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pam_systemd.c
1282 lines (1037 loc) · 48.2 KB
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pam_systemd.c
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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <security/_pam_macros.h>
#include <security/pam_ext.h>
#include <security/pam_misc.h>
#include <security/pam_modules.h>
#include <security/pam_modutil.h>
#include <sys/file.h>
#if HAVE_PIDFD_OPEN
#include <sys/pidfd.h>
#endif
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "audit-util.h"
#include "bus-common-errors.h"
#include "bus-error.h"
#include "bus-internal.h"
#include "bus-locator.h"
#include "cap-list.h"
#include "capability-util.h"
#include "cgroup-setup.h"
#include "devnum-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "fs-util.h"
#include "hostname-util.h"
#include "locale-util.h"
#include "login-util.h"
#include "macro.h"
#include "missing_syscall.h"
#include "pam-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "percent-util.h"
#include "process-util.h"
#include "rlimit-util.h"
#include "socket-util.h"
#include "stdio-util.h"
#include "strv.h"
#include "terminal-util.h"
#include "user-util.h"
#include "userdb.h"
#define LOGIN_SLOW_BUS_CALL_TIMEOUT_USEC (2*USEC_PER_MINUTE)
static int parse_caps(
pam_handle_t *handle,
const char *value,
uint64_t *caps) {
bool subtract;
int r;
assert(handle);
assert(value);
if (value[0] == '~') {
subtract = true;
value++;
} else
subtract = false;
for (;;) {
_cleanup_free_ char *s = NULL;
uint64_t b, m;
int c;
/* We can't use spaces as separators here, as PAM's simplistic argument parser doesn't allow
* spaces inside of arguments. We use commas instead (which is similar to cap_from_text(),
* which also uses commas). */
r = extract_first_word(&value, &s, ",", EXTRACT_DONT_COALESCE_SEPARATORS);
if (r < 0)
return r;
if (r == 0)
break;
c = capability_from_name(s);
if (c < 0) {
pam_syslog(handle, LOG_WARNING, "Unknown capability, ignoring: %s", s);
continue;
}
m = UINT64_C(1) << c;
if (!caps)
continue;
if (*caps == UINT64_MAX)
b = subtract ? all_capabilities() : 0;
else
b = *caps;
if (subtract)
*caps = b & ~m;
else
*caps = b | m;
}
return 0;
}
static int parse_argv(
pam_handle_t *handle,
int argc, const char **argv,
const char **class,
const char **type,
const char **desktop,
bool *debug,
uint64_t *default_capability_bounding_set,
uint64_t *default_capability_ambient_set) {
int r;
assert(handle);
assert(argc >= 0);
assert(argc == 0 || argv);
for (int i = 0; i < argc; i++) {
const char *p;
if ((p = startswith(argv[i], "class="))) {
if (class)
*class = p;
} else if ((p = startswith(argv[i], "type="))) {
if (type)
*type = p;
} else if ((p = startswith(argv[i], "desktop="))) {
if (desktop)
*desktop = p;
} else if (streq(argv[i], "debug")) {
if (debug)
*debug = true;
} else if ((p = startswith(argv[i], "debug="))) {
r = parse_boolean(p);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", p);
else if (debug)
*debug = r;
} else if ((p = startswith(argv[i], "default-capability-bounding-set="))) {
r = parse_caps(handle, p, default_capability_bounding_set);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-bounding-set= argument, ignoring: %s", p);
} else if ((p = startswith(argv[i], "default-capability-ambient-set="))) {
r = parse_caps(handle, p, default_capability_ambient_set);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse default-capability-ambient-set= argument, ignoring: %s", p);
} else
pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring.", argv[i]);
}
return 0;
}
static int acquire_user_record(
pam_handle_t *handle,
UserRecord **ret_record) {
_cleanup_(user_record_unrefp) UserRecord *ur = NULL;
const char *username = NULL, *json = NULL;
_cleanup_free_ char *field = NULL;
int r;
assert(handle);
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get user name: @PAMERR@");
if (isempty(username))
return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR, "User name not valid.");
/* If pam_systemd_homed (or some other module) already acquired the user record we can reuse it
* here. */
field = strjoin("systemd-user-record-", username);
if (!field)
return pam_log_oom(handle);
