Mercurial > dropbear

changeset 249:efbaf6b03837

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added keyboard-interactive client support
author Matt Johnston <matt@ucc.asn.au>
date Tue, 20 Sep 2005 17:35:21 +0000
parents bf64e666f99b
children d059b0bb57dd
files Makefile.in auth.h cli-auth.c cli-authinteract.c cli-authpasswd.c cli-session.c options.h session.h ssh.h
diffstat 9 files changed, 282 insertions(+), 18 deletions(-) [+]
line wrap: on
line diff
--- a/Makefile.in	Tue Sep 20 08:59:46 2005 +0000
+++ b/Makefile.in	Tue Sep 20 17:35:21 2005 +0000
@@ -29,7 +29,7 @@
 
 CLIOBJS=cli-algo.o cli-main.o cli-auth.o cli-authpasswd.o cli-kex.o \
 		cli-session.o cli-service.o cli-runopts.o cli-chansession.o \
-		cli-authpubkey.o cli-tcpfwd.o cli-channel.o
+		cli-authpubkey.o cli-tcpfwd.o cli-channel.o cli-authinteract.o
 
 CLISVROBJS=common-session.o packet.o common-algo.o common-kex.o \
 			common-channel.o common-chansession.o termcodes.o loginrec.o \
--- a/auth.h	Tue Sep 20 08:59:46 2005 +0000
+++ b/auth.h	Tue Sep 20 17:35:21 2005 +0000
@@ -41,28 +41,36 @@
 /* Client functions */
 void recv_msg_userauth_failure();
 void recv_msg_userauth_success();
+void recv_msg_userauth_specific_60();
 void recv_msg_userauth_pk_ok();
+void recv_msg_userauth_info_request();
 void cli_get_user();
 void cli_auth_getmethods();
 void cli_auth_try();
 void recv_msg_userauth_banner();
 void cli_pubkeyfail();
-int cli_auth_password();
+void cli_auth_password();
 int cli_auth_pubkey();
+void cli_auth_interactive();
 
 
 #define MAX_USERNAME_LEN 25 /* arbitrary for the moment */
 
-#define AUTH_TYPE_PUBKEY	1 << 0
-#define AUTH_TYPE_PASSWORD	1 << 1
+#define AUTH_TYPE_NONE      1
+#define AUTH_TYPE_PUBKEY    1 << 1
+#define AUTH_TYPE_PASSWORD  1 << 2
+#define AUTH_TYPE_INTERACT  1 << 3
 
-/* auth types, "none" means we should return list of acceptable types */
-#define AUTH_METHOD_NONE	"none"
+#define AUTH_METHOD_NONE "none"
 #define AUTH_METHOD_NONE_LEN 4
 #define AUTH_METHOD_PUBKEY "publickey"
 #define AUTH_METHOD_PUBKEY_LEN 9
 #define AUTH_METHOD_PASSWORD "password"
 #define AUTH_METHOD_PASSWORD_LEN 8
+#define AUTH_METHOD_INTERACT "keyboard-interactive"
+#define AUTH_METHOD_INTERACT_LEN 20
+
+
 
 /* This structure is shared between server and client - it contains
  * relatively little extraneous bits when used for the client rather than the
--- a/cli-auth.c	Tue Sep 20 08:59:46 2005 +0000
+++ b/cli-auth.c	Tue Sep 20 17:35:21 2005 +0000
@@ -32,7 +32,6 @@
 #include "packet.h"
 #include "runopts.h"
 
-
 void cli_authinitialise() {
 
 	memset(&ses.authstate, 0, sizeof(ses.authstate));
@@ -99,6 +98,40 @@
 	TRACE(("leave recv_msg_userauth_banner"))
 }
 
+/* This handles the message-specific types which
+ * all have a value of 60. These are
+ * SSH_MSG_USERAUTH_PASSWD_CHANGEREQ,
+ * SSH_MSG_USERAUTH_PK_OK, &
+ * SSH_MSG_USERAUTH_INFO_REQUEST. */
+void recv_msg_userauth_specific_60() {
+
+#ifdef ENABLE_CLI_PUBKEY_AUTH
+	if (cli_ses.lastauthtype == AUTH_TYPE_PUBKEY) {
+		recv_msg_userauth_pk_ok();
+		return;
+	}
+#endif
+
+#ifdef ENABLE_CLI_INTERACT_AUTH
+	if (cli_ses.lastauthtype == AUTH_TYPE_INTERACT) {
+		recv_msg_userauth_info_request();
+		return;
+	}
+#endif
+
+#ifdef ENABLE_CLI_PASSWORD_AUTH
+	if (cli_ses.lastauthtype == AUTH_TYPE_PASSWORD) {
+		/* Eventually there could be proper password-changing
+		 * support. However currently few servers seem to
+		 * implement it, and password auth is last-resort
+		 * regardless - keyboard-interactive is more likely
+		 * to be used anyway. */
+		dropbear_close("Your password has expired.");
+	}
+#endif
+
+	dropbear_exit("Unexpected userauth packet");
+}
 
