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pam_systemd: do not set XDG_RUNTIME_DIR if the session's original user is not the same as the newly logged in one

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It's better not to set any XDG_RUNTIME_DIR at all rather than one of a
different user. So let's do this.

This changes the bus call parameters of CreateSession(), but that is
explicitly an internal API hence should be fine. Note however, that a
logind restart (the way the RPM postinst scriptlets do it) is necessary
to make things work again.
This commit is contained in:
Lennart Poettering 2013-11-26 05:05:00 +01:00
parent 898d5c9137
commit baae0358f3
3 changed files with 59 additions and 59 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
src/login/logind-dbus.c
View file

@ -568,11 +568,12 @@ static int method_create_session(sd_bus *bus, sd_bus_message *message, void *use
return -ENOMEM;
return sd_bus_reply_method_return(
message, "soshsub",
message, "soshusub",
session->id,
path,
session->user->runtime_path,
fifo_fd,
(uint32_t) session->user->uid,
session->seat ? session->seat->id : "",
(uint32_t) session->vtnr,
true);
@ -1855,7 +1856,7 @@ const sd_bus_vtable manager_vtable[] = {
SD_BUS_METHOD("ListUsers", NULL, "a(uso)", method_list_users, 0),
SD_BUS_METHOD("ListSeats", NULL, "a(so)", method_list_seats, 0),
SD_BUS_METHOD("ListInhibitors", NULL, "a(ssssuu)", method_list_inhibitors, 0),
SD_BUS_METHOD("CreateSession", "uussssussbssa(sv)", "soshsub", method_create_session, 0),
SD_BUS_METHOD("CreateSession", "uussssussbssa(sv)", "soshusub", method_create_session, 0),
SD_BUS_METHOD("ReleaseSession", "s", NULL, method_release_session, 0),
SD_BUS_METHOD("ActivateSession", "s", NULL, method_activate_session, 0),
SD_BUS_METHOD("ActivateSessionOnSeat", "ss", NULL, method_activate_session_on_seat, 0),

4
src/login/logind-session-dbus.c
View file

@ -667,12 +667,12 @@ int session_send_create_reply(Session *s, sd_bus_error *error) {
(uint32_t) s->vtnr);
return sd_bus_reply_method_return(
c,
"soshsub",
c, "soshusub",
s->id,
p,
s->user->runtime_path,
fifo_fd,
(uint32_t) s->user->uid,
s->seat ? s->seat->id : "",
(uint32_t) s->vtnr,
false);

