Mercurial > dropbear

changeset 22:c1e5d9195402

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merge of abac2150ee4f4031a98016241fbd136d24fed127 and ffa047425729e478a5b49b1ab0f8ec71c08a1421
author Matt Johnston <matt@ucc.asn.au>
date Wed, 23 Jun 2004 07:14:16 +0000
parents 5ae28f6101c1 (diff) d7cc5b484a2e (current diff)
children c896a4dd65da
files common-kex.c common-packet.c common-session.c debug.h packet.h process-packet.c session.h ssh.h svr-auth.c svr-kex.c svr-packet.c svr-service.c svr-session.c
diffstat 13 files changed, 220 insertions(+), 227 deletions(-) [+]
line wrap: on
line diff
--- a/common-kex.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/common-kex.c	Wed Jun 23 07:14:16 2004 +0000
@@ -450,8 +450,8 @@
 	/* the rest of ses.kexhashbuf will be done after DH exchange */
 
 	ses.kexstate.recvkexinit = 1;
-//	ses.expecting = SSH_MSG_KEXDH_INIT;
-	ses.expecting = 0;
+	ses.requirenext = SSH_MSG_KEXDH_INIT;
+//	ses.expecting = 0; // client matt
 
 	TRACE(("leave recv_msg_kexinit"));
 }
--- a/common-packet.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/common-packet.c	Wed Jun 23 07:14:16 2004 +0000
@@ -402,21 +402,6 @@
 
 
 
-/* This must be called directly after receiving the unimplemented packet.
- * Isn't the most clean implementation, it relies on packet processing
- * occurring directly after decryption. This is reasonably valid, since
- * there is only a single decryption buffer */
-void recv_unimplemented() {
-
-	CHECKCLEARTOWRITE();
-
-	buf_putbyte(ses.writepayload, SSH_MSG_UNIMPLEMENTED);
-	/* the decryption routine increments the sequence number, we must
-	 * decrement */
-	buf_putint(ses.writepayload, ses.recvseq - 1);
-
-	encrypt_packet();
-}
 	
 /* encrypt the writepayload, putting into writebuf, ready for write_packet()
  * to put on the wire */
--- a/common-session.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/common-session.c	Wed Jun 23 07:14:16 2004 +0000
@@ -76,7 +76,7 @@
 	ses.payload = NULL;
 	ses.recvseq = 0;
 
-	ses.expecting = SSH_MSG_KEXINIT;
+	ses.requirenext = SSH_MSG_KEXINIT;
 	ses.dataallowed = 0; /* don't send data yet, we'll wait until after kex */
 	ses.ignorenext = 0;
 
@@ -106,6 +106,8 @@
 	ses.dh_K = NULL;
 	ses.remoteident = NULL;
 
+	ses.authdone = 0;
+
 	ses.chantypes = NULL;
 
 	ses.allowprivport = 0;
--- a/debug.h	Tue Jun 22 10:47:16 2004 +0000
+++ b/debug.h	Wed Jun 23 07:14:16 2004 +0000
@@ -36,7 +36,7 @@
 /* Define this to print trace statements - very verbose */
 /* Caution: Don't use this in an unfriendly environment (ie unfirewalled),
  * since the printing does not sanitise strings etc */
-/*#define DEBUG_TRACE*/
+#define DEBUG_TRACE
 
 /* All functions writing to the cleartext payload buffer call
  * CHECKCLEARTOWRITE() before writing. This is only really useful if you're
--- a/packet.h	Tue Jun 22 10:47:16 2004 +0000
+++ b/packet.h	Wed Jun 23 07:14:16 2004 +0000
@@ -32,9 +32,13 @@
 void read_packet();
 void decrypt_packet();
 void encrypt_packet();
-void recv_unimplemented();
+
+void process_packet();
 
-void svr_process_packet();
+typedef struct PacketType {
+	unsigned char type; /* SSH_MSG_FOO */
+	void (*handler)();
+} packettype;
 
