fs/cifs/smb2misc.c - pub/scm/linux/kernel/git/elder/test - Git at Google

 /*
  *   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
 				cifs_dbg(VFS, "Received Request not response\n");
 		}
 	} else { /* bad signature or mid */
 		if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
 			cifs_dbg(VFS, "Bad protocol string signature header %x\n",
 				 *(unsigned int *) hdr->ProtocolId);
 		if (mid != hdr->MessageId)
 			cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
 				 mid, hdr->MessageId);
 	}
 	cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", 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 */
 	cifs_dbg(FYI, "%s length: 0x%x, smb_buf_length: 0x%x\n",
 		 __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 {
 			cifs_dbg(VFS, "Length less than SMB header size\n");
 		}
 		return 1;
 	}
 	if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
 		cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
 			 mid);
 		return 1;
 	}

 	if (check_smb2_hdr(hdr, mid))
 		return 1;

 	if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
 		cifs_dbg(VFS, "Illegal structure size %u\n",
 			 le16_to_cpu(hdr->StructureSize));
 		return 1;
 	}

 	command = le16_to_cpu(hdr->Command);
 	if (command >= NUMBER_OF_SMB2_COMMANDS) {
 		cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
 		return 1;
 	}

 	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
 		if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 ||
 		    pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
 			/* error packets have 9 byte structure size */
 			cifs_dbg(VFS, "Illegal response size %u for command %d\n",
 				 le16_to_cpu(pdu->StructureSize2), command);
 			return 1;
 		} else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
 			   && (le16_to_cpu(pdu->StructureSize2) != 44)
 			   && (le16_to_cpu(pdu->StructureSize2) != 36)) {
 			/* special case for SMB2.1 lease break message */
 			cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
 				 le16_to_cpu(pdu->StructureSize2));
 			return 1;
 		}
 	}

 	if (4 + len != length) {
 		cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
 			 length, 4 + len, mid);
 		return 1;
 	}

 	clc_len = smb2_calc_size(hdr);

 	if (4 + len != clc_len) {
 		cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
 			 clc_len, 4 + len, mid);
 		/* create failed on symlink */
 		if (command == SMB2_CREATE_HE &&
 		    hdr->Status == STATUS_STOPPED_ON_SYMLINK)
 			return 0;
 		/* Windows 7 server returns 24 bytes more */
 		if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
 			return 0;
 		/* server can return one byte more due to implied bcc[0] */
 		if (clc_len == 4 + len + 1)
 			return 0;

 		/*
 		 * MacOS server pads after SMB2.1 write response with 3 bytes
 		 * of junk. Other servers match RFC1001 len to actual
 		 * SMB2/SMB3 frame length (header + smb2 response specific data)
 		 * Log the server error (once), but allow it and continue
 		 * since the frame is parseable.
 		 */
 		if (clc_len < 4 /* RFC1001 header size */ + len) {
 			printk_once(KERN_WARNING
 				"SMB2 server sent bad RFC1001 len %d not %d\n",
 				len, clc_len - 4);
 			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:
 		*off = ((struct smb2_read_rsp *)hdr)->DataOffset;
 		*len = le32_to_cpu(((struct smb2_read_rsp *)hdr)->DataLength);
 		break;
 	case SMB2_QUERY_DIRECTORY:
 		*off = le16_to_cpu(
 		  ((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
 		*len = le32_to_cpu(
 		  ((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 */
 		cifs_dbg(VFS, "no length check for command\n");
 		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) {
 		cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
 		*len = 0;
 		*off = 0;
 	} else if (*off < 0) {
 		cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
 			 *off);
 		*off = 0;
 		*len = 0;
 	} else if (*len < 0) {
 		cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
 			 *len);
 		*len = 0;
 	} else if (*len > 128 * 1024) {
 		cifs_dbg(VFS, "data area larger than 128K: %d\n", *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(void *buf)
 {
 	struct smb2_hdr *hdr = (struct smb2_hdr *)buf;
 	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);
 	cifs_dbg(FYI, "SMB2 data length %d offset %d\n", 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) {
 			cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
 				 offset + 4 + 1, len);
 			data_length = 0;
 		} else {
 			len = 4 + offset + data_length;
 		}
 	}
 calc_size_exit:
 	cifs_dbg(FYI, "SMB2 len %d\n", 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;
 }

