fs/cifs/misc.c - kernel/msm-4.9 - Gitiles

 /*
  *   fs/cifs/misc.c
  *
  *   Copyright (C) International Business Machines  Corp., 2002,2008
  *   Author(s): Steve French (sfrench@us.ibm.com)
  *
  *   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/slab.h>
 #include <linux/ctype.h>
 #include <linux/mempool.h>
 #include "cifspdu.h"
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "smberr.h"
 #include "nterr.h"
 #include "cifs_unicode.h"

 extern mempool_t *cifs_sm_req_poolp;
 extern mempool_t *cifs_req_poolp;

 /* The xid serves as a useful identifier for each incoming vfs request,
    in a similar way to the mid which is useful to track each sent smb,
    and CurrentXid can also provide a running counter (although it
    will eventually wrap past zero) of the total vfs operations handled
    since the cifs fs was mounted */

 unsigned int
 _GetXid(void)
 {
 	unsigned int xid;

 	spin_lock(&GlobalMid_Lock);
 	GlobalTotalActiveXid++;

 	/* keep high water mark for number of simultaneous ops in filesystem */
 	if (GlobalTotalActiveXid > GlobalMaxActiveXid)
 		GlobalMaxActiveXid = GlobalTotalActiveXid;
 	if (GlobalTotalActiveXid > 65000)
 		cFYI(1, "warning: more than 65000 requests active");
 	xid = GlobalCurrentXid++;
 	spin_unlock(&GlobalMid_Lock);
 	return xid;
 }

 void
 _FreeXid(unsigned int xid)
 {
 	spin_lock(&GlobalMid_Lock);
 	/* if (GlobalTotalActiveXid == 0)
 		BUG(); */
 	GlobalTotalActiveXid--;
 	spin_unlock(&GlobalMid_Lock);
 }

 struct cifs_ses *
 sesInfoAlloc(void)
 {
 	struct cifs_ses *ret_buf;

 	ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
 	if (ret_buf) {
 		atomic_inc(&sesInfoAllocCount);
 		ret_buf->status = CifsNew;
 		++ret_buf->ses_count;
 		INIT_LIST_HEAD(&ret_buf->smb_ses_list);
 		INIT_LIST_HEAD(&ret_buf->tcon_list);
 		mutex_init(&ret_buf->session_mutex);
 	}
 	return ret_buf;
 }

 void
 sesInfoFree(struct cifs_ses *buf_to_free)
 {
 	if (buf_to_free == NULL) {
 		cFYI(1, "Null buffer passed to sesInfoFree");
 		return;
 	}

 	atomic_dec(&sesInfoAllocCount);
 	kfree(buf_to_free->serverOS);
 	kfree(buf_to_free->serverDomain);
 	kfree(buf_to_free->serverNOS);
 	if (buf_to_free->password) {
 		memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 		kfree(buf_to_free->password);
 	}
 	kfree(buf_to_free->user_name);
 	kfree(buf_to_free->domainName);
 	kfree(buf_to_free);
 }

 struct cifs_tcon *
 tconInfoAlloc(void)
 {
 	struct cifs_tcon *ret_buf;
 	ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 	if (ret_buf) {
 		atomic_inc(&tconInfoAllocCount);
 		ret_buf->tidStatus = CifsNew;
 		++ret_buf->tc_count;
 		INIT_LIST_HEAD(&ret_buf->openFileList);
 		INIT_LIST_HEAD(&ret_buf->tcon_list);
 #ifdef CONFIG_CIFS_STATS
 		spin_lock_init(&ret_buf->stat_lock);
 #endif
 	}
 	return ret_buf;
 }

 void
 tconInfoFree(struct cifs_tcon *buf_to_free)
 {
 	if (buf_to_free == NULL) {
 		cFYI(1, "Null buffer passed to tconInfoFree");
 		return;
 	}
 	atomic_dec(&tconInfoAllocCount);
 	kfree(buf_to_free->nativeFileSystem);
 	if (buf_to_free->password) {
 		memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 		kfree(buf_to_free->password);
 	}
 	kfree(buf_to_free);
 }

 struct smb_hdr *
 cifs_buf_get(void)
 {
 	struct smb_hdr *ret_buf = NULL;

 /* We could use negotiated size instead of max_msgsize -
    but it may be more efficient to always alloc same size
    albeit slightly larger than necessary and maxbuffersize
    defaults to this and can not be bigger */
 	ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);

 	/* clear the first few header bytes */
 	/* for most paths, more is cleared in header_assemble */
 	if (ret_buf) {
 		memset(ret_buf, 0, sizeof(struct smb_hdr) + 3);
 		atomic_inc(&bufAllocCount);
 #ifdef CONFIG_CIFS_STATS2
 		atomic_inc(&totBufAllocCount);
 #endif /* CONFIG_CIFS_STATS2 */
 	}

 	return ret_buf;
 }

 void
 cifs_buf_release(void *buf_to_free)
 {
 	if (buf_to_free == NULL) {
 		/* cFYI(1, "Null buffer passed to cifs_buf_release");*/
 		return;
 	}
 	mempool_free(buf_to_free, cifs_req_poolp);

 	atomic_dec(&bufAllocCount);
 	return;
 }

 struct smb_hdr *
 cifs_small_buf_get(void)
 {
 	struct smb_hdr *ret_buf = NULL;