r = pam_get_data(handle, field, (const void**) &json);
if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM user record data: @PAMERR@");
if (r == PAM_SUCCESS && json) {
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
/* Parse cached record */
r = json_parse(json, JSON_PARSE_SENSITIVE, &v, NULL, NULL);
if (r < 0)
return pam_syslog_errno(handle, LOG_ERR, r, "Failed to parse JSON user record: %m");
ur = user_record_new();
if (!ur)
return pam_log_oom(handle);
r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET|USER_RECORD_PERMISSIVE);
if (r < 0)
return pam_syslog_errno(handle, LOG_ERR, r, "Failed to load user record: %m");
/* Safety check if cached record actually matches what we are looking for */
if (!streq_ptr(username, ur->user_name))
return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
"Acquired user record does not match user name.");
} else {
_cleanup_free_ char *formatted = NULL;
/* Request the record ourselves */
r = userdb_by_name(username, 0, &ur);
if (r < 0) {
pam_syslog_errno(handle, LOG_ERR, r, "Failed to get user record: %m");
return PAM_USER_UNKNOWN;
}
r = json_variant_format(ur->json, 0, &formatted);
if (r < 0)
return pam_syslog_errno(handle, LOG_ERR, r, "Failed to format user JSON: %m");
/* And cache it for everyone else */
r = pam_set_data(handle, field, formatted, pam_cleanup_free);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r,
"Failed to set PAM user record data '%s': @PAMERR@", field);
TAKE_PTR(formatted);
}
if (!uid_is_valid(ur->uid))
return pam_syslog_pam_error(handle, LOG_ERR, PAM_SERVICE_ERR,
"Acquired user record does not have a UID.");
if (ret_record)
*ret_record = TAKE_PTR(ur);
return PAM_SUCCESS;
}
static bool display_is_local(const char *display) {
assert(display);
return
display[0] == ':' &&
ascii_isdigit(display[1]);
}
static int socket_from_display(const char *display) {
_cleanup_free_ char *f = NULL;
size_t k;
char *c;
union sockaddr_union sa;
socklen_t sa_len;
_cleanup_close_ int fd = -EBADF;
int r;
assert(display);
if (!display_is_local(display))
return -EINVAL;
k = strspn(display+1, "0123456789");
/* Try abstract socket first. */
f = new(char, STRLEN("@/tmp/.X11-unix/X") + k + 1);
if (!f)
return -ENOMEM;
c = stpcpy(f, "@/tmp/.X11-unix/X");
memcpy(c, display+1, k);
c[k] = 0;
r = sockaddr_un_set_path(&sa.un, f);
if (r < 0)
return r;
sa_len = r;
fd = RET_NERRNO(socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0));
if (fd < 0)
return fd;
r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
if (r >= 0)
return TAKE_FD(fd);
if (r != -ECONNREFUSED)
return r;
/* Try also non-abstract socket. */
r = sockaddr_un_set_path(&sa.un, f + 1);
if (r < 0)
return r;
sa_len = r;
r = RET_NERRNO(connect(fd, &sa.sa, sa_len));
if (r >= 0)
return TAKE_FD(fd);
return r;
}
static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
_cleanup_free_ char *sys_path = NULL, *tty = NULL;
_cleanup_close_ int fd = -EBADF;
struct ucred ucred;
int v, r;
dev_t display_ctty;
assert(display);
assert(vtnr);
/* We deduce the X11 socket from the display name, then use
* SO_PEERCRED to determine the X11 server process, ask for
* the controlling tty of that and if it's a VC then we know
* the seat and the virtual terminal. Sounds ugly, is only
* semi-ugly. */
fd = socket_from_display(display);
if (fd < 0)
return fd;
r = getpeercred(fd, &ucred);
if (r < 0)
return r;
r = get_ctty_devnr(ucred.pid, &display_ctty);
if (r < 0)
return r;
if (asprintf(&sys_path, "/sys/dev/char/" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(display_ctty)) < 0)
return -ENOMEM;
r = readlink_value(sys_path, &tty);
if (r < 0)
return r;
v = vtnr_from_tty(tty);
if (v < 0)
return v;
else if (v == 0)
return -ENOENT;
if (seat)
*seat = "seat0";
*vtnr = (uint32_t) v;
return 0;
}
static int export_legacy_dbus_address(
pam_handle_t *handle,
const char *runtime) {
const char *s;
_cleanup_free_ char *t = NULL;
int r = PAM_BUF_ERR;
/* We need to export $DBUS_SESSION_BUS_ADDRESS because various applications will not connect
* correctly to the bus without it. This setting matches what dbus.socket does for the user
* session using 'systemctl --user set-environment'. We want to have the same configuration
* in processes started from the PAM session.
