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Systemd/src/shared/userdb.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sys/auxv.h>
#include "dirent-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "group-record-nss.h"
#include "missing_syscall.h"
#include "parse-util.h"
#include "set.h"
#include "socket-util.h"
#include "strv.h"
#include "user-record-nss.h"
#include "user-util.h"
#include "userdb.h"
#include "varlink.h"
DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(link_hash_ops, void, trivial_hash_func, trivial_compare_func, Varlink, varlink_unref);
typedef enum LookupWhat {
LOOKUP_USER,
LOOKUP_GROUP,
LOOKUP_MEMBERSHIP,
_LOOKUP_WHAT_MAX,
} LookupWhat;
struct UserDBIterator {
LookupWhat what;
Set *links;
bool nss_covered:1;
bool nss_iterating:1;
bool synthesize_root:1;
bool synthesize_nobody:1;
int error;
int nss_lock;
unsigned n_found;
sd_event *event;
UserRecord *found_user; /* when .what == LOOKUP_USER */
GroupRecord *found_group; /* when .what == LOOKUP_GROUP */
char *found_user_name, *found_group_name; /* when .what == LOOKUP_MEMBERSHIP */
char **members_of_group;
size_t index_members_of_group;
char *filter_user_name;
};
UserDBIterator* userdb_iterator_free(UserDBIterator *iterator) {
if (!iterator)
return NULL;
set_free(iterator->links);
switch (iterator->what) {
case LOOKUP_USER:
user_record_unref(iterator->found_user);
if (iterator->nss_iterating)
endpwent();
break;
case LOOKUP_GROUP:
group_record_unref(iterator->found_group);
if (iterator->nss_iterating)
endgrent();
break;
case LOOKUP_MEMBERSHIP:
free(iterator->found_user_name);
free(iterator->found_group_name);
strv_free(iterator->members_of_group);
free(iterator->filter_user_name);
if (iterator->nss_iterating)
endgrent();
break;
default:
assert_not_reached("Unexpected state?");
}
sd_event_unref(iterator->event);
safe_close(iterator->nss_lock);
return mfree(iterator);
}
static UserDBIterator* userdb_iterator_new(LookupWhat what) {
UserDBIterator *i;
assert(what >= 0);
assert(what < _LOOKUP_WHAT_MAX);
i = new(UserDBIterator, 1);
if (!i)
return NULL;
*i = (UserDBIterator) {
.what = what,
.nss_lock = -1,
};
return i;
}
struct user_group_data {
JsonVariant *record;
bool incomplete;
};
static void user_group_data_release(struct user_group_data *d) {
json_variant_unref(d->record);
}
static int userdb_on_query_reply(
Varlink *link,
JsonVariant *parameters,
const char *error_id,
VarlinkReplyFlags flags,
void *userdata) {
UserDBIterator *iterator = userdata;
int r;
assert(iterator);
if (error_id) {
log_debug("Got lookup error: %s", error_id);
if (STR_IN_SET(error_id,
"io.systemd.UserDatabase.NoRecordFound",
"io.systemd.UserDatabase.ConflictingRecordFound"))
r = -ESRCH;
else if (streq(error_id, "io.systemd.UserDatabase.ServiceNotAvailable"))
r = -EHOSTDOWN;
else if (streq(error_id, VARLINK_ERROR_TIMEOUT))
r = -ETIMEDOUT;
else
r = -EIO;
goto finish;
}
switch (iterator->what) {
case LOOKUP_USER: {
_cleanup_(user_group_data_release) struct user_group_data user_data = {};
static const JsonDispatch dispatch_table[] = {
{ "record", _JSON_VARIANT_TYPE_INVALID, json_dispatch_variant, offsetof(struct user_group_data, record), 0 },
{ "incomplete", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(struct user_group_data, incomplete), 0 },
{}
};
_cleanup_(user_record_unrefp) UserRecord *hr = NULL;
assert_se(!iterator->found_user);
r = json_dispatch(parameters, dispatch_table, NULL, 0, &user_data);
if (r < 0)
goto finish;
if (!user_data.record) {
r = log_debug_errno(SYNTHETIC_ERRNO(EIO), "Reply is missing record key");
goto finish;
}
hr = user_record_new();
if (!hr) {
r = -ENOMEM;
goto finish;
}
r = user_record_load(hr, user_data.record, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
if (r < 0)
goto finish;
if (!hr->service) {
r = log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "User record does not carry service information, refusing.");
goto finish;
}
