Revert part of 180714 - the intent was to flatten dist, not to nuke it.

1 files changed, 1609 insertions, 0 deletions

diff --git a/crypto/openssh/packet.c b/crypto/openssh/packet.c
new file mode 100644
index 0000000..ab5a010
--- /dev/null
+++ b/crypto/openssh/packet.c
@@ -0,0 +1,1609 @@
+/* $OpenBSD: packet.c,v 1.145 2006/09/19 21:14:08 markus Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * This file contains code implementing the packet protocol and communication
+ * with the other side.  This same code is used both on client and server side.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ *
+ * SSH2 packet format added by Markus Friedl.
+ * Copyright (c) 2000, 2001 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 "openbsd-compat/sys-queue.h"
+#include <sys/param.h>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include "xmalloc.h"
+#include "buffer.h"
+#include "packet.h"
+#include "crc32.h"
+#include "compress.h"
+#include "deattack.h"
+#include "channels.h"
+#include "compat.h"
+#include "ssh1.h"
+#include "ssh2.h"
+#include "cipher.h"
+#include "key.h"
+#include "kex.h"
+#include "mac.h"
+#include "log.h"
+#include "canohost.h"
+#include "misc.h"
+#include "ssh.h"
+
+#ifdef PACKET_DEBUG
+#define DBG(x) x
+#else
+#define DBG(x)
+#endif
+
+/*
+ * This variable contains the file descriptors used for communicating with
+ * the other side.  connection_in is used for reading; connection_out for
+ * writing.  These can be the same descriptor, in which case it is assumed to
+ * be a socket.
+ */
+static int connection_in = -1;
+static int connection_out = -1;
+
+/* Protocol flags for the remote side. */
+static u_int remote_protocol_flags = 0;
+
+/* Encryption context for receiving data.  This is only used for decryption. */
+static CipherContext receive_context;
+
+/* Encryption context for sending data.  This is only used for encryption. */
+static CipherContext send_context;
+
+/* Buffer for raw input data from the socket. */
+Buffer input;
+
+/* Buffer for raw output data going to the socket. */
+Buffer output;
+
+/* Buffer for the partial outgoing packet being constructed. */
+static Buffer outgoing_packet;
+
+/* Buffer for the incoming packet currently being processed. */
+static Buffer incoming_packet;
+
+/* Scratch buffer for packet compression/decompression. */
+static Buffer compression_buffer;
+static int compression_buffer_ready = 0;
+
+/* Flag indicating whether packet compression/decompression is enabled. */
+static int packet_compression = 0;
+
+/* default maximum packet size */
+u_int max_packet_size = 32768;
+
+/* Flag indicating whether this module has been initialized. */
+static int initialized = 0;
+
+/* Set to true if the connection is interactive. */
+static int interactive_mode = 0;
+
+/* Set to true if we are the server side. */
+static int server_side = 0;
+
+/* Set to true if we are authenticated. */
+static int after_authentication = 0;
+
+/* Session key information for Encryption and MAC */
+Newkeys *newkeys[MODE_MAX];
+static struct packet_state {
+	u_int32_t seqnr;
+	u_int32_t packets;
+	u_int64_t blocks;
+} p_read, p_send;
+
+static u_int64_t max_blocks_in, max_blocks_out;
+static u_int32_t rekey_limit;
+
+/* Session key for protocol v1 */
+static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
+static u_int ssh1_keylen;
+
+/* roundup current message to extra_pad bytes */
+static u_char extra_pad = 0;
+
+struct packet {
+	TAILQ_ENTRY(packet) next;
+	u_char type;
+	Buffer payload;
+};
+TAILQ_HEAD(, packet) outgoing;
+
+/*
+ * Sets the descriptors used for communication.  Disables encryption until
+ * packet_set_encryption_key is called.
+ */
+void
+packet_set_connection(int fd_in, int fd_out)
+{
+	Cipher *none = cipher_by_name("none");
+
+	if (none == NULL)
+		fatal("packet_set_connection: cannot load cipher 'none'");
+	connection_in = fd_in;
+	connection_out = fd_out;
+	cipher_init(&send_context, none, (const u_char *)"",
+	    0, NULL, 0, CIPHER_ENCRYPT);
+	cipher_init(&receive_context, none, (const u_char *)"",
+	    0, NULL, 0, CIPHER_DECRYPT);
+	newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
+	if (!initialized) {
+		initialized = 1;
+		buffer_init(&input);
+		buffer_init(&output);
+		buffer_init(&outgoing_packet);
+		buffer_init(&incoming_packet);
+		TAILQ_INIT(&outgoing);
+	}
+}
+
+/* Returns 1 if remote host is connected via socket, 0 if not. */
+
+int
+packet_connection_is_on_socket(void)
+{
+	struct sockaddr_storage from, to;
+	socklen_t fromlen, tolen;
+
+	/* filedescriptors in and out are the same, so it's a socket */
+	if (connection_in == connection_out)
+		return 1;
+	fromlen = sizeof(from);
+	memset(&from, 0, sizeof(from));
+	if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
+		return 0;
+	tolen = sizeof(to);
+	memset(&to, 0, sizeof(to));
+	if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
+		return 0;
+	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
+		return 0;
+	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
+		return 0;
+	return 1;
+}
+
+/*
+ * Exports an IV from the CipherContext required to export the key
+ * state back from the unprivileged child to the privileged parent
+ * process.
