348 lines
10 KiB
C
348 lines
10 KiB
C
/*
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* fs/cifs/smb2misc.c
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*
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* Copyright (C) International Business Machines Corp., 2002,2011
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* Etersoft, 2012
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* Author(s): Steve French (sfrench@us.ibm.com)
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* Pavel Shilovsky (pshilovsky@samba.org) 2012
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published
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* by the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/ctype.h>
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#include "smb2pdu.h"
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#include "cifsglob.h"
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#include "cifsproto.h"
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#include "smb2proto.h"
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#include "cifs_debug.h"
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#include "cifs_unicode.h"
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#include "smb2status.h"
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static int
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check_smb2_hdr(struct smb2_hdr *hdr, __u64 mid)
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{
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/*
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* Make sure that this really is an SMB, that it is a response,
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* and that the message ids match.
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*/
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if ((*(__le32 *)hdr->ProtocolId == SMB2_PROTO_NUMBER) &&
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(mid == hdr->MessageId)) {
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if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
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return 0;
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else {
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/* only one valid case where server sends us request */
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if (hdr->Command == SMB2_OPLOCK_BREAK)
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return 0;
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else
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cERROR(1, "Received Request not response");
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}
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} else { /* bad signature or mid */
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if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
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cERROR(1, "Bad protocol string signature header %x",
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*(unsigned int *) hdr->ProtocolId);
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if (mid != hdr->MessageId)
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cERROR(1, "Mids do not match");
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}
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cERROR(1, "Bad SMB detected. The Mid=%llu", hdr->MessageId);
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return 1;
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}
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/*
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* The following table defines the expected "StructureSize" of SMB2 responses
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* in order by SMB2 command. This is similar to "wct" in SMB/CIFS responses.
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*
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* Note that commands are defined in smb2pdu.h in le16 but the array below is
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* indexed by command in host byte order
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*/
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static const __le16 smb2_rsp_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
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/* SMB2_NEGOTIATE */ __constant_cpu_to_le16(65),
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/* SMB2_SESSION_SETUP */ __constant_cpu_to_le16(9),
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/* SMB2_LOGOFF */ __constant_cpu_to_le16(4),
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/* SMB2_TREE_CONNECT */ __constant_cpu_to_le16(16),
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/* SMB2_TREE_DISCONNECT */ __constant_cpu_to_le16(4),
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/* SMB2_CREATE */ __constant_cpu_to_le16(89),
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/* SMB2_CLOSE */ __constant_cpu_to_le16(60),
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/* SMB2_FLUSH */ __constant_cpu_to_le16(4),
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/* SMB2_READ */ __constant_cpu_to_le16(17),
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/* SMB2_WRITE */ __constant_cpu_to_le16(17),
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/* SMB2_LOCK */ __constant_cpu_to_le16(4),
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/* SMB2_IOCTL */ __constant_cpu_to_le16(49),
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/* BB CHECK this ... not listed in documentation */
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/* SMB2_CANCEL */ __constant_cpu_to_le16(0),
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/* SMB2_ECHO */ __constant_cpu_to_le16(4),
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/* SMB2_QUERY_DIRECTORY */ __constant_cpu_to_le16(9),
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/* SMB2_CHANGE_NOTIFY */ __constant_cpu_to_le16(9),
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/* SMB2_QUERY_INFO */ __constant_cpu_to_le16(9),
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/* SMB2_SET_INFO */ __constant_cpu_to_le16(2),
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/* BB FIXME can also be 44 for lease break */
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/* SMB2_OPLOCK_BREAK */ __constant_cpu_to_le16(24)
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};
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int
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smb2_check_message(char *buf, unsigned int length)
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{
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struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
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struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
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__u64 mid = hdr->MessageId;
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__u32 len = get_rfc1002_length(buf);
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__u32 clc_len; /* calculated length */
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int command;
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/* BB disable following printk later */
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cFYI(1, "%s length: 0x%x, smb_buf_length: 0x%x", __func__, length, len);
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/*
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* Add function to do table lookup of StructureSize by command
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* ie Validate the wct via smb2_struct_sizes table above
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*/
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if (length < 2 + sizeof(struct smb2_hdr)) {