hr->incomplete = user_data.incomplete;
/* We match the root user by the name since the name is our primary key. We match the nobody
* use by UID though, since the name might differ on OSes */
if (streq_ptr(hr->user_name, "root"))
iterator->synthesize_root = false;
if (hr->uid == UID_NOBODY)
iterator->synthesize_nobody = false;
iterator->found_user = TAKE_PTR(hr);
iterator->n_found++;
/* More stuff coming? then let's just exit cleanly here */
if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
return 0;
/* Otherwise, let's remove this link and exit cleanly then */
r = 0;
goto finish;
}
case LOOKUP_GROUP: {
_cleanup_(user_group_data_release) struct user_group_data group_data = {};
static const JsonDispatch dispatch_table[] = {
{ "record", _JSON_VARIANT_TYPE_INVALID, json_dispatch_variant, offsetof(struct user_group_data, record), 0 },
{ "incomplete", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(struct user_group_data, incomplete), 0 },
{}
};
_cleanup_(group_record_unrefp) GroupRecord *g = NULL;
assert_se(!iterator->found_group);
r = json_dispatch(parameters, dispatch_table, NULL, 0, &group_data);
if (r < 0)
goto finish;
if (!group_data.record) {
r = log_debug_errno(SYNTHETIC_ERRNO(EIO), "Reply is missing record key");
goto finish;
}
g = group_record_new();
if (!g) {
r = -ENOMEM;
goto finish;
}
r = group_record_load(g, group_data.record, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
if (r < 0)
goto finish;
if (!g->service) {
r = log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Group record does not carry service information, refusing.");
goto finish;
}
g->incomplete = group_data.incomplete;
if (streq_ptr(g->group_name, "root"))
iterator->synthesize_root = false;
if (g->gid == GID_NOBODY)
iterator->synthesize_nobody = false;
iterator->found_group = TAKE_PTR(g);
iterator->n_found++;
if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
return 0;
r = 0;
goto finish;
}
case LOOKUP_MEMBERSHIP: {
struct membership_data {
const char *user_name;
const char *group_name;
} membership_data = {};
static const JsonDispatch dispatch_table[] = {
{ "userName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(struct membership_data, user_name), JSON_SAFE },
{ "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(struct membership_data, group_name), JSON_SAFE },
{}
};
assert(!iterator->found_user_name);
assert(!iterator->found_group_name);
r = json_dispatch(parameters, dispatch_table, NULL, 0, &membership_data);
if (r < 0)
goto finish;
iterator->found_user_name = mfree(iterator->found_user_name);
iterator->found_group_name = mfree(iterator->found_group_name);
iterator->found_user_name = strdup(membership_data.user_name);
if (!iterator->found_user_name) {
r = -ENOMEM;
goto finish;
}
iterator->found_group_name = strdup(membership_data.group_name);
if (!iterator->found_group_name) {
r = -ENOMEM;
goto finish;
}
iterator->n_found++;
if (FLAGS_SET(flags, VARLINK_REPLY_CONTINUES))
return 0;
r = 0;
goto finish;
}
default:
assert_not_reached("unexpected lookup");
}
finish:
/* If we got one ESRCH, let that win. This way when we do a wild dump we won't be tripped up by bad
* errors if at least one connection ended cleanly */
if (r == -ESRCH || iterator->error == 0)
iterator->error = -r;
assert_se(set_remove(iterator->links, link) == link);
link = varlink_unref(link);
return 0;
}
static int userdb_connect(
UserDBIterator *iterator,
const char *path,
const char *method,
bool more,
JsonVariant *query) {
_cleanup_(varlink_unrefp) Varlink *vl = NULL;
int r;
assert(iterator);
assert(path);
assert(method);
r = varlink_connect_address(&vl, path);
if (r < 0)
return log_debug_errno(r, "Unable to connect to %s: %m", path);
varlink_set_userdata(vl, iterator);
if (!iterator->event) {
r = sd_event_new(&iterator->event);
if (r < 0)
return log_debug_errno(r, "Unable to allocate event loop: %m");
}
r = varlink_attach_event(vl, iterator->event, SD_EVENT_PRIORITY_NORMAL);
