libsmb/common/smb_sd.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * This module provides Security Descriptor handling functions.
 */

#include <strings.h>
#include <assert.h>
#include <errno.h>
#include <smbsrv/ntifs.h>
#include <smbsrv/smb_idmap.h>
#include <smbsrv/libsmb.h>

#define SMB_SHR_ACE_READ_PERMS  (ACE_READ_PERMS | ACE_EXECUTE | ACE_SYNCHRONIZE)
#define SMB_SHR_ACE_CONTROL_PERMS   (ACE_MODIFY_PERMS & (~ACE_DELETE_CHILD))

/*
 * This mapping table is provided to map permissions set by chmod
 * using 'read_set' and 'modify_set' to what Windows share ACL GUI
 * expects as Read and Control, respectively.
 */
static struct {
    int am_ace_perms;
    int am_share_perms;
} smb_ace_map[] = {
    { ACE_MODIFY_PERMS, SMB_SHR_ACE_CONTROL_PERMS },
    { ACE_READ_PERMS,   SMB_SHR_ACE_READ_PERMS }
};

#define SMB_ACE_MASK_MAP_SIZE   (sizeof (smb_ace_map)/sizeof (smb_ace_map[0]))

static void smb_sd_set_sacl(smb_sd_t *, smb_acl_t *, boolean_t, int);
static void smb_sd_set_dacl(smb_sd_t *, smb_acl_t *, boolean_t, int);

void
smb_sd_init(smb_sd_t *sd, uint8_t revision)
{
    bzero(sd, sizeof (smb_sd_t));
    sd->sd_revision = revision;
}

/*
 * smb_sd_term
 *
 * Free non-NULL members of 'sd' which has to be in
 * absolute (pointer) form.
 */
void
smb_sd_term(smb_sd_t *sd)
{
    assert(sd);
    assert((sd->sd_control & SE_SELF_RELATIVE) == 0);

    smb_sid_free(sd->sd_owner);
    smb_sid_free(sd->sd_group);
    smb_acl_free(sd->sd_dacl);
    smb_acl_free(sd->sd_sacl);

    bzero(sd, sizeof (smb_sd_t));
}

uint32_t
smb_sd_len(smb_sd_t *sd, uint32_t secinfo)
{
    uint32_t length = SMB_SD_HDRSIZE;

    if (secinfo & SMB_OWNER_SECINFO)
        length += smb_sid_len(sd->sd_owner);

    if (secinfo & SMB_GROUP_SECINFO)
        length += smb_sid_len(sd->sd_group);

    if (secinfo & SMB_DACL_SECINFO)
        length += smb_acl_len(sd->sd_dacl);

    if (secinfo & SMB_SACL_SECINFO)
        length += smb_acl_len(sd->sd_sacl);

    return (length);
}

/*
 * smb_sd_get_secinfo
 *
 * Return the security information mask for the specified security
 * descriptor.
 */
uint32_t
smb_sd_get_secinfo(smb_sd_t *sd)
{
    uint32_t sec_info = 0;

    if (sd == NULL)
        return (0);

    if (sd->sd_owner)
        sec_info |= SMB_OWNER_SECINFO;

    if (sd->sd_group)
        sec_info |= SMB_GROUP_SECINFO;

    if (sd->sd_dacl)
        sec_info |= SMB_DACL_SECINFO;

    if (sd->sd_sacl)
        sec_info |= SMB_SACL_SECINFO;

    return (sec_info);
}

/*
 * Adjust the Access Mask so that ZFS ACE mask and Windows ACE read mask match.
 */
static int
smb_sd_adjust_read_mask(int mask)
{
    int i;

    for (i = 0; i < SMB_ACE_MASK_MAP_SIZE; ++i) {
        if (smb_ace_map[i].am_ace_perms == mask)
            return (smb_ace_map[i].am_share_perms);
    }

