From 9764c02fcbad40001fd3f63558d918e4d519bb75 Mon Sep 17 00:00:00 2001 From: Steve French Date: Sun, 17 Sep 2017 10:41:35 -0500 Subject: SMB3: Add support for multidialect negotiate (SMB2.1 and later) With the need to discourage use of less secure dialect, SMB1 (CIFS), we temporarily upgraded the dialect to SMB3 in 4.13, but since there are various servers which only support SMB2.1 (2.1 is more secure than CIFS/SMB1) but not optimal for a default dialect - add support for multidialect negotiation. cifs.ko will now request SMB2.1 or later (ie SMB2.1 or SMB3.0, SMB3.02) and the server will pick the latest most secure one it can support. In addition since we are sending multidialect negotiate, add support for secure negotiate to validate that a man in the middle didn't downgrade us. Signed-off-by: Steve French Reviewed-by: Pavel Shilovsky CC: Stable # 4.13+ --- fs/cifs/smb2pdu.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/cifs/smb2pdu.h') diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index 393ed5f4e1b6..6c9653a130c8 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -716,7 +716,7 @@ struct validate_negotiate_info_req { __u8 Guid[SMB2_CLIENT_GUID_SIZE]; __le16 SecurityMode; __le16 DialectCount; - __le16 Dialects[1]; /* dialect (someday maybe list) client asked for */ + __le16 Dialects[3]; /* BB expand this if autonegotiate > 3 dialects */ } __packed; struct validate_negotiate_info_rsp { -- cgit v1.2.3