if (r < 0)
return log_debug_errno(r, "Failed to attach varlink connection to event loop: %m");
(void) varlink_set_description(vl, path);
r = varlink_bind_reply(vl, userdb_on_query_reply);
if (r < 0)
return log_debug_errno(r, "Failed to bind reply callback: %m");
if (more)
r = varlink_observe(vl, method, query);
else
r = varlink_invoke(vl, method, query);
if (r < 0)
return log_debug_errno(r, "Failed to invoke varlink method: %m");
r = set_ensure_put(&iterator->links, &link_hash_ops, vl);
if (r < 0)
return log_debug_errno(r, "Failed to add varlink connection to set: %m");
TAKE_PTR(vl);
return r;
}
static int userdb_start_query(
UserDBIterator *iterator,
const char *method,
bool more,
JsonVariant *query,
UserDBFlags flags) {
_cleanup_(strv_freep) char **except = NULL, **only = NULL;
_cleanup_(closedirp) DIR *d = NULL;
struct dirent *de;
const char *e;
int r, ret = 0;
assert(iterator);
assert(method);
e = getenv("SYSTEMD_BYPASS_USERDB");
if (e) {
r = parse_boolean(e);
if (r > 0)
return -ENOLINK;
if (r < 0) {
except = strv_split(e, ":");
if (!except)
return -ENOMEM;
}
}
e = getenv("SYSTEMD_ONLY_USERDB");
if (e) {
only = strv_split(e, ":");
if (!only)
return -ENOMEM;
}
/* First, let's talk to the multiplexer, if we can */
if ((flags & (USERDB_AVOID_MULTIPLEXER|USERDB_AVOID_DYNAMIC_USER|USERDB_AVOID_NSS|USERDB_DONT_SYNTHESIZE)) == 0 &&
!strv_contains(except, "io.systemd.Multiplexer") &&
(!only || strv_contains(only, "io.systemd.Multiplexer"))) {
_cleanup_(json_variant_unrefp) JsonVariant *patched_query = json_variant_ref(query);
r = json_variant_set_field_string(&patched_query, "service", "io.systemd.Multiplexer");
if (r < 0)
return log_debug_errno(r, "Unable to set service JSON field: %m");
r = userdb_connect(iterator, "/run/systemd/userdb/io.systemd.Multiplexer", method, more, patched_query);
if (r >= 0) {
iterator->nss_covered = true; /* The multiplexer does NSS */
return 0;
}
}
d = opendir("/run/systemd/userdb/");
if (!d) {
if (errno == ENOENT)
return -ESRCH;
return -errno;
}
FOREACH_DIRENT(de, d, return -errno) {
_cleanup_(json_variant_unrefp) JsonVariant *patched_query = NULL;
_cleanup_free_ char *p = NULL;
bool is_nss;
if (streq(de->d_name, "io.systemd.Multiplexer")) /* We already tried this above, don't try this again */
continue;
if (FLAGS_SET(flags, USERDB_AVOID_DYNAMIC_USER) &&
streq(de->d_name, "io.systemd.DynamicUser"))
continue;
/* Avoid NSS is this is requested. Note that we also skip NSS when we were asked to skip the
* multiplexer, since in that case it's safer to do NSS in the client side emulation below
* (and when we run as part of systemd-userdbd.service we don't want to talk to ourselves
* anyway). */
is_nss = streq(de->d_name, "io.systemd.NameServiceSwitch");
if ((flags & (USERDB_AVOID_NSS|USERDB_AVOID_MULTIPLEXER)) && is_nss)
continue;
if (strv_contains(except, de->d_name))
continue;
if (only && !strv_contains(only, de->d_name))
continue;
p = path_join("/run/systemd/userdb/", de->d_name);
if (!p)
return -ENOMEM;
patched_query = json_variant_ref(query);
r = json_variant_set_field_string(&patched_query, "service", de->d_name);
if (r < 0)
return log_debug_errno(r, "Unable to set service JSON field: %m");
r = userdb_connect(iterator, p, method, more, patched_query);
if (is_nss && r >= 0) /* Turn off fallback NSS if we found the NSS service and could connect
* to it */
iterator->nss_covered = true;
if (ret == 0 && r < 0)
ret = r;
}
if (set_isempty(iterator->links))
return ret; /* propagate last error we saw if we couldn't connect to anything. */
/* We connected to some services, in this case, ignore the ones we failed on */
return 0;
}
static int userdb_process(
UserDBIterator *iterator,
UserRecord **ret_user_record,
GroupRecord **ret_group_record,
char **ret_user_name,
char **ret_group_name) {
int r;
assert(iterator);
for (;;) {
if (iterator->what == LOOKUP_USER && iterator->found_user) {
if (ret_user_record)
