2 * Copyright (c) 1999 Robert N. M. Watson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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9 * notice, this list of conditions and the following disclaimer.
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26 * $FreeBSD: src/lib/libposix1e/acl_support.c,v 1.3 2000/01/26 04:19:37 rwatson Exp $
29 * Support functionality for the POSIX.1e ACL interface
30 * These calls are intended only to be called within the library.
33 #include <sys/types.h>
41 #include "acl_support.h"
43 #define ACL_STRING_PERM_WRITE 'w'
44 #define ACL_STRING_PERM_READ 'r'
45 #define ACL_STRING_PERM_EXEC 'x'
46 #define ACL_STRING_PERM_NONE '-'
49 * acl_entry_compare -- compare two acl_entry structures to determine the
50 * order they should appear in. Used by acl_sort to sort ACL entries into
51 * the kernel-desired order -- i.e., the order useful for evaluation and
52 * O(n) validity checking. Beter to have an O(nlogn) sort in userland and
53 * an O(n) in kernel than to have both in kernel.
55 typedef int (*compare)(const void *, const void *);
57 acl_entry_compare(struct acl_entry *a, struct acl_entry *b)
60 * First, sort between tags -- conveniently defined in the correct
61 * order for verification.
63 if (a->ae_tag < b->ae_tag)
65 if (a->ae_tag > b->ae_tag)
69 * Next compare uids/gids on appropriate types.
72 if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) {
73 if (a->ae_id < b->ae_id)
75 if (a->ae_id > b->ae_id)
78 /* shouldn't be equal, fall through to the invalid case */
82 * Don't know how to sort multiple entries of the rest--either it's
83 * a bad entry, or there shouldn't be more than one. Ignore and the
84 * validity checker can get it later.
90 * acl_sort -- sort ACL entries.
91 * Give the opportunity to fail, althouh we don't currently have a way
98 qsort(&acl->acl_entry[0], acl->acl_cnt, sizeof(struct acl_entry),
99 (compare) acl_entry_compare);
105 * acl_posix1e -- in what situations should we acl_sort before submission?
106 * We apply posix1e ACL semantics for any ACL of type ACL_TYPE_ACCESS or
110 acl_posix1e(acl_t acl, acl_type_t type)
113 return ((type == ACL_TYPE_ACCESS) || (type == ACL_TYPE_DEFAULT));
117 * acl_check -- given an ACL, check its validity. This is mirrored from
118 * code in sys/kern/kern_acl.c, and if changes are made in one, they should
119 * be made in the other also. This copy of acl_check is made available
120 * in userland for the benefit of processes wanting to check ACLs for
121 * validity before submitting them to the kernel, or for performing
122 * in userland file system checking. Needless to say, the kernel makes
123 * the real checks on calls to get/setacl.
125 * See the comments in kernel for explanation -- just briefly, it assumes
126 * an already sorted ACL, and checks based on that assumption. The
127 * POSIX.1e interface, acl_valid(), will perform the sort before calling
128 * this. Returns 0 on success, EINVAL on failure.