 void recv_msg_userauth_failure() {
 
@@ -113,8 +146,7 @@
 
 	if (cli_ses.state != USERAUTH_REQ_SENT) {
 		/* Perhaps we should be more fatal? */
-		TRACE(("But we didn't send a userauth request!!!!!!"))
-		return;
+		dropbear_exit("Unexpected userauth failure");
 	}
 
 #ifdef ENABLE_CLI_PUBKEY_AUTH
@@ -125,6 +157,19 @@
 	}
 #endif
 
+#ifdef ENABLE_CLI_INTERACT_AUTH
+	/* If we get a failure message for keyboard interactive without
+	 * receiving any request info packet, then we don't bother trying
+	 * keyboard interactive again */
+	if (cli_ses.lastauthtype == AUTH_TYPE_INTERACT
+			&& !cli_ses.interact_request_received) {
+		TRACE(("setting auth_interact_failed = 1"))
+		cli_ses.auth_interact_failed = 1;
+	}
+#endif
+
+	cli_ses.lastauthtype = AUTH_TYPE_NONE;
+
 	methods = buf_getstring(ses.payload, &methlen);
 
 	partial = buf_getbool(ses.payload);
@@ -157,6 +202,12 @@
 				ses.authstate.authtypes |= AUTH_TYPE_PUBKEY;
 			}
 #endif
+#ifdef ENABLE_CLI_INTERACT_AUTH
+			if (strncmp(AUTH_METHOD_INTERACT, tok,
+				AUTH_METHOD_INTERACT_LEN) == 0) {
+				ses.authstate.authtypes |= AUTH_TYPE_INTERACT;
+			}
+#endif
 #ifdef ENABLE_CLI_PASSWORD_AUTH
 			if (strncmp(AUTH_METHOD_PASSWORD, tok,
 				AUTH_METHOD_PASSWORD_LEN) == 0) {
@@ -180,6 +231,7 @@
 	TRACE(("received msg_userauth_success"))
 	ses.authstate.authdone = 1;
 	cli_ses.state = USERAUTH_SUCCESS_RCVD;
+	cli_ses.lastauthtype = AUTH_TYPE_NONE;
 }
 
 void cli_auth_try() {
@@ -189,7 +241,8 @@
 
 	CHECKCLEARTOWRITE();
 	
-	/* XXX We hardcode that we try a pubkey first */
+	/* Order to try is pubkey, interactive, password.
+	 * As soon as "finished" is set for one, we don't do any more. */
 #ifdef ENABLE_CLI_PUBKEY_AUTH
 	if (ses.authstate.authtypes & AUTH_TYPE_PUBKEY) {
 		finished = cli_auth_pubkey();
@@ -197,13 +250,28 @@
 	}
 #endif
 
+#ifdef ENABLE_CLI_INTERACT_AUTH
+	if (!finished && ses.authstate.authtypes & AUTH_TYPE_INTERACT) {
+		if (cli_ses.auth_interact_failed) {
+			finished = 0;
+		} else {
+			cli_auth_interactive();
+			cli_ses.lastauthtype = AUTH_TYPE_INTERACT;
+			finished = 1;
+		}
+	}
+#endif
+
 #ifdef ENABLE_CLI_PASSWORD_AUTH
 	if (!finished && ses.authstate.authtypes & AUTH_TYPE_PASSWORD) {
-		finished = cli_auth_password();
+		cli_auth_password();
+		finished = 1;
 		cli_ses.lastauthtype = AUTH_TYPE_PASSWORD;
 	}
 #endif
 