    return (mask);
}

/*
 * Get ZFS acl from the share path via acl_get() method.
 */
static uint32_t
smb_sd_read_acl(char *path, smb_fssd_t *fs_sd)
{
    acl_t *z_acl;
    ace_t *z_ace;

    fs_sd->sd_gid = fs_sd->sd_uid = 0;

    errno = 0;
    if (acl_get(path, 0, &z_acl) != 0) {
        switch (errno) {
        case EACCES:
            return (NT_STATUS_ACCESS_DENIED);
        case ENOENT:
            return (NT_STATUS_OBJECT_PATH_NOT_FOUND);
        default:
            return (NT_STATUS_INTERNAL_ERROR);
        }
    }

    if ((z_ace = (ace_t *)z_acl->acl_aclp) == NULL)
        return (NT_STATUS_INVALID_ACL);

    for (int i = 0; i < z_acl->acl_cnt; i++, z_ace++)
        z_ace->a_access_mask =
            smb_sd_adjust_read_mask(z_ace->a_access_mask);

    fs_sd->sd_zdacl = z_acl;
    fs_sd->sd_zsacl = NULL;
    return (NT_STATUS_SUCCESS);
}

/*
 * smb_sd_read
 *
 * Reads ZFS acl from filesystem using acl_get() method. Convert the ZFS acl to
 * a Win SD and return the Win SD in absolute form.
 *
 * NOTE: upon successful return caller MUST free the memory allocated
 * for the returned SD by calling smb_sd_term().
 */
uint32_t
smb_sd_read(char *path, smb_sd_t *sd, uint32_t secinfo)
{
    smb_fssd_t fs_sd;
    uint32_t status = NT_STATUS_SUCCESS;
    uint32_t sd_flags;
    int error;

    sd_flags = SMB_FSSD_FLAGS_DIR;
    smb_fssd_init(&fs_sd, secinfo, sd_flags);

    error = smb_sd_read_acl(path, &fs_sd);
    if (error != NT_STATUS_SUCCESS) {
        smb_fssd_term(&fs_sd);
        return (error);
    }

    status = smb_sd_fromfs(&fs_sd, sd);
    smb_fssd_term(&fs_sd);

    return (status);
}

/*
 * Apply ZFS acl to the share path via acl_set() method.
 * A NULL ACL pointer here represents an error.
 * Null or empty ACLs are handled in smb_sd_tofs().
 */
static uint32_t
smb_sd_write_acl(char *path, smb_fssd_t *fs_sd)
{
    acl_t *z_acl;
    ace_t *z_ace;
    uint32_t status = NT_STATUS_SUCCESS;

    z_acl = fs_sd->sd_zdacl;
    if (z_acl == NULL)
        return (NT_STATUS_INVALID_ACL);

    z_ace = (ace_t *)z_acl->acl_aclp;
    if (z_ace == NULL)
        return (NT_STATUS_INVALID_ACL);

    fs_sd->sd_gid = fs_sd->sd_uid = 0;
    if (acl_set(path, z_acl) != 0)
        status = NT_STATUS_INTERNAL_ERROR;

    return (status);
}

/*
 * smb_sd_write
 *
 * Takes a Win SD in absolute form, converts it to
 * ZFS acl and applies the acl to the share path via acl_set() method.
 */
uint32_t
smb_sd_write(char *path, smb_sd_t *sd, uint32_t secinfo)
{
    smb_fssd_t fs_sd;
    uint32_t status = NT_STATUS_SUCCESS;
    uint32_t sd_flags;
    int error;

    sd_flags = SMB_FSSD_FLAGS_DIR;
    smb_fssd_init(&fs_sd, secinfo, sd_flags);

    error = smb_sd_tofs(sd, &fs_sd);
    if (error != NT_STATUS_SUCCESS) {
        smb_fssd_term(&fs_sd);
        return (error);
    }

    status = smb_sd_write_acl(path, &fs_sd);
    smb_fssd_term(&fs_sd);

    return (status);
}

/*
 * smb_sd_tofs
 *
 * Creates a filesystem security structure based on the given
 * Windows security descriptor.
 */
uint32_t
smb_sd_tofs(smb_sd_t *sd, smb_fssd_t *fs_sd)
{
    smb_sid_t *sid;
    uint32_t status = NT_STATUS_SUCCESS;
    uint16_t sd_control;
    idmap_stat idm_stat;
    int idtype;
    int flags = 0;

    sd_control = sd->sd_control;

