X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Fpam-module.c;h=93eb92956987709681f36b562da6257508527986;hp=1441987fdc39e7c944f167d383b2027448612d0b;hb=81481c99c2c60a72e4a3e189565f1e786bfbe588;hpb=c6c18be35bb1d300d0b62a568783cc1c477f7151 diff --git a/src/pam-module.c b/src/pam-module.c index 1441987fd..93eb92956 100644 --- a/src/pam-module.c +++ b/src/pam-module.c @@ -1,4 +1,4 @@ -/*-*- Mode: C; c-basic-offset: 8 -*-*/ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -31,20 +32,25 @@ #include #include -#include - #include "util.h" #include "cgroup-util.h" #include "macro.h" #include "sd-daemon.h" +#include "strv.h" static int parse_argv(pam_handle_t *handle, int argc, const char **argv, bool *create_session, bool *kill_session, - bool *kill_user) { + bool *kill_user, + char ***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); @@ -60,6 +66,7 @@ static int parse_argv(pam_handle_t *handle, if (create_session) *create_session = k; + } else if (startswith(argv[i], "kill-session=")) { if ((k = parse_boolean(argv[i] + 13)) < 0) { pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument."); @@ -77,15 +84,104 @@ static int parse_argv(pam_handle_t *handle, if (kill_user) *kill_user = k; + + } else if (startswith(argv[i], "controllers=")) { + + if (controllers) { + char **l; + + if (!(l = strv_split(argv[i] + 12, ","))) { + pam_syslog(handle, LOG_ERR, "Out of memory."); + return -ENOMEM; + } + + strv_free(*controllers); + *controllers = l; + } + + } else if (startswith(argv[i], "reset-controllers=")) { + + if (reset_controllers) { + char **l; + + if (!(l = strv_split(argv[i] + 18, ","))) { + pam_syslog(handle, LOG_ERR, "Out of memory."); + return -ENOMEM; + } + + strv_free(*reset_controllers); + *reset_controllers = l; + } + + 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; } } + if (!reset_controller_set && reset_controllers) { + char **l; + + if (!(l = strv_new("cpu", NULL))) { + pam_syslog(handle, LOG_ERR, "Out of memory"); + return -ENOMEM; + } + + *reset_controllers = l; + } + + if (controllers) + strv_remove(*controllers, "name=systemd"); + + if (reset_controllers) + strv_remove(*reset_controllers, "name=systemd"); + 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; } @@ -103,8 +199,10 @@ static int open_file_and_lock(const char *fn) { * as the filesystems in question should be local, and only * locally accessible, and most likely even tmpfs. */ - if (flock(fd, LOCK_EX) < 0) + if (flock(fd, LOCK_EX) < 0) { + close_nointr_nofail(fd); return -errno; + } return fd; } @@ -123,18 +221,19 @@ static uint64_t get_session_id(int *mode) { /* First attempt: let's use the session ID of the audit * system, if it is available. */ - if (read_one_line_file("/proc/self/sessionid", &s) >= 0) { - uint32_t u; - int r; + if (have_effective_cap(CAP_AUDIT_CONTROL) > 0) + if (read_one_line_file("/proc/self/sessionid", &s) >= 0) { + uint32_t u; + int r; - r = safe_atou32(s, &u); - free(s); + r = safe_atou32(s, &u); + free(s); - if (r >= 0 && u != (uint32_t) -1) { - *mode = SESSION_ID_AUDIT; - return (uint64_t) u; + if (r >= 0 && u != (uint32_t) -1 && u > 0) { + *mode = SESSION_ID_AUDIT; + return (uint64_t) u; + } } - } /* Second attempt, use our own counter. */ if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) { @@ -142,11 +241,10 @@ static uint64_t get_session_id(int *mode) { ssize_t r; /* We do a bit of endianess swapping here, just to be - * sure. /var should be machine specific anyway, and - * /var/run even mounted from tmpfs, so this - * byteswapping should really not be necessary. But - * then again, you never know, so let's avoid any - * risk. */ + * sure. /run should be machine specific anyway, and + * even mounted from tmpfs, so this byteswapping + * should really not be necessary. But then again, you + * never know, so let's avoid any risk. */ if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter)) counter = 1; @@ -176,58 +274,104 @@ static uint64_t get_session_id(int *mode) { /* Last attempt, pick a random value */ return (uint64_t) random_ull(); } + static int get_user_data( pam_handle_t *handle, const char **ret_username, struct passwd **ret_pw) { - const char *username; - struct passwd *pw; + const char *username = NULL; + struct passwd *pw = NULL; int r; + bool have_loginuid = false; + char *s; assert(handle); assert(ret_username); assert(ret_pw); - if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) { - pam_syslog(handle, LOG_ERR, "Failed to get user name."); - return r; + if (have_effective_cap(CAP_AUDIT_CONTROL) > 0) { + /* Only use audit login uid if we are executed with + * sufficient capabilities so that pam_loginuid could + * do its job. If we are lacking the CAP_AUDIT_CONTROL + * capabality we most likely are being run in a + * container and /proc/self/loginuid is useless since + * it probably contains a uid of the host system. */ + + if (read_one_line_file("/proc/self/loginuid", &s) >= 0) { + uint32_t u; + + r = safe_atou32(s, &u); + free(s); + + if (r >= 0 && u != (uint32_t) -1 && u > 0) { + have_loginuid = true; + pw = pam_modutil_getpwuid(handle, u); + } + } } - if (!username || !*username) { - pam_syslog(handle, LOG_ERR, "User name not valid."); - return PAM_AUTH_ERR; + if (!have_loginuid) { + if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) { + pam_syslog(handle, LOG_ERR, "Failed to get user name."); + return r; + } + + if (!username || !*username) { + pam_syslog(handle, LOG_ERR, "User name not valid."); + return PAM_AUTH_ERR; + } + + pw = pam_modutil_getpwnam(handle, username); } - if (!(pw = pam_modutil_getpwnam(handle, username))) { + if (!pw) { pam_syslog(handle, LOG_ERR, "Failed to get user data."); return PAM_USER_UNKNOWN; } *ret_pw = pw; - *ret_username = username; + *ret_username = username ? username : pw->pw_name; return PAM_SUCCESS; } -static int create_user_group(pam_handle_t *handle, const char *group, struct passwd *pw, bool attach) { +static int create_user_group( + pam_handle_t *handle, + const char *controller, + const char *group, + struct passwd *pw, + bool attach, + bool remember) { + int r; assert(handle); assert(group); if (attach) - r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, group, 0); + r = cg_create_and_attach(controller, group, 0); else - r = cg_create(SYSTEMD_CGROUP_CONTROLLER, group); + r = cg_create(controller, group); if (r < 0) { pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r)); return PAM_SESSION_ERR; } - if ((r = cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER, group, 0755, pw->pw_uid, pw->pw_gid)) < 0 || - (r = cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) { + if (r > 0 && remember) { + /* Remember that it was us who created this group, and + * that hence we need to remove it too. This is a + * protection against removing the cgroup when run + * recursively. */ + if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) { + pam_syslog(handle, LOG_ERR, "Failed to install created variable."); + return r; + } + } + + if ((r = cg_set_task_access(controller, group, 0644, pw->pw_uid, pw->pw_gid)) < 0 || + (r = cg_set_group_access(controller, group, 0755, pw->pw_uid, pw->pw_gid)) < 0) { pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r)); return PAM_SESSION_ERR; } @@ -235,6 +379,22 @@ static int create_user_group(pam_handle_t *handle, const char *group, struct pas return PAM_SUCCESS; } +static int reset_group( + pam_handle_t *handle, + const char *controller) { + + int r; + + assert(handle); + + if ((r = cg_attach(controller, "/", 0)) < 0) { + pam_syslog(handle, LOG_ERR, "Failed to reset cgroup for controller %s: %s", controller, strerror(-r)); + return PAM_SESSION_ERR; + } + + return PAM_SUCCESS; +} + _public_ PAM_EXTERN int pam_sm_open_session( pam_handle_t *handle, int flags, @@ -246,27 +406,33 @@ _public_ PAM_EXTERN int pam_sm_open_session( char *buf = NULL; int lock_fd = -1; bool create_session = true; + char **controllers = NULL, **reset_controllers = NULL, **c; + char *cgroup_user_tree = NULL; assert(handle); - pam_syslog(handle, LOG_INFO, "pam-systemd initializing"); - - if (parse_argv(handle, argc, argv, &create_session, NULL, NULL) < 0) - return PAM_SESSION_ERR; + /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */ /* Make this a NOP on non-systemd systems */ if (sd_booted() <= 0) return PAM_SUCCESS; - if ((r = cg_init()) < 0) { - pam_syslog(handle, LOG_ERR, "libcgroup initialization failed: %s", strerror(-r)); - r = PAM_SESSION_ERR; - goto finish; - } + 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) goto finish; + if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) { + pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r)); + r = PAM_SYSTEM_ERR; + goto finish; + } + if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) { pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m"); r = PAM_SYSTEM_ERR; @@ -279,7 +445,7 @@ _public_ PAM_EXTERN int pam_sm_open_session( goto finish; } - /* Create /var/run/$USER */ + /* Create /run/user/$USER */ free(buf); if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) { r = PAM_BUF_ERR; @@ -330,18 +496,28 @@ _public_ PAM_EXTERN int pam_sm_open_session( } } - r = asprintf(&buf, "/user/%s/%s", username, id); + r = asprintf(&buf, "%s/%s/%s", cgroup_user_tree, username, id); } else - r = asprintf(&buf, "/user/%s/no-session", username); + r = asprintf(&buf, "%s/%s/master", cgroup_user_tree, username); if (r < 0) { r = PAM_BUF_ERR; goto finish; } - if ((r = create_user_group(handle, buf, pw, true)) != PAM_SUCCESS) + pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf); + + if ((r = create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, buf, pw, true, true)) != PAM_SUCCESS) goto finish; + /* The additional controllers don't really matter, so we + * ignore the return value */ + STRV_FOREACH(c, controllers) + create_user_group(handle, *c, buf, pw, true, false); + + STRV_FOREACH(c, reset_controllers) + reset_group(handle, *c); + r = PAM_SUCCESS; finish: @@ -350,48 +526,86 @@ finish: if (lock_fd >= 0) close_nointr_nofail(lock_fd); + strv_free(controllers); + strv_free(reset_controllers); + + free(cgroup_user_tree); + return r; } static int session_remains(pam_handle_t *handle, const char *user_path) { - struct cgroup_file_info info; - int level = 0, r; - void *iterator = NULL; + int r; bool remains = false; + DIR *d; + char *subgroup; + + if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0) + return r; + + while ((r = cg_read_subgroup(d, &subgroup)) > 0) { + + remains = !streq(subgroup, "master"); + free(subgroup); + + if (remains) + break; + } + + closedir(d); + + if (r < 0) + return r; - zero(info); + return !!remains; +} + +static bool check_user_lists( + pam_handle_t *handle, + uid_t uid, + char **kill_only_users, + char **kill_exclude_users) { - r = cgroup_walk_tree_begin(SYSTEMD_CGROUP_CONTROLLER, user_path, 0, &iterator, &info, &level); - while (r == 0) { + const char *name = NULL; + char **l; - if (info.type != CGROUP_FILE_TYPE_DIR) - goto next; + assert(handle); - if (streq(info.path, "")) - goto next; + if (uid == 0) + name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */ + else { + struct passwd *pw; - if (streq(info.path, "no-session")) - goto next; + if ((pw = pam_modutil_getpwuid(handle, uid))) + name = pw->pw_name; + } - remains = true; - break; + STRV_FOREACH(l, kill_exclude_users) { + uint32_t id; - next: + if (safe_atou32(*l, &id) >= 0) + if ((uid_t) id == uid) + return false; - r = cgroup_walk_tree_next(0, &iterator, &info, level); + if (name && streq(name, *l)) + return false; } + if (strv_isempty(kill_only_users)) + return true; - if (remains) - r = 1; - else if (r == 0 || r == ECGEOF) - r = 0; - else - r = cg_translate_error(r, errno); + STRV_FOREACH(l, kill_only_users) { + uint32_t id; - assert_se(cgroup_walk_tree_end(&iterator) == 0); + if (safe_atou32(*l, &id) >= 0) + if ((uid_t) id == uid) + return true; - return r; + if (name && streq(name, *l)) + return true; + } + + return false; } _public_ PAM_EXTERN int pam_sm_close_session( @@ -406,60 +620,85 @@ _public_ PAM_EXTERN int pam_sm_close_session( char *session_path = NULL, *nosession_path = NULL, *user_path = NULL; const char *id; struct passwd *pw; + const void *created = NULL; + char **controllers = NULL, **c, **kill_only_users = NULL, **kill_exclude_users = NULL; + char *cgroup_user_tree = NULL; assert(handle); - if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user) < 0) - return PAM_SESSION_ERR; - /* Make this a NOP on non-systemd systems */ if (sd_booted() <= 0) return PAM_SUCCESS; + 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) goto finish; + if ((r = cg_get_user_path(&cgroup_user_tree)) < 0) { + pam_syslog(handle, LOG_ERR, "Failed to determine user cgroup tree: %s", strerror(-r)); + r = PAM_SYSTEM_ERR; + goto finish; + } + if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) { pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m"); r = PAM_SYSTEM_ERR; goto finish; } - if (asprintf(&user_path, "/user/%s", username) < 