 #define PACKET_PADDING_OFF 4
 #define PACKET_PAYLOAD_OFF 5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/process-packet.c	Wed Jun 23 07:14:16 2004 +0000
@@ -0,0 +1,161 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002-2004 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 "packet.h"
+#include "session.h"
+#include "dbutil.h"
+#include "ssh.h"
+#include "algo.h"
+#include "buffer.h"
+#include "kex.h"
+#include "random.h"
+#include "service.h"
+#include "auth.h"
+#include "channel.h"
+
+#define MAX_UNAUTH_PACKET_TYPE SSH_MSG_USERAUTH_PK_OK
+
+static void recv_unimplemented();
+
+/* process a decrypted packet, call the appropriate handler */
+void process_packet() {
+
+	unsigned char type;
+	unsigned int i;
+
+	TRACE(("enter process_packet"));
+
+	type = buf_getbyte(ses.payload);
+	TRACE(("process_packet: packet type = %d", type));
+
+	/* These packets we can receive at any time */
+	switch(type) {
+
+		case SSH_MSG_IGNORE:
+		case SSH_MSG_DEBUG:
+			TRACE(("received SSH_MSG_IGNORE or SSH_MSG_DEBUG"));
+			goto out;
+
+		case SSH_MSG_UNIMPLEMENTED:
+			/* debugging XXX */
+			TRACE(("SSH_MSG_UNIMPLEMENTED"));
+			dropbear_exit("received SSH_MSG_UNIMPLEMENTED");
+			
+		case SSH_MSG_DISCONNECT:
+			/* TODO cleanup? */
+			dropbear_close("Disconnect received");
+	}
+
+
+	/* This applies for KEX, where the spec says the next packet MUST be
+	 * NEWKEYS */
+	if (ses.requirenext != 0) {
+		if (ses.requirenext != type) {
+			/* TODO send disconnect? */
+			dropbear_exit("unexpected packet type %d, expected %d", type,
+					ses.requirenext);
+		} else {
+			/* Got what we expected */
+			ses.requirenext = 0;
+		}
+	}
+
+	/* Check if we should ignore this packet. Used currently only for
+	 * KEX code, with first_kex_packet_follows */
+	if (ses.ignorenext) {
+		TRACE(("Ignoring packet, type = %d", type));
+		ses.ignorenext = 0;
+		goto out;
+	}
+
+	/* XXX This code somewhere else perhaps? */
+#ifdef DROPBEAR_CLIENT
+	if (IS_DROPBEAR_CLIENT) {
+
+		/* XXX - needs changing */
+		/* In client mode, we REUSE ses.expecting to proceed to the 
+		 *  next phase when a packet was received.
+		 * If the "expecting" flag is set to a non-null value, it will 
+		 *  be reset when a packet of that type is received.
+		 * This is different from the server-mode behaviour, when 
+		 *  a packet type mismatch would have caused sudden death.
+		 */
+		 
+		/* check that we aren't expecting a particular packet */
+		if (cli_ses.expecting && cli_ses.expecting == type) {
+			cli_ses.expecting = 0;
+		}
+	}
+#endif
+
+	/* Kindly the protocol authors gave all the preauth packets type values
+	 * less-than-or-equal-to 60 ( == MAX_UNAUTH_PACKET_TYPE ).
+	 * NOTE: if the protocol changes and new types are added, revisit this 
+	 * assumption */
+	if ( !ses.authdone && type > MAX_UNAUTH_PACKET_TYPE ) {
+		dropbear_exit("received message %d before userauth", type);
+	}
+
+	for (i = 0; ; i++) {
+		if (ses.packettypes[i].type == 0) {
+			/* end of list */
+			break;
+		}
+
+		if (ses.packettypes[i].type == type) {
+			ses.packettypes[i].handler();
+			goto out;
+		}
+	}
+
+	
+	/* TODO do something more here? */
+	TRACE(("preauth unknown packet"));
+	recv_unimplemented();
+
+out:
+	buf_free(ses.payload);
+	ses.payload = NULL;
+
+	TRACE(("leave process_packet"));
+}
+
+
+
+/* This must be called directly after receiving the unimplemented packet.
+ * Isn't the most clean implementation, it relies on packet processing
+ * occurring directly after decryption (direct use of ses.recvseq).
+ * This is reasonably valid, since there is only a single decryption buffer */
+static void recv_unimplemented() {
+
+	CHECKCLEARTOWRITE();
+
+	buf_putbyte(ses.writepayload, SSH_MSG_UNIMPLEMENTED);
+	/* the decryption routine increments the sequence number, we must
+	 * decrement */
+	buf_putint(ses.writepayload, ses.recvseq - 1);
+
+	encrypt_packet();
+}
--- a/session.h	Tue Jun 22 10:47:16 2004 +0000
+++ b/session.h	Wed Jun 23 07:14:16 2004 +0000
@@ -34,6 +34,7 @@
 #include "queue.h"
 #include "runopts.h"
 #include "listener.h"
+#include "packet.h"
 
 extern int sessinitdone; /* Is set to 0 somewhere */
 extern int exitflag;
@@ -106,10 +107,13 @@
 	unsigned int transseq, recvseq; /* Sequence IDs */
 
