smb2misc.c

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/*
 *   fs/cifs/smb2misc.c
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2011
 *                 Etersoft, 2012
 *   Author(s): Steve French ([email protected])
 *              Pavel Shilovsky ([email protected]) 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
                cERROR(1, "Received Request not response");
        }
    } else { /* bad signature or mid */
        if (*(__le32 *)hdr->ProtocolId != SMB2_PROTO_NUMBER)
            cERROR(1, "Bad protocol string signature header %x",
                  *(unsigned int *) hdr->ProtocolId);
        if (mid != hdr->MessageId)
            cERROR(1, "Mids do not match: %llu and %llu", mid,
                  hdr->MessageId);
    }
    cERROR(1, "Bad SMB detected. The Mid=%llu", 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 */
    cFYI(1, "%s length: 0x%x, smb_buf_length: 0x%x", __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 {
            cERROR(1, "Length less than SMB header size");
        }
        return 1;
    }
    if (len > CIFSMaxBufSize + MAX_SMB2_HDR_SIZE - 4) {
        cERROR(1, "SMB length greater than maximum, mid=%llu", mid);
        return 1;
    }

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

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

    command = le16_to_cpu(hdr->Command);
    if (command >= NUMBER_OF_SMB2_COMMANDS) {
        cERROR(1, "Illegal SMB2 command %d", 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 */
            cERROR(1, "Illegal response size %u for command %d",
                   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 */
            cERROR(1, "Illegal response size %d for oplock break",
                   le16_to_cpu(pdu->StructureSize2));
            return 1;
        }
    }

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

    clc_len = smb2_calc_size(hdr);

    if (4 + len != clc_len) {
        cFYI(1, "Calculated size %u length %u mismatch mid %llu",
            clc_len, 4 + len, mid);
        /* 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 */
        if (clc_len == 4 + len + 1)
            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:
    case SMB2_CHANGE_NOTIFY:
    default:
        /* BB FIXME for unimplemented cases above */
        cERROR(1, "no length check for command");
        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) {
        cERROR(1, "offset %d too large, data area ignored", *off);
        *len = 0;
        *off = 0;
    } else if (*off < 0) {
        cERROR(1, "negative offset %d to data invalid ignore data area",
              *off);
        *off = 0;
        *len = 0;
    } else if (*len < 0) {
        cERROR(1, "negative data length %d invalid, data area ignored",
              *len);
        *len = 0;
    } else if (*len > 128 * 1024) {
        cERROR(1, "data area larger than 128K: %d", *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);
    cFYI(1, "SMB2 data length %d offset %d", 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) {
            cERROR(1, "data area offset %d overlaps SMB2 header %d",
                  offset + 4 + 1, len);
            data_length = 0;
        } else {
            len = 4 + offset + data_length;
        }
    }
calc_size_exit:
    cFYI(1, "SMB2 len %d", 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)
{
    if (cinode->clientCanCacheAll)
        return SMB2_LEASE_WRITE_CACHING | SMB2_LEASE_READ_CACHING;
    else if (cinode->clientCanCacheRead)
        return SMB2_LEASE_READ_CACHING;
    return 0;
}

__u8 smb2_map_lease_to_oplock(__le32 lease_state)
{
    if (lease_state & SMB2_LEASE_WRITE_CACHING) {
        if (lease_state & SMB2_LEASE_HANDLE_CACHING)
            return SMB2_OPLOCK_LEVEL_BATCH;
        else
            return SMB2_OPLOCK_LEVEL_EXCLUSIVE;
    } else if (lease_state & SMB2_LEASE_READ_CACHING)
        return SMB2_OPLOCK_LEVEL_II;
    return 0;
}

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);
    cFYI(1, "Lease release rc %d", rc);
    cifs_put_tlink(lw->tlink);
    kfree(lw);
}

static bool
smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
{
    struct smb2_lease_break *rsp = (struct smb2_lease_break *)buffer;
    struct list_head *tmp, *tmp1, *tmp2;
    struct cifs_ses *ses;
    struct cifs_tcon *tcon;
    struct cifsInodeInfo *cinode;
    struct cifsFileInfo *cfile;
    struct cifs_pending_open *open;
    struct smb2_lease_break_work *lw;
    bool found;
    int ack_req = le32_to_cpu(rsp->Flags &
                  SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED);

    lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
    if (!lw) {
        cERROR(1, "Memory allocation failed during lease break check");
        return false;
    }

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

    cFYI(1, "Checking for lease break");

    /* 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);

        spin_lock(&cifs_file_list_lock);
        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);
            list_for_each(tmp2, &tcon->openFileList) {
                cfile = list_entry(tmp2, struct cifsFileInfo,
                           tlist);
                cinode = CIFS_I(cfile->dentry->d_inode);

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

                cFYI(1, "found in the open list");
                cFYI(1, "lease key match, lease break 0x%d",
                     le32_to_cpu(rsp->NewLeaseState));

                smb2_set_oplock_level(cinode,
                  smb2_map_lease_to_oplock(rsp->NewLeaseState));

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

                queue_work(cifsiod_wq, &cfile->oplock_break);

                spin_unlock(&cifs_file_list_lock);
                spin_unlock(&cifs_tcp_ses_lock);
                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);
                }

                cFYI(1, "found in the pending open list");
                cFYI(1, "lease key match, lease break 0x%d",
                     le32_to_cpu(rsp->NewLeaseState));

                open->oplock =
                  smb2_map_lease_to_oplock(rsp->NewLeaseState);
            }
            if (found) {
                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);
    cFYI(1, "Can not process lease break - no lease matched");
    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;

    cFYI(1, "Checking for oplock break");

    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, server);
        else
            return false;
    }

    cFYI(1, "oplock level 0x%d", 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;

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

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

                smb2_set_oplock_level(cinode,
                  rsp->OplockLevel ? SMB2_OPLOCK_LEVEL_II : 0);

                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);
            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 false;
}