+ */
+
+void
+packet_get_keyiv(int mode, u_char *iv, u_int len)
+{
+	CipherContext *cc;
+
+	if (mode == MODE_OUT)
+		cc = &send_context;
+	else
+		cc = &receive_context;
+
+	cipher_get_keyiv(cc, iv, len);
+}
+
+int
+packet_get_keycontext(int mode, u_char *dat)
+{
+	CipherContext *cc;
+
+	if (mode == MODE_OUT)
+		cc = &send_context;
+	else
+		cc = &receive_context;
+
+	return (cipher_get_keycontext(cc, dat));
+}
+
+void
+packet_set_keycontext(int mode, u_char *dat)
+{
+	CipherContext *cc;
+
+	if (mode == MODE_OUT)
+		cc = &send_context;
+	else
+		cc = &receive_context;
+
+	cipher_set_keycontext(cc, dat);
+}
+
+int
+packet_get_keyiv_len(int mode)
+{
+	CipherContext *cc;
+
+	if (mode == MODE_OUT)
+		cc = &send_context;
+	else
+		cc = &receive_context;
+
+	return (cipher_get_keyiv_len(cc));
+}
+
+void
+packet_set_iv(int mode, u_char *dat)
+{
+	CipherContext *cc;
+
+	if (mode == MODE_OUT)
+		cc = &send_context;
+	else
+		cc = &receive_context;
+
+	cipher_set_keyiv(cc, dat);
+}
+
+int
+packet_get_ssh1_cipher(void)
+{
+	return (cipher_get_number(receive_context.cipher));
+}
+
+void
+packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets)
+{
+	struct packet_state *state;
+
+	state = (mode == MODE_IN) ? &p_read : &p_send;
+	*seqnr = state->seqnr;
+	*blocks = state->blocks;
+	*packets = state->packets;
+}
+
+void
+packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets)
+{
+	struct packet_state *state;
+
+	state = (mode == MODE_IN) ? &p_read : &p_send;
+	state->seqnr = seqnr;
+	state->blocks = blocks;
+	state->packets = packets;
+}
+
+/* returns 1 if connection is via ipv4 */
+
+int
+packet_connection_is_ipv4(void)
+{
+	struct sockaddr_storage to;
+	socklen_t tolen = sizeof(to);
+
+	memset(&to, 0, sizeof(to));
+	if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
+		return 0;
+	if (to.ss_family == AF_INET)
+		return 1;
+#ifdef IPV4_IN_IPV6
+	if (to.ss_family == AF_INET6 &&
+	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
+		return 1;
+#endif
+	return 0;
+}
+
+/* Sets the connection into non-blocking mode. */
+
+void
+packet_set_nonblocking(void)
+{
+	/* Set the socket into non-blocking mode. */
+	set_nonblock(connection_in);
+
+	if (connection_out != connection_in)
+		set_nonblock(connection_out);
+}
+
+/* Returns the socket used for reading. */
+
+int
+packet_get_connection_in(void)
+{
+	return connection_in;
+}
+
+/* Returns the descriptor used for writing. */
+
+int
+packet_get_connection_out(void)
+{
+	return connection_out;
+}
+
+/* Closes the connection and clears and frees internal data structures. */
+
+void
+packet_close(void)
+{
+	if (!initialized)
+		return;
+	initialized = 0;
+	if (connection_in == connection_out) {
+		shutdown(connection_out, SHUT_RDWR);
+		close(connection_out);
+	} else {
+		close(connection_in);
+		close(connection_out);
+	}
+	buffer_free(&input);
+	buffer_free(&output);
+	buffer_free(&outgoing_packet);
+	buffer_free(&incoming_packet);
+	if (compression_buffer_ready) {
+		buffer_free(&compression_buffer);
+		buffer_compress_uninit();
+	}
+	cipher_cleanup(&send_context);
+	cipher_cleanup(&receive_context);
+}
+
+/* Sets remote side protocol flags. */
+
+void
+packet_set_protocol_flags(u_int protocol_flags)
+{
+	remote_protocol_flags = protocol_flags;
+}
+
+/* Returns the remote protocol flags set earlier by the above function. */
+
+u_int
+packet_get_protocol_flags(void)
+{
+	return remote_protocol_flags;
+}
+
+/*
+ * Starts packet compression from the next packet on in both directions.
+ * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
+ */
+
+static void
+packet_init_compression(void)
+{
+	if (compression_buffer_ready == 1)
+		return;
+	compression_buffer_ready = 1;
+	buffer_init(&compression_buffer);
+}
+
+void
+packet_start_compression(int level)
+{
+	if (packet_compression && !compat20)
+		fatal("Compression already enabled.");
+	packet_compression = 1;
+	packet_init_compression();
+	buffer_compress_init_send(level);
+	buffer_compress_init_recv();
+}
+
+/*
+ * Causes any further packets to be encrypted using the given key.  The same
+ * key is used for both sending and reception.  However, both directions are
+ * encrypted independently of each other.