*
* The setting of the address is guarded by the access() check because it is also possible to compile
* dbus without --enable-user-session, in which case this socket is not used, and
* $DBUS_SESSION_BUS_ADDRESS should not be set. An alternative approach would to not do the access()
* check here, and let applications try on their own, by using "unix:path=%s/bus;autolaunch:". But we
* expect the socket to be present by the time we do this check, so we can just as well check once
* here. */
s = strjoina(runtime, "/bus");
if (access(s, F_OK) < 0)
return PAM_SUCCESS;
if (asprintf(&t, DEFAULT_USER_BUS_ADDRESS_FMT, runtime) < 0)
return pam_log_oom(handle);
r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", t, 0);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set bus variable: @PAMERR@");
return PAM_SUCCESS;
}
static int append_session_memory_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
uint64_t val;
int r;
if (isempty(limit))
return PAM_SUCCESS;
if (streq(limit, "infinity")) {
r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", UINT64_MAX);
if (r < 0)
return pam_bus_log_create_error(handle, r);
return PAM_SUCCESS;
}
r = parse_permyriad(limit);
if (r >= 0) {
r = sd_bus_message_append(m, "(sv)", "MemoryMaxScale", "u", UINT32_SCALE_FROM_PERMYRIAD(r));
if (r < 0)
return pam_bus_log_create_error(handle, r);
return PAM_SUCCESS;
}
r = parse_size(limit, 1024, &val);
if (r >= 0) {
r = sd_bus_message_append(m, "(sv)", "MemoryMax", "t", val);
if (r < 0)
return pam_bus_log_create_error(handle, r);
return PAM_SUCCESS;
}
pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.memory_max, ignoring: %s", limit);
return PAM_SUCCESS;
}
static int append_session_runtime_max_sec(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
usec_t val;
int r;
/* No need to parse "infinity" here, it will be set by default later in scope_init() */
if (isempty(limit) || streq(limit, "infinity"))
return PAM_SUCCESS;
r = parse_sec(limit, &val);
if (r >= 0) {
r = sd_bus_message_append(m, "(sv)", "RuntimeMaxUSec", "t", (uint64_t) val);
if (r < 0)
return pam_bus_log_create_error(handle, r);
} else
pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.runtime_max_sec: %s, ignoring.", limit);
return PAM_SUCCESS;
}
static int append_session_tasks_max(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
uint64_t val;
int r;
/* No need to parse "infinity" here, it will be set unconditionally later in manager_start_scope() */
if (isempty(limit) || streq(limit, "infinity"))
return PAM_SUCCESS;
r = safe_atou64(limit, &val);
if (r >= 0) {
r = sd_bus_message_append(m, "(sv)", "TasksMax", "t", val);
if (r < 0)
return pam_bus_log_create_error(handle, r);
} else
pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.tasks_max, ignoring: %s", limit);
return PAM_SUCCESS;
}
static int append_session_cpu_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
uint64_t val;
int r;
if (isempty(limit))
return PAM_SUCCESS;
r = cg_cpu_weight_parse(limit, &val);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.cpu_weight, ignoring: %s", limit);
else {
r = sd_bus_message_append(m, "(sv)", "CPUWeight", "t", val);
if (r < 0)
return pam_bus_log_create_error(handle, r);
}
return PAM_SUCCESS;
}
static int append_session_io_weight(pam_handle_t *handle, sd_bus_message *m, const char *limit) {
uint64_t val;
int r;
if (isempty(limit))
return PAM_SUCCESS;
