upstream commit

update packet.c & isolate, introduce struct ssh a) switch
 packet.c to buffer api and isolate per-connection info into struct ssh b)
 (de)serialization of the state is moved from monitor to packet.c c) the old
 packet.c API is implemented in opacket.[ch] d) compress.c/h is removed and
 integrated into packet.c with and ok djm@
diff --git a/packet.c b/packet.c
index d6f9ff3..3306e4d 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.200 2015/01/13 19:31:40 markus Exp $ */
+/* $OpenBSD: packet.c,v 1.201 2015/01/19 19:52:16 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -60,17 +60,19 @@
 #include <signal.h>
 #include <time.h>
 
+#include <zlib.h>
+
+#include "buffer.h"	/* typedefs XXX */
+#include "key.h"	/* typedefs XXX */
+
 #include "xmalloc.h"
-#include "buffer.h"
-#include "packet.h"
 #include "crc32.h"
-#include "compress.h"
 #include "deattack.h"
 #include "compat.h"
 #include "ssh1.h"
 #include "ssh2.h"
 #include "cipher.h"
-#include "key.h"
+#include "sshkey.h"
 #include "kex.h"
 #include "digest.h"
 #include "mac.h"
@@ -79,8 +81,10 @@
 #include "misc.h"
 #include "channels.h"
 #include "ssh.h"
-#include "ssherr.h"
+#include "packet.h"
 #include "roaming.h"
+#include "ssherr.h"
+#include "sshbuf.h"
 
 #ifdef PACKET_DEBUG
 #define DBG(x) x
@@ -100,7 +104,7 @@
 struct packet {
 	TAILQ_ENTRY(packet) next;
 	u_char type;
-	Buffer payload;
+	struct sshbuf *payload;
 };
 
 struct session_state {
@@ -117,26 +121,33 @@
 	u_int remote_protocol_flags;
 
 	/* Encryption context for receiving data.  Only used for decryption. */
-	CipherContext receive_context;
+	struct sshcipher_ctx receive_context;
 
 	/* Encryption context for sending data.  Only used for encryption. */
-	CipherContext send_context;
+	struct sshcipher_ctx send_context;
 
 	/* Buffer for raw input data from the socket. */
-	Buffer input;
+	struct sshbuf *input;
 
 	/* Buffer for raw output data going to the socket. */
-	Buffer output;
+	struct sshbuf *output;
 
 	/* Buffer for the partial outgoing packet being constructed. */
-	Buffer outgoing_packet;
+	struct sshbuf *outgoing_packet;
 
 	/* Buffer for the incoming packet currently being processed. */
-	Buffer incoming_packet;
+	struct sshbuf *incoming_packet;
 
 	/* Scratch buffer for packet compression/decompression. */
-	Buffer compression_buffer;
-	int compression_buffer_ready;
+	struct sshbuf *compression_buffer;
+
+	/* Incoming/outgoing compression dictionaries */
+	z_stream compression_in_stream;
+	z_stream compression_out_stream;
+	int compression_in_started;
+	int compression_out_started;
+	int compression_in_failures;
+	int compression_out_failures;
 
 	/*
 	 * Flag indicating whether packet compression/decompression is
@@ -165,7 +176,7 @@
 	int packet_timeout_ms;
 
 	/* Session key information for Encryption and MAC */
-	Newkeys *newkeys[MODE_MAX];
+	struct newkeys *newkeys[MODE_MAX];
 	struct packet_state p_read, p_send;
 
 	/* Volume-based rekeying */
@@ -185,7 +196,7 @@
 
 	/* XXX discard incoming data after MAC error */
 	u_int packet_discard;
-	Mac *packet_discard_mac;
+	struct sshmac *packet_discard_mac;
 
 	/* Used in packet_read_poll2() */
 	u_int packlen;
@@ -199,121 +210,164 @@
 	/* Used in packet_set_maxsize */
 	int set_maxsize_called;
 
+	/* One-off warning about weak ciphers */
+	int cipher_warning_done;
+
+	/* SSH1 CRC compensation attack detector */
+	struct deattack_ctx deattack;
+
 	TAILQ_HEAD(, packet) outgoing;
 };
 
-static struct session_state *active_state, *backup_state;
-
-static struct session_state *
-alloc_session_state(void)
+struct ssh *
+ssh_alloc_session_state(void)
 {
-	struct session_state *s = xcalloc(1, sizeof(*s));
+	struct ssh *ssh = NULL;
+	struct session_state *state = NULL;
 
-	s->connection_in = -1;
-	s->connection_out = -1;
-	s->max_packet_size = 32768;
-	s->packet_timeout_ms = -1;
-	return s;
+	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
+	    (state = calloc(1, sizeof(*state))) == NULL ||
+	    (state->input = sshbuf_new()) == NULL ||
+	    (state->output = sshbuf_new()) == NULL ||
+	    (state->outgoing_packet = sshbuf_new()) == NULL ||
+	    (state->incoming_packet = sshbuf_new()) == NULL)
+		goto fail;
+	TAILQ_INIT(&state->outgoing);
+	state->connection_in = -1;
+	state->connection_out = -1;
+	state->max_packet_size = 32768;
+	state->packet_timeout_ms = -1;
+	state->p_send.packets = state->p_read.packets = 0;
+	state->initialized = 1;
+	/*
+	 * ssh_packet_send2() needs to queue packets until
+	 * we've done the initial key exchange.
+	 */
+	state->rekeying = 1;
+	ssh->state = state;
+	return ssh;
+ fail:
+	if (state) {
+		sshbuf_free(state->input);
+		sshbuf_free(state->output);
+		sshbuf_free(state->incoming_packet);
+		sshbuf_free(state->outgoing_packet);
+		free(state);
+	}
+	free(ssh);
+	return NULL;
 }
 
 /*
  * 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)
+struct ssh *
+ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
 {
-	const Cipher *none = cipher_by_name("none");
+	struct session_state *state;
+	const struct sshcipher *none = cipher_by_name("none");
 	int r;
 
 	if (none == NULL)
-		fatal("packet_set_connection: cannot load cipher 'none'");
-	if (active_state == NULL)
-		active_state = alloc_session_state();
-	active_state->connection_in = fd_in;
-	active_state->connection_out = fd_out;
-	if ((r = cipher_init(&active_state->send_context, none,
+		fatal("%s: cannot load cipher 'none'", __func__);
+	if (ssh == NULL)
+		ssh = ssh_alloc_session_state();
+	if (ssh == NULL)
+		fatal("%s: cound not allocate state", __func__);
+	state = ssh->state;
+	state->connection_in = fd_in;
+	state->connection_out = fd_out;
+	if ((r = cipher_init(&state->send_context, none,
 	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
-	    (r = cipher_init(&active_state->receive_context, none,
+	    (r = cipher_init(&state->receive_context, none,
 	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0)
-		fatal("%s: cipher_init: %s", __func__, ssh_err(r));
-	active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL;
-	if (!active_state->initialized) {
-		active_state->initialized = 1;
-		buffer_init(&active_state->input);
-		buffer_init(&active_state->output);
-		buffer_init(&active_state->outgoing_packet);
-		buffer_init(&active_state->incoming_packet);
-		TAILQ_INIT(&active_state->outgoing);
-		active_state->p_send.packets = active_state->p_read.packets = 0;
-	}
+		fatal("%s: cipher_init failed: %s", __func__, ssh_err(r));
+	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
+	deattack_init(&state->deattack);
+	return ssh;
 }
 
 void
-packet_set_timeout(int timeout, int count)
+ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
 {
+	struct session_state *state = ssh->state;
+
 	if (timeout <= 0 || count <= 0) {
-		active_state->packet_timeout_ms = -1;
+		state->packet_timeout_ms = -1;
 		return;
 	}
 	if ((INT_MAX / 1000) / count < timeout)
-		active_state->packet_timeout_ms = INT_MAX;
+		state->packet_timeout_ms = INT_MAX;
 	else
-		active_state->packet_timeout_ms = timeout * count * 1000;
+		state->packet_timeout_ms = timeout * count * 1000;
 }
 
-static void
-packet_stop_discard(void)
+int
+ssh_packet_stop_discard(struct ssh *ssh)
 {
-	if (active_state->packet_discard_mac) {
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (state->packet_discard_mac) {
 		char buf[1024];
-		
+
 		memset(buf, 'a', sizeof(buf));
-		while (buffer_len(&active_state->incoming_packet) <
+		while (sshbuf_len(state->incoming_packet) <
 		    PACKET_MAX_SIZE)
-			buffer_append(&active_state->incoming_packet, buf,
-			    sizeof(buf));
-		(void) mac_compute(active_state->packet_discard_mac,
-		    active_state->p_read.seqnr,
-		    buffer_ptr(&active_state->incoming_packet),
-		    PACKET_MAX_SIZE, NULL, 0);
+			if ((r = sshbuf_put(state->incoming_packet, buf,
+			    sizeof(buf))) != 0)
+				return r;
+		(void) mac_compute(state->packet_discard_mac,
+		    state->p_read.seqnr,
+		    sshbuf_ptr(state->incoming_packet), PACKET_MAX_SIZE,
+		    NULL, 0);
 	}
-	logit("Finished discarding for %.200s", get_remote_ipaddr());
-	cleanup_exit(255);
+	logit("Finished discarding for %.200s", ssh_remote_ipaddr(ssh));
+	return SSH_ERR_MAC_INVALID;
 }
 
-static void
-packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard)
+static int
+ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
+    struct sshmac *mac, u_int packet_length, u_int discard)
 {
-	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm))
-		packet_disconnect("Packet corrupt");
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
+		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
+			return r;
+		return SSH_ERR_MAC_INVALID;
+	}
 	if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled)
-		active_state->packet_discard_mac = mac;
-	if (buffer_len(&active_state->input) >= discard)
-		packet_stop_discard();
-	active_state->packet_discard = discard -
-	    buffer_len(&active_state->input);
+		state->packet_discard_mac = mac;
+	if (sshbuf_len(state->input) >= discard &&
+	   (r = ssh_packet_stop_discard(ssh)) != 0)
+		return r;
+	state->packet_discard = discard - sshbuf_len(state->input);
+	return 0;
 }
 
 /* Returns 1 if remote host is connected via socket, 0 if not. */
 
 int
-packet_connection_is_on_socket(void)
+ssh_packet_connection_is_on_socket(struct ssh *ssh)
 {
+	struct session_state *state = ssh->state;
 	struct sockaddr_storage from, to;
 	socklen_t fromlen, tolen;
 
 	/* filedescriptors in and out are the same, so it's a socket */
-	if (active_state->connection_in == active_state->connection_out)
+	if (state->connection_in == state->connection_out)
 		return 1;
 	fromlen = sizeof(from);
 	memset(&from, 0, sizeof(from));
-	if (getpeername(active_state->connection_in, (struct sockaddr *)&from,
+	if (getpeername(state->connection_in, (struct sockaddr *)&from,
 	    &fromlen) < 0)
 		return 0;
 	tolen = sizeof(to);
 	memset(&to, 0, sizeof(to));
-	if (getpeername(active_state->connection_out, (struct sockaddr *)&to,
+	if (getpeername(state->connection_out, (struct sockaddr *)&to,
 	    &tolen) < 0)
 		return 0;
 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
@@ -323,127 +377,23 @@
 	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)
+ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
 {
-	CipherContext *cc;
-	int r;
-
-	if (mode == MODE_OUT)
-		cc = &active_state->send_context;
-	else
-		cc = &active_state->receive_context;
-
-	if ((r = cipher_get_keyiv(cc, iv, len)) != 0)
-		fatal("%s: cipher_get_keyiv: %s", __func__, ssh_err(r));
+	if (ibytes)
+		*ibytes = ssh->state->p_read.bytes;
+	if (obytes)
+		*obytes = ssh->state->p_send.bytes;
 }
 
 int
-packet_get_keycontext(int mode, u_char *dat)
-{
-	CipherContext *cc;
-
-	if (mode == MODE_OUT)
-		cc = &active_state->send_context;
-	else
-		cc = &active_state->receive_context;
-
-	return (cipher_get_keycontext(cc, dat));
-}
-
-void
-packet_set_keycontext(int mode, u_char *dat)
-{
-	CipherContext *cc;
-
-	if (mode == MODE_OUT)
-		cc = &active_state->send_context;
-	else
-		cc = &active_state->receive_context;
-
-	cipher_set_keycontext(cc, dat);
-}
-
-int
-packet_get_keyiv_len(int mode)
-{
-	CipherContext *cc;
-
-	if (mode == MODE_OUT)
-		cc = &active_state->send_context;
-	else
-		cc = &active_state->receive_context;
-
-	return (cipher_get_keyiv_len(cc));
-}
-
-void
-packet_set_iv(int mode, u_char *dat)
-{
-	CipherContext *cc;
-	int r;
-
-	if (mode == MODE_OUT)
-		cc = &active_state->send_context;
-	else
-		cc = &active_state->receive_context;
-
-	if ((r = cipher_set_keyiv(cc, dat)) != 0)
-		fatal("%s: cipher_set_keyiv: %s", __func__, ssh_err(r));
-}
-
-int
-packet_get_ssh1_cipher(void)
-{
-	return (cipher_get_number(active_state->receive_context.cipher));
-}
-
-void
-packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks,
-    u_int32_t *packets, u_int64_t *bytes)
-{
-	struct packet_state *state;
-
-	state = (mode == MODE_IN) ?
-	    &active_state->p_read : &active_state->p_send;
-	if (seqnr)
-		*seqnr = state->seqnr;
-	if (blocks)
-		*blocks = state->blocks;
-	if (packets)
-		*packets = state->packets;
-	if (bytes)
-		*bytes = state->bytes;
-}
-
-void
-packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets,
-    u_int64_t bytes)
-{
-	struct packet_state *state;
-
-	state = (mode == MODE_IN) ?
-	    &active_state->p_read : &active_state->p_send;
-	state->seqnr = seqnr;
-	state->blocks = blocks;
-	state->packets = packets;
-	state->bytes = bytes;
-}
-
-static int
-packet_connection_af(void)
+ssh_packet_connection_af(struct ssh *ssh)
 {
 	struct sockaddr_storage to;
 	socklen_t tolen = sizeof(to);
 
 	memset(&to, 0, sizeof(to));
-	if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
+	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
 	    &tolen) < 0)
 		return 0;
 #ifdef IPV4_IN_IPV6
@@ -457,72 +407,125 @@
 /* Sets the connection into non-blocking mode. */
 
 void
-packet_set_nonblocking(void)
+ssh_packet_set_nonblocking(struct ssh *ssh)
 {
 	/* Set the socket into non-blocking mode. */
-	set_nonblock(active_state->connection_in);
+	set_nonblock(ssh->state->connection_in);
 