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if ((length >= sizeof(struct smb2_hdr)) && (hdr->Status != 0)) {
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pdu->StructureSize2 = 0;
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/*
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* As with SMB/CIFS, on some error cases servers may
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* not return wct properly
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*/
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return 0;
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} else {
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cERROR(1, "Length less than SMB header size");
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}
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return 1;
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}
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if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
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cERROR(1, "SMB length greater than maximum, mid=%lld", mid);
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return 1;
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}
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if (check_smb2_hdr(hdr, mid))
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return 1;
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if (hdr->StructureSize != SMB2_HEADER_SIZE) {
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cERROR(1, "Illegal structure size %d",
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le16_to_cpu(hdr->StructureSize));
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return 1;
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}
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command = le16_to_cpu(hdr->Command);
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if (command >= NUMBER_OF_SMB2_COMMANDS) {
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cERROR(1, "Illegal SMB2 command %d", command);
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return 1;
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}
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if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
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if (hdr->Status == 0 ||
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pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2) {
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/* error packets have 9 byte structure size */
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cERROR(1, "Illegal response size %u for command %d",
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le16_to_cpu(pdu->StructureSize2), command);
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return 1;
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}
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}
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if (4 + len != length) {
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cERROR(1, "Total length %u RFC1002 length %u mismatch mid %llu",
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length, 4 + len, mid);
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return 1;
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}
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clc_len = smb2_calc_size(hdr);
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if (4 + len != clc_len) {
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cFYI(1, "Calculated size %u length %u mismatch mid %llu",
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clc_len, 4 + len, mid);
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if (clc_len == 4 + len + 1) /* BB FIXME (fix samba) */
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return 0; /* BB workaround Samba 3 bug SessSetup rsp */
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return 1;
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}
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return 0;
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}
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/*
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* The size of the variable area depends on the offset and length fields
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* located in different fields for various SMB2 responses. SMB2 responses
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* with no variable length info, show an offset of zero for the offset field.
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*/
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static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
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/* SMB2_NEGOTIATE */ true,
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/* SMB2_SESSION_SETUP */ true,
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/* SMB2_LOGOFF */ false,
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/* SMB2_TREE_CONNECT */ false,
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/* SMB2_TREE_DISCONNECT */ false,
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/* SMB2_CREATE */ true,
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/* SMB2_CLOSE */ false,
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/* SMB2_FLUSH */ false,
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/* SMB2_READ */ true,
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/* SMB2_WRITE */ false,
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/* SMB2_LOCK */ false,
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/* SMB2_IOCTL */ true,
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/* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
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/* SMB2_ECHO */ false,
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/* SMB2_QUERY_DIRECTORY */ true,
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/* SMB2_CHANGE_NOTIFY */ true,
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/* SMB2_QUERY_INFO */ true,
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/* SMB2_SET_INFO */ false,
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/* SMB2_OPLOCK_BREAK */ false
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};
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/*
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* Returns the pointer to the beginning of the data area. Length of the data
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* area and the offset to it (from the beginning of the smb are also returned.
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*/
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char *
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smb2_get_data_area_len(int *off, int *len, struct smb2_hdr *hdr)
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{
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*off = 0;
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*len = 0;
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/* error responses do not have data area */
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if (hdr->Status && hdr->Status != STATUS_MORE_PROCESSING_REQUIRED &&
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(((struct smb2_err_rsp *)hdr)->StructureSize) ==
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SMB2_ERROR_STRUCTURE_SIZE2)
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return NULL;
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/*
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* Following commands have data areas so we have to get the location
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* of the data buffer offset and data buffer length for the particular
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* command.
