CIFS: Make demultiplex_thread work with SMB2 code

Now we can process SMB2 messages: check message, get message id
and wakeup awaiting routines.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 307 insertions, 0 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
new file mode 100644
index 000000000000..d4226782ec88
--- /dev/null
+++ b/fs/cifs/smb2misc.c
@@ -0,0 +1,307 @@
+/*
+ *   fs/cifs/smb2misc.c
+ *
+ *   Copyright (C) International Business Machines  Corp., 2002,2011
+ *                 Etersoft, 2012
+ *   Author(s): Steve French (sfrench@us.ibm.com)
+ *              Pavel Shilovsky (pshilovsky@samba.org) 2012
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as published
+ *   by the Free Software Foundation; either version 2.1 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This library is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser General Public License
+ *   along with this library; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+#include <linux/ctype.h>
+#include "smb2pdu.h"
+#include "cifsglob.h"
+#include "cifsproto.h"
+#include "smb2proto.h"
+#include "cifs_debug.h"
+#include "cifs_unicode.h"
+#include "smb2status.h"
+
+static int
+check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
+{
+	/*
+	 * Make sure that this really is an SMB, that it is a response,
+	 * and that the message ids match.
+	 */
+	if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
+	    (mid == hdr->MessageId)) {
+		if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
+			return 0;
+		else {
+			/* only one valid case where server sends us request */
+			if (hdr->Command == SMB2_OPLOCK_BREAK)
+				return 0;
+			else
+				cERROR(1, "Received Request not response");
+		}
+	} else { /* bad signature or mid */
+		if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
+			cERROR(1, "Bad protocol string signature header %x",
+				  *(unsigned int *) hdr->ProtocolId);
+		if (mid != hdr->MessageId)
+			cERROR(1, "Mids do not match");
+	}
+	cERROR(1, "Bad SMB detected. The Mid=%llu", hdr->MessageId);
+	return 1;
+}
+
+/*
+ *  The following table defines the expected "StructureSize" of SMB2 responses
+ *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS responses.
+ *
+ *  Note that commands are defined in smb2pdu.h in le16 but the array below is
+ *  indexed by command in host byte order
+ */
+static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
+	/* SMB2_NEGOTIATE */ __constant_cpu_to_le16(65),
+	/* SMB2_SESSION_SETUP */ __constant_cpu_to_le16(9),
+	/* SMB2_LOGOFF */ __constant_cpu_to_le16(4),
+	/* SMB2_TREE_CONNECT */ __constant_cpu_to_le16(16),
+	/* SMB2_TREE_DISCONNECT */ __constant_cpu_to_le16(4),
+	/* SMB2_CREATE */ __constant_cpu_to_le16(89),
+	/* SMB2_CLOSE */ __constant_cpu_to_le16(60),
+	/* SMB2_FLUSH */ __constant_cpu_to_le16(4),
+	/* SMB2_READ */ __constant_cpu_to_le16(17),
+	/* SMB2_WRITE */ __constant_cpu_to_le16(17),
+	/* SMB2_LOCK */ __constant_cpu_to_le16(4),
+	/* SMB2_IOCTL */ __constant_cpu_to_le16(49),
+	/* BB CHECK this ... not listed in documentation */
+	/* SMB2_CANCEL */ __constant_cpu_to_le16(0),
+	/* SMB2_ECHO */ __constant_cpu_to_le16(4),
+	/* SMB2_QUERY_DIRECTORY */ __constant_cpu_to_le16(9),
+	/* SMB2_CHANGE_NOTIFY */ __constant_cpu_to_le16(9),
+	/* SMB2_QUERY_INFO */ __constant_cpu_to_le16(9),
+	/* SMB2_SET_INFO */ __constant_cpu_to_le16(2),
+	/* BB FIXME can also be 44 for lease break */
+	/* SMB2_OPLOCK_BREAK */ __constant_cpu_to_le16(24)
+};
+
+int
+smb2_check_message(char *buf, unsigned int length)
+{
+	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
+	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
+	__u64 mid = hdr->MessageId;
+	__u32 len = get_rfc1002_length(buf);
+	__u32 clc_len;  /* calculated length */
+	int command;
+
+	/* BB disable following printk later */
+	cFYI(1, "%s length: 0x%x, smb_buf_length: 0x%x", __func__, length, len);
+
+	/*
+	 * Add function to do table lookup of StructureSize by command
+	 * ie Validate the wct via smb2_struct_sizes table above
+	 */
+
+	if (length < 2 + sizeof(struct smb2_hdr)) {
+		if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
+			pdu->StructureSize2 = 0;
+			/*
+			 * As with SMB/CIFS, on some error cases servers may
+			 * not return wct properly
+			 */
+			return 0;
+		} else {
+			cERROR(1, "Length less than SMB header size");
+		}
+		return 1;
+	}
+	if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
+		cERROR(1, "SMB length greater than maximum, mid=%lld", mid);
+		return 1;
+	}
+
+	if (check_smb2_hdr(hdr, mid))
+		return 1;
+
+	if (hdr->StructureSize != SMB2_HEADER_SIZE) {
+		cERROR(1, "Illegal structure size %d",
+			  le16_to_cpu(hdr->StructureSize));
+		return 1;
+	}
+
+	command = le16_to_cpu(hdr->Command);
+	if (command >= NUMBER_OF_SMB2_COMMANDS) {
+		cERROR(1, "Illegal SMB2 command %d", command);
+		return 1;
+	}
+
+	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
+		if (hdr->Status == 0 ||
+		    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2) {
+			/* error packets have 9 byte structure size */
+			cERROR(1, "Illegal response size %u for command %d",
+				   le16_to_cpu(pdu->StructureSize2), command);
+			return 1;
+		}
+	}
+
+	if (4 + len != length) {
+		cERROR(1, "Total length %u RFC1002 length %u mismatch mid %llu",
+			  length, 4 + len, mid);
+		return 1;
+	}
+
+	clc_len = smb2_calc_size(hdr);
+
+	if (4 + len != clc_len) {
+		cFYI(1, "Calculated size %u length %u mismatch mid %llu",
+			clc_len, 4 + len, mid);
+		if (clc_len == 4 + len + 1) /* BB FIXME (fix samba) */
+			return 0; /* BB workaround Samba 3 bug SessSetup rsp */
+		return 1;
+	}
+	return 0;
+}
+
+/*
+ * The size of the variable area depends on the offset and length fields
+ * located in different fields for various SMB2 responses. SMB2 responses
+ * with no variable length info, show an offset of zero for the offset field.