-	if (active_state->connection_out != active_state->connection_in)
-		set_nonblock(active_state->connection_out);
+	if (ssh->state->connection_out != ssh->state->connection_in)
+		set_nonblock(ssh->state->connection_out);
 }
 
 /* Returns the socket used for reading. */
 
 int
-packet_get_connection_in(void)
+ssh_packet_get_connection_in(struct ssh *ssh)
 {
-	return active_state->connection_in;
+	return ssh->state->connection_in;
 }
 
 /* Returns the descriptor used for writing. */
 
 int
-packet_get_connection_out(void)
+ssh_packet_get_connection_out(struct ssh *ssh)
 {
-	return active_state->connection_out;
+	return ssh->state->connection_out;
+}
+
+/*
+ * Returns the IP-address of the remote host as a string.  The returned
+ * string must not be freed.
+ */
+
+const char *
+ssh_remote_ipaddr(struct ssh *ssh)
+{
+	/* Check whether we have cached the ipaddr. */
+	if (ssh->remote_ipaddr == NULL)
+		ssh->remote_ipaddr = ssh_packet_connection_is_on_socket(ssh) ?
+		    get_peer_ipaddr(ssh->state->connection_in) :
+		    strdup("UNKNOWN");
+	if (ssh->remote_ipaddr == NULL)
+		return "UNKNOWN";
+	return ssh->remote_ipaddr;
 }
 
 /* Closes the connection and clears and frees internal data structures. */
 
 void
-packet_close(void)
+ssh_packet_close(struct ssh *ssh)
 {
-	if (!active_state->initialized)
+	struct session_state *state = ssh->state;
+	int r;
+	u_int mode;
+
+	if (!state->initialized)
 		return;
-	active_state->initialized = 0;
-	if (active_state->connection_in == active_state->connection_out) {
-		shutdown(active_state->connection_out, SHUT_RDWR);
-		close(active_state->connection_out);
+	state->initialized = 0;
+	if (state->connection_in == state->connection_out) {
+		shutdown(state->connection_out, SHUT_RDWR);
+		close(state->connection_out);
 	} else {
-		close(active_state->connection_in);
-		close(active_state->connection_out);
+		close(state->connection_in);
+		close(state->connection_out);
 	}
-	buffer_free(&active_state->input);
-	buffer_free(&active_state->output);
-	buffer_free(&active_state->outgoing_packet);
-	buffer_free(&active_state->incoming_packet);
-	if (active_state->compression_buffer_ready) {
-		buffer_free(&active_state->compression_buffer);
-		buffer_compress_uninit();
+	sshbuf_free(state->input);
+	sshbuf_free(state->output);
+	sshbuf_free(state->outgoing_packet);
+	sshbuf_free(state->incoming_packet);
+	for (mode = 0; mode < MODE_MAX; mode++)
+		kex_free_newkeys(state->newkeys[mode]);
+	if (state->compression_buffer) {
+		sshbuf_free(state->compression_buffer);
+		if (state->compression_out_started) {
+			z_streamp stream = &state->compression_out_stream;
+			debug("compress outgoing: "
+			    "raw data %llu, compressed %llu, factor %.2f",
+				(unsigned long long)stream->total_in,
+				(unsigned long long)stream->total_out,
+				stream->total_in == 0 ? 0.0 :
+				(double) stream->total_out / stream->total_in);
+			if (state->compression_out_failures == 0)
+				deflateEnd(stream);
+		}
+		if (state->compression_in_started) {
+			z_streamp stream = &state->compression_out_stream;
+			debug("compress incoming: "
+			    "raw data %llu, compressed %llu, factor %.2f",
+			    (unsigned long long)stream->total_out,
+			    (unsigned long long)stream->total_in,
+			    stream->total_out == 0 ? 0.0 :
+			    (double) stream->total_in / stream->total_out);
+			if (state->compression_in_failures == 0)
+				inflateEnd(stream);
+		}
 	}
-	cipher_cleanup(&active_state->send_context);
-	cipher_cleanup(&active_state->receive_context);
+	if ((r = cipher_cleanup(&state->send_context)) != 0)
+		error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r));
+	if ((r = cipher_cleanup(&state->receive_context)) != 0)
+		error("%s: cipher_cleanup failed: %s", __func__, ssh_err(r));
+	if (ssh->remote_ipaddr) {
+		free(ssh->remote_ipaddr);
+		ssh->remote_ipaddr = NULL;
+	}
+	free(ssh->state);
+	ssh->state = NULL;
 }
 
 /* Sets remote side protocol flags. */
 
 void
-packet_set_protocol_flags(u_int protocol_flags)
+ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
 {
-	active_state->remote_protocol_flags = protocol_flags;
+	ssh->state->remote_protocol_flags = protocol_flags;
 }
 
 /* Returns the remote protocol flags set earlier by the above function. */
 
 u_int
-packet_get_protocol_flags(void)
+ssh_packet_get_protocol_flags(struct ssh *ssh)
 {
-	return active_state->remote_protocol_flags;
+	return ssh->state->remote_protocol_flags;
 }
 
 /*
@@ -530,24 +533,239 @@
  * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
  */
 
-static void
-packet_init_compression(void)
+static int
+ssh_packet_init_compression(struct ssh *ssh)
 {
-	if (active_state->compression_buffer_ready == 1)
-		return;
-	active_state->compression_buffer_ready = 1;
-	buffer_init(&active_state->compression_buffer);
+	if (!ssh->state->compression_buffer &&
+	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
+		return SSH_ERR_ALLOC_FAIL;
+	return 0;
+}
+
+static int
+start_compression_out(struct ssh *ssh, int level)
+{
+	if (level < 1 || level > 9)
+		return SSH_ERR_INVALID_ARGUMENT;
+	debug("Enabling compression at level %d.", level);
+	if (ssh->state->compression_out_started == 1)
+		deflateEnd(&ssh->state->compression_out_stream);
+	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
+	case Z_OK:
+		ssh->state->compression_out_started = 1;
+		break;
+	case Z_MEM_ERROR:
+		return SSH_ERR_ALLOC_FAIL;
+	default:
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}
+
+static int
+start_compression_in(struct ssh *ssh)
+{
+	if (ssh->state->compression_in_started == 1)
+		inflateEnd(&ssh->state->compression_in_stream);
+	switch (inflateInit(&ssh->state->compression_in_stream)) {
+	case Z_OK:
+		ssh->state->compression_in_started = 1;
+		break;
+	case Z_MEM_ERROR:
+		return SSH_ERR_ALLOC_FAIL;
+	default:
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}
+
+int
+ssh_packet_start_compression(struct ssh *ssh, int level)
+{
+	int r;
+
+	if (ssh->state->packet_compression && !compat20)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->state->packet_compression = 1;
+	if ((r = ssh_packet_init_compression(ssh)) != 0 ||
+	    (r = start_compression_in(ssh)) != 0 ||
+	    (r = start_compression_out(ssh, level)) != 0)
+		return r;
+	return 0;
+}
+
+/* XXX remove need for separate compression buffer */
+static int
+compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+	u_char buf[4096];
+	int r, status;
+
+	if (ssh->state->compression_out_started != 1)
+		return SSH_ERR_INTERNAL_ERROR;
+
+	/* This case is not handled below. */
+	if (sshbuf_len(in) == 0)
+		return 0;
+
+	/* Input is the contents of the input buffer. */
+	if ((ssh->state->compression_out_stream.next_in =
+	    sshbuf_mutable_ptr(in)) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
+
+	/* Loop compressing until deflate() returns with avail_out != 0. */
+	do {
+		/* Set up fixed-size output buffer. */
+		ssh->state->compression_out_stream.next_out = buf;
+		ssh->state->compression_out_stream.avail_out = sizeof(buf);
+
+		/* Compress as much data into the buffer as possible. */
+		status = deflate(&ssh->state->compression_out_stream,
+		    Z_PARTIAL_FLUSH);
+		switch (status) {
+		case Z_MEM_ERROR:
+			return SSH_ERR_ALLOC_FAIL;
+		case Z_OK:
+			/* Append compressed data to output_buffer. */
+			if ((r = sshbuf_put(out, buf, sizeof(buf) -
+			    ssh->state->compression_out_stream.avail_out)) != 0)
+				return r;
+			break;
+		case Z_STREAM_ERROR:
+		default:
+			ssh->state->compression_out_failures++;
+			return SSH_ERR_INVALID_FORMAT;
+		}
+	} while (ssh->state->compression_out_stream.avail_out == 0);
+	return 0;
+}
+
+static int
+uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+	u_char buf[4096];
+	int r, status;
+
+	if (ssh->state->compression_in_started != 1)
+		return SSH_ERR_INTERNAL_ERROR;
+
+	if ((ssh->state->compression_in_stream.next_in =
+	    sshbuf_mutable_ptr(in)) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
+
+	for (;;) {
+		/* Set up fixed-size output buffer. */
+		ssh->state->compression_in_stream.next_out = buf;
+		ssh->state->compression_in_stream.avail_out = sizeof(buf);
+
+		status = inflate(&ssh->state->compression_in_stream,
+		    Z_PARTIAL_FLUSH);
+		switch (status) {
+		case Z_OK:
+			if ((r = sshbuf_put(out, buf, sizeof(buf) -
+			    ssh->state->compression_in_stream.avail_out)) != 0)
+				return r;
+			break;
+		case Z_BUF_ERROR:
+			/*
+			 * Comments in zlib.h say that we should keep calling
+			 * inflate() until we get an error.  This appears to
+			 * be the error that we get.
+			 */
+			return 0;
+		case Z_DATA_ERROR:
+			return SSH_ERR_INVALID_FORMAT;
+		case Z_MEM_ERROR:
+			return SSH_ERR_ALLOC_FAIL;
+		case Z_STREAM_ERROR:
+		default:
+			ssh->state->compression_in_failures++;
+			return SSH_ERR_INTERNAL_ERROR;
+		}
+	}
+	/* NOTREACHED */
+}
+
+/* Serialise compression state into a blob for privsep */
+static int
+ssh_packet_get_compress_state(struct sshbuf *m, struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	struct sshbuf *b;
+	int r;
+
+	if ((b = sshbuf_new()) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	if (state->compression_in_started) {
+		if ((r = sshbuf_put_string(b, &state->compression_in_stream,
+		    sizeof(state->compression_in_stream))) != 0)
+			goto out;
+	} else if ((r = sshbuf_put_string(b, NULL, 0)) != 0)
+		goto out;
+	if (state->compression_out_started) {
+		if ((r = sshbuf_put_string(b, &state->compression_out_stream,
+		    sizeof(state->compression_out_stream))) != 0)
+			goto out;
+	} else if ((r = sshbuf_put_string(b, NULL, 0)) != 0)
+		goto out;
+	r = sshbuf_put_stringb(m, b);
+ out:
+	sshbuf_free(b);
+	return r;
+}
+
+/* Deserialise compression state from a blob for privsep */
+static int
+ssh_packet_set_compress_state(struct ssh *ssh, struct sshbuf *m)
+{
+	struct session_state *state = ssh->state;
+	struct sshbuf *b = NULL;
+	int r;
+	const u_char *inblob, *outblob;
+	size_t inl, outl;
+
+	if ((r = sshbuf_froms(m, &b)) != 0)
+		goto out;
+	if ((r = sshbuf_get_string_direct(b, &inblob, &inl)) != 0 ||
+	    (r = sshbuf_get_string_direct(b, &outblob, &outl)) != 0)
+		goto out;
+	if (inl == 0)
+		state->compression_in_started = 0;
+	else if (inl != sizeof(state->compression_in_stream)) {
+		r = SSH_ERR_INTERNAL_ERROR;
+		goto out;
+	} else {
+		state->compression_in_started = 1;
+		memcpy(&state->compression_in_stream, inblob, inl);
+	}
+	if (outl == 0)
+		state->compression_out_started = 0;
+	else if (outl != sizeof(state->compression_out_stream)) {
+		r = SSH_ERR_INTERNAL_ERROR;
+		goto out;
+	} else {
+		state->compression_out_started = 1;
+		memcpy(&state->compression_out_stream, outblob, outl);
+	}
+	r = 0;
+ out:
+	sshbuf_free(b);
+	return r;
 }
 
 void
-packet_start_compression(int level)
+ssh_packet_set_compress_hooks(struct ssh *ssh, void *ctx,
+    void *(*allocfunc)(void *, u_int, u_int),
+    void (*freefunc)(void *, void *))
 {
-	if (active_state->packet_compression && !compat20)
-		fatal("Compression already enabled.");
-	active_state->packet_compression = 1;
-	packet_init_compression();
-	buffer_compress_init_send(level);
-	buffer_compress_init_recv();
+	ssh->state->compression_out_stream.zalloc = (alloc_func)allocfunc;
+	ssh->state->compression_out_stream.zfree = (free_func)freefunc;
+	ssh->state->compression_out_stream.opaque = ctx;
+	ssh->state->compression_in_stream.zalloc = (alloc_func)allocfunc;
+	ssh->state->compression_in_stream.zfree = (free_func)freefunc;
+	ssh->state->compression_in_stream.opaque = ctx;
 }
 