*ret_user_record = TAKE_PTR(iterator->found_user);
else
iterator->found_user = user_record_unref(iterator->found_user);
if (ret_group_record)
*ret_group_record = NULL;
if (ret_user_name)
*ret_user_name = NULL;
if (ret_group_name)
*ret_group_name = NULL;
return 0;
}
if (iterator->what == LOOKUP_GROUP && iterator->found_group) {
if (ret_group_record)
*ret_group_record = TAKE_PTR(iterator->found_group);
else
iterator->found_group = group_record_unref(iterator->found_group);
if (ret_user_record)
*ret_user_record = NULL;
if (ret_user_name)
*ret_user_name = NULL;
if (ret_group_name)
*ret_group_name = NULL;
return 0;
}
if (iterator->what == LOOKUP_MEMBERSHIP && iterator->found_user_name && iterator->found_group_name) {
if (ret_user_name)
*ret_user_name = TAKE_PTR(iterator->found_user_name);
else
iterator->found_user_name = mfree(iterator->found_user_name);
if (ret_group_name)
*ret_group_name = TAKE_PTR(iterator->found_group_name);
else
iterator->found_group_name = mfree(iterator->found_group_name);
if (ret_user_record)
*ret_user_record = NULL;
if (ret_group_record)
*ret_group_record = NULL;
return 0;
}
if (set_isempty(iterator->links)) {
if (iterator->error == 0)
return -ESRCH;
return -abs(iterator->error);
}
if (!iterator->event)
return -ESRCH;
r = sd_event_run(iterator->event, UINT64_MAX);
if (r < 0)
return r;
}
}
static int synthetic_root_user_build(UserRecord **ret) {
return user_record_build(
ret,
JSON_BUILD_OBJECT(JSON_BUILD_PAIR("userName", JSON_BUILD_STRING("root")),
JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(0)),
JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(0)),
JSON_BUILD_PAIR("homeDirectory", JSON_BUILD_STRING("/root")),
JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
}
static int synthetic_nobody_user_build(UserRecord **ret) {
return user_record_build(
ret,
JSON_BUILD_OBJECT(JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(NOBODY_USER_NAME)),
JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(UID_NOBODY)),
JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(GID_NOBODY)),
JSON_BUILD_PAIR("shell", JSON_BUILD_STRING(NOLOGIN)),
JSON_BUILD_PAIR("locked", JSON_BUILD_BOOLEAN(true)),
JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
}
int userdb_by_name(const char *name, UserDBFlags flags, UserRecord **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
int r;
if (!valid_user_group_name(name, VALID_USER_RELAX))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(name))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_USER);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", false, query, flags);
if (r >= 0) {
r = userdb_process(iterator, ret, NULL, NULL, NULL);
if (r >= 0)
return r;
}
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
/* Make sure the NSS lookup doesn't recurse back to us. (EBUSY is fine here, it just means we
* already took the lock from our thread, which is totally OK.) */
r = userdb_nss_compat_disable();
if (r >= 0 || r == -EBUSY) {
iterator->nss_lock = r;
/* Client-side NSS fallback */
r = nss_user_record_by_name(name, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
if (r >= 0)
return r;
}
}
if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
if (streq(name, "root"))
return synthetic_root_user_build(ret);
if (streq(name, NOBODY_USER_NAME) && synthesize_nobody())
return synthetic_nobody_user_build(ret);
}
return r;
}
int userdb_by_uid(uid_t uid, UserDBFlags flags, UserRecord **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
int r;
if (!uid_is_valid(uid))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(uid))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_USER);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", false, query, flags);
if (r >= 0) {
r = userdb_process(iterator, ret, NULL, NULL, NULL);
if (r >= 0)
return r;
}
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
r = userdb_nss_compat_disable();
if (r >= 0 || r == -EBUSY) {