 /* We could use negotiated size instead of max_msgsize -
    but it may be more efficient to always alloc same size
    albeit slightly larger than necessary and maxbuffersize
    defaults to this and can not be bigger */
 	ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 	if (ret_buf) {
 	/* No need to clear memory here, cleared in header assemble */
 	/*	memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 		atomic_inc(&smBufAllocCount);
 #ifdef CONFIG_CIFS_STATS2
 		atomic_inc(&totSmBufAllocCount);
 #endif /* CONFIG_CIFS_STATS2 */

 	}
 	return ret_buf;
 }

 void
 cifs_small_buf_release(void *buf_to_free)
 {

 	if (buf_to_free == NULL) {
 		cFYI(1, "Null buffer passed to cifs_small_buf_release");
 		return;
 	}
 	mempool_free(buf_to_free, cifs_sm_req_poolp);

 	atomic_dec(&smBufAllocCount);
 	return;
 }

 /*
  * Find a free multiplex id (SMB mid). Otherwise there could be
  * mid collisions which might cause problems, demultiplexing the
  * wrong response to this request. Multiplex ids could collide if
  * one of a series requests takes much longer than the others, or
  * if a very large number of long lived requests (byte range
  * locks or FindNotify requests) are pending. No more than
  * 64K-1 requests can be outstanding at one time. If no
  * mids are available, return zero. A future optimization
  * could make the combination of mids and uid the key we use
  * to demultiplex on (rather than mid alone).
  * In addition to the above check, the cifs demultiplex
  * code already used the command code as a secondary
  * check of the frame and if signing is negotiated the
  * response would be discarded if the mid were the same
  * but the signature was wrong. Since the mid is not put in the
  * pending queue until later (when it is about to be dispatched)
  * we do have to limit the number of outstanding requests
  * to somewhat less than 64K-1 although it is hard to imagine
  * so many threads being in the vfs at one time.
  */
 __u64 GetNextMid(struct TCP_Server_Info *server)
 {
 	__u64 mid = 0;
 	__u16 last_mid, cur_mid;
 	bool collision;

 	spin_lock(&GlobalMid_Lock);

 	/* mid is 16 bit only for CIFS/SMB */
 	cur_mid = (__u16)((server->CurrentMid) & 0xffff);
 	/* we do not want to loop forever */
 	last_mid = cur_mid;
 	cur_mid++;

 	/*
 	 * This nested loop looks more expensive than it is.
 	 * In practice the list of pending requests is short,
 	 * fewer than 50, and the mids are likely to be unique
 	 * on the first pass through the loop unless some request
 	 * takes longer than the 64 thousand requests before it
 	 * (and it would also have to have been a request that
 	 * did not time out).
 	 */
 	while (cur_mid != last_mid) {
 		struct mid_q_entry *mid_entry;
 		unsigned int num_mids;

 		collision = false;
 		if (cur_mid == 0)
 			cur_mid++;

 		num_mids = 0;
 		list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) {
 			++num_mids;
 			if (mid_entry->mid == cur_mid &&
 			    mid_entry->mid_state == MID_REQUEST_SUBMITTED) {
 				/* This mid is in use, try a different one */
 				collision = true;
 				break;
 			}
 		}

 		/*
 		 * if we have more than 32k mids in the list, then something
 		 * is very wrong. Possibly a local user is trying to DoS the
 		 * box by issuing long-running calls and SIGKILL'ing them. If
 		 * we get to 2^16 mids then we're in big trouble as this
 		 * function could loop forever.
 		 *
 		 * Go ahead and assign out the mid in this situation, but force
 		 * an eventual reconnect to clean out the pending_mid_q.
 		 */
 		if (num_mids > 32768)
 			server->tcpStatus = CifsNeedReconnect;

 		if (!collision) {
 			mid = (__u64)cur_mid;
 			server->CurrentMid = mid;
 			break;
 		}
 		cur_mid++;
 	}
 	spin_unlock(&GlobalMid_Lock);
 	return mid;
 }

 /* NB: MID can not be set if treeCon not passed in, in that
    case it is responsbility of caller to set the mid */
 void
 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 		const struct cifs_tcon *treeCon, int word_count
 		/* length of fixed section (word count) in two byte units  */)
 {
 	char *temp = (char *) buffer;

 	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */

 	buffer->smb_buf_length = cpu_to_be32(
 	    (2 * word_count) + sizeof(struct smb_hdr) -
 	    4 /*  RFC 1001 length field does not count */  +
 	    2 /* for bcc field itself */) ;

 	buffer->Protocol[0] = 0xFF;
 	buffer->Protocol[1] = 'S';
 	buffer->Protocol[2] = 'M';
 	buffer->Protocol[3] = 'B';
 	buffer->Command = smb_command;
 	buffer->Flags = 0x00;	/* case sensitive */
 	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 	buffer->Pid = cpu_to_le16((__u16)current->tgid);
 	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 	if (treeCon) {
 		buffer->Tid = treeCon->tid;
 		if (treeCon->ses) {
 			if (treeCon->ses->capabilities & CAP_UNICODE)
 				buffer->Flags2 |= SMBFLG2_UNICODE;
 			if (treeCon->ses->capabilities & CAP_STATUS32)
 				buffer->Flags2 |= SMBFLG2_ERR_STATUS;

