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#include <librc.h>
#include <pwd.h>
#include <security/pam_appl.h>
#include <security/pam_ext.h>
#include <security/pam_modules.h>
#include <stdbool.h>
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include <string.h>
#include "einfo.h"
#include "queue.h"
static void load_envs_from_file(const char *path, RC_STRINGLIST *out) {
FILE *fp = NULL;
char *line = NULL;
size_t n = 0;
char *p = NULL;
fp = fopen(path, "r");
if (!fp) {
return;
}
while (getline(&line, &n, fp) != -1) {
if ((p = strchr(line, '\n'))) {
*p = '\0';
};
rc_stringlist_addu(out, line);
}
fclose(fp);
}
static RC_STRINGLIST *load_dir(const char *dir) {
RC_STRINGLIST *list = rc_stringlist_new();
DIR *dp = NULL;
struct dirent *d = NULL;
char *path;
if ((dp = opendir(dir)) != NULL) {
while ((d = readdir(dp)) != NULL) {
xasprintf(&path, "%s/%s", dir, d->d_name);
load_envs_from_file(path, list);
}
}
closedir(dp);
return list;
}
static void set_user_env(pam_handle_t *pamh) {
RC_STRINGLIST *allowed_env = NULL;
RC_STRINGLIST *user_env = NULL;
RC_STRING *env;
RC_STRING *uenv;
char *p;
char *user_env_path;
pam_syslog(pamh, LOG_INFO, "Loading allowed envs in %s", RC_USER_ENV_WHITELIST_D);
allowed_env = load_dir(RC_USER_ENV_WHITELIST_D);
pam_syslog(pamh, LOG_INFO, "Loading allowed envs in %s", RC_USER_ENV_WHITELIST);
load_envs_from_file(RC_USER_ENV_WHITELIST, allowed_env);
xasprintf(&user_env_path, "%s/openrc/env", pam_getenv(pamh, "XDG_RUNTIME_DIR"));
pam_syslog(pamh, LOG_INFO, "Loading user envs in %s", user_env_path);
user_env = load_dir(user_env_path);
TAILQ_FOREACH(env, allowed_env, entries) {
pam_syslog(pamh, LOG_INFO, "allowed env %s", env->value);
TAILQ_FOREACH(uenv, user_env, entries) {
p = strchr(uenv->value, '=');
if (p) {
*p = '\0';
if (strcmp(env->value, uenv->value) == 0) {
*p = '=';
pam_syslog(pamh, LOG_INFO, "Exporting: %s", uenv->value);
pam_putenv(pamh, uenv->value);
} else {
*p = '=';
}
}
}
}
pam_syslog(pamh, LOG_INFO, "Finished loading user environment");
rc_stringlist_free(allowed_env);
rc_stringlist_free(user_env);
free(user_env_path);
}
static int
exec_user_cmd(struct passwd *pw, char *cmd, char **envlist)
{
int retval;
const char *shellname = basename_c(pw->pw_shell);
switch (fork()) {
case 0:
setgid(pw->pw_gid);
setuid(pw->pw_uid);
execle(pw->pw_shell, shellname, "-c", cmd, NULL, envlist);
return -1;
break;
case -1:
return -1;
break;
}
wait(&retval);
return retval;
}
static char *create_xdg_runtime_dir(struct passwd *pw) {
char *path = NULL;
char *openrc_path = NULL;
if (mkdir("/run/user", 0755) != 0 && errno != EEXIST)
return NULL;
xasprintf(&path, "/run/user/%d/", pw->pw_uid);
if (mkdir(path, 0700) != 0 && errno != EEXIST) {
free(path);
return NULL;
}
if (chown(path, pw->pw_uid, pw->pw_gid) != 0) {
free(path);
return NULL;
}
xasprintf(&openrc_path, "%s/%s", path, "openrc");
if (mkdir(openrc_path, 0700) != 0 && errno != EEXIST) {
free(openrc_path);
free(path);
return NULL;
}
if (chown(openrc_path, pw->pw_uid, pw->pw_gid) != 0) {
free(openrc_path);
free(path);
return NULL;
}
return path;
}
static bool exec_openrc(pam_handle_t *pamh, const char *runlevel, bool lock) {
char *cmd = NULL;
const char *username;
struct passwd *pw = NULL;
char *xdg_runtime_dir;
char *xdg_runtime_dir_env;
char **envlist;
char **env;
if (pam_get_user(pamh, &username, "username:") != PAM_SUCCESS)
return false;
pw = getpwnam(username);
if (!pw)
return false;
/* XDG_RUNTIME_DIR is needed in so many places, that if it's not defined
* we're defining it on the standard location. */
if (pam_getenv(pamh, "XDG_RUNTIME_DIR") == NULL) {
xdg_runtime_dir = create_xdg_runtime_dir(pw);
if (!xdg_runtime_dir) {
return false;
}
xasprintf(&xdg_runtime_dir_env, "XDG_RUNTIME_DIR=%s", xdg_runtime_dir);
pam_putenv(pamh, xdg_runtime_dir_env);
pam_syslog(pamh, LOG_INFO, "exporting: %s", xdg_runtime_dir_env);
free(xdg_runtime_dir);
free(xdg_runtime_dir_env);
}
envlist = pam_getenvlist(pamh);
xasprintf(&cmd, "openrc --user %s %s", lock ? "--lock" : "--unlock", runlevel);
pam_syslog(pamh, LOG_INFO, "Executing %s for user %s", cmd, username);
exec_user_cmd(pw, cmd, envlist);
set_user_env(pamh);
for (env = envlist; *env; env++)
free(*env);
free(envlist);
free(cmd);
return true;
}
PAM_EXTERN int pam_sm_open_session(pam_handle_t *pamh, int flags, int argc, const char **argv) {
const char *runlevel = argc > 0 ? runlevel = argv[0] : "default";
(void)flags;
pam_syslog(pamh, LOG_INFO, "Opening openrc session");
if (exec_openrc(pamh, runlevel, true)) {
pam_syslog(pamh, LOG_INFO, "Openrc session opened");
return PAM_SUCCESS;
} else {
pam_syslog(pamh, LOG_ERR, "Failed to open session");
return PAM_SESSION_ERR;
}
}
PAM_EXTERN int pam_sm_close_session(pam_handle_t *pamh, int flags, int argc, const char **argv) {
const char *runlevel = argc > 1 ? argv[1] : "none";
(void)flags;
pam_syslog(pamh, LOG_INFO, "Closing openrc session");
if (exec_openrc(pamh, runlevel, false)) {
pam_syslog(pamh, LOG_INFO, "Openrc session closed");
return PAM_SUCCESS;
} else {
pam_syslog(pamh, LOG_ERR, "Failed to close session");
return PAM_SESSION_ERR;
}
}
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