Merge upstream-master into master

Commit ecb2c02d994b3e21994f31a70ff911667c262f1f upstream

This nearly (but not quite) corresponds to V_8_3_P1; subsequent
cherry-picks will correct this.

Bug: 162492243
Change-Id: I3c079d86435b7c25aefff4538dc89a3002b1e25b

1 files changed, 447 insertions, 521 deletions

diff --git a/monitor_wrap.c b/monitor_wrap.c
index b379f055..001a8fa1 100644
--- a/monitor_wrap.c
+++ b/monitor_wrap.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: monitor_wrap.c,v 1.84 2015/02/16 22:13:32 djm Exp $ */
+/* $OpenBSD: monitor_wrap.c,v 1.117 2019/12/15 18:57:30 djm Exp $ */
 /*
  * Copyright 2002 Niels Provos <provos@citi.umich.edu>
  * Copyright 2002 Markus Friedl <markus@openbsd.org>
@@ -50,8 +50,8 @@
 #ifdef WITH_OPENSSL
 #include "dh.h"
 #endif
-#include "buffer.h"
-#include "key.h"
+#include "sshbuf.h"
+#include "sshkey.h"
 #include "cipher.h"
 #include "kex.h"
 #include "hostfile.h"
@@ -60,13 +60,7 @@
 #include "packet.h"
 #include "mac.h"
 #include "log.h"
-#ifdef TARGET_OS_MAC    /* XXX Broken krb5 headers on Mac */
-#undef TARGET_OS_MAC
-#include "zlib.h"
-#define TARGET_OS_MAC 1
-#else
-#include "zlib.h"
-#endif
+#include "auth-pam.h"
 #include "monitor.h"
 #ifdef GSSAPI
 #include "ssh-gss.h"
@@ -75,47 +69,43 @@
 #include "atomicio.h"
 #include "monitor_fdpass.h"
 #include "misc.h"
-#include "uuencode.h"
 
 #include "channels.h"
 #include "session.h"
 #include "servconf.h"
-#include "roaming.h"
 
 #include "ssherr.h"
 
 /* Imports */
-extern int compat20;
-extern z_stream incoming_stream;
-extern z_stream outgoing_stream;
 extern struct monitor *pmonitor;
-extern Buffer loginmsg;
+extern struct sshbuf *loginmsg;
 extern ServerOptions options;
 
 void
 mm_log_handler(LogLevel level, const char *msg, void *ctx)
 {
-	Buffer log_msg;
+	struct sshbuf *log_msg;
 	struct monitor *mon = (struct monitor *)ctx;
+	int r;
+	size_t len;
 
 	if (mon->m_log_sendfd == -1)
 		fatal("%s: no log channel", __func__);
 
-	buffer_init(&log_msg);
-	/*
-	 * Placeholder for packet length. Will be filled in with the actual
-	 * packet length once the packet has been constucted. This saves
-	 * fragile math.
-	 */
-	buffer_put_int(&log_msg, 0);
+	if ((log_msg = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
 
-	buffer_put_int(&log_msg, level);
-	buffer_put_cstring(&log_msg, msg);
-	put_u32(buffer_ptr(&log_msg), buffer_len(&log_msg) - 4);
-	if (atomicio(vwrite, mon->m_log_sendfd, buffer_ptr(&log_msg),
-	    buffer_len(&log_msg)) != buffer_len(&log_msg))
+	if ((r = sshbuf_put_u32(log_msg, 0)) != 0 || /* length; filled below */
+	    (r = sshbuf_put_u32(log_msg, level)) != 0 ||
+	    (r = sshbuf_put_cstring(log_msg, msg)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if ((len = sshbuf_len(log_msg)) < 4 || len > 0xffffffff)
+		fatal("%s: bad length %zu", __func__, len);
+	POKE_U32(sshbuf_mutable_ptr(log_msg), len - 4);
+	if (atomicio(vwrite, mon->m_log_sendfd,
+	    sshbuf_mutable_ptr(log_msg), len) != len)
 		fatal("%s: write: %s", __func__, strerror(errno));
-	buffer_free(&log_msg);
+	sshbuf_free(log_msg);
 }
 
 int
@@ -129,54 +119,58 @@ mm_is_monitor(void)
 }
 
 void
-mm_request_send(int sock, enum monitor_reqtype type, Buffer *m)
+mm_request_send(int sock, enum monitor_reqtype type, struct sshbuf *m)
 {
-	u_int mlen = buffer_len(m);
+	size_t mlen = sshbuf_len(m);
 	u_char buf[5];
 
 	debug3("%s entering: type %d", __func__, type);
 
