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hfsplus: fix worst-case unicode to char conversion of file names and attributes

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This is a series of 3 patches which corrects issues in HFS+ concerning
the use of non-english file names and attributes.  Names and attributes
are stored internally as UTF-16 units up to a fixed maximum size, and
convert to and from user-representation by NLS.  The code incorrectly
assume that NLS string lengths are equal to unicode lengths, which is
only true for English ascii usage.

This patch (of 3):

The HFS Plus Volume Format specification (TN1150) states that file names
are stored internally as a maximum of 255 unicode characters, as defined
by The Unicode Standard, Version 2.0 [Unicode, Inc.  ISBN
0-201-48345-9].  File names are converted by the NLS system on Linux
before presented to the user.

255 CJK characters converts to UTF-8 with 1 unicode character to up to 3
bytes, and to GB18030 with 1 unicode character to up to 4 bytes.  Thus,
trying in a UTF-8 locale to list files with names of more than 85 CJK
characters results in:

    $ ls /mnt
    ls: reading directory /mnt: File name too long

The receiving buffer to hfsplus_uni2asc() needs to be 255 x
NLS_MAX_CHARSET_SIZE bytes, not 255 bytes as the code has always been.

Similar consideration applies to attributes, which are stored internally
as a maximum of 127 UTF-16BE units.  See XNU source for an up-to-date
reference on attributes.

Strictly speaking, the maximum value of NLS_MAX_CHARSET_SIZE = 6 is not
attainable in the case of conversion to UTF-8, as going beyond 3 bytes
requires the use of surrogate pairs, i.e.  consuming two input units.

Thanks Anton Altaparmakov for reviewing an earlier version of this
change.

This patch fixes all callers of hfsplus_uni2asc(), and also enables the
use of long non-English file names in HFS+.  The getting and setting,
and general usage of long non-English attributes requires further
forthcoming work, in the following patches of this series.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Reviewed-by: Anton Altaparmakov <anton@tuxera.com>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Sougata Santra <sougata@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hin-Tak Leung 2014-06-06 14:36:21 -07:00 committed by Linus Torvalds
parent 6d6bd94f4d
commit 017f8da43e
2 changed files with 21 additions and 5 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
fs/hfsplus/dir.c
View file

@ -12,6 +12,7 @@
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/random.h>
#include <linux/nls.h>
#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
@ -127,7 +128,7 @@ static int hfsplus_readdir(struct file *file, struct dir_context *ctx)
struct inode *inode = file_inode(file);
struct super_block *sb = inode->i_sb;
int len, err;
char strbuf[HFSPLUS_MAX_STRLEN + 1];
char *strbuf;
hfsplus_cat_entry entry;
struct hfs_find_data fd;
struct hfsplus_readdir_data *rd;
@ -139,6 +140,11 @@ static int hfsplus_readdir(struct file *file, struct dir_context *ctx)
err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd);
if (err)
return err;
strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN + 1, GFP_KERNEL);
if (!strbuf) {
err = -ENOMEM;
goto out;
}
hfsplus_cat_build_key(sb, fd.search_key, inode->i_ino, NULL);
err = hfs_brec_find(&fd, hfs_find_rec_by_key);
if (err)
@ -193,7 +199,7 @@ static int hfsplus_readdir(struct file *file, struct dir_context *ctx)
hfs_bnode_read(fd.bnode, &entry, fd.entryoffset,
fd.entrylength);
type = be16_to_cpu(entry.type);
len = HFSPLUS_MAX_STRLEN;
len = NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN;
err = hfsplus_uni2asc(sb, &fd.key->cat.name, strbuf, &len);
if (err)
goto out;
@ -246,6 +252,7 @@ next:
}
memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key));
out:
kfree(strbuf);
hfs_find_exit(&fd);
return err;
}

15
fs/hfsplus/xattr.c
View file

@ -8,6 +8,7 @@
#include "hfsplus_fs.h"
#include <linux/posix_acl_xattr.h>
#include <linux/nls.h>
#include "xattr.h"
#include "acl.h"
@ -645,8 +646,7 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
struct hfs_find_data fd;
u16 key_len = 0;
struct hfsplus_attr_key attr_key;
char strbuf[HFSPLUS_ATTR_MAX_STRLEN +
XATTR_MAC_OSX_PREFIX_LEN + 1] = {0};
char *strbuf;
int xattr_name_len;
if ((!S_ISREG(inode->i_mode) &&
@ -666,6 +666,13 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
return err;
}
strbuf = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN +
XATTR_MAC_OSX_PREFIX_LEN + 1, GFP_KERNEL);
if (!strbuf) {
res = -ENOMEM;
goto out;
}
err = hfsplus_find_attr(inode->i_sb, inode->i_ino, NULL, &fd);
if (err) {
if (err == -ENOENT) {
@ -692,7 +699,7 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
if (be32_to_cpu(attr_key.cnid) != inode->i_ino)
goto end_listxattr;
xattr_name_len = HFSPLUS_ATTR_MAX_STRLEN;
xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN;
if (hfsplus_uni2asc(inode->i_sb,
(const struct hfsplus_unistr *)&fd.key->attr.key_name,
strbuf, &xattr_name_len)) {
@ -718,6 +725,8 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size)
}
end_listxattr:
kfree(strbuf);
out:
hfs_find_exit(&fd);
return res;
}