+	TRACE(("cli_auth_try lastauthtype %d", cli_ses.lastauthtype))
+
 	if (!finished) {
 		dropbear_exit("No auth methods could be used.");
 	}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cli-authinteract.c	Tue Sep 20 17:35:21 2005 +0000
@@ -0,0 +1,168 @@
+/*
+ * Dropbear SSH
+ * 
+ * Copyright (c) 2005 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "buffer.h"
+#include "dbutil.h"
+#include "session.h"
+#include "ssh.h"
+#include "runopts.h"
+
+#ifdef ENABLE_CLI_INTERACT_AUTH
+
+static unsigned char* get_response(unsigned char* prompt)
+{
+	FILE* tty = NULL;
+	unsigned char* response = NULL;
+	/* not a password, but a reasonable limit */
+	char buf[DROPBEAR_MAX_CLI_PASS];
+	char* ret = NULL;
+
+	fprintf(stderr, "%s", prompt);
+
+	tty = fopen(_PATH_TTY, "r");
+	if (tty) {
+		ret = fgets(buf, sizeof(buf), tty);
+		fclose(tty);
+	} else {
+		ret = fgets(buf, sizeof(buf), stdin);
+	}
+
+	if (ret == NULL) {
+		response = (unsigned char*)m_strdup("");
+	} else {
+		unsigned int buflen = strlen(buf);
+		/* fgets includes newlines */
+		if (buflen > 0 && buf[buflen-1] == '\n')
+			buf[buflen-1] = '\0';
+		response = (unsigned char*)m_strdup(buf);
+	}
+
+	m_burn(buf, sizeof(buf));
+
+	return response;
+}
+
+void recv_msg_userauth_info_request() {
+
+	unsigned char *name = NULL;
+	unsigned char *instruction = NULL;
+	unsigned int num_prompts = 0;
+	unsigned int i;
+
+	unsigned char *prompt = NULL;
+	unsigned int echo = 0;
+	unsigned char *response = NULL;
+
+	TRACE(("enter recv_msg_recv_userauth_info_request"))
+
+	cli_ses.interact_request_received = 1;
+
+	name = buf_getstring(ses.payload, NULL);
+	instruction = buf_getstring(ses.payload, NULL);
+
+	/* language tag */
+	buf_eatstring(ses.payload);
+
+	num_prompts = buf_getint(ses.payload);
+	
+	if (num_prompts >= DROPBEAR_MAX_CLI_INTERACT_PROMPTS) {
+		dropbear_exit("Too many prompts received for keyboard-interactive");
+	}
+
+	/* we'll build the response as we go */
+	CHECKCLEARTOWRITE();
+	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_INFO_RESPONSE);
+	buf_putint(ses.writepayload, num_prompts);
+
+	if (strlen(name) > 0) {
+		cleantext(name);
+		fprintf(stderr, "%s", name);
+		m_free(name);
+	}
+	if (strlen(instruction) > 0) {
+		cleantext(instruction);
+		fprintf(stderr, "%s", instruction);
+		m_free(instruction);
+	}
+
+	for (i = 0; i < num_prompts; i++) {
+		unsigned int response_len = 0;
+		prompt = buf_getstring(ses.payload, NULL);
+		cleantext(prompt);
+
+		echo = buf_getbool(ses.payload);
+
+		if (echo) {
+			unsigned char* p = getpass(prompt);
+			response = m_strdup(p);
+			m_burn(p, strlen(p));
+		} else {
+			response = get_response(prompt);
+		}
+
+		response_len = strlen(response);
+		buf_putstring(ses.writepayload, response, response_len);
+		m_burn(response, response_len);
+		m_free(response);
+	}
+
+	encrypt_packet();
+
+
+	TRACE(("leave recv_msg_recv_userauth_info_request"))
+}
+
+void cli_auth_interactive() {
+
+	TRACE(("enter cli_auth_interactive"))
+	CHECKCLEARTOWRITE();
+
+	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST);
+
+	/* username */
+	buf_putstring(ses.writepayload, cli_opts.username,
+			strlen(cli_opts.username));
+
+	/* service name */
+	buf_putstring(ses.writepayload, SSH_SERVICE_CONNECTION, 
+			SSH_SERVICE_CONNECTION_LEN);
+
+	/* method */
+	buf_putstring(ses.writepayload, AUTH_METHOD_INTERACT,
+			AUTH_METHOD_INTERACT_LEN);
+
+	/* empty language tag */
+	buf_putstring(ses.writepayload, "", 0);
+
+	/* empty submethods */
+	buf_putstring(ses.writepayload, "", 0);
+
+	encrypt_packet();
+	cli_ses.interact_request_received = 0;
+
+	TRACE(("leave cli_auth_interactive"))
+
+}
+#endif	/* ENABLE_CLI_INTERACT_AUTH */
--- a/cli-authpasswd.c	Tue Sep 20 08:59:46 2005 +0000
+++ b/cli-authpasswd.c	Tue Sep 20 17:35:21 2005 +0000
@@ -113,7 +113,7 @@
 }
 #endif /* ENABLE_CLI_ASKPASS_HELPER */
 