 __le32
 smb2_get_lease_state(struct cifsInodeInfo *cinode)
 {
 	__le32 lease = 0;

 	if (CIFS_CACHE_WRITE(cinode))
 		lease |= SMB2_LEASE_WRITE_CACHING;
 	if (CIFS_CACHE_HANDLE(cinode))
 		lease |= SMB2_LEASE_HANDLE_CACHING;
 	if (CIFS_CACHE_READ(cinode))
 		lease |= SMB2_LEASE_READ_CACHING;
 	return lease;
 }

 struct smb2_lease_break_work {
 	struct work_struct lease_break;
 	struct tcon_link *tlink;
 	__u8 lease_key[16];
 	__le32 lease_state;
 };

 static void
 cifs_ses_oplock_break(struct work_struct *work)
 {
 	struct smb2_lease_break_work *lw = container_of(work,
 				struct smb2_lease_break_work, lease_break);
 	int rc;

 	rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
 			      lw->lease_state);
 	cifs_dbg(FYI, "Lease release rc %d\n", rc);
 	cifs_put_tlink(lw->tlink);
 	kfree(lw);
 }

 static bool
 smb2_tcon_has_lease(struct cifs_tcon *tcon, struct smb2_lease_break *rsp,
 		    struct smb2_lease_break_work *lw)
 {
 	bool found;
 	__u8 lease_state;
 	struct list_head *tmp;
 	struct cifsFileInfo *cfile;
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_pending_open *open;
 	struct cifsInodeInfo *cinode;
 	int ack_req = le32_to_cpu(rsp->Flags &
 				  SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);

 	lease_state = le32_to_cpu(rsp->NewLeaseState);

 	list_for_each(tmp, &tcon->openFileList) {
 		cfile = list_entry(tmp, struct cifsFileInfo, tlist);
 		cinode = CIFS_I(cfile->dentry->d_inode);

 		if (memcmp(cinode->lease_key, rsp->LeaseKey,
 							SMB2_LEASE_KEY_SIZE))
 			continue;

 		cifs_dbg(FYI, "found in the open list\n");
 		cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 			 le32_to_cpu(rsp->NewLeaseState));

 		server->ops->set_oplock_level(cinode, lease_state, 0, NULL);

 		if (ack_req)
 			cfile->oplock_break_cancelled = false;
 		else
 			cfile->oplock_break_cancelled = true;

 		queue_work(cifsiod_wq, &cfile->oplock_break);
 		kfree(lw);
 		return true;
 	}

 	found = false;
 	list_for_each_entry(open, &tcon->pending_opens, olist) {
 		if (memcmp(open->lease_key, rsp->LeaseKey,
 			   SMB2_LEASE_KEY_SIZE))
 			continue;

 		if (!found && ack_req) {
 			found = true;
 			memcpy(lw->lease_key, open->lease_key,
 			       SMB2_LEASE_KEY_SIZE);
 			lw->tlink = cifs_get_tlink(open->tlink);
 			queue_work(cifsiod_wq, &lw->lease_break);
 		}

 		cifs_dbg(FYI, "found in the pending open list\n");
 		cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
 			 le32_to_cpu(rsp->NewLeaseState));

 		open->oplock = lease_state;
 	}
 	return found;
 }

 static bool
 smb2_is_valid_lease_break(char *buffer)
 {
 	struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
 	struct list_head *tmp, *tmp1, *tmp2;
 	struct TCP_Server_Info *server;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct smb2_lease_break_work *lw;

 	lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
 	if (!lw)
 		return false;

 	INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
 	lw->lease_state = rsp->NewLeaseState;

 	cifs_dbg(FYI, "Checking for lease break\n");

 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each(tmp, &cifs_tcp_ses_list) {
 		server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);

 		list_for_each(tmp1, &server->smb_ses_list) {
 			ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);

 			spin_lock(&cifs_file_list_lock);
 			list_for_each(tmp2, &ses->tcon_list) {
 				tcon = list_entry(tmp2, struct cifs_tcon,
 						  tcon_list);
 				cifs_stats_inc(
 				    &tcon->stats.cifs_stats.num_oplock_brks);
 				if (smb2_tcon_has_lease(tcon, rsp, lw)) {
 					spin_unlock(&cifs_file_list_lock);
 					spin_unlock(&cifs_tcp_ses_lock);
 					return true;
 				}
 			}
 			spin_unlock(&cifs_file_list_lock);
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
 	kfree(lw);
 	cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
 	return false;
 }

 bool
 smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
 {
 	struct smb2_oplock_break *rsp = (struct smb2_oplock_break *)buffer;
 	struct list_head *tmp, *tmp1, *tmp2;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *cinode;
 	struct cifsFileInfo *cfile;

 	cifs_dbg(FYI, "Checking for oplock break\n");

 	if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
 		return false;

 	if (rsp->StructureSize !=
 				smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
 		if (le16_to_cpu(rsp->StructureSize) == 44)
 			return smb2_is_valid_lease_break(buffer);
 		else
 			return false;
 	}

 	cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);