r = cg_weight_parse(limit, &val);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse systemd.io_weight, ignoring: %s", limit);
else {
r = sd_bus_message_append(m, "(sv)", "IOWeight", "t", val);
if (r < 0)
return pam_bus_log_create_error(handle, r);
}
return PAM_SUCCESS;
}
static const char* getenv_harder(pam_handle_t *handle, const char *key, const char *fallback) {
const char *v;
assert(handle);
assert(key);
/* Looks for an environment variable, preferably in the environment block associated with the
* specified PAM handle, falling back to the process' block instead. Why check both? Because we want
* to permit configuration of session properties from unit files that invoke PAM services, so that
* PAM services don't have to be reworked to set systemd-specific properties, but these properties
* can still be set from the unit file Environment= block. */
v = pam_getenv(handle, key);
if (!isempty(v))
return v;
/* We use secure_getenv() here, since we might get loaded into su/sudo, which are SUID. Ideally
* they'd clean up the environment before invoking foreign code (such as PAM modules), but alas they
* currently don't (to be precise, they clean up the environment they pass to their children, but
* not their own environ[]). */
v = secure_getenv(key);
if (!isempty(v))
return v;
return fallback;
}
static bool getenv_harder_bool(pam_handle_t *handle, const char *key, bool fallback) {
const char *v;
int r;
assert(handle);
assert(key);
v = getenv_harder(handle, key, NULL);
if (isempty(v))
return fallback;
r = parse_boolean(v);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Boolean environment variable value of '%s' is not valid: %s", key, v);
return fallback;
}
return r;
}
static int update_environment(pam_handle_t *handle, const char *key, const char *value) {
int r;
assert(handle);
assert(key);
/* Updates the environment, but only if there's actually a value set. Also, log about errors */
if (isempty(value))
return PAM_SUCCESS;
r = pam_misc_setenv(handle, key, value, 0);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r,
"Failed to set environment variable %s: @PAMERR@", key);
return PAM_SUCCESS;
}
static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
struct stat st;
assert(handle);
assert(path);
/* Some extra paranoia: let's not set $XDG_RUNTIME_DIR if the directory we'd set it to isn't actually
* set up properly for us. This is supposed to provide a careful safety net for supporting su/sudo
* type transitions: in that case the UID changes, but the session and thus the user owning it
* doesn't change. Since the $XDG_RUNTIME_DIR lifecycle is bound to the session's user being logged
* in at least once we should be particularly careful when setting the environment variable, since
* otherwise we might end up setting $XDG_RUNTIME_DIR to some directory owned by the wrong user. */
if (!path_is_absolute(path)) {
pam_syslog(handle, LOG_ERR, "Provided runtime directory '%s' is not absolute.", path);
goto fail;
}
if (lstat(path, &st) < 0) {
pam_syslog_errno(handle, LOG_ERR, errno, "Failed to stat() runtime directory '%s': %m", path);
goto fail;
}
if (!S_ISDIR(st.st_mode)) {
pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not actually a directory.", path);
goto fail;
}
if (st.st_uid != uid) {
pam_syslog(handle, LOG_ERR, "Runtime directory '%s' is not owned by UID " UID_FMT ", as it should.", path, uid);
goto fail;
}
return true;
fail:
pam_syslog(handle, LOG_WARNING, "Not setting $XDG_RUNTIME_DIR, as the directory is not in order.");
