fs/smbsrv/smb2_lock.c

/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
 */

/*
 * Dispatch function for SMB2_LOCK
 */

#include <smbsrv/smb2_kproto.h>

struct SMB2_LOCK_ELEMENT {
    uint64_t Offset;
    uint64_t Length;
    uint32_t Flags;
    uint32_t reserved;
};

static smb_sdrc_t smb2_lock_async(smb_request_t *);
static uint32_t smb2_lock_exec(smb_request_t *, uint16_t);
static uint32_t smb2_lock_elem(smb_request_t *, struct SMB2_LOCK_ELEMENT *);

/*
 * This is a somewhat arbitrary sanity limit on the length of the
 * SMB2_LOCK_ELEMENT array.  It usually has length one or two.
 */
int smb2_lock_max_elem = 1024;

smb_sdrc_t
smb2_lock(smb_request_t *sr)
{
    struct SMB2_LOCK_ELEMENT elem;
    smb2fid_t smb2fid;
    uint32_t save_offset;
    uint32_t LockSequence;
    uint32_t status;
    uint16_t StructSize;
    uint16_t LockCount;
    uint16_t i;
    boolean_t MayBlock = B_FALSE;
    int rc = 0;

    /*
     * SMB2 Lock request
     */
    rc = smb_mbc_decodef(
        &sr->smb_data, "wwlqq",
        &StructSize,        /* w */
        &LockCount,         /* w */
        &LockSequence,      /* l */
        &smb2fid.persistent,    /* q */
        &smb2fid.temporal);     /* q */
    if (rc || StructSize != 48)
        return (SDRC_ERROR);

    status = smb2sr_lookup_fid(sr, &smb2fid);
    if (status)
        goto errout;
    if (sr->fid_ofile->f_node == NULL || LockCount == 0) {
        status = NT_STATUS_INVALID_PARAMETER;
        goto errout;
    }
    if (LockCount > smb2_lock_max_elem) {
        status = NT_STATUS_INSUFFICIENT_RESOURCES;
        goto errout;
    }

    /*
     * Process the array of SMB2_LOCK_ELEMENT structs
     * We do this twice.  (it's always a short list)
     * The first time, just validate the flags, and check
     * if any of the locking request might need to block.
     * The second time (either here, or in the async
     * handler function) process the locks for real.
     */
    save_offset = sr->smb_data.chain_offset;
    for (i = 0; i < LockCount; i++) {
        rc = smb_mbc_decodef(
            &sr->smb_data, "qqll",
            &elem.Offset,   /* q */
            &elem.Length,   /* q */
            &elem.Flags,    /* l */
            &elem.reserved);    /* l */
        if (rc) {
            status = NT_STATUS_INVALID_PARAMETER;
            goto errout;
        }

        /*
         * Make sure the flags are valid;
         * Find out if we might block.
         */
        switch (elem.Flags) {
        case SMB2_LOCKFLAG_SHARED_LOCK:
        case SMB2_LOCKFLAG_EXCLUSIVE_LOCK:
            MayBlock = B_TRUE;
            break;

        /* BEGIN CSTYLED */
        case SMB2_LOCKFLAG_SHARED_LOCK |
             SMB2_LOCKFLAG_FAIL_IMMEDIATELY:
        case SMB2_LOCKFLAG_EXCLUSIVE_LOCK |
             SMB2_LOCKFLAG_FAIL_IMMEDIATELY:
        case SMB2_LOCKFLAG_UNLOCK:
        /* END CSTYLED */
            break;

        default:
            status = NT_STATUS_INVALID_PARAMETER;
            goto errout;
        }
    }

    if (MayBlock) {
        /*
         * May need to block.  "Go async".
         */
        status = smb2sr_go_async(sr, smb2_lock_async);
        goto errout;
    }

    sr->smb_data.chain_offset = save_offset;
    status = smb2_lock_exec(sr, LockCount);
    if (status)
        goto errout;

    /*
     * SMB2 Lock reply (sync)
     */
    StructSize = 4;
    (void) smb_mbc_encodef(
        &sr->reply, "w..",
        StructSize);    /* w */
        /* reserved       .. */
    return (SDRC_SUCCESS);

errout:
    smb2sr_put_error(sr, status);
    return (SDRC_SUCCESS);
}

static smb_sdrc_t
smb2_lock_async(smb_request_t *sr)
{
    smb2fid_t smb2fid;
    uint32_t LockSequence;
    uint32_t status;
    uint16_t StructSize;
    uint16_t LockCount;
    int rc = 0;

