- 根目录:
- fs
- cifs
- misc.c
/*
* 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 */)
{
struct list_head *temp_item;
struct cifs_ses *ses;
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 (multiuser_mount != 0) {
/* For the multiuser case, there are few obvious technically */
/* possible mechanisms to match the local linux user (uid) */
/* to a valid remote smb user (smb_uid): */
/* 1) Query Winbind (or other local pam/nss daemon */
/* for userid/password/logon_domain or credential */
/* 2) Query Winbind for uid to sid to username mapping */
/* and see if we have a matching password for existing*/
/* session for that user perhas getting password by */
/* adding a new pam_cifs module that stores passwords */
/* so that the cifs vfs can get at that for all logged*/
/* on users */
/* 3) (Which is the mechanism we have chosen) */
/* Search through sessions to the same server for a */
/* a match on the uid that was passed in on mount */
/* with the current processes uid (or euid?) and use */
/* that smb uid. If no existing smb session for */
/* that uid found, use the default smb session ie */
/* the smb session for the volume mounted which is */
/* the same as would be used if the multiuser mount */
/* flag were disabled. */
/* BB Add support for establishing new tCon and SMB Session */
/* with userid/password pairs found on the smb session */
/* for other target tcp/ip addresses BB */
if (current_fsuid() != treeCon->ses->linux_uid) {
cFYI(1, "Multiuser mode and UID "
"did not match tcon uid");
spin_lock(&cifs_tcp_ses_lock);
list_for_each(temp_item, &treeCon->ses->server->smb_ses_list) {
ses = list_entry(temp_item, struct cifs_ses, smb_ses_list);
if (ses->linux_uid == current_fsuid()) {
if (ses->server == treeCon->ses->server) {
cFYI(1, "found matching uid substitute right smb_uid");
buffer->Uid = ses->Suid;
break;
} else {
/* BB eventually call cifs_setup_session here */
cFYI(1, "local UID found but no smb sess with this server exists");
}
}
}
spin_unlock(&cifs_tcp_ses_lock);
}
}
}
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;
}
void
cifs_add_credits(struct TCP_Server_Info *server, const unsigned int add)
{
spin_lock(&server->req_lock);
server->credits += add;
server->in_flight--;
spin_unlock(&server->req_lock);
wake_up(&server->request_q);
}
void
cifs_set_credits(struct TCP_Server_Info *server, const int val)
{
spin_lock(&server->req_lock);
server->credits = val;
server->oplocks = val > 1 ? enable_oplocks : false;
spin_unlock(&server->req_lock);
}