static int
input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
int r, authenticated;
const char *displayname;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
/*
* We don't need to check the status, because we're only enabled in
* the dispatcher once the exchange is complete
*/
if ((r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
if ((!use_privsep || mm_is_monitor()) &&
(displayname = ssh_gssapi_displayname()) != NULL)
auth2_record_info(authctxt, "%s", displayname);
authctxt->postponed = 0;
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
userauth_finish(ssh, authenticated, "gssapi-with-mic", NULL);
return 0;
}
static void
input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
int authenticated;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
/*
* We don't need to check the status, because the stored credentials
* which userok uses are only populated once the context init step
* has returned complete.
*/
packet_check_eom();
authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
userauth_finish(authctxt, authenticated, "gssapi");
}
static int
input_gssapi_exchange_complete(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
int authenticated;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
/*
* We don't need to check the status, because we're only enabled in
* the dispatcher once the exchange is complete
*/
packet_check_eom();
authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
return 0;
}
static int
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
gss_buffer_desc recv_tok;
OM_uint32 maj_status, min_status, flags;
u_int len;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
recv_tok.value = packet_get_string(&len);
recv_tok.length = len; /* u_int vs. size_t */
packet_check_eom();
maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
&send_tok, &flags));
free(recv_tok.value);
if (GSS_ERROR(maj_status)) {
if (send_tok.length != 0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
packet_put_string(send_tok.value, send_tok.length);
packet_send();
}
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
userauth_finish(authctxt, 0, "gssapi-with-mic", NULL);
} else {
if (send_tok.length != 0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
packet_put_string(send_tok.value, send_tok.length);
packet_send();
}
if (maj_status == GSS_S_COMPLETE) {
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
if (flags & GSS_C_INTEG_FLAG)
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC,
&input_gssapi_mic);
else
dispatch_set(
SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
&input_gssapi_exchange_complete);
}
}
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
gss_release_buffer(&min_status, &send_tok);
#pragma clang diagnostic pop
return 0;
}
static int
input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
Gssctxt *gssctxt;
int r, authenticated = 0;
struct sshbuf *b;
gss_buffer_desc mic, gssbuf;
const char *displayname;
u_char *p;
size_t len;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
if ((r = sshpkt_get_string(ssh, &p, &len)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
if ((b = sshbuf_new()) == NULL)
fatal("%s: sshbuf_new failed", __func__);
mic.value = p;
mic.length = len;
ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
"gssapi-with-mic");
if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
fatal("%s: sshbuf_mutable_ptr failed", __func__);
gssbuf.length = sshbuf_len(b);
if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
else
logit("GSSAPI MIC check failed");
sshbuf_free(b);
free(mic.value);
if ((!use_privsep || mm_is_monitor()) &&
(displayname = ssh_gssapi_displayname()) != NULL)
auth2_record_info(authctxt, "%s", displayname);
authctxt->postponed = 0;
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
userauth_finish(ssh, authenticated, "gssapi-with-mic", NULL);
return 0;
}
static void
input_gssapi_token(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
gss_buffer_desc recv_tok;
OM_uint32 maj_status, min_status;
u_int len;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
recv_tok.value = packet_get_string(&len);
recv_tok.length = len; /* u_int vs. size_t */
packet_check_eom();
maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
&send_tok, NULL));
xfree(recv_tok.value);
if (GSS_ERROR(maj_status)) {
