cifssmb.c

Linux内核自带的cifs模块

/*
 *   fs/cifs/cifssmb.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2007
 *   Author(s): Steve French ([e-mail])
 *
 *   Contains the routines for constructing the SMB PDUs themselves
 *
 *   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
 */

 /* SMB/CIFS PDU handling routines here - except for leftovers in connect.c   */
 /* These are mostly routines that operate on a pathname, or on a tree id     */
 /* (mounted volume), but there are eight handle based routines which must be */
 /* treated slightly differently for reconnection purposes since we never     */
 /* want to reuse a stale file handle and only the caller knows the file info */

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/vfs.h>
#include <linux/version.h>
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0)
#include <linux/posix_acl_xattr.h>
#endif
#include <asm/uaccess.h>
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_unicode.h"
#include "cifs_debug.h"
#include "cifsacl.h"

#ifdef CONFIG_CIFS_POSIX
static struct {
	int index;
	char *name;
} protocols[] = {
#ifdef CONFIG_CIFS_WEAK_PW_HASH
	{LANMAN_PROT, "\2LM1.2X002"},
	{LANMAN2_PROT, "\2LANMAN2.1"},
#endif /* weak password hashing for legacy clients */
	{CIFS_PROT, "\2NT LM 0.12"},
	{POSIX_PROT, "\2POSIX 2"},
	{BAD_PROT, "\2"}
};
#else
static struct {
	int index;
	char *name;
} protocols[] = {
#ifdef CONFIG_CIFS_WEAK_PW_HASH
	{LANMAN_PROT, "\2LM1.2X002"},
	{LANMAN2_PROT, "\2LANMAN2.1"},
#endif /* weak password hashing for legacy clients */
	{CIFS_PROT, "\2NT LM 0.12"},
	{BAD_PROT, "\2"}
};
#endif

/* define the number of elements in the cifs dialect array */
#ifdef CONFIG_CIFS_POSIX
#ifdef CONFIG_CIFS_WEAK_PW_HASH
#define CIFS_NUM_PROT 4
#else
#define CIFS_NUM_PROT 2
#endif /* CIFS_WEAK_PW_HASH */
#else /* not posix */
#ifdef CONFIG_CIFS_WEAK_PW_HASH
#define CIFS_NUM_PROT 3
#else
#define CIFS_NUM_PROT 1
#endif /* CONFIG_CIFS_WEAK_PW_HASH */
#endif /* CIFS_POSIX */


/* Mark as invalid, all open files on tree connections since they
   were closed when session to server was lost */
static void mark_open_files_invalid(struct cifsTconInfo *pTcon)
{
	struct cifsFileInfo *open_file = NULL;
	struct list_head *tmp;
	struct list_head *tmp1;

/* list all files open on tree connection and mark them invalid */
	write_lock(&GlobalSMBSeslock);
	list_for_each_safe(tmp, tmp1, &pTcon->openFileList) {
		open_file = list_entry(tmp, struct cifsFileInfo, tlist);
		if (open_file)
			open_file->invalidHandle = TRUE;
	}
	write_unlock(&GlobalSMBSeslock);
	/* BB Add call to invalidate_inodes(sb) for all superblocks mounted
	   to this tcon */
}

/* If the return code is zero, this function must fill in request_buf pointer */
static int
small_smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
	 void **request_buf /* returned */)
{
	int rc = 0;

	/* SMBs NegProt, SessSetup, uLogoff do not have tcon yet so
	   check for tcp and smb session status done differently
	   for those three - in the calling routine */
	if (tcon) {
		if (tcon->tidStatus == CifsExiting) {
			/* only tree disconnect, open, and write,
			(and ulogoff which does not have tcon)
			are allowed as we start force umount */
			if ((smb_command != SMB_COM_WRITE_ANDX) &&
			   (smb_command != SMB_COM_OPEN_ANDX) &&
			   (smb_command != SMB_COM_TREE_DISCONNECT)) {
				cFYI(1, ("can not send cmd %d while umounting",
					smb_command));
				return -ENODEV;
			}
		}
		if ((tcon->ses) && (tcon->ses->status != CifsExiting) &&
				  (tcon->ses->server)) {
			struct nls_table *nls_codepage;
				/* Give Demultiplex thread up to 10 seconds to
				   reconnect, should be greater than cifs socket
				   timeout which is 7 seconds */
			while(tcon->ses->server->tcpStatus == CifsNeedReconnect) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
				int timeout = 10 * HZ;
				while((tcon->ses->server->tcpStatus != CifsGood)
						&& (timeout > 0)) {
					timeout = interruptible_sleep_on_timeout(
						&tcon->ses->server->response_q,
						timeout);
				}
#else
				wait_event_interruptible_timeout(tcon->ses->server->response_q,
					(tcon->ses->server->tcpStatus == CifsGood), 10 * HZ);
#endif
				if (tcon->ses->server->tcpStatus == CifsNeedReconnect) {
					/* on "soft" mounts we wait once */
					if ((tcon->retry == FALSE) ||
					   (tcon->ses->status == CifsExiting)) {
						cFYI(1, ("gave up waiting on "
						      "reconnect in smb_init"));
						return -EHOSTDOWN;
					} /* else "hard" mount - keep retrying
					     until process is killed or server
					     comes back on-line */
				} else /* TCP session is reestablished now */
					break;
			}