 			/* Uid is not converted */
 			buffer->Uid = treeCon->ses->Suid;
 			buffer->Mid = GetNextMid(treeCon->ses->server);
 		}
 		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 			buffer->Flags2 |= SMBFLG2_DFS;
 		if (treeCon->nocase)
 			buffer->Flags  |= SMBFLG_CASELESS;
 		if ((treeCon->ses) && (treeCon->ses->server))
 			if (treeCon->ses->server->sec_mode &
 			  (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 				buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 	}

 /*  endian conversion of flags is now done just before sending */
 	buffer->WordCount = (char) word_count;
 	return;
 }

 static int
 check_smb_hdr(struct smb_hdr *smb, __u16 mid)
 {
 	/* does it have the right SMB "signature" ? */
 	if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 		cERROR(1, "Bad protocol string signature header 0x%x",
 			*(unsigned int *)smb->Protocol);
 		return 1;
 	}

 	/* Make sure that message ids match */
 	if (mid != smb->Mid) {
 		cERROR(1, "Mids do not match. received=%u expected=%u",
 			smb->Mid, mid);
 		return 1;
 	}

 	/* if it's a response then accept */
 	if (smb->Flags & SMBFLG_RESPONSE)
 		return 0;

 	/* only one valid case where server sends us request */
 	if (smb->Command == SMB_COM_LOCKING_ANDX)
 		return 0;

 	cERROR(1, "Server sent request, not response. mid=%u", smb->Mid);
 	return 1;
 }

 int
 checkSMB(char *buf, unsigned int total_read)
 {
 	struct smb_hdr *smb = (struct smb_hdr *)buf;
 	__u16 mid = smb->Mid;
 	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 	__u32 clc_len;  /* calculated length */
 	cFYI(0, "checkSMB Length: 0x%x, smb_buf_length: 0x%x",
 		total_read, rfclen);

 	/* is this frame too small to even get to a BCC? */
 	if (total_read < 2 + sizeof(struct smb_hdr)) {
 		if ((total_read >= sizeof(struct smb_hdr) - 1)
 			    && (smb->Status.CifsError != 0)) {
 			/* it's an error return */
 			smb->WordCount = 0;
 			/* some error cases do not return wct and bcc */
 			return 0;
 		} else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 				(smb->WordCount == 0)) {
 			char *tmp = (char *)smb;
 			/* Need to work around a bug in two servers here */
 			/* First, check if the part of bcc they sent was zero */
 			if (tmp[sizeof(struct smb_hdr)] == 0) {
 				/* some servers return only half of bcc
 				 * on simple responses (wct, bcc both zero)
 				 * in particular have seen this on
 				 * ulogoffX and FindClose. This leaves
 				 * one byte of bcc potentially unitialized
 				 */
 				/* zero rest of bcc */
 				tmp[sizeof(struct smb_hdr)+1] = 0;
 				return 0;
 			}
 			cERROR(1, "rcvd invalid byte count (bcc)");
 		} else {
 			cERROR(1, "Length less than smb header size");
 		}
 		return -EIO;
 	}

 	/* otherwise, there is enough to get to the BCC */
 	if (check_smb_hdr(smb, mid))
 		return -EIO;
 	clc_len = smbCalcSize(smb);

 	if (4 + rfclen != total_read) {
 		cERROR(1, "Length read does not match RFC1001 length %d",
 				rfclen);
 		return -EIO;
 	}

 	if (4 + rfclen != clc_len) {
 		/* check if bcc wrapped around for large read responses */
 		if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 			/* check if lengths match mod 64K */
 			if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 				return 0; /* bcc wrapped */
 		}
 		cFYI(1, "Calculated size %u vs length %u mismatch for mid=%u",
 				clc_len, 4 + rfclen, smb->Mid);

 		if (4 + rfclen < clc_len) {
 			cERROR(1, "RFC1001 size %u smaller than SMB for mid=%u",
 					rfclen, smb->Mid);
 			return -EIO;
 		} else if (rfclen > clc_len + 512) {
 			/*
 			 * Some servers (Windows XP in particular) send more
 			 * data than the lengths in the SMB packet would
 			 * indicate on certain calls (byte range locks and
 			 * trans2 find first calls in particular). While the
 			 * client can handle such a frame by ignoring the
 			 * trailing data, we choose limit the amount of extra
 			 * data to 512 bytes.
 			 */
 			cERROR(1, "RFC1001 size %u more than 512 bytes larger "
 				  "than SMB for mid=%u", rfclen, smb->Mid);
 			return -EIO;
 		}
 	}
 	return 0;
 }

 bool
 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 {
 	struct smb_hdr *buf = (struct smb_hdr *)buffer;
 	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 	struct list_head *tmp, *tmp1, *tmp2;
 	struct cifs_ses *ses;
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *pCifsInode;
 	struct cifsFileInfo *netfile;