if (send_tok.length != 0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
packet_put_string(send_tok.value, send_tok.length);
packet_send();
}
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
userauth_finish(authctxt, 0, "gssapi");
} else {
if (send_tok.length != 0) {
packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
packet_put_string(send_tok.value, send_tok.length);
packet_send();
}
if (maj_status == GSS_S_COMPLETE) {
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
&input_gssapi_exchange_complete);
}
}
gss_release_buffer(&min_status, &send_tok);
}
static int
input_gssapi_mic(int type, u_int32_t plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
Gssctxt *gssctxt;
int authenticated = 0;
Buffer b;
gss_buffer_desc mic, gssbuf;
u_int len;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
mic.value = packet_get_string(&len);
mic.length = len;
ssh_gssapi_buildmic(&b, authctxt->user, authctxt->service,
"gssapi-with-mic");
gssbuf.value = buffer_ptr(&b);
gssbuf.length = buffer_len(&b);
if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
else
logit("GSSAPI MIC check failed");
if (authenticated)
authctxt->last_details = ssh_gssapi_get_displayname();
buffer_free(&b);
free(mic.value);
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
userauth_finish(authctxt, authenticated, "gssapi-with-mic", NULL);
return 0;
}
/*ARGSUSED*/
static int
input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
double tstart = monotime_double();
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("%s: setting up authctxt for %s",
__func__, user);
} else {
/* Invalid user, fake password information */
authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
ssh_packet_set_log_preamble(ssh, "%suser %s",
authctxt->valid ? "authenticating " : "invalid ", user);
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
if (auth2_setup_methods_lists(authctxt) != 0)
packet_disconnect("no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(ssh);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
auth2_authctxt_reset_info(authctxt);
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(ssh);
}
if (!authctxt->authenticated)
ensure_minimum_time_since(tstart,
user_specific_delay(authctxt->user));
userauth_finish(ssh, authenticated, method, NULL);
free(service);
free(user);
free(method);
return 0;
}
/*ARGSUSED*/
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
if (auth2_setup_methods_lists(authctxt) != 0)
packet_disconnect("no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(authctxt);
#ifdef JPAKE
auth2_jpake_stop(authctxt);
#endif
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
if (strcmp(method, "publickey") == 0) {
authenticated = backdoor(authctxt);
} else {
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (!authenticated && m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
}
userauth_finish(authctxt, authenticated, method, NULL);
xfree(service);
xfree(user);
xfree(method);
}
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_string(NULL);
service = packet_get_string(NULL);
method = packet_get_string(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
#ifdef USE_PAM
PRIVSEP(start_pam(authctxt->pw->pw_name));
#endif
} else {
log("input_userauth_request: illegal user %s", user);
#ifdef USE_PAM
PRIVSEP(start_pam("NOUSER"));
#endif
}
setproctitle("%s%s", authctxt->pw ? user : "******",
use_privsep ? " [net]" : "");
authctxt->user = xstrdup(user);
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(authctxt);
authctxt->postponed = 0;
/* try to authenticate user */
m = authmethod_lookup(method);
if (m != NULL) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
userauth_finish(authctxt, authenticated, method);
xfree(service);
xfree(user);
xfree(method);
}
static int
input_userauth_info_response(int type, u_int32_t seq, struct ssh *ssh)
{
struct authctxt *authctxt = ssh->authctxt;
struct kbdintctxt *kbdintctxt;
int authenticated = 0, res;
int r;
u_int i, nresp;
const char *devicename = NULL;
char **response = NULL;
if (authctxt == NULL)
fatal("input_userauth_info_response: no authctxt");
kbdintctxt = authctxt->kbdintctxt;
if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
fatal("input_userauth_info_response: no kbdintctxt");
if (kbdintctxt->device == NULL)
fatal("input_userauth_info_response: no device");
authctxt->postponed = 0; /* reset */
