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ksmbd: make utf-8 file name comparison work in __caseless_lookup()

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Case-insensitive file name lookups with __caseless_lookup() use
strncasecmp() for file name comparison. strncasecmp() assumes an
ISO8859-1-compatible encoding, which is not the case here as UTF-8
is always used. As such, use of strncasecmp() here produces correct
results only if both strings use characters in the ASCII range only.
Fix this by using utf8_strncasecmp() if CONFIG_UNICODE is set. On
failure or if CONFIG_UNICODE is not set, fallback to strncasecmp().
Also, as we are adding an include for `linux/unicode.h', include it
in `fs/ksmbd/connection.h' as well since it should be explicit there.

Signed-off-by: Atte Heikkilä <atteh.mailbox@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Atte Heikkilä 2022-09-28 00:57:21 +03:00 committed by Steve French
parent 7c88c1e0ab
commit dbab80e207
3 changed files with 20 additions and 3 deletions
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1
fs/ksmbd/connection.h
View File

@ -14,6 +14,7 @@
#include <net/request_sock.h>
#include <linux/kthread.h>
#include <linux/nls.h>
#include <linux/unicode.h>
#include "smb_common.h"
#include "ksmbd_work.h"

20
fs/ksmbd/vfs.c
View File

@ -1145,12 +1145,23 @@ static int __caseless_lookup(struct dir_context *ctx, const char *name,
unsigned int d_type)
{
struct ksmbd_readdir_data *buf;
int cmp = -EINVAL;
buf = container_of(ctx, struct ksmbd_readdir_data, ctx);
if (buf->used != namlen)
return 0;
if (!strncasecmp((char *)buf->private, name, namlen)) {
if (IS_ENABLED(CONFIG_UNICODE) && buf->um) {
const struct qstr q_buf = {.name = buf->private,
.len = buf->used};
const struct qstr q_name = {.name = name,
.len = namlen};
cmp = utf8_strncasecmp(buf->um, &q_buf, &q_name);
}
if (cmp < 0)
cmp = strncasecmp((char *)buf->private, name, namlen);
if (!cmp) {
memcpy((char *)buf->private, name, namlen);
buf->dirent_count = 1;
return -EEXIST;
@ -1166,7 +1177,8 @@ static int __caseless_lookup(struct dir_context *ctx, const char *name,
*
* Return: 0 on success, otherwise error
*/
static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, size_t namelen)
static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name,
size_t namelen, struct unicode_map *um)
{
int ret;
struct file *dfilp;
@ -1176,6 +1188,7 @@ static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name, size_t na
.private = name,
.used = namelen,
.dirent_count = 0,
.um = um,
};
dfilp = dentry_open(dir, flags, current_cred());
@ -1238,7 +1251,8 @@ int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *name,
break;
err = ksmbd_vfs_lookup_in_dir(&parent, filename,
filename_len);
filename_len,
work->conn->um);
path_put(&parent);
if (err)
goto out;

2
fs/ksmbd/vfs.h
View File

@ -12,6 +12,7 @@
#include <linux/namei.h>
#include <uapi/linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/unicode.h>
#include "smbacl.h"
#include "xattr.h"
@ -60,6 +61,7 @@ struct ksmbd_readdir_data {
unsigned int used;
unsigned int dirent_count;
unsigned int file_attr;
struct unicode_map *um;
};
/* ksmbd kstat wrapper to get valid create time when reading dir entry */