1 files changed, 329 insertions, 0 deletions
diff --git a/crypto/openssh/auth2.c b/crypto/openssh/auth2.c
new file mode 100644
index 0000000..2d880b5
--- /dev/null
+++ b/crypto/openssh/auth2.c
@@ -0,0 +1,329 @@
+/* $OpenBSD: auth2.c,v 1.113 2006/08/03 03:34:41 deraadt Exp $ */
+/*
+ * 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"
+
+#include <sys/types.h>
+
+#include <pwd.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include "xmalloc.h"
+#include "ssh2.h"
+#include "packet.h"
+#include "log.h"
+#include "buffer.h"
+#include "servconf.h"
+#include "compat.h"
+#include "key.h"
+#include "hostfile.h"
+#include "auth.h"
+#include "dispatch.h"
+#include "pathnames.h"
+#include "buffer.h"
+
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "monitor_wrap.h"
+
+/* import */
+extern ServerOptions options;
+extern u_char *session_id2;
+extern u_int session_id2_len;
+extern Buffer loginmsg;
+
+/* methods */
+
+extern Authmethod method_none;
+extern Authmethod method_pubkey;
+extern Authmethod method_passwd;
+extern Authmethod method_kbdint;
+extern Authmethod method_hostbased;
+#ifdef GSSAPI
+extern Authmethod method_gssapi;
+#endif
+
+Authmethod *authmethods[] = {
+	&method_none,
+	&method_pubkey,
+#ifdef GSSAPI
+	&method_gssapi,
+#endif
+	&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 *);
+
+/*
+ * loop until authctxt->success == TRUE
+ */
+
+void
+do_authentication2(Authctxt *authctxt)
+{
+	/* challenge-response is implemented via keyboard interactive */
+	if (options.challenge_response_authentication)
+		options.kbd_interactive_authentication = 1;
+
+	dispatch_init(&dispatch_protocol_error);
+	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
+	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
+}
+
+/*ARGSUSED*/
+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);
+}
+
+/*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_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));
+		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 : "unknown",
+		    use_privsep ? " [net]" : "");
+		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);
+
+#ifdef GSSAPI
+	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
+	dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
+#endif
+
+	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 SSH_AUDIT_EVENTS
+		PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
+#endif
+	}
+
+#ifdef USE_PAM
+	if (options.use_pam && authenticated) {
+		if (!PRIVSEP(do_pam_account())) {
+			/* if PAM returned a message, send it to the user */
+			if (buffer_len(&loginmsg) > 0) {
+				buffer_append(&loginmsg, "\0", 1);
+				userauth_send_banner(buffer_ptr(&loginmsg));
+				packet_write_wait();
+			}
+			fatal("Access denied for user %s by PAM account "
+			    "configuration", authctxt->user);
+		}
+	}
+#endif
+
+#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++ > options.max_authtries) {
+#ifdef SSH_AUDIT_EVENTS
+			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
+#endif
+			packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
+		}
+		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);
+	}
+}
+
+#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;
+}