// SPDX-License-Identifier: CDDL-1.0
/*
 * 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
 * https://opensource.org/license/CDDL-1.0.
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/avl.h>
#include <sys/misc.h>
#include <sys/kmem.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <acl/acl_common.h>
#include <sys/debug.h>

#define	ACE_POSIX_SUPPORTED_BITS (ACE_READ_DATA | \
    ACE_WRITE_DATA | ACE_APPEND_DATA | ACE_EXECUTE | \
    ACE_READ_ATTRIBUTES | ACE_READ_ACL | ACE_WRITE_ACL)


#define	ACL_SYNCHRONIZE_SET_DENY		0x0000001
#define	ACL_SYNCHRONIZE_SET_ALLOW		0x0000002
#define	ACL_SYNCHRONIZE_ERR_DENY		0x0000004
#define	ACL_SYNCHRONIZE_ERR_ALLOW		0x0000008

#define	ACL_WRITE_OWNER_SET_DENY		0x0000010
#define	ACL_WRITE_OWNER_SET_ALLOW		0x0000020
#define	ACL_WRITE_OWNER_ERR_DENY		0x0000040
#define	ACL_WRITE_OWNER_ERR_ALLOW		0x0000080

#define	ACL_DELETE_SET_DENY			0x0000100
#define	ACL_DELETE_SET_ALLOW			0x0000200
#define	ACL_DELETE_ERR_DENY			0x0000400
#define	ACL_DELETE_ERR_ALLOW			0x0000800

#define	ACL_WRITE_ATTRS_OWNER_SET_DENY		0x0001000
#define	ACL_WRITE_ATTRS_OWNER_SET_ALLOW		0x0002000
#define	ACL_WRITE_ATTRS_OWNER_ERR_DENY		0x0004000
#define	ACL_WRITE_ATTRS_OWNER_ERR_ALLOW		0x0008000

#define	ACL_WRITE_ATTRS_WRITER_SET_DENY		0x0010000
#define	ACL_WRITE_ATTRS_WRITER_SET_ALLOW	0x0020000
#define	ACL_WRITE_ATTRS_WRITER_ERR_DENY		0x0040000
#define	ACL_WRITE_ATTRS_WRITER_ERR_ALLOW	0x0080000

#define	ACL_WRITE_NAMED_WRITER_SET_DENY		0x0100000
#define	ACL_WRITE_NAMED_WRITER_SET_ALLOW	0x0200000
#define	ACL_WRITE_NAMED_WRITER_ERR_DENY		0x0400000
#define	ACL_WRITE_NAMED_WRITER_ERR_ALLOW	0x0800000

#define	ACL_READ_NAMED_READER_SET_DENY		0x1000000
#define	ACL_READ_NAMED_READER_SET_ALLOW		0x2000000
#define	ACL_READ_NAMED_READER_ERR_DENY		0x4000000
#define	ACL_READ_NAMED_READER_ERR_ALLOW		0x8000000


#define	ACE_VALID_MASK_BITS (\
    ACE_READ_DATA | \
    ACE_LIST_DIRECTORY | \
    ACE_WRITE_DATA | \
    ACE_ADD_FILE | \
    ACE_APPEND_DATA | \
    ACE_ADD_SUBDIRECTORY | \
    ACE_READ_NAMED_ATTRS | \
    ACE_WRITE_NAMED_ATTRS | \
    ACE_EXECUTE | \
    ACE_DELETE_CHILD | \
    ACE_READ_ATTRIBUTES | \
    ACE_WRITE_ATTRIBUTES | \
    ACE_DELETE | \
    ACE_READ_ACL | \
    ACE_WRITE_ACL | \
    ACE_WRITE_OWNER | \
    ACE_SYNCHRONIZE)

#define	ACE_MASK_UNDEFINED			0x80000000

#define	ACE_VALID_FLAG_BITS (ACE_FILE_INHERIT_ACE | \
    ACE_DIRECTORY_INHERIT_ACE | \
    ACE_NO_PROPAGATE_INHERIT_ACE | ACE_INHERIT_ONLY_ACE | \
    ACE_SUCCESSFUL_ACCESS_ACE_FLAG | ACE_FAILED_ACCESS_ACE_FLAG | \
    ACE_IDENTIFIER_GROUP | ACE_OWNER | ACE_GROUP | ACE_EVERYONE)

/*
 * ACL conversion helpers
 */

typedef enum {
	ace_unused,
	ace_user_obj,
	ace_user,
	ace_group, /* includes GROUP and GROUP_OBJ */
	ace_other_obj
} ace_to_aent_state_t;

typedef struct acevals {
	uid_t key;
	avl_node_t avl;
	uint32_t mask;
	uint32_t allowed;
	uint32_t denied;
	int aent_type;
} acevals_t;

typedef struct ace_list {
	acevals_t user_obj;
	avl_tree_t user;
	int numusers;
	acevals_t group_obj;
	avl_tree_t group;
	int numgroups;
	acevals_t other_obj;
	uint32_t acl_mask;
	int hasmask;
	int dfacl_flag;
	ace_to_aent_state_t state;
	int seen; /* bitmask of all aclent_t a_type values seen */
} ace_list_t;

