path: root/fs/hfsplus/xattr.c
diff options
authorHin-Tak Leung <>2014-06-06 14:36:21 -0700
committerLinus Torvalds <>2014-06-06 16:08:09 -0700
commit017f8da43e92ddd9989884720b694a512e09ccce (patch)
tree2edff7cb8d45e6e859b91d8a7382799459f818f0 /fs/hfsplus/xattr.c
parent6d6bd94f4d83d70cdff67d0bf2a64ef6878216e7 (diff)
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. [ fix build] Signed-off-by: Hin-Tak Leung <> Reviewed-by: Anton Altaparmakov <> Cc: Vyacheslav Dubeyko <> Cc: Al Viro <> Cc: Christoph Hellwig <> Cc: Sougata Santra <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'fs/hfsplus/xattr.c')
1 files changed, 12 insertions, 3 deletions
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 4e27edc082a4..e2b3c9ea1c71 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -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;
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;
+ 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;
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)
+ kfree(strbuf);
return res;