    /*
     * Decode the lock request again.  It should all decode
     * exactly the same as the first time we saw it.  If not,
     * report an "internal error".
     */
    rc = smb_mbc_decodef(
        &sr->smb_data, "wwlqq",
        &StructSize,        /* w */
        &LockCount,         /* w */
        &LockSequence,      /* l */
        &smb2fid.persistent,    /* q */
        &smb2fid.temporal);     /* q */
    if (rc || StructSize != 48)
        return (SDRC_ERROR);

    status = smb2sr_lookup_fid(sr, &smb2fid);
    if (status)
        goto errout;
    if (sr->fid_ofile->f_node == NULL || LockCount == 0) {
        status = NT_STATUS_INTERNAL_ERROR;
        goto errout;
    }

    status = smb2_lock_exec(sr, LockCount);
    if (status)
        goto errout;

    /*
     * SMB2 Lock reply (async)
     */
    StructSize = 4;
    (void) smb_mbc_encodef(
        &sr->reply, "w..",
        StructSize);    /* w */
        /* reserved       .. */
    return (SDRC_SUCCESS);

errout:
    smb2sr_put_error(sr, status);
    return (SDRC_SUCCESS);
}

/*
 * Execute the vector of locks.  This is the common function called by
 * either the sync or async code paths.  We've already decoded this
 * request once when we get here, so if there are any decode errors
 * then it's some kind of internal error.
 */
static uint32_t
smb2_lock_exec(smb_request_t *sr, uint16_t LockCount)
{
    struct SMB2_LOCK_ELEMENT elem;
    uint32_t status = 0;
    uint16_t i;
    int rc;

    /*
     * On entry, out position in the input data should be
     * after both the SMB2 header and the fixed part of
     * the SMB Lock request header (24).
     */
    ASSERT(sr->smb_data.chain_offset ==
        (sr->smb2_cmd_hdr + SMB2_HDR_SIZE + 24));

    /*
     * This is checked by our callers, but let's make sure.
     */
    ASSERT(sr->fid_ofile->f_node != NULL);

    for (i = 0; i < LockCount; i++) {
        rc = smb_mbc_decodef(
            &sr->smb_data, "qqll",
            &elem.Offset,   /* q */
            &elem.Length,   /* q */
            &elem.Flags,    /* l */
            &elem.reserved);    /* l */
        if (rc) {
            status = NT_STATUS_INTERNAL_ERROR;
            break;
        }
        status = smb2_lock_elem(sr, &elem);
        if (status)
            break;
    }
    return (status);
}

static uint32_t
smb2_lock_elem(smb_request_t *sr, struct SMB2_LOCK_ELEMENT *elem)
{
    smb_node_t *node = sr->fid_ofile->f_node;
    uint32_t status;
    uint32_t ltype;
    uint32_t timeout = 0;

    switch (elem->Flags) {
    case SMB2_LOCKFLAG_SHARED_LOCK:
        timeout = UINT_MAX;
        /* FALLTHROUGH */
    case SMB2_LOCKFLAG_SHARED_LOCK | SMB2_LOCKFLAG_FAIL_IMMEDIATELY:
        ltype = SMB_LOCK_TYPE_READONLY;
        status = smb_lock_range(sr,
            elem->Offset, elem->Length,
            timeout, ltype);
        break;

    case SMB2_LOCKFLAG_EXCLUSIVE_LOCK:
        timeout = UINT_MAX;
        /* FALLTHROUGH */
    case SMB2_LOCKFLAG_EXCLUSIVE_LOCK | SMB2_LOCKFLAG_FAIL_IMMEDIATELY:
        ltype = SMB_LOCK_TYPE_READWRITE;
        status = smb_lock_range(sr,
            elem->Offset, elem->Length,
            timeout, ltype);
        break;

    case SMB2_LOCKFLAG_UNLOCK:
        status = smb_unlock_range(sr, node,
            elem->Offset, elem->Length);
        break;

    /*
     * We've already checked the flags previously, so any
     * surprises here are some kind of internal error.
     */
    default:
        status = NT_STATUS_INTERNAL_ERROR;
        break;
    }

    return (status);
}