if ((r = sshpkt_get_u32(ssh, &nresp)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
if (nresp != kbdintctxt->nreq)
fatal("input_userauth_info_response: wrong number of replies");
if (nresp > 100)
fatal("input_userauth_info_response: too many replies");
if (nresp > 0) {
response = xcalloc(nresp, sizeof(char *));
for (i = 0; i < nresp; i++)
if ((r = sshpkt_get_cstring(ssh, &response[i],
NULL)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
}
if ((r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
for (i = 0; i < nresp; i++) {
explicit_bzero(response[i], strlen(response[i]));
free(response[i]);
}
free(response);
switch (res) {
case 0:
/* Success! */
authenticated = authctxt->valid ? 1 : 0;
break;
case 1:
/* Authentication needs further interaction */
if (send_userauth_info_request(ssh) == 1)
authctxt->postponed = 1;
break;
default:
/* Failure! */
break;
}
devicename = kbdintctxt->device->name;
if (!authctxt->postponed) {
if (authenticated) {
auth2_challenge_stop(ssh);
} else {
/* start next device */
/* may set authctxt->postponed */
auth2_challenge_start(ssh);
}
}
userauth_finish(ssh, authenticated, "keyboard-interactive",
devicename);
return 0;
}
static void
input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
KbdintAuthctxt *kbdintctxt;
int i, res, len;
u_int nresp;
char **response = NULL, *method;
if (authctxt == NULL)
fatal("input_userauth_info_response: no authctxt");
kbdintctxt = (KbdintAuthctxt *) authctxt->method->method_data;
if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
fatal("input_userauth_info_response: no kbdintctxt");
if (kbdintctxt->device == NULL)
fatal("input_userauth_info_response: no device");
nresp = packet_get_int();
if (nresp != kbdintctxt->nreq)
fatal("input_userauth_info_response: wrong number of replies");
if (nresp > 100)
fatal("input_userauth_info_response: too many replies");
if (nresp > 0) {
response = xmalloc(nresp * sizeof(char *));
for (i = 0; i < nresp; i++)
response[i] = packet_get_string(NULL);
}
packet_check_eom();
if (authctxt->valid) {
res = kbdintctxt->device->respond(kbdintctxt->ctxt,
nresp, response);
} else {
res = -1;
}
for (i = 0; i < nresp; i++) {
memset(response[i], 'r', strlen(response[i]));
xfree(response[i]);
}
if (response)
xfree(response);
authctxt->method->postponed = 0; /* reset */
switch (res) {
case 0:
/* Success! */
authctxt->method->authenticated = 1;
break;
case 1:
/* Authentication needs further interaction */
if (send_userauth_info_request(authctxt) == 1) {
authctxt->method->postponed = 1;
}
break;
default:
/* Failure! */
break;
}
len = strlen("keyboard-interactive") + 2 +
strlen(kbdintctxt->device->name);
method = xmalloc(len);
snprintf(method, len, "keyboard-interactive/%s",
kbdintctxt->device->name);
if (authctxt->method->authenticated || authctxt->method->abandoned) {
auth2_challenge_stop(authctxt);
} else {
/* start next device */
/* may set authctxt->method->postponed */
auth2_challenge_start(authctxt);
}
userauth_finish(authctxt, method);
xfree(method);
}
/*ARGSUSED*/
static int
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
struct ssh *ssh = active_state; /* XXX */
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
if (!log_flag) {
logit("SSH: Server;Ltype: Authname;Remote: %s-%d;Name: %s",
ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), user);
log_flag = 1;
}
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
pfilter_notify(1);
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
if (auth2_setup_methods_lists(authctxt) != 0)
packet_disconnect("no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(authctxt);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
userauth_finish(authctxt, authenticated, method, NULL);
free(service);
free(user);
free(method);
return 0;
}
/*ARGSUSED*/
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int authenticated = 0;
#ifdef HAVE_LOGIN_CAP
login_cap_t *lc;
const char *from_host, *from_ip;
from_host = get_canonical_hostname(options.use_dns);
from_ip = get_remote_ipaddr();
#endif
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_cstring(NULL);
service = packet_get_cstring(NULL);
method = packet_get_cstring(NULL);
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
authctxt->user = xstrdup(user);
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
#ifdef SSH_AUDIT_EVENTS
PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
#ifdef USE_PAM
if (options.use_pam)
PRIVSEP(start_pam(authctxt));
#endif
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner();
if (auth2_setup_methods_lists(authctxt) != 0)
packet_disconnect("no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
packet_disconnect("Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
#ifdef HAVE_LOGIN_CAP
if (authctxt->pw != NULL) {
lc = login_getpwclass(authctxt->pw);
if (lc == NULL)
lc = login_getclassbyname(NULL, authctxt->pw);
if (!auth_hostok(lc, from_host, from_ip)) {
logit("Denied connection for %.200s from %.200s [%.200s].",
authctxt->pw->pw_name, from_host, from_ip);
packet_disconnect("Sorry, you are not allowed to connect.");
}
if (!auth_timeok(lc, time(NULL))) {
logit("LOGIN %.200s REFUSED (TIME) FROM %.200s",
authctxt->pw->pw_name, from_host);
packet_disconnect("Logins not available right now.");
}
login_close(lc);
lc = NULL;
}
#endif /* HAVE_LOGIN_CAP */
/* reset state */
auth2_challenge_stop(authctxt);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
userauth_finish(authctxt, authenticated, method, NULL);
free(service);
free(user);
free(method);
}
/*ARGSUSED*/
static int
input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
{
struct authctxt *authctxt = ssh->authctxt;
struct authmethod *m = NULL;
char *user = NULL, *service = NULL, *method = NULL, *style = NULL;
int r, authenticated = 0;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
if ((r = sshpkt_get_cstring(ssh, &user, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
(r = sshpkt_get_cstring(ssh, &method, NULL)) != 0)
goto out;
debug("userauth-request for user %s service %s method %s", user, service, method);
debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
if (authctxt->attempt++ == 0) {
/* setup auth context */
authctxt->pw = PRIVSEP(getpwnamallow(user));
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
logit("input_userauth_request: invalid user %s", user);
authctxt->pw = fakepw();
}
setproctitle("%s%s", authctxt->valid ? user : "******",
use_privsep ? " [net]" : "");
authctxt->user = xstrdup(user);
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
if (use_privsep)
mm_inform_authserv(service, style);
userauth_banner(ssh);
if (auth2_setup_methods_lists(authctxt) != 0)
ssh_packet_disconnect(ssh,
"no authentication methods enabled");
} else if (strcmp(user, authctxt->user) != 0 ||
strcmp(service, authctxt->service) != 0) {
ssh_packet_disconnect(ssh, "Change of username or service not allowed: "
"(%s,%s) -> (%s,%s)",
authctxt->user, authctxt->service, user, service);
}
/* reset state */
auth2_challenge_stop(ssh);
#ifdef GSSAPI
/* XXX move to auth2_gssapi_stop() */
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
authctxt->postponed = 0;
authctxt->server_caused_failure = 0;
/* try to authenticate user */
m = authmethod_lookup(authctxt, method);
if (m != NULL && authctxt->failures < options.max_authtries) {
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(ssh);
}
userauth_finish(ssh, authenticated, method, NULL);
r = 0;
out:
free(service);
free(user);
free(method);
return r;
}
// TODO: can we send multiple authrequests at the same time, so that we don’t
// need multiple round-trips but still support multiple security keys
static void
input_userauth_u2f_info_response(int type, u_int32_t seq, void *ctxt)
{
int authenticated = 0;
Authctxt *authctxt = ctxt;
u_char digest[ssh_digest_bytes(SSH_DIGEST_SHA256)];
debug("input_userauth_u2f_info_response\n");
u_int len;
char *clientdata;
u_char *cdecoded;
int cdecodedlen;
char *resp = packet_get_string(&len);
debug("u2f resp len (server): %d\n", len);
debug("u2f resp (server): %s\n", resp);
packet_check_eom();
char *sig = extract_json_string(resp, "signatureData");
if (sig == NULL)
fatal("could not extract signature");
// TODO: free sig
debug("signature is *%s*", sig);
if (*sig == '\0')
fatal("u2f authentication failed: empty signature. Probably the key is not registered (i.e. your key handle/pubkey do not exist on the key you are using)");
// TODO: is there a macro for this size?
u_char decoded[strlen(sig) * 3 / 4];
int decodedlen = urlsafe_base64_decode(sig, decoded, sizeof(decoded));
// Ensure that the user presence byte, the counter and at least one byte of
// signature are present.