    /*
     * ZFS only has one set of flags so for now only
     * Windows DACL flags are taken into account.
     */
    if (sd_control & SE_DACL_DEFAULTED)
        flags |= ACL_DEFAULTED;
    if (sd_control & SE_DACL_AUTO_INHERITED)
        flags |= ACL_AUTO_INHERIT;
    if (sd_control & SE_DACL_PROTECTED)
        flags |= ACL_PROTECTED;

    if (fs_sd->sd_flags & SMB_FSSD_FLAGS_DIR)
        flags |= ACL_IS_DIR;

    /* Owner */
    if (fs_sd->sd_secinfo & SMB_OWNER_SECINFO) {
        sid = sd->sd_owner;
        if (!smb_sid_isvalid(sid))
            return (NT_STATUS_INVALID_SID);

        idtype = SMB_IDMAP_USER;
        idm_stat = smb_idmap_getid(sid, &fs_sd->sd_uid, &idtype);
        if (idm_stat != IDMAP_SUCCESS) {
            return (NT_STATUS_NONE_MAPPED);
        }
    }

    /* Group */
    if (fs_sd->sd_secinfo & SMB_GROUP_SECINFO) {
        sid = sd->sd_group;
        if (!smb_sid_isvalid(sid))
            return (NT_STATUS_INVALID_SID);

        idtype = SMB_IDMAP_GROUP;
        idm_stat = smb_idmap_getid(sid, &fs_sd->sd_gid, &idtype);
        if (idm_stat != IDMAP_SUCCESS) {
            return (NT_STATUS_NONE_MAPPED);
        }
    }

    /* DACL */
    if (fs_sd->sd_secinfo & SMB_DACL_SECINFO) {
        if (sd->sd_control & SE_DACL_PRESENT) {
            status = smb_acl_to_zfs(sd->sd_dacl, flags,
                SMB_DACL_SECINFO, &fs_sd->sd_zdacl);
            if (status != NT_STATUS_SUCCESS)
                return (status);
        }
        else
            return (NT_STATUS_INVALID_ACL);
    }

    /* SACL */
    if (fs_sd->sd_secinfo & SMB_SACL_SECINFO) {
        if (sd->sd_control & SE_SACL_PRESENT) {
            status = smb_acl_to_zfs(sd->sd_sacl, flags,
                SMB_SACL_SECINFO, &fs_sd->sd_zsacl);
            if (status != NT_STATUS_SUCCESS) {
                return (status);
            }
        } else {
            return (NT_STATUS_INVALID_ACL);
        }
    }

    return (status);
}

/*
 * smb_sd_fromfs
 *
 * Makes an Windows style security descriptor in absolute form
 * based on the given filesystem security information.
 *
 * Should call smb_sd_term() for the returned sd to free allocated
 * members.
 */
uint32_t
smb_sd_fromfs(smb_fssd_t *fs_sd, smb_sd_t *sd)
{
    uint32_t status = NT_STATUS_SUCCESS;
    smb_acl_t *acl = NULL;
    smb_sid_t *sid;
    idmap_stat idm_stat;

    assert(fs_sd);
    assert(sd);

    smb_sd_init(sd, SECURITY_DESCRIPTOR_REVISION);