+ */
+
+void
+packet_set_encryption_key(const u_char *key, u_int keylen,
+    int number)
+{
+	Cipher *cipher = cipher_by_number(number);
+
+	if (cipher == NULL)
+		fatal("packet_set_encryption_key: unknown cipher number %d", number);
+	if (keylen < 20)
+		fatal("packet_set_encryption_key: keylen too small: %d", keylen);
+	if (keylen > SSH_SESSION_KEY_LENGTH)
+		fatal("packet_set_encryption_key: keylen too big: %d", keylen);
+	memcpy(ssh1_key, key, keylen);
+	ssh1_keylen = keylen;
+	cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
+	cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
+}
+
+u_int
+packet_get_encryption_key(u_char *key)
+{
+	if (key == NULL)
+		return (ssh1_keylen);
+	memcpy(key, ssh1_key, ssh1_keylen);
+	return (ssh1_keylen);
+}
+
+/* Start constructing a packet to send. */
+void
+packet_start(u_char type)
+{
+	u_char buf[9];
+	int len;
+
+	DBG(debug("packet_start[%d]", type));
+	len = compat20 ? 6 : 9;
+	memset(buf, 0, len - 1);
+	buf[len - 1] = type;
+	buffer_clear(&outgoing_packet);
+	buffer_append(&outgoing_packet, buf, len);
+}
+
+/* Append payload. */
+void
+packet_put_char(int value)
+{
+	char ch = value;
+
+	buffer_append(&outgoing_packet, &ch, 1);
+}
+
+void
+packet_put_int(u_int value)
+{
+	buffer_put_int(&outgoing_packet, value);
+}
+
+void
+packet_put_string(const void *buf, u_int len)
+{
+	buffer_put_string(&outgoing_packet, buf, len);
+}
+
+void
+packet_put_cstring(const char *str)
+{
+	buffer_put_cstring(&outgoing_packet, str);
+}
+
+void
+packet_put_raw(const void *buf, u_int len)
+{
+	buffer_append(&outgoing_packet, buf, len);
+}
+
+void
+packet_put_bignum(BIGNUM * value)
+{
+	buffer_put_bignum(&outgoing_packet, value);
+}
+
+void
+packet_put_bignum2(BIGNUM * value)
+{
+	buffer_put_bignum2(&outgoing_packet, value);
+}
+
+/*
+ * Finalizes and sends the packet.  If the encryption key has been set,
+ * encrypts the packet before sending.
+ */
+
+static void
+packet_send1(void)
+{
+	u_char buf[8], *cp;
+	int i, padding, len;
+	u_int checksum;
+	u_int32_t rnd = 0;
+
+	/*
+	 * If using packet compression, compress the payload of the outgoing
+	 * packet.
+	 */
+	if (packet_compression) {
+		buffer_clear(&compression_buffer);
+		/* Skip padding. */
+		buffer_consume(&outgoing_packet, 8);
+		/* padding */
+		buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
+		buffer_compress(&outgoing_packet, &compression_buffer);
+		buffer_clear(&outgoing_packet);
+		buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
+		    buffer_len(&compression_buffer));
+	}
+	/* Compute packet length without padding (add checksum, remove padding). */
+	len = buffer_len(&outgoing_packet) + 4 - 8;
+
+	/* Insert padding. Initialized to zero in packet_start1() */
+	padding = 8 - len % 8;
+	if (!send_context.plaintext) {
+		cp = buffer_ptr(&outgoing_packet);
+		for (i = 0; i < padding; i++) {
+			if (i % 4 == 0)
+				rnd = arc4random();
+			cp[7 - i] = rnd & 0xff;
+			rnd >>= 8;
+		}
+	}
+	buffer_consume(&outgoing_packet, 8 - padding);
+
+	/* Add check bytes. */
+	checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
+	    buffer_len(&outgoing_packet));
+	put_u32(buf, checksum);
+	buffer_append(&outgoing_packet, buf, 4);
+
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "packet_send plain: ");
+	buffer_dump(&outgoing_packet);
+#endif
+
+	/* Append to output. */
+	put_u32(buf, len);
+	buffer_append(&output, buf, 4);
+	cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
+	cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+	    buffer_len(&outgoing_packet));
+
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "encrypted: ");
+	buffer_dump(&output);
+#endif
+
+	buffer_clear(&outgoing_packet);
+
+	/*
+	 * Note that the packet is now only buffered in output.  It won't be
+	 * actually sent until packet_write_wait or packet_write_poll is
+	 * called.
+	 */
+}
+
+void
+set_newkeys(int mode)
+{
+	Enc *enc;
+	Mac *mac;
+	Comp *comp;
+	CipherContext *cc;
+	u_int64_t *max_blocks;
+	int crypt_type;
+
+	debug2("set_newkeys: mode %d", mode);
+
+	if (mode == MODE_OUT) {
+		cc = &send_context;
+		crypt_type = CIPHER_ENCRYPT;
+		p_send.packets = p_send.blocks = 0;
+		max_blocks = &max_blocks_out;
+	} else {
+		cc = &receive_context;
+		crypt_type = CIPHER_DECRYPT;
+		p_read.packets = p_read.blocks = 0;
+		max_blocks = &max_blocks_in;
+	}
+	if (newkeys[mode] != NULL) {
+		debug("set_newkeys: rekeying");
+		cipher_cleanup(cc);
+		enc  = &newkeys[mode]->enc;
+		mac  = &newkeys[mode]->mac;
+		comp = &newkeys[mode]->comp;
+		memset(mac->key, 0, mac->key_len);
+		xfree(enc->name);
+		xfree(enc->iv);
+		xfree(enc->key);
+		xfree(mac->name);
+		xfree(mac->key);
+		xfree(comp->name);
+		xfree(newkeys[mode]);
+	}
+	newkeys[mode] = kex_get_newkeys(mode);
+	if (newkeys[mode] == NULL)
+		fatal("newkeys: no keys for mode %d", mode);
+	enc  = &newkeys[mode]->enc;
+	mac  = &newkeys[mode]->mac;
+	comp = &newkeys[mode]->comp;
+	if (mac->md != NULL)
+		mac->enabled = 1;
+	DBG(debug("cipher_init_context: %d", mode));
+	cipher_init(cc, enc->cipher, enc->key, enc->key_len,
+	    enc->iv, enc->block_size, crypt_type);
+	/* Deleting the keys does not gain extra security */
+	/* memset(enc->iv,  0, enc->block_size);
+	   memset(enc->key, 0, enc->key_len); */
+	if ((comp->type == COMP_ZLIB ||
+	    (comp->type == COMP_DELAYED && after_authentication)) &&
+	    comp->enabled == 0) {
+		packet_init_compression();
+		if (mode == MODE_OUT)
+			buffer_compress_init_send(6);
+		else
+			buffer_compress_init_recv();
+		comp->enabled = 1;
+	}
+	/*
+	 * The 2^(blocksize*2) limit is too expensive for 3DES,
+	 * blowfish, etc, so enforce a 1GB limit for small blocksizes.
