blob: 364356da56222df8cd1f150fb04b87c6aba39f5b [file] [log] [blame] [raw]
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <netdb.h>
#include <nss.h>
#include "sd-bus.h"
#include "sd-login.h"
#include "alloc-util.h"
#include "bus-common-errors.h"
#include "env-util.h"
#include "errno-util.h"
#include "format-util.h"
#include "hostname-util.h"
#include "in-addr-util.h"
#include "macro.h"
#include "memory-util.h"
#include "nss-util.h"
#include "signal-util.h"
#include "string-util.h"
#include "user-util.h"
NSS_GETHOSTBYNAME_PROTOTYPES(mymachines);
NSS_GETPW_PROTOTYPES(mymachines);
NSS_GETGR_PROTOTYPES(mymachines);
#define HOST_UID_LIMIT ((uid_t) UINT32_C(0x10000))
#define HOST_GID_LIMIT ((gid_t) UINT32_C(0x10000))
static int count_addresses(sd_bus_message *m, int af, unsigned *ret) {
unsigned c = 0;
int r;
assert(m);
assert(ret);
while ((r = sd_bus_message_enter_container(m, 'r', "iay")) > 0) {
int family;
r = sd_bus_message_read(m, "i", &family);
if (r < 0)
return r;
r = sd_bus_message_skip(m, "ay");
if (r < 0)
return r;
r = sd_bus_message_exit_container(m);
if (r < 0)
return r;
if (af != AF_UNSPEC && family != af)
continue;
c++;
}
if (r < 0)
return r;
r = sd_bus_message_rewind(m, false);
if (r < 0)
return r;
*ret = c;
return 0;
}
static bool avoid_deadlock(void) {
/* Check whether this lookup might have a chance of deadlocking because we are called from the service manager
* code activating systemd-machined.service. After all, we shouldn't synchronously do lookups to
* systemd-machined if we are required to finish before it can be started. This of course won't detect all
* possible dead locks of this kind, but it should work for the most obvious cases. */
if (geteuid() != 0) /* Ignore the env vars unless we are privileged. */
return false;
return streq_ptr(getenv("SYSTEMD_ACTIVATION_UNIT"), "systemd-machined.service") &&
streq_ptr(getenv("SYSTEMD_ACTIVATION_SCOPE"), "system");
}
enum nss_status _nss_mymachines_gethostbyname4_r(
const char *name,
struct gaih_addrtuple **pat,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp) {
struct gaih_addrtuple *r_tuple, *r_tuple_first = NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
_cleanup_free_ int *ifindices = NULL;
_cleanup_free_ char *class = NULL;
size_t l, ms, idx;
unsigned i = 0, c = 0;
char *r_name;
int n_ifindices, r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(pat);
assert(buffer);
assert(errnop);
assert(h_errnop);
r = sd_machine_get_class(name, &class);
if (r < 0)
goto fail;
if (!streq(class, "container")) {
r = -ENOTTY;
goto fail;
}
n_ifindices = sd_machine_get_ifindices(name, &ifindices);
if (n_ifindices < 0) {
r = n_ifindices;
goto fail;
}
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"GetMachineAddresses",
NULL,
&reply,
"s", name);
if (r < 0)
goto fail;
r = sd_bus_message_enter_container(reply, 'a', "(iay)");
if (r < 0)
goto fail;
r = count_addresses(reply, AF_UNSPEC, &c);
if (r < 0)
goto fail;
if (c <= 0) {
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
l = strlen(name);
ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * c;
if (buflen < ms) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
*h_errnop = NETDB_INTERNAL;
return NSS_STATUS_TRYAGAIN;
}
/* First, append name */
r_name = buffer;
memcpy(r_name, name, l+1);
idx = ALIGN(l+1);
/* Second, append addresses */
r_tuple_first = (struct gaih_addrtuple*) (buffer + idx);
while ((r = sd_bus_message_enter_container(reply, 'r', "iay")) > 0) {
