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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include "sd-device.h"
#include "acl-util.h"
#include "alloc-util.h"
#include "device-util.h"
#include "devnode-acl.h"
#include "dirent-util.h"
#include "escape.h"
#include "fd-util.h"
#include "format-util.h"
#include "set.h"
#include "string-util.h"
#include "util.h"
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 = 0;
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 = acl_find_uid(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 = acl_find_uid(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(const char *seat,
bool flush,
bool del, uid_t old_uid,
bool add, uid_t new_uid) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
_cleanup_set_free_free_ Set *nodes = NULL;
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *dent;
sd_device *d;
char *n;
int r;
nodes = set_new(&path_hash_ops);
if (!nodes)
return -ENOMEM;
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
if (isempty(seat))
seat = "seat0";
/* We can only match by one tag in libudev. We choose
* "uaccess" for that. If we could match for two tags here we
* could add the seat name as second match tag, but this would
* be hardly optimizable in libudev, and hence checking the
* second tag manually in our loop is a good solution. */
r = sd_device_enumerator_add_match_tag(e, "uaccess");
if (r < 0)
return r;
FOREACH_DEVICE(e, d) {
const char *node, *sn;
/* Make sure the tag is still in place */
if (sd_device_has_current_tag(d, "uaccess") <= 0)
continue;
if (sd_device_get_property_value(d, "ID_SEAT", &sn) < 0 || isempty(sn))
sn = "seat0";
if (!streq(seat, sn))
continue;
/* In case people mistag devices with nodes, we need to ignore this */
if (sd_device_get_devname(d, &node) < 0)
continue;
log_device_debug(d, "Found udev node %s for seat %s", node, seat);
r = set_put_strdup(&nodes, node);
if (r < 0)
return r;
}
/* udev exports "dead" device nodes to allow module on-demand loading,
* these devices are not known to the kernel at this moment */
dir = opendir("/run/udev/static_node-tags/uaccess");
if (dir) {
FOREACH_DIRENT(dent, dir, return -errno) {
_cleanup_free_ char *unescaped_devname = NULL;
ssize_t l;
l = cunescape(dent->d_name, UNESCAPE_RELAX, &unescaped_devname);
if (l < 0)
return l;
n = path_join("/dev", unescaped_devname);
if (!n)
return -ENOMEM;
log_debug("Found static node %s for seat %s", n, seat);
r = set_consume(nodes, n);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
r = 0;
SET_FOREACH(n, nodes) {
int k;
log_debug("Changing ACLs at %s for seat %s (uid "UID_FMT"→"UID_FMT"%s%s)",
n, seat, old_uid, new_uid,
del ? " del" : "", add ? " add" : "");
k = devnode_acl(n, flush, del, old_uid, add, new_uid);
if (k == -ENOENT)
log_debug("Device %s disappeared while setting ACLs", n);
else if (k < 0 && r == 0)
r = k;
}
return r;
}
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