 	/* Packet-handling flags */
+	const packettype * packettypes; /* Packet handler mappings for this
+										session, see process-packet.c */
+
 	unsigned dataallowed : 1; /* whether we can send data packets or we are in
 								 the middle of a KEX or something */
 
-	unsigned char expecting; /* byte indicating what packet we expect next, 
+	unsigned char requirenext; /* byte indicating what packet we require next, 
 								or 0x00 for any */
 
 	unsigned char ignorenext; /* whether to ignore the next packet,
@@ -130,6 +134,12 @@
 							 can add it to the hash when generating keys */
 
 
+	unsigned char authdone;	/* Indicates when authentication has been
+							   completed. This applies to both client and
+							   server - in the server it gets set to 1 when
+							   authentication is successful, in the client it
+							   is set when the server has told us that auth
+							   succeeded */
 
 	/* Channel related */
 	struct Channel ** channels; /* these pointers may be null */
--- a/ssh.h	Tue Jun 22 10:47:16 2004 +0000
+++ b/ssh.h	Wed Jun 23 07:14:16 2004 +0000
@@ -44,6 +44,9 @@
 #define SSH_MSG_USERAUTH_BANNER             53
 #define SSH_MSG_USERAUTH_PK_OK				60
 
+/* If adding numbers here, check MAX_UNAUTH_PACKET_TYPE in process-packet.c
+ * is still valid */
+
 /* connect message numbers */
 #define SSH_MSG_GLOBAL_REQUEST                  80
 #define SSH_MSG_REQUEST_SUCCESS                 81
--- a/svr-auth.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/svr-auth.c	Wed Jun 23 07:14:16 2004 +0000
@@ -52,7 +52,7 @@
  * on initialisation */
 static void authclear() {
 	
-	svr_ses.authstate.authdone = 0;
+	ses.authdone = 0;
 	svr_ses.authstate.pw = NULL;
 	svr_ses.authstate.username = NULL;
 	svr_ses.authstate.printableuser = NULL;
@@ -102,7 +102,7 @@
 	TRACE(("enter recv_msg_userauth_request"));
 
 	/* ignore packets if auth is already done */
-	if (svr_ses.authstate.authdone == 1) {
+	if (ses.authdone == 1) {
 		return;
 	}
 
@@ -339,7 +339,7 @@
 	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_SUCCESS);
 	encrypt_packet();
 
-	svr_ses.authstate.authdone = 1;
+	ses.authdone = 1;
 
 	if (svr_ses.authstate.pw->pw_uid == 0) {
 		ses.allowprivport = 1;
--- a/svr-kex.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/svr-kex.c	Wed Jun 23 07:14:16 2004 +0000
@@ -57,7 +57,7 @@
 	mp_clear(&dh_e);
 
 	send_msg_newkeys();
-	ses.expecting = SSH_MSG_NEWKEYS;
+	ses.requirenext = SSH_MSG_NEWKEYS;
 	TRACE(("leave recv_msg_kexdh_init"));
 }
 	