 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each(tmp, &server->smb_ses_list) {
 		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 		list_for_each(tmp1, &ses->tcon_list) {
 			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);

 			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 			spin_lock(&cifs_file_list_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				cfile = list_entry(tmp2, struct cifsFileInfo,
 						     tlist);
 				if (rsp->PersistentFid !=
 				    cfile->fid.persistent_fid ||
 				    rsp->VolatileFid !=
 				    cfile->fid.volatile_fid)
 					continue;

 				cifs_dbg(FYI, "file id match, oplock break\n");
 				cinode = CIFS_I(cfile->dentry->d_inode);

 				if (!CIFS_CACHE_WRITE(cinode) &&
 				    rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 					cfile->oplock_break_cancelled = true;
 				else
 					cfile->oplock_break_cancelled = false;

 				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
 					&cinode->flags);

 				/*
 				 * Set flag if the server downgrades the oplock
 				 * to L2 else clear.
 				 */
 				if (rsp->OplockLevel)
 					set_bit(
 					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 					   &cinode->flags);
 				else
 					clear_bit(
 					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 					   &cinode->flags);

 				queue_work(cifsiod_wq, &cfile->oplock_break);

 				spin_unlock(&cifs_file_list_lock);
 				spin_unlock(&cifs_tcp_ses_lock);
 				return true;
 			}
 			spin_unlock(&cifs_file_list_lock);
 			spin_unlock(&cifs_tcp_ses_lock);
 			cifs_dbg(FYI, "No matching file for oplock break\n");
 			return true;
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
 	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
 	return false;
 }
	/*
	* 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
	cifs_dbg(VFS, "Received Request not response\n");
	}
	} else { /* bad signature or mid */
	if ((__le32 )hdr->ProtocolId != SMB2_PROTO_NUMBER)
	cifs_dbg(VFS, "Bad protocol string signature header %x\n",
	(unsigned int ) hdr->ProtocolId);
	if (mid != hdr->MessageId)
	cifs_dbg(VFS, "Mids do not match: %llu and %llu\n",
	mid, hdr->MessageId);
	}
	cifs_dbg(VFS, "Bad SMB detected. The Mid=%llu\n", 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 */
	cifs_dbg(FYI, "%s length: 0x%x, smb_buf_length: 0x%x\n",
	__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 {
	cifs_dbg(VFS, "Length less than SMB header size\n");
	}
	return 1;
	}
	if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
	cifs_dbg(VFS, "SMB length greater than maximum, mid=%llu\n",
	mid);
	return 1;
	}

	if (check_smb2_hdr(hdr, mid))
	return 1;

	if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
	cifs_dbg(VFS, "Illegal structure size %u\n",
	le16_to_cpu(hdr->StructureSize));
	return 1;
	}

	command = le16_to_cpu(hdr->Command);
	if (command >= NUMBER_OF_SMB2_COMMANDS) {
	cifs_dbg(VFS, "Illegal SMB2 command %d\n", command);
	return 1;
	}

	if (smb2_rsp_struct_sizes[command] != pdu->StructureSize2) {
	if (command != SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0 \|\|
	pdu->StructureSize2 != SMB2_ERROR_STRUCTURE_SIZE2)) {
	/* error packets have 9 byte structure size */
	cifs_dbg(VFS, "Illegal response size %u for command %d\n",
	le16_to_cpu(pdu->StructureSize2), command);
	return 1;
	} else if (command == SMB2_OPLOCK_BREAK_HE && (hdr->Status == 0)
	&& (le16_to_cpu(pdu->StructureSize2) != 44)
	&& (le16_to_cpu(pdu->StructureSize2) != 36)) {
	/* special case for SMB2.1 lease break message */
	cifs_dbg(VFS, "Illegal response size %d for oplock break\n",
	le16_to_cpu(pdu->StructureSize2));
	return 1;
	}
	}

	if (4 + len != length) {
	cifs_dbg(VFS, "Total length %u RFC1002 length %u mismatch mid %llu\n",
	length, 4 + len, mid);
	return 1;
	}

	clc_len = smb2_calc_size(hdr);

	if (4 + len != clc_len) {
	cifs_dbg(FYI, "Calculated size %u length %u mismatch mid %llu\n",
	clc_len, 4 + len, mid);
	/* create failed on symlink */
	if (command == SMB2_CREATE_HE &&
	hdr->Status == STATUS_STOPPED_ON_SYMLINK)
	return 0;
	/* Windows 7 server returns 24 bytes more */
	if (clc_len + 20 == len && command == SMB2_OPLOCK_BREAK_HE)
	return 0;
	/* server can return one byte more due to implied bcc[0] */
	if (clc_len == 4 + len + 1)
	return 0;

