308 lines
8.3 KiB
C
308 lines
8.3 KiB
C
/*
|
|
* Copyright (c) 2000 Markus Friedl. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "includes.h"
|
|
RCSID("$OpenBSD: auth2.c,v 1.96 2003/02/06 21:22:43 markus Exp $");
|
|
|
|
#include "ssh2.h"
|
|
#include "xmalloc.h"
|
|
#include "packet.h"
|
|
#include "log.h"
|
|
#include "servconf.h"
|
|
#include "compat.h"
|
|
#include "auth.h"
|
|
#include "dispatch.h"
|
|
#include "pathnames.h"
|
|
#include "monitor_wrap.h"
|
|
|
|
/* import */
|
|
extern ServerOptions options;
|
|
extern u_char *session_id2;
|
|
extern int session_id2_len;
|
|
|
|
Authctxt *x_authctxt = NULL;
|
|
|
|
/* methods */
|
|
|
|
extern Authmethod method_none;
|
|
extern Authmethod method_pubkey;
|
|
extern Authmethod method_passwd;
|
|
extern Authmethod method_kbdint;
|
|
extern Authmethod method_hostbased;
|
|
|
|
Authmethod *authmethods[] = {
|
|
&method_none,
|
|
&method_pubkey,
|
|
&method_passwd,
|
|
&method_kbdint,
|
|
&method_hostbased,
|
|
NULL
|
|
};
|
|
|
|
/* protocol */
|
|
|
|
static void input_service_request(int, u_int32_t, void *);
|
|
static void input_userauth_request(int, u_int32_t, void *);
|
|
|
|
/* helper */
|
|
static Authmethod *authmethod_lookup(const char *);
|
|
static char *authmethods_get(void);
|
|
int user_key_allowed(struct passwd *, Key *);
|
|
int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
|
|
|
|
/*
|
|
* loop until authctxt->success == TRUE
|
|
*/
|
|
|
|
Authctxt *
|
|
do_authentication2(void)
|
|
{
|
|
Authctxt *authctxt = authctxt_new();
|
|
|
|
x_authctxt = authctxt; /*XXX*/
|
|
|
|
/* challenge-response is implemented via keyboard interactive */
|
|
if (options.challenge_response_authentication)
|
|
options.kbd_interactive_authentication = 1;
|
|
if (options.pam_authentication_via_kbd_int)
|
|
options.kbd_interactive_authentication = 1;
|
|
if (use_privsep)
|
|
options.pam_authentication_via_kbd_int = 0;
|
|
|
|
dispatch_init(&dispatch_protocol_error);
|
|
dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
|
|
dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
|
|
|
|
return (authctxt);
|
|
}
|
|
|
|
static void
|
|
input_service_request(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Authctxt *authctxt = ctxt;
|
|
u_int len;
|
|
int acceptit = 0;
|
|
char *service = packet_get_string(&len);
|
|
packet_check_eom();
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_service_request: no authctxt");
|
|
|
|
if (strcmp(service, "ssh-userauth") == 0) {
|
|
if (!authctxt->success) {
|
|
acceptit = 1;
|
|
/* now we can handle user-auth requests */
|
|
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
|
|
}
|
|
}
|
|
/* XXX all other service requests are denied */
|
|
|
|
if (acceptit) {
|
|
packet_start(SSH2_MSG_SERVICE_ACCEPT);
|
|
packet_put_cstring(service);
|
|
packet_send();
|
|
packet_write_wait();
|
|
} else {
|
|
debug("bad service request %s", service);
|
|
packet_disconnect("bad service request %s", service);
|
|
}
|
|
xfree(service);
|
|
}
|
|
|
|
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 : "unknown",
|
|
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);
|
|
}
|
|
|
|
void
|
|
userauth_finish(Authctxt *authctxt, int authenticated, char *method)
|
|
{
|
|
char *methods;
|
|
|
|
if (!authctxt->valid && authenticated)
|
|
fatal("INTERNAL ERROR: authenticated invalid user %s",
|
|
authctxt->user);
|
|
|
|
/* Special handling for root */
|
|
if (authenticated && authctxt->pw->pw_uid == 0 &&
|
|
!auth_root_allowed(method))
|
|
authenticated = 0;
|
|
|
|
#ifdef USE_PAM
|
|
if (!use_privsep && authenticated && authctxt->user &&
|
|
!do_pam_account(authctxt->user, NULL))
|
|
authenticated = 0;
|
|
#endif /* USE_PAM */
|
|
|
|
#ifdef _UNICOS
|
|
if (authenticated && cray_access_denied(authctxt->user)) {
|
|
authenticated = 0;
|
|
fatal("Access denied for user %s.",authctxt->user);
|
|
}
|
|
#endif /* _UNICOS */
|
|
|
|
/* Log before sending the reply */
|
|
auth_log(authctxt, authenticated, method, " ssh2");
|
|
|
|
if (authctxt->postponed)
|
|
return;
|
|
|
|
/* XXX todo: check if multiple auth methods are needed */
|
|
if (authenticated == 1) {
|
|
/* turn off userauth */
|
|
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
|
|
packet_start(SSH2_MSG_USERAUTH_SUCCESS);
|
|
packet_send();
|
|
packet_write_wait();
|
|
/* now we can break out */
|
|
authctxt->success = 1;
|
|
} else {
|
|
if (authctxt->failures++ > AUTH_FAIL_MAX) {
|
|
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
|
|
}
|
|
#ifdef _UNICOS
|
|
if (strcmp(method, "password") == 0)
|
|
cray_login_failure(authctxt->user, IA_UDBERR);
|
|
#endif /* _UNICOS */
|
|
methods = authmethods_get();
|
|
packet_start(SSH2_MSG_USERAUTH_FAILURE);
|
|
packet_put_cstring(methods);
|
|
packet_put_char(0); /* XXX partial success, unused */
|
|
packet_send();
|
|
packet_write_wait();
|
|
xfree(methods);
|
|
}
|
|
}
|
|
|
|
/* get current user */
|
|
|
|
struct passwd*
|
|
auth_get_user(void)
|
|
{
|
|
return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
|
|
}
|
|
|
|
#define DELIM ","
|
|
|
|
static char *
|
|
authmethods_get(void)
|
|
{
|
|
Buffer b;
|
|
char *list;
|
|
int i;
|
|
|
|
buffer_init(&b);
|
|
for (i = 0; authmethods[i] != NULL; i++) {
|
|
if (strcmp(authmethods[i]->name, "none") == 0)
|
|
continue;
|
|
if (authmethods[i]->enabled != NULL &&
|
|
*(authmethods[i]->enabled) != 0) {
|
|
if (buffer_len(&b) > 0)
|
|
buffer_append(&b, ",", 1);
|
|
buffer_append(&b, authmethods[i]->name,
|
|
strlen(authmethods[i]->name));
|
|
}
|
|
}
|
|
buffer_append(&b, "\0", 1);
|
|
list = xstrdup(buffer_ptr(&b));
|
|
buffer_free(&b);
|
|
return list;
|
|
}
|
|
|
|
static Authmethod *
|
|
authmethod_lookup(const char *name)
|
|
{
|
|
int i;
|
|
|
|
if (name != NULL)
|
|
for (i = 0; authmethods[i] != NULL; i++)
|
|
if (authmethods[i]->enabled != NULL &&
|
|
*(authmethods[i]->enabled) != 0 &&
|
|
strcmp(name, authmethods[i]->name) == 0)
|
|
return authmethods[i];
|
|
debug2("Unrecognized authentication method name: %s",
|
|
name ? name : "NULL");
|
|
return NULL;
|
|
}
|