int family;
const void *a;
size_t sz;
r = sd_bus_message_read(reply, "i", &family);
if (r < 0)
goto fail;
r = sd_bus_message_read_array(reply, 'y', &a, &sz);
if (r < 0)
goto fail;
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
if (!IN_SET(family, AF_INET, AF_INET6)) {
r = -EAFNOSUPPORT;
goto fail;
}
if (sz != FAMILY_ADDRESS_SIZE(family)) {
r = -EINVAL;
goto fail;
}
r_tuple = (struct gaih_addrtuple*) (buffer + idx);
r_tuple->next = i == c-1 ? NULL : (struct gaih_addrtuple*) ((char*) r_tuple + ALIGN(sizeof(struct gaih_addrtuple)));
r_tuple->name = r_name;
r_tuple->family = family;
r_tuple->scopeid = n_ifindices == 1 ? ifindices[0] : 0;
memcpy(r_tuple->addr, a, sz);
idx += ALIGN(sizeof(struct gaih_addrtuple));
i++;
}
assert(i == c);
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
assert(idx == ms);
if (*pat)
**pat = *r_tuple_first;
else
*pat = r_tuple_first;
if (ttlp)
*ttlp = 0;
/* Explicitly reset both *h_errnop and h_errno to work around
* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
*h_errnop = NETDB_SUCCESS;
h_errno = 0;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
enum nss_status _nss_mymachines_gethostbyname3_r(
const char *name,
int af,
struct hostent *result,
char *buffer, size_t buflen,
int *errnop, int *h_errnop,
int32_t *ttlp,
char **canonp) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
_cleanup_free_ char *class = NULL;
unsigned c = 0, i = 0;
char *r_name, *r_aliases, *r_addr, *r_addr_list;
size_t l, idx, ms, alen;
int r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(result);
assert(buffer);
assert(errnop);
assert(h_errnop);
if (af == AF_UNSPEC)
af = AF_INET;
if (af != AF_INET && af != AF_INET6) {
r = -EAFNOSUPPORT;
goto fail;
}
r = sd_machine_get_class(name, &class);
if (r < 0)
goto fail;
if (!streq(class, "container")) {
r = -ENOTTY;
goto fail;
}
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"GetMachineAddresses",
NULL,
&reply,
"s", name);
if (r < 0)
goto fail;
r = sd_bus_message_enter_container(reply, 'a', "(iay)");
if (r < 0)
goto fail;
r = count_addresses(reply, af, &c);
if (r < 0)
goto fail;
if (c <= 0) {
*h_errnop = HOST_NOT_FOUND;
return NSS_STATUS_NOTFOUND;
}
alen = FAMILY_ADDRESS_SIZE(af);
l = strlen(name);
ms = ALIGN(l+1) + c * ALIGN(alen) + (c+2) * sizeof(char*);
if (buflen < ms) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
*h_errnop = NETDB_INTERNAL;
return NSS_STATUS_TRYAGAIN;
}
/* First, append name */
r_name = buffer;
memcpy(r_name, name, l+1);
idx = ALIGN(l+1);
/* Second, create aliases array */
r_aliases = buffer + idx;
((char**) r_aliases)[0] = NULL;
idx += sizeof(char*);
/* Third, append addresses */
r_addr = buffer + idx;
while ((r = sd_bus_message_enter_container(reply, 'r', "iay")) > 0) {
int family;
const void *a;
size_t sz;
r = sd_bus_message_read(reply, "i", &family);
if (r < 0)
goto fail;
r = sd_bus_message_read_array(reply, 'y', &a, &sz);
if (r < 0)
goto fail;
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
if (family != af)
continue;
if (sz != alen) {
r = -EINVAL;
goto fail;
}
memcpy(r_addr + i*ALIGN(alen), a, alen);
i++;
}
assert(i == c);
idx += c * ALIGN(alen);
r = sd_bus_message_exit_container(reply);
if (r < 0)
goto fail;
/* Third, append address pointer array */
r_addr_list = buffer + idx;
for (i = 0; i < c; i++)
((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen);
((char**) r_addr_list)[i] = NULL;
idx += (c+1) * sizeof(char*);
assert(idx == ms);
result->h_name = r_name;