	/*
	* MacOS server pads after SMB2.1 write response with 3 bytes
	* of junk. Other servers match RFC1001 len to actual
	* SMB2/SMB3 frame length (header + smb2 response specific data)
	* Log the server error (once), but allow it and continue
	* since the frame is parseable.
	*/
	if (clc_len < 4 /* RFC1001 header size */ + len) {
	printk_once(KERN_WARNING
	"SMB2 server sent bad RFC1001 len %d not %d\n",
	len, clc_len - 4);
	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:
	off = ((struct smb2_read_rsp )hdr)->DataOffset;
	len = le32_to_cpu(((struct smb2_read_rsp )hdr)->DataLength);
	break;
	case SMB2_QUERY_DIRECTORY:
	*off = le16_to_cpu(
	((struct smb2_query_directory_rsp *)hdr)->OutputBufferOffset);
	*len = le32_to_cpu(
	((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 */
	cifs_dbg(VFS, "no length check for command\n");
	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) {
	cifs_dbg(VFS, "offset %d too large, data area ignored\n", *off);
	*len = 0;
	*off = 0;
	} else if (*off < 0) {
	cifs_dbg(VFS, "negative offset %d to data invalid ignore data area\n",
	*off);
	*off = 0;
	*len = 0;
	} else if (*len < 0) {
	cifs_dbg(VFS, "negative data length %d invalid, data area ignored\n",
	*len);
	*len = 0;
	} else if (len > 128 1024) {
	cifs_dbg(VFS, "data area larger than 128K: %d\n", *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(void *buf)
	{
	struct smb2_hdr hdr = (struct smb2_hdr )buf;
	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);
	cifs_dbg(FYI, "SMB2 data length %d offset %d\n", 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) {
	cifs_dbg(VFS, "data area offset %d overlaps SMB2 header %d\n",
	offset + 4 + 1, len);
	data_length = 0;
	} else {
	len = 4 + offset + data_length;
	}
	}
	calc_size_exit:
	cifs_dbg(FYI, "SMB2 len %d\n", 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;
	}

	__le32
	smb2_get_lease_state(struct cifsInodeInfo *cinode)
	{
	__le32 lease = 0;

	if (CIFS_CACHE_WRITE(cinode))
	lease \|= SMB2_LEASE_WRITE_CACHING;
	if (CIFS_CACHE_HANDLE(cinode))
	lease \|= SMB2_LEASE_HANDLE_CACHING;
	if (CIFS_CACHE_READ(cinode))
	lease \|= SMB2_LEASE_READ_CACHING;
	return lease;
	}

	struct smb2_lease_break_work {
	struct work_struct lease_break;
	struct tcon_link *tlink;
	__u8 lease_key[16];
	__le32 lease_state;
	};

	static void
	cifs_ses_oplock_break(struct work_struct *work)
	{
	struct smb2_lease_break_work *lw = container_of(work,
	struct smb2_lease_break_work, lease_break);
	int rc;

	rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
	lw->lease_state);
	cifs_dbg(FYI, "Lease release rc %d\n", rc);
	cifs_put_tlink(lw->tlink);
	kfree(lw);
	}

	static bool
	smb2_tcon_has_lease(struct cifs_tcon tcon, struct smb2_lease_break rsp,
	struct smb2_lease_break_work *lw)
	{
	bool found;
	__u8 lease_state;
	struct list_head *tmp;
	struct cifsFileInfo *cfile;
	struct TCP_Server_Info *server = tcon->ses->server;
	struct cifs_pending_open *open;
	struct cifsInodeInfo *cinode;
	int ack_req = le32_to_cpu(rsp->Flags &
	SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);

	lease_state = le32_to_cpu(rsp->NewLeaseState);

	list_for_each(tmp, &tcon->openFileList) {
	cfile = list_entry(tmp, struct cifsFileInfo, tlist);
	cinode = CIFS_I(cfile->dentry->d_inode);

	if (memcmp(cinode->lease_key, rsp->LeaseKey,
	SMB2_LEASE_KEY_SIZE))
	continue;

	cifs_dbg(FYI, "found in the open list\n");
	cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
	le32_to_cpu(rsp->NewLeaseState));

	server->ops->set_oplock_level(cinode, lease_state, 0, NULL);

	if (ack_req)
	cfile->oplock_break_cancelled = false;
	else
	cfile->oplock_break_cancelled = true;