+	 */
+	if (enc->block_size >= 16)
+		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
+	else
+		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
+	if (rekey_limit)
+		*max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
+}
+
+/*
+ * Delayed compression for SSH2 is enabled after authentication:
+ * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
+ * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
+ */
+static void
+packet_enable_delayed_compress(void)
+{
+	Comp *comp = NULL;
+	int mode;
+
+	/*
+	 * Remember that we are past the authentication step, so rekeying
+	 * with COMP_DELAYED will turn on compression immediately.
+	 */
+	after_authentication = 1;
+	for (mode = 0; mode < MODE_MAX; mode++) {
+		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
+		if (newkeys[mode] == NULL)
+			continue;
+		comp = &newkeys[mode]->comp;
+		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
+			packet_init_compression();
+			if (mode == MODE_OUT)
+				buffer_compress_init_send(6);
+			else
+				buffer_compress_init_recv();
+			comp->enabled = 1;
+		}
+	}
+}
+
+/*
+ * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
+ */
+static void
+packet_send2_wrapped(void)
+{
+	u_char type, *cp, *macbuf = NULL;
+	u_char padlen, pad;
+	u_int packet_length = 0;
+	u_int i, len;
+	u_int32_t rnd = 0;
+	Enc *enc   = NULL;
+	Mac *mac   = NULL;
+	Comp *comp = NULL;
+	int block_size;
+
+	if (newkeys[MODE_OUT] != NULL) {
+		enc  = &newkeys[MODE_OUT]->enc;
+		mac  = &newkeys[MODE_OUT]->mac;
+		comp = &newkeys[MODE_OUT]->comp;
+	}
+	block_size = enc ? enc->block_size : 8;
+
+	cp = buffer_ptr(&outgoing_packet);
+	type = cp[5];
+
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "plain:     ");
+	buffer_dump(&outgoing_packet);
+#endif
+
+	if (comp && comp->enabled) {
+		len = buffer_len(&outgoing_packet);
+		/* skip header, compress only payload */
+		buffer_consume(&outgoing_packet, 5);
+		buffer_clear(&compression_buffer);
+		buffer_compress(&outgoing_packet, &compression_buffer);
+		buffer_clear(&outgoing_packet);
+		buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
+		buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
+		    buffer_len(&compression_buffer));
+		DBG(debug("compression: raw %d compressed %d", len,
+		    buffer_len(&outgoing_packet)));
+	}
+
+	/* sizeof (packet_len + pad_len + payload) */
+	len = buffer_len(&outgoing_packet);
+
+	/*
+	 * calc size of padding, alloc space, get random data,
+	 * minimum padding is 4 bytes
+	 */
+	padlen = block_size - (len % block_size);
+	if (padlen < 4)
+		padlen += block_size;
+	if (extra_pad) {
+		/* will wrap if extra_pad+padlen > 255 */
+		extra_pad  = roundup(extra_pad, block_size);
+		pad = extra_pad - ((len + padlen) % extra_pad);
+		debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
+		    pad, len, padlen, extra_pad);
+		padlen += pad;
+		extra_pad = 0;
+	}
+	cp = buffer_append_space(&outgoing_packet, padlen);
+	if (enc && !send_context.plaintext) {
+		/* random padding */
+		for (i = 0; i < padlen; i++) {
+			if (i % 4 == 0)
+				rnd = arc4random();
+			cp[i] = rnd & 0xff;
+			rnd >>= 8;
+		}
+	} else {
+		/* clear padding */
+		memset(cp, 0, padlen);
+	}
+	/* packet_length includes payload, padding and padding length field */
+	packet_length = buffer_len(&outgoing_packet) - 4;
+	cp = buffer_ptr(&outgoing_packet);
+	put_u32(cp, packet_length);
+	cp[4] = padlen;
+	DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
+
+	/* compute MAC over seqnr and packet(length fields, payload, padding) */
+	if (mac && mac->enabled) {
+		macbuf = mac_compute(mac, p_send.seqnr,
+		    buffer_ptr(&outgoing_packet),
+		    buffer_len(&outgoing_packet));
+		DBG(debug("done calc MAC out #%d", p_send.seqnr));
+	}
+	/* encrypt packet and append to output buffer. */
+	cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
+	cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+	    buffer_len(&outgoing_packet));
+	/* append unencrypted MAC */
+	if (mac && mac->enabled)
+		buffer_append(&output, macbuf, mac->mac_len);
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "encrypted: ");
+	buffer_dump(&output);
+#endif
+	/* increment sequence number for outgoing packets */
+	if (++p_send.seqnr == 0)