/*
 * Generic shellsort, from K&R (1st ed, p 58.), somewhat modified.
 * v = Ptr to array/vector of objs
 * n = # objs in the array
 * s = size of each obj (must be multiples of a word size)
 * f = ptr to function to compare two objs
 *	returns (-1 = less than, 0 = equal, 1 = greater than
 */
void
ksort(caddr_t v, int n, int s, int (*f)(void *, void *))
{
	int g, i, j, ii;
	unsigned int *p1, *p2;
	unsigned int tmp;

	/* No work to do */
	if (v == NULL || n <= 1)
		return;

	/* Sanity check on arguments */
	ASSERT3U(((uintptr_t)v & 0x3), ==, 0);
	ASSERT3S((s & 0x3), ==, 0);
	ASSERT3S(s, >, 0);
	for (g = n / 2; g > 0; g /= 2) {
		for (i = g; i < n; i++) {
			for (j = i - g; j >= 0 &&
			    (*f)(v + j * s, v + (j + g) * s) == 1;
			    j -= g) {
				p1 = (void *)(v + j * s);
				p2 = (void *)(v + (j + g) * s);
				for (ii = 0; ii < s / 4; ii++) {
					tmp = *p1;
					*p1++ = *p2;
					*p2++ = tmp;
				}
			}
		}
	}
}

/*
 * Compare two acls, all fields.  Returns:
 * -1 (less than)
 *  0 (equal)
 * +1 (greater than)
 */
int
cmp2acls(void *a, void *b)
{
	aclent_t *x = (aclent_t *)a;
	aclent_t *y = (aclent_t *)b;

	/* Compare types */
	if (x->a_type < y->a_type)
		return (-1);
	if (x->a_type > y->a_type)
		return (1);
	/* Equal types; compare id's */
	if (x->a_id < y->a_id)
		return (-1);
	if (x->a_id > y->a_id)
		return (1);
	/* Equal ids; compare perms */
	if (x->a_perm < y->a_perm)
		return (-1);
	if (x->a_perm > y->a_perm)
		return (1);
	/* Totally equal */
	return (0);
}

static int
cacl_malloc(void **ptr, size_t size)
{
	*ptr = kmem_zalloc(size, KM_SLEEP);
	return (0);
}


#define	SET_ACE(acl, index, who, mask, type, flags) { \
	acl[0][index].a_who = (uint32_t)who; \
	acl[0][index].a_type = type; \
	acl[0][index].a_flags = flags; \
	acl[0][index++].a_access_mask = mask; \
}

void
acl_trivial_access_masks(mode_t mode, boolean_t isdir, trivial_acl_t *masks)
{
	uint32_t read_mask = ACE_READ_DATA;
	uint32_t write_mask = ACE_WRITE_DATA|ACE_APPEND_DATA;
	uint32_t execute_mask = ACE_EXECUTE;

	(void) isdir;	/* will need this later */

	masks->deny1 = 0;
	if (!(mode & S_IRUSR) && (mode & (S_IRGRP|S_IROTH)))
		masks->deny1 |= read_mask;
	if (!(mode & S_IWUSR) && (mode & (S_IWGRP|S_IWOTH)))
		masks->deny1 |= write_mask;
	if (!(mode & S_IXUSR) && (mode & (S_IXGRP|S_IXOTH)))
		masks->deny1 |= execute_mask;

	masks->deny2 = 0;
	if (!(mode & S_IRGRP) && (mode & S_IROTH))
		masks->deny2 |= read_mask;
	if (!(mode & S_IWGRP) && (mode & S_IWOTH))
		masks->deny2 |= write_mask;
	if (!(mode & S_IXGRP) && (mode & S_IXOTH))
		masks->deny2 |= execute_mask;

	masks->allow0 = 0;
	if ((mode & S_IRUSR) && (!(mode & S_IRGRP) && (mode & S_IROTH)))
		masks->allow0 |= read_mask;
	if ((mode & S_IWUSR) && (!(mode & S_IWGRP) && (mode & S_IWOTH)))
		masks->allow0 |= write_mask;
	if ((mode & S_IXUSR) && (!(mode & S_IXGRP) && (mode & S_IXOTH)))
		masks->allow0 |= execute_mask;