			nls_codepage = load_nls_default();
		/* need to prevent multiple threads trying to
		simultaneously reconnect the same SMB session */
			down(&tcon->ses->sesSem);
			if (tcon->ses->status == CifsNeedReconnect)
				rc = cifs_setup_session(0, tcon->ses,
							nls_codepage);
			if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
				mark_open_files_invalid(tcon);
				rc = CIFSTCon(0, tcon->ses, tcon->treeName,
					      tcon, nls_codepage);
				up(&tcon->ses->sesSem);
				/* tell server which Unix caps we support */
				if (tcon->ses->capabilities & CAP_UNIX)
					reset_cifs_unix_caps(0 /* no xid */,
						tcon,
						NULL /* we do not know sb */,
						NULL /* no vol info */);
				/* BB FIXME add code to check if wsize needs
				   update due to negotiated smb buffer size
				   shrinking */
				if (rc == 0)
					atomic_inc(&tconInfoReconnectCount);

				cFYI(1, ("reconnect tcon rc = %d", rc));
				/* Removed call to reopen open files here.
				   It is safer (and faster) to reopen files
				   one at a time as needed in read and write */

				/* Check if handle based operation so we
				   know whether we can continue or not without
				   returning to caller to reset file handle */
				switch (smb_command) {
					case SMB_COM_READ_ANDX:
					case SMB_COM_WRITE_ANDX:
					case SMB_COM_CLOSE:
					case SMB_COM_FIND_CLOSE2:
					case SMB_COM_LOCKING_ANDX: {
						unload_nls(nls_codepage);
						return -EAGAIN;
					}
				}
			} else {
				up(&tcon->ses->sesSem);
			}
			unload_nls(nls_codepage);

		} else {
			return -EIO;
		}
	}
	if (rc)
		return rc;

	*request_buf = cifs_small_buf_get();
	if (*request_buf == NULL) {
		/* BB should we add a retry in here if not a writepage? */
		return -ENOMEM;
	}

	header_assemble((struct smb_hdr *) *request_buf, smb_command,
			tcon, wct);

	if (tcon != NULL)
		cifs_stats_inc(&tcon->num_smbs_sent);

	return rc;
}

int
small_smb_init_no_tc(const int smb_command, const int wct,
		     struct cifsSesInfo *ses, void **request_buf)
{
	int rc;
	struct smb_hdr *buffer;

	rc = small_smb_init(smb_command, wct, NULL, request_buf);
	if (rc)
		return rc;

	buffer = (struct smb_hdr *)*request_buf;
	buffer->Mid = GetNextMid(ses->server);
	if (ses->capabilities & CAP_UNICODE)
		buffer->Flags2 |= SMBFLG2_UNICODE;
	if (ses->capabilities & CAP_STATUS32)
		buffer->Flags2 |= SMBFLG2_ERR_STATUS;

	/* uid, tid can stay at zero as set in header assemble */

	/* BB add support for turning on the signing when
	this function is used after 1st of session setup requests */

	return rc;
}

/* If the return code is zero, this function must fill in request_buf pointer */
static int
smb_init(int smb_command, int wct, struct cifsTconInfo *tcon,
	 void **request_buf /* returned */ ,
	 void **response_buf /* returned */ )
{
	int rc = 0;

	/* SMBs NegProt, SessSetup, uLogoff do not have tcon yet so
	   check for tcp and smb session status done differently
	   for those three - in the calling routine */
	if (tcon) {
		if (tcon->tidStatus == CifsExiting) {
			/* only tree disconnect, open, and write,
			  (and ulogoff which does not have tcon)
			  are allowed as we start force umount */
			if ((smb_command != SMB_COM_WRITE_ANDX) &&
			   (smb_command != SMB_COM_OPEN_ANDX) &&
			   (smb_command != SMB_COM_TREE_DISCONNECT)) {
				cFYI(1, ("can not send cmd %d while umounting",
					smb_command));
				return -ENODEV;
			}
		}