+		logit("outgoing seqnr wraps around");
+	if (++p_send.packets == 0)
+		if (!(datafellows & SSH_BUG_NOREKEY))
+			fatal("XXX too many packets with same key");
+	p_send.blocks += (packet_length + 4) / block_size;
+	buffer_clear(&outgoing_packet);
+
+	if (type == SSH2_MSG_NEWKEYS)
+		set_newkeys(MODE_OUT);
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
+		packet_enable_delayed_compress();
+}
+
+static void
+packet_send2(void)
+{
+	static int rekeying = 0;
+	struct packet *p;
+	u_char type, *cp;
+
+	cp = buffer_ptr(&outgoing_packet);
+	type = cp[5];
+
+	/* during rekeying we can only send key exchange messages */
+	if (rekeying) {
+		if (!((type >= SSH2_MSG_TRANSPORT_MIN) &&
+		    (type <= SSH2_MSG_TRANSPORT_MAX))) {
+			debug("enqueue packet: %u", type);
+			p = xmalloc(sizeof(*p));
+			p->type = type;
+			memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
+			buffer_init(&outgoing_packet);
+			TAILQ_INSERT_TAIL(&outgoing, p, next);
+			return;
+		}
+	}
+
+	/* rekeying starts with sending KEXINIT */
+	if (type == SSH2_MSG_KEXINIT)
+		rekeying = 1;
+
+	packet_send2_wrapped();
+
+	/* after a NEWKEYS message we can send the complete queue */
+	if (type == SSH2_MSG_NEWKEYS) {
+		rekeying = 0;
+		while ((p = TAILQ_FIRST(&outgoing))) {
+			type = p->type;
+			debug("dequeue packet: %u", type);
+			buffer_free(&outgoing_packet);
+			memcpy(&outgoing_packet, &p->payload,
+			    sizeof(Buffer));
+			TAILQ_REMOVE(&outgoing, p, next);
+			xfree(p);
+			packet_send2_wrapped();
+		}
+	}
+}
+
+void
+packet_send(void)
+{
+	if (compat20)
+		packet_send2();
+	else
+		packet_send1();
+	DBG(debug("packet_send done"));
+}
+
+/*
+ * Waits until a packet has been received, and returns its type.  Note that
+ * no other data is processed until this returns, so this function should not
+ * be used during the interactive session.
+ */
+
+int
+packet_read_seqnr(u_int32_t *seqnr_p)
+{
+	int type, len;
+	fd_set *setp;
+	char buf[8192];
+	DBG(debug("packet_read()"));
+
+	setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS),
+	    sizeof(fd_mask));
+
+	/* Since we are blocking, ensure that all written packets have been sent. */
+	packet_write_wait();
+
+	/* Stay in the loop until we have received a complete packet. */
+	for (;;) {
+		/* Try to read a packet from the buffer. */
+		type = packet_read_poll_seqnr(seqnr_p);
+		if (!compat20 && (
+		    type == SSH_SMSG_SUCCESS
+		    || type == SSH_SMSG_FAILURE
+		    || type == SSH_CMSG_EOF
+		    || type == SSH_CMSG_EXIT_CONFIRMATION))
+			packet_check_eom();
+		/* If we got a packet, return it. */
+		if (type != SSH_MSG_NONE) {
+			xfree(setp);
+			return type;
+		}
+		/*
+		 * Otherwise, wait for some data to arrive, add it to the
+		 * buffer, and try again.
+		 */
+		memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
+		    sizeof(fd_mask));
+		FD_SET(connection_in, setp);
+
+		/* Wait for some data to arrive. */
+		while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
+		    (errno == EAGAIN || errno == EINTR))
+			;
+
+		/* Read data from the socket. */
+		len = read(connection_in, buf, sizeof(buf));
+		if (len == 0) {
+			logit("Connection closed by %.200s", get_remote_ipaddr());
+			cleanup_exit(255);
+		}
+		if (len < 0)
+			fatal("Read from socket failed: %.100s", strerror(errno));
+		/* Append it to the buffer. */
+		packet_process_incoming(buf, len);
+	}
+	/* NOTREACHED */
+}
+
+int
+packet_read(void)
+{
+	return packet_read_seqnr(NULL);
+}
+
+/*
+ * Waits until a packet has been received, verifies that its type matches
+ * that given, and gives a fatal error and exits if there is a mismatch.
+ */
+
+void
+packet_read_expect(int expected_type)
+{
+	int type;
+
+	type = packet_read();
+	if (type != expected_type)
+		packet_disconnect("Protocol error: expected packet type %d, got %d",
+		    expected_type, type);
+}
+
+/* Checks if a full packet is available in the data received so far via
+ * packet_process_incoming.  If so, reads the packet; otherwise returns
+ * SSH_MSG_NONE.  This does not wait for data from the connection.
+ *
+ * SSH_MSG_DISCONNECT is handled specially here.  Also,
+ * SSH_MSG_IGNORE messages are skipped by this function and are never returned
+ * to higher levels.