    /* Owner */
    if (fs_sd->sd_secinfo & SMB_OWNER_SECINFO) {
        idm_stat = smb_idmap_getsid(fs_sd->sd_uid,
            SMB_IDMAP_USER, &sid);

        if (idm_stat != IDMAP_SUCCESS) {
            smb_sd_term(sd);
            return (NT_STATUS_NONE_MAPPED);
        }

        sd->sd_owner = sid;
    }

    /* Group */
    if (fs_sd->sd_secinfo & SMB_GROUP_SECINFO) {
        idm_stat = smb_idmap_getsid(fs_sd->sd_gid,
            SMB_IDMAP_GROUP, &sid);

        if (idm_stat != IDMAP_SUCCESS) {
            smb_sd_term(sd);
            return (NT_STATUS_NONE_MAPPED);
        }

        sd->sd_group = sid;
    }

    /* DACL */
    if (fs_sd->sd_secinfo & SMB_DACL_SECINFO) {
        if (fs_sd->sd_zdacl != NULL) {
            acl = smb_acl_from_zfs(fs_sd->sd_zdacl);
            if (acl == NULL) {
                smb_sd_term(sd);
                return (NT_STATUS_INTERNAL_ERROR);
            }

            /*
             * Need to sort the ACL before send it to Windows
             * clients. Winodws GUI is sensitive about the order
             * of ACEs.
             */
            smb_acl_sort(acl);
            smb_sd_set_dacl(sd, acl, B_TRUE,
                fs_sd->sd_zdacl->acl_flags);
        } else {
            smb_sd_set_dacl(sd, NULL, B_FALSE, 0);
        }
    }

    /* SACL */
    if (fs_sd->sd_secinfo & SMB_SACL_SECINFO) {
        if (fs_sd->sd_zsacl != NULL) {
            acl = smb_acl_from_zfs(fs_sd->sd_zsacl);
            if (acl == NULL) {
                smb_sd_term(sd);
                return (NT_STATUS_INTERNAL_ERROR);
            }

            smb_sd_set_sacl(sd, acl, B_TRUE,
                fs_sd->sd_zsacl->acl_flags);
        } else {
            smb_sd_set_sacl(sd, NULL, B_FALSE, 0);
        }
    }

    return (status);
}

static void
smb_sd_set_dacl(smb_sd_t *sd, smb_acl_t *acl, boolean_t present, int flags)
{
    assert((sd->sd_control & SE_SELF_RELATIVE) == 0);

    sd->sd_dacl = acl;

    if (flags & ACL_DEFAULTED)
        sd->sd_control |= SE_DACL_DEFAULTED;
    if (flags & ACL_AUTO_INHERIT)
        sd->sd_control |= SE_DACL_AUTO_INHERITED;
    if (flags & ACL_PROTECTED)
        sd->sd_control |= SE_DACL_PROTECTED;

    if (present)
        sd->sd_control |= SE_DACL_PRESENT;
}

static void
smb_sd_set_sacl(smb_sd_t *sd, smb_acl_t *acl, boolean_t present, int flags)
{
    assert((sd->sd_control & SE_SELF_RELATIVE) == 0);

    sd->sd_sacl = acl;

    if (flags & ACL_DEFAULTED)
        sd->sd_control |= SE_SACL_DEFAULTED;
    if (flags & ACL_AUTO_INHERIT)
        sd->sd_control |= SE_SACL_AUTO_INHERITED;
    if (flags & ACL_PROTECTED)
        sd->sd_control |= SE_SACL_PROTECTED;

    if (present)
        sd->sd_control |= SE_SACL_PRESENT;
}

/*
 * smb_fssd_init
 *
 * Initializes the given FS SD structure.
 */
void
smb_fssd_init(smb_fssd_t *fs_sd, uint32_t secinfo, uint32_t flags)
{
    bzero(fs_sd, sizeof (smb_fssd_t));
    fs_sd->sd_secinfo = secinfo;
    fs_sd->sd_flags = flags;
}

/*
 * smb_fssd_term
 *
 * Frees allocated memory for acl fields.
 */
void
smb_fssd_term(smb_fssd_t *fs_sd)
{
    assert(fs_sd);

    acl_free(fs_sd->sd_zdacl);
    acl_free(fs_sd->sd_zsacl);

    bzero(fs_sd, sizeof (smb_fssd_t));
}