-	put_u32(buf, mlen + 1);
+	if (mlen >= 0xffffffff)
+		fatal("%s: bad length %zu", __func__, mlen);
+	POKE_U32(buf, mlen + 1);
 	buf[4] = (u_char) type;		/* 1st byte of payload is mesg-type */
 	if (atomicio(vwrite, sock, buf, sizeof(buf)) != sizeof(buf))
 		fatal("%s: write: %s", __func__, strerror(errno));
-	if (atomicio(vwrite, sock, buffer_ptr(m), mlen) != mlen)
+	if (atomicio(vwrite, sock, sshbuf_mutable_ptr(m), mlen) != mlen)
 		fatal("%s: write: %s", __func__, strerror(errno));
 }
 
 void
-mm_request_receive(int sock, Buffer *m)
+mm_request_receive(int sock, struct sshbuf *m)
 {
-	u_char buf[4];
+	u_char buf[4], *p = NULL;
 	u_int msg_len;
+	int r;
 
 	debug3("%s entering", __func__);
 
 	if (atomicio(read, sock, buf, sizeof(buf)) != sizeof(buf)) {
-		if (errno == EPIPE) {
-			error("%s: socket closed", __func__);
+		if (errno == EPIPE)
 			cleanup_exit(255);
-		}
 		fatal("%s: read: %s", __func__, strerror(errno));
 	}
-	msg_len = get_u32(buf);
+	msg_len = PEEK_U32(buf);
 	if (msg_len > 256 * 1024)
 		fatal("%s: read: bad msg_len %d", __func__, msg_len);
-	buffer_clear(m);
-	buffer_append_space(m, msg_len);
-	if (atomicio(read, sock, buffer_ptr(m), msg_len) != msg_len)
+	sshbuf_reset(m);
+	if ((r = sshbuf_reserve(m, msg_len, &p)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (atomicio(read, sock, p, msg_len) != msg_len)
 		fatal("%s: read: %s", __func__, strerror(errno));
 }
 
 void
-mm_request_receive_expect(int sock, enum monitor_reqtype type, Buffer *m)
+mm_request_receive_expect(int sock, enum monitor_reqtype type, struct sshbuf *m)
 {
 	u_char rtype;
+	int r;
 
 	debug3("%s entering: type %d", __func__, type);
 
 	mm_request_receive(sock, m);
-	rtype = buffer_get_char(m);
+	if ((r = sshbuf_get_u8(m, &rtype)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (rtype != type)
 		fatal("%s: read: rtype %d != type %d", __func__,
 		    rtype, type);
@@ -187,109 +181,145 @@ DH *
 mm_choose_dh(int min, int nbits, int max)
 {
 	BIGNUM *p, *g;
-	int success = 0;
-	Buffer m;
+	int r;
+	u_char success = 0;
+	struct sshbuf *m;
 
-	buffer_init(&m);
-	buffer_put_int(&m, min);
-	buffer_put_int(&m, nbits);
-	buffer_put_int(&m, max);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_u32(m, min)) != 0 ||
+	    (r = sshbuf_put_u32(m, nbits)) != 0 ||
+	    (r = sshbuf_put_u32(m, max)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_MODULI, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_MODULI, m);
 
 	debug3("%s: waiting for MONITOR_ANS_MODULI", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_MODULI, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_MODULI, m);
 
-	success = buffer_get_char(&m);
+	if ((r = sshbuf_get_u8(m, &success)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (success == 0)
 		fatal("%s: MONITOR_ANS_MODULI failed", __func__);
 
-	if ((p = BN_new()) == NULL)
-		fatal("%s: BN_new failed", __func__);
-	if ((g = BN_new()) == NULL)
-		fatal("%s: BN_new failed", __func__);
-	buffer_get_bignum2(&m, p);
-	buffer_get_bignum2(&m, g);
+	if ((r = sshbuf_get_bignum2(m, &p)) != 0 ||
+	    (r = sshbuf_get_bignum2(m, &g)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	debug3("%s: remaining %d", __func__, buffer_len(&m));
-	buffer_free(&m);
+	debug3("%s: remaining %zu", __func__, sshbuf_len(m));
+	sshbuf_free(m);
 
 	return (dh_new_group(g, p));
 }
 #endif
 
 int
-mm_key_sign(Key *key, u_char **sigp, u_int *lenp,
-    const u_char *data, u_int datalen)
+mm_sshkey_sign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp,
+    const u_char *data, size_t datalen, const char *hostkey_alg,
+    const char *sk_provider, u_int compat)
 {
 	struct kex *kex = *pmonitor->m_pkex;
-	Buffer m;
+	struct sshbuf *m;
+	u_int ndx = kex->host_key_index(key, 0, ssh);
+	int r;
 