	masks->owner = ACE_WRITE_ATTRIBUTES|ACE_WRITE_OWNER|ACE_WRITE_ACL|
	    ACE_WRITE_NAMED_ATTRS|ACE_READ_ACL|ACE_READ_ATTRIBUTES|
	    ACE_READ_NAMED_ATTRS|ACE_SYNCHRONIZE;
	if (mode & S_IRUSR)
		masks->owner |= read_mask;
	if (mode & S_IWUSR)
		masks->owner |= write_mask;
	if (mode & S_IXUSR)
		masks->owner |= execute_mask;

	masks->group = ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_NAMED_ATTRS|
	    ACE_SYNCHRONIZE;
	if (mode & S_IRGRP)
		masks->group |= read_mask;
	if (mode & S_IWGRP)
		masks->group |= write_mask;
	if (mode & S_IXGRP)
		masks->group |= execute_mask;

	masks->everyone = ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_NAMED_ATTRS|
	    ACE_SYNCHRONIZE;
	if (mode & S_IROTH)
		masks->everyone |= read_mask;
	if (mode & S_IWOTH)
		masks->everyone |= write_mask;
	if (mode & S_IXOTH)
		masks->everyone |= execute_mask;
}

int
acl_trivial_create(mode_t mode, boolean_t isdir, ace_t **acl, int *count)
{
	int		index = 0;
	int		error;
	trivial_acl_t	masks;

	*count = 3;
	acl_trivial_access_masks(mode, isdir, &masks);

	if (masks.allow0)
		(*count)++;
	if (masks.deny1)
		(*count)++;
	if (masks.deny2)
		(*count)++;

	if ((error = cacl_malloc((void **)acl, *count * sizeof (ace_t))) != 0)
		return (error);

	if (masks.allow0) {
		SET_ACE(acl, index, -1, masks.allow0,
		    ACE_ACCESS_ALLOWED_ACE_TYPE, ACE_OWNER);
	}
	if (masks.deny1) {
		SET_ACE(acl, index, -1, masks.deny1,
		    ACE_ACCESS_DENIED_ACE_TYPE, ACE_OWNER);
	}
	if (masks.deny2) {
		SET_ACE(acl, index, -1, masks.deny2,
		    ACE_ACCESS_DENIED_ACE_TYPE, ACE_GROUP|ACE_IDENTIFIER_GROUP);
	}

	SET_ACE(acl, index, -1, masks.owner, ACE_ACCESS_ALLOWED_ACE_TYPE,
	    ACE_OWNER);
	SET_ACE(acl, index, -1, masks.group, ACE_ACCESS_ALLOWED_ACE_TYPE,
	    ACE_IDENTIFIER_GROUP|ACE_GROUP);
	SET_ACE(acl, index, -1, masks.everyone, ACE_ACCESS_ALLOWED_ACE_TYPE,
	    ACE_EVERYONE);

	return (0);
}

/*
 * ace_trivial:
 * determine whether an ace_t acl is trivial
 *
 * Trivialness implies that the acl is composed of only
 * owner, group, everyone entries.  ACL can't
 * have read_acl denied, and write_owner/write_acl/write_attributes
 * can only be owner@ entry.
 */
int
ace_trivial_common(void *acep, int aclcnt,
    uintptr_t (*walk)(void *, uintptr_t, int aclcnt,
    uint16_t *, uint16_t *, uint32_t *))
{
	uint16_t flags;
	uint32_t mask;
	uint16_t type;
	uintptr_t cookie = 0;

	while ((cookie = walk(acep, cookie, aclcnt, &flags, &type, &mask))) {
		switch (flags & ACE_TYPE_FLAGS) {
		case ACE_OWNER:
		case ACE_GROUP|ACE_IDENTIFIER_GROUP:
		case ACE_EVERYONE:
			break;
		default:
			return (1);

		}

		if (flags & (ACE_FILE_INHERIT_ACE|
		    ACE_DIRECTORY_INHERIT_ACE|ACE_NO_PROPAGATE_INHERIT_ACE|
		    ACE_INHERIT_ONLY_ACE))
			return (1);

		/*
		 * Special check for some special bits
		 *
		 * Don't allow anybody to deny reading basic
		 * attributes or a files ACL.
		 */
		if ((mask & (ACE_READ_ACL|ACE_READ_ATTRIBUTES)) &&
		    (type == ACE_ACCESS_DENIED_ACE_TYPE))
			return (1);

		/*
		 * Delete permissions are never set by default
		 */
		if (mask & (ACE_DELETE|ACE_DELETE_CHILD))
			return (1);
		/*
		 * only allow owner@ to have
		 * write_acl/write_owner/write_attributes/write_xattr/
		 */
		if (type == ACE_ACCESS_ALLOWED_ACE_TYPE &&
		    (!(flags & ACE_OWNER) && (mask &
		    (ACE_WRITE_OWNER|ACE_WRITE_ACL| ACE_WRITE_ATTRIBUTES|
		    ACE_WRITE_NAMED_ATTRS))))
			return (1);

	}
	return (0);
}