+ */
+
+static int
+packet_read_poll1(void)
+{
+	u_int len, padded_len;
+	u_char *cp, type;
+	u_int checksum, stored_checksum;
+
+	/* Check if input size is less than minimum packet size. */
+	if (buffer_len(&input) < 4 + 8)
+		return SSH_MSG_NONE;
+	/* Get length of incoming packet. */
+	cp = buffer_ptr(&input);
+	len = get_u32(cp);
+	if (len < 1 + 2 + 2 || len > 256 * 1024)
+		packet_disconnect("Bad packet length %u.", len);
+	padded_len = (len + 8) & ~7;
+
+	/* Check if the packet has been entirely received. */
+	if (buffer_len(&input) < 4 + padded_len)
+		return SSH_MSG_NONE;
+
+	/* The entire packet is in buffer. */
+
+	/* Consume packet length. */
+	buffer_consume(&input, 4);
+
+	/*
+	 * Cryptographic attack detector for ssh
+	 * (C)1998 CORE-SDI, Buenos Aires Argentina
+	 * Ariel Futoransky(futo@core-sdi.com)
+	 */
+	if (!receive_context.plaintext) {
+		switch (detect_attack(buffer_ptr(&input), padded_len)) {
+		case DEATTACK_DETECTED:
+			packet_disconnect("crc32 compensation attack: "
+			    "network attack detected");
+		case DEATTACK_DOS_DETECTED:
+			packet_disconnect("deattack denial of "
+			    "service detected");
+		}
+	}
+
+	/* Decrypt data to incoming_packet. */
+	buffer_clear(&incoming_packet);
+	cp = buffer_append_space(&incoming_packet, padded_len);
+	cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
+
+	buffer_consume(&input, padded_len);
+
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "read_poll plain: ");
+	buffer_dump(&incoming_packet);
+#endif
+
+	/* Compute packet checksum. */
+	checksum = ssh_crc32(buffer_ptr(&incoming_packet),
+	    buffer_len(&incoming_packet) - 4);
+
+	/* Skip padding. */
+	buffer_consume(&incoming_packet, 8 - len % 8);
+
+	/* Test check bytes. */
+	if (len != buffer_len(&incoming_packet))
+		packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
+		    len, buffer_len(&incoming_packet));
+
+	cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
+	stored_checksum = get_u32(cp);
+	if (checksum != stored_checksum)
+		packet_disconnect("Corrupted check bytes on input.");
+	buffer_consume_end(&incoming_packet, 4);
+
+	if (packet_compression) {
+		buffer_clear(&compression_buffer);
+		buffer_uncompress(&incoming_packet, &compression_buffer);
+		buffer_clear(&incoming_packet);
+		buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
+		    buffer_len(&compression_buffer));
+	}
+	type = buffer_get_char(&incoming_packet);
+	if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
+		packet_disconnect("Invalid ssh1 packet type: %d", type);
+	return type;
+}
+
+static int
+packet_read_poll2(u_int32_t *seqnr_p)
+{
+	static u_int packet_length = 0;
+	u_int padlen, need;
+	u_char *macbuf, *cp, type;
+	u_int maclen, block_size;
+	Enc *enc   = NULL;
+	Mac *mac   = NULL;
+	Comp *comp = NULL;
+
+	if (newkeys[MODE_IN] != NULL) {
+		enc  = &newkeys[MODE_IN]->enc;
+		mac  = &newkeys[MODE_IN]->mac;
+		comp = &newkeys[MODE_IN]->comp;
+	}
+	maclen = mac && mac->enabled ? mac->mac_len : 0;
+	block_size = enc ? enc->block_size : 8;
+
+	if (packet_length == 0) {
+		/*
+		 * check if input size is less than the cipher block size,
+		 * decrypt first block and extract length of incoming packet
+		 */
+		if (buffer_len(&input) < block_size)
+			return SSH_MSG_NONE;
+		buffer_clear(&incoming_packet);
+		cp = buffer_append_space(&incoming_packet, block_size);
+		cipher_crypt(&receive_context, cp, buffer_ptr(&input),
+		    block_size);
+		cp = buffer_ptr(&incoming_packet);
+		packet_length = get_u32(cp);
+		if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
+#ifdef PACKET_DEBUG
+			buffer_dump(&incoming_packet);
+#endif
+			packet_disconnect("Bad packet length %u.", packet_length);
+		}
+		DBG(debug("input: packet len %u", packet_length+4));
+		buffer_consume(&input, block_size);
+	}
+	/* we have a partial packet of block_size bytes */
+	need = 4 + packet_length - block_size;
+	DBG(debug("partial packet %d, need %d, maclen %d", block_size,
+	    need, maclen));
+	if (need % block_size != 0)
+		fatal("padding error: need %d block %d mod %d",
+		    need, block_size, need % block_size);
+	/*
+	 * check if the entire packet has been received and
+	 * decrypt into incoming_packet
+	 */
+	if (buffer_len(&input) < need + maclen)
+		return SSH_MSG_NONE;
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "read_poll enc/full: ");
+	buffer_dump(&input);
+#endif
+	cp = buffer_append_space(&incoming_packet, need);
+	cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
+	buffer_consume(&input, need);
+	/*
+	 * compute MAC over seqnr and packet,
+	 * increment sequence number for incoming packet
+	 */
+	if (mac && mac->enabled) {
+		macbuf = mac_compute(mac, p_read.seqnr,
+		    buffer_ptr(&incoming_packet),
+		    buffer_len(&incoming_packet));
+		if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
+			packet_disconnect("Corrupted MAC on input.");
+		DBG(debug("MAC #%d ok", p_read.seqnr));
+		buffer_consume(&input, mac->mac_len);
+	}
+	if (seqnr_p != NULL)
+		*seqnr_p = p_read.seqnr;
+	if (++p_read.seqnr == 0)
+		logit("incoming seqnr wraps around");
+	if (++p_read.packets == 0)
+		if (!(datafellows & SSH_BUG_NOREKEY))
+			fatal("XXX too many packets with same key");
+	p_read.blocks += (packet_length + 4) / block_size;
+
+	/* get padlen */
+	cp = buffer_ptr(&incoming_packet);
+	padlen = cp[4];
+	DBG(debug("input: padlen %d", padlen));
+	if (padlen < 4)
+		packet_disconnect("Corrupted padlen %d on input.", padlen);
+
+	/* skip packet size + padlen, discard padding */
+	buffer_consume(&incoming_packet, 4 + 1);
+	buffer_consume_end(&incoming_packet, padlen);
+
+	DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
+	if (comp && comp->enabled) {
+		buffer_clear(&compression_buffer);
+		buffer_uncompress(&incoming_packet, &compression_buffer);
+		buffer_clear(&incoming_packet);
+		buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
+		    buffer_len(&compression_buffer));
+		DBG(debug("input: len after de-compress %d",
+		    buffer_len(&incoming_packet)));
+	}
+	/*
+	 * get packet type, implies consume.