 	debug3("%s entering", __func__);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_u32(m, ndx)) != 0 ||
+	    (r = sshbuf_put_string(m, data, datalen)) != 0 ||
+	    (r = sshbuf_put_cstring(m, hostkey_alg)) != 0 ||
+	    (r = sshbuf_put_u32(m, compat)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	buffer_init(&m);
-	buffer_put_int(&m, kex->host_key_index(key, 0, active_state));
-	buffer_put_string(&m, data, datalen);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SIGN, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SIGN, m);
 
 	debug3("%s: waiting for MONITOR_ANS_SIGN", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SIGN, &m);
-	*sigp  = buffer_get_string(&m, lenp);
-	buffer_free(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SIGN, m);
+	if ((r = sshbuf_get_string(m, sigp, lenp)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 
 	return (0);
 }
 
 struct passwd *
-mm_getpwnamallow(const char *username)
+mm_getpwnamallow(struct ssh *ssh, const char *username)
 {
-	Buffer m;
+	struct sshbuf *m;
 	struct passwd *pw;
-	u_int len, i;
+	size_t len;
+	u_int i;
 	ServerOptions *newopts;
+	int r;
+	u_char ok;
+	const u_char *p;
 
 	debug3("%s entering", __func__);
 
-	buffer_init(&m);
-	buffer_put_cstring(&m, username);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, username)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PWNAM, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PWNAM, m);
 
 	debug3("%s: waiting for MONITOR_ANS_PWNAM", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PWNAM, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PWNAM, m);
 
-	if (buffer_get_char(&m) == 0) {
+	if ((r = sshbuf_get_u8(m, &ok)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (ok == 0) {
 		pw = NULL;
 		goto out;
 	}
-	pw = buffer_get_string(&m, &len);
-	if (len != sizeof(struct passwd))
+
+	/* XXX don't like passing struct passwd like this */
+	pw = xcalloc(sizeof(*pw), 1);
+	if ((r = sshbuf_get_string_direct(m, &p, &len)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (len != sizeof(*pw))
 		fatal("%s: struct passwd size mismatch", __func__);
-	pw->pw_name = buffer_get_string(&m, NULL);
-	pw->pw_passwd = buffer_get_string(&m, NULL);
+	memcpy(pw, p, sizeof(*pw));
+
+	if ((r = sshbuf_get_cstring(m, &pw->pw_name, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &pw->pw_passwd, NULL)) != 0 ||
 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
-	pw->pw_gecos = buffer_get_string(&m, NULL);
+	    (r = sshbuf_get_cstring(m, &pw->pw_gecos, NULL)) != 0 ||
 #endif
 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
-	pw->pw_class = buffer_get_string(&m, NULL);
+	    (r = sshbuf_get_cstring(m, &pw->pw_class, NULL)) != 0 ||
 #endif
-	pw->pw_dir = buffer_get_string(&m, NULL);
-	pw->pw_shell = buffer_get_string(&m, NULL);
+	    (r = sshbuf_get_cstring(m, &pw->pw_dir, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &pw->pw_shell, NULL)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
 out:
 	/* copy options block as a Match directive may have changed some */
-	newopts = buffer_get_string(&m, &len);
+	if ((r = sshbuf_get_string_direct(m, &p, &len)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (len != sizeof(*newopts))
 		fatal("%s: option block size mismatch", __func__);
+	newopts = xcalloc(sizeof(*newopts), 1);
+	memcpy(newopts, p, sizeof(*newopts));
 
 #define M_CP_STROPT(x) do { \
-		if (newopts->x != NULL) \
-			newopts->x = buffer_get_string(&m, NULL); \
+		if (newopts->x != NULL) { \
+			if ((r = sshbuf_get_cstring(m, \
+			    &newopts->x, NULL)) != 0) \
+				fatal("%s: buffer error: %s", \
+				    __func__, ssh_err(r)); \
+		} \
 	} while (0)
 #define M_CP_STRARRAYOPT(x, nx) do { \
-		for (i = 0; i < newopts->nx; i++) \
-			newopts->x[i] = buffer_get_string(&m, NULL); \
+		newopts->x = newopts->nx == 0 ? \
+		    NULL : xcalloc(newopts->nx, sizeof(*newopts->x)); \
+		for (i = 0; i < newopts->nx; i++) { \
+			if ((r = sshbuf_get_cstring(m, \
+			    &newopts->x[i], NULL)) != 0) \
+				fatal("%s: buffer error: %s", \
+				    __func__, ssh_err(r)); \
+		} \
 	} while (0)
 	/* See comment in servconf.h */
 	COPY_MATCH_STRING_OPTS();
@@ -297,9 +327,11 @@ out:
 #undef M_CP_STRARRAYOPT
 
 	copy_set_server_options(&options, newopts, 1);
+	log_change_level(options.log_level);
+	process_permitopen(ssh, &options);
 	free(newopts);
 
