path: root/source3/modules/vfs_acl_common.c

/*
 * Store Windows ACLs in data store - common functions.
 * #included into modules/vfs_acl_xattr.c and modules/vfs_acl_tdb.c
 *
 * Copyright (C) Volker Lendecke, 2008
 * Copyright (C) Jeremy Allison, 2009
 * Copyright (C) Ralph Böhme, 2016
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "smbd/smbd.h"
#include "system/filesys.h"
#include "../libcli/security/security.h"
#include "../librpc/gen_ndr/ndr_security.h"
#include "../lib/util/bitmap.h"
#include "passdb/lookup_sid.h"

static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
			DATA_BLOB *pblob,
			uint16_t hash_type,
			uint8_t hash[XATTR_SD_HASH_SIZE]);

static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
			vfs_handle_struct *handle,
			files_struct *fsp,
			const struct smb_filename *smb_fname,
			DATA_BLOB *pblob);

static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
			files_struct *fsp,
			DATA_BLOB *pblob);

#define HASH_SECURITY_INFO (SECINFO_OWNER | \
				SECINFO_GROUP | \
				SECINFO_DACL | \
				SECINFO_SACL)

enum default_acl_style {DEFAULT_ACL_POSIX, DEFAULT_ACL_WINDOWS};

static const struct enum_list default_acl_style[] = {
	{DEFAULT_ACL_POSIX,	"posix"},
	{DEFAULT_ACL_WINDOWS,	"windows"}
};

struct acl_common_config {
	bool ignore_system_acls;
	enum default_acl_style default_acl_style;
};

static bool init_acl_common_config(vfs_handle_struct *handle)
{
	struct acl_common_config *config = NULL;

	config = talloc_zero(handle->conn, struct acl_common_config);
	if (config == NULL) {
		DBG_ERR("talloc_zero() failed\n");
		errno = ENOMEM;
		return false;
	}

	config->ignore_system_acls = lp_parm_bool(SNUM(handle->conn),
						  ACL_MODULE_NAME,
						  "ignore system acls",
						  false);
	config->default_acl_style = lp_parm_enum(SNUM(handle->conn),
						 ACL_MODULE_NAME,
						 "default acl style",
						 default_acl_style,
						 DEFAULT_ACL_POSIX);

	SMB_VFS_HANDLE_SET_DATA(handle, config, NULL,
				struct acl_common_config,
				return false);

	return true;
}


/*******************************************************************
 Hash a security descriptor.
*******************************************************************/

static NTSTATUS hash_blob_sha256(DATA_BLOB blob,
				 uint8_t *hash)
{
	SHA256_CTX tctx;

	memset(hash, '\0', XATTR_SD_HASH_SIZE);

	samba_SHA256_Init(&tctx);
	samba_SHA256_Update(&tctx, blob.data, blob.length);
	samba_SHA256_Final(hash, &tctx);

	return NT_STATUS_OK;
}

/*******************************************************************
 Hash a security descriptor.
*******************************************************************/

static NTSTATUS hash_sd_sha256(struct security_descriptor *psd,
			uint8_t *hash)
{
	DATA_BLOB blob;
	NTSTATUS status;

	memset(hash, '\0', XATTR_SD_HASH_SIZE);
	status = create_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash);
	if (!NT_STATUS_IS_OK(status)) {
		return status;
	}
	return hash_blob_sha256(blob, hash);
}

/*******************************************************************
 Parse out a struct security_descriptor from a DATA_BLOB.
*******************************************************************/

static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
			       TALLOC_CTX *mem_ctx,
			       struct security_descriptor **ppdesc,
			       uint16_t *p_hash_type,
			       uint16_t *p_version,
			       uint8_t hash[XATTR_SD_HASH_SIZE],
			       uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE])
{
	struct xattr_NTACL xacl;
	enum ndr_err_code ndr_err;
	size_t sd_size;
	TALLOC_CTX *frame = talloc_stackframe();

	ndr_err = ndr_pull_struct_blob(pblob, frame, &xacl,
			(ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);

	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		DBG_INFO("ndr_pull_xattr_NTACL failed: %s\n",
			 ndr_errstr(ndr_err));
		TALLOC_FREE(frame);
		return ndr_map_error2ntstatus(ndr_err);
	}