131 acl_check(struct acl *acl)
133 struct acl_entry *entry; /* current entry */
134 uid_t obj_uid=-1, obj_gid=-1, highest_uid=0, highest_gid=0;
135 int stage = ACL_USER_OBJ;
137 int count_user_obj=0, count_user=0, count_group_obj=0,
138 count_group=0, count_mask=0, count_other=0;
140 /* printf("acl_check: checking acl with %d entries\n", acl->acl_cnt); */
141 while (i < acl->acl_cnt) {
143 entry = &acl->acl_entry[i];
145 if ((entry->ae_perm | ACL_PERM_BITS) != ACL_PERM_BITS)
148 switch(entry->ae_tag) {
150 /* printf("acl_check: %d: ACL_USER_OBJ\n", i); */
151 if (stage > ACL_USER_OBJ)
155 obj_uid = entry->ae_id;
159 /* printf("acl_check: %d: ACL_USER\n", i); */
160 if (stage > ACL_USER)
163 if (entry->ae_id == obj_uid)
165 if (count_user && (entry->ae_id <= highest_uid))
167 highest_uid = entry->ae_id;
172 /* printf("acl_check: %d: ACL_GROUP_OBJ\n", i); */
173 if (stage > ACL_GROUP_OBJ)
177 obj_gid = entry->ae_id;
181 /* printf("acl_check: %d: ACL_GROUP\n", i); */
182 if (stage > ACL_GROUP)
185 if (entry->ae_id == obj_gid)
187 if (count_group && (entry->ae_id <= highest_gid))
189 highest_gid = entry->ae_id;
194 /* printf("acl_check: %d: ACL_MASK\n", i); */
195 if (stage > ACL_MASK)
202 /* printf("acl_check: %d: ACL_OTHER\n", i); */
203 if (stage > ACL_OTHER)
210 /* printf("acl_check: %d: INVALID\n", i); */
216 if (count_user_obj != 1)
219 if (count_group_obj != 1)
222 if (count_mask != 0 && count_mask != 1)
225 if (count_other != 1)
233 * Given a uid/gid, return a username/groupname for the text form of an ACL
234 * XXX NOT THREAD SAFE, RELIES ON GETPWUID, GETGRGID
235 * XXX USES *PW* AND *GR* WHICH ARE STATEFUL AND THEREFORE THIS ROUTINE
236 * MAY HAVE SIDE-EFFECTS
239 acl_id_to_name(acl_tag_t tag, uid_t id, ssize_t buf_len, char *buf)
249 i = snprintf(buf, buf_len, "%d", id);
251 i = snprintf(buf, buf_len, "%s", p->pw_name);
262 i = snprintf(buf, buf_len, "%d", id);
264 i = snprintf(buf, buf_len, "%s", g->gr_name);
279 * Given a username/groupname from a text form of an ACL, return the uid/gid
280 * XXX NOT THREAD SAFE, RELIES ON GETPWNAM, GETGRNAM
281 * XXX USES *PW* AND *GR* WHICH ARE STATEFUL AND THEREFORE THIS ROUTINE
282 * MAY HAVE SIDE-EFFECTS
284 * XXX currently doesn't deal correctly with a numeric uid being passed
285 * instead of a username. What is correct behavior here? Check chown.
288 acl_name_to_id(acl_tag_t tag, char *name, uid_t *id)
319 * Given a right-shifted permission (i.e., direct ACL_PERM_* mask), fill
320 * in a string describing the permissions.
323 acl_perm_to_string(acl_perm_t perm, ssize_t buf_len, char *buf)
326 if (buf_len < ACL_STRING_PERM_MAXSIZE + 1) {
331 if ((perm | ACL_PERM_BITS) != ACL_PERM_BITS) {
336 buf[3] = 0; /* null terminate */
338 if (perm & ACL_PERM_READ)
339 buf[0] = ACL_STRING_PERM_READ;
341 buf[0] = ACL_STRING_PERM_NONE;
343 if (perm & ACL_PERM_WRITE)
344 buf[1] = ACL_STRING_PERM_WRITE;
346 buf[1] = ACL_STRING_PERM_NONE;
348 if (perm & ACL_PERM_EXEC)
349 buf[2] = ACL_STRING_PERM_EXEC;
351 buf[2] = ACL_STRING_PERM_NONE;
357 * given a string, return a permission describing it
360 acl_string_to_perm(char *string, acl_perm_t *perm)
362 acl_perm_t myperm = ACL_PERM_NONE;
368 case ACL_STRING_PERM_READ:
369 myperm |= ACL_PERM_READ;
371 case ACL_STRING_PERM_WRITE:
372 myperm |= ACL_PERM_WRITE;
374 case ACL_STRING_PERM_EXEC:
375 myperm |= ACL_PERM_EXEC;
377 case ACL_STRING_PERM_NONE:
390 * Add an ACL entry without doing much checking, et al
393 acl_add_entry(acl_t acl, acl_tag_t tag, uid_t id, acl_perm_t perm)
397 if (acl->acl_cnt >= ACL_MAX_ENTRIES) {
402 e = &(acl->acl_entry[acl->acl_cnt]);