-	buffer_free(&m);
+	sshbuf_free(m);
 
 	return (pw);
 }
@@ -307,19 +339,22 @@ out:
 char *
 mm_auth2_read_banner(void)
 {
-	Buffer m;
+	struct sshbuf *m;
 	char *banner;
+	int r;
 
 	debug3("%s entering", __func__);
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTH2_READ_BANNER, &m);
-	buffer_clear(&m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTH2_READ_BANNER, m);
+	sshbuf_reset(m);
 
 	mm_request_receive_expect(pmonitor->m_recvfd,
-	    MONITOR_ANS_AUTH2_READ_BANNER, &m);
-	banner = buffer_get_string(&m, NULL);
-	buffer_free(&m);
+	    MONITOR_ANS_AUTH2_READ_BANNER, m);
+	if ((r = sshbuf_get_cstring(m, &banner, NULL)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 
 	/* treat empty banner as missing banner */
 	if (strlen(banner) == 0) {
@@ -334,38 +369,55 @@ mm_auth2_read_banner(void)
 void
 mm_inform_authserv(char *service, char *style)
 {
-	Buffer m;
+	struct sshbuf *m;
+	int r;
 
 	debug3("%s entering", __func__);
 
-	buffer_init(&m);
-	buffer_put_cstring(&m, service);
-	buffer_put_cstring(&m, style ? style : "");
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, service)) != 0 ||
+	    (r = sshbuf_put_cstring(m, style ? style : "")) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHSERV, m);
 
-	buffer_free(&m);
+	sshbuf_free(m);
 }
 
 /* Do the password authentication */
 int
-mm_auth_password(Authctxt *authctxt, char *password)
+mm_auth_password(struct ssh *ssh, char *password)
 {
-	Buffer m;
-	int authenticated = 0;
+	struct sshbuf *m;
+	int r, authenticated = 0;
+#ifdef USE_PAM
+	u_int maxtries = 0;
+#endif
 
 	debug3("%s entering", __func__);
 
-	buffer_init(&m);
-	buffer_put_cstring(&m, password);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHPASSWORD, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, password)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUTHPASSWORD, m);
 
 	debug3("%s: waiting for MONITOR_ANS_AUTHPASSWORD", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_AUTHPASSWORD, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_AUTHPASSWORD, m);
 
-	authenticated = buffer_get_int(&m);
+	if ((r = sshbuf_get_u32(m, &authenticated)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+#ifdef USE_PAM
+	if ((r = sshbuf_get_u32(m, &maxtries)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (maxtries > INT_MAX)
+		fatal("%s: bad maxtries %u", __func__, maxtries);
+	sshpam_set_maxtries_reached(maxtries);
+#endif
 
-	buffer_free(&m);
+	sshbuf_free(m);
 
 	debug3("%s: user %sauthenticated",
 	    __func__, authenticated ? "" : "not ");
@@ -373,66 +425,64 @@ mm_auth_password(Authctxt *authctxt, char *password)
 }
 
 int
-mm_user_key_allowed(struct passwd *pw, Key *key)
-{
-	return (mm_key_allowed(MM_USERKEY, NULL, NULL, key));
-}
-
-int
-mm_hostbased_key_allowed(struct passwd *pw, char *user, char *host,
-    Key *key)
+mm_user_key_allowed(struct ssh *ssh, struct passwd *pw, struct sshkey *key,
+    int pubkey_auth_attempt, struct sshauthopt **authoptp)
 {
-	return (mm_key_allowed(MM_HOSTKEY, user, host, key));
+	return (mm_key_allowed(MM_USERKEY, NULL, NULL, key,
+	    pubkey_auth_attempt, authoptp));
 }
 
 int
-mm_auth_rhosts_rsa_key_allowed(struct passwd *pw, char *user,
-    char *host, Key *key)
+mm_hostbased_key_allowed(struct ssh *ssh, struct passwd *pw,
+    const char *user, const char *host, struct sshkey *key)
 {
-	int ret;
-
-	key->type = KEY_RSA; /* XXX hack for key_to_blob */
-	ret = mm_key_allowed(MM_RSAHOSTKEY, user, host, key);
-	key->type = KEY_RSA1;
-	return (ret);
+	return (mm_key_allowed(MM_HOSTKEY, user, host, key, 0, NULL));
 }
 
 int
-mm_key_allowed(enum mm_keytype type, char *user, char *host, Key *key)
+mm_key_allowed(enum mm_keytype type, const char *user, const char *host,
+    struct sshkey *key, int pubkey_auth_attempt, struct sshauthopt **authoptp)
 {
-	Buffer m;
-	u_char *blob;
-	u_int len;
-	int allowed = 0, have_forced = 0;
+	struct sshbuf *m;
+	int r, allowed = 0;
+	struct sshauthopt *opts = NULL;
 
 	debug3("%s entering", __func__);
 