result->h_aliases = (char**) r_aliases;
result->h_addrtype = af;
result->h_length = alen;
result->h_addr_list = (char**) r_addr_list;
if (ttlp)
*ttlp = 0;
if (canonp)
*canonp = r_name;
/* Explicitly reset both *h_errnop and h_errno to work around
* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
*h_errnop = NETDB_SUCCESS;
h_errno = 0;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
*h_errnop = NO_RECOVERY;
return NSS_STATUS_UNAVAIL;
}
NSS_GETHOSTBYNAME_FALLBACKS(mymachines);
enum nss_status _nss_mymachines_getpwnam_r(
const char *name,
struct passwd *pwd,
char *buffer, size_t buflen,
int *errnop) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
const char *p, *e, *machine;
uint32_t mapped;
uid_t uid;
size_t l;
int r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(pwd);
p = startswith(name, "vu-");
if (!p)
return NSS_STATUS_NOTFOUND;
e = strrchr(p, '-');
if (!e || e == p)
return NSS_STATUS_NOTFOUND;
if (e - p > HOST_NAME_MAX - 1) /* -1 for the last dash */
return NSS_STATUS_NOTFOUND;
r = parse_uid(e + 1, &uid);
if (r < 0)
return NSS_STATUS_NOTFOUND;
machine = strndupa(p, e - p);
if (!machine_name_is_valid(machine))
return NSS_STATUS_NOTFOUND;
if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
/* Make sure we can't deadlock if we are invoked by dbus-daemon. This way, it won't be able to resolve
* these UIDs, but that should be unproblematic as containers should never be able to connect to a bus
* running on the host. */
return NSS_STATUS_NOTFOUND;
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"MapFromMachineUser",
&error,
&reply,
"su",
machine, (uint32_t) uid);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_USER_MAPPING))
return NSS_STATUS_NOTFOUND;
goto fail;
}
r = sd_bus_message_read(reply, "u", &mapped);
if (r < 0)
goto fail;
/* Refuse to work if the mapped address is in the host UID range, or if there was no mapping at all. */
if (mapped < HOST_UID_LIMIT || mapped == uid)
return NSS_STATUS_NOTFOUND;
l = strlen(name);
if (buflen < l+1) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
memcpy(buffer, name, l+1);
pwd->pw_name = buffer;
pwd->pw_uid = mapped;
pwd->pw_gid = GID_NOBODY;
pwd->pw_gecos = buffer;
pwd->pw_passwd = (char*) "*"; /* locked */
pwd->pw_dir = (char*) "/";
pwd->pw_shell = (char*) NOLOGIN;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
return NSS_STATUS_UNAVAIL;
}
enum nss_status _nss_mymachines_getpwuid_r(
uid_t uid,
struct passwd *pwd,
char *buffer, size_t buflen,
int *errnop) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
const char *machine;
uint32_t mapped;
int r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
if (!uid_is_valid(uid))
return NSS_STATUS_NOTFOUND;
/* We consider all uids < 65536 host uids */
if (uid < HOST_UID_LIMIT)
return NSS_STATUS_NOTFOUND;
if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
return NSS_STATUS_NOTFOUND;
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"MapToMachineUser",
&error,
&reply,
"u",
(uint32_t) uid);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_USER_MAPPING))
return NSS_STATUS_NOTFOUND;
goto fail;
}
r = sd_bus_message_read(reply, "sou", &machine, NULL, &mapped);
if (r < 0)
goto fail;
if (mapped == uid)
return NSS_STATUS_NOTFOUND;
if (snprintf(buffer, buflen, "vu-%s-" UID_FMT, machine, (uid_t) mapped) >= (int) buflen) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
pwd->pw_name = buffer;
pwd->pw_uid = uid;
pwd->pw_gid = GID_NOBODY;
pwd->pw_gecos = buffer;