iterator->nss_lock = r;
/* Client-side NSS fallback */
r = nss_user_record_by_uid(uid, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
if (r >= 0)
return r;
}
}
if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
if (uid == 0)
return synthetic_root_user_build(ret);
if (uid == UID_NOBODY && synthesize_nobody())
return synthetic_nobody_user_build(ret);
}
return r;
}
int userdb_all(UserDBFlags flags, UserDBIterator **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
int r;
assert(ret);
iterator = userdb_iterator_new(LOOKUP_USER);
if (!iterator)
return -ENOMEM;
iterator->synthesize_root = iterator->synthesize_nobody = !FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE);
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetUserRecord", true, NULL, flags);
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && (r < 0 || !iterator->nss_covered)) {
iterator->nss_lock = userdb_nss_compat_disable();
if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
return iterator->nss_lock;
setpwent();
iterator->nss_iterating = true;
} else if (r < 0)
return r;
*ret = TAKE_PTR(iterator);
return 0;
}
int userdb_iterator_get(UserDBIterator *iterator, UserRecord **ret) {
int r;
assert(iterator);
assert(iterator->what == LOOKUP_USER);
if (iterator->nss_iterating) {
struct passwd *pw;
/* If NSS isn't covered elsewhere, let's iterate through it first, since it probably contains
* the more traditional sources, which are probably good to show first. */
pw = getpwent();
if (pw) {
_cleanup_free_ char *buffer = NULL;
bool incomplete = false;
struct spwd spwd;
if (streq_ptr(pw->pw_name, "root"))
iterator->synthesize_root = false;
if (pw->pw_uid == UID_NOBODY)
iterator->synthesize_nobody = false;
r = nss_spwd_for_passwd(pw, &spwd, &buffer);
if (r < 0) {
log_debug_errno(r, "Failed to acquire shadow entry for user %s, ignoring: %m", pw->pw_name);
incomplete = ERRNO_IS_PRIVILEGE(r);
}
r = nss_passwd_to_user_record(pw, r >= 0 ? &spwd : NULL, ret);
if (r < 0)
return r;
if (ret)
(*ret)->incomplete = incomplete;
return r;
}
if (errno != 0)
log_debug_errno(errno, "Failure to iterate NSS user database, ignoring: %m");
iterator->nss_iterating = false;
endpwent();
}
r = userdb_process(iterator, ret, NULL, NULL, NULL);
if (r < 0) {
if (iterator->synthesize_root) {
iterator->synthesize_root = false;
iterator->n_found++;
return synthetic_root_user_build(ret);
}
if (iterator->synthesize_nobody) {
iterator->synthesize_nobody = false;
iterator->n_found++;
return synthetic_nobody_user_build(ret);
}
}
/* if we found at least one entry, then ignore errors and indicate that we reached the end */
if (r < 0 && iterator->n_found > 0)
return -ESRCH;
return r;
}
static int synthetic_root_group_build(GroupRecord **ret) {
return group_record_build(
ret,
JSON_BUILD_OBJECT(JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING("root")),
JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(0)),
JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
}
static int synthetic_nobody_group_build(GroupRecord **ret) {
return group_record_build(
ret,
JSON_BUILD_OBJECT(JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(NOBODY_GROUP_NAME)),
JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(GID_NOBODY)),
JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("intrinsic"))));
}
int groupdb_by_name(const char *name, UserDBFlags flags, GroupRecord **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
int r;
if (!valid_user_group_name(name, VALID_USER_RELAX))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(name))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_GROUP);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", false, query, flags);
if (r >= 0) {
r = userdb_process(iterator, NULL, ret, NULL, NULL);
if (r >= 0)
return r;
}
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
r = userdb_nss_compat_disable();
if (r >= 0 || r == -EBUSY) {
iterator->nss_lock = r;
