ksmbd: casefold utf-8 share names and fix ascii lowercase conversion
strtolower() corrupts all UTF-8 share names that have a byte in the C0
(À ISO8859-1) to DE (Þ ISO8859-1) range, since the non-ASCII part of
ISO8859-1 is incompatible with UTF-8. Prevent this by checking that a
byte is in the ASCII range with isascii(), before the conversion to
lowercase with tolower(). Properly handle case-insensitivity of UTF-8
share names by casefolding them, but fallback to ASCII lowercase
conversion on failure or if CONFIG_UNICODE is not set. Refactor to move
the share name casefolding immediately after the share name extraction.
Also, make the associated constness corrections.
Signed-off-by: Atte Heikkilä <atteh.mailbox@gmail.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/ksmbd/misc.c b/fs/ksmbd/misc.c
index 364a0a4..28459b1 100644
--- a/fs/ksmbd/misc.c
+++ b/fs/ksmbd/misc.c
@@ -7,6 +7,7 @@
#include <linux/kernel.h>
#include <linux/xattr.h>
#include <linux/fs.h>
+#include <linux/unicode.h>
#include "misc.h"
#include "smb_common.h"
@@ -226,26 +227,53 @@ void ksmbd_conv_path_to_windows(char *path)
strreplace(path, '/', '\\');
}
+static char *casefold_sharename(struct unicode_map *um, const char *name)
+{
+ char *cf_name;
+ int cf_len;
+
+ cf_name = kzalloc(KSMBD_REQ_MAX_SHARE_NAME, GFP_KERNEL);
+ if (!cf_name)
+ return ERR_PTR(-ENOMEM);
+
+ if (IS_ENABLED(CONFIG_UNICODE) && um) {
+ const struct qstr q_name = {.name = name, .len = strlen(name)};
+
+ cf_len = utf8_casefold(um, &q_name, cf_name,
+ KSMBD_REQ_MAX_SHARE_NAME);
+ if (cf_len < 0)
+ goto out_ascii;
+
+ return cf_name;
+ }
+
+out_ascii:
+ cf_len = strscpy(cf_name, name, KSMBD_REQ_MAX_SHARE_NAME);
+ if (cf_len < 0) {
+ kfree(cf_name);
+ return ERR_PTR(-E2BIG);
+ }
+
+ for (; *cf_name; ++cf_name)
+ *cf_name = isascii(*cf_name) ? tolower(*cf_name) : *cf_name;
+ return cf_name - cf_len;
+}
+
/**
* ksmbd_extract_sharename() - get share name from tree connect request
* @treename: buffer containing tree name and share name
*
* Return: share name on success, otherwise error
*/
-char *ksmbd_extract_sharename(char *treename)
+char *ksmbd_extract_sharename(struct unicode_map *um, const char *treename)
{
- char *name = treename;
- char *dst;
- char *pos = strrchr(name, '\\');
+ const char *name = treename, *pos = strrchr(name, '\\');
if (pos)
name = (pos + 1);
/* caller has to free the memory */
- dst = kstrdup(name, GFP_KERNEL);
- if (!dst)
- return ERR_PTR(-ENOMEM);
- return dst;
+ return casefold_sharename(um, name);
}
/**