0) { + /* We are probably still in some session/user dir. Move ourselves out of the way as first step */ + if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, cgroup_user_tree, 0)) < 0) + pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r)); + + STRV_FOREACH(c, controllers) + if ((r = cg_attach(*c, cgroup_user_tree, 0)) < 0) + pam_syslog(handle, LOG_ERR, "Failed to move us away in %s hierarchy: %s", *c, strerror(-r)); + + if (asprintf(&user_path, "%s/%s", cgroup_user_tree, username) < 0) { r = PAM_BUF_ERR; goto finish; } - if ((id = pam_getenv(handle, "XDG_SESSION_ID"))) { + pam_get_data(handle, "systemd.created", &created); + + if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) { - if (asprintf(&session_path, "/user/%s/%s", username, id) < 0 || - asprintf(&nosession_path, "/user/%s/no-session", username) < 0) { + if (asprintf(&session_path, "%s/%s/%s", cgroup_user_tree, username, id) < 0 || + asprintf(&nosession_path, "%s/%s/master", cgroup_user_tree, username) < 0) { r = PAM_BUF_ERR; goto finish; } - if (kill_session) { - /* Kill processes in session cgroup */ - if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path)) < 0) + 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 */ + if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0) pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r)); + } else { + pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path); - } else { - /* Migrate processes from session to - * no-session cgroup. First, try to create the - * no-session group in case it doesn't exist - * yet. */ - create_user_group(handle, nosession_path, pw, 0); + /* Migrate processes from session to user + * cgroup. First, try to create the user group + * in case it doesn't exist yet. Also, delete + * the session group. */ + create_user_group(handle, SYSTEMD_CGROUP_CONTROLLER, nosession_path, pw, false, false); - if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false)) < 0) + if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 0) pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r)); } - /* Delete session cgroup */ - if (r < 0) - pam_syslog(handle, LOG_INFO, "Couldn't empty session cgroup, not deleting."); - else { - if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, session_path)) < 0) - pam_syslog(handle, LOG_ERR, "Failed to delete session cgroup: %s", strerror(-r)); + STRV_FOREACH(c, controllers) { + create_user_group(handle, *c, nosession_path, pw, false, false); + + if ((r = cg_migrate_recursive(*c, session_path, nosession_path, false, true)) < 0) + pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup in hierarchy %s: %s", *c, strerror(-r)); } } @@ -470,35 +709,39 @@ _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) { + if (kill_user && r == 0 && check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users)) { - /* Kill no-session cgroup */ - if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0) + /* Kill user cgroup */ + if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0) pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r)); } else { if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 0) pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r)); - /* If we managed to kill somebody, don't cleanup the cgroup. */ - if (r == 0) + /* Remove user cgroup */ + if (r > 0) { + if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0) + pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r)); + + /* If we managed to find somebody, don't cleanup the cgroup. */ + } else if (r == 0) r = -EBUSY; } + STRV_FOREACH(c, controllers) + cg_trim(*c, user_path, true); + if (r >= 0) { const char *runtime_dir; - /* Remove user cgroup */ - if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0) - pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r)); - - /* This will migrate us to the /user cgroup. */ - if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR"))) if ((r = rm_rf(runtime_dir, false, true)) < 0) pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r)); } + /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */ + r = PAM_SUCCESS; finish: @@ -509,5 +752,11 @@ finish: free(nosession_path); free(user_path); + strv_free(controllers); + strv_free(kill_exclude_users); + strv_free(kill_only_users); + + free(cgroup_user_tree); + return r; }