	queue_work(cifsiod_wq, &cfile->oplock_break);
	kfree(lw);
	return true;
	}

	found = false;
	list_for_each_entry(open, &tcon->pending_opens, olist) {
	if (memcmp(open->lease_key, rsp->LeaseKey,
	SMB2_LEASE_KEY_SIZE))
	continue;

	if (!found && ack_req) {
	found = true;
	memcpy(lw->lease_key, open->lease_key,
	SMB2_LEASE_KEY_SIZE);
	lw->tlink = cifs_get_tlink(open->tlink);
	queue_work(cifsiod_wq, &lw->lease_break);
	}

	cifs_dbg(FYI, "found in the pending open list\n");
	cifs_dbg(FYI, "lease key match, lease break 0x%x\n",
	le32_to_cpu(rsp->NewLeaseState));

	open->oplock = lease_state;
	}
	return found;
	}

	static bool
	smb2_is_valid_lease_break(char *buffer)
	{
	struct smb2_lease_break rsp = (struct smb2_lease_break )buffer;
	struct list_head tmp, tmp1, *tmp2;
	struct TCP_Server_Info *server;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct smb2_lease_break_work *lw;

	lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
	if (!lw)
	return false;

	INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
	lw->lease_state = rsp->NewLeaseState;

	cifs_dbg(FYI, "Checking for lease break\n");

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &cifs_tcp_ses_list) {
	server = list_entry(tmp, struct TCP_Server_Info, tcp_ses_list);

	list_for_each(tmp1, &server->smb_ses_list) {
	ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);

	spin_lock(&cifs_file_list_lock);
	list_for_each(tmp2, &ses->tcon_list) {
	tcon = list_entry(tmp2, struct cifs_tcon,
	tcon_list);
	cifs_stats_inc(
	&tcon->stats.cifs_stats.num_oplock_brks);
	if (smb2_tcon_has_lease(tcon, rsp, lw)) {
	spin_unlock(&cifs_file_list_lock);
	spin_unlock(&cifs_tcp_ses_lock);
	return true;
	}
	}
	spin_unlock(&cifs_file_list_lock);
	}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	kfree(lw);
	cifs_dbg(FYI, "Can not process lease break - no lease matched\n");
	return false;
	}

	bool
	smb2_is_valid_oplock_break(char buffer, struct TCP_Server_Info server)
	{
	struct smb2_oplock_break rsp = (struct smb2_oplock_break )buffer;
	struct list_head tmp, tmp1, *tmp2;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct cifsInodeInfo *cinode;
	struct cifsFileInfo *cfile;

	cifs_dbg(FYI, "Checking for oplock break\n");

	if (rsp->hdr.Command != SMB2_OPLOCK_BREAK)
	return false;

	if (rsp->StructureSize !=
	smb2_rsp_struct_sizes[SMB2_OPLOCK_BREAK_HE]) {
	if (le16_to_cpu(rsp->StructureSize) == 44)
	return smb2_is_valid_lease_break(buffer);
	else
	return false;
	}

	cifs_dbg(FYI, "oplock level 0x%x\n", rsp->OplockLevel);

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &server->smb_ses_list) {
	ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
	list_for_each(tmp1, &ses->tcon_list) {
	tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);

	cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
	spin_lock(&cifs_file_list_lock);
	list_for_each(tmp2, &tcon->openFileList) {
	cfile = list_entry(tmp2, struct cifsFileInfo,
	tlist);
	if (rsp->PersistentFid !=
	cfile->fid.persistent_fid \|\|
	rsp->VolatileFid !=
	cfile->fid.volatile_fid)
	continue;

	cifs_dbg(FYI, "file id match, oplock break\n");
	cinode = CIFS_I(cfile->dentry->d_inode);

	if (!CIFS_CACHE_WRITE(cinode) &&
	rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
	cfile->oplock_break_cancelled = true;
	else
	cfile->oplock_break_cancelled = false;

	set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
	&cinode->flags);

	/*
	* Set flag if the server downgrades the oplock
	* to L2 else clear.
	*/
	if (rsp->OplockLevel)
	set_bit(
	CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
	&cinode->flags);
	else
	clear_bit(
	CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
	&cinode->flags);

	queue_work(cifsiod_wq, &cfile->oplock_break);

	spin_unlock(&cifs_file_list_lock);
	spin_unlock(&cifs_tcp_ses_lock);
	return true;
	}
	spin_unlock(&cifs_file_list_lock);
	spin_unlock(&cifs_tcp_ses_lock);
	cifs_dbg(FYI, "No matching file for oplock break\n");
	return true;
	}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
	return false;
	}