[PATCH 4.14 135/189] cifs: smb2ops: Fix listxattr() when there are no EAs

Greg Kroah-Hartman
2018-06-18T08:36:54Z

From: Paulo Alcantara <palcantara@suse.de>

[ Upstream commit ae2cd7fb478b8da707906ee1706ae1379968a8f9 ]

As per listxattr(2):

On success, a nonnegative number is returned indicating the size
of the extended attribute name list. On failure, -1 is returned
and errno is set appropriately.

In SMB1, when the server returns an empty EA list through a listxattr(),
it will correctly return 0 as there are no EAs for the given file.

However, in SMB2+, it returns -ENODATA in listxattr() which is wrong since
the request and response were sent successfully, although there's no actual
EA for the given file.

This patch fixes listxattr() for SMB2+ by returning 0 in cifs_listxattr()
when the server returns an empty list of EAs.

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/cifs/smb2ops.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -570,9 +570,15 @@ smb2_query_eas(const unsigned int xid, s

SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);

+ /*
+ * If ea_name is NULL (listxattr) and there are no EAs, return 0 as it's
+ * not an error. Otherwise, the specified ea_name was not found.
+ */
if (!rc)
rc = move_smb2_ea_to_cifs(ea_data, buf_size, smb2_data,
SMB2_MAX_EA_BUF, ea_name);
+ else if (!ea_name && rc == -ENODATA)
+ rc = 0;

kfree(smb2_data);
return rc;