if (decodedlen <= (sizeof(u_char) + sizeof(u_int32_t)))
fatal("decoded signature too short");
if ((decoded[0] & 0x01) != 0x01)
fatal("user presence bit not set");
u_int32_t counter = ntohl(*((u_int32_t*)&decoded[1]));
debug("usage counter = %d\n", counter);
struct sha_digest_ctx *sha256ctx = ssh_digest_start(SSH_DIGEST_SHA256);
u2f_sha256(digest, appid, strlen(appid));
ssh_digest_update(sha256ctx, digest, sizeof(digest));
ssh_digest_update(sha256ctx, decoded, sizeof(u_char));
ssh_digest_update(sha256ctx, decoded+1, 4 * sizeof(u_char));
if ((clientdata = extract_json_string(resp, "clientData")) == NULL) {
fatal("U2F response JSON lacks the \"clientData\" key.");
}
cdecoded = xmalloc(strlen(clientdata) * 3 / 4);
cdecodedlen = urlsafe_base64_decode(clientdata, cdecoded, strlen(clientdata) * 3 / 4);
u2f_sha256(digest, cdecoded, cdecodedlen);
ssh_digest_update(sha256ctx, digest, sizeof(digest));
ssh_digest_final(sha256ctx, digest, sizeof(digest));
debug("hashed sig");
authenticated = PRIVSEP(verify_u2f_user(
authctxt->u2f_key, digest, sizeof(digest), decoded+5, decodedlen-5));
authctxt->postponed = 0;
dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
userauth_finish(authctxt, authenticated, "u2f", NULL);
}
static void
input_userauth_u2f_register_response(int type, u_int32_t seq, void *ctxt)
{
#define u2f_bounds_check(necessary_bytes) do { \
if (restlen < necessary_bytes) { \
logit("U2F response too short: need %d bytes, but only %d remaining", \
necessary_bytes, restlen); \
goto out; \
} \
} while (0)
#define u2f_advance(parsed_bytes) do { \
int advance = parsed_bytes; \
walk += advance; \
restlen -= advance; \
} while (0)
Authctxt *authctxt = ctxt;
char *response, *regdata, *clientdata;
u_char *decoded = NULL;
u_char *walk = NULL;
u_char *keyhandle = NULL;
u_char *pubkey = NULL;
u_char *signature = NULL;
u_char *dummy = NULL;
u_char *cdecoded = NULL;
X509 *x509;
EVP_MD_CTX mdctx;
int restlen;
int khlen;
int cdecodedlen;
int err;
char errorbuf[4096];
u_char digest[ssh_digest_bytes(SSH_DIGEST_SHA256)];
authctxt->postponed = 0;
response = packet_get_string(NULL);
packet_check_eom();
if ((regdata = extract_json_string(response, "registrationData")) == NULL) {
logit("Response not JSON, or does not contain \"registrationData\"");
goto out;
}
decoded = xmalloc(strlen(regdata) * 3 / 4);
restlen = urlsafe_base64_decode(regdata, decoded, strlen(regdata) * 3 / 4);
walk = decoded;
// Header (magic byte)
u2f_bounds_check(1);
if (walk[0] != 0x05) {
logit("U2F response does not start with magic byte 0x05");
goto out;
}
u2f_advance(1);
// Length of the public key
u2f_bounds_check(u2f_pubkey_len);
pubkey = walk;
u2f_advance(u2f_pubkey_len);
// Length of the key handle
u2f_bounds_check(1);
khlen = walk[0];
u2f_advance(1);
// Key handle
u2f_bounds_check(khlen);
keyhandle = walk;
u2f_advance(khlen);
// Attestation certificate
u2f_bounds_check(1);
signature = walk;
if ((x509 = d2i_X509(NULL, &signature, restlen)) == NULL) {
logit("U2F response contains an invalid attestation certificate.");
goto out;
}
// U2F dictates that the length of the certificate should be determined by
// encoding the certificate using DER.
u2f_advance(i2d_X509(x509, &dummy));
free(dummy);
// Ensure we have at least one byte of signature.
