You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
systemd/SOURCES/0636-logind-validate-run-us...

90 lines
3.6 KiB

From c8b74ac5cf508c7bcec92d197880043af1d2bad7 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 9 Oct 2018 22:23:41 +0200
Subject: [PATCH] logind: validate /run/user/1000 before we set it
Let's be safe than sorry, in particular as logind doesn't set it up
anymore, but user-runtime-dir@.service does, and logind doesn't really
track success of that.
(cherry picked from commit b92171124819305985ed292cc472f6668a027425)
Related: #1642460
---
src/login/pam_systemd.c | 48 +++++++++++++++++++++++++++++++++++------
1 file changed, 41 insertions(+), 7 deletions(-)
diff --git a/src/login/pam_systemd.c b/src/login/pam_systemd.c
index b2b62540bb..64e1b4d1bf 100644
--- a/src/login/pam_systemd.c
+++ b/src/login/pam_systemd.c
@@ -319,6 +319,36 @@ static int update_environment(pam_handle_t *handle, const char *key, const char
return r;
}
+static bool validate_runtime_directory(pam_handle_t *handle, const char *path, uid_t uid) {
+ struct stat st;
+
+ assert(path);
+
+ /* Just 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. */
+
+ if (lstat(path, &st) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to stat() runtime directory '%s': %s", path, strerror(errno));
+ 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;
+}
+
_public_ PAM_EXTERN int pam_sm_open_session(
pam_handle_t *handle,
int flags,
@@ -377,10 +407,12 @@ _public_ PAM_EXTERN int pam_sm_open_session(
if (asprintf(&rt, "/run/user/"UID_FMT, pw->pw_uid) < 0)
return PAM_BUF_ERR;
- r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
- if (r != PAM_SUCCESS) {
- pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
- return r;
+ if (validate_runtime_directory(handle, rt, pw->pw_uid)) {
+ r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ return r;
+ }
}
r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
@@ -584,9 +616,11 @@ _public_ PAM_EXTERN int pam_sm_open_session(
* in privileged apps clobbering the runtime directory
* unnecessarily. */
- r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
- if (r != PAM_SUCCESS)
- return r;
+ if (validate_runtime_directory(handle, runtime_path, pw->pw_uid)) {
+ r = update_environment(handle, "XDG_RUNTIME_DIR", runtime_path);
+ if (r != PAM_SUCCESS)
+ return r;
+ }
r = export_legacy_dbus_address(handle, pw->pw_uid, runtime_path);
if (r != PAM_SUCCESS)