From e9fbc77c8f6a396ce9432e3791710e30de6e570b Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sun, 13 Feb 2011 18:21:11 +0100 Subject: [PATCH] pam: introduce whitelist and blacklist user list feature This is useful to exclude root from the session logout killings or to limit killing to the selinux guest users. --- TODO | 2 - man/pam_systemd.xml | 50 ++++++++++++++---- src/pam-module.c | 125 ++++++++++++++++++++++++++++++++++++++------ 3 files changed, 147 insertions(+), 30 deletions(-) diff --git a/TODO b/TODO index 8660f16f9..4d5a14461 100644 --- a/TODO +++ b/TODO @@ -147,8 +147,6 @@ External: * patch kernel for cpu feature modalias for autoloading aes/kvm/... http://git.kernel.org/?p=linux/kernel/git/ak/linux-misc-2.6.git;a=shortlog;h=refs/heads/cpuid-match -* place /etc/inittab with explaining blurb. - * procps, psmisc, sysvinit-tools, hostname → util-linux-ng https://bugzilla.redhat.com/show_bug.cgi?id=614245 -- plymouth diff --git a/man/pam_systemd.xml b/man/pam_systemd.xml index 6fe698101..915e0b601 100644 --- a/man/pam_systemd.xml +++ b/man/pam_systemd.xml @@ -202,17 +202,43 @@ - + - Takes a boolean - argument. If true, all processes - created by the root user (UID 0) during his - session and from his session will be - kept around after he logged out. This - option allows cancelling the effect of - and - for the - root user. + Takes a comma + separated list of user names or + numeric user ids as argument. If this + option is used the effect of the + and + options + will apply only to the listed + users. If this option is not used the + option applies to all local + users. Note that + + takes precedence over this list and is + hence subtracted from the list + specified here. + + + + + + Takes a comma + separated list of user names or + numeric user ids as argument. Users + listed in this argument will not be + subject to the effect of + or + . Note + that that this option takes precedence + over + , and + hence whatever is listed for + + is guaranteed to never be killed by + this PAM module, independent of any + other configuration + setting. @@ -259,7 +285,9 @@ , , , - . + , + , + . diff --git a/src/pam-module.c b/src/pam-module.c index 117df0518..7f9158470 100644 --- a/src/pam-module.c +++ b/src/pam-module.c @@ -42,12 +42,14 @@ static int parse_argv(pam_handle_t *handle, bool *create_session, bool *kill_session, bool *kill_user, - bool *keep_root, char ***controllers, - char ***reset_controllers) { + char ***reset_controllers, + char ***kill_only_users, + char ***kill_exclude_users) { unsigned i; bool reset_controller_set = false; + bool kill_exclude_users_set = false; assert(argc >= 0); assert(argc == 0 || argv); @@ -82,15 +84,6 @@ static int parse_argv(pam_handle_t *handle, if (kill_user) *kill_user = k; - } else if (startswith(argv[i], "keep-root=")) { - if ((k = parse_boolean(argv[i] + 10)) < 0) { - pam_syslog(handle, LOG_ERR, "Failed to parse keep-root= argument."); - return k; - } - - if (keep_root) - *keep_root = k; - } else if (startswith(argv[i], "controllers=")) { if (controllers) { @@ -121,6 +114,36 @@ static int parse_argv(pam_handle_t *handle, reset_controller_set = true; + } else if (startswith(argv[i], "kill-only-users=")) { + + if (kill_only_users) { + char **l; + + if (!(l = strv_split(argv[i] + 16, ","))) { + pam_syslog(handle, LOG_ERR, "Out of memory."); + return -ENOMEM; + } + + strv_free(*kill_only_users); + *kill_only_users = l; + } + + } else if (startswith(argv[i], "kill-exclude-users=")) { + + if (kill_exclude_users) { + char **l; + + if (!