-	/* Convert the key to a blob and the pass it over */
-	if (!key_to_blob(key, &blob, &len))
-		return (0);
+	if (authoptp != NULL)
+		*authoptp = NULL;
 
-	buffer_init(&m);
-	buffer_put_int(&m, type);
-	buffer_put_cstring(&m, user ? user : "");
-	buffer_put_cstring(&m, host ? host : "");
-	buffer_put_string(&m, blob, len);
-	free(blob);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_u32(m, type)) != 0 ||
+	    (r = sshbuf_put_cstring(m, user ? user : "")) != 0 ||
+	    (r = sshbuf_put_cstring(m, host ? host : "")) != 0 ||
+	    (r = sshkey_puts(key, m)) != 0 ||
+	    (r = sshbuf_put_u32(m, pubkey_auth_attempt)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYALLOWED, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYALLOWED, m);
 
 	debug3("%s: waiting for MONITOR_ANS_KEYALLOWED", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_KEYALLOWED, &m);
-
-	allowed = buffer_get_int(&m);
-
-	/* fake forced command */
-	auth_clear_options();
-	have_forced = buffer_get_int(&m);
-	forced_command = have_forced ? xstrdup("true") : NULL;
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_KEYALLOWED, m);
+
+	if ((r = sshbuf_get_u32(m, &allowed)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (allowed && type == MM_USERKEY) {
+		if ((r = sshauthopt_deserialise(m, &opts)) != 0)
+			fatal("%s: sshauthopt_deserialise: %s",
+			    __func__, ssh_err(r));
+	}
+	sshbuf_free(m);
 
-	buffer_free(&m);
+	if (authoptp != NULL) {
+		*authoptp = opts;
+		opts = NULL;
+	}
+	sshauthopt_free(opts);
 
-	return (allowed);
+	return allowed;
 }
 
 /*
@@ -442,41 +492,58 @@ mm_key_allowed(enum mm_keytype type, char *user, char *host, Key *key)
  */
 
 int
-mm_key_verify(Key *key, u_char *sig, u_int siglen, u_char *data, u_int datalen)
+mm_sshkey_verify(const struct sshkey *key, const u_char *sig, size_t siglen,
+    const u_char *data, size_t datalen, const char *sigalg, u_int compat,
+    struct sshkey_sig_details **sig_detailsp)
 {
-	Buffer m;
-	u_char *blob;
-	u_int len;
-	int verified = 0;
+	struct sshbuf *m;
+	u_int encoded_ret = 0;
+	int r;
+	u_char sig_details_present, flags;
+	u_int counter;
 
 	debug3("%s entering", __func__);
 
-	/* Convert the key to a blob and the pass it over */
-	if (!key_to_blob(key, &blob, &len))
-		return (0);
-
-	buffer_init(&m);
-	buffer_put_string(&m, blob, len);
-	buffer_put_string(&m, sig, siglen);
-	buffer_put_string(&m, data, datalen);
-	free(blob);
+	if (sig_detailsp != NULL)
+		*sig_detailsp = NULL;
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshkey_puts(key, m)) != 0 ||
+	    (r = sshbuf_put_string(m, sig, siglen)) != 0 ||
+	    (r = sshbuf_put_string(m, data, datalen)) != 0 ||
+	    (r = sshbuf_put_cstring(m, sigalg == NULL ? "" : sigalg)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_KEYVERIFY, m);
 
 	debug3("%s: waiting for MONITOR_ANS_KEYVERIFY", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_KEYVERIFY, &m);
-
-	verified = buffer_get_int(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_KEYVERIFY, m);
+
+	if ((r = sshbuf_get_u32(m, &encoded_ret)) != 0 ||
+	    (r = sshbuf_get_u8(m, &sig_details_present)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (sig_details_present && encoded_ret == 0) {
+		if ((r = sshbuf_get_u32(m, &counter)) != 0 ||
+		    (r = sshbuf_get_u8(m, &flags)) != 0)
+			fatal("%s: buffer error: %s", __func__, ssh_err(r));
+		if (sig_detailsp != NULL) {
+			*sig_detailsp = xcalloc(1, sizeof(**sig_detailsp));
+			(*sig_detailsp)->sk_counter = counter;
+			(*sig_detailsp)->sk_flags = flags;
+		}
+	}
 
-	buffer_free(&m);
+	sshbuf_free(m);
 
-	return (verified);
+	if (encoded_ret != 0)
+		return SSH_ERR_SIGNATURE_INVALID;
+	return 0;
 }
 
 void
-mm_send_keystate(struct monitor *monitor)
+mm_send_keystate(struct ssh *ssh, struct monitor *monitor)
 {
-	struct ssh *ssh = active_state;		/* XXX */
 	struct sshbuf *m;
 	int r;
 
