From 4ae930d9ddb8d2f806f89068142f4e7cd4df85e6 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 26 Nov 2013 05:05:00 +0100
Subject: [PATCH] pam_systemd: do not set XDG_RUNTIME_DIR if the session's
original user is not the same as the newly logged in one
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.
(cherry picked from commit baae0358f349870544884e405e82e4be7d8add9f)
Conflicts:
src/login/logind-dbus.c
src/login/logind-session-dbus.c
src/login/pam-module.c
Note: Backported by Dr. Werner Fink <werner@suse.de>
---
src/login/logind-dbus.c | 1 +
src/login/logind-session-dbus.c | 1 +
src/login/pam-module.c | 67 ++++++++++++++++++++++-------------------
3 files changed, 38 insertions(+), 31 deletions(-)
diff --git a/src/login/logind-dbus.c b/src/login/logind-dbus.c
index 583d62e..6f3e442 100644
--- a/src/login/logind-dbus.c
+++ b/src/login/logind-dbus.c
@@ -523,6 +523,7 @@ static int bus_manager_create_session(Manager *m, DBusMessage *message) {
DBUS_TYPE_OBJECT_PATH, &path,
DBUS_TYPE_STRING, &session->user->runtime_path,
DBUS_TYPE_UNIX_FD, &fifo_fd,
+ DBUS_TYPE_UINT32, &session->user->uid,
DBUS_TYPE_STRING, &cseat,
DBUS_TYPE_UINT32, &vtnr,
DBUS_TYPE_BOOLEAN, &exists,
diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c
index be4e01c..86b0746 100644
--- a/src/login/logind-session-dbus.c
+++ b/src/login/logind-session-dbus.c
@@ -755,6 +755,7 @@ int session_send_create_reply(Session *s, DBusError *error) {
DBUS_TYPE_OBJECT_PATH, &path,
DBUS_TYPE_STRING, &s->user->runtime_path,
DBUS_TYPE_UNIX_FD, &fifo_fd,
+ DBUS_TYPE_UINT32, &s->user->uid,
DBUS_TYPE_STRING, &cseat,
DBUS_TYPE_UINT32, &vtnr,
DBUS_TYPE_BOOLEAN, &exists,
diff --git a/src/login/pam-module.c b/src/login/pam-module.c
index aa09ec1..4d6b052 100644
--- a/src/login/pam-module.c
+++ b/src/login/pam-module.c
@@ -86,31 +86,24 @@ 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;
- }
+ r = pam_get_user(handle, &username, NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user name.");
+ return r;
+ }
- pw = pam_modutil_getpwnam(handle, username);
+ 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;
@@ -123,16 +116,14 @@ 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);
@@ -194,14 +185,12 @@ _public_ PAM_EXTERN int pam_sm_open_session(
dbus_bool_t remote, existing;
int r;
uint32_t vtnr = 0;
+ uid_t original_uid;
assert(handle);
dbus_error_init(&error);
- if (debug)
- pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
-
/* Make this a NOP on non-logind systems */
if (!logind_running())
return PAM_SUCCESS;
@@ -214,6 +203,9 @@ _public_ PAM_EXTERN int pam_sm_open_session(
goto finish;
}
+ if (debug)
+ pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
+
r = get_user_data(handle, &username, &pw);
if (r != PAM_SUCCESS)
goto finish;
@@ -381,7 +373,11 @@ _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, pid,
+ strempty(service),
+ type, class,
+ seat, vtnr, tty, display,
+ yes_no(remote), remote_user, remote_host);
reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
if (!reply) {
@@ -395,6 +391,7 @@ _public_ PAM_EXTERN int pam_sm_open_session(
DBUS_TYPE_OBJECT_PATH, &object_path,
DBUS_TYPE_STRING, &runtime_path,
DBUS_TYPE_UNIX_FD, &session_fd,
+ DBUS_TYPE_UINT32, &original_uid,
DBUS_TYPE_STRING, &seat,
DBUS_TYPE_UINT32, &vtnr,
DBUS_TYPE_BOOLEAN, &existing,
@@ -406,8 +403,8 @@ _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) {
@@ -415,10 +412,18 @@ _public_ PAM_EXTERN int pam_sm_open_session(
goto finish;
}
- 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.");
- goto finish;
+ 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.");
+ goto finish;
+ }
}
if (!isempty(seat)) {