pwd->pw_passwd = (char*) "*"; /* locked */
pwd->pw_dir = (char*) "/";
pwd->pw_shell = (char*) NOLOGIN;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
return NSS_STATUS_UNAVAIL;
}
#pragma GCC diagnostic ignored "-Wsizeof-pointer-memaccess"
enum nss_status _nss_mymachines_getgrnam_r(
const char *name,
struct group *gr,
char *buffer, size_t buflen,
int *errnop) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
const char *p, *e, *machine;
uint32_t mapped;
uid_t gid;
size_t l;
int r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
assert(name);
assert(gr);
p = startswith(name, "vg-");
if (!p)
return NSS_STATUS_NOTFOUND;
e = strrchr(p, '-');
if (!e || e == p)
return NSS_STATUS_NOTFOUND;
if (e - p > HOST_NAME_MAX - 1) /* -1 for the last dash */
return NSS_STATUS_NOTFOUND;
r = parse_gid(e + 1, &gid);
if (r < 0)
return NSS_STATUS_NOTFOUND;
machine = strndupa(p, e - p);
if (!machine_name_is_valid(machine))
return NSS_STATUS_NOTFOUND;
if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
return NSS_STATUS_NOTFOUND;
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"MapFromMachineGroup",
&error,
&reply,
"su",
machine, (uint32_t) gid);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_GROUP_MAPPING))
return NSS_STATUS_NOTFOUND;
goto fail;
}
r = sd_bus_message_read(reply, "u", &mapped);
if (r < 0)
goto fail;
if (mapped < HOST_GID_LIMIT || mapped == gid)
return NSS_STATUS_NOTFOUND;
l = sizeof(char*) + strlen(name) + 1;
if (buflen < l) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
memzero(buffer, sizeof(char*));
strcpy(buffer + sizeof(char*), name);
gr->gr_name = buffer + sizeof(char*);
gr->gr_gid = mapped;
gr->gr_passwd = (char*) "*"; /* locked */
gr->gr_mem = (char**) buffer;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
return NSS_STATUS_UNAVAIL;
}
enum nss_status _nss_mymachines_getgrgid_r(
gid_t gid,
struct group *gr,
char *buffer, size_t buflen,
int *errnop) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message* reply = NULL;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
const char *machine;
uint32_t mapped;
int r;
PROTECT_ERRNO;
BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
if (!gid_is_valid(gid))
return NSS_STATUS_NOTFOUND;
/* We consider all gids < 65536 host gids */
if (gid < HOST_GID_LIMIT)
return NSS_STATUS_NOTFOUND;
if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
return NSS_STATUS_NOTFOUND;
if (avoid_deadlock()) {
r = -EDEADLK;
goto fail;
}
r = sd_bus_open_system(&bus);
if (r < 0)
goto fail;
r = sd_bus_call_method(bus,
"org.freedesktop.machine1",
"/org/freedesktop/machine1",
"org.freedesktop.machine1.Manager",
"MapToMachineGroup",
&error,
&reply,
"u",
(uint32_t) gid);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_GROUP_MAPPING))
return NSS_STATUS_NOTFOUND;
goto fail;
}
r = sd_bus_message_read(reply, "sou", &machine, NULL, &mapped);
if (r < 0)
goto fail;
if (mapped == gid)
return NSS_STATUS_NOTFOUND;
if (buflen < sizeof(char*) + 1) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
memzero(buffer, sizeof(char*));
if (snprintf(buffer + sizeof(char*), buflen - sizeof(char*), "vg-%s-" GID_FMT, machine, (gid_t) mapped) >= (int) buflen) {
UNPROTECT_ERRNO;
*errnop = ERANGE;
return NSS_STATUS_TRYAGAIN;
}
gr->gr_name = buffer + sizeof(char*);
gr->gr_gid = gid;
gr->gr_passwd = (char*) "*"; /* locked */
gr->gr_mem = (char**) buffer;
return NSS_STATUS_SUCCESS;
fail:
UNPROTECT_ERRNO;
*errnop = -r;
return NSS_STATUS_UNAVAIL;
}