return false;
}
static int pam_putenv_and_log(pam_handle_t *handle, const char *e, bool debug) {
int r;
assert(handle);
assert(e);
r = pam_putenv(handle, e);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r,
"Failed to set PAM environment variable %s: @PAMERR@", e);
pam_debug_syslog(handle, debug, "PAM environment variable %s set based on user record.", e);
return PAM_SUCCESS;
}
static int apply_user_record_settings(
pam_handle_t *handle,
UserRecord *ur,
bool debug,
uint64_t default_capability_bounding_set,
uint64_t default_capability_ambient_set) {
_cleanup_strv_free_ char **langs = NULL;
int r;
assert(handle);
assert(ur);
if (ur->umask != MODE_INVALID) {
umask(ur->umask);
pam_debug_syslog(handle, debug, "Set user umask to %04o based on user record.", ur->umask);
}
STRV_FOREACH(i, ur->environment) {
r = pam_putenv_and_log(handle, *i, debug);
if (r != PAM_SUCCESS)
return r;
}
if (ur->email_address) {
_cleanup_free_ char *joined = NULL;
joined = strjoin("EMAIL=", ur->email_address);
if (!joined)
return pam_log_oom(handle);
r = pam_putenv_and_log(handle, joined, debug);
if (r != PAM_SUCCESS)
return r;
}
if (ur->time_zone) {
if (!timezone_is_valid(ur->time_zone, LOG_DEBUG))
pam_debug_syslog(handle, debug,
"Time zone specified in user record is not valid locally, not setting $TZ.");
else {
_cleanup_free_ char *joined = NULL;
joined = strjoin("TZ=:", ur->time_zone);
if (!joined)
return pam_log_oom(handle);
r = pam_putenv_and_log(handle, joined, debug);
if (r != PAM_SUCCESS)
return r;
}
}
r = user_record_languages(ur, &langs);
if (r < 0)
pam_syslog_errno(handle, LOG_ERR, r,
"Failed to acquire user's language preferences, ignoring: %m");
else if (strv_isempty(langs))
; /* User has no preference set so we do nothing */
else if (locale_is_installed(langs[0]) <= 0)
pam_debug_syslog(handle, debug,
"Preferred languages specified in user record are not installed locally, not setting $LANG or $LANGUAGE.");
else {
_cleanup_free_ char *lang = NULL;
lang = strjoin("LANG=", langs[0]);
if (!lang)
return pam_log_oom(handle);
r = pam_putenv_and_log(handle, lang, debug);
if (r != PAM_SUCCESS)
return r;
if (strv_length(langs) > 1) {
_cleanup_free_ char *joined = NULL, *language = NULL;
joined = strv_join(langs, ":");
if (!joined)
return pam_log_oom(handle);
language = strjoin("LANGUAGE=", joined);
if (!language)
return pam_log_oom(handle);
r = pam_putenv_and_log(handle, language, debug);
if (r != PAM_SUCCESS)
return r;
}
}
if (nice_is_valid(ur->nice_level)) {
if (nice(ur->nice_level) < 0)
pam_syslog_errno(handle, LOG_ERR, errno,
"Failed to set nice level to %i, ignoring: %m", ur->nice_level);
else
pam_debug_syslog(handle, debug,
"Nice level set to %i, based on user record.", ur->nice_level);
}
for (int rl = 0; rl < _RLIMIT_MAX; rl++) {
if (!ur->rlimits[rl])
continue;
r = setrlimit_closest(rl, ur->rlimits[rl]);
if (r < 0)
pam_syslog_errno(handle, LOG_ERR, r,
"Failed to set resource limit %s, ignoring: %m", rlimit_to_string(rl));
else
pam_debug_syslog(handle, debug,
"Resource limit %s set, based on user record.", rlimit_to_string(rl));
}
uint64_t a, b;
a = user_record_capability_ambient_set(ur);
if (a == UINT64_MAX)
a = default_capability_ambient_set;
b = user_record_capability_bounding_set(ur);
if (b == UINT64_MAX)
b = default_capability_bounding_set;
if (a != UINT64_MAX && a != 0) {
a &= b;
r = capability_ambient_set_apply(a, /* also_inherit= */ true);