(l = strv_split(argv[i] + 19, ","))) { + pam_syslog(handle, LOG_ERR, "Out of memory."); + return -ENOMEM; + } + + strv_free(*kill_exclude_users); + *kill_exclude_users = l; + } + + kill_exclude_users_set = true; + } else { pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]); return -EINVAL; @@ -147,6 +170,17 @@ static int parse_argv(pam_handle_t *handle, if (kill_session && *kill_session && kill_user) *kill_user = true; + if (!kill_exclude_users_set && kill_exclude_users) { + char **l; + + if (!(l = strv_new("root", NULL))) { + pam_syslog(handle, LOG_ERR, "Out of memory"); + return -ENOMEM; + } + + *kill_exclude_users = l; + } + return 0; } @@ -369,7 +403,11 @@ _public_ PAM_EXTERN int pam_sm_open_session( if (sd_booted() <= 0) return PAM_SUCCESS; - if (parse_argv(handle, argc, argv, &create_session, NULL, NULL, NULL, &controllers, &reset_controllers) < 0) + if (parse_argv(handle, + argc, argv, + &create_session, NULL, NULL, + &controllers, &reset_controllers, + NULL, NULL) < 0) return PAM_SESSION_ERR; if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS) @@ -500,6 +538,54 @@ static int session_remains(pam_handle_t *handle, const char *user_path) { return !!remains; } +static bool check_user_lists( + pam_handle_t *handle, + uid_t uid, + char **kill_only_users, + char **kill_exclude_users) { + + const char *name = NULL; + char **l; + + assert(handle); + + if (uid == 0) + name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */ + else { + struct passwd *pw; + + if ((pw = pam_modutil_getpwuid(handle, uid))) + name = pw->pw_name; + } + + STRV_FOREACH(l, kill_exclude_users) { + uint32_t id; + + if (safe_atou32(*l, &id) >= 0) + if ((uid_t) id == uid) + return false; + + if (name && streq(name, *l)) + return false; + } + + if (strv_isempty(kill_only_users)) + return true; + + STRV_FOREACH(l, kill_only_users) { + uint32_t id; + + if (safe_atou32(*l, &id) >= 0) + if ((uid_t) id == uid) + return true; + + if (name && streq(name, *l)) + return true; + } + + return false; +} + _public_ PAM_EXTERN int pam_sm_close_session( pam_handle_t *handle, int flags, @@ -508,13 +594,12 @@ _public_ PAM_EXTERN int pam_sm_close_session( const char *username = NULL; bool kill_session = false; bool kill_user = false; - bool keep_root = true; int lock_fd = -1, r; char *session_path = NULL, *nosession_path = NULL, *user_path = NULL; const char *id; struct passwd *pw; const void *created = NULL; - char **controllers = NULL, **c; + char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL; assert(handle); @@ -522,7 +607,11 @@ _public_ PAM_EXTERN int pam_sm_close_session( if (sd_booted() <= 0) return PAM_SUCCESS; - if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user, &keep_root, &controllers, NULL) < 0) + if (parse_argv(handle, + argc, argv, + NULL, &kill_session, &kill_user, + &controllers, NULL, + &kill_only_users, &kill_exclude_users) < 0) return PAM_SESSION_ERR; if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS) @@ -557,7 +646,7 @@ _public_ PAM_EXTERN int pam_sm_close_session( goto finish; } - if (kill_session && (pw->pw_uid != 0 || !keep_root)) { + if (kill_session && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) { pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username); /* Kill processes in session cgroup, and delete it */ @@ -591,7 +680,7 @@ _public_ PAM_EXTERN int pam_sm_close_session( pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r)); /* Kill user processes not attached to any session */ - if (kill_user && r == 0 && (pw->pw_uid != 0 || !keep_root)) { + if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) { /* Kill user cgroup */ if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0) @@ -635,6 +724,8 @@ finish: free(user_path); strv_free(controllers); + strv_free(kill_exclude_users); + strv_free(kill_only_users); return r; } -- 2.30.2