@@ -493,9 +560,9 @@ mm_send_keystate(struct monitor *monitor)
 int
 mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
 {
-	Buffer m;
+	struct sshbuf *m;
 	char *p, *msg;
-	int success = 0, tmp1 = -1, tmp2 = -1;
+	int success = 0, tmp1 = -1, tmp2 = -1, r;
 
 	/* Kludge: ensure there are fds free to receive the pty/tty */
 	if ((tmp1 = dup(pmonitor->m_recvfd)) == -1 ||
@@ -510,26 +577,30 @@ mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
 	close(tmp1);
 	close(tmp2);
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTY, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTY, m);
 
 	debug3("%s: waiting for MONITOR_ANS_PTY", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PTY, &m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PTY, m);
 
-	success = buffer_get_int(&m);
+	if ((r = sshbuf_get_u32(m, &success)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (success == 0) {
 		debug3("%s: pty alloc failed", __func__);
-		buffer_free(&m);
+		sshbuf_free(m);
 		return (0);
 	}
-	p = buffer_get_string(&m, NULL);
-	msg = buffer_get_string(&m, NULL);
-	buffer_free(&m);
+	if ((r = sshbuf_get_cstring(m, &p, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &msg, NULL)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 
 	strlcpy(namebuf, p, namebuflen); /* Possible truncation */
 	free(p);
 
-	buffer_append(&loginmsg, msg, strlen(msg));
+	if ((r = sshbuf_put(loginmsg, msg, strlen(msg))) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	free(msg);
 
 	if ((*ptyfd = mm_receive_fd(pmonitor->m_recvfd)) == -1 ||
@@ -543,17 +614,20 @@ mm_pty_allocate(int *ptyfd, int *ttyfd, char *namebuf, size_t namebuflen)
 void
 mm_session_pty_cleanup2(Session *s)
 {
-	Buffer m;
+	struct sshbuf *m;
+	int r;
 
 	if (s->ttyfd == -1)
 		return;
-	buffer_init(&m);
-	buffer_put_cstring(&m, s->tty);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTYCLEANUP, &m);
-	buffer_free(&m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, s->tty)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PTYCLEANUP, m);
+	sshbuf_free(m);
 
 	/* closed dup'ed master */
-	if (s->ptymaster != -1 && close(s->ptymaster) < 0)
+	if (s->ptymaster != -1 && close(s->ptymaster) == -1)
 		error("close(s->ptymaster/%d): %s",
 		    s->ptymaster, strerror(errno));
 
@@ -563,42 +637,46 @@ mm_session_pty_cleanup2(Session *s)
 
 #ifdef USE_PAM
 void
-mm_start_pam(Authctxt *authctxt)
+mm_start_pam(struct ssh *ssh)
 {
-	Buffer m;
+	struct sshbuf *m;
 
 	debug3("%s entering", __func__);
 	if (!options.use_pam)
 		fatal("UsePAM=no, but ended up in %s anyway", __func__);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_START, m);
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_START, &m);
-
-	buffer_free(&m);
+	sshbuf_free(m);
 }
 
 u_int
 mm_do_pam_account(void)
 {
-	Buffer m;
+	struct sshbuf *m;
 	u_int ret;
 	char *msg;
+	size_t msglen;
+	int r;
 
 	debug3("%s entering", __func__);
 	if (!options.use_pam)
 		fatal("UsePAM=no, but ended up in %s anyway", __func__);
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_ACCOUNT, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_ACCOUNT, m);
 
 	mm_request_receive_expect(pmonitor->m_recvfd,
-	    MONITOR_ANS_PAM_ACCOUNT, &m);
-	ret = buffer_get_int(&m);
-	msg = buffer_get_string(&m, NULL);
-	buffer_append(&loginmsg, msg, strlen(msg));
-	free(msg);
+	    MONITOR_ANS_PAM_ACCOUNT, m);
+	if ((r = sshbuf_get_u32(m, &ret)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &msg, &msglen)) != 0 ||
+	    (r = sshbuf_put(loginmsg, msg, msglen)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	buffer_free(&m);
+	free(msg);
+	sshbuf_free(m);
 
 	debug3("%s returning %d", __func__, ret);
 
@@ -608,22 +686,24 @@ mm_do_pam_account(void)
 void *
 mm_sshpam_init_ctx(Authctxt *authctxt)
 {
-	Buffer m;
-	int success;
+	struct sshbuf *m;
+	int r, success;
 
 	debug3("%s", __func__);
-	buffer_init(&m);
-	buffer_put_cstring(&m, authctxt->user);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_INIT_CTX, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_INIT_CTX, m);
 	debug3("%s: waiting for MONITOR_ANS_PAM_INIT_CTX", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_INIT_CTX, &m);
-	success = buffer_get_int(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_PAM_INIT_CTX, m);
+	if ((r = sshbuf_get_u32(m, &success)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (success == 0) {
 		debug3("%s: pam_init_ctx failed", __func__);
-		buffer_free(&m);
+		sshbuf_free(m);
 		return (NULL);
 	}
-	buffer_free(&m);
+	sshbuf_free(m);
 	return (authctxt);
 }
 