r = nss_group_record_by_name(name, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
if (r >= 0)
return r;
}
}
if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
if (streq(name, "root"))
return synthetic_root_group_build(ret);
if (streq(name, NOBODY_GROUP_NAME) && synthesize_nobody())
return synthetic_nobody_group_build(ret);
}
return r;
}
int groupdb_by_gid(gid_t gid, UserDBFlags flags, GroupRecord **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
int r;
if (!gid_is_valid(gid))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(gid))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_GROUP);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", false, query, flags);
if (r >= 0) {
r = userdb_process(iterator, NULL, ret, NULL, NULL);
if (r >= 0)
return r;
}
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && !(iterator && iterator->nss_covered)) {
r = userdb_nss_compat_disable();
if (r >= 0 || r == -EBUSY) {
iterator->nss_lock = r;
r = nss_group_record_by_gid(gid, !FLAGS_SET(flags, USERDB_AVOID_SHADOW), ret);
if (r >= 0)
return r;
}
}
if (!FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE)) {
if (gid == 0)
return synthetic_root_group_build(ret);
if (gid == GID_NOBODY && synthesize_nobody())
return synthetic_nobody_group_build(ret);
}
return r;
}
int groupdb_all(UserDBFlags flags, UserDBIterator **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
int r;
assert(ret);
iterator = userdb_iterator_new(LOOKUP_GROUP);
if (!iterator)
return -ENOMEM;
iterator->synthesize_root = iterator->synthesize_nobody = !FLAGS_SET(flags, USERDB_DONT_SYNTHESIZE);
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetGroupRecord", true, NULL, flags);
if (!FLAGS_SET(flags, USERDB_AVOID_NSS) && (r < 0 || !iterator->nss_covered)) {
iterator->nss_lock = userdb_nss_compat_disable();
if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
return iterator->nss_lock;
setgrent();
iterator->nss_iterating = true;
} if (r < 0)
return r;
*ret = TAKE_PTR(iterator);
return 0;
}
int groupdb_iterator_get(UserDBIterator *iterator, GroupRecord **ret) {
int r;
assert(iterator);
assert(iterator->what == LOOKUP_GROUP);
if (iterator->nss_iterating) {
struct group *gr;
errno = 0;
gr = getgrent();
if (gr) {
_cleanup_free_ char *buffer = NULL;
bool incomplete = false;
struct sgrp sgrp;
if (streq_ptr(gr->gr_name, "root"))
iterator->synthesize_root = false;
if (gr->gr_gid == GID_NOBODY)
iterator->synthesize_nobody = false;
r = nss_sgrp_for_group(gr, &sgrp, &buffer);
if (r < 0) {
log_debug_errno(r, "Failed to acquire shadow entry for group %s, ignoring: %m", gr->gr_name);
incomplete = ERRNO_IS_PRIVILEGE(r);
}
r = nss_group_to_group_record(gr, r >= 0 ? &sgrp : NULL, ret);
if (r < 0)
return r;
if (ret)
(*ret)->incomplete = incomplete;
return r;
}
if (errno != 0)
log_debug_errno(errno, "Failure to iterate NSS group database, ignoring: %m");
iterator->nss_iterating = false;
endgrent();
}
r = userdb_process(iterator, NULL, ret, NULL, NULL);
if (r < 0) {
if (iterator->synthesize_root) {
iterator->synthesize_root = false;
iterator->n_found++;
return synthetic_root_group_build(ret);
}
if (iterator->synthesize_nobody) {
iterator->synthesize_nobody = false;
iterator->n_found++;
return synthetic_nobody_group_build(ret);
}
}
/* if we found at least one entry, then ignore errors and indicate that we reached the end */
if (r < 0 && iterator->n_found > 0)
return -ESRCH;
return r;
}
int membershipdb_by_user(const char *name, UserDBFlags flags, UserDBIterator **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
int r;
assert(ret);
if (!valid_user_group_name(name, VALID_USER_RELAX))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(name))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, query, flags);
if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
goto finish;
iterator->nss_lock = userdb_nss_compat_disable();
if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
