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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd 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 2 of the License, or
(at your option) any later version.
systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <sys/acl.h>
#include <acl/libacl.h>
#include <errno.h>
#include <string.h>
#include "logind-acl.h"
#include "util.h"
static int find_acl(acl_t acl, uid_t uid, acl_entry_t *entry) {
acl_entry_t i;
int found;
assert(acl);
assert(entry);
for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
found > 0;
found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
acl_tag_t tag;
uid_t *u;
bool b;
if (acl_get_tag_type(i, &tag) < 0)
return -errno;
if (tag != ACL_USER)
continue;
u = acl_get_qualifier(i);
if (!u)
return -errno;
b = *u == uid;
free(u);
if (b) {
*entry = i;
return 1;
}
}
if (found < 0)
return -errno;
return 0;
}
static int flush_acl(acl_t acl) {
acl_entry_t i;
int found;
bool changed = false;
assert(acl);
for (found = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
found > 0;
found = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
acl_tag_t tag;
if (acl_get_tag_type(i, &tag) < 0)
return -errno;
if (tag != ACL_USER)
continue;
if (acl_delete_entry(acl, i) < 0)
return -errno;
changed = true;
}
if (found < 0)
return -errno;
return changed;
}
int devnode_acl(const char *path,
bool flush,
bool del, uid_t old_uid,
bool add, uid_t new_uid) {
acl_t acl;
int r;
bool changed = false;
assert(path);
acl = acl_get_file(path, ACL_TYPE_ACCESS);
if (!acl)
return -errno;
if (flush) {
r = flush_acl(acl);
if (r < 0)
goto finish;
if (r > 0)
changed = true;
} else if (del && old_uid > 0) {
acl_entry_t entry;
r = find_acl(acl, old_uid, &entry);
if (r < 0)
goto finish;
if (r > 0) {
if (acl_delete_entry(acl, entry) < 0) {
r = -errno;
goto finish;
}
changed = true;
}
}
if (add && new_uid > 0) {
acl_entry_t entry;
acl_permset_t permset;
int rd, wt;
r = find_acl(acl, new_uid, &entry);
if (r < 0)
goto finish;
if (r == 0) {
if (acl_create_entry(&acl, &entry) < 0) {
r = -errno;
goto finish;
}
if (acl_set_tag_type(entry, ACL_USER) < 0 ||
acl_set_qualifier(entry, &new_uid) < 0) {
r = -errno;
goto finish;
}
}
if (acl_get_permset(entry, &permset) < 0) {
r = -errno;
goto finish;
}
rd = acl_get_perm(permset, ACL_READ);
if (rd < 0) {
r = -errno;
goto finish;
}
wt = acl_get_perm(permset, ACL_WRITE);
if (wt < 0) {
r = -errno;
goto finish;
}
if (!rd || !wt) {
if (acl_add_perm(permset, ACL_READ|ACL_WRITE) < 0) {
r = -errno;
goto finish;
}
changed = true;
}
}
if (!changed)
goto finish;
if (acl_calc_mask(&acl) < 0) {
r = -errno;
goto finish;
}
if (acl_set_file(path, ACL_TYPE_ACCESS, acl) < 0) {
r = -errno;
goto finish;
}
r = 0;
finish:
acl_free(acl);
return r;
}
int devnode_acl_all(struct udev *udev,
const char *seat,
bool flush,
bool del, uid_t old_uid,
bool add, uid_t new_uid) {
struct udev_list_entry *item = NULL, *first = NULL;
struct udev_enumerate *e;
int r;
assert(udev);
if (!seat)
seat = "seat0";
e = udev_enumerate_new(udev);
if (!e)
return -ENOMEM;
r = udev_enumerate_add_match_tag(e, "uaccess");
if (r < 0)
goto finish;
r = udev_enumerate_add_match_tag(e, seat);
if (r < 0)
goto finish;
r = udev_enumerate_scan_devices(e);
if (r < 0)
goto finish;
first = udev_enumerate_get_list_entry(e);
udev_list_entry_foreach(item, first) {
struct udev_device *d;
const char *node, *sn;
d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
if (!d) {
r = -ENOMEM;
goto finish;
}
sn = udev_device_get_property_value(d, "SEAT");
if (!sn)
sn = "seat0";
if (!streq(seat, sn)) {
udev_device_unref(d);
continue;
}
node = udev_device_get_devnode(d);
udev_device_unref(d);
if (!node) {
r = -ENOMEM;
goto finish;
}
r = devnode_acl(node, flush, del, old_uid, add, new_uid);
if (r < 0)
goto finish;
}
finish:
if (e)
udev_enumerate_unref(e);
return r;
}
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