--- a/svr-packet.c	Tue Jun 22 10:47:16 2004 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,196 +0,0 @@
-/*
- * Dropbear - a SSH2 server
- * 
- * Copyright (c) 2002,2003 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 "packet.h"
-#include "session.h"
-#include "dbutil.h"
-#include "ssh.h"
-#include "algo.h"
-#include "buffer.h"
-#include "kex.h"
-#include "random.h"
-#include "service.h"
-#include "auth.h"
-#include "channel.h"
-
-static void svr_process_postauth_packet(unsigned int type);
-
-/* process a decrypted packet, call the appropriate handler */
-void svr_process_packet() {
-
-	unsigned char type;
-
-	TRACE(("enter process_packet"));
-
-	type = buf_getbyte(ses.payload);
-	TRACE(("process_packet: packet type = %d", type));
-
-	/* these packets we can receive at any time, regardless of expecting
-	 * other packets: */
-	switch(type) {
-
-		case SSH_MSG_IGNORE:
-		case SSH_MSG_DEBUG:
-			TRACE(("received SSH_MSG_IGNORE or SSH_MSG_DEBUG"));
-			goto out;
-
-		case SSH_MSG_UNIMPLEMENTED:
-			/* debugging XXX */
-			TRACE(("SSH_MSG_UNIMPLEMENTED"));
-			dropbear_exit("received SSH_MSG_UNIMPLEMENTED");
-			
-		case SSH_MSG_DISCONNECT:
-			/* TODO cleanup? */
-			dropbear_close("Disconnect received");
-	}
-
-	/* Check if we should ignore this packet. Used currently only for
-	 * KEX code, with first_kex_packet_follows */
-	if (ses.ignorenext) {
-		TRACE(("Ignoring packet, type = %d", type));
-		ses.ignorenext = 0;
-		goto out;
-	}
-
-	/* check that we aren't expecting a particular packet */
-	if (ses.expecting && ses.expecting != type) {
-		/* TODO send disconnect? */
-		dropbear_exit("unexpected packet type %d, expected %d", type,
-				ses.expecting);
-	}
-
-	/* handle the packet depending on type */
-	ses.expecting = 0;
-
-	switch (type) {
-
-		case SSH_MSG_SERVICE_REQUEST:
-			recv_msg_service_request();
-			break;
-
-		case SSH_MSG_USERAUTH_REQUEST:
-			recv_msg_userauth_request();
-			break;
-			
-		case SSH_MSG_KEXINIT:
-			recv_msg_kexinit();
-			break;
-
-		case SSH_MSG_KEXDH_INIT:
-			recv_msg_kexdh_init();
-			break;
-
-		case SSH_MSG_NEWKEYS:
-			recv_msg_newkeys();
-			break;
-
-		/* this is ugly, need to make a cleaner way to do it */
-		case SSH_MSG_CHANNEL_DATA:
-		case SSH_MSG_CHANNEL_WINDOW_ADJUST:
-		case SSH_MSG_CHANNEL_REQUEST:
-		case SSH_MSG_CHANNEL_OPEN:
-		case SSH_MSG_CHANNEL_EOF:
-		case SSH_MSG_CHANNEL_CLOSE:
-		case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
-		case SSH_MSG_CHANNEL_OPEN_FAILURE:
-		case SSH_MSG_GLOBAL_REQUEST:
-			/* these should be checked for authdone below */
-			svr_process_postauth_packet(type);
-			break;
-	
-		default:
-			/* TODO this possibly should be handled */
-			TRACE(("preauth unknown packet"));
-			recv_unimplemented();
-			break;
-	}
-
-out:
-	buf_free(ses.payload);
-	ses.payload = NULL;
-
-	TRACE(("leave process_packet"));
-}
-
-/* process a packet, and also check that auth has been done */
-static void svr_process_postauth_packet(unsigned int type) {
-
-	/* messages following here require userauth before use */
-
-	/* IF YOU ADD MORE PACKET TYPES, MAKE SURE THEY'RE ALSO ADDED TO THE LIST
-	 * IN process_packet() XXX XXX XXX */
-	if (!svr_ses.authstate.authdone) {
-		dropbear_exit("received message %d before userauth", type);
-	}
-
-	switch (type) {
-
-		case SSH_MSG_CHANNEL_DATA:
-			recv_msg_channel_data();
-			break;
-
-		case SSH_MSG_CHANNEL_WINDOW_ADJUST:
-			recv_msg_channel_window_adjust();
-			break;
-
-#ifndef DISABLE_REMOTETCPFWD
-		case SSH_MSG_GLOBAL_REQUEST:
-			/* currently only used for remote tcp, so we cheat a little */
-			recv_msg_global_request_remotetcp();
-			break;
-#endif
-
-		case SSH_MSG_CHANNEL_REQUEST:
-			recv_msg_channel_request();
-			break;
-
-		case SSH_MSG_CHANNEL_OPEN:
-			recv_msg_channel_open();
-			break;
-
-		case SSH_MSG_CHANNEL_EOF:
-			recv_msg_channel_eof();
-			break;
-
-		case SSH_MSG_CHANNEL_CLOSE:
-			recv_msg_channel_close();
-			break;
-
-#ifdef USING_LISTENERS /* for x11, tcp fwd etc */
-		case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
-			recv_msg_channel_open_confirmation();
-			break;
-			
-		case SSH_MSG_CHANNEL_OPEN_FAILURE:
-			recv_msg_channel_open_failure();
-			break;
-#endif
-			
-		default:
-			TRACE(("unknown packet()"));
-			recv_unimplemented();
-			break;
-	}
-}
--- a/svr-service.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/svr-service.c	Wed Jun 23 07:14:16 2004 +0000
@@ -56,7 +56,7 @@
 	/* ssh-connection */
 	if (len == SSH_SERVICE_CONNECTION_LEN &&
 			(strncmp(SSH_SERVICE_CONNECTION, name, len) == 0)) {
-		if (svr_ses.authstate.authdone != 1) {
+		if (ses.authdone != 1) {
 			dropbear_exit("request for connection before auth");
 		}
 