	*p_version = xacl.version;

	switch (xacl.version) {
		case 1:
			*ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
					xacl.info.sd->type | SEC_DESC_SELF_RELATIVE,
					xacl.info.sd->owner_sid,
					xacl.info.sd->group_sid,
					xacl.info.sd->sacl,
					xacl.info.sd->dacl,
					&sd_size);
			/* No hash - null out. */
			*p_hash_type = XATTR_SD_HASH_TYPE_NONE;
			memset(hash, '\0', XATTR_SD_HASH_SIZE);
			break;
		case 2:
			*ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
					xacl.info.sd_hs2->sd->type | SEC_DESC_SELF_RELATIVE,
					xacl.info.sd_hs2->sd->owner_sid,
					xacl.info.sd_hs2->sd->group_sid,
					xacl.info.sd_hs2->sd->sacl,
					xacl.info.sd_hs2->sd->dacl,
					&sd_size);
			/* No hash - null out. */
			*p_hash_type = XATTR_SD_HASH_TYPE_NONE;
			memset(hash, '\0', XATTR_SD_HASH_SIZE);
			break;
		case 3:
			*ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
					xacl.info.sd_hs3->sd->type | SEC_DESC_SELF_RELATIVE,
					xacl.info.sd_hs3->sd->owner_sid,
					xacl.info.sd_hs3->sd->group_sid,
					xacl.info.sd_hs3->sd->sacl,
					xacl.info.sd_hs3->sd->dacl,
					&sd_size);
			*p_hash_type = xacl.info.sd_hs3->hash_type;
			/* Current version 3 (if no sys acl hash available). */
			memcpy(hash, xacl.info.sd_hs3->hash, XATTR_SD_HASH_SIZE);
			break;
		case 4:
			*ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
					xacl.info.sd_hs4->sd->type | SEC_DESC_SELF_RELATIVE,
					xacl.info.sd_hs4->sd->owner_sid,
					xacl.info.sd_hs4->sd->group_sid,
					xacl.info.sd_hs4->sd->sacl,
					xacl.info.sd_hs4->sd->dacl,
					&sd_size);
			*p_hash_type = xacl.info.sd_hs4->hash_type;
			/* Current version 4. */
			memcpy(hash, xacl.info.sd_hs4->hash, XATTR_SD_HASH_SIZE);
			memcpy(sys_acl_hash, xacl.info.sd_hs4->sys_acl_hash, XATTR_SD_HASH_SIZE);
			break;
		default:
			TALLOC_FREE(frame);
			return NT_STATUS_REVISION_MISMATCH;
	}

	TALLOC_FREE(frame);

	return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
}

/*******************************************************************
 Create a DATA_BLOB from a hash of the security descriptor storead at
 the system layer and the NT ACL we wish to preserve
*******************************************************************/

static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
			DATA_BLOB *pblob,
			uint16_t hash_type,
			uint8_t hash[XATTR_SD_HASH_SIZE])
{
	struct xattr_NTACL xacl;
	struct security_descriptor_hash_v3 sd_hs3;
	enum ndr_err_code ndr_err;
	TALLOC_CTX *ctx = talloc_tos();

	ZERO_STRUCT(xacl);
	ZERO_STRUCT(sd_hs3);

	xacl.version = 3;
	xacl.info.sd_hs3 = &sd_hs3;
	xacl.info.sd_hs3->sd = discard_const_p(struct security_descriptor, psd);
	xacl.info.sd_hs3->hash_type = hash_type;
	memcpy(&xacl.info.sd_hs3->hash[0], hash, XATTR_SD_HASH_SIZE);

	ndr_err = ndr_push_struct_blob(
			pblob, ctx, &xacl,
			(ndr_push_flags_fn_t)ndr_push_xattr_NTACL);

	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		DBG_INFO("ndr_push_xattr_NTACL failed: %s\n",
			 ndr_errstr(ndr_err));
		return ndr_map_error2ntstatus(ndr_err);
	}

	return NT_STATUS_OK;
}

/*******************************************************************
 Create a DATA_BLOB from a hash of the security descriptors 
 (system and NT) stored at the system layer and the NT ACL we wish 
 to preserve.
*******************************************************************/

static NTSTATUS create_sys_acl_blob(const struct security_descriptor *psd,
				    DATA_BLOB *pblob,
				    uint16_t hash_type,
				    uint8_t hash[XATTR_SD