/*
 * 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 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright 2021 Tintri by DDN, Inc. All rights reserved.
 */

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

#include <smbsrv/smb_kproto.h>
#include <smbsrv/smb_fsops.h>
#include <smbsrv/smb_idmap.h>

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);
static uint32_t smb_sd_fromfs(smb_fssd_t *, smb_sd_t *);

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.
 *
 * Note: This is used for 'create-with-sd'. 'set-security-info' provides the
 * secinfo as part of the request, but create does not, so we must infer it.
 */
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_control & SE_DACL_PRESENT) != 0)
                sec_info |= SMB_DACL_SECINFO;

        if ((sd->sd_control & SE_SACL_PRESENT) != 0)
                sec_info |= SMB_SACL_SECINFO;

        return (sec_info);
}

/*
 * smb_sd_read
 *
 * Read uid, gid and ACL from filesystem. The returned ACL from read
 * routine is always in ZFS format. Convert the ZFS acl to a Win acl
 * 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(smb_request_t *sr, smb_sd_t *sd, uint32_t secinfo)
{
        smb_fssd_t fs_sd;
        smb_node_t *node;
        uint32_t status = NT_STATUS_SUCCESS;
        uint32_t sd_flags;
        int error;

        node = sr->fid_ofile->f_node;
        sd_flags = smb_node_is_dir(node) ? SMB_FSSD_FLAGS_DIR : 0;
        smb_fssd_init(&fs_sd, secinfo, sd_flags);

        error = smb_fsop_sdread(sr, sr->user_cr, node, &fs_sd);
        if (error)
                return (smb_errno2status(error));

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

        return (status);
}

/*
 * smb_sd_write
 *
 * Takes a Win SD in absolute form, converts it to
 * ZFS format and write it to filesystem. The write routine
 * converts ZFS acl to Posix acl if required.
 */
uint32_t
smb_sd_write(smb_request_t *sr, smb_sd_t *sd, uint32_t secinfo)
{
        smb_node_t *node;
        smb_fssd_t fs_sd;
        uint32_t status;
        uint32_t sd_flags;
        int error;

        node = sr->fid_ofile->f_node;
        sd_flags = smb_node_is_dir(node) ? SMB_FSSD_FLAGS_DIR : 0;
        smb_fssd_init(&fs_sd, secinfo, sd_flags);

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

        error = smb_fsop_sdwrite(sr, sr->user_cr, node, &fs_sd, 0);
        smb_fssd_term(&fs_sd);

        if (error) {
                if (error == EBADE)
                        return (NT_STATUS_INVALID_OWNER);
                return (smb_errno2status(error));
        }

        return (NT_STATUS_SUCCESS);
}


/*
 * 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);
                }
        }

        /*
         * In SMB, the 'secinfo' determines which parts of the SD the client
         * intends to change. Notably, this includes changing the DACL_PRESENT
         * and SACL_PRESENT control bits. The client can specify e.g.
         * SACL_SECINFO, but not SACL_PRESENT, and this means the client intends
         * to remove the SACL.
         *
         * Note that Windows behavior differs from that described in [MS-DTYP].
         * MS-DTYP states that the offset is nonzero if-and-only-if the PRESENT
         * bit is set. It also states that a DACL that is marked non-present
         * is equivalent to 'no security', but one that is marked present and
         * provides no ACEs is equivalent to 'no access'.
         *
         * Windows, on the other hand, allows the offset to be 0 even when
         * the PRESENT bit is set, and only provides security when the DACL
         * offset is non-zero. It will also convert an SD where the DACL is
         * marked not-present to one where the PRESENT bit is set and the
         * offset is 0.
         *
         * If the *_PRESENT bit isn't set, then the respective ACL will be NULL.
         * For the fssd, we allow the SACL to be NULL, but we MUST have a DACL.
         * If the DACL is NULL, that's equivalent to "everyone:full_set:allow".
         *
         * The IMPLY's should be enforced by smb_decode_sd().
         */

        /* DACL */
        if (fs_sd->sd_secinfo & SMB_DACL_SECINFO) {
                IMPLY(sd->sd_dacl != NULL,
                    (sd->sd_control & SE_DACL_PRESENT) != 0);
                status = smb_acl_to_zfs(sd->sd_dacl, flags,
                    SMB_DACL_SECINFO, &fs_sd->sd_zdacl);
                if (status != NT_STATUS_SUCCESS)
                        return (status);
        }

        /* SACL */
        if (fs_sd->sd_secinfo & SMB_SACL_SECINFO) {
                IMPLY(sd->sd_sacl != NULL,
                    (sd->sd_control & SE_SACL_PRESENT) != 0);
                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);
                        }
                }
        }

        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.
 */
static 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);

        smb_fsacl_free(fs_sd->sd_zdacl);
        smb_fsacl_free(fs_sd->sd_zsacl);
        bzero(fs_sd, sizeof (smb_fssd_t));
}