--- a/svr-session.c	Tue Jun 22 10:47:16 2004 +0000
+++ b/svr-session.c	Wed Jun 23 07:14:16 2004 +0000
@@ -36,18 +36,39 @@
 #include "chansession.h"
 #include "atomicio.h"
 #include "tcpfwd-direct.h"
+#include "service.h"
+#include "auth.h"
+#include "tcpfwd-remote.h"
 
 static void svr_remoteclosed();
 
 struct serversession svr_ses;
 
-const struct ChanType *chantypes[] = {
+static const packettype svr_packettypes[] = {
+	/* TYPE, AUTHREQUIRED, FUNCTION */
+	{SSH_MSG_SERVICE_REQUEST, recv_msg_service_request}, // server
+	{SSH_MSG_USERAUTH_REQUEST, recv_msg_userauth_request}, //server
+	{SSH_MSG_KEXINIT, recv_msg_kexinit},
+	{SSH_MSG_KEXDH_INIT, recv_msg_kexdh_init},
+	{SSH_MSG_NEWKEYS, recv_msg_newkeys},
+	{SSH_MSG_CHANNEL_DATA, recv_msg_channel_data},
+	{SSH_MSG_CHANNEL_WINDOW_ADJUST, recv_msg_channel_window_adjust},
+	{SSH_MSG_GLOBAL_REQUEST, recv_msg_global_request_remotetcp},
+	{SSH_MSG_CHANNEL_REQUEST, recv_msg_channel_request},
+	{SSH_MSG_CHANNEL_OPEN, recv_msg_channel_open},
+	{SSH_MSG_CHANNEL_EOF, recv_msg_channel_eof},
+	{SSH_MSG_CHANNEL_CLOSE, recv_msg_channel_close},
+	{SSH_MSG_CHANNEL_OPEN_CONFIRMATION, recv_msg_channel_open_confirmation},
+	{SSH_MSG_CHANNEL_OPEN_FAILURE, recv_msg_channel_open_failure},
+	{0, 0} /* End */
+};
+
+static const struct ChanType *svr_chantypes[] = {
 	&svrchansess,
 	&chan_tcpdirect,
 	NULL /* Null termination is mandatory. */
 };
 
-
 void svr_session(int sock, runopts *opts, int childpipe, 
 		struct sockaddr* remoteaddr) {
 
@@ -64,7 +85,7 @@
 	/* Initialise server specific parts of the session */
 	svr_ses.childpipe = childpipe;
 	authinitialise();
-	chaninitialise(chantypes);
+	chaninitialise(svr_chantypes);
 	svr_chansessinitialise();
 
 	if (gettimeofday(&timeout, 0) < 0) {
@@ -76,6 +97,9 @@
 	/* set up messages etc */
 	session_remoteclosed = svr_remoteclosed;
 
+	/* packet handlers */
+	ses.packettypes = svr_packettypes;
+
 	/* We're ready to go now */
 	sessinitdone = 1;
 
@@ -145,7 +169,7 @@
 			/* Process the decrypted packet. After this, the read buffer
 			 * will be ready for a new packet */
 			if (ses.payload != NULL) {
-				svr_process_packet();
+				process_packet();
 			}
 		}