SMB2 FSCTL and IOCTL worker function

This worker function is needed to send SMB2 fsctl
(and ioctl) requests including:

validating negotiation info (secure negotiate)
querying the servers network interfaces
copy offload (refcopy)

Followon patches for the above three will use this.
This patch also does general validation of the response.

In the future, as David Disseldorp notes, for the copychunk ioctl
case, we will want to enhance the response processing to allow
returning the chunk request limits to the caller (even
though the server returns an error, in that case we would
return data that the caller could use - see 2.2.32.1).

See MS-SMB2 Section 2.2.31 for more details on format of fsctl.
Acked-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/smb2misc.c

@@ -266,6 +266,10 @@ smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
 		  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferLength);
 		break;
 	case SMB2_IOCTL:
+		*off = le32_to_cpu(
+		  ((struct smb2_ioctl_rsp *)hdr)->OutputOffset);
+		*len = le32_to_cpu(((struct smb2_ioctl_rsp *)hdr)->OutputCount);
+		break;
 	case SMB2_CHANGE_NOTIFY:
 	default:
 		/* BB FIXME for unimplemented cases above */

fs/cifs/smb2pdu.c

@@ -997,6 +997,122 @@ SMB2_open(const unsigned int xid, struct cifs_tcon *tcon, __le16 *path,
 	return rc;
 }
 
+/*
+ *	SMB2 IOCTL is used for both IOCTLs and FSCTLs
+ */
+int
+SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
+	   u64 volatile_fid, u32 opcode, bool is_fsctl, char *in_data,
+	   u32 indatalen, char **out_data, u32 *plen /* returned data len */)
+{
+	struct smb2_ioctl_req *req;
+	struct smb2_ioctl_rsp *rsp;
+	struct TCP_Server_Info *server;
+	struct cifs_ses *ses = tcon->ses;
+	struct kvec iov[2];
+	int resp_buftype;
+	int num_iovecs;
+	int rc = 0;
+
+	cifs_dbg(FYI, "SMB2 IOCTL\n");
+
+	/* zero out returned data len, in case of error */
+	if (plen)
+		*plen = 0;
+
+	if (ses && (ses->server))
+		server = ses->server;
+	else
+		return -EIO;
+
+	rc = small_smb2_init(SMB2_IOCTL, tcon, (void **) &req);
+	if (rc)
+		return rc;
+
+	req->CtlCode = cpu_to_le32(opcode);
+	req->PersistentFileId = persistent_fid;
+	req->VolatileFileId = volatile_fid;
+
+	if (indatalen) {
+		req->InputCount = cpu_to_le32(indatalen);
+		/* do not set InputOffset if no input data */
+		req->InputOffset =
+		       cpu_to_le32(offsetof(struct smb2_ioctl_req, Buffer) - 4);
+		iov[1].iov_base = in_data;
+		iov[1].iov_len = indatalen;
+		num_iovecs = 2;
+	} else
+		num_iovecs = 1;
+
+	req->OutputOffset = 0;
+	req->OutputCount = 0; /* MBZ */
+
+	/*
+	 * Could increase MaxOutputResponse, but that would require more
+	 * than one credit. Windows typically sets this smaller, but for some
+	 * ioctls it may be useful to allow server to send more. No point
+	 * limiting what the server can send as long as fits in one credit
+	 */
+	req->MaxOutputResponse = cpu_to_le32(0xFF00); /* < 64K uses 1 credit */
+
+	if (is_fsctl)
+		req->Flags = cpu_to_le32(SMB2_0_IOCTL_IS_FSCTL);
+	else
+		req->Flags = 0;
+
+	iov[0].iov_base = (char *)req;
+	/* 4 for rfc1002 length field */
+	iov[0].iov_len = get_rfc1002_length(req) + 4;
+
+	if (indatalen)
+		inc_rfc1001_len(req, indatalen);
+
+	rc = SendReceive2(xid, ses, iov, num_iovecs, &resp_buftype, 0);
+	rsp = (struct smb2_ioctl_rsp *)iov[0].iov_base;
+
+	if (rc != 0) {
+		if (tcon)
+			cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
+		goto ioctl_exit;
+	}
+
+	/* check if caller wants to look at return data or just return rc */
+	if ((plen == NULL) || (out_data == NULL))
+		goto ioctl_exit;
+
+	*plen = le32_to_cpu(rsp->OutputCount);
+
+	/* We check for obvious errors in the output buffer length and offset */
+	if (*plen == 0)
+		goto ioctl_exit; /* server returned no data */
+	else if (*plen > 0xFF00) {
+		cifs_dbg(VFS, "srv returned invalid ioctl length: %d\n", *plen);
+		*plen = 0;
+		rc = -EIO;
+		goto ioctl_exit;
+	}
+
+	if (get_rfc1002_length(rsp) < le32_to_cpu(rsp->OutputOffset) + *plen) {
+		cifs_dbg(VFS, "Malformed ioctl resp: len %d offset %d\n", *plen,
+			le32_to_cpu(rsp->OutputOffset));
+		*plen = 0;
+		rc = -EIO;
+		goto ioctl_exit;
+	}
+
+	*out_data = kmalloc(*plen, GFP_KERNEL);
+	if (*out_data == NULL) {
+		rc = -ENOMEM;
+		goto ioctl_exit;
+	}
+
+	memcpy(*out_data, rsp->hdr.ProtocolId + le32_to_cpu(rsp->OutputOffset),
+	       *plen);
+ioctl_exit:
+	free_rsp_buf(resp_buftype, rsp);
+	return rc;
+}
+
 int
 SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 	   u64 persistent_fid, u64 volatile_fid)

fs/cifs/smb2pdu.h

@@ -497,6 +497,29 @@ struct copychunk_ioctl {
 	__u32 Reserved2;
 } __packed;
 
+/* Response and Request are the same format */
+struct validate_negotiate_info {
+	__le32 Capabilities;
+	__u8   Guid[SMB2_CLIENT_GUID_SIZE];
+	__le16 SecurityMode;
+	__le16 DialectCount;
+	__le16 Dialect[1];
+} __packed;
+
+#define RSS_CAPABLE	0x00000001
+#define RDMA_CAPABLE	0x00000002
+
+struct network_interface_info_ioctl_rsp {
+	__le32 Next; /* next interface. zero if this is last one */
+	__le32 IfIndex;
+	__le32 Capability; /* RSS or RDMA Capable */
+	__le32 Reserved;
+	__le64 LinkSpeed;
+	char	SockAddr_Storage[128];
+} __packed;
+
+#define NO_FILE_ID 0xFFFFFFFFFFFFFFFFULL /* general ioctls to srv not to file */
+
 struct smb2_ioctl_req {
 	struct smb2_hdr hdr;
 	__le16 StructureSize;	/* Must be 57 */

fs/cifs/smb2proto.h

@@ -111,6 +111,10 @@ extern int SMB2_open(const unsigned int xid, struct cifs_tcon *tcon,
 		     __u32 desired_access, __u32 create_disposition,
 		     __u32 file_attributes, __u32 create_options,
 		     __u8 *oplock, struct smb2_file_all_info *buf);
+extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
+		     u64 persistent_fid, u64 volatile_fid, u32 opcode,
+		     bool is_fsctl, char *in_data, u32 indatalen,
+		     char **out_data, u32 *plen /* returned data len */);
 extern int SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
 extern int SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon,