int
main(int argc, char **argv)
{
YK_KEY *yk = NULL;
bool error = true;
int exit_code = 0;
/* Options */
bool verbose = false;
char *action = ACTION_ADD_HMAC_CHALRESP;
int slot = 1;
ykp_errno = 0;
yk_errno = 0;
if (! parse_args(argc, argv,
&slot, &verbose,
&action,
&exit_code))
goto err;
exit_code = 1;
if (! strcmp(action, ACTION_ADD_HMAC_CHALRESP)) {
/*
* Set up challenge-response login authentication
*/
if (! init_yubikey (&yk))
goto err;
if (! check_firmware_version(yk, verbose, false))
goto err;
if (! do_add_hmac_chalresp (yk, slot, verbose, NULL, &exit_code))
goto err;
} else {
fprintf (stderr, "Unknown action '%s'\n", action);
goto err;
}
exit_code = 0;
error = false;
err:
if (error || exit_code != 0) {
report_yk_error ();
}
if (yk && !yk_close_key (yk)) {
report_yk_error ();
exit_code = 2;
}
if (!yk_release ()) {
report_yk_error ();
exit_code = 2;
}
exit (exit_code);
}
int
main(int argc, char **argv)
{
YK_KEY *yk = NULL;
bool error = true;
int exit_code = 0;
/* Options */
bool verbose = false;
char action[ACTION_MAX_LEN];
char *ptr = action;
char *output_dir = NULL;
int slot = 1;
unsigned int iterations = CR_DEFAULT_ITERATIONS;
ykp_errno = 0;
yk_errno = 0;
strcpy (action, ACTION_ADD_HMAC_CHALRESP);
if (! parse_args(argc, argv,
&slot, &verbose,
&ptr, &output_dir,
&iterations))
goto err;
exit_code = 1;
if (! strncmp(action, ACTION_ADD_HMAC_CHALRESP, ACTION_MAX_LEN)) {
/*
* Set up challenge-response login authentication
*/
if (! init_yubikey (&yk))
goto err;
if (! check_firmware_version(yk, verbose, false))
goto err;
if (! do_add_hmac_chalresp (yk, slot, verbose, output_dir, iterations, &exit_code))
goto err;
} else {
fprintf (stderr, "Unknown action '%s'\n", action);
goto err;
}
exit_code = 0;
error = false;
err:
if (error || exit_code != 0) {
report_yk_error ();
}
if (yk && !yk_close_key (yk)) {
report_yk_error ();
exit_code = 2;
}
if (!yk_release ()) {
report_yk_error ();
exit_code = 2;
}
exit (exit_code);
}
int main(int argc, char* argv[], char* envp[]){
// arguments sanity check
if (argc != 3 ||
strlen(argv[1]) < 1 ||
strlen(argv[2]) < 1)
{
printf("Usage %s [DEVICENAME] [NAME]\n", argv[0]);
return EXIT_FAILURE;
}
// check for root
if(geteuid())
{
printf("luks requires super user privileges.\n");
return EXIT_FAILURE;
}
YK_KEY *yk;
char *password;
unsigned int password_len;
unsigned int retry_counter = 0;
query_credentials:
// TODO: check if call on already initialized structure is safe
// initialize yubikey
while (!init_yubikey(&yk))
{
sleep(1);
}
// query password
password_len = -1;
password = getpass("Enter FDE password: "******"Could not unlock device with provided credentials, please try again\n");
// failed to unlock device, retry to query password
memset(password, 0, strlen(password));
if (retry_counter < MAX_RETRIES)
{
retry_counter++;
goto query_credentials;
}
}
memset(password, 0, strlen(password));
free(password);
return EXIT_SUCCESS;
}
static int
do_challenge_response(pam_handle_t *pamh, struct cfg *cfg, const char *username)
{
char *userfile = NULL, *tmpfile = NULL;
FILE *f = NULL;
unsigned char buf[CR_RESPONSE_SIZE + 16], response_hex[CR_RESPONSE_SIZE * 2 + 1];
int ret;
unsigned int flags = 0;
unsigned int response_len = 0;
unsigned int expect_bytes = 0;
YK_KEY *yk = NULL;
CR_STATE state;
int len;
char *errstr = NULL;
ret = PAM_AUTH_ERR;
flags |= YK_FLAG_MAYBLOCK;
if (! init_yubikey(&yk)) {
D(("Failed initializing YubiKey"));
goto out;
}
if (! check_firmware_version(yk, false, true)) {
D(("YubiKey does not support Challenge-Response (version 2.2 required)"));
goto out;
}
if (! get_user_challenge_file (yk, cfg->chalresp_path, username, &userfile)) {
D(("Failed getting user challenge file for user %s", username));
goto out;
}
DBG(("Loading challenge from file %s", userfile));
/* XXX should drop root privileges before opening file in user's home directory */
f = fopen(userfile, "r");
if (! load_chalresp_state(f, &state))
goto out;
if (fclose(f) < 0) {
f = NULL;
goto out;
}
if (! challenge_response(yk, state.slot, state.challenge, state.challenge_len,
true, flags, false,
buf, sizeof(buf), &response_len)) {
D(("Challenge-response FAILED"));
goto out;
}
/*
* Check YubiKey response against the expected response
*/
yubikey_hex_encode(response_hex, (char *)buf, response_len);
if (memcmp(buf, state.response, response_len) == 0) {
ret = PAM_SUCCESS;
} else {
D(("Unexpected C/R response : %s", response_hex));
goto out;
}
DBG(("Got the expected response, generating new challenge (%i bytes).", CR_CHALLENGE_SIZE));
errstr = "Error generating new challenge, please check syslog or contact your system administrator";
if (generate_random(state.challenge, sizeof(state.challenge))) {
D(("Failed generating new challenge!"));
goto out;
}
errstr = "Error communicating with Yubikey, please check syslog or contact your system administrator";
if (! challenge_response(yk, state.slot, state.challenge, CR_CHALLENGE_SIZE,
true, flags, false,
buf, sizeof(buf), &response_len)) {
D(("Second challenge-response FAILED"));
goto out;
}
/* the yk_* functions leave 'junk' in errno */
errno = 0;
/*
* Write the challenge and response we will expect the next time to the state file.
*/
if (response_len > sizeof(state.response)) {
D(("Got too long response ??? (%i/%i)", response_len, sizeof(state.response)));
goto out;
}
memcpy (state.response, buf, response_len);
state.response_len = response_len;
/* Write out the new file */
tmpfile = malloc(strlen(userfile) + 1 + 4);
if (! tmpfile)
goto out;
strcpy(tmpfile, userfile);
strcat(tmpfile, ".tmp");
f = fopen(tmpfile, "w");
if (! f)
goto out;
errstr = "Error updating Yubikey challenge, please check syslog or contact your system administrator";
if (! write_chalresp_state (f, &state))
goto out;
if (fclose(f) < 0) {
f = NULL;
goto out;
}
f = NULL;
if (rename(tmpfile, userfile) < 0) {
goto out;
}
DBG(("Challenge-response success!"));
errstr = NULL;
out:
if (yk_errno) {
if (yk_errno == YK_EUSBERR) {
syslog(LOG_ERR, "USB error: %s", yk_usb_strerror());
D(("USB error: %s", yk_usb_strerror()));
} else {
syslog(LOG_ERR, "Yubikey core error: %s", yk_strerror(yk_errno));
D(("Yubikey core error: %s", yk_strerror(yk_errno)));
}
}
if (errstr)
display_error(pamh, errstr);
if (errno) {
syslog(LOG_ERR, "Challenge response failed: %s", strerror(errno));
D(("Challenge response failed: %s", strerror(errno)));
}
if (yk)
yk_close_key(yk);
yk_release();
if (f)
fclose(f);
free(userfile);
free(tmpfile);
return ret;
}
static int
do_challenge_response(pam_handle_t *pamh, struct cfg *cfg, const char *username)
{
char *userfile = NULL, *tmpfile = NULL;
FILE *f = NULL;
char buf[CR_RESPONSE_SIZE + 16], response_hex[CR_RESPONSE_SIZE * 2 + 1];
int ret, fd;
unsigned int flags = 0;
unsigned int response_len = 0;
YK_KEY *yk = NULL;
CR_STATE state;
char *errstr = NULL;
struct passwd *p;
struct stat st;
ret = PAM_AUTH_ERR;
flags |= YK_FLAG_MAYBLOCK;
if (! init_yubikey(&yk)) {
D(("Failed initializing YubiKey"));
goto out;
}
if (! check_firmware_version(yk, false, true)) {
D(("YubiKey does not support Challenge-Response (version 2.2 required)"));
goto out;
}
if (! get_user_challenge_file (yk, cfg->chalresp_path, username, &userfile)) {
D(("Failed getting user challenge file for user %s", username));
goto out;
}
DBG(("Loading challenge from file %s", userfile));
p = getpwnam (username);
if (p == NULL) {
DBG (("getpwnam: %s", strerror(errno)));
goto out;
}
/* Drop privileges before opening user file. */
if (drop_privileges(p, pamh) < 0) {
D (("could not drop privileges"));
goto out;
}
fd = open(userfile, O_RDONLY, 0);
if (fd < 0) {