 /*
@@ -556,109 +774,34 @@
  * encrypted independently of each other.
  */
 
-void
-packet_set_encryption_key(const u_char *key, u_int keylen, int number)
-{
-	const Cipher *cipher = cipher_by_number(number);
-	int r;
-
-	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(active_state->ssh1_key, key, keylen);
-	active_state->ssh1_keylen = keylen;
-	if ((r = cipher_init(&active_state->send_context, cipher,
-	    key, keylen, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
-	    (r = cipher_init(&active_state->receive_context, cipher,
-	    key, keylen, NULL, 0, CIPHER_DECRYPT)) != 0)
-		fatal("%s: cipher_init: %s", __func__, ssh_err(r));
-}
-
-u_int
-packet_get_encryption_key(u_char *key)
-{
-	if (key == NULL)
-		return (active_state->ssh1_keylen);
-	memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
-	return (active_state->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(&active_state->outgoing_packet);
-	buffer_append(&active_state->outgoing_packet, buf, len);
-}
-
-/* Append payload. */
-void
-packet_put_char(int value)
-{
-	char ch = value;
-
-	buffer_append(&active_state->outgoing_packet, &ch, 1);
-}
-
-void
-packet_put_int(u_int value)
-{
-	buffer_put_int(&active_state->outgoing_packet, value);
-}
-
-void
-packet_put_int64(u_int64_t value)
-{
-	buffer_put_int64(&active_state->outgoing_packet, value);
-}
-
-void
-packet_put_string(const void *buf, u_int len)
-{
-	buffer_put_string(&active_state->outgoing_packet, buf, len);
-}
-
-void
-packet_put_cstring(const char *str)
-{
-	buffer_put_cstring(&active_state->outgoing_packet, str);
-}
-
-void
-packet_put_raw(const void *buf, u_int len)
-{
-	buffer_append(&active_state->outgoing_packet, buf, len);
-}
-
 #ifdef WITH_OPENSSL
 void
-packet_put_bignum(BIGNUM * value)
+ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number)
 {
-	buffer_put_bignum(&active_state->outgoing_packet, value);
-}
+	struct session_state *state = ssh->state;
+	const struct sshcipher *cipher = cipher_by_number(number);
+	int r;
+	const char *wmsg;
 
-void
-packet_put_bignum2(BIGNUM * value)
-{
-	buffer_put_bignum2(&active_state->outgoing_packet, value);
-}
-#endif
-
-#ifdef OPENSSL_HAS_ECC
-void
-packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point)
-{
-	buffer_put_ecpoint(&active_state->outgoing_packet, curve, point);
+	if (cipher == NULL)
+		fatal("%s: unknown cipher number %d", __func__, number);
+	if (keylen < 20)
+		fatal("%s: keylen too small: %d", __func__, keylen);
+	if (keylen > SSH_SESSION_KEY_LENGTH)
+		fatal("%s: keylen too big: %d", __func__, keylen);
+	memcpy(state->ssh1_key, key, keylen);
+	state->ssh1_keylen = keylen;
+	if ((r = cipher_init(&state->send_context, cipher, key, keylen,
+	    NULL, 0, CIPHER_ENCRYPT)) != 0 ||
+	    (r = cipher_init(&state->receive_context, cipher, key, keylen,
+	    NULL, 0, CIPHER_DECRYPT) != 0))
+		fatal("%s: cipher_init failed: %s", __func__, ssh_err(r));
+	if (!state->cipher_warning_done &&
+	    ((wmsg = cipher_warning_message(&state->send_context)) != NULL ||
+	    (wmsg = cipher_warning_message(&state->send_context)) != NULL)) {
+		error("Warning: %s", wmsg);
+		state->cipher_warning_done = 1;
+	}
 }
 #endif
 
@@ -667,114 +810,126 @@
  * encrypts the packet before sending.
  */
 
-static void
-packet_send1(void)
+int
+ssh_packet_send1(struct ssh *ssh)
 {
+	struct session_state *state = ssh->state;
 	u_char buf[8], *cp;
-	int i, padding, len;
+	int r, padding, len;
 	u_int checksum;
-	u_int32_t rnd = 0;
 
 	/*
 	 * If using packet compression, compress the payload of the outgoing
 	 * packet.
 	 */
-	if (active_state->packet_compression) {
-		buffer_clear(&active_state->compression_buffer);
+	if (state->packet_compression) {
+		sshbuf_reset(state->compression_buffer);
 		/* Skip padding. */
-		buffer_consume(&active_state->outgoing_packet, 8);
+		if ((r = sshbuf_consume(state->outgoing_packet, 8)) != 0)
+			goto out;
 		/* padding */
-		buffer_append(&active_state->compression_buffer,
-		    "\0\0\0\0\0\0\0\0", 8);
-		buffer_compress(&active_state->outgoing_packet,
-		    &active_state->compression_buffer);
-		buffer_clear(&active_state->outgoing_packet);
-		buffer_append(&active_state->outgoing_packet,
-		    buffer_ptr(&active_state->compression_buffer),
-		    buffer_len(&active_state->compression_buffer));
+		if ((r = sshbuf_put(state->compression_buffer,
+		    "\0\0\0\0\0\0\0\0", 8)) != 0)
+			goto out;
+		if ((r = compress_buffer(ssh, state->outgoing_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->outgoing_packet);
+                if ((r = sshbuf_putb(state->outgoing_packet,
+                    state->compression_buffer)) != 0)
+			goto out;
 	}
 	/* Compute packet length without padding (add checksum, remove padding). */
-	len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
+	len = sshbuf_len(state->outgoing_packet) + 4 - 8;
 
 	/* Insert padding. Initialized to zero in packet_start1() */
 	padding = 8 - len % 8;
-	if (!active_state->send_context.plaintext) {
-		cp = buffer_ptr(&active_state->outgoing_packet);
-		for (i = 0; i < padding; i++) {
-			if (i % 4 == 0)
-				rnd = arc4random();
-			cp[7 - i] = rnd & 0xff;
-			rnd >>= 8;
+	if (!state->send_context.plaintext) {
+		cp = sshbuf_mutable_ptr(state->outgoing_packet);
+		if (cp == NULL) {
+			r = SSH_ERR_INTERNAL_ERROR;
+			goto out;
 		}
+		arc4random_buf(cp + 8 - padding, padding);
 	}
-	buffer_consume(&active_state->outgoing_packet, 8 - padding);
+	if ((r = sshbuf_consume(state->outgoing_packet, 8 - padding)) != 0)
+		goto out;
 
 	/* Add check bytes. */
-	checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet),
-	    buffer_len(&active_state->outgoing_packet));
-	put_u32(buf, checksum);
-	buffer_append(&active_state->outgoing_packet, buf, 4);
+	checksum = ssh_crc32(sshbuf_ptr(state->outgoing_packet),
+	    sshbuf_len(state->outgoing_packet));
+	POKE_U32(buf, checksum);
+	if ((r = sshbuf_put(state->outgoing_packet, buf, 4)) != 0)
+		goto out;
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "packet_send plain: ");
-	buffer_dump(&active_state->outgoing_packet);
+	sshbuf_dump(state->outgoing_packet, stderr);
 #endif
 
 	/* Append to output. */
-	put_u32(buf, len);
-	buffer_append(&active_state->output, buf, 4);
-	cp = buffer_append_space(&active_state->output,
-	    buffer_len(&active_state->outgoing_packet));
-	if (cipher_crypt(&active_state->send_context, 0, cp,
-	    buffer_ptr(&active_state->outgoing_packet),
-	    buffer_len(&active_state->outgoing_packet), 0, 0) != 0)
-		fatal("%s: cipher_crypt failed", __func__);
+	POKE_U32(buf, len);
+	if ((r = sshbuf_put(state->output, buf, 4)) != 0)
+		goto out;
+	if ((r = sshbuf_reserve(state->output,
+	    sshbuf_len(state->outgoing_packet), &cp)) != 0)
+		goto out;
+	if ((r = cipher_crypt(&state->send_context, 0, cp,
+	    sshbuf_ptr(state->outgoing_packet),
+	    sshbuf_len(state->outgoing_packet), 0, 0)) != 0)
+		goto out;
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "encrypted: ");
-	buffer_dump(&active_state->output);
+	sshbuf_dump(state->output, stderr);
 #endif
-	active_state->p_send.packets++;
-	active_state->p_send.bytes += len +
-	    buffer_len(&active_state->outgoing_packet);
-	buffer_clear(&active_state->outgoing_packet);
+	state->p_send.packets++;
+	state->p_send.bytes += len +
+	    sshbuf_len(state->outgoing_packet);
+	sshbuf_reset(state->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.
 	 */
+	r = 0;
+ out:
+	return r;
 }
 
-void
-set_newkeys(int mode)
+int
+ssh_set_newkeys(struct ssh *ssh, int mode)
 {
-	Enc *enc;
-	Mac *mac;
-	Comp *comp;
-	CipherContext *cc;
+	struct session_state *state = ssh->state;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct sshcomp *comp;
+	struct sshcipher_ctx *cc;
 	u_int64_t *max_blocks;
+	const char *wmsg;
 	int r, crypt_type;
 
 	debug2("set_newkeys: mode %d", mode);
 
 	if (mode == MODE_OUT) {
-		cc = &active_state->send_context;
+		cc = &state->send_context;
 		crypt_type = CIPHER_ENCRYPT;
-		active_state->p_send.packets = active_state->p_send.blocks = 0;
-		max_blocks = &active_state->max_blocks_out;
+		state->p_send.packets = state->p_send.blocks = 0;
+		max_blocks = &state->max_blocks_out;
 	} else {
-		cc = &active_state->receive_context;
+		cc = &state->receive_context;
 		crypt_type = CIPHER_DECRYPT;
-		active_state->p_read.packets = active_state->p_read.blocks = 0;
-		max_blocks = &active_state->max_blocks_in;
+		state->p_read.packets = state->p_read.blocks = 0;
+		max_blocks = &state->max_blocks_in;
 	}
-	if (active_state->newkeys[mode] != NULL) {
+	if (state->newkeys[mode] != NULL) {
 		debug("set_newkeys: rekeying");
-		cipher_cleanup(cc);
-		enc  = &active_state->newkeys[mode]->enc;
-		mac  = &active_state->newkeys[mode]->mac;
-		comp = &active_state->newkeys[mode]->comp;
+		if ((r = cipher_cleanup(cc)) != 0)
+			return r;
+		enc  = &state->newkeys[mode]->enc;
+		mac  = &state->newkeys[mode]->mac;
+		comp = &state->newkeys[mode]->comp;
 		mac_clear(mac);
 		explicit_bzero(enc->iv,  enc->iv_len);
 		explicit_bzero(enc->key, enc->key_len);
@@ -785,32 +940,45 @@
 		free(mac->name);
 		free(mac->key);
 		free(comp->name);
-		free(active_state->newkeys[mode]);
+		free(state->newkeys[mode]);
 	}
-	active_state->newkeys[mode] = kex_get_newkeys(mode);
-	if (active_state->newkeys[mode] == NULL)
-		fatal("newkeys: no keys for mode %d", mode);
-	enc  = &active_state->newkeys[mode]->enc;
-	mac  = &active_state->newkeys[mode]->mac;
-	comp = &active_state->newkeys[mode]->comp;
-	if (cipher_authlen(enc->cipher) == 0 && mac_init(mac) == 0)
-		mac->enabled = 1;
+	/* move newkeys from kex to state */
+	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->kex->newkeys[mode] = NULL;
+	enc  = &state->newkeys[mode]->enc;
+	mac  = &state->newkeys[mode]->mac;
+	comp = &state->newkeys[mode]->comp;
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = mac_init(mac)) != 0)
+			return r;
+	}
+	mac->enabled = 1;
 	DBG(debug("cipher_init_context: %d", mode));
 	if ((r = cipher_init(cc, enc->cipher, enc->key, enc->key_len,
 	    enc->iv, enc->iv_len, crypt_type)) != 0)
-		fatal("%s: cipher_init: %s", __func__, ssh_err(r));
+		return r;
+	if (!state->cipher_warning_done &&
+	    (wmsg = cipher_warning_message(cc)) != NULL) {
+		error("Warning: %s", wmsg);
+		state->cipher_warning_done = 1;
+	}
 	/* Deleting the keys does not gain extra security */
 	/* explicit_bzero(enc->iv,  enc->block_size);
 	   explicit_bzero(enc->key, enc->key_len);
 	   explicit_bzero(mac->key, mac->key_len); */
 	if ((comp->type == COMP_ZLIB ||
 	    (comp->type == COMP_DELAYED &&
-	     active_state->after_authentication)) && comp->enabled == 0) {
-		packet_init_compression();
-		if (mode == MODE_OUT)
-			buffer_compress_init_send(6);
-		else
-			buffer_compress_init_recv();
+	     state->after_authentication)) && comp->enabled == 0) {
+		if ((r = ssh_packet_init_compression(ssh)) < 0)
+			return r;
+		if (mode == MODE_OUT) {
+			if ((r = start_compression_out(ssh, 6)) != 0)
+				return r;
+		} else {
+			if ((r = start_compression_in(ssh)) != 0)
+				return r;
+		}
 		comp->enabled = 1;
 	}
 	/*
@@ -821,9 +989,10 @@
 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
 	else
 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
-	if (active_state->rekey_limit)
+	if (state->rekey_limit)
 		*max_blocks = MIN(*max_blocks,
-		    active_state->rekey_limit / enc->block_size);
+		    state->rekey_limit / enc->block_size);
+	return 0;
 }
 
 /*
@@ -831,53 +1000,59 @@
  * 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)
+static int
+ssh_packet_enable_delayed_compress(struct ssh *ssh)
 {
-	Comp *comp = NULL;
-	int mode;
+	struct session_state *state = ssh->state;
+	struct sshcomp *comp = NULL;
+	int r, mode;
 
 	/*
 	 * Remember that we are past the authentication step, so rekeying
 	 * with COMP_DELAYED will turn on compression immediately.
 	 */
-	active_state->after_authentication = 1;
+	state->after_authentication = 1;
 	for (mode = 0; mode < MODE_MAX; mode++) {
 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
-		if (active_state->newkeys[mode] == NULL)
+		if (state->newkeys[mode] == NULL)
 			continue;
-		comp = &active_state->newkeys[mode]->comp;
+		comp = &state->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();
+			if ((r = ssh_packet_init_compression(ssh)) != 0)
+				return r;
+			if (mode == MODE_OUT) {
+				if ((r = start_compression_out(ssh, 6)) != 0)
+					return r;
+			} else {
+				if ((r = start_compression_in(ssh)) != 0)
+					return r;
+			}
 			comp->enabled = 1;
 		}
 	}
+	return 0;
 }
 
 /*
  * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
  */
-static void
-packet_send2_wrapped(void)
+int
+ssh_packet_send2_wrapped(struct ssh *ssh)
 {
+	struct session_state *state = ssh->state;
 	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
 	u_char padlen, pad = 0;
-	u_int i, len, authlen = 0, aadlen = 0;
-	u_int32_t rnd = 0;
-	Enc *enc   = NULL;
-	Mac *mac   = NULL;
-	Comp *comp = NULL;
-	int block_size;
-	int r;
+	u_int authlen = 0, aadlen = 0;
+	u_int len;
+	struct sshenc *enc   = NULL;
+	struct sshmac *mac   = NULL;
+	struct sshcomp *comp = NULL;
+	int r, block_size;
 