return iterator->nss_lock;
iterator->filter_user_name = strdup(name);
if (!iterator->filter_user_name)
return -ENOMEM;
setgrent();
iterator->nss_iterating = true;
r = 0;
finish:
if (r >= 0)
*ret = TAKE_PTR(iterator);
return r;
}
int membershipdb_by_group(const char *name, UserDBFlags flags, UserDBIterator **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *query = NULL;
_cleanup_(group_record_unrefp) GroupRecord *gr = NULL;
int r;
assert(ret);
if (!valid_user_group_name(name, VALID_USER_RELAX))
return -EINVAL;
r = json_build(&query, JSON_BUILD_OBJECT(
JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(name))));
if (r < 0)
return r;
iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, query, flags);
if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
goto finish;
iterator->nss_lock = userdb_nss_compat_disable();
if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
return iterator->nss_lock;
/* We ignore all errors here, since the group might be defined by a userdb native service, and we queried them already above. */
(void) nss_group_record_by_name(name, false, &gr);
if (gr) {
iterator->members_of_group = strv_copy(gr->members);
if (!iterator->members_of_group)
return -ENOMEM;
iterator->index_members_of_group = 0;
iterator->found_group_name = strdup(name);
if (!iterator->found_group_name)
return -ENOMEM;
}
r = 0;
finish:
if (r >= 0)
*ret = TAKE_PTR(iterator);
return r;
}
int membershipdb_all(UserDBFlags flags, UserDBIterator **ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
int r;
assert(ret);
iterator = userdb_iterator_new(LOOKUP_MEMBERSHIP);
if (!iterator)
return -ENOMEM;
r = userdb_start_query(iterator, "io.systemd.UserDatabase.GetMemberships", true, NULL, flags);
if ((r >= 0 && iterator->nss_covered) || FLAGS_SET(flags, USERDB_AVOID_NSS))
goto finish;
iterator->nss_lock = userdb_nss_compat_disable();
if (iterator->nss_lock < 0 && iterator->nss_lock != -EBUSY)
return iterator->nss_lock;
setgrent();
iterator->nss_iterating = true;
r = 0;
finish:
if (r >= 0)
*ret = TAKE_PTR(iterator);
return r;
}
int membershipdb_iterator_get(
UserDBIterator *iterator,
char **ret_user,
char **ret_group) {
int r;
assert(iterator);
for (;;) {
/* If we are iteratring through NSS acquire a new group entry if we haven't acquired one yet. */
if (!iterator->members_of_group) {
struct group *g;
if (!iterator->nss_iterating)
break;
assert(!iterator->found_user_name);
do {
errno = 0;
g = getgrent();
if (!g) {
if (errno != 0)
log_debug_errno(errno, "Failure during NSS group iteration, ignoring: %m");
break;
}
} while (iterator->filter_user_name ? !strv_contains(g->gr_mem, iterator->filter_user_name) :
strv_isempty(g->gr_mem));
if (g) {
r = free_and_strdup(&iterator->found_group_name, g->gr_name);
if (r < 0)
return r;
if (iterator->filter_user_name)
iterator->members_of_group = strv_new(iterator->filter_user_name);
else
iterator->members_of_group = strv_copy(g->gr_mem);
if (!iterator->members_of_group)
return -ENOMEM;
iterator->index_members_of_group = 0;
} else {
iterator->nss_iterating = false;
endgrent();
break;
}
}
assert(iterator->found_group_name);
assert(iterator->members_of_group);
assert(!iterator->found_user_name);
if (iterator->members_of_group[iterator->index_members_of_group]) {
_cleanup_free_ char *cu = NULL, *cg = NULL;
if (ret_user) {
cu = strdup(iterator->members_of_group[iterator->index_members_of_group]);
if (!cu)
return -ENOMEM;
}
if (ret_group) {
cg = strdup(iterator->found_group_name);
if (!cg)
return -ENOMEM;
}
if (ret_user)
*ret_user = TAKE_PTR(cu);
if (ret_group)
*ret_group = TAKE_PTR(cg);
iterator->index_members_of_group++;
return 0;
}
iterator->members_of_group = strv_free(iterator->members_of_group);
iterator->found_group_name = mfree(iterator->found_group_name);
}
r = userdb_process(iterator, NULL, NULL, ret_user, ret_group);
if (r < 0 && iterator->n_found > 0)
return -ESRCH;
return r;
}