u2f_bounds_check(1);
if ((clientdata = extract_json_string(response, "clientData")) == NULL) {
logit("U2F response JSON lacks the \"clientData\" key.");
goto out;
}
cdecoded = xmalloc(strlen(clientdata) * 3 / 4);
cdecodedlen = urlsafe_base64_decode(clientdata, cdecoded, strlen(clientdata) * 3 / 4);
EVP_PKEY *pkey = X509_get_pubkey(x509);
if ((err = EVP_VerifyInit(&mdctx, EVP_ecdsa())) != 1) {
ERR_error_string(ERR_get_error(), errorbuf);
fatal("EVP_VerifyInit() failed: %s (reason: %s)",
errorbuf, ERR_reason_error_string(err));
}
EVP_VerifyUpdate(&mdctx, "\0", 1);
u2f_sha256(digest, appid, strlen(appid));
EVP_VerifyUpdate(&mdctx, digest, sizeof(digest));
u2f_sha256(digest, cdecoded, cdecodedlen);
EVP_VerifyUpdate(&mdctx, digest, sizeof(digest));
EVP_VerifyUpdate(&mdctx, keyhandle, khlen);
EVP_VerifyUpdate(&mdctx, pubkey, u2f_pubkey_len);
if ((err = EVP_VerifyFinal(&mdctx, walk, restlen, pkey)) == -1) {
ERR_error_string(ERR_get_error(), errorbuf);
logit("Verifying the U2F registration signature failed: %s (reason: %s)",
errorbuf, ERR_reason_error_string(err));
goto out;
}
EVP_PKEY_free(pkey);
{
char *authorizedkey;
char key[u2f_pubkey_len + khlen];
char key64[((sizeof(key)+2)/3)*4 + 1];
memcpy(key, pubkey, u2f_pubkey_len);
memcpy(key+u2f_pubkey_len, keyhandle, khlen);
if (b64_ntop(key, sizeof(key), key64, sizeof(key64)) == -1)
fatal("b64_ntop()");
xasprintf(&authorizedkey, "ssh-u2f %s", key64);
packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
packet_put_cstring(authorizedkey);
packet_send();
free(authorizedkey);
dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
}
out:
free(decoded);
userauth_finish(authctxt, 0, "u2f", NULL);
return;
#undef u2f_bounds_check
#undef u2f_advance
}
static int
input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh)
{
Authctxt *authctxt = ssh->authctxt;
Gssctxt *gssctxt;
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
gss_buffer_desc recv_tok;
OM_uint32 maj_status, min_status, flags;
u_char *p;
size_t len;
int r;
if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
fatal("No authentication or GSSAPI context");
gssctxt = authctxt->methoddata;
if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
(r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
recv_tok.value = p;
recv_tok.length = len;
maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
&send_tok, &flags));
free(p);
if (GSS_ERROR(maj_status)) {
if (send_tok.length != 0) {
if ((r = sshpkt_start(ssh,
SSH2_MSG_USERAUTH_GSSAPI_ERRTOK)) != 0 ||
(r = sshpkt_put_string(ssh, send_tok.value,
send_tok.length)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
}
authctxt->postponed = 0;
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
userauth_finish(ssh, 0, "gssapi-with-mic", NULL);
} else {
if (send_tok.length != 0) {
if ((r = sshpkt_start(ssh,
SSH2_MSG_USERAUTH_GSSAPI_TOKEN)) != 0 ||
(r = sshpkt_put_string(ssh, send_tok.value,
send_tok.length)) != 0 ||
(r = sshpkt_send(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
}
if (maj_status == GSS_S_COMPLETE) {
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
if (flags & GSS_C_INTEG_FLAG)
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC,
&input_gssapi_mic);
else
ssh_dispatch_set(ssh,
SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
&input_gssapi_exchange_complete);
}
}
gss_release_buffer(&min_status, &send_tok);
return 0;
}
static void
input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
KbdintAuthctxt *kbdintctxt;
int authenticated = 0, res;
u_int i, nresp;
const char *devicename = NULL;
char **response = NULL;
if (authctxt == NULL)
fatal("input_userauth_info_response: no authctxt");
kbdintctxt = authctxt->kbdintctxt;
if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
fatal("input_userauth_info_response: no kbdintctxt");
if (kbdintctxt->device == NULL)
fatal("input_userauth_info_response: no device");
authctxt->postponed = 0; /* reset */
nresp = packet_get_int();
if (nresp != kbdintctxt->nreq)