-	if (active_state->newkeys[MODE_OUT] != NULL) {
-		enc  = &active_state->newkeys[MODE_OUT]->enc;
-		mac  = &active_state->newkeys[MODE_OUT]->mac;
-		comp = &active_state->newkeys[MODE_OUT]->comp;
+	if (state->newkeys[MODE_OUT] != NULL) {
+		enc  = &state->newkeys[MODE_OUT]->enc;
+		mac  = &state->newkeys[MODE_OUT]->mac;
+		comp = &state->newkeys[MODE_OUT]->comp;
 		/* disable mac for authenticated encryption */
 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
 			mac = NULL;
@@ -885,32 +1060,34 @@
 	block_size = enc ? enc->block_size : 8;
 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
 
-	cp = buffer_ptr(&active_state->outgoing_packet);
-	type = cp[5];
+	type = (sshbuf_ptr(state->outgoing_packet))[5];
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "plain:     ");
-	buffer_dump(&active_state->outgoing_packet);
+	sshbuf_dump(state->outgoing_packet, stderr);
 #endif
 
 	if (comp && comp->enabled) {
-		len = buffer_len(&active_state->outgoing_packet);
+		len = sshbuf_len(state->outgoing_packet);
 		/* skip header, compress only payload */
-		buffer_consume(&active_state->outgoing_packet, 5);
-		buffer_clear(&active_state->compression_buffer);
-		buffer_compress(&active_state->outgoing_packet,
-		    &active_state->compression_buffer);
-		buffer_clear(&active_state->outgoing_packet);
-		buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
-		buffer_append(&active_state->outgoing_packet,
-		    buffer_ptr(&active_state->compression_buffer),
-		    buffer_len(&active_state->compression_buffer));
-		DBG(debug("compression: raw %d compressed %d", len,
-		    buffer_len(&active_state->outgoing_packet)));
+		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
+			goto out;
+		sshbuf_reset(state->compression_buffer);
+		if ((r = compress_buffer(ssh, state->outgoing_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->outgoing_packet);
+		if ((r = sshbuf_put(state->outgoing_packet,
+		    "\0\0\0\0\0", 5)) != 0 ||
+		    (r = sshbuf_putb(state->outgoing_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		DBG(debug("compression: raw %d compressed %zd", len,
+		    sshbuf_len(state->outgoing_packet)));
 	}
 
 	/* sizeof (packet_len + pad_len + payload) */
-	len = buffer_len(&active_state->outgoing_packet);
+	len = sshbuf_len(state->outgoing_packet);
 
 	/*
 	 * calc size of padding, alloc space, get random data,
@@ -920,143 +1097,145 @@
 	padlen = block_size - (len % block_size);
 	if (padlen < 4)
 		padlen += block_size;
-	if (active_state->extra_pad) {
+	if (state->extra_pad) {
 		/* will wrap if extra_pad+padlen > 255 */
-		active_state->extra_pad =
-		    roundup(active_state->extra_pad, block_size);
-		pad = active_state->extra_pad -
-		    ((len + padlen) % active_state->extra_pad);
+		state->extra_pad =
+		    roundup(state->extra_pad, block_size);
+		pad = state->extra_pad -
+		    ((len + padlen) % state->extra_pad);
 		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
-		    __func__, pad, len, padlen, active_state->extra_pad));
+		    __func__, pad, len, padlen, state->extra_pad));
 		padlen += pad;
-		active_state->extra_pad = 0;
+		state->extra_pad = 0;
 	}
-	cp = buffer_append_space(&active_state->outgoing_packet, padlen);
-	if (enc && !active_state->send_context.plaintext) {
+	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
+		goto out;
+	if (enc && !state->send_context.plaintext) {
 		/* random padding */
-		for (i = 0; i < padlen; i++) {
-			if (i % 4 == 0)
-				rnd = arc4random();
-			cp[i] = rnd & 0xff;
-			rnd >>= 8;
-		}
+		arc4random_buf(cp, padlen);
 	} else {
 		/* clear padding */
 		explicit_bzero(cp, padlen);
 	}
 	/* sizeof (packet_len + pad_len + payload + padding) */
-	len = buffer_len(&active_state->outgoing_packet);
-	cp = buffer_ptr(&active_state->outgoing_packet);
+	len = sshbuf_len(state->outgoing_packet);
+	cp = sshbuf_mutable_ptr(state->outgoing_packet);
+	if (cp == NULL) {
+		r = SSH_ERR_INTERNAL_ERROR;
+		goto out;
+	}
 	/* packet_length includes payload, padding and padding length field */
-	put_u32(cp, len - 4);
+	POKE_U32(cp, len - 4);
 	cp[4] = padlen;
 	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
 	    len, padlen, aadlen));
 
 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
 	if (mac && mac->enabled && !mac->etm) {
-		if ((r = mac_compute(mac, active_state->p_send.seqnr,
-		    buffer_ptr(&active_state->outgoing_packet), len,
+		if ((r = mac_compute(mac, state->p_send.seqnr,
+		    sshbuf_ptr(state->outgoing_packet), len,
 		    macbuf, sizeof(macbuf))) != 0)
-			fatal("%s: mac_compute: %s", __func__, ssh_err(r));
-		DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
+			goto out;
+		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
 	}
 	/* encrypt packet and append to output buffer. */
-	cp = buffer_append_space(&active_state->output, len + authlen);
-	if (cipher_crypt(&active_state->send_context, active_state->p_send.seqnr,
-	    cp, buffer_ptr(&active_state->outgoing_packet),
-	    len - aadlen, aadlen, authlen) != 0)
-		fatal("%s: cipher_crypt failed", __func__);
+	if ((r = sshbuf_reserve(state->output,
+	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
+		goto out;
+	if ((r = cipher_crypt(&state->send_context, state->p_send.seqnr, cp,
+	    sshbuf_ptr(state->outgoing_packet),
+	    len - aadlen, aadlen, authlen)) != 0)
+		goto out;
 	/* append unencrypted MAC */
 	if (mac && mac->enabled) {
 		if (mac->etm) {
 			/* EtM: compute mac over aadlen + cipher text */
-			if ((r = mac_compute(mac,
-			    active_state->p_send.seqnr, cp, len,
-			    macbuf, sizeof(macbuf))) != 0)
-				fatal("%s: mac_compute: %s", __func__, ssh_err(r));
+			if ((r = mac_compute(mac, state->p_send.seqnr,
+			    cp, len, macbuf, sizeof(macbuf))) != 0)
+				goto out;
 			DBG(debug("done calc MAC(EtM) out #%d",
-			    active_state->p_send.seqnr));
+			    state->p_send.seqnr));
 		}
-		buffer_append(&active_state->output, macbuf, mac->mac_len);
+		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
+			goto out;
 	}
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "encrypted: ");
-	buffer_dump(&active_state->output);
+	sshbuf_dump(state->output, stderr);
 #endif
 	/* increment sequence number for outgoing packets */
-	if (++active_state->p_send.seqnr == 0)
+	if (++state->p_send.seqnr == 0)
 		logit("outgoing seqnr wraps around");
-	if (++active_state->p_send.packets == 0)
-		if (!(datafellows & SSH_BUG_NOREKEY))
-			fatal("XXX too many packets with same key");
-	active_state->p_send.blocks += len / block_size;
-	active_state->p_send.bytes += len;
-	buffer_clear(&active_state->outgoing_packet);
+	if (++state->p_send.packets == 0)
+		if (!(ssh->compat & SSH_BUG_NOREKEY))
+			return SSH_ERR_NEED_REKEY;
+	state->p_send.blocks += len / block_size;
+	state->p_send.bytes += len;
+	sshbuf_reset(state->outgoing_packet);
 
 	if (type == SSH2_MSG_NEWKEYS)
-		set_newkeys(MODE_OUT);
-	else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
-		packet_enable_delayed_compress();
+		r = ssh_set_newkeys(ssh, MODE_OUT);
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
+		r = ssh_packet_enable_delayed_compress(ssh);
+	else
+		r = 0;
+ out:
+	return r;
 }
 
-static void
-packet_send2(void)
+int
+ssh_packet_send2(struct ssh *ssh)
 {
+	struct session_state *state = ssh->state;
 	struct packet *p;
-	u_char type, *cp;
+	u_char type;
+	int r;
 
-	cp = buffer_ptr(&active_state->outgoing_packet);
-	type = cp[5];
+	type = sshbuf_ptr(state->outgoing_packet)[5];
 
 	/* during rekeying we can only send key exchange messages */
-	if (active_state->rekeying) {
+	if (state->rekeying) {
 		if ((type < SSH2_MSG_TRANSPORT_MIN) ||
 		    (type > SSH2_MSG_TRANSPORT_MAX) ||
 		    (type == SSH2_MSG_SERVICE_REQUEST) ||
 		    (type == SSH2_MSG_SERVICE_ACCEPT)) {
 			debug("enqueue packet: %u", type);
-			p = xcalloc(1, sizeof(*p));
+			p = calloc(1, sizeof(*p));
+			if (p == NULL)
+				return SSH_ERR_ALLOC_FAIL;
 			p->type = type;
-			memcpy(&p->payload, &active_state->outgoing_packet,
-			    sizeof(Buffer));
-			buffer_init(&active_state->outgoing_packet);
-			TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
-			return;
+			p->payload = state->outgoing_packet;
+			TAILQ_INSERT_TAIL(&state->outgoing, p, next);
+			state->outgoing_packet = sshbuf_new();
+			if (state->outgoing_packet == NULL)
+				return SSH_ERR_ALLOC_FAIL;
+			return 0;
 		}
 	}
 
 	/* rekeying starts with sending KEXINIT */
 	if (type == SSH2_MSG_KEXINIT)
-		active_state->rekeying = 1;
+		state->rekeying = 1;
 
-	packet_send2_wrapped();
+	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
+		return r;
 
 	/* after a NEWKEYS message we can send the complete queue */
 	if (type == SSH2_MSG_NEWKEYS) {
-		active_state->rekeying = 0;
-		active_state->rekey_time = monotime();
-		while ((p = TAILQ_FIRST(&active_state->outgoing))) {
+		state->rekeying = 0;
+		state->rekey_time = monotime();
+		while ((p = TAILQ_FIRST(&state->outgoing))) {
 			type = p->type;
 			debug("dequeue packet: %u", type);
-			buffer_free(&active_state->outgoing_packet);
-			memcpy(&active_state->outgoing_packet, &p->payload,
-			    sizeof(Buffer));
-			TAILQ_REMOVE(&active_state->outgoing, p, next);
+			sshbuf_free(state->outgoing_packet);
+			state->outgoing_packet = p->payload;
+			TAILQ_REMOVE(&state->outgoing, p, next);
 			free(p);
-			packet_send2_wrapped();
+			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
+				return r;
 		}
 	}
-}
-
-void
-packet_send(void)
-{
-	if (compat20)
-		packet_send2();
-	else
-		packet_send1();
-	DBG(debug("packet_send done"));
+	return 0;
 }
 
 /*
@@ -1066,95 +1245,106 @@
  */
 
 int
-packet_read_seqnr(u_int32_t *seqnr_p)
+ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
 {
-	int type, len, ret, cont, ms_remain = 0;
+	struct session_state *state = ssh->state;
+	int len, r, ms_remain, cont;
 	fd_set *setp;
 	char buf[8192];
 	struct timeval timeout, start, *timeoutp = NULL;
 
 	DBG(debug("packet_read()"));
 
-	setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
+	setp = (fd_set *)calloc(howmany(state->connection_in + 1,
 	    NFDBITS), sizeof(fd_mask));
+	if (setp == NULL)
+		return SSH_ERR_ALLOC_FAIL;
 
 	/* Since we are blocking, ensure that all written packets have been sent. */
-	packet_write_wait();
+	ssh_packet_write_wait(ssh);
 
 	/* 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);
+		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
+		if (r != 0)
+			break;
 		if (!compat20 && (
-		    type == SSH_SMSG_SUCCESS
-		    || type == SSH_SMSG_FAILURE
-		    || type == SSH_CMSG_EOF
-		    || type == SSH_CMSG_EXIT_CONFIRMATION))
-			packet_check_eom();
+		    *typep == SSH_SMSG_SUCCESS
+		    || *typep == SSH_SMSG_FAILURE
+		    || *typep == SSH_CMSG_EOF
+		    || *typep == SSH_CMSG_EXIT_CONFIRMATION))
+			if ((r = sshpkt_get_end(ssh)) != 0)
+				break;
 		/* If we got a packet, return it. */
-		if (type != SSH_MSG_NONE) {
-			free(setp);
-			return type;
-		}
+		if (*typep != SSH_MSG_NONE)
+			break;
 		/*
 		 * Otherwise, wait for some data to arrive, add it to the
 		 * buffer, and try again.
 		 */
-		memset(setp, 0, howmany(active_state->connection_in + 1,
+		memset(setp, 0, howmany(state->connection_in + 1,
 		    NFDBITS) * sizeof(fd_mask));
-		FD_SET(active_state->connection_in, setp);
+		FD_SET(state->connection_in, setp);
 