109
src/login/pam-module.c
View file

@ -42,10 +42,11 @@
#include "fileio.h"
#include "bus-error.h"
static int parse_argv(pam_handle_t *handle,
int argc, const char **argv,
const char **class,
bool *debug) {
static int parse_argv(
pam_handle_t *handle,
int argc, const char **argv,
const char **class,
bool *debug) {
unsigned i;
@ -83,31 +84,24 @@ static int get_user_data(
const char *username = NULL;
struct passwd *pw = NULL;
uid_t uid;
int r;
assert(handle);
assert(ret_username);
assert(ret_pw);
r = audit_loginuid_from_pid(0, &uid);
if (r >= 0)
pw = pam_modutil_getpwuid(handle, uid);
else {
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user name.");
return r;
}
if (isempty(username)) {
pam_syslog(handle, LOG_ERR, "User name not valid.");
return PAM_AUTH_ERR;
}
pw = pam_modutil_getpwnam(handle, username);
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user name.");
return r;
}
if (isempty(username)) {
pam_syslog(handle, LOG_ERR, "User name not valid.");
return PAM_AUTH_ERR;
}
pw = pam_modutil_getpwnam(handle, username);
if (!pw) {
pam_syslog(handle, LOG_ERR, "Failed to get user data.");
return PAM_USER_UNKNOWN;
@ -120,16 +114,14 @@ static int get_user_data(
}
static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
_cleanup_free_ char *p = NULL;
int r;
_cleanup_close_ int fd = -1;
union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
};
_cleanup_free_ char *p = NULL, *tty = NULL;
_cleanup_close_ int fd = -1;
struct ucred ucred;
socklen_t l;
_cleanup_free_ char *tty = NULL;
int v;
int v, r;
assert(display);
assert(vtnr);
@ -191,15 +183,13 @@ _public_ PAM_EXTERN int pam_sm_open_session(
*class_pam = NULL, *cvtnr = NULL;
_cleanup_bus_unref_ sd_bus *bus = NULL;
int session_fd = -1, existing, r;
uint32_t uid, pid, vtnr = 0;
bool debug = false, remote;
struct passwd *pw;
uint32_t vtnr = 0;
uid_t original_uid;
assert(handle);
if (debug)
pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
/* Make this a NOP on non-logind systems */
if (!logind_running())
return PAM_SUCCESS;
@ -210,6 +200,9 @@ _public_ PAM_EXTERN int pam_sm_open_session(
&debug) < 0)
return PAM_SESSION_ERR;
if (debug)
pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
r = get_user_data(handle, &username, &pw);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user data.");
@ -248,9 +241,6 @@ _public_ PAM_EXTERN int pam_sm_open_session(
/* Otherwise, we ask logind to create a session for us */
uid = pw->pw_uid;
pid = getpid();
pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
pam_get_item(handle, PAM_TTY, (const void**) &tty);
pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
@ -264,12 +254,8 @@ _public_ PAM_EXTERN int pam_sm_open_session(
if (isempty(cvtnr))
cvtnr = getenv("XDG_VTNR");
service = strempty(service);
tty = strempty(tty);
display = strempty(display);
remote_user = strempty(remote_user);
remote_host = strempty(remote_host);
seat = strempty(seat);
if (strchr(tty, ':')) {
/* A tty with a colon is usually an X11 display,
@ -318,8 +304,8 @@ _public_ PAM_EXTERN int pam_sm_open_session(
class = streq(type, "unspecified") ? "background" : "user";
remote = !isempty(remote_host) &&
!streq(remote_host, "localhost") &&
!streq(remote_host, "localhost.localdomain");
!streq_ptr(remote_host, "localhost") &&
!streq_ptr(remote_host, "localhost.localdomain");
/* Talk to logind over the message bus */
@ -332,7 +318,11 @@ _public_ PAM_EXTERN int pam_sm_open_session(
if (debug)
pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
"uid=%u pid=%u service=%s type=%s class=%s seat=%s vtnr=%u tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
uid, pid, service, type, class, seat, vtnr, tty, display, yes_no(remote), remote_user, remote_host);
pw->pw_uid, getpid(),
strempty(service),
type, class,
strempty(seat), vtnr, tty, strempty(display),
yes_no(remote), strempty(remote_user), strempty(remote_host));
r = sd_bus_call_method(bus,
"org.freedesktop.login1",
@ -342,18 +332,18 @@ _public_ PAM_EXTERN int pam_sm_open_session(
&error,
&reply,
"uussssussbssa(sv)",
uid,
pid,
service,
(uint32_t) pw->pw_uid,
(uint32_t) getpid(),
strempty(service),
type,
class,
seat,
strempty(seat),
vtnr,
tty,
display,
strempty(display),
remote,
remote_user,
remote_host,
strempty(remote_user),
strempty(remote_host),
0);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
@ -361,11 +351,12 @@ _public_ PAM_EXTERN int pam_sm_open_session(
}
r = sd_bus_message_read(reply,
"soshsub",
"soshusub",
&id,
&object_path,
&runtime_path,
&session_fd,
&original_uid,
&seat,
&vtnr,
&existing);
@ -376,8 +367,8 @@ _public_ PAM_EXTERN int pam_sm_open_session(
if (debug)
pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
"id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u",
id, object_path, runtime_path, session_fd, seat, vtnr);
"id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
if (r != PAM_SUCCESS) {
@ -385,10 +376,18 @@ _public_ PAM_EXTERN int pam_sm_open_session(
return r;
}
r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", runtime_path, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
return r;
if (original_uid == pw->pw_uid) {
/* Don't set $XDG_RUNTIME_DIR if the user we now
* authenticated for does not match the original user
* of the session. We do this in order not to result
* in privileged apps clobbering the runtime directory
* unnecessarily. */
r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", runtime_path, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
return r;
}
}
if (!isempty(seat)) {
@ -401,7 +400,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
if (vtnr > 0) {
char buf[DECIMAL_STR_MAX(vtnr)];
snprintf(buf, sizeof(buf), "%u", vtnr);
sprintf(buf, "%u", vtnr);
r = pam_misc_setenv(handle, "XDG_VTNR", buf, 0);
if (r != PAM_SUCCESS) {