if (r < 0)
pam_syslog_errno(handle, LOG_ERR, r,
"Failed to set ambient capabilities, ignoring: %m");
}
if (b != UINT64_MAX && !cap_test_all(b)) {
r = capability_bounding_set_drop(b, /* right_now= */ false);
if (r < 0)
pam_syslog_errno(handle, LOG_ERR, r,
"Failed to set bounding capabilities, ignoring: %m");
}
return PAM_SUCCESS;
}
static int configure_runtime_directory(
pam_handle_t *handle,
UserRecord *ur,
const char *rt) {
int r;
assert(handle);
assert(ur);
assert(rt);
if (!validate_runtime_directory(handle, rt, ur->uid))
return PAM_SUCCESS;
r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to set runtime dir: @PAMERR@");
return export_legacy_dbus_address(handle, rt);
}
static uint64_t pick_default_capability_ambient_set(
UserRecord *ur,
const char *service,
const char *seat) {
/* If not configured otherwise, let's enable CAP_WAKE_ALARM for regular users when logging in on a
* seat (i.e. when they are present physically on the device), or when invoked for the systemd --user
* instances. This allows desktops to install CAP_WAKE_ALARM to implement alarm clock apps without
* much fuss. */
return ur &&
user_record_disposition(ur) == USER_REGULAR &&
(streq_ptr(service, "systemd-user") || !isempty(seat)) ? (UINT64_C(1) << CAP_WAKE_ALARM) : UINT64_MAX;
}
typedef struct SessionContext {
const uid_t uid;
const pid_t pid;
const char *service;
const char *type;
const char *class;
const char *desktop;
const char *seat;
const uint32_t vtnr;
const char *tty;
const char *display;
const bool remote;
const char *remote_user;
const char *remote_host;
const char *memory_max;
const char *tasks_max;
const char *cpu_weight;
const char *io_weight;
const char *runtime_max_sec;
} SessionContext;
static int create_session_message(
sd_bus *bus,
pam_handle_t *handle,
const SessionContext *context,
bool avoid_pidfd,
sd_bus_message **ret) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
_cleanup_close_ int pidfd = -EBADF;
int r;
assert(bus);
assert(handle);
assert(context);
assert(ret);
if (!avoid_pidfd) {
pidfd = pidfd_open(getpid_cached(), 0);
if (pidfd < 0 && !ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno))
return -errno;
}
r = bus_message_new_method_call(bus, &m, bus_login_mgr, pidfd >= 0 ? "CreateSessionWithPIDFD" : "CreateSession");
if (r < 0)
return r;
r = sd_bus_message_append(m,
pidfd >= 0 ? "uhsssssussbss" : "uusssssussbss",
(uint32_t) context->uid,
pidfd >= 0 ? pidfd : context->pid,
context->service,
context->type,
context->class,
context->desktop,
context->seat,
context->vtnr,
context->tty,
context->display,
context->remote,
context->remote_user,
context->remote_host);
if (r < 0)
return r;
if (pidfd >= 0) {
r = sd_bus_message_append(m, "t", UINT64_C(0));
if (r < 0)
return r;
}
r = sd_bus_message_open_container(m, 'a', "(sv)");
if (r < 0)
return r;
r = append_session_memory_max(handle, m, context->memory_max);
if (r != PAM_SUCCESS)
return r;
r = append_session_runtime_max_sec(handle, m, context->runtime_max_sec);
if (r != PAM_SUCCESS)
return r;
r = append_session_tasks_max(handle, m, context->tasks_max);
if (r != PAM_SUCCESS)
return r;
r = append_session_cpu_weight(handle, m, context->cpu_weight);
if (r != PAM_SUCCESS)
return r;
r = append_session_io_weight(handle, m, context->io_weight);
if (r != PAM_SUCCESS)
return r;
r = sd_bus_message_close_container(m);
if (r < 0)
return r;
*ret = TAKE_PTR(m);
return 0;
}