+	 * return length of payload (without type field)
+	 */
+	type = buffer_get_char(&incoming_packet);
+	if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
+		packet_disconnect("Invalid ssh2 packet type: %d", type);
+	if (type == SSH2_MSG_NEWKEYS)
+		set_newkeys(MODE_IN);
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
+		packet_enable_delayed_compress();
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "read/plain[%d]:\r\n", type);
+	buffer_dump(&incoming_packet);
+#endif
+	/* reset for next packet */
+	packet_length = 0;
+	return type;
+}
+
+int
+packet_read_poll_seqnr(u_int32_t *seqnr_p)
+{
+	u_int reason, seqnr;
+	u_char type;
+	char *msg;
+
+	for (;;) {
+		if (compat20) {
+			type = packet_read_poll2(seqnr_p);
+			if (type)
+				DBG(debug("received packet type %d", type));
+			switch (type) {
+			case SSH2_MSG_IGNORE:
+				break;
+			case SSH2_MSG_DEBUG:
+				packet_get_char();
+				msg = packet_get_string(NULL);
+				debug("Remote: %.900s", msg);
+				xfree(msg);
+				msg = packet_get_string(NULL);
+				xfree(msg);
+				break;
+			case SSH2_MSG_DISCONNECT:
+				reason = packet_get_int();
+				msg = packet_get_string(NULL);
+				logit("Received disconnect from %s: %u: %.400s",
+				    get_remote_ipaddr(), reason, msg);
+				xfree(msg);
+				cleanup_exit(255);
+				break;
+			case SSH2_MSG_UNIMPLEMENTED:
+				seqnr = packet_get_int();
+				debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
+				    seqnr);
+				break;
+			default:
+				return type;
+			}
+		} else {
+			type = packet_read_poll1();
+			switch (type) {
+			case SSH_MSG_IGNORE:
+				break;
+			case SSH_MSG_DEBUG:
+				msg = packet_get_string(NULL);
+				debug("Remote: %.900s", msg);
+				xfree(msg);
+				break;
+			case SSH_MSG_DISCONNECT:
+				msg = packet_get_string(NULL);
+				logit("Received disconnect from %s: %.400s",
+				    get_remote_ipaddr(), msg);
+				cleanup_exit(255);
+				xfree(msg);
+				break;
+			default:
+				if (type)
+					DBG(debug("received packet type %d", type));
+				return type;
+			}
+		}
+	}
+}
+
+int
+packet_read_poll(void)
+{
+	return packet_read_poll_seqnr(NULL);
+}
+
+/*
+ * Buffers the given amount of input characters.  This is intended to be used
+ * together with packet_read_poll.
+ */
+
+void
+packet_process_incoming(const char *buf, u_int len)
+{
+	buffer_append(&input, buf, len);
+}
+
+/* Returns a character from the packet. */
+
+u_int
+packet_get_char(void)
+{
+	char ch;
+
+	buffer_get(&incoming_packet, &ch, 1);
+	return (u_char) ch;
+}
+
+/* Returns an integer from the packet data. */
+
+u_int
+packet_get_int(void)
+{
+	return buffer_get_int(&incoming_packet);
+}
+
+/*
+ * Returns an arbitrary precision integer from the packet data.  The integer
+ * must have been initialized before this call.
+ */
+
+void
+packet_get_bignum(BIGNUM * value)
+{
+	buffer_get_bignum(&incoming_packet, value);
+}
+
+void
+packet_get_bignum2(BIGNUM * value)
+{
+	buffer_get_bignum2(&incoming_packet, value);
+}
+
+void *
+packet_get_raw(u_int *length_ptr)
+{
+	u_int bytes = buffer_len(&incoming_packet);
+
+	if (length_ptr != NULL)
+		*length_ptr = bytes;
+	return buffer_ptr(&incoming_packet);
+}
+
+int
+packet_remaining(void)
+{
+	return buffer_len(&incoming_packet);
+}
+
+/*
+ * Returns a string from the packet data.  The string is allocated using
+ * xmalloc; it is the responsibility of the calling program to free it when
+ * no longer needed.  The length_ptr argument may be NULL, or point to an
+ * integer into which the length of the string is stored.
+ */
+
+void *
+packet_get_string(u_int *length_ptr)
+{
+	return buffer_get_string(&incoming_packet, length_ptr);
+}
+
+/*
+ * Sends a diagnostic message from the server to the client.  This message
+ * can be sent at any time (but not while constructing another message). The
+ * message is printed immediately, but only if the client is being executed
+ * in verbose mode.  These messages are primarily intended to ease debugging
+ * authentication problems.   The length of the formatted message must not
+ * exceed 1024 bytes.  This will automatically call packet_write_wait.
+ */
+
+void
+packet_send_debug(const char *fmt,...)
+{
+	char buf[1024];
+	va_list args;
+
+	if (compat20 && (datafellows & SSH_BUG_DEBUG))
+		return;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	if (compat20) {
+		packet_start(SSH2_MSG_DEBUG);
+		packet_put_char(0);	/* bool: always display */
+		packet_put_cstring(buf);
+		packet_put_cstring("");
+	} else {
+		packet_start(SSH_MSG_DEBUG);
+		packet_put_cstring(buf);
+	}
+	packet_send();
+	packet_write_wait();
+}
+
+/*
+ * Logs the error plus constructs and sends a disconnect packet, closes the
+ * connection, and exits.  This function never returns. The error message
+ * should not contain a newline.  The length of the formatted message must
+ * not exceed 1024 bytes.
+ */
+
+void
+packet_disconnect(const char *fmt,...)