 	cFYI(1, "Checking for oplock break or dnotify response");
 	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 	   (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 		struct smb_com_transaction_change_notify_rsp *pSMBr =
 			(struct smb_com_transaction_change_notify_rsp *)buf;
 		struct file_notify_information *pnotify;
 		__u32 data_offset = 0;
 		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 			data_offset = le32_to_cpu(pSMBr->DataOffset);

 			pnotify = (struct file_notify_information *)
 				((char *)&pSMBr->hdr.Protocol + data_offset);
 			cFYI(1, "dnotify on %s Action: 0x%x",
 				 pnotify->FileName, pnotify->Action);
 			/*   cifs_dump_mem("Rcvd notify Data: ",buf,
 				sizeof(struct smb_hdr)+60); */
 			return true;
 		}
 		if (pSMBr->hdr.Status.CifsError) {
 			cFYI(1, "notify err 0x%d",
 				pSMBr->hdr.Status.CifsError);
 			return true;
 		}
 		return false;
 	}
 	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 		return false;
 	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 		/* no sense logging error on invalid handle on oplock
 		   break - harmless race between close request and oplock
 		   break response is expected from time to time writing out
 		   large dirty files cached on the client */
 		if ((NT_STATUS_INVALID_HANDLE) ==
 		   le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 			cFYI(1, "invalid handle on oplock break");
 			return true;
 		} else if (ERRbadfid ==
 		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 			return true;
 		} else {
 			return false; /* on valid oplock brk we get "request" */
 		}
 	}
 	if (pSMB->hdr.WordCount != 8)
 		return false;

 	cFYI(1, "oplock type 0x%d level 0x%d",
 		 pSMB->LockType, pSMB->OplockLevel);
 	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 		return false;

 	/* look up tcon based on tid & uid */
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each(tmp, &srv->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);
 			if (tcon->tid != buf->Tid)
 				continue;

 			cifs_stats_inc(&tcon->num_oplock_brks);
 			spin_lock(&cifs_file_list_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				netfile = list_entry(tmp2, struct cifsFileInfo,
 						     tlist);
 				if (pSMB->Fid != netfile->netfid)
 					continue;

 				cFYI(1, "file id match, oplock break");
 				pCifsInode = CIFS_I(netfile->dentry->d_inode);

 				cifs_set_oplock_level(pCifsInode,
 					pSMB->OplockLevel ? OPLOCK_READ : 0);
 				queue_work(cifsiod_wq,
 					   &netfile->oplock_break);
 				netfile->oplock_break_cancelled = false;

 				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);
 			cFYI(1, "No matching file for oplock break");
 			return true;
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
 	cFYI(1, "Can not process oplock break for non-existent connection");
 	return true;
 }

 void
 dump_smb(void *buf, int smb_buf_length)
 {
 	int i, j;
 	char debug_line[17];
 	unsigned char *buffer = buf;

 	if (traceSMB == 0)
 		return;

 	for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
 		if (i % 8 == 0) {
 			/* have reached the beginning of line */
 			printk(KERN_DEBUG "| ");
 			j = 0;
 		}
 		printk("%0#4x ", buffer[i]);
 		debug_line[2 * j] = ' ';
 		if (isprint(buffer[i]))
 			debug_line[1 + (2 * j)] = buffer[i];
 		else
 			debug_line[1 + (2 * j)] = '_';

 		if (i % 8 == 7) {
 			/* reached end of line, time to print ascii */
 			debug_line[16] = 0;
 			printk(" | %s\n", debug_line);
 		}
 	}
 	for (; j < 8; j++) {
 		printk("     ");
 		debug_line[2 * j] = ' ';
 		debug_line[1 + (2 * j)] = ' ';
 	}
 	printk(" | %s\n", debug_line);
 	return;
 }

 void
 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 		cERROR(1, "Autodisabling the use of server inode numbers on "
 			   "%s. This server doesn't seem to support them "
 			   "properly. Hardlinks will not be recognized on this "
 			   "mount. Consider mounting with the \"noserverino\" "
 			   "option to silence this message.",
 			   cifs_sb_master_tcon(cifs_sb)->treeName);
 	}
 }

 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 {
 	oplock &= 0xF;

 	if (oplock == OPLOCK_EXCLUSIVE) {
 		cinode->clientCanCacheAll = true;
 		cinode->clientCanCacheRead = true;
 		cFYI(1, "Exclusive Oplock granted on inode %p",
 		     &cinode->vfs_inode);
 	} else if (oplock == OPLOCK_READ) {
 		cinode->clientCanCacheAll = false;
 		cinode->clientCanCacheRead = true;
 		cFYI(1, "Level II Oplock granted on inode %p",
 		    &cinode->vfs_inode);
 	} else {
 		cinode->clientCanCacheAll = false;
 		cinode->clientCanCacheRead = false;
 	}
 }

 bool
 backup_cred(struct cifs_sb_info *cifs_sb)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 		if (cifs_sb->mnt_backupuid == current_fsuid())
 			return true;
 	}
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 		if (in_group_p(cifs_sb->mnt_backupgid))
 			return true;
 	}

 	return false;
 }
	/*
	* fs/cifs/misc.c
	*
	* Copyright (C) International Business Machines Corp., 2002,2008
	* Author(s): Steve French (sfrench@us.ibm.com)
	*
	* 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/slab.h>
	#include <linux/ctype.h>
	#include <linux/mempool.h>
	#include "cifspdu.h"
	#include "cifsglob.h"
	#include "cifsproto.h"
	#include "cifs_debug.h"
	#include "smberr.h"
	#include "nterr.h"
	#include "cifs_unicode.h"

	extern mempool_t *cifs_sm_req_poolp;
	extern mempool_t *cifs_req_poolp;

