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      1 /*-
      2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
      3  *
      4  * Copyright (c) 2001-2002 Chris D. Faulhaber
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 #if 0
     31 __FBSDID("$FreeBSD: head/lib/libc/posix1e/acl_delete_entry.c 326193 2017-11-25 17:12:48Z pfg $");
     32 #else
     33 __RCSID("$NetBSD: acl_delete_entry.c,v 1.1 2020/05/16 18:31:47 christos Exp $");
     34 #endif
     35 
     36 #include "namespace.h"
     37 #include <sys/types.h>
     38 #include <sys/acl.h>
     39 #include <errno.h>
     40 #include <string.h>
     41 #include <stdio.h>
     42 
     43 #include "acl_support.h"
     44 
     45 static int
     46 _entry_matches(const acl_entry_t a, const acl_entry_t b)
     47 {
     48 	/*
     49 	 * There is a semantical difference here between NFSv4 and POSIX
     50 	 * draft ACLs.  In POSIX, there may be only one entry for the particular
     51 	 * user or group.  In NFSv4 ACL, there may be any number of them.  We're
     52 	 * trying to be more specific here in that case.
     53 	 */
     54 	switch (_entry_brand(a)) {
     55 	case ACL_BRAND_NFS4:
     56 		if (a->ae_tag != b->ae_tag || a->ae_entry_type != b->ae_entry_type)
     57 			return (0);
     58 
     59 		/* If ae_ids matter, compare them as well. */
     60 		if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
     61 			if (a->ae_id != b->ae_id)
     62 				return (0);
     63 		}
     64 
     65 		return (1);
     66 
     67 	default:
     68 		if ((a->ae_tag == b->ae_tag) && (a->ae_id == b->ae_id))
     69 			return (1);
     70 	}
     71 
     72 	return (0);
     73 }
     74 
     75 /*
     76  * acl_delete_entry() (23.4.9): remove the ACL entry indicated by entry_d
     77  * from acl.
     78  */
     79 int
     80 acl_delete_entry(acl_t acl, acl_entry_t entry_d)
     81 {
     82 	struct acl_entry entry_int;
     83 	size_t i, j;
     84 	int found = 0;
     85 
     86 	if (acl == NULL || entry_d == NULL) {
     87 		errno = EINVAL;
     88 		return (-1);
     89 	}
     90 
     91 	if (_entry_brand(entry_d) != _acl_brand(acl)) {
     92 		errno = EINVAL;
     93 		return (-1);
     94 	}
     95 
     96 	if ((acl->ats_acl.acl_cnt < 1) ||
     97 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
     98 		errno = EINVAL;
     99 		return (-1);
    100 	}
    101 
    102 	/* Use a local copy to prevent deletion of more than this entry */
    103 	entry_int = *entry_d;
    104 
    105 	for (i = 0; i < acl->ats_acl.acl_cnt;) {
    106 		if (_entry_matches(&(acl->ats_acl.acl_entry[i]), &entry_int)) {
    107 			/* ...shift the remaining entries... */
    108 			for (j = i; j < acl->ats_acl.acl_cnt - 1; ++j)
    109 				acl->ats_acl.acl_entry[j] =
    110 				    acl->ats_acl.acl_entry[j+1];
    111 			/* ...drop the count and zero the unused entry... */
    112 			acl->ats_acl.acl_cnt--;
    113 			bzero(&acl->ats_acl.acl_entry[j],
    114 			    sizeof(struct acl_entry));
    115 			acl->ats_cur_entry = 0;
    116 
    117 			/* Continue with the loop to remove all matching entries. */
    118 			found = 1;
    119 		} else
    120 			i++;
    121 	}
    122 
    123 	if (found)
    124 		return (0);
    125 
    126 	errno = EINVAL;
    127 	return (-1);
    128 }
    129 
    130 int
    131 acl_delete_entry_np(acl_t acl, int offset)
    132 {
    133 	struct acl *acl_int;
    134 	size_t i;
    135 
    136 	if (acl == NULL) {
    137 		errno = EINVAL;
    138 		return (-1);
    139 	}
    140 
    141 	acl_int = &acl->ats_acl;
    142 
    143 	if (offset < 0 || (size_t)offset >= acl_int->acl_cnt) {
    144 		errno = EINVAL;
    145 		return (-1);
    146 	}
    147 
    148 	if ((acl->ats_acl.acl_cnt < 1) ||
    149 	    (acl->ats_acl.acl_cnt > ACL_MAX_ENTRIES)) {
    150 		errno = EINVAL;
    151 		return (-1);
    152 	}
    153 
    154 	/* ...shift the remaining entries... */
    155 	for (i = offset; i < acl->ats_acl.acl_cnt - 1; ++i)
    156 		acl->ats_acl.acl_entry[i] =
    157 		    acl->ats_acl.acl_entry[i+1];
    158 	/* ...drop the count and zero the unused entry... */
    159 	acl->ats_acl.acl_cnt--;
    160 	bzero(&acl->ats_acl.acl_entry[i],
    161 	    sizeof(struct acl_entry));
    162 	acl->ats_cur_entry = 0;
    163 
    164 	return (0);
    165 }
    166