misc.c

Go to the documentation of this file.

/*
 *   fs/cifs/misc.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French ([email protected])
 *
 *   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"
#ifdef CONFIG_CIFS_SMB2
#include "smb2pdu.h"
#endif

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
_get_xid(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
_free_xid(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;
    size_t buf_size = sizeof(struct smb_hdr);

#ifdef CONFIG_CIFS_SMB2
    /*
     * SMB2 header is bigger than CIFS one - no problems to clean some
     * more bytes for CIFS.
     */
    buf_size = sizeof(struct smb2_hdr);
#endif
    /*
     * 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, buf_size + 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;
}

/* 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 = get_next_mid(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->stats.cifs_stats.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->fid.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_del_pending_open(struct cifs_pending_open *open)
{
    spin_lock(&cifs_file_list_lock);
    list_del(&open->olist);
    spin_unlock(&cifs_file_list_lock);
}

void
cifs_add_pending_open_locked(struct cifs_fid *fid, struct tcon_link *tlink,
                 struct cifs_pending_open *open)
{
#ifdef CONFIG_CIFS_SMB2
    memcpy(open->lease_key, fid->lease_key, SMB2_LEASE_KEY_SIZE);
#endif
    open->oplock = CIFS_OPLOCK_NO_CHANGE;
    open->tlink = tlink;
    fid->pending_open = open;
    list_add_tail(&open->olist, &tlink_tcon(tlink)->pending_opens);
}

void
cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
              struct cifs_pending_open *open)
{
    spin_lock(&cifs_file_list_lock);
    cifs_add_pending_open_locked(fid, tlink, open);
    spin_unlock(&cifs_file_list_lock);
}