/*
* 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: %llu and %llu", mid,
hdr->MessageId);
}
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 < sizeof(struct smb2_pdu)) {
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=%llu", mid);
return 1;
}
if (check_smb2_hdr(hdr, mid))
return 1;
if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
cERROR(1, "Illegal structure size %u",
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);
/* server can return one byte more */
if (clc_len == 4 + len + 1)
return 0;
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.
*/
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:
*off = le16_to_cpu(
((struct smb2_negotiate_rsp *)hdr)->SecurityBufferOffset);
*len = le16_to_cpu(
((struct smb2_negotiate_rsp *)hdr)->SecurityBufferLength);
break;
case SMB2_SESSION_SETUP:
*off = le16_to_cpu(
((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferOffset);
*len = le16_to_cpu(
((struct smb2_sess_setup_rsp *)hdr)->SecurityBufferLength);
break;
case SMB2_CREATE:
*off = le32_to_cpu(
((struct smb2_create_rsp *)hdr)->CreateContextsOffset);
*len = le32_to_cpu(
((struct smb2_create_rsp *)hdr)->CreateContextsLength);
break;
case SMB2_QUERY_INFO:
*off = le16_to_cpu(
((struct smb2_query_info_rsp *)hdr)->OutputBufferOffset);
*len = le32_to_cpu(
((struct smb2_query_info_rsp *)hdr)->OutputBufferLength);
break;
case SMB2_READ:
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;
}
/* Note: caller must free return buffer */
__le16 *
cifs_convert_path_to_utf16(const char *from, struct cifs_sb_info *cifs_sb)
{
int len;
const char *start_of_path;
__le16 *to;
/* Windows doesn't allow paths beginning with \ */
if (from[0] == '\\')
start_of_path = from + 1;
else
start_of_path = from;
to = cifs_strndup_to_utf16(start_of_path, PATH_MAX, &len,
cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
return to;
}
