es;
> + for (i = 2; i < es->num_entries; i++) {
> + if (!exfat_get_validated_dentry(es, i, TYPE_SECONDARY))
> 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 cb51d6e83199..7e07f4645696 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);
TYPE_FILE and TYPE_STREAM was already validated in exfat_get_dentry_set().
Isn't it unnecessary duplication check ?

>
> 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);
Ditto.
>
> 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);
Ditto.
>
> info->type = exfat_get_entry_type(ep);
> info->attr = le16_to_cpu(ep->dentry.file.attr);
> --
> 2.25.1

Next message: Greg Kroah-Hartman: "Re: [PATCH 2/3] driver core: Use rwsem for kill_device() serialization"
Previous message: Wang Hai: "[PATCH net] qtnfmac: Missing platform_device_unregister() on error in qtnf_core_mac_alloc()"
In reply to: Tetsuhiro Kohada: "Re: [PATCH v2] exfat: integrates dir-entry getting and validation"
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