-		if (active_state->packet_timeout_ms > 0) {
-			ms_remain = active_state->packet_timeout_ms;
+		if (state->packet_timeout_ms > 0) {
+			ms_remain = state->packet_timeout_ms;
 			timeoutp = &timeout;
 		}
 		/* Wait for some data to arrive. */
 		for (;;) {
-			if (active_state->packet_timeout_ms != -1) {
+			if (state->packet_timeout_ms != -1) {
 				ms_to_timeval(&timeout, ms_remain);
 				gettimeofday(&start, NULL);
 			}
-			if ((ret = select(active_state->connection_in + 1, setp,
+			if ((r = select(state->connection_in + 1, setp,
 			    NULL, NULL, timeoutp)) >= 0)
 				break;
 			if (errno != EAGAIN && errno != EINTR &&
 			    errno != EWOULDBLOCK)
 				break;
-			if (active_state->packet_timeout_ms == -1)
+			if (state->packet_timeout_ms == -1)
 				continue;
 			ms_subtract_diff(&start, &ms_remain);
 			if (ms_remain <= 0) {
-				ret = 0;
+				r = 0;
 				break;
 			}
 		}
-		if (ret == 0) {
+		if (r == 0) {
 			logit("Connection to %.200s timed out while "
-			    "waiting to read", get_remote_ipaddr());
+			    "waiting to read", ssh_remote_ipaddr(ssh));
 			cleanup_exit(255);
 		}
 		/* Read data from the socket. */
 		do {
 			cont = 0;
-			len = roaming_read(active_state->connection_in, buf,
+			len = roaming_read(state->connection_in, buf,
 			    sizeof(buf), &cont);
 		} while (len == 0 && cont);
 		if (len == 0) {
-			logit("Connection closed by %.200s", get_remote_ipaddr());
+			logit("Connection closed by %.200s",
+			    ssh_remote_ipaddr(ssh));
 			cleanup_exit(255);
 		}
 		if (len < 0)
 			fatal("Read from socket failed: %.100s", strerror(errno));
 		/* Append it to the buffer. */
-		packet_process_incoming(buf, len);
+		ssh_packet_process_incoming(ssh, buf, len);
 	}
-	/* NOTREACHED */
+	free(setp);
+	return r;
 }
 
 int
-packet_read(void)
+ssh_packet_read(struct ssh *ssh)
 {
-	return packet_read_seqnr(NULL);
+	u_char type;
+	int r;
+
+	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
+	return type;
 }
 
 /*
@@ -1163,13 +1353,14 @@
  */
 
 void
-packet_read_expect(int expected_type)
+ssh_packet_read_expect(struct ssh *ssh, int expected_type)
 {
 	int type;
 
-	type = packet_read();
+	type = ssh_packet_read(ssh);
 	if (type != expected_type)
-		packet_disconnect("Protocol error: expected packet type %d, got %d",
+		ssh_packet_disconnect(ssh,
+		    "Protocol error: expected packet type %d, got %d",
 		    expected_type, type);
 }
 
@@ -1182,116 +1373,141 @@
  * to higher levels.
  */
 
-static int
-packet_read_poll1(void)
+int
+ssh_packet_read_poll1(struct ssh *ssh, u_char *typep)
 {
+	struct session_state *state = ssh->state;
 	u_int len, padded_len;
-	u_char *cp, type;
+	const u_char *cp;
+	u_char *p;
 	u_int checksum, stored_checksum;
+	int r;
+
+	*typep = SSH_MSG_NONE;
 
 	/* Check if input size is less than minimum packet size. */
-	if (buffer_len(&active_state->input) < 4 + 8)
-		return SSH_MSG_NONE;
+	if (sshbuf_len(state->input) < 4 + 8)
+		return 0;
 	/* Get length of incoming packet. */
-	cp = buffer_ptr(&active_state->input);
-	len = get_u32(cp);
+	len = PEEK_U32(sshbuf_ptr(state->input));
 	if (len < 1 + 2 + 2 || len > 256 * 1024)
-		packet_disconnect("Bad packet length %u.", len);
+		ssh_packet_disconnect(ssh, "Bad packet length %u.",
+		    len);
 	padded_len = (len + 8) & ~7;
 
 	/* Check if the packet has been entirely received. */
-	if (buffer_len(&active_state->input) < 4 + padded_len)
-		return SSH_MSG_NONE;
+	if (sshbuf_len(state->input) < 4 + padded_len)
+		return 0;
 
 	/* The entire packet is in buffer. */
 
 	/* Consume packet length. */
-	buffer_consume(&active_state->input, 4);
+	if ((r = sshbuf_consume(state->input, 4)) != 0)
+		goto out;
 
 	/*
 	 * Cryptographic attack detector for ssh
 	 * (C)1998 CORE-SDI, Buenos Aires Argentina
 	 * Ariel Futoransky(futo@core-sdi.com)
 	 */
-	if (!active_state->receive_context.plaintext) {
-		switch (detect_attack(buffer_ptr(&active_state->input),
-		    padded_len)) {
+	if (!state->receive_context.plaintext) {
+		switch (detect_attack(&state->deattack,
+		    sshbuf_ptr(state->input), padded_len)) {
+		case DEATTACK_OK:
+			break;
 		case DEATTACK_DETECTED:
-			packet_disconnect("crc32 compensation attack: "
-			    "network attack detected");
+			ssh_packet_disconnect(ssh,
+			    "crc32 compensation attack: network attack detected"
+			);
 		case DEATTACK_DOS_DETECTED:
-			packet_disconnect("deattack denial of "
-			    "service detected");
+			ssh_packet_disconnect(ssh,
+			    "deattack denial of service detected");
+		default:
+			ssh_packet_disconnect(ssh, "deattack error");
 		}
 	}
 
 	/* Decrypt data to incoming_packet. */
-	buffer_clear(&active_state->incoming_packet);
-	cp = buffer_append_space(&active_state->incoming_packet, padded_len);
-	if (cipher_crypt(&active_state->receive_context, 0, cp,
-	    buffer_ptr(&active_state->input), padded_len, 0, 0) != 0)
-		fatal("%s: cipher_crypt failed", __func__);
+	sshbuf_reset(state->incoming_packet);
+	if ((r = sshbuf_reserve(state->incoming_packet, padded_len, &p)) != 0)
+		goto out;
+	if ((r = cipher_crypt(&state->receive_context, 0, p,
+	    sshbuf_ptr(state->input), padded_len, 0, 0)) != 0)
+		goto out;
 
-	buffer_consume(&active_state->input, padded_len);
+	if ((r = sshbuf_consume(state->input, padded_len)) != 0)
+		goto out;
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "read_poll plain: ");
-	buffer_dump(&active_state->incoming_packet);
+	sshbuf_dump(state->incoming_packet, stderr);
 #endif
 
 	/* Compute packet checksum. */
-	checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
-	    buffer_len(&active_state->incoming_packet) - 4);
+	checksum = ssh_crc32(sshbuf_ptr(state->incoming_packet),
+	    sshbuf_len(state->incoming_packet) - 4);
 
 	/* Skip padding. */
-	buffer_consume(&active_state->incoming_packet, 8 - len % 8);
+	if ((r = sshbuf_consume(state->incoming_packet, 8 - len % 8)) != 0)
+		goto out;
 
 	/* Test check bytes. */
-	if (len != buffer_len(&active_state->incoming_packet))
-		packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
-		    len, buffer_len(&active_state->incoming_packet));
+	if (len != sshbuf_len(state->incoming_packet))
+		ssh_packet_disconnect(ssh,
+		    "packet_read_poll1: len %d != sshbuf_len %zd.",
+		    len, sshbuf_len(state->incoming_packet));
 
-	cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
-	stored_checksum = get_u32(cp);
+	cp = sshbuf_ptr(state->incoming_packet) + len - 4;
+	stored_checksum = PEEK_U32(cp);
 	if (checksum != stored_checksum)
-		packet_disconnect("Corrupted check bytes on input.");
-	buffer_consume_end(&active_state->incoming_packet, 4);
+		ssh_packet_disconnect(ssh,
+		    "Corrupted check bytes on input.");
+	if ((r = sshbuf_consume_end(state->incoming_packet, 4)) < 0)
+		goto out;
 
-	if (active_state->packet_compression) {
-		buffer_clear(&active_state->compression_buffer);
-		buffer_uncompress(&active_state->incoming_packet,
-		    &active_state->compression_buffer);
-		buffer_clear(&active_state->incoming_packet);
-		buffer_append(&active_state->incoming_packet,
-		    buffer_ptr(&active_state->compression_buffer),
-		    buffer_len(&active_state->compression_buffer));
+	if (state->packet_compression) {
+		sshbuf_reset(state->compression_buffer);
+		if ((r = uncompress_buffer(ssh, state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->incoming_packet);
+		if ((r = sshbuf_putb(state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
 	}
-	active_state->p_read.packets++;
-	active_state->p_read.bytes += padded_len + 4;
-	type = buffer_get_char(&active_state->incoming_packet);
-	if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
-		packet_disconnect("Invalid ssh1 packet type: %d", type);
-	return type;
+	state->p_read.packets++;
+	state->p_read.bytes += padded_len + 4;
+	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
+		goto out;
+	if (*typep < SSH_MSG_MIN || *typep > SSH_MSG_MAX)
+		ssh_packet_disconnect(ssh,
+		    "Invalid ssh1 packet type: %d", *typep);
+	r = 0;
+ out:
+	return r;
 }
 
-static int
-packet_read_poll2(u_int32_t *seqnr_p)
+int
+ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
 {
+	struct session_state *state = ssh->state;
 	u_int padlen, need;
-	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
-	u_int maclen, authlen = 0, aadlen = 0, block_size;
+	u_char *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
+	u_int maclen, aadlen = 0, authlen = 0, block_size;
+	struct sshenc *enc   = NULL;
+	struct sshmac *mac   = NULL;
+	struct sshcomp *comp = NULL;
 	int r;
-	Enc *enc   = NULL;
-	Mac *mac   = NULL;
-	Comp *comp = NULL;
 
-	if (active_state->packet_discard)
-		return SSH_MSG_NONE;
+	*typep = SSH_MSG_NONE;
 
-	if (active_state->newkeys[MODE_IN] != NULL) {
-		enc  = &active_state->newkeys[MODE_IN]->enc;
-		mac  = &active_state->newkeys[MODE_IN]->mac;
-		comp = &active_state->newkeys[MODE_IN]->comp;
+	if (state->packet_discard)
+		return 0;
+
+	if (state->newkeys[MODE_IN] != NULL) {
+		enc  = &state->newkeys[MODE_IN]->enc;
+		mac  = &state->newkeys[MODE_IN]->mac;
+		comp = &state->newkeys[MODE_IN]->comp;
 		/* disable mac for authenticated encryption */
 		if ((authlen = cipher_authlen(enc->cipher)) != 0)
 			mac = NULL;
@@ -1300,69 +1516,71 @@
 	block_size = enc ? enc->block_size : 8;
 	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
 
-	if (aadlen && active_state->packlen == 0) {
-		if (cipher_get_length(&active_state->receive_context,
-		    &active_state->packlen,
-		    active_state->p_read.seqnr,
-		    buffer_ptr(&active_state->input),
-		    buffer_len(&active_state->input)) != 0)
-			return SSH_MSG_NONE;
-		if (active_state->packlen < 1 + 4 ||
-		    active_state->packlen > PACKET_MAX_SIZE) {
+	if (aadlen && state->packlen == 0) {
+		if (cipher_get_length(&state->receive_context,
+		    &state->packlen, state->p_read.seqnr,
+		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
+			return 0;
+		if (state->packlen < 1 + 4 ||
+		    state->packlen > PACKET_MAX_SIZE) {
 #ifdef PACKET_DEBUG
-			buffer_dump(&active_state->input);
+			sshbuf_dump(state->input, stderr);
 #endif
-			logit("Bad packet length %u.", active_state->packlen);
-			packet_disconnect("Packet corrupt");
+			logit("Bad packet length %u.", state->packlen);
+			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
+				return r;
 		}
-		buffer_clear(&active_state->incoming_packet);
-	} else if (active_state->packlen == 0) {
+		sshbuf_reset(state->incoming_packet);
+	} else if (state->packlen == 0) {
 		/*
 		 * check if input size is less than the cipher block size,
 		 * decrypt first block and extract length of incoming packet
 		 */
-		if (buffer_len(&active_state->input) < block_size)
-			return SSH_MSG_NONE;
-		buffer_clear(&active_state->incoming_packet);
-		cp = buffer_append_space(&active_state->incoming_packet,
-		    block_size);
-		if (cipher_crypt(&active_state->receive_context,
-		    active_state->p_read.seqnr, cp,
-		    buffer_ptr(&active_state->input), block_size, 0, 0) != 0)
-			fatal("Decryption integrity check failed");
-		cp = buffer_ptr(&active_state->incoming_packet);
-		active_state->packlen = get_u32(cp);
-		if (active_state->packlen < 1 + 4 ||
-		    active_state->packlen > PACKET_MAX_SIZE) {
+		if (sshbuf_len(state->input) < block_size)
+			return 0;
+		sshbuf_reset(state->incoming_packet);
+		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
+		    &cp)) != 0)
+			goto out;
+		if ((r = cipher_crypt(&state->receive_context,
+		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
+		    block_size, 0, 0)) != 0)
+			goto out;
+		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
+		if (state->packlen < 1 + 4 ||
+		    state->packlen > PACKET_MAX_SIZE) {
 #ifdef PACKET_DEBUG
-			buffer_dump(&active_state->incoming_packet);
+			fprintf(stderr, "input: \n");
+			sshbuf_dump(state->input, stderr);
+			fprintf(stderr, "incoming_packet: \n");
+			sshbuf_dump(state->incoming_packet, stderr);
 #endif
-			logit("Bad packet length %u.", active_state->packlen);
-			packet_start_discard(enc, mac, active_state->packlen,
-			    PACKET_MAX_SIZE);
-			return SSH_MSG_NONE;
+			logit("Bad packet length %u.", state->packlen);
+			return ssh_packet_start_discard(ssh, enc, mac,
+			    state->packlen, PACKET_MAX_SIZE);
 		}
-		buffer_consume(&active_state->input, block_size);
+		if ((r = sshbuf_consume(state->input, block_size)) != 0)
+			goto out;
 	}
-	DBG(debug("input: packet len %u", active_state->packlen+4));
+	DBG(debug("input: packet len %u", state->packlen+4));
+
 	if (aadlen) {
 		/* only the payload is encrypted */
-		need = active_state->packlen;
+		need = state->packlen;
 	} else {
 		/*
 		 * the payload size and the payload are encrypted, but we
 		 * have a partial packet of block_size bytes
 		 */
-		need = 4 + active_state->packlen - block_size;
+		need = 4 + state->packlen - block_size;
 	}
 	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
 	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
 	if (need % block_size != 0) {
 		logit("padding error: need %d block %d mod %d",
 		    need, block_size, need % block_size);
-		packet_start_discard(enc, mac, active_state->packlen,
-		    PACKET_MAX_SIZE - block_size);
-		return SSH_MSG_NONE;
+		return ssh_packet_start_discard(ssh, enc, mac,
+		    state->packlen, PACKET_MAX_SIZE - block_size);
 	}
 	/*
 	 * check if the entire packet has been received and
@@ -1372,171 +1590,190 @@
 	 * 'authlen' bytes of authentication tag or
 	 * 'maclen' bytes of message authentication code.
 	 */
-	if (buffer_len(&active_state->input) < aadlen + need + authlen + maclen)
-		return SSH_MSG_NONE;
+	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
+		return 0;
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "read_poll enc/full: ");
-	buffer_dump(&active_state->input);
+	sshbuf_dump(state->input, stderr);
 #endif
 	/* EtM: compute mac over encrypted input */
-	if (mac && mac->enabled && mac->etm)
-		if ((r = mac_compute(mac, active_state->p_read.seqnr,
-		    buffer_ptr(&active_state->input), aadlen + need,
+	if (mac && mac->enabled && mac->etm) {
+		if ((r = mac_compute(mac, state->p_read.seqnr,
+		    sshbuf_ptr(state->input), aadlen + need,
 		    macbuf, sizeof(macbuf))) != 0)
-			fatal("%s: mac_compute: %s", __func__, ssh_err(r));
-	cp = buffer_append_space(&active_state->incoming_packet, aadlen + need);
-	if (cipher_crypt(&active_state->receive_context,
-	    active_state->p_read.seqnr, cp,
-	    buffer_ptr(&active_state->input), need, aadlen, authlen) != 0)
-		fatal("Decryption integrity check failed");
-	buffer_consume(&active_state->input, aadlen + need + authlen);
+			goto out;
+	}
+	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
+	    &cp)) != 0)
+		goto out;
+	if ((r = cipher_crypt(&state->receive_context, state->p_read.seqnr, cp,
+	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
+		goto out;
+	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
+		goto out;
 	/*
 	 * compute MAC over seqnr and packet,
 	 * increment sequence number for incoming packet
 	 */
 	if (mac && mac->enabled) {
 		if (!mac->etm)
-			if ((r = mac_compute(mac, active_state->p_read.seqnr,
-			    buffer_ptr(&active_state->incoming_packet),
-			    buffer_len(&active_state->incoming_packet),
+			if ((r = mac_compute(mac, state->p_read.seqnr,
+			    sshbuf_ptr(state->incoming_packet),
+			    sshbuf_len(state->incoming_packet),
 			    macbuf, sizeof(macbuf))) != 0)
-				fatal("%s: mac_compute: %s", __func__, ssh_err(r));
-		if (timingsafe_bcmp(macbuf, buffer_ptr(&active_state->input),
+				goto out;
+		if (timingsafe_bcmp(macbuf, sshbuf_ptr(state->input),
 		    mac->mac_len) != 0) {
 			logit("Corrupted MAC on input.");
 			if (need > PACKET_MAX_SIZE)
-				fatal("internal error need %d", need);
-			packet_start_discard(enc, mac, active_state->packlen,
-			    PACKET_MAX_SIZE - need);
-			return SSH_MSG_NONE;
+				return SSH_ERR_INTERNAL_ERROR;
+			return ssh_packet_start_discard(ssh, enc, mac,
+			    state->packlen, PACKET_MAX_SIZE - need);
 		}
-				
-		DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
-		buffer_consume(&active_state->input, mac->mac_len);
+
+		DBG(debug("MAC #%d ok", state->p_read.seqnr));
+		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
+			goto out;
 	}
 	/* XXX now it's safe to use fatal/packet_disconnect */
 	if (seqnr_p != NULL)
-		*seqnr_p = active_state->p_read.seqnr;
-	if (++active_state->p_read.seqnr == 0)
+		*seqnr_p = state->p_read.seqnr;
+	if (++state->p_read.seqnr == 0)
 		logit("incoming seqnr wraps around");
-	if (++active_state->p_read.packets == 0)
-		if (!(datafellows & SSH_BUG_NOREKEY))
-			fatal("XXX too many packets with same key");
-	active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
-	active_state->p_read.bytes += active_state->packlen + 4;
+	if (++state->p_read.packets == 0)
+		if (!(ssh->compat & SSH_BUG_NOREKEY))
+			return SSH_ERR_NEED_REKEY;
+	state->p_read.blocks += (state->packlen + 4) / block_size;
+	state->p_read.bytes += state->packlen + 4;
 