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*/
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switch (hdr->Command) {
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case SMB2_NEGOTIATE:
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*off = le16_to_cpu(
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((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
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*len = le16_to_cpu(
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((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
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break;
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case SMB2_SESSION_SETUP:
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*off = le16_to_cpu(
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((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
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*len = le16_to_cpu(
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((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
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break;
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case SMB2_CREATE:
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*off = le32_to_cpu(
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((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
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*len = le32_to_cpu(
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((struct smb2_create_rsp *)hdr)->CreateContextsLength);
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break;
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case SMB2_QUERY_INFO:
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*off = le16_to_cpu(
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((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
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*len = le32_to_cpu(
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((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
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break;
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case SMB2_READ:
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case SMB2_QUERY_DIRECTORY:
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case SMB2_IOCTL:
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case SMB2_CHANGE_NOTIFY:
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default:
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/* BB FIXME for unimplemented cases above */
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cERROR(1, "no length check for command");
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break;
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}
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/*
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* Invalid length or offset probably means data area is invalid, but
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* we have little choice but to ignore the data area in this case.
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*/
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if (*off > 4096) {
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cERROR(1, "offset %d too large, data area ignored", *off);
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*len = 0;
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*off = 0;
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} else if (*off < 0) {
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cERROR(1, "negative offset %d to data invalid ignore data area",
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*off);
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*off = 0;
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*len = 0;
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} else if (*len < 0) {
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cERROR(1, "negative data length %d invalid, data area ignored",
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*len);
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*len = 0;
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} else if (*len > 128 * 1024) {
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cERROR(1, "data area larger than 128K: %d", *len);
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*len = 0;
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}
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/* return pointer to beginning of data area, ie offset from SMB start */
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if ((*off != 0) && (*len != 0))
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return hdr->ProtocolId + *off;
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else
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return NULL;
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}
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/*
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* Calculate the size of the SMB message based on the fixed header
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* portion, the number of word parameters and the data portion of the message.
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*/
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unsigned int
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smb2_calc_size(struct smb2_hdr *hdr)
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{
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struct smb2_pdu *pdu = (struct smb2_pdu *)hdr;
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int offset; /* the offset from the beginning of SMB to data area */
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int data_length; /* the length of the variable length data area */
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/* Structure Size has already been checked to make sure it is 64 */
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int len = 4 + le16_to_cpu(pdu->hdr.StructureSize);
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/*
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* StructureSize2, ie length of fixed parameter area has already
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* been checked to make sure it is the correct length.
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*/
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len += le16_to_cpu(pdu->StructureSize2);
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if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
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goto calc_size_exit;
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smb2_get_data_area_len(&offset, &data_length, hdr);
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cFYI(1, "SMB2 data length %d offset %d", data_length, offset);
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if (data_length > 0) {
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/*
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* Check to make sure that data area begins after fixed area,
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* Note that last byte of the fixed area is part of data area
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* for some commands, typically those with odd StructureSize,
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* so we must add one to the calculation (and 4 to account for
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* the size of the RFC1001 hdr.
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*/
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if (offset + 4 + 1 < len) {
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cERROR(1, "data area offset %d overlaps SMB2 header %d",
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offset + 4 + 1, len);
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data_length = 0;
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} else {
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len = 4 + offset + data_length;
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}
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}
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calc_size_exit:
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cFYI(1, "SMB2 len %d", len);
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return len;
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}
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/* Note: caller must free return buffer */
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__le16 *
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cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
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{
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int len;
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const char *start_of_path;
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__le16 *to;
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/* Windows doesn't allow paths beginning with \ */
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if (from[0] == '\\')
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start_of_path = from + 1;
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else
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start_of_path = from;
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to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
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cifs_sb->local_nls,
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cifs_sb->mnt_cifs_flags &
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CIFS_MOUNT_MAP_SPECIAL_CHR);
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return to;
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}
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