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#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <signal.h>
#include <unistd.h>
#include <syslog.h>
#include "openvpn-plugin.h"
#ifndef USE_PERL
#define INTERPRETER "python"
#define DUO_SCRIPT_PATH PREFIX "/duo_openvpn.py"
#else
#define INTERPRETER "perl"
#define DUO_SCRIPT_PATH PREFIX "/duo_openvpn.pl"
#endif
struct context {
char *ikey;
char *skey;
char *host;
char *proxy_host;
char *proxy_port;
};
static const char *
get_env(const char *name, const char *envp[])
{
int i, namelen;
const char *cp;
if (envp) {
namelen = strlen(name);
for (i = 0; envp[i]; ++i) {
if (!strncmp(envp[i], name, namelen)) {
cp = envp[i] + namelen;
if (*cp == '=') {
return cp + 1;
}
}
}
}
return NULL;
}
static int
auth_user_pass_verify(struct context *ctx, const char *args[], const char *envp[])
{
int pid;
const char *control, *username, *password, *ipaddr;
char *argv[] = { INTERPRETER, DUO_SCRIPT_PATH, NULL };
control = get_env("auth_control_file", envp);
username = get_env("common_name", envp);
password = get_env("password", envp);
ipaddr = get_env("untrusted_ip", envp);
if (!control || !username || !password || !ipaddr) {
return OPENVPN_PLUGIN_FUNC_ERROR;
}
pid = fork();
if (pid < 0) {
return OPENVPN_PLUGIN_FUNC_ERROR;
}
if (pid > 0) {
int status;
/* openvpn process forked ok, wait for first child to exit and return its status */
pid = waitpid(pid, &status, 0);
if (pid < 0) {
return OPENVPN_PLUGIN_FUNC_ERROR;
}
if (WIFEXITED(status)) {
return WEXITSTATUS(status);
}
return OPENVPN_PLUGIN_FUNC_ERROR;
}
pid = fork();
if (pid < 0) {
exit(OPENVPN_PLUGIN_FUNC_ERROR);
}
if (pid > 0) {
/* first child forked ok, pass deferred return up to parent openvpn process */
exit(OPENVPN_PLUGIN_FUNC_DEFERRED);
}
/* second child daemonizes so PID 1 can reap */
umask(0);
setsid();
chdir("/");
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
if (ctx->ikey && ctx->skey && ctx->host) {
setenv("ikey", ctx->ikey, 1);
setenv("skey", ctx->skey, 1);
setenv("host", ctx->host, 1);
if (ctx->proxy_host) {
setenv("proxy_host", ctx->proxy_host, 1);
}
else {
unsetenv("proxy_host");
}
if (ctx->proxy_port) {
setenv("proxy_port", ctx->proxy_port, 1);
}
else {
unsetenv("proxy_port");
}
}
setenv("control", control, 1);
setenv("username", username, 1);
setenv("password", password, 1);
setenv("ipaddr", ipaddr, 1);
execvp(argv[0], argv);
exit(1);
}
OPENVPN_EXPORT int
openvpn_plugin_func_v2(openvpn_plugin_handle_t handle, const int type, const char *argv[], const char *envp[], void *per_client_context, struct openvpn_plugin_string_list **return_list)
{
struct context *ctx = (struct context *) handle;
if (type == OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY) {
return auth_user_pass_verify(ctx, argv, envp);
} else {
return OPENVPN_PLUGIN_FUNC_ERROR;
}
}
OPENVPN_EXPORT openvpn_plugin_handle_t
openvpn_plugin_open_v2(unsigned int *type_mask, const char *argv[], const char *envp[], struct openvpn_plugin_string_list **return_list)
{
struct context *ctx;
ctx = (struct context *) calloc(1, sizeof(struct context));
if (argv[1] && argv[2] && argv[3]) {
ctx->ikey = strdup(argv[1]);
ctx->skey = strdup(argv[2]);
ctx->host = strdup(argv[3]);
}
/* Passing proxy_host even if proxy_port is not present
* generates a more informative log message.
*/
if (argv[4]) {
ctx->proxy_host = strdup(argv[4]);
if (argv[5]) {
ctx->proxy_port = strdup(argv[5]);
}
else {
ctx->proxy_port = NULL;
}
}
else {
ctx->proxy_host = NULL;
ctx->proxy_port = NULL;
}
*type_mask = OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY);
return (openvpn_plugin_handle_t) ctx;
}
OPENVPN_EXPORT void
openvpn_plugin_close_v1(openvpn_plugin_handle_t handle)
{
struct context *ctx = (struct context *) handle;
free(ctx->ikey);
free(ctx->skey);
free(ctx->host);
if (ctx->proxy_host) {
free(ctx->proxy_host);
}
if (ctx->proxy_port) {
free(ctx->proxy_port);
}
free(ctx);
}
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