 	/* get padlen */
-	cp = buffer_ptr(&active_state->incoming_packet);
-	padlen = cp[4];
+	padlen = sshbuf_ptr(state->incoming_packet)[4];
 	DBG(debug("input: padlen %d", padlen));
 	if (padlen < 4)
-		packet_disconnect("Corrupted padlen %d on input.", padlen);
+		ssh_packet_disconnect(ssh,
+		    "Corrupted padlen %d on input.", padlen);
 
 	/* skip packet size + padlen, discard padding */
-	buffer_consume(&active_state->incoming_packet, 4 + 1);
-	buffer_consume_end(&active_state->incoming_packet, padlen);
+	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
+	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
+		goto out;
 
-	DBG(debug("input: len before de-compress %d",
-	    buffer_len(&active_state->incoming_packet)));
+	DBG(debug("input: len before de-compress %zd",
+	    sshbuf_len(state->incoming_packet)));
 	if (comp && comp->enabled) {
-		buffer_clear(&active_state->compression_buffer);
-		buffer_uncompress(&active_state->incoming_packet,
-		    &active_state->compression_buffer);
-		buffer_clear(&active_state->incoming_packet);
-		buffer_append(&active_state->incoming_packet,
-		    buffer_ptr(&active_state->compression_buffer),
-		    buffer_len(&active_state->compression_buffer));
-		DBG(debug("input: len after de-compress %d",
-		    buffer_len(&active_state->incoming_packet)));
+		sshbuf_reset(state->compression_buffer);
+		if ((r = uncompress_buffer(ssh, state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->incoming_packet);
+		if ((r = sshbuf_putb(state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		DBG(debug("input: len after de-compress %zd",
+		    sshbuf_len(state->incoming_packet)));
 	}
 	/*
 	 * get packet type, implies consume.
 	 * return length of payload (without type field)
 	 */
-	type = buffer_get_char(&active_state->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 &&
-	    !active_state->server_side)
-		packet_enable_delayed_compress();
+	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
+		goto out;
+	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN)
+		ssh_packet_disconnect(ssh,
+		    "Invalid ssh2 packet type: %d", *typep);
+	if (*typep == SSH2_MSG_NEWKEYS)
+		r = ssh_set_newkeys(ssh, MODE_IN);
+	else if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
+		r = ssh_packet_enable_delayed_compress(ssh);
+	else
+		r = 0;
 #ifdef PACKET_DEBUG
-	fprintf(stderr, "read/plain[%d]:\r\n", type);
-	buffer_dump(&active_state->incoming_packet);
+	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
+	sshbuf_dump(state->incoming_packet, stderr);
 #endif
 	/* reset for next packet */
-	active_state->packlen = 0;
-	return type;
+	state->packlen = 0;
+ out:
+	return r;
 }
 
 int
-packet_read_poll_seqnr(u_int32_t *seqnr_p)
+ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
 {
+	struct session_state *state = ssh->state;
 	u_int reason, seqnr;
-	u_char type;
-	char *msg;
+	int r;
+	u_char *msg;
 
 	for (;;) {
+		msg = NULL;
 		if (compat20) {
-			type = packet_read_poll2(seqnr_p);
-			if (type) {
-				active_state->keep_alive_timeouts = 0;
-				DBG(debug("received packet type %d", type));
+			r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
+			if (r != 0)
+				return r;
+			if (*typep) {
+				state->keep_alive_timeouts = 0;
+				DBG(debug("received packet type %d", *typep));
 			}
-			switch (type) {
+			switch (*typep) {
 			case SSH2_MSG_IGNORE:
 				debug3("Received SSH2_MSG_IGNORE");
 				break;
 			case SSH2_MSG_DEBUG:
-				packet_get_char();
-				msg = packet_get_string(NULL);
+				if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
+				    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
+				    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
+					if (msg)
+						free(msg);
+					return r;
+				}
 				debug("Remote: %.900s", msg);
 				free(msg);
-				msg = packet_get_string(NULL);
-				free(msg);
 				break;
 			case SSH2_MSG_DISCONNECT:
-				reason = packet_get_int();
-				msg = packet_get_string(NULL);
+				if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
+				    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
+					return r;
 				/* Ignore normal client exit notifications */
-				do_log2(active_state->server_side &&
+				do_log2(ssh->state->server_side &&
 				    reason == SSH2_DISCONNECT_BY_APPLICATION ?
 				    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
 				    "Received disconnect from %s: %u: %.400s",
-				    get_remote_ipaddr(), reason, msg);
+				    ssh_remote_ipaddr(ssh), reason, msg);
 				free(msg);
-				cleanup_exit(255);
-				break;
+				return SSH_ERR_DISCONNECTED;
 			case SSH2_MSG_UNIMPLEMENTED:
-				seqnr = packet_get_int();
+				if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
+					return r;
 				debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
 				    seqnr);
 				break;
 			default:
-				return type;
+				return 0;
 			}
 		} else {
-			type = packet_read_poll1();
-			switch (type) {
+			r = ssh_packet_read_poll1(ssh, typep);
+			switch (*typep) {
 			case SSH_MSG_NONE:
 				return SSH_MSG_NONE;
 			case SSH_MSG_IGNORE:
 				break;
 			case SSH_MSG_DEBUG:
-				msg = packet_get_string(NULL);
+				if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
+					return r;
 				debug("Remote: %.900s", msg);
 				free(msg);
 				break;
 			case SSH_MSG_DISCONNECT:
-				msg = packet_get_string(NULL);
+				if ((r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
+					return r;
 				error("Received disconnect from %s: %.400s",
-				    get_remote_ipaddr(), msg);
-				cleanup_exit(255);
-				break;
+				    ssh_remote_ipaddr(ssh), msg);
+				free(msg);
+				return SSH_ERR_DISCONNECTED;
 			default:
-				DBG(debug("received packet type %d", type));
-				return type;
+				DBG(debug("received packet type %d", *typep));
+				return 0;
 			}
 		}
 	}
@@ -1548,112 +1785,29 @@
  */
 
 void
-packet_process_incoming(const char *buf, u_int len)
+ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
 {
-	if (active_state->packet_discard) {
-		active_state->keep_alive_timeouts = 0; /* ?? */
-		if (len >= active_state->packet_discard)
-			packet_stop_discard();
-		active_state->packet_discard -= len;
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (state->packet_discard) {
+		state->keep_alive_timeouts = 0; /* ?? */
+		if (len >= state->packet_discard) {
+			if ((r = ssh_packet_stop_discard(ssh)) != 0)
+				fatal("%s: %s", __func__, ssh_err(r));
+			cleanup_exit(255);
+		}
+		state->packet_discard -= len;
 		return;
 	}
-	buffer_append(&active_state->input, buf, len);
-}
-
-/* Returns a character from the packet. */
-
-u_int
-packet_get_char(void)
-{
-	char ch;
-
-	buffer_get(&active_state->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(&active_state->incoming_packet);
-}
-
-/* Returns an 64 bit integer from the packet data. */
-
-u_int64_t
-packet_get_int64(void)
-{
-	return buffer_get_int64(&active_state->incoming_packet);
-}
-
-/*
- * Returns an arbitrary precision integer from the packet data.  The integer
- * must have been initialized before this call.
- */
-
-#ifdef WITH_OPENSSL
-void
-packet_get_bignum(BIGNUM * value)
-{
-	buffer_get_bignum(&active_state->incoming_packet, value);
-}
-
-void
-packet_get_bignum2(BIGNUM * value)
-{
-	buffer_get_bignum2(&active_state->incoming_packet, value);
-}
-
-#ifdef OPENSSL_HAS_ECC
-void
-packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point)
-{
-	buffer_get_ecpoint(&active_state->incoming_packet, curve, point);
-}
-#endif
-#endif
-
-void *
-packet_get_raw(u_int *length_ptr)
-{
-	u_int bytes = buffer_len(&active_state->incoming_packet);
-
-	if (length_ptr != NULL)
-		*length_ptr = bytes;
-	return buffer_ptr(&active_state->incoming_packet);
+	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
 }
 
 int
-packet_remaining(void)
+ssh_packet_remaining(struct ssh *ssh)
 {
-	return buffer_len(&active_state->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(&active_state->incoming_packet, length_ptr);
-}
-
-const void *
-packet_get_string_ptr(u_int *length_ptr)
-{
-	return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
-}
-
-/* Ensures the returned string has no embedded \0 characters in it. */
-char *
-packet_get_cstring(u_int *length_ptr)
-{
-	return buffer_get_cstring(&active_state->incoming_packet, length_ptr);
+	return sshbuf_len(ssh->state->incoming_packet);
 }
 
 /*
@@ -1666,12 +1820,13 @@
  */
 
 void
-packet_send_debug(const char *fmt,...)
+ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
 {
 	char buf[1024];
 	va_list args;
+	int r;
 
-	if (compat20 && (datafellows & SSH_BUG_DEBUG))
+	if (compat20 && (ssh->compat & SSH_BUG_DEBUG))
 		return;
 
 	va_start(args, fmt);
@@ -1679,16 +1834,19 @@
 	va_end(args);
 
 	if (compat20) {
-		packet_start(SSH2_MSG_DEBUG);
-		packet_put_char(0);	/* bool: always display */
-		packet_put_cstring(buf);
-		packet_put_cstring("");
+		if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
+		    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 	} else {
-		packet_start(SSH_MSG_DEBUG);
-		packet_put_cstring(buf);
+		if ((r = sshpkt_start(ssh, SSH_MSG_DEBUG)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 	}
-	packet_send();
-	packet_write_wait();
+	ssh_packet_write_wait(ssh);
 }
 
 /*
@@ -1699,11 +1857,12 @@
  */
 
 void
-packet_disconnect(const char *fmt,...)
+ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
 {
 	char buf[1024];
 	va_list args;
 	static int disconnecting = 0;
+	int r;
 
 	if (disconnecting)	/* Guard against recursive invocations. */
 		fatal("packet_disconnect called recursively.");
@@ -1722,37 +1881,38 @@
 
 	/* 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("");
+		if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 	} else {
-		packet_start(SSH_MSG_DISCONNECT);
-		packet_put_cstring(buf);
+		if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 	}
-	packet_send();
-	packet_write_wait();
-
-	/* Stop listening for connections. */
-	channel_close_all();
+	ssh_packet_write_wait(ssh);
 