		if ((tcon->ses) && (tcon->ses->status != CifsExiting) &&
				  (tcon->ses->server)) {
			struct nls_table *nls_codepage;
				/* Give Demultiplex thread up to 10 seconds to
				   reconnect, should be greater than cifs socket
				   timeout which is 7 seconds */
			while(tcon->ses->server->tcpStatus == CifsNeedReconnect) {
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)
				int timeout = 10 * HZ;
				while((tcon->ses->server->tcpStatus != CifsGood)
						&& (timeout > 0)) {
					timeout = interruptible_sleep_on_timeout
						(&tcon->ses->server->response_q,
						 timeout);
				}
#else
				wait_event_interruptible_timeout(tcon->ses->server->response_q,
					(tcon->ses->server->tcpStatus == CifsGood), 10 * HZ);
#endif
				if (tcon->ses->server->tcpStatus ==
						CifsNeedReconnect) {
					/* on "soft" mounts we wait once */
					if ((tcon->retry == FALSE) ||
					   (tcon->ses->status == CifsExiting)) {
						cFYI(1, ("gave up waiting on "
						      "reconnect in smb_init"));
						return -EHOSTDOWN;
					} /* else "hard" mount - keep retrying
					     until process is killed or server
					     comes on-line */
				} else /* TCP session is reestablished now */
					break;
			}
			nls_codepage = load_nls_default();
		/* need to prevent multiple threads trying to
		simultaneously reconnect the same SMB session */
			down(&tcon->ses->sesSem);
			if (tcon->ses->status == CifsNeedReconnect)
				rc = cifs_setup_session(0, tcon->ses,
							nls_codepage);
			if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
				mark_open_files_invalid(tcon);
				rc = CIFSTCon(0, tcon->ses, tcon->treeName,
					      tcon, nls_codepage);
				up(&tcon->ses->sesSem);
				/* tell server which Unix caps we support */
				if (tcon->ses->capabilities & CAP_UNIX)
					reset_cifs_unix_caps(0 /* no xid */,
						tcon,
						NULL /* do not know sb */,
						NULL /* no vol info */);
				/* BB FIXME add code to check if wsize needs
				update due to negotiated smb buffer size
				shrinking */
				if (rc == 0)
					atomic_inc(&tconInfoReconnectCount);

				cFYI(1, ("reconnect tcon rc = %d", rc));
				/* Removed call to reopen open files here.
				   It is safer (and faster) to reopen files
				   one at a time as needed in read and write */

				/* Check if handle based operation so we
				   know whether we can continue or not without
				   returning to caller to reset file handle */
				switch (smb_command) {
					case SMB_COM_READ_ANDX:
					case SMB_COM_WRITE_ANDX:
					case SMB_COM_CLOSE:
					case SMB_COM_FIND_CLOSE2:
					case SMB_COM_LOCKING_ANDX: {
						unload_nls(nls_codepage);
						return -EAGAIN;
					}
				}
			} else {
				up(&tcon->ses->sesSem);
			}
			unload_nls(nls_codepage);

		} else {
			return -EIO;
		}
	}
	if (rc)
		return rc;

	*request_buf = cifs_buf_get();
	if (*request_buf == NULL) {
		/* BB should we add a retry in here if not a writepage? */
		return -ENOMEM;
	}
    /* Although the original thought was we needed the response buf for  */
    /* potential retries of smb operations it turns out we can determine */
    /* from the mid flags when the request buffer can be resent without  */
    /* having to use a second distinct buffer for the response */
	if (response_buf)
		*response_buf = *request_buf;

	header_assemble((struct smb_hdr *) *request_buf, smb_command, tcon,
			wct /*wct */ );

	if (tcon != NULL)
		cifs_stats_inc(&tcon->num_smbs_sent);

	return rc;
}

static int validate_t2(struct smb_t2_rsp *pSMB)
{
	int rc = -EINVAL;
	int total_size;
	char *pBCC;

	/* check for plausible wct, bcc and t2 data and parm sizes */
	/* check for parm and data offset going beyond end of smb */
	if (pSMB->hdr.WordCount >= 10) {
		if ((le16_to_cpu(pSMB->t2_rsp.ParameterOffset) <= 1024) &&
		   (le16_to_cpu(pSMB->t2_rsp.DataOffset) <= 1024)) {
			/* check that bcc is at least as big as parms + data */
			/* check that bcc is less than negotiated smb buffer */
			total_size = le16_to_cpu(pSMB->t2_rsp.ParameterCount);
			if (total_size < 512) {
				total_size +=
					le16_to_cpu(pSMB->t2_rsp.DataCount);
				/* BCC le converted in SendReceive */
				pBCC = (pSMB->hdr.WordCount * 2) +
					sizeof(struct smb_hdr) +
					(char *)pSMB;
				if ((total_size <= (*(u16 *)pBCC)) &&
				   (total_size <
					CIFSMaxBufSize+MAX_CIFS_HDR_SIZE)) {
					return 0;
				}
			}
		}
	}
	cifs_dump_mem("Invalid transact2 SMB: ", (char *)pSMB,
		sizeof(struct smb_t2_rsp) + 16);
	return rc;
}
int
CIFSSMBNegotiate(unsigned int xid, struct cifsSesInfo *ses)
{
	NEGOTIATE_REQ *pSMB;
	NEGOTIATE_RSP *pSMBr;
	int rc = 0;
	int bytes_returned;
	int i;
	struct TCP_Server_Info *server;