	/* The xid serves as a useful identifier for each incoming vfs request,
	in a similar way to the mid which is useful to track each sent smb,
	and CurrentXid can also provide a running counter (although it
	will eventually wrap past zero) of the total vfs operations handled
	since the cifs fs was mounted */

	unsigned int
	_GetXid(void)
	{
	unsigned int xid;

	spin_lock(&GlobalMid_Lock);
	GlobalTotalActiveXid++;

	/* keep high water mark for number of simultaneous ops in filesystem */
	if (GlobalTotalActiveXid > GlobalMaxActiveXid)
	GlobalMaxActiveXid = GlobalTotalActiveXid;
	if (GlobalTotalActiveXid > 65000)
	cFYI(1, "warning: more than 65000 requests active");
	xid = GlobalCurrentXid++;
	spin_unlock(&GlobalMid_Lock);
	return xid;
	}

	void
	_FreeXid(unsigned int xid)
	{
	spin_lock(&GlobalMid_Lock);
	/* if (GlobalTotalActiveXid == 0)
	BUG(); */
	GlobalTotalActiveXid--;
	spin_unlock(&GlobalMid_Lock);
	}

	struct cifs_ses *
	sesInfoAlloc(void)
	{
	struct cifs_ses *ret_buf;

	ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
	if (ret_buf) {
	atomic_inc(&sesInfoAllocCount);
	ret_buf->status = CifsNew;
	++ret_buf->ses_count;
	INIT_LIST_HEAD(&ret_buf->smb_ses_list);
	INIT_LIST_HEAD(&ret_buf->tcon_list);
	mutex_init(&ret_buf->session_mutex);
	}
	return ret_buf;
	}

	void
	sesInfoFree(struct cifs_ses *buf_to_free)
	{
	if (buf_to_free == NULL) {
	cFYI(1, "Null buffer passed to sesInfoFree");
	return;
	}

	atomic_dec(&sesInfoAllocCount);
	kfree(buf_to_free->serverOS);
	kfree(buf_to_free->serverDomain);
	kfree(buf_to_free->serverNOS);
	if (buf_to_free->password) {
	memset(buf_to_free->password, 0, strlen(buf_to_free->password));
	kfree(buf_to_free->password);
	}
	kfree(buf_to_free->user_name);
	kfree(buf_to_free->domainName);
	kfree(buf_to_free);
	}

	struct cifs_tcon *
	tconInfoAlloc(void)
	{
	struct cifs_tcon *ret_buf;
	ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
	if (ret_buf) {
	atomic_inc(&tconInfoAllocCount);
	ret_buf->tidStatus = CifsNew;
	++ret_buf->tc_count;
	INIT_LIST_HEAD(&ret_buf->openFileList);
	INIT_LIST_HEAD(&ret_buf->tcon_list);
	#ifdef CONFIG_CIFS_STATS
	spin_lock_init(&ret_buf->stat_lock);
	#endif
	}
	return ret_buf;
	}

	void
	tconInfoFree(struct cifs_tcon *buf_to_free)
	{
	if (buf_to_free == NULL) {
	cFYI(1, "Null buffer passed to tconInfoFree");
	return;
	}
	atomic_dec(&tconInfoAllocCount);
	kfree(buf_to_free->nativeFileSystem);
	if (buf_to_free->password) {
	memset(buf_to_free->password, 0, strlen(buf_to_free->password));
	kfree(buf_to_free->password);
	}
	kfree(buf_to_free);
	}

	struct smb_hdr *
	cifs_buf_get(void)
	{
	struct smb_hdr *ret_buf = NULL;

	/* We could use negotiated size instead of max_msgsize -
	but it may be more efficient to always alloc same size
	albeit slightly larger than necessary and maxbuffersize
	defaults to this and can not be bigger */
	ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);

	/* clear the first few header bytes */
	/* for most paths, more is cleared in header_assemble */
	if (ret_buf) {
	memset(ret_buf, 0, sizeof(struct smb_hdr) + 3);
	atomic_inc(&bufAllocCount);
	#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&totBufAllocCount);
	#endif /* CONFIG_CIFS_STATS2 */
	}

	return ret_buf;
	}

	void
	cifs_buf_release(void *buf_to_free)
	{
	if (buf_to_free == NULL) {
	/* cFYI(1, "Null buffer passed to cifs_buf_release");*/
	return;
	}
	mempool_free(buf_to_free, cifs_req_poolp);

	atomic_dec(&bufAllocCount);
	return;
	}

	struct smb_hdr *
	cifs_small_buf_get(void)
	{
	struct smb_hdr *ret_buf = NULL;

