cifsd: Fix regression in smb2_get_info

a Windows 10 client isn't able to store files from ksmbd servers due
unknown local permission problems (code 0x8007003A) if smb3 encryption
is enabled. Windows 10 is requesting for ATTRIBUTE_SECINFO (mask 0x20)
which is not yet handled by ksmbd, this leads to a invalid response.
For now we just reintroduce the old check to avoid processing of unhandled
flags until ATTRIBUTE_SECINFO is properly handled.
Signed-off-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifsd/smb2pdu.c

@@ -4791,6 +4791,24 @@ static int smb2_get_info_sec(struct ksmbd_work *work,
 	int addition_info = le32_to_cpu(req->AdditionalInformation);
 	int rc;
 
+	if (addition_info & ~(OWNER_SECINFO | GROUP_SECINFO | DACL_SECINFO)) {
+		ksmbd_debug(SMB, "Unsupported addition info: 0x%x)\n",
+			addition_info);
+
+		pntsd->revision = cpu_to_le16(1);
+		pntsd->type = cpu_to_le16(SELF_RELATIVE | DACL_PROTECTED);
+		pntsd->osidoffset = 0;
+		pntsd->gsidoffset = 0;
+		pntsd->sacloffset = 0;
+		pntsd->dacloffset = 0;
+
+		secdesclen = sizeof(struct smb_ntsd);
+		rsp->OutputBufferLength = cpu_to_le32(secdesclen);
+		inc_rfc1001_len(rsp_org, secdesclen);
+
+		return 0;
+	}
+
 	if (work->next_smb2_rcv_hdr_off) {
 		if (!HAS_FILE_ID(le64_to_cpu(req->VolatileFileId))) {
 			ksmbd_debug(SMB, "Compound request set FID = %u\n",