DBG (("Cannot open file: %s (%s)", userfile, strerror(errno)));
goto out;
}
if (fstat(fd, &st) < 0) {
DBG (("Cannot stat file: %s (%s)", userfile, strerror(errno)));
close(fd);
goto out;
}
if (!S_ISREG(st.st_mode)) {
DBG (("%s is not a regular file", userfile));
close(fd);
goto out;
}
f = fdopen(fd, "r");
if (f == NULL) {
DBG (("fdopen: %s", strerror(errno)));
close(fd);
goto out;
}
if (! load_chalresp_state(f, &state, cfg->debug))
goto out;
if (fclose(f) < 0) {
f = NULL;
goto out;
}
f = NULL;
if (restore_privileges(pamh) < 0) {
DBG (("could not restore privileges"));
goto out;
}
if (! challenge_response(yk, state.slot, state.challenge, state.challenge_len,
true, flags, false,
buf, sizeof(buf), &response_len)) {
D(("Challenge-response FAILED"));
goto out;
}
/*
* Check YubiKey response against the expected response
*/
yubikey_hex_encode(response_hex, buf, response_len);
if (memcmp(buf, state.response, response_len) == 0) {
ret = PAM_SUCCESS;
} else {
D(("Unexpected C/R response : %s", response_hex));
goto out;
}
DBG(("Got the expected response, generating new challenge (%i bytes).", CR_CHALLENGE_SIZE));
errstr = "Error generating new challenge, please check syslog or contact your system administrator";
if (generate_random(state.challenge, sizeof(state.challenge))) {
D(("Failed generating new challenge!"));
goto out;
}
errstr = "Error communicating with Yubikey, please check syslog or contact your system administrator";
if (! challenge_response(yk, state.slot, state.challenge, CR_CHALLENGE_SIZE,
true, flags, false,
buf, sizeof(buf), &response_len)) {
D(("Second challenge-response FAILED"));
goto out;
}
/* There is a bug that makes the YubiKey 2.2 send the same response for all challenges
unless HMAC_LT64 is set, check for that here */
if (memcmp(buf, state.response, response_len) == 0) {
errstr = "Same response for second challenge, YubiKey should be reconfigured with the option HMAC_LT64";
goto out;
}
/* the yk_* functions leave 'junk' in errno */
errno = 0;
/*
* Write the challenge and response we will expect the next time to the state file.
*/
if (response_len > sizeof(state.response)) {
D(("Got too long response ??? (%u/%lu)", response_len, (unsigned long) sizeof(state.response)));
goto out;
}
memcpy (state.response, buf, response_len);
state.response_len = response_len;
/* Drop privileges before creating new challenge file. */
if (drop_privileges(p, pamh) < 0) {
D (("could not drop privileges"));
goto out;
}
/* Write out the new file */
tmpfile = malloc(strlen(userfile) + 1 + 4);
if (! tmpfile)
goto out;
strcpy(tmpfile, userfile);
strcat(tmpfile, ".tmp");
fd = open(tmpfile, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
if (fd < 0) {
DBG (("Cannot open file: %s (%s)", tmpfile, strerror(errno)));
goto out;
}
f = fdopen(fd, "w");
if (! f) {
close(fd);
goto out;
}
errstr = "Error updating Yubikey challenge, please check syslog or contact your system administrator";
if (! write_chalresp_state (f, &state))
goto out;
if (fclose(f) < 0) {
f = NULL;
goto out;
}
f = NULL;
if (rename(tmpfile, userfile) < 0) {
goto out;
}
if (restore_privileges(pamh) < 0) {
DBG (("could not restore privileges"));
goto out;
}
DBG(("Challenge-response success!"));
errstr = NULL;
errno = 0;
out:
if (yk_errno) {
if (yk_errno == YK_EUSBERR) {
syslog(LOG_ERR, "USB error: %s", yk_usb_strerror());
D(("USB error: %s", yk_usb_strerror()));
} else {
syslog(LOG_ERR, "Yubikey core error: %s", yk_strerror(yk_errno));
D(("Yubikey core error: %s", yk_strerror(yk_errno)));
}
}
if (errstr)
display_error(pamh, errstr);
if (errno) {
syslog(LOG_ERR, "Challenge response failed: %s", strerror(errno));
D(("Challenge response failed: %s", strerror(errno)));
}
if (yk)
yk_close_key(yk);
yk_release();
if (f)
fclose(f);
free(userfile);
free(tmpfile);
return ret;
}