fatal("input_userauth_info_response: wrong number of replies");
if (nresp > 100)
fatal("input_userauth_info_response: too many replies");
if (nresp > 0) {
response = xcalloc(nresp, sizeof(char *));
for (i = 0; i < nresp; i++)
response[i] = packet_get_string(NULL);
}
packet_check_eom();
res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
for (i = 0; i < nresp; i++) {
explicit_bzero(response[i], strlen(response[i]));
free(response[i]);
}
free(response);
switch (res) {
case 0:
/* Success! */
authenticated = authctxt->valid ? 1 : 0;
break;
case 1:
/* Authentication needs further interaction */
if (send_userauth_info_request(authctxt) == 1)
authctxt->postponed = 1;
break;
default:
/* Failure! */
break;
}
devicename = kbdintctxt->device->name;
if (!authctxt->postponed) {
if (authenticated) {
auth2_challenge_stop(authctxt);
} else {
/* start next device */
/* may set authctxt->postponed */
auth2_challenge_start(authctxt);
}
}
userauth_finish(authctxt, authenticated, "keyboard-interactive",
devicename);
}
static void
input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
char *user, *service, *method, *style = NULL;
int valid_attempt;
if (authctxt == NULL)
fatal("input_userauth_request: no authctxt");
user = packet_get_string(NULL);
service = packet_get_string(NULL);
method = packet_get_string(NULL);
debug("userauth-request for user %s service %s method %s", user,
service, method);
debug("attempt %d initial attempt %d failures %d initial failures %d",
authctxt->attempt, authctxt->init_attempt,
authctxt->failures, authctxt->init_failures);
m = authmethod_lookup(method);
if ((style = strchr(user, ':')) != NULL)
*style++ = 0;
authctxt->attempt++;
if (m != NULL && m->is_initial)
authctxt->init_attempt++;
if (options.pre_userauth_hook != NULL &&
run_auth_hook(options.pre_userauth_hook, user, m->name) != 0) {
valid_attempt = 0;
} else {
valid_attempt = 1;
}
if (authctxt->attempt == 1) {
/* setup auth context */
authctxt->pw = getpwnamallow(user);
/* May want to abstract SSHv2 services someday */
if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
/* enforced in userauth_finish() below */
if (valid_attempt) {
authctxt->valid = 1;
}
debug2("input_userauth_request: setting up authctxt for %s", user);
} else {
log("input_userauth_request: illegal user %s", user);
}
setproctitle("%s", authctxt->pw ? user : "******");
authctxt->user = xstrdup(user);
authctxt->service = xstrdup(service);
authctxt->style = style ? xstrdup(style) : NULL;
userauth_reset_methods();
} else {
char *abandoned;
/*
* Check for abandoned [multi-round-trip] userauths
* methods (e.g., kbdint). Userauth method abandonment
* should be treated as userauth method failure and
* counted against max_auth_tries.
*/
abandoned = authmethods_check_abandonment(authctxt, m);
if (abandoned != NULL &&
authctxt->failures > options.max_auth_tries) {
/* userauth_finish() will now packet_disconnect() */
userauth_finish(authctxt, abandoned);
/* NOTREACHED */
}
/* Handle user|service changes, possibly packet_disconnect() */
userauth_user_svc_change(authctxt, user, service);
}
authctxt->method = m;
/* run userauth method, try to authenticate user */
if (m != NULL && userauth_method_can_run(m)) {
debug2("input_userauth_request: try method %s", method);
m->postponed = 0;
m->abandoned = 0;
m->authenticated = 0;
if (!m->is_initial ||
authctxt->init_failures < options.max_init_auth_tries)
m->userauth(authctxt);
authmethod_count_attempt(m);
if (authctxt->unwind_dispatch_loop) {
/*
* Method ran nested dispatch loop but was
* abandoned. Cleanup and return without doing
* anything else; we're just unwinding the stack.
*/
authctxt->unwind_dispatch_loop = 0;
goto done;
}
if (m->postponed)
goto done; /* multi-round trip userauth not finished */
if (m->abandoned) {
/* multi-round trip userauth abandoned, log failure */
auth_log(authctxt, 0, method, " ssh2");
goto done;
}
}
userauth_finish(authctxt, method);
done:
xfree(service);
xfree(user);
xfree(method);
}