+ */
+static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
+	/* SMB2_NEGOTIATE */ true,
+	/* SMB2_SESSION_SETUP */ true,
+	/* SMB2_LOGOFF */ false,
+	/* SMB2_TREE_CONNECT */	false,
+	/* SMB2_TREE_DISCONNECT */ false,
+	/* SMB2_CREATE */ true,
+	/* SMB2_CLOSE */ false,
+	/* SMB2_FLUSH */ false,
+	/* SMB2_READ */	true,
+	/* SMB2_WRITE */ false,
+	/* SMB2_LOCK */	false,
+	/* SMB2_IOCTL */ true,
+	/* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
+	/* SMB2_ECHO */ false,
+	/* SMB2_QUERY_DIRECTORY */ true,
+	/* SMB2_CHANGE_NOTIFY */ true,
+	/* SMB2_QUERY_INFO */ true,
+	/* SMB2_SET_INFO */ false,
+	/* SMB2_OPLOCK_BREAK */ false
+};
+
+/*
+ * Returns the pointer to the beginning of the data area. Length of the data
+ * area and the offset to it (from the beginning of the smb are also returned.
+ */
+static char *
+smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
+{
+	*off = 0;
+	*len = 0;
+
+	/* error responses do not have data area */
+	if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
+	    (((struct smb2_err_rsp *)hdr)->StructureSize) ==
+						SMB2_ERROR_STRUCTURE_SIZE2)
+		return NULL;
+
+	/*
+	 * Following commands have data areas so we have to get the location
+	 * of the data buffer offset and data buffer length for the particular
+	 * command.
+	 */
+	switch (hdr->Command) {
+	case SMB2_NEGOTIATE:
+	case SMB2_SESSION_SETUP:
+	case SMB2_CREATE:
+	case SMB2_READ:
+	case SMB2_QUERY_INFO:
+	case SMB2_QUERY_DIRECTORY:
+	case SMB2_IOCTL:
+	case SMB2_CHANGE_NOTIFY:
+	default:
+		/* BB FIXME for unimplemented cases above */
+		cERROR(1, "no length check for command");
+		break;
+	}
+
+	/*
+	 * Invalid length or offset probably means data area is invalid, but
+	 * we have little choice but to ignore the data area in this case.
+	 */
+	if (*off > 4096) {
+		cERROR(1, "offset %d too large, data area ignored", *off);
+		*len = 0;
+		*off = 0;
+	} else if (*off < 0) {
+		cERROR(1, "negative offset %d to data invalid ignore data area",
+			  *off);
+		*off = 0;
+		*len = 0;
+	} else if (*len < 0) {
+		cERROR(1, "negative data length %d invalid, data area ignored",
+			  *len);
+		*len = 0;
+	} else if (*len > 128 * 1024) {
+		cERROR(1, "data area larger than 128K: %d", *len);
+		*len = 0;
+	}
+
+	/* return pointer to beginning of data area, ie offset from SMB start */
+	if ((*off != 0) && (*len != 0))
+		return hdr->ProtocolId + *off;
+	else
+		return NULL;
+}
+
+/*
+ * Calculate the size of the SMB message based on the fixed header
+ * portion, the number of word parameters and the data portion of the message.
+ */
+unsigned int
+smb2_calc_size(struct smb2_hdr *hdr)
+{
+	struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
+	int offset; /* the offset from the beginning of SMB to data area */
+	int data_length; /* the length of the variable length data area */
+	/* Structure Size has already been checked to make sure it is 64 */
+	int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
+
+	/*
+	 * StructureSize2, ie length of fixed parameter area has already
+	 * been checked to make sure it is the correct length.
+	 */
+	len += le16_to_cpu(pdu->StructureSize2);
+
+	if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
+		goto calc_size_exit;
+
+	smb2_get_data_area_len(&offset, &data_length, hdr);
+	cFYI(1, "SMB2 data length %d offset %d", data_length, offset);
+
+	if (data_length > 0) {
+		/*
+		 * Check to make sure that data area begins after fixed area,
+		 * Note that last byte of the fixed area is part of data area
+		 * for some commands, typically those with odd StructureSize,
+		 * so we must add one to the calculation (and 4 to account for
+		 * the size of the RFC1001 hdr.
+		 */
+		if (offset + 4 + 1 < len) {
+			cERROR(1, "data area offset %d overlaps SMB2 header %d",
+				  offset + 4 + 1, len);
+			data_length = 0;
+		} else {
+			len = 4 + offset + data_length;
+		}
+	}
+calc_size_exit:
+	cFYI(1, "SMB2 len %d", len);
+	return len;
+}