-int cli_auth_password() {
+void cli_auth_password() {
 
 	char* password = NULL;
 
@@ -149,7 +149,5 @@
 	m_burn(password, strlen(password));
 
 	TRACE(("leave cli_auth_password"))
-	return 1; /* Password auth can always be tried */
-
 }
 #endif	/* ENABLE_CLI_PASSWORD_AUTH */
--- a/cli-session.c	Tue Sep 20 08:59:46 2005 +0000
+++ b/cli-session.c	Tue Sep 20 17:35:21 2005 +0000
@@ -63,9 +63,7 @@
 	{SSH_MSG_CHANNEL_OPEN_CONFIRMATION, recv_msg_channel_open_confirmation},
 	{SSH_MSG_CHANNEL_OPEN_FAILURE, recv_msg_channel_open_failure},
 	{SSH_MSG_USERAUTH_BANNER, recv_msg_userauth_banner}, /* client */
-#ifdef ENABLE_CLI_PUBKEY_AUTH
-	{SSH_MSG_USERAUTH_PK_OK, recv_msg_userauth_pk_ok}, /* client */
-#endif
+	{SSH_MSG_USERAUTH_SPECIFIC_60, recv_msg_userauth_specific_60}, /* client */
 	{0, 0} /* End */
 };
 
@@ -285,7 +283,8 @@
 }
 
 /* Operates in-place turning dirty (untrusted potentially containing control
- * characters) text into clean text. */
+ * characters) text into clean text. 
+ * Note: this is safe only with ascii - other charsets could have problems. */
 void cleantext(unsigned char* dirtytext) {
 
 	unsigned int i, j;
--- a/options.h	Tue Sep 20 08:59:46 2005 +0000
+++ b/options.h	Tue Sep 20 17:35:21 2005 +0000
@@ -133,6 +133,7 @@
 
 #define ENABLE_CLI_PASSWORD_AUTH
 #define ENABLE_CLI_PUBKEY_AUTH
+#define ENABLE_CLI_INTERACT_AUTH
 
 /* Define this (as well as ENABLE_CLI_PASSWORD_AUTH) to allow the use of
  * a helper program for the ssh client. The helper program should be
@@ -315,6 +316,10 @@
 
 #define DROPBEAR_MAX_CLI_PASS 1024
 
+#define DROPBEAR_MAX_CLI_INTERACT_PROMPTS 80 /* The number of prompts we'll 
+												accept for keyb-interactive
+												auth */
+
 #if defined(DROPBEAR_AES256_CBC) || defined(DROPBEAR_AES128_CBC)
 #define DROPBEAR_AES_CBC
 #endif
--- a/session.h	Tue Sep 20 08:59:46 2005 +0000
+++ b/session.h	Tue Sep 20 17:35:21 2005 +0000
@@ -226,6 +226,13 @@
 
 	int lastauthtype; /* either AUTH_TYPE_PUBKEY or AUTH_TYPE_PASSWORD,
 						 for the last type of auth we tried */
+#ifdef ENABLE_CLI_INTERACT_AUTH
+	int auth_interact_failed; /* flag whether interactive auth can still
+								 be used */
+	int interact_request_received; /* flag whether we've received an 
+									  info request from the server for
+									  interactive auth.*/
+#endif
 	struct SignKeyList *lastprivkey;
 
 	int retval; /* What the command exit status was - we emulate it */
--- a/ssh.h	Tue Sep 20 08:59:46 2005 +0000
+++ b/ssh.h	Tue Sep 20 17:35:21 2005 +0000
@@ -42,8 +42,19 @@
 #define SSH_MSG_USERAUTH_FAILURE            51
 #define SSH_MSG_USERAUTH_SUCCESS            52
 #define SSH_MSG_USERAUTH_BANNER             53
+
+/* packets 60-79 are method-specific, aren't one-one mapping */
+#define SSH_MSG_USERAUTH_SPECIFIC_60   60
+
+#define SSH_MSG_USERAUTH_PASSWD_CHANGEREQ   60
+
 #define SSH_MSG_USERAUTH_PK_OK				60
 
+/* keyboard interactive auth */
+#define SSH_MSG_USERAUTH_INFO_REQUEST           60
+#define SSH_MSG_USERAUTH_INFO_RESPONSE          61
+
+
 /* If adding numbers here, check MAX_UNAUTH_PACKET_TYPE in process-packet.c
  * is still valid */