cifsd: Pass string length parameter to match_pattern()

When iterating through a directory, a file's name may not be
null-terminated (depending on the underlying filesystem implementation).

Modify match_pattern to take the string's length into account when matching
it against the request pattern.
Signed-off-by: Marios Makassikis <mmakassikis@freebox.fr>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifsd/misc.c

@@ -22,20 +22,22 @@
  * TODO : implement consideration about DOS_DOT, DOS_QM and DOS_STAR
  *
  * @string:	string to compare with a pattern
+ * @len:	string length
  * @pattern:	pattern string which might include wildcard '*' and '?'
  *
  * Return:	0 if pattern matched with the string, otherwise non zero value
  */
-int match_pattern(const char *str, const char *pattern)
+int match_pattern(const char *str, size_t len, const char *pattern)
 {
 	const char *s = str;
 	const char *p = pattern;
 	bool star = false;
 
-	while (*s) {
+	while (*s && len) {
 		switch (*p) {
 		case '?':
 			s++;
+			len--;
 			p++;
 			break;
 		case '*':
@@ -48,6 +50,7 @@ int match_pattern(const char *str, const char *pattern)
 		default:
 			if (tolower(*s) == tolower(*p)) {
 				s++;
+				len--;
 				p++;
 			} else {
 				if (!star)

fs/cifsd/misc.h

@@ -11,7 +11,7 @@ struct nls_table;
 struct kstat;
 struct ksmbd_file;
 
-int match_pattern(const char *str, const char *pattern);
+int match_pattern(const char *str, size_t len, const char *pattern);
 
 int ksmbd_validate_filename(char *filename);
 

fs/cifsd/smb2pdu.c

@@ -3837,7 +3837,7 @@ static int __query_dir(struct dir_context *ctx,
 		return 0;
 	if (ksmbd_share_veto_filename(priv->work->tcon->share_conf, name))
 		return 0;
-	if (!match_pattern(name, priv->search_pattern))
+	if (!match_pattern(name, namlen, priv->search_pattern))
 		return 0;
 
 	d_info->name		= name;

fs/cifsd/smb_common.c

@@ -294,7 +294,8 @@ int ksmbd_populate_dot_dotdot_entries(struct ksmbd_work *work,
 				d_info->name_len = 2;
 			}
 
-			if (!match_pattern(d_info->name, search_pattern)) {
+			if (!match_pattern(d_info->name, d_info->name_len,
+					search_pattern)) {
 				dir->dot_dotdot[i] = 1;
 				continue;
 			}