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Diffstat (limited to 'lib/libc/posix1e/acl_support.c')
| -rw-r--r-- | lib/libc/posix1e/acl_support.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/lib/libc/posix1e/acl_support.c b/lib/libc/posix1e/acl_support.c new file mode 100644 index 0000000..b49808f --- /dev/null +++ b/lib/libc/posix1e/acl_support.c @@ -0,0 +1,384 @@ +/*- + * Copyright (c) 1999, 2000, 2001 Robert N. M. Watson + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ +/* + * Support functionality for the POSIX.1e ACL interface + * These calls are intended only to be called within the library. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include "namespace.h" +#include <sys/acl.h> +#include "un-namespace.h" +#include <errno.h> +#include <grp.h> +#include <pwd.h> +#include <stdio.h> +#include <stdlib.h> + +#include "acl_support.h" + +#define ACL_STRING_PERM_WRITE 'w' +#define ACL_STRING_PERM_READ 'r' +#define ACL_STRING_PERM_EXEC 'x' +#define ACL_STRING_PERM_NONE '-' + +/* + * _posix1e_acl_entry_compare -- compare two acl_entry structures to + * determine the order they should appear in. Used by _posix1e_acl_sort to + * sort ACL entries into the kernel-desired order -- i.e., the order useful + * for evaluation and O(n) validity checking. Beter to have an O(nlogn) sort + * in userland and an O(n) in kernel than to have both in kernel. + */ +typedef int (*compare)(const void *, const void *); +static int +_posix1e_acl_entry_compare(struct acl_entry *a, struct acl_entry *b) +{ + /* + * First, sort between tags -- conveniently defined in the correct + * order for verification. + */ + if (a->ae_tag < b->ae_tag) + return (-1); + if (a->ae_tag > b->ae_tag) + return (1); + + /* + * Next compare uids/gids on appropriate types. + */ + + if (a->ae_tag == ACL_USER || a->ae_tag == ACL_GROUP) { + if (a->ae_id < b->ae_id) + return (-1); + if (a->ae_id > b->ae_id) + return (1); + + /* shouldn't be equal, fall through to the invalid case */ + } + + /* + * Don't know how to sort multiple entries of the rest--either it's + * a bad entry, or there shouldn't be more than one. Ignore and the + * validity checker can get it later. + */ + return (0); +} + +/* + * _posix1e_acl_sort -- sort ACL entries in POSIX.1e-formatted ACLs + * Give the opportunity to fail, although we don't currently have a way + * to fail. + */ +int +_posix1e_acl_sort(acl_t acl) +{ + struct acl *acl_int; + + acl_int = &acl->ats_acl; + + qsort(&acl_int->acl_entry[0], acl_int->acl_cnt, + sizeof(struct acl_entry), (compare) _posix1e_acl_entry_compare); + + return (0); +} + +/* + * acl_posix1e -- in what situations should we acl_sort before submission? + * We apply posix1e ACL semantics for any ACL of type ACL_TYPE_ACCESS or + * ACL_TYPE_DEFAULT + */ +int +_posix1e_acl(acl_t acl, acl_type_t type) +{ + + return ((type == ACL_TYPE_ACCESS) || (type == ACL_TYPE_DEFAULT)); +} + +/* + * _posix1e_acl_check -- given an ACL, check its validity. This is mirrored + * from code in sys/kern/kern_acl.c, and if changes are made in one, they + * should be made in the other also. This copy of acl_check is made + * available * in userland for the benefit of processes wanting to check ACLs + * for validity before submitting them to the kernel, or for performing + * in userland file system checking. Needless to say, the kernel makes + * the real checks on calls to get/setacl. + * + * See the comments in kernel for explanation -- just briefly, it assumes + * an already sorted ACL, and checks based on that assumption. The + * POSIX.1e interface, acl_valid(), will perform the sort before calling + * this. Returns 0 on success, EINVAL on failure. + */ +int +_posix1e_acl_check(acl_t acl) +{ + struct acl *acl_int; + struct acl_entry *entry; /* current entry */ + uid_t obj_uid=-1, obj_gid=-1, highest_uid=0, highest_gid=0; + int stage = ACL_USER_OBJ; + int i = 0; + int count_user_obj=0, count_user=0, count_group_obj=0, + count_group=0, count_mask=0, count_other=0; + + acl_int = &acl->ats_acl; + + /* printf("_posix1e_acl_check: checking acl with %d entries\n", + acl->acl_cnt); */ + while (i < acl_int->acl_cnt) { + entry = &acl_int->acl_entry[i]; + + if ((entry->ae_perm | ACL_PERM_BITS) != ACL_PERM_BITS) + return (EINVAL); + + switch(entry->ae_tag) { + case ACL_USER_OBJ: + /* printf("_posix1e_acl_check: %d: ACL_USER_OBJ\n", + i); */ + if (stage > ACL_USER_OBJ) + return (EINVAL); + stage = ACL_USER; + count_user_obj++; + obj_uid = entry->ae_id; + break; + + case ACL_USER: + /* printf("_posix1e_acl_check: %d: ACL_USER\n", i); */ + if (stage > ACL_USER) + return (EINVAL); + stage = ACL_USER; + if (entry->ae_id == obj_uid) + return (EINVAL); + if (count_user && (entry->ae_id <= highest_uid)) + return (EINVAL); + highest_uid = entry->ae_id; + count_user++; + break; + + case ACL_GROUP_OBJ: + /* printf("_posix1e_acl_check: %d: ACL_GROUP_OBJ\n", + i); */ + if (stage > ACL_GROUP_OBJ) + return (EINVAL); + stage = ACL_GROUP; + count_group_obj++; + obj_gid = entry->ae_id; + break; + + case ACL_GROUP: + /* printf("_posix1e_acl_check: %d: ACL_GROUP\n", i); */ + if (stage > ACL_GROUP) + return (EINVAL); + stage = ACL_GROUP; + if (entry->ae_id == obj_gid) + return (EINVAL); + if (count_group && (entry->ae_id <= highest_gid)) + return (EINVAL); + highest_gid = entry->ae_id; + count_group++; + break; + + case ACL_MASK: + /* printf("_posix1e_acl_check: %d: ACL_MASK\n", i); */ + if (stage > ACL_MASK) + return (EINVAL); + stage = ACL_MASK; + count_mask++; + break; + + case ACL_OTHER: + /* printf("_posix1e_acl_check: %d: ACL_OTHER\n", i); */ + if (stage > ACL_OTHER) + return (EINVAL); + stage = ACL_OTHER; + count_other++; + break; + + default: + /* printf("_posix1e_acl_check: %d: INVALID\n", i); */ + return (EINVAL); + } + i++; + } + + if (count_user_obj != 1) + return (EINVAL); + + if (count_group_obj != 1) + return (EINVAL); + + if (count_mask != 0 && count_mask != 1) + return (EINVAL); + + if (count_other != 1) + return (EINVAL); + + return (0); +} + + +/* + * Given a uid/gid, return a username/groupname for the text form of an ACL. + * Note that we truncate user and group names, rather than error out, as + * this is consistent with other tools manipulating user and group names. + * XXX NOT THREAD SAFE, RELIES ON GETPWUID, GETGRGID + * XXX USES *PW* AND *GR* WHICH ARE STATEFUL AND THEREFORE THIS ROUTINE + * MAY HAVE SIDE-EFFECTS + */ +int +_posix1e_acl_id_to_name(acl_tag_t tag, uid_t id, ssize_t buf_len, char *buf) +{ + struct group *g; + struct passwd *p; + int i; + + switch(tag) { + case ACL_USER: + p = getpwuid(id); + if (!p) + i = snprintf(buf, buf_len, "%d", id); + else + i = snprintf(buf, buf_len, "%s", p->pw_name); + + if (i < 0) { + errno = ENOMEM; + return (-1); + } + return (0); + + case ACL_GROUP: + g = getgrgid(id); + if (g == NULL) + i = snprintf(buf, buf_len, "%d", id); + else + i = snprintf(buf, buf_len, "%s", g->gr_name); + + if (i < 0) { + errno = ENOMEM; + return (-1); + } + return (0); + + default: + return (EINVAL); + } +} + +/* + * Given a right-shifted permission (i.e., direct ACL_PERM_* mask), fill + * in a string describing the permissions. + */ +int +_posix1e_acl_perm_to_string(acl_perm_t perm, ssize_t buf_len, char *buf) +{ + + if (buf_len < _POSIX1E_ACL_STRING_PERM_MAXSIZE + 1) { + errno = ENOMEM; + return (-1); + } + + if ((perm | ACL_PERM_BITS) != ACL_PERM_BITS) { + errno = EINVAL; + return (-1); + } + + buf[3] = 0; /* null terminate */ + + if (perm & ACL_READ) + buf[0] = ACL_STRING_PERM_READ; + else + buf[0] = ACL_STRING_PERM_NONE; + + if (perm & ACL_WRITE) + buf[1] = ACL_STRING_PERM_WRITE; + else + buf[1] = ACL_STRING_PERM_NONE; + + if (perm & ACL_EXECUTE) + buf[2] = ACL_STRING_PERM_EXEC; + else + buf[2] = ACL_STRING_PERM_NONE; + + return (0); +} + +/* + * given a string, return a permission describing it + */ +int +_posix1e_acl_string_to_perm(char *string, acl_perm_t *perm) +{ + acl_perm_t myperm = ACL_PERM_NONE; + char *ch; + + ch = string; + while (*ch) { + switch(*ch) { + case ACL_STRING_PERM_READ: + myperm |= ACL_READ; + break; + case ACL_STRING_PERM_WRITE: + myperm |= ACL_WRITE; + break; + case ACL_STRING_PERM_EXEC: + myperm |= ACL_EXECUTE; + break; + case ACL_STRING_PERM_NONE: + break; + default: + return (EINVAL); + } + ch++; + } + + *perm = myperm; + return (0); +} + +/* + * Add an ACL entry without doing much checking, et al + */ +int +_posix1e_acl_add_entry(acl_t acl, acl_tag_t tag, uid_t id, acl_perm_t perm) +{ + struct acl *acl_int; + struct acl_entry *e; + + acl_int = &acl->ats_acl; + + if (acl_int->acl_cnt >= ACL_MAX_ENTRIES) { + errno = ENOMEM; + return (-1); + } + + e = &(acl_int->acl_entry[acl_int->acl_cnt]); + e->ae_perm = perm; + e->ae_tag = tag; + e->ae_id = id; + acl_int->acl_cnt++; + + return (0); +} |