@@ -631,65 +711,79 @@ int
 mm_sshpam_query(void *ctx, char **name, char **info,
     u_int *num, char ***prompts, u_int **echo_on)
 {
-	Buffer m;
-	u_int i;
-	int ret;
+	struct sshbuf *m;
+	u_int i, n;
+	int r, ret;
 
 	debug3("%s", __func__);
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_QUERY, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_QUERY, m);
 	debug3("%s: waiting for MONITOR_ANS_PAM_QUERY", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_QUERY, &m);
-	ret = buffer_get_int(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_QUERY, m);
+	if ((r = sshbuf_get_u32(m, &ret)) != 0 ||
+	    (r = sshbuf_get_cstring(m, name, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, info, NULL)) != 0 ||
+	    (r = sshbuf_get_u32(m, &n)) != 0 ||
+	    (r = sshbuf_get_u32(m, num)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	debug3("%s: pam_query returned %d", __func__, ret);
-	*name = buffer_get_string(&m, NULL);
-	*info = buffer_get_string(&m, NULL);
-	*num = buffer_get_int(&m);
+	sshpam_set_maxtries_reached(n);
 	if (*num > PAM_MAX_NUM_MSG)
-		fatal("%s: recieved %u PAM messages, expected <= %u",
+		fatal("%s: received %u PAM messages, expected <= %u",
 		    __func__, *num, PAM_MAX_NUM_MSG);
 	*prompts = xcalloc((*num + 1), sizeof(char *));
 	*echo_on = xcalloc((*num + 1), sizeof(u_int));
 	for (i = 0; i < *num; ++i) {
-		(*prompts)[i] = buffer_get_string(&m, NULL);
-		(*echo_on)[i] = buffer_get_int(&m);
+		if ((r = sshbuf_get_cstring(m, &((*prompts)[i]), NULL)) != 0 ||
+		    (r = sshbuf_get_u32(m, &((*echo_on)[i]))) != 0)
+			fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	}
-	buffer_free(&m);
+	sshbuf_free(m);
 	return (ret);
 }
 
 int
 mm_sshpam_respond(void *ctx, u_int num, char **resp)
 {
-	Buffer m;
-	u_int i;
-	int ret;
+	struct sshbuf *m;
+	u_int n, i;
+	int r, ret;
 
 	debug3("%s", __func__);
-	buffer_init(&m);
-	buffer_put_int(&m, num);
-	for (i = 0; i < num; ++i)
-		buffer_put_cstring(&m, resp[i]);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_RESPOND, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_u32(m, num)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	for (i = 0; i < num; ++i) {
+		if ((r = sshbuf_put_cstring(m, resp[i])) != 0)
+			fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	}
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_RESPOND, m);
 	debug3("%s: waiting for MONITOR_ANS_PAM_RESPOND", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_RESPOND, &m);
-	ret = buffer_get_int(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_PAM_RESPOND, m);
+	if ((r = sshbuf_get_u32(m, &n)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	ret = (int)n; /* XXX */
 	debug3("%s: pam_respond returned %d", __func__, ret);
-	buffer_free(&m);
+	sshbuf_free(m);
 	return (ret);
 }
 
 void
 mm_sshpam_free_ctx(void *ctxtp)
 {
-	Buffer m;
+	struct sshbuf *m;
 
 	debug3("%s", __func__);
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_FREE_CTX, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_FREE_CTX, m);
 	debug3("%s: waiting for MONITOR_ANS_PAM_FREE_CTX", __func__);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_FREE_CTX, &m);
-	buffer_free(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_PAM_FREE_CTX, m);
+	sshbuf_free(m);
 }
 #endif /* USE_PAM */
 
@@ -698,35 +792,14 @@ mm_sshpam_free_ctx(void *ctxtp)
 void
 mm_terminate(void)
 {
-	Buffer m;
+	struct sshbuf *m;
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_TERM, &m);
-	buffer_free(&m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_TERM, m);
+	sshbuf_free(m);
 }
 