 	/* Close the connection. */
-	packet_close();
+	ssh_packet_close(ssh);
 	cleanup_exit(255);
 }
 
 /* Checks if there is any buffered output, and tries to write some of the output. */
 
 void
-packet_write_poll(void)
+ssh_packet_write_poll(struct ssh *ssh)
 {
-	int len = buffer_len(&active_state->output);
-	int cont;
+	struct session_state *state = ssh->state;
+	int len = sshbuf_len(state->output);
+	int cont, r;
 
 	if (len > 0) {
 		cont = 0;
-		len = roaming_write(active_state->connection_out,
-		    buffer_ptr(&active_state->output), len, &cont);
+		len = roaming_write(state->connection_out,
+		    sshbuf_ptr(state->output), len, &cont);
 		if (len == -1) {
 			if (errno == EINTR || errno == EAGAIN ||
 			    errno == EWOULDBLOCK)
@@ -1761,7 +1921,8 @@
 		}
 		if (len == 0 && !cont)
 			fatal("Write connection closed");
-		buffer_consume(&active_state->output, len);
+		if ((r = sshbuf_consume(state->output, len)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 	}
 }
 
@@ -1771,36 +1932,39 @@
  */
 
 void
-packet_write_wait(void)
+ssh_packet_write_wait(struct ssh *ssh)
 {
 	fd_set *setp;
 	int ret, ms_remain = 0;
 	struct timeval start, timeout, *timeoutp = NULL;
+	struct session_state *state = ssh->state;
 
-	setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
+	setp = (fd_set *)calloc(howmany(state->connection_out + 1,
 	    NFDBITS), sizeof(fd_mask));
-	packet_write_poll();
-	while (packet_have_data_to_write()) {
-		memset(setp, 0, howmany(active_state->connection_out + 1,
+	if (setp == NULL)
+		fatal("%s: calloc failed", __func__);
+	ssh_packet_write_poll(ssh);
+	while (ssh_packet_have_data_to_write(ssh)) {
+		memset(setp, 0, howmany(state->connection_out + 1,
 		    NFDBITS) * sizeof(fd_mask));
-		FD_SET(active_state->connection_out, setp);
+		FD_SET(state->connection_out, setp);
 
-		if (active_state->packet_timeout_ms > 0) {
-			ms_remain = active_state->packet_timeout_ms;
+		if (state->packet_timeout_ms > 0) {
+			ms_remain = state->packet_timeout_ms;
 			timeoutp = &timeout;
 		}
 		for (;;) {
-			if (active_state->packet_timeout_ms != -1) {
+			if (state->packet_timeout_ms != -1) {
 				ms_to_timeval(&timeout, ms_remain);
 				gettimeofday(&start, NULL);
 			}
-			if ((ret = select(active_state->connection_out + 1,
+			if ((ret = select(state->connection_out + 1,
 			    NULL, setp, NULL, timeoutp)) >= 0)
 				break;
 			if (errno != EAGAIN && errno != EINTR &&
 			    errno != EWOULDBLOCK)
 				break;
-			if (active_state->packet_timeout_ms == -1)
+			if (state->packet_timeout_ms == -1)
 				continue;
 			ms_subtract_diff(&start, &ms_remain);
 			if (ms_remain <= 0) {
@@ -1810,10 +1974,10 @@
 		}
 		if (ret == 0) {
 			logit("Connection to %.200s timed out while "
-			    "waiting to write", get_remote_ipaddr());
+			    "waiting to write", ssh_remote_ipaddr(ssh));
 			cleanup_exit(255);
 		}
-		packet_write_poll();
+		ssh_packet_write_poll(ssh);
 	}
 	free(setp);
 }
@@ -1821,33 +1985,33 @@
 /* Returns true if there is buffered data to write to the connection. */
 
 int
-packet_have_data_to_write(void)
+ssh_packet_have_data_to_write(struct ssh *ssh)
 {
-	return buffer_len(&active_state->output) != 0;
+	return sshbuf_len(ssh->state->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)
+ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
 {
-	if (active_state->interactive_mode)
-		return buffer_len(&active_state->output) < 16384;
+	if (ssh->state->interactive_mode)
+		return sshbuf_len(ssh->state->output) < 16384;
 	else
-		return buffer_len(&active_state->output) < 128 * 1024;
+		return sshbuf_len(ssh->state->output) < 128 * 1024;
 }
 
-static void
-packet_set_tos(int tos)
+void
+ssh_packet_set_tos(struct ssh *ssh, int tos)
 {
 #ifndef IP_TOS_IS_BROKEN
-	if (!packet_connection_is_on_socket())
+	if (!ssh_packet_connection_is_on_socket(ssh))
 		return;
-	switch (packet_connection_af()) {
+	switch (ssh_packet_connection_af(ssh)) {
 # ifdef IP_TOS
 	case AF_INET:
 		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
-		if (setsockopt(active_state->connection_in,
+		if (setsockopt(ssh->state->connection_in,
 		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
 			error("setsockopt IP_TOS %d: %.100s:",
 			    tos, strerror(errno));
@@ -1856,7 +2020,7 @@
 # ifdef IPV6_TCLASS
 	case AF_INET6:
 		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
-		if (setsockopt(active_state->connection_in,
+		if (setsockopt(ssh->state->connection_in,
 		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
 			error("setsockopt IPV6_TCLASS %d: %.100s:",
 			    tos, strerror(errno));
@@ -1869,71 +2033,69 @@
 /* Informs that the current session is interactive.  Sets IP flags for that. */
 
 void
-packet_set_interactive(int interactive, int qos_interactive, int qos_bulk)
+ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
 {
-	if (active_state->set_interactive_called)
+	struct session_state *state = ssh->state;
+
+	if (state->set_interactive_called)
 		return;
-	active_state->set_interactive_called = 1;
+	state->set_interactive_called = 1;
 
 	/* Record that we are in interactive mode. */
-	active_state->interactive_mode = interactive;
+	state->interactive_mode = interactive;
 
 	/* Only set socket options if using a socket.  */
-	if (!packet_connection_is_on_socket())
+	if (!ssh_packet_connection_is_on_socket(ssh))
 		return;
-	set_nodelay(active_state->connection_in);
-	packet_set_tos(interactive ? qos_interactive : qos_bulk);
+	set_nodelay(state->connection_in);
+	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
+	    qos_bulk);
 }
 
 /* Returns true if the current connection is interactive. */
 
 int
-packet_is_interactive(void)
+ssh_packet_is_interactive(struct ssh *ssh)
 {
-	return active_state->interactive_mode;
+	return ssh->state->interactive_mode;
 }
 
 int
-packet_set_maxsize(u_int s)
+ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
 {
-	if (active_state->set_maxsize_called) {
+	struct session_state *state = ssh->state;
+
+	if (state->set_maxsize_called) {
 		logit("packet_set_maxsize: called twice: old %d new %d",
-		    active_state->max_packet_size, s);
+		    state->max_packet_size, s);
 		return -1;
 	}
 	if (s < 4 * 1024 || s > 1024 * 1024) {
 		logit("packet_set_maxsize: bad size %d", s);
 		return -1;
 	}
-	active_state->set_maxsize_called = 1;
+	state->set_maxsize_called = 1;
 	debug("packet_set_maxsize: setting to %d", s);
-	active_state->max_packet_size = s;
+	state->max_packet_size = s;
 	return s;
 }
 
 int
-packet_inc_alive_timeouts(void)
+ssh_packet_inc_alive_timeouts(struct ssh *ssh)
 {
-	return ++active_state->keep_alive_timeouts;
+	return ++ssh->state->keep_alive_timeouts;
 }
 
 void
-packet_set_alive_timeouts(int ka)
+ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
 {
-	active_state->keep_alive_timeouts = ka;
+	ssh->state->keep_alive_timeouts = ka;
 }
 
 u_int
-packet_get_maxsize(void)
+ssh_packet_get_maxsize(struct ssh *ssh)
 {
-	return active_state->max_packet_size;
-}
-
-/* roundup current message to pad bytes */
-void
-packet_add_padding(u_char pad)
-{
-	active_state->extra_pad = pad;
+	return ssh->state->max_packet_size;
 }
 
 /*
@@ -1948,155 +2110,702 @@
  * protection measure against advanced traffic analysis techniques.
  */
 void
-packet_send_ignore(int nbytes)
+ssh_packet_send_ignore(struct ssh *ssh, int nbytes)
 {
 	u_int32_t rnd = 0;
-	int i;
+	int r, i;
 
-	packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
-	packet_put_int(nbytes);
+	if ((r = sshpkt_start(ssh, compat20 ?
+	    SSH2_MSG_IGNORE : SSH_MSG_IGNORE)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
 	for (i = 0; i < nbytes; i++) {
 		if (i % 4 == 0)
 			rnd = arc4random();
-		packet_put_char((u_char)rnd & 0xff);
+		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
 		rnd >>= 8;
 	}
 }
 
 #define MAX_PACKETS	(1U<<31)
 int
-packet_need_rekeying(void)
+ssh_packet_need_rekeying(struct ssh *ssh)
 {
-	if (datafellows & SSH_BUG_NOREKEY)
+	struct session_state *state = ssh->state;
+
+	if (ssh->compat & SSH_BUG_NOREKEY)
 		return 0;
 	return
-	    (active_state->p_send.packets > MAX_PACKETS) ||
-	    (active_state->p_read.packets > MAX_PACKETS) ||
-	    (active_state->max_blocks_out &&
-	        (active_state->p_send.blocks > active_state->max_blocks_out)) ||
-	    (active_state->max_blocks_in &&
-	        (active_state->p_read.blocks > active_state->max_blocks_in)) ||
-	    (active_state->rekey_interval != 0 && active_state->rekey_time +
-		 active_state->rekey_interval <= monotime());
+	    (state->p_send.packets > MAX_PACKETS) ||
+	    (state->p_read.packets > MAX_PACKETS) ||
+	    (state->max_blocks_out &&
+	        (state->p_send.blocks > state->max_blocks_out)) ||
+	    (state->max_blocks_in &&
+	        (state->p_read.blocks > state->max_blocks_in)) ||
+	    (state->rekey_interval != 0 && state->rekey_time +
+		 state->rekey_interval <= monotime());
 }
 
 void
-packet_set_rekey_limits(u_int32_t bytes, time_t seconds)
+ssh_packet_set_rekey_limits(struct ssh *ssh, u_int32_t bytes, time_t seconds)
 {
 	debug3("rekey after %lld bytes, %d seconds", (long long)bytes,
 	    (int)seconds);
-	active_state->rekey_limit = bytes;
-	active_state->rekey_interval = seconds;
+	ssh->state->rekey_limit = bytes;
+	ssh->state->rekey_interval = seconds;
 	/*
 	 * We set the time here so that in post-auth privsep slave we count
 	 * from the completion of the authentication.
 	 */
-	active_state->rekey_time = monotime();
+	ssh->state->rekey_time = monotime();
 }
 
 time_t
-packet_get_rekey_timeout(void)
+ssh_packet_get_rekey_timeout(struct ssh *ssh)
 {
 	time_t seconds;
 
-	seconds = active_state->rekey_time + active_state->rekey_interval -
+	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
 	    monotime();
 	return (seconds <= 0 ? 1 : seconds);
 }
 
 void
-packet_set_server(void)
+ssh_packet_set_server(struct ssh *ssh)
 {
-	active_state->server_side = 1;
+	ssh->state->server_side = 1;
 }
 
 void
-packet_set_authenticated(void)
+ssh_packet_set_authenticated(struct ssh *ssh)
 {
-	active_state->after_authentication = 1;
+	ssh->state->after_authentication = 1;
 }
 
 void *
-packet_get_input(void)
+ssh_packet_get_input(struct ssh *ssh)
 {
-	return (void *)&active_state->input;
+	return (void *)ssh->state->input;
 }
 
 void *
-packet_get_output(void)
+ssh_packet_get_output(struct ssh *ssh)
 {
-	return (void *)&active_state->output;
+	return (void *)ssh->state->output;
 }
 
-void *
-packet_get_newkeys(int mode)
-{
-	return (void *)active_state->newkeys[mode];
-}
-
+/* XXX TODO update roaming to new API (does not work anyway) */
 /*
  * Save the state for the real connection, and use a separate state when
  * resuming a suspended connection.
  */
 void
-packet_backup_state(void)
+ssh_packet_backup_state(struct ssh *ssh,
+    struct ssh *backup_state)
 {
-	struct session_state *tmp;
+	struct ssh *tmp;
 
-	close(active_state->connection_in);
-	active_state->connection_in = -1;
-	close(active_state->connection_out);
-	active_state->connection_out = -1;
+	close(ssh->state->connection_in);
+	ssh->state->connection_in = -1;
+	close(ssh->state->connection_out);
+	ssh->state->connection_out = -1;
 	if (backup_state)
 		tmp = backup_state;
 	else
-		tmp = alloc_session_state();
-	backup_state = active_state;
-	active_state = tmp;
+		tmp = ssh_alloc_session_state();
+	backup_state = ssh;
+	ssh = tmp;
 }
 
+/* XXX FIXME FIXME FIXME */
 /*
  * Swap in the old state when resuming a connecion.
  */
 void
-packet_restore_state(void)
+ssh_packet_restore_state(struct ssh *ssh,
+    struct ssh *backup_state)
 {
-	struct session_state *tmp;
-	void *buf;
+	struct ssh *tmp;
 	u_int len;
+	int r;
 
 	tmp = backup_state;
-	backup_state = active_state;
-	active_state = tmp;
-	active_state->connection_in = backup_state->connection_in;
-	backup_state->connection_in = -1;
-	active_state->connection_out = backup_state->connection_out;
-	backup_state->connection_out = -1;
-	len = buffer_len(&backup_state->input);
+	backup_state = ssh;
+	ssh = tmp;
+	ssh->state->connection_in = backup_state->state->connection_in;
+	backup_state->state->connection_in = -1;
+	ssh->state->connection_out = backup_state->state->connection_out;
+	backup_state->state->connection_out = -1;
+	len = sshbuf_len(backup_state->state->input);
 	if (len > 0) {
-		buf = buffer_ptr(&backup_state->input);
-		buffer_append(&active_state->input, buf, len);
-		buffer_clear(&backup_state->input);
+		if ((r = sshbuf_putb(ssh->state->input,
+		    backup_state->state->input)) != 0)
+			fatal("%s: %s", __func__, ssh_err(r));
+		sshbuf_reset(backup_state->state->input);
 		add_recv_bytes(len);
 	}
 }
 