int membershipdb_by_group_strv(const char *name, UserDBFlags flags, char ***ret) {
_cleanup_(userdb_iterator_freep) UserDBIterator *iterator = NULL;
_cleanup_strv_free_ char **members = NULL;
int r;
assert(name);
assert(ret);
r = membershipdb_by_group(name, flags, &iterator);
if (r < 0)
return r;
for (;;) {
_cleanup_free_ char *user_name = NULL;
r = membershipdb_iterator_get(iterator, &user_name, NULL);
if (r == -ESRCH)
break;
if (r < 0)
return r;
r = strv_consume(&members, TAKE_PTR(user_name));
if (r < 0)
return r;
}
strv_sort(members);
strv_uniq(members);
*ret = TAKE_PTR(members);
return 0;
}
static int userdb_thread_sockaddr(struct sockaddr_un *ret_sa, socklen_t *ret_salen) {
static const uint8_t
k1[16] = { 0x35, 0xc1, 0x1f, 0x41, 0x59, 0xc6, 0xa0, 0xf9, 0x33, 0x4b, 0x17, 0x3d, 0xb9, 0xf6, 0x14, 0xd9 },
k2[16] = { 0x6a, 0x11, 0x4c, 0x37, 0xe5, 0xa3, 0x8c, 0xa6, 0x93, 0x55, 0x64, 0x8c, 0x93, 0xee, 0xa1, 0x7b };
struct siphash sh;
uint64_t x, y;
pid_t tid;
void *p;
assert(ret_sa);
assert(ret_salen);
/* This calculates an AF_UNIX socket address in the abstract namespace whose existence works as an
* indicator whether to emulate NSS records for complex user records that are also available via the
* varlink protocol. The name of the socket is picked in a way so that:
*
* → it is per-thread (by hashing from the TID)
*
* → is not guessable for foreign processes (by hashing from the — hopefully secret — AT_RANDOM
* value every process gets passed from the kernel
*
* By using a socket the NSS emulation can be nicely turned off for limited amounts of time only,
* simply controlled by the lifetime of the fd itself. By using an AF_UNIX socket in the abstract
* namespace the lock is automatically cleaned up when the process dies abnormally.
*
*/
p = ULONG_TO_PTR(getauxval(AT_RANDOM));
if (!p)
return -EIO;
tid = gettid();
siphash24_init(&sh, k1);
siphash24_compress(p, 16, &sh);
siphash24_compress(&tid, sizeof(tid), &sh);
x = siphash24_finalize(&sh);
siphash24_init(&sh, k2);
siphash24_compress(p, 16, &sh);
siphash24_compress(&tid, sizeof(tid), &sh);
y = siphash24_finalize(&sh);
*ret_sa = (struct sockaddr_un) {
.sun_family = AF_UNIX,
};
sprintf(ret_sa->sun_path + 1, "userdb-%016" PRIx64 "%016" PRIx64, x, y);
*ret_salen = offsetof(struct sockaddr_un, sun_path) + 1 + 7 + 32;
return 0;
}
int userdb_nss_compat_is_enabled(void) {
_cleanup_close_ int fd = -1;
union sockaddr_union sa;
socklen_t salen;
int r;
/* Tests whether the NSS compatibility logic is currently turned on for the invoking thread. Returns
* true if NSS compatibility is turned on, i.e. whether NSS records shall be synthesized from complex
* user records. */
r = userdb_thread_sockaddr(&sa.un, &salen);
if (r < 0)
return r;
fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
/* Try to connect(). This doesn't do anything really, except that it checks whether the socket
* address is bound at all. */
if (connect(fd, &sa.sa, salen) < 0) {
if (errno == ECONNREFUSED) /* the socket is not bound, hence NSS emulation shall be done */
return true;
return -errno;
}
return false;
}
int userdb_nss_compat_disable(void) {
_cleanup_close_ int fd = -1;
union sockaddr_union sa;
socklen_t salen;
int r;
/* Turn off the NSS compatibility logic for the invoking thread. By default NSS records are
* synthesized for all complex user records looked up via NSS. If this call is invoked this is
* disabled for the invoking thread, but only for it. A caller that natively supports the varlink
* user record protocol may use that to turn off the compatibility for NSS lookups. */
r = userdb_thread_sockaddr(&sa.un, &salen);
if (r < 0)
return r;
fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
if (fd < 0)
return -errno;
if (bind(fd, &sa.sa, salen) < 0) {
if (errno == EADDRINUSE) /* lock already taken, convert this into a recognizable error */
return -EBUSY;
return -errno;
}
return TAKE_FD(fd);
}
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