	/* We could use negotiated size instead of max_msgsize -
	but it may be more efficient to always alloc same size
	albeit slightly larger than necessary and maxbuffersize
	defaults to this and can not be bigger */
	ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
	if (ret_buf) {
	/* No need to clear memory here, cleared in header assemble */
	/* memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
	atomic_inc(&smBufAllocCount);
	#ifdef CONFIG_CIFS_STATS2
	atomic_inc(&totSmBufAllocCount);
	#endif /* CONFIG_CIFS_STATS2 */

	}
	return ret_buf;
	}

	void
	cifs_small_buf_release(void *buf_to_free)
	{

	if (buf_to_free == NULL) {
	cFYI(1, "Null buffer passed to cifs_small_buf_release");
	return;
	}
	mempool_free(buf_to_free, cifs_sm_req_poolp);

	atomic_dec(&smBufAllocCount);
	return;
	}

	/*
	* Find a free multiplex id (SMB mid). Otherwise there could be
	* mid collisions which might cause problems, demultiplexing the
	* wrong response to this request. Multiplex ids could collide if
	* one of a series requests takes much longer than the others, or
	* if a very large number of long lived requests (byte range
	* locks or FindNotify requests) are pending. No more than
	* 64K-1 requests can be outstanding at one time. If no
	* mids are available, return zero. A future optimization
	* could make the combination of mids and uid the key we use
	* to demultiplex on (rather than mid alone).
	* In addition to the above check, the cifs demultiplex
	* code already used the command code as a secondary
	* check of the frame and if signing is negotiated the
	* response would be discarded if the mid were the same
	* but the signature was wrong. Since the mid is not put in the
	* pending queue until later (when it is about to be dispatched)
	* we do have to limit the number of outstanding requests
	* to somewhat less than 64K-1 although it is hard to imagine
	* so many threads being in the vfs at one time.
	*/
	__u64 GetNextMid(struct TCP_Server_Info *server)
	{
	__u64 mid = 0;
	__u16 last_mid, cur_mid;
	bool collision;

	spin_lock(&GlobalMid_Lock);

	/* mid is 16 bit only for CIFS/SMB */
	cur_mid = (__u16)((server->CurrentMid) & 0xffff);
	/* we do not want to loop forever */
	last_mid = cur_mid;
	cur_mid++;

	/*
	* This nested loop looks more expensive than it is.
	* In practice the list of pending requests is short,
	* fewer than 50, and the mids are likely to be unique
	* on the first pass through the loop unless some request
	* takes longer than the 64 thousand requests before it
	* (and it would also have to have been a request that
	* did not time out).
	*/
	while (cur_mid != last_mid) {
	struct mid_q_entry *mid_entry;
	unsigned int num_mids;

	collision = false;
	if (cur_mid == 0)
	cur_mid++;

	num_mids = 0;
	list_for_each_entry(mid_entry, &server->pending_mid_q, qhead) {
	++num_mids;
	if (mid_entry->mid == cur_mid &&
	mid_entry->mid_state == MID_REQUEST_SUBMITTED) {
	/* This mid is in use, try a different one */
	collision = true;
	break;
	}
	}

	/*
	* if we have more than 32k mids in the list, then something
	* is very wrong. Possibly a local user is trying to DoS the
	* box by issuing long-running calls and SIGKILL'ing them. If
	* we get to 2^16 mids then we're in big trouble as this
	* function could loop forever.
	*
	* Go ahead and assign out the mid in this situation, but force
	* an eventual reconnect to clean out the pending_mid_q.
	*/
	if (num_mids > 32768)
	server->tcpStatus = CifsNeedReconnect;

	if (!collision) {
	mid = (__u64)cur_mid;
	server->CurrentMid = mid;
	break;
	}
	cur_mid++;
	}
	spin_unlock(&GlobalMid_Lock);
	return mid;
	}

	/* NB: MID can not be set if treeCon not passed in, in that
	case it is responsbility of caller to set the mid */
	void
	header_assemble(struct smb_hdr buffer, char smb_command / command */ ,
	const struct cifs_tcon *treeCon, int word_count
	/* length of fixed section (word count) in two byte units */)
	{
	char temp = (char ) buffer;

	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */

	buffer->smb_buf_length = cpu_to_be32(
	(2 * word_count) + sizeof(struct smb_hdr) -
	4 /* RFC 1001 length field does not count */ +
	2 /* for bcc field itself */) ;

	buffer->Protocol[0] = 0xFF;
	buffer->Protocol[1] = 'S';
	buffer->Protocol[2] = 'M';
	buffer->Protocol[3] = 'B';
	buffer->Command = smb_command;
	buffer->Flags = 0x00; /* case sensitive */
	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
	buffer->Pid = cpu_to_le16((__u16)current->tgid);
	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
	if (treeCon) {
	buffer->Tid = treeCon->tid;
	if (treeCon->ses) {
	if (treeCon->ses->capabilities & CAP_UNICODE)
	buffer->Flags2 \|= SMBFLG2_UNICODE;
	if (treeCon->ses->capabilities & CAP_STATUS32)
	buffer->Flags2 \|= SMBFLG2_ERR_STATUS;

