diff options
Diffstat (limited to 'fs/cifs/smb2misc.c')
| -rw-r--r-- | fs/cifs/smb2misc.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c new file mode 100644 index 00000000000..a4ff5d54755 --- /dev/null +++ b/fs/cifs/smb2misc.c @@ -0,0 +1,347 @@ +/* + * 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. + */ +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; +} |