_public_ PAM_EXTERN int pam_sm_open_session(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
/* Let's release the D-Bus connection once this function exits, after all the session might live
* quite a long time, and we are not going to process the bus connection in that time, so let's
* better close before the daemon kicks us off because we are not processing anything. */
_cleanup_(pam_bus_data_disconnectp) PamBusData *d = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
const char
*id, *object_path, *runtime_path,
*service = NULL,
*tty = NULL, *display = NULL,
*remote_user = NULL, *remote_host = NULL,
*seat = NULL,
*type = NULL, *class = NULL,
*class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL, *desktop_pam = NULL,
*memory_max = NULL, *tasks_max = NULL, *cpu_weight = NULL, *io_weight = NULL, *runtime_max_sec = NULL;
uint64_t default_capability_bounding_set = UINT64_MAX, default_capability_ambient_set = UINT64_MAX;
_cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
_cleanup_(user_record_unrefp) UserRecord *ur = NULL;
int session_fd = -EBADF, existing, r;
bool debug = false, remote, incomplete;
uint32_t vtnr = 0;
uid_t original_uid;
assert(handle);
pam_log_setup();
if (parse_argv(handle,
argc, argv,
&class_pam,
&type_pam,
&desktop_pam,
&debug,
&default_capability_bounding_set,
&default_capability_ambient_set) < 0)
return PAM_SESSION_ERR;
pam_debug_syslog(handle, debug, "pam-systemd initializing");
r = acquire_user_record(handle, &ur);
if (r != PAM_SUCCESS)
return r;
/* Make most of this a NOP on non-logind systems */
if (!logind_running())
goto success;
r = pam_get_item_many(
handle,
PAM_SERVICE, &service,
PAM_XDISPLAY, &display,
PAM_TTY, &tty,
PAM_RUSER, &remote_user,
PAM_RHOST, &remote_host);
if (r != PAM_SUCCESS)
return pam_syslog_pam_error(handle, LOG_ERR, r, "Failed to get PAM items: @PAMERR@");
seat = getenv_harder(handle, "XDG_SEAT", NULL);
cvtnr = getenv_harder(handle, "XDG_VTNR", NULL);
type = getenv_harder(handle, "XDG_SESSION_TYPE", type_pam);
class = getenv_harder(handle, "XDG_SESSION_CLASS", class_pam);
desktop = getenv_harder(handle, "XDG_SESSION_DESKTOP", desktop_pam);
incomplete = getenv_harder_bool(handle, "XDG_SESSION_INCOMPLETE", false);
if (streq_ptr(service, "systemd-user")) {
/* If we detect that we are running in the "systemd-user" PAM stack, then let's patch the class to
* 'manager' if not set, simply for robustness reasons. */
type = "unspecified";
class = IN_SET(user_record_disposition(ur), USER_INTRINSIC, USER_SYSTEM, USER_DYNAMIC) ?
"manager-early" : "manager";
tty = NULL;
} else if (tty && strchr(tty, ':')) {
/* A tty with a colon is usually an X11 display, placed there to show up in utmp. We rearrange things
* and don't pretend that an X display was a tty. */
if (isempty(display))
display = tty;
tty = NULL;
} else if (streq_ptr(tty, "cron")) {
/* cron is setting PAM_TTY to "cron" for some reason (the commit carries no information why, but
* probably because it wants to set it to something as pam_time/pam_access/… require PAM_TTY to be set
* (as they otherwise even try to update it!) — but cron doesn't actually allocate a TTY for its forked
* off processes.) */
type = "unspecified";
class = "background";
tty = NULL;
} else if (streq_ptr(tty, "ssh")) {
/* ssh has been setting PAM_TTY to "ssh" (for the same reason as cron does this, see above. For further
* details look for "PAM_TTY_KLUDGE" in the openssh sources). */