 /* Reset after_authentication and reset compression in post-auth privsep */
-void
-packet_set_postauth(void)
+static int
+ssh_packet_set_postauth(struct ssh *ssh)
 {
-	Comp *comp;
-	int mode;
+	struct sshcomp *comp;
+	int r, mode;
 
 	debug("%s: called", __func__);
 	/* This was set in net child, but is not visible in user child */
-	active_state->after_authentication = 1;
-	active_state->rekeying = 0;
+	ssh->state->after_authentication = 1;
+	ssh->state->rekeying = 0;
 	for (mode = 0; mode < MODE_MAX; mode++) {
-		if (active_state->newkeys[mode] == NULL)
+		if (ssh->state->newkeys[mode] == NULL)
 			continue;
-		comp = &active_state->newkeys[mode]->comp;
-		if (comp && comp->enabled)
-			packet_init_compression();
+		comp = &ssh->state->newkeys[mode]->comp;
+		if (comp && comp->enabled &&
+		    (r = ssh_packet_init_compression(ssh)) != 0)
+			return r;
 	}
+	return 0;
+}
+
+/* Packet state (de-)serialization for privsep */
+
+/* turn kex into a blob for packet state serialization */
+static int
+kex_to_blob(struct sshbuf *m, struct kex *kex)
+{
+	int r;
+
+	if ((r = sshbuf_put_string(m, kex->session_id,
+	    kex->session_id_len)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
+	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
+	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->flags)) != 0 ||
+	    (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 ||
+	    (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0)
+		return r;
+	return 0;
+}
+
+/* turn key exchange results into a blob for packet state serialization */
+static int
+newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
+{
+	struct sshbuf *b;
+	struct sshcipher_ctx *cc;
+	struct sshcomp *comp;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct newkeys *newkey;
+	int r;
+
+	if ((newkey = ssh->state->newkeys[mode]) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	enc = &newkey->enc;
+	mac = &newkey->mac;
+	comp = &newkey->comp;
+	cc = (mode == MODE_OUT) ? &ssh->state->send_context :
+	    &ssh->state->receive_context;
+	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
+		return r;
+	if ((b = sshbuf_new()) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	/* The cipher struct is constant and shared, you export pointer */
+	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
+	    (r = sshbuf_put(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
+	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
+	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
+	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
+	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
+		goto out;
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
+		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
+		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
+			goto out;
+	}
+	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
+	    (r = sshbuf_put_u32(b, comp->enabled)) != 0 ||
+	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
+		goto out;
+	r = sshbuf_put_stringb(m, b);
+ out:
+	if (b != NULL)
+		sshbuf_free(b);
+	return r;
+}
+
+/* serialize packet state into a blob */
+int
+ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
+{
+	struct session_state *state = ssh->state;
+	u_char *p;
+	size_t slen, rlen;
+	int r, ssh1cipher;
+
+	if (!compat20) {
+		ssh1cipher = cipher_get_number(state->receive_context.cipher);
+		slen = cipher_get_keyiv_len(&state->send_context);
+		rlen = cipher_get_keyiv_len(&state->receive_context);
+		if ((r = sshbuf_put_u32(m, state->remote_protocol_flags)) != 0 ||
+		    (r = sshbuf_put_u32(m, ssh1cipher)) != 0 ||
+		    (r = sshbuf_put_string(m, state->ssh1_key, state->ssh1_keylen)) != 0 ||
+		    (r = sshbuf_put_u32(m, slen)) != 0 ||
+		    (r = sshbuf_reserve(m, slen, &p)) != 0 ||
+		    (r = cipher_get_keyiv(&state->send_context, p, slen)) != 0 ||
+		    (r = sshbuf_put_u32(m, rlen)) != 0 ||
+		    (r = sshbuf_reserve(m, rlen, &p)) != 0 ||
+		    (r = cipher_get_keyiv(&state->receive_context, p, rlen)) != 0)
+			return r;
+	} else {
+		if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
+		    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
+		    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
+		    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
+		    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
+		    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
+		    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
+		    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
+		    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
+		    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
+		    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0)
+			return r;
+	}
+
+	slen = cipher_get_keycontext(&state->send_context, NULL);
+	rlen = cipher_get_keycontext(&state->receive_context, NULL);
+	if ((r = sshbuf_put_u32(m, slen)) != 0 ||
+	    (r = sshbuf_reserve(m, slen, &p)) != 0)
+		return r;
+	if (cipher_get_keycontext(&state->send_context, p) != (int)slen)
+		return SSH_ERR_INTERNAL_ERROR;
+	if ((r = sshbuf_put_u32(m, rlen)) != 0 ||
+	    (r = sshbuf_reserve(m, rlen, &p)) != 0)
+		return r;
+	if (cipher_get_keycontext(&state->receive_context, p) != (int)rlen)
+		return SSH_ERR_INTERNAL_ERROR;
+
+	if ((r = ssh_packet_get_compress_state(m, ssh)) != 0 ||
+	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
+	    (r = sshbuf_put_stringb(m, state->output)) != 0)
+		return r;
+
+	if (compat20) {
+		if ((r = sshbuf_put_u64(m, get_sent_bytes())) != 0 ||
+		    (r = sshbuf_put_u64(m, get_recv_bytes())) != 0)
+			return r;
+	}
+	return 0;
+}
+
+/* restore key exchange results from blob for packet state de-serialization */
+static int
+newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
+{
+	struct sshbuf *b = NULL;
+	struct sshcomp *comp;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct newkeys *newkey = NULL;
+	size_t keylen, ivlen, maclen;
+	int r;
+
+	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshbuf_froms(m, &b)) != 0)
+		goto out;
+#ifdef DEBUG_PK
+	sshbuf_dump(b, stderr);
+#endif
+	enc = &newkey->enc;
+	mac = &newkey->mac;
+	comp = &newkey->comp;
+
+	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
+	    (r = sshbuf_get(b, &enc->cipher, sizeof(enc->cipher))) != 0 ||
+	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
+	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
+	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
+	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
+		goto out;
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
+			goto out;
+		if ((r = mac_setup(mac, mac->name)) != 0)
+			goto out;
+		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
+		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
+			goto out;
+		if (maclen > mac->key_len) {
+			r = SSH_ERR_INVALID_FORMAT;
+			goto out;
+		}
+		mac->key_len = maclen;
+	}
+	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
+	    (r = sshbuf_get_u32(b, (u_int *)&comp->enabled)) != 0 ||
+	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
+		goto out;
+	if (enc->name == NULL ||
+	    cipher_by_name(enc->name) != enc->cipher) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	if (sshbuf_len(b) != 0) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	enc->key_len = keylen;
+	enc->iv_len = ivlen;
+	ssh->kex->newkeys[mode] = newkey;
+	newkey = NULL;
+	r = 0;
+ out:
+	if (newkey != NULL)
+		free(newkey);
+	if (b != NULL)
+		sshbuf_free(b);
+	return r;
+}
+
+/* restore kex from blob for packet state de-serialization */
+static int
+kex_from_blob(struct sshbuf *m, struct kex **kexp)
+{
+	struct kex *kex;
+	int r;
+
+	if ((kex = calloc(1, sizeof(struct kex))) == NULL ||
+	    (kex->my = sshbuf_new()) == NULL ||
+	    (kex->peer = sshbuf_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
+	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
+	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
+	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->flags)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0)
+		goto out;
+	kex->server = 1;
+	kex->done = 1;
+	r = 0;
+ out:
+	if (r != 0 || kexp == NULL) {
+		if (kex != NULL) {
+			if (kex->my != NULL)
+				sshbuf_free(kex->my);
+			if (kex->peer != NULL)
+				sshbuf_free(kex->peer);
+			free(kex);
+		}
+		if (kexp != NULL)
+			*kexp = NULL;
+	} else {
+		*kexp = kex;
+	}
+	return r;
+}
+
+/*
+ * Restore packet state from content of blob 'm' (de-serialization).
+ * Note that 'm' will be partially consumed on parsing or any other errors.
+ */
+int
+ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
+{
+	struct session_state *state = ssh->state;
+	const u_char *ssh1key, *ivin, *ivout, *keyin, *keyout, *input, *output;
+	size_t ssh1keylen, rlen, slen, ilen, olen;
+	int r;
+	u_int ssh1cipher = 0;
+	u_int64_t sent_bytes = 0, recv_bytes = 0;
+
+	if (!compat20) {
+		if ((r = sshbuf_get_u32(m, &state->remote_protocol_flags)) != 0 ||
+		    (r = sshbuf_get_u32(m, &ssh1cipher)) != 0 ||
+		    (r = sshbuf_get_string_direct(m, &ssh1key, &ssh1keylen)) != 0 ||
+		    (r = sshbuf_get_string_direct(m, &ivout, &slen)) != 0 ||
+		    (r = sshbuf_get_string_direct(m, &ivin, &rlen)) != 0)
+			return r;
+		if (ssh1cipher > INT_MAX)
+			return SSH_ERR_KEY_UNKNOWN_CIPHER;
+		ssh_packet_set_encryption_key(ssh, ssh1key, ssh1keylen,
+		    (int)ssh1cipher);
+		if (cipher_get_keyiv_len(&state->send_context) != (int)slen ||
+		    cipher_get_keyiv_len(&state->receive_context) != (int)rlen)
+			return SSH_ERR_INVALID_FORMAT;
+		if ((r = cipher_set_keyiv(&state->send_context, ivout)) != 0 ||
+		    (r = cipher_set_keyiv(&state->receive_context, ivin)) != 0)
+			return r;
+	} else {
+		if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
+		    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
+		    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
+		    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
+		    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
+		    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
+		    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
+		    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
+		    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
+		    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
+		    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
+			return r;
+		/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
+		if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
+		    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
+			return r;
+	}
+	if ((r = sshbuf_get_string_direct(m, &keyout, &slen)) != 0 ||
+	    (r = sshbuf_get_string_direct(m, &keyin, &rlen)) != 0)
+		return r;
+	if (cipher_get_keycontext(&state->send_context, NULL) != (int)slen ||
+	    cipher_get_keycontext(&state->receive_context, NULL) != (int)rlen)
+		return SSH_ERR_INVALID_FORMAT;
+	cipher_set_keycontext(&state->send_context, keyout);
+	cipher_set_keycontext(&state->receive_context, keyin);
+
+	if ((r = ssh_packet_set_compress_state(ssh, m)) != 0 ||
+	    (r = ssh_packet_set_postauth(ssh)) != 0)
+		return r;
+
+	sshbuf_reset(state->input);
+	sshbuf_reset(state->output);
+	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
+	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
+	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
+	    (r = sshbuf_put(state->output, output, olen)) != 0)
+		return r;
+
+	if (compat20) {
+		if ((r = sshbuf_get_u64(m, &sent_bytes)) != 0 ||
+		    (r = sshbuf_get_u64(m, &recv_bytes)) != 0)
+			return r;
+		roam_set_bytes(sent_bytes, recv_bytes);
+	}
+	if (sshbuf_len(m))
+		return SSH_ERR_INVALID_FORMAT;
+	debug3("%s: done", __func__);
+	return 0;
+}
+
+/* NEW API */
+
+/* put data to the outgoing packet */
+
+int
+sshpkt_put(struct ssh *ssh, const void *v, size_t len)
+{
+	return sshbuf_put(ssh->state->outgoing_packet, v, len);
+}
+
+int
+sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
+{
+	return sshbuf_putb(ssh->state->outgoing_packet, b);
+}
+
+int
+sshpkt_put_u8(struct ssh *ssh, u_char val)
+{
+	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
+{
+	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
+{
+	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
+{
+	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
+}
+
+int
+sshpkt_put_cstring(struct ssh *ssh, const void *v)
+{
+	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
+}
+
+int
+sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
+{
+	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
+}
+
+int
+sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
+{
+	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
+}
+
+int
+sshpkt_put_bignum1(struct ssh *ssh, const BIGNUM *v)
+{
+	return sshbuf_put_bignum1(ssh->state->outgoing_packet, v);
+}
+
+int
+sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
+{
+	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
+}
+
+/* fetch data from the incoming packet */
+
+int
+sshpkt_get(struct ssh *ssh, void *valp, size_t len)
+{
+	return sshbuf_get(ssh->state->incoming_packet, valp, len);
+}
+
+int
+sshpkt_get_u8(struct ssh *ssh, u_char *valp)
+{
+	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
+{
+	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
+{
+	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
+{
+	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
+{
+	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
+{
+	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
+{
+	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
+}
+
+int
+sshpkt_get_bignum1(struct ssh *ssh, BIGNUM *v)
+{
+	return sshbuf_get_bignum1(ssh->state->incoming_packet, v);
+}
+
+int
+sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v)
+{
+	return sshbuf_get_bignum2(ssh->state->incoming_packet, v);
+}
+
+int
+sshpkt_get_end(struct ssh *ssh)
+{
+	if (sshbuf_len(ssh->state->incoming_packet) > 0)
+		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
+	return 0;
+}
+
+const u_char *
+sshpkt_ptr(struct ssh *ssh, size_t *lenp)
+{
+	if (lenp != NULL)
+		*lenp = sshbuf_len(ssh->state->incoming_packet);
+	return sshbuf_ptr(ssh->state->incoming_packet);
+}
+
+/* start a new packet */
+
+int
+sshpkt_start(struct ssh *ssh, 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;
+	sshbuf_reset(ssh->state->outgoing_packet);
+	return sshbuf_put(ssh->state->outgoing_packet, buf, len);
+}
+
+/* send it */
+
+int
+sshpkt_send(struct ssh *ssh)
+{
+	if (compat20)
+		return ssh_packet_send2(ssh);
+	else
+		return ssh_packet_send1(ssh);
+}
+
+int
+sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
+{
+	char buf[1024];
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	if (compat20) {
+		if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			return r;
+	} else {
+		if ((r = sshpkt_start(ssh, SSH_MSG_DISCONNECT)) != 0 ||
+		    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			return r;
+	}
+	return 0;
+}
+
+/* roundup current message to pad bytes */
+int
+sshpkt_add_padding(struct ssh *ssh, u_char pad)
+{
+	ssh->state->extra_pad = pad;
+	return 0;
 }