hfsplus: fix worst-case unicode to char conversion of file names and attributes
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>
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index bdec665..fb07d26 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -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 @@
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 @@
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 @@
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 @@
}
memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key));
out:
+ kfree(strbuf);
hfs_find_exit(&fd);
return err;
}