X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/e5c59e3105fb3cd82a12266130010d092e22bf0b..HEAD:/auth2.c

diff --git a/auth2.c b/auth2.c
index 515033f4..5d546855 100644
--- a/auth2.c
+++ b/auth2.c
@@ -1,3 +1,4 @@
+/* $OpenBSD: auth2.c,v 1.121 2009/06/22 05:39:28 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  *
@@ -23,25 +24,42 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.93 2002/05/31 11:35:15 markus Exp $");
 
-#include "ssh2.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/uio.h>
+
+#include <fcntl.h>
+#include <pwd.h>
+#include <stdarg.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "atomicio.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 int session_id2_len;
-
-Authctxt *x_authctxt = NULL;
+extern u_int session_id2_len;
+extern Buffer loginmsg;
 
 /* methods */
 
@@ -50,10 +68,22 @@ extern Authmethod method_pubkey;
 extern Authmethod method_passwd;
 extern Authmethod method_kbdint;
 extern Authmethod method_hostbased;
+#ifdef GSSAPI
+extern Authmethod method_gssapi;
+#endif
+#ifdef JPAKE
+extern Authmethod method_jpake;
+#endif
 
 Authmethod *authmethods[] = {
 	&method_none,
 	&method_pubkey,
+#ifdef GSSAPI
+	&method_gssapi,
+#endif
+#ifdef JPAKE
+	&method_jpake,
+#endif
 	&method_passwd,
 	&method_kbdint,
 	&method_hostbased,
@@ -68,41 +98,90 @@ 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
- */
+char *
+auth2_read_banner(void)
+{
+	struct stat st;
+	char *banner = NULL;
+	size_t len, n;
+	int fd;
+
+	if ((fd = open(options.banner, O_RDONLY)) == -1)
+		return (NULL);
+	if (fstat(fd, &st) == -1) {
+		close(fd);
+		return (NULL);
+	}
+	if (st.st_size > 1*1024*1024) {
+		close(fd);
+		return (NULL);
+	}
+
+	len = (size_t)st.st_size;		/* truncate */
+	banner = xmalloc(len + 1);
+	n = atomicio(read, fd, banner, len);
+	close(fd);
+
+	if (n != len) {
+		xfree(banner);
+		return (NULL);
+	}
+	banner[n] = '\0';
+
+	return (banner);
+}
+
+void
+userauth_send_banner(const char *msg)
+{
+	if (datafellows & SSH_BUG_BANNER)
+		return;
+
+	packet_start(SSH2_MSG_USERAUTH_BANNER);
+	packet_put_cstring(msg);
+	packet_put_cstring("");		/* language, unused */
+	packet_send();
+	debug("%s: sent", __func__);
+}
 
-Authctxt *
-do_authentication2(void)
+static void
+userauth_banner(void)
 {
-	Authctxt *authctxt = authctxt_new();
+	char *banner = NULL;
+
+	if (options.banner == NULL ||
+	    strcasecmp(options.banner, "none") == 0 ||
+	    (datafellows & SSH_BUG_BANNER) != 0)
+		return;
 
-	x_authctxt = authctxt;		/*XXX*/
+	if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
+		goto done;
+	userauth_send_banner(banner);
 
-	/* 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;
+done:
+	if (banner)
+		xfree(banner);
+}
 
+/*
+ * loop until authctxt->success == TRUE
+ */
+void
+do_authentication2(Authctxt *authctxt)
+{
 	dispatch_init(&dispatch_protocol_error);
 	dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
 	dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
-
-	return (authctxt);
 }
 
+/*ARGSUSED*/
 static void
 input_service_request(int type, u_int32_t seq, void *ctxt)
 {
 	Authctxt *authctxt = ctxt;
 	u_int len;
-	int accept = 0;
+	int acceptit = 0;
 	char *service = packet_get_string(&len);
 	packet_check_eom();
 
@@ -111,14 +190,14 @@ input_service_request(int type, u_int32_t seq, void *ctxt)
 
 	if (strcmp(service, "ssh-userauth") == 0) {
 		if (!authctxt->success) {
-			accept = 1;
+			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 (accept) {
+	if (acceptit) {
 		packet_start(SSH2_MSG_SERVICE_ACCEPT);
 		packet_put_cstring(service);
 		packet_send();
@@ -130,6 +209,7 @@ input_service_request(int type, u_int32_t seq, void *ctxt)
 	xfree(service);
 }
 
+/*ARGSUSED*/
 static void
 input_userauth_request(int type, u_int32_t seq, void *ctxt)
 {
@@ -153,25 +233,28 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 	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);
-#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"));
+			logit("input_userauth_request: invalid user %s", user);
+			authctxt->pw = fakepw();
+#ifdef SSH_AUDIT_EVENTS
+			PRIVSEP(audit_event(SSH_INVALID_USER));
 #endif
 		}
-		setproctitle("%s%s", authctxt->pw ? user : "unknown",
+#ifdef USE_PAM
+		if (options.use_pam)
+			PRIVSEP(start_pam(authctxt));
+#endif
+		setproctitle("%s%s", authctxt->valid ? 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);
+		userauth_banner();
 	} else if (strcmp(user, authctxt->user) != 0 ||
 	    strcmp(service, authctxt->service) != 0) {
 		packet_disconnect("Change of username or service not allowed: "
@@ -180,11 +263,21 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 	}
 	/* 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;
 
 	/* try to authenticate user */
 	m = authmethod_lookup(method);
-	if (m != NULL) {
+	if (m != NULL && authctxt->failures < options.max_authtries) {
 		debug2("input_userauth_request: try method %s", method);
 		authenticated =	m->userauth(authctxt);
 	}
@@ -206,14 +299,34 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 
 	/* Special handling for root */
 	if (authenticated && authctxt->pw->pw_uid == 0 &&
-	    !auth_root_allowed(method))
+	    !auth_root_allowed(method)) {
 		authenticated = 0;
+#ifdef SSH_AUDIT_EVENTS
+		PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
+#endif
+	}
 
 #ifdef USE_PAM
-	if (!use_privsep && authenticated && authctxt->user && 
-	    !do_pam_account(authctxt->user, NULL))
+	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;
-#endif /* USE_PAM */
+		fatal("Access denied for user %s.",authctxt->user);
+	}
+#endif /* _UNICOS */
 
 	/* Log before sending the reply */
 	auth_log(authctxt, authenticated, method, " ssh2");
@@ -231,12 +344,14 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 		/* now we can break out */
 		authctxt->success = 1;
 	} else {
-		if (authctxt->failures++ > AUTH_FAIL_MAX) {
-#ifdef WITH_AIXAUTHENTICATE
-			loginfailed(authctxt->user,
-			    get_canonical_hostname(options.verify_reverse_mapping),
-			    "ssh");
-#endif /* WITH_AIXAUTHENTICATE */
+
+		/* Allow initial try of "none" auth without failure penalty */
+		if (authctxt->attempt > 1 || strcmp(method, "none") != 0)
+			authctxt->failures++;
+		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();
@@ -249,16 +364,6 @@ userauth_finish(Authctxt *authctxt, int authenticated, char *method)
 	}
 }
 
-/* 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)
 {
@@ -299,3 +404,4 @@ authmethod_lookup(const char *name)
 	    name ? name : "NULL");
 	return NULL;
 }
+