	/* Uid is not converted */
	buffer->Uid = treeCon->ses->Suid;
	buffer->Mid = GetNextMid(treeCon->ses->server);
	}
	if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
	buffer->Flags2 \|= SMBFLG2_DFS;
	if (treeCon->nocase)
	buffer->Flags \|= SMBFLG_CASELESS;
	if ((treeCon->ses) && (treeCon->ses->server))
	if (treeCon->ses->server->sec_mode &
	(SECMODE_SIGN_REQUIRED \| SECMODE_SIGN_ENABLED))
	buffer->Flags2 \|= SMBFLG2_SECURITY_SIGNATURE;
	}

	/* endian conversion of flags is now done just before sending */
	buffer->WordCount = (char) word_count;
	return;
	}

	static int
	check_smb_hdr(struct smb_hdr *smb, __u16 mid)
	{
	/* does it have the right SMB "signature" ? */
	if ((__le32 ) smb->Protocol != cpu_to_le32(0x424d53ff)) {
	cERROR(1, "Bad protocol string signature header 0x%x",
	(unsigned int )smb->Protocol);
	return 1;
	}

	/* Make sure that message ids match */
	if (mid != smb->Mid) {
	cERROR(1, "Mids do not match. received=%u expected=%u",
	smb->Mid, mid);
	return 1;
	}

	/* if it's a response then accept */
	if (smb->Flags & SMBFLG_RESPONSE)
	return 0;

	/* only one valid case where server sends us request */
	if (smb->Command == SMB_COM_LOCKING_ANDX)
	return 0;

	cERROR(1, "Server sent request, not response. mid=%u", smb->Mid);
	return 1;
	}

	int
	checkSMB(char *buf, unsigned int total_read)
	{
	struct smb_hdr smb = (struct smb_hdr )buf;
	__u16 mid = smb->Mid;
	__u32 rfclen = be32_to_cpu(smb->smb_buf_length);
	__u32 clc_len; /* calculated length */
	cFYI(0, "checkSMB Length: 0x%x, smb_buf_length: 0x%x",
	total_read, rfclen);

	/* is this frame too small to even get to a BCC? */
	if (total_read < 2 + sizeof(struct smb_hdr)) {
	if ((total_read >= sizeof(struct smb_hdr) - 1)
	&& (smb->Status.CifsError != 0)) {
	/* it's an error return */
	smb->WordCount = 0;
	/* some error cases do not return wct and bcc */
	return 0;
	} else if ((total_read == sizeof(struct smb_hdr) + 1) &&
	(smb->WordCount == 0)) {
	char tmp = (char )smb;
	/* Need to work around a bug in two servers here */
	/* First, check if the part of bcc they sent was zero */
	if (tmp[sizeof(struct smb_hdr)] == 0) {
	/* some servers return only half of bcc
	* on simple responses (wct, bcc both zero)
	* in particular have seen this on
	* ulogoffX and FindClose. This leaves
	* one byte of bcc potentially unitialized
	*/
	/* zero rest of bcc */
	tmp[sizeof(struct smb_hdr)+1] = 0;
	return 0;
	}
	cERROR(1, "rcvd invalid byte count (bcc)");
	} else {
	cERROR(1, "Length less than smb header size");
	}
	return -EIO;
	}

	/* otherwise, there is enough to get to the BCC */
	if (check_smb_hdr(smb, mid))
	return -EIO;
	clc_len = smbCalcSize(smb);

	if (4 + rfclen != total_read) {
	cERROR(1, "Length read does not match RFC1001 length %d",
	rfclen);
	return -EIO;
	}

	if (4 + rfclen != clc_len) {
	/* check if bcc wrapped around for large read responses */
	if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
	/* check if lengths match mod 64K */
	if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
	return 0; /* bcc wrapped */
	}
	cFYI(1, "Calculated size %u vs length %u mismatch for mid=%u",
	clc_len, 4 + rfclen, smb->Mid);

	if (4 + rfclen < clc_len) {
	cERROR(1, "RFC1001 size %u smaller than SMB for mid=%u",
	rfclen, smb->Mid);
	return -EIO;
	} else if (rfclen > clc_len + 512) {
	/*
	* Some servers (Windows XP in particular) send more
	* data than the lengths in the SMB packet would
	* indicate on certain calls (byte range locks and
	* trans2 find first calls in particular). While the
	* client can handle such a frame by ignoring the
	* trailing data, we choose limit the amount of extra
	* data to 512 bytes.
	*/
	cERROR(1, "RFC1001 size %u more than 512 bytes larger "
	"than SMB for mid=%u", rfclen, smb->Mid);
	return -EIO;
	}
	}
	return 0;
	}

	bool
	is_valid_oplock_break(char buffer, struct TCP_Server_Info srv)
	{
	struct smb_hdr buf = (struct smb_hdr )buffer;
	struct smb_com_lock_req pSMB = (struct smb_com_lock_req )buf;
	struct list_head tmp, tmp1, *tmp2;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct cifsInodeInfo *pCifsInode;
	struct cifsFileInfo *netfile;

