[PATCH 4.9 017/152] Reset TreeId to zero on SMB2 TREE_CONNECT

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan-Marek Glogowski <glogow@xxxxxxxxxx>

commit 806a28efe9b78ffae5e2757e1ee924b8e50c08ab upstream.

Currently the cifs module breaks the CIFS specs on reconnect as
described in http://msdn.microsoft.com/en-us/library/cc246529.aspx:

"TreeId (4 bytes): Uniquely identifies the tree connect for the
command. This MUST be 0 for the SMB2 TREE_CONNECT Request."

Signed-off-by: Jan-Marek Glogowski <glogow@xxxxxxxxxx>
Reviewed-by: Aurelien Aptel <aaptel@xxxxxxxx>
Tested-by: Aurelien Aptel <aaptel@xxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/cifs/smb2pdu.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -1104,6 +1104,10 @@ SMB2_tcon(const unsigned int xid, struct
 		return -EINVAL;
 	}
 
+	/* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
+	if (tcon)
+		tcon->tid = 0;
+
 	rc = small_smb2_init(SMB2_TREE_CONNECT, tcon, (void **) &req);
 	if (rc) {
 		kfree(unc_path);