+{
+	char buf[1024];
+	va_list args;
+	static int disconnecting = 0;
+
+	if (disconnecting)	/* Guard against recursive invocations. */
+		fatal("packet_disconnect called recursively.");
+	disconnecting = 1;
+
+	/*
+	 * Format the message.  Note that the caller must make sure the
+	 * message is of limited size.
+	 */
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	/* Display the error locally */
+	logit("Disconnecting: %.100s", buf);
+
+	/* Send the disconnect message to the other side, and wait for it to get sent. */
+	if (compat20) {
+		packet_start(SSH2_MSG_DISCONNECT);
+		packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
+		packet_put_cstring(buf);
+		packet_put_cstring("");
+	} else {
+		packet_start(SSH_MSG_DISCONNECT);
+		packet_put_cstring(buf);
+	}
+	packet_send();
+	packet_write_wait();
+
+	/* Stop listening for connections. */
+	channel_close_all();
+
+	/* Close the connection. */
+	packet_close();
+	cleanup_exit(255);
+}
+
+/* Checks if there is any buffered output, and tries to write some of the output. */
+
+void
+packet_write_poll(void)
+{
+	int len = buffer_len(&output);
+
+	if (len > 0) {
+		len = write(connection_out, buffer_ptr(&output), len);
+		if (len <= 0) {
+			if (errno == EAGAIN)
+				return;
+			else
+				fatal("Write failed: %.100s", strerror(errno));
+		}
+		buffer_consume(&output, len);
+	}
+}
+
+/*
+ * Calls packet_write_poll repeatedly until all pending output data has been
+ * written.
+ */
+
+void
+packet_write_wait(void)
+{
+	fd_set *setp;
+
+	setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS),
+	    sizeof(fd_mask));
+	packet_write_poll();
+	while (packet_have_data_to_write()) {
+		memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
+		    sizeof(fd_mask));
+		FD_SET(connection_out, setp);
+		while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
+		    (errno == EAGAIN || errno == EINTR))
+			;
+		packet_write_poll();
+	}
+	xfree(setp);
+}
+
+/* Returns true if there is buffered data to write to the connection. */
+
+int
+packet_have_data_to_write(void)
+{
+	return buffer_len(&output) != 0;
+}
+
+/* Returns true if there is not too much data to write to the connection. */
+
+int
+packet_not_very_much_data_to_write(void)
+{
+	if (interactive_mode)
+		return buffer_len(&output) < 16384;
+	else
+		return buffer_len(&output) < 128 * 1024;
+}
+
+
+static void
+packet_set_tos(int interactive)
+{
+#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
+	int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
+
+	if (!packet_connection_is_on_socket() ||
+	    !packet_connection_is_ipv4())
+		return;
+	if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
+	    sizeof(tos)) < 0)
+		error("setsockopt IP_TOS %d: %.100s:",
+		    tos, strerror(errno));
+#endif
+}
+
+/* Informs that the current session is interactive.  Sets IP flags for that. */
+
+void
+packet_set_interactive(int interactive)
+{
+	static int called = 0;
+
+	if (called)
+		return;
+	called = 1;
+
+	/* Record that we are in interactive mode. */
+	interactive_mode = interactive;
+
+	/* Only set socket options if using a socket.  */
+	if (!packet_connection_is_on_socket())
+		return;
+	set_nodelay(connection_in);
+	packet_set_tos(interactive);
+}
+
+/* Returns true if the current connection is interactive. */
+
+int
+packet_is_interactive(void)
+{
+	return interactive_mode;
+}
+
+int
+packet_set_maxsize(u_int s)
+{
+	static int called = 0;
+
+	if (called) {
+		logit("packet_set_maxsize: called twice: old %d new %d",
+		    max_packet_size, s);
+		return -1;
+	}
+	if (s < 4 * 1024 || s > 1024 * 1024) {
+		logit("packet_set_maxsize: bad size %d", s);
+		return -1;
+	}
+	called = 1;
+	debug("packet_set_maxsize: setting to %d", s);
+	max_packet_size = s;
+	return s;
+}
+
+/* roundup current message to pad bytes */
+void
+packet_add_padding(u_char pad)
+{
+	extra_pad = pad;
+}
+
+/*
+ * 9.2.  Ignored Data Message
+ *
+ *   byte      SSH_MSG_IGNORE
+ *   string    data
+ *
+ * All implementations MUST understand (and ignore) this message at any
+ * time (after receiving the protocol version). No implementation is
+ * required to send them. This message can be used as an additional
+ * protection measure against advanced traffic analysis techniques.
+ */
+void
+packet_send_ignore(int nbytes)
+{
+	u_int32_t rnd = 0;
+	int i;
+
+	packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
+	packet_put_int(nbytes);
+	for (i = 0; i < nbytes; i++) {
+		if (i % 4 == 0)
+			rnd = arc4random();
+		packet_put_char((u_char)rnd & 0xff);
+		rnd >>= 8;
+	}
+}
+
+#define MAX_PACKETS	(1U<<31)
+int
+packet_need_rekeying(void)
+{
+	if (datafellows & SSH_BUG_NOREKEY)
+		return 0;
+	return
+	    (p_send.packets > MAX_PACKETS) ||
+	    (p_read.packets > MAX_PACKETS) ||
+	    (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
+	    (max_blocks_in  && (p_read.blocks > max_blocks_in));
+}
+
+void
+packet_set_rekey_limit(u_int32_t bytes)
+{
+	rekey_limit = bytes;
+}
+
+void
+packet_set_server(void)
+{
+	server_side = 1;
+}
+
+void
+packet_set_authenticated(void)
+{
+	after_authentication = 1;
+}