	cFYI(1, "Checking for oplock break or dnotify response");
	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
	(pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
	struct smb_com_transaction_change_notify_rsp *pSMBr =
	(struct smb_com_transaction_change_notify_rsp *)buf;
	struct file_notify_information *pnotify;
	__u32 data_offset = 0;
	if (get_bcc(buf) > sizeof(struct file_notify_information)) {
	data_offset = le32_to_cpu(pSMBr->DataOffset);

	pnotify = (struct file_notify_information *)
	((char *)&pSMBr->hdr.Protocol + data_offset);
	cFYI(1, "dnotify on %s Action: 0x%x",
	pnotify->FileName, pnotify->Action);
	/* cifs_dump_mem("Rcvd notify Data: ",buf,
	sizeof(struct smb_hdr)+60); */
	return true;
	}
	if (pSMBr->hdr.Status.CifsError) {
	cFYI(1, "notify err 0x%d",
	pSMBr->hdr.Status.CifsError);
	return true;
	}
	return false;
	}
	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
	return false;
	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
	/* no sense logging error on invalid handle on oplock
	break - harmless race between close request and oplock
	break response is expected from time to time writing out
	large dirty files cached on the client */
	if ((NT_STATUS_INVALID_HANDLE) ==
	le32_to_cpu(pSMB->hdr.Status.CifsError)) {
	cFYI(1, "invalid handle on oplock break");
	return true;
	} else if (ERRbadfid ==
	le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
	return true;
	} else {
	return false; /* on valid oplock brk we get "request" */
	}
	}
	if (pSMB->hdr.WordCount != 8)
	return false;

	cFYI(1, "oplock type 0x%d level 0x%d",
	pSMB->LockType, pSMB->OplockLevel);
	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
	return false;

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each(tmp, &srv->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);
	if (tcon->tid != buf->Tid)
	continue;

	cifs_stats_inc(&tcon->num_oplock_brks);
	spin_lock(&cifs_file_list_lock);
	list_for_each(tmp2, &tcon->openFileList) {
	netfile = list_entry(tmp2, struct cifsFileInfo,
	tlist);
	if (pSMB->Fid != netfile->netfid)
	continue;

	cFYI(1, "file id match, oplock break");
	pCifsInode = CIFS_I(netfile->dentry->d_inode);

	cifs_set_oplock_level(pCifsInode,
	pSMB->OplockLevel ? OPLOCK_READ : 0);
	queue_work(cifsiod_wq,
	&netfile->oplock_break);
	netfile->oplock_break_cancelled = false;

	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);
	cFYI(1, "No matching file for oplock break");
	return true;
	}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	cFYI(1, "Can not process oplock break for non-existent connection");
	return true;
	}

	void
	dump_smb(void *buf, int smb_buf_length)
	{
	int i, j;
	char debug_line[17];
	unsigned char *buffer = buf;

	if (traceSMB == 0)
	return;

	for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
	if (i % 8 == 0) {
	/* have reached the beginning of line */
	printk(KERN_DEBUG "\| ");
	j = 0;
	}
	printk("%0#4x ", buffer[i]);
	debug_line[2 * j] = ' ';
	if (isprint(buffer[i]))
	debug_line[1 + (2 * j)] = buffer[i];
	else
	debug_line[1 + (2 * j)] = '_';

	if (i % 8 == 7) {
	/* reached end of line, time to print ascii */
	debug_line[16] = 0;
	printk(" \| %s\n", debug_line);
	}
	}
	for (; j < 8; j++) {
	printk(" ");
	debug_line[2 * j] = ' ';
	debug_line[1 + (2 * j)] = ' ';
	}
	printk(" \| %s\n", debug_line);
	return;
	}

	void
	cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
	{
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
	cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
	cERROR(1, "Autodisabling the use of server inode numbers on "
	"%s. This server doesn't seem to support them "
	"properly. Hardlinks will not be recognized on this "
	"mount. Consider mounting with the \"noserverino\" "
	"option to silence this message.",
	cifs_sb_master_tcon(cifs_sb)->treeName);
	}
	}

	void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
	{
	oplock &= 0xF;

	if (oplock == OPLOCK_EXCLUSIVE) {
	cinode->clientCanCacheAll = true;
	cinode->clientCanCacheRead = true;
	cFYI(1, "Exclusive Oplock granted on inode %p",
	&cinode->vfs_inode);
	} else if (oplock == OPLOCK_READ) {
	cinode->clientCanCacheAll = false;
	cinode->clientCanCacheRead = true;
	cFYI(1, "Level II Oplock granted on inode %p",
	&cinode->vfs_inode);
	} else {
	cinode->clientCanCacheAll = false;
	cinode->clientCanCacheRead = false;
	}
	}

	bool
	backup_cred(struct cifs_sb_info *cifs_sb)
	{
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
	if (cifs_sb->mnt_backupuid == current_fsuid())
	return true;
	}
	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
	if (in_group_p(cifs_sb->mnt_backupgid))
	return true;
	}

	return false;
	}