-#ifdef WITH_SSH1
-int
-mm_ssh1_session_key(BIGNUM *num)
-{
-	int rsafail;
-	Buffer m;
-
-	buffer_init(&m);
-	buffer_put_bignum2(&m, num);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SESSKEY, &m);
-
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SESSKEY, &m);
-
-	rsafail = buffer_get_int(&m);
-	buffer_get_bignum2(&m, num);
-
-	buffer_free(&m);
-
-	return (rsafail);
-}
-#endif
-
 static void
 mm_chall_setup(char **name, char **infotxt, u_int *numprompts,
     char ***prompts, u_int **echo_on)
@@ -743,27 +816,31 @@ int
 mm_bsdauth_query(void *ctx, char **name, char **infotxt,
    u_int *numprompts, char ***prompts, u_int **echo_on)
 {
-	Buffer m;
+	struct sshbuf *m;
 	u_int success;
 	char *challenge;
+	int r;
 
 	debug3("%s: entering", __func__);
 
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHQUERY, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHQUERY, m);
 
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_BSDAUTHQUERY,
-	    &m);
-	success = buffer_get_int(&m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_BSDAUTHQUERY, m);
+	if ((r = sshbuf_get_u32(m, &success)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 	if (success == 0) {
 		debug3("%s: no challenge", __func__);
-		buffer_free(&m);
+		sshbuf_free(m);
 		return (-1);
 	}
 
 	/* Get the challenge, and format the response */
-	challenge  = buffer_get_string(&m, NULL);
-	buffer_free(&m);
+	if ((r = sshbuf_get_cstring(m, &challenge, NULL)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 
 	mm_chall_setup(name, infotxt, numprompts, prompts, echo_on);
 	(*prompts)[0] = challenge;
@@ -776,228 +853,62 @@ mm_bsdauth_query(void *ctx, char **name, char **infotxt,
 int
 mm_bsdauth_respond(void *ctx, u_int numresponses, char **responses)
 {
-	Buffer m;
-	int authok;
-
-	debug3("%s: entering", __func__);
-	if (numresponses != 1)
-		return (-1);
-
-	buffer_init(&m);
-	buffer_put_cstring(&m, responses[0]);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHRESPOND, &m);
-
-	mm_request_receive_expect(pmonitor->m_recvfd,
-	    MONITOR_ANS_BSDAUTHRESPOND, &m);
-
-	authok = buffer_get_int(&m);
-	buffer_free(&m);
-
-	return ((authok == 0) ? -1 : 0);
-}
-
-#ifdef SKEY
-int
-mm_skey_query(void *ctx, char **name, char **infotxt,
-   u_int *numprompts, char ***prompts, u_int **echo_on)
-{
-	Buffer m;
-	u_int success;
-	char *challenge;
-
-	debug3("%s: entering", __func__);
-
-	buffer_init(&m);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SKEYQUERY, &m);
-
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_SKEYQUERY,
-	    &m);
-	success = buffer_get_int(&m);
-	if (success == 0) {
-		debug3("%s: no challenge", __func__);
-		buffer_free(&m);
-		return (-1);
-	}
-
-	/* Get the challenge, and format the response */
-	challenge  = buffer_get_string(&m, NULL);
-	buffer_free(&m);
-
-	debug3("%s: received challenge: %s", __func__, challenge);
-
-	mm_chall_setup(name, infotxt, numprompts, prompts, echo_on);
-
-	xasprintf(*prompts, "%s%s", challenge, SKEY_PROMPT);
-	free(challenge);
-
-	return (0);
-}
-
-int
-mm_skey_respond(void *ctx, u_int numresponses, char **responses)
-{
-	Buffer m;
-	int authok;
+	struct sshbuf *m;
+	int r, authok;
 
 	debug3("%s: entering", __func__);
 	if (numresponses != 1)
 		return (-1);
 
-	buffer_init(&m);
-	buffer_put_cstring(&m, responses[0]);
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SKEYRESPOND, &m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, responses[0])) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_BSDAUTHRESPOND, m);
 
 	mm_request_receive_expect(pmonitor->m_recvfd,
-	    MONITOR_ANS_SKEYRESPOND, &m);
+	    MONITOR_ANS_BSDAUTHRESPOND, m);
 
-	authok = buffer_get_int(&m);
-	buffer_free(&m);
+	if ((r = sshbuf_get_u32(m, &authok)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 
 	return ((authok == 0) ? -1 : 0);
 }
-#endif /* SKEY */
-
-void
-mm_ssh1_session_id(u_char session_id[16])
-{
-	Buffer m;
-	int i;
-
-	debug3("%s entering", __func__);
-
-	buffer_init(&m);
-	for (i = 0; i < 16; i++)
-		buffer_put_char(&m, session_id[i]);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_SESSID, &m);
-	buffer_free(&m);
-}
-
-#ifdef WITH_SSH1
-int
-mm_auth_rsa_key_allowed(struct passwd *pw, BIGNUM *client_n, Key **rkey)
-{
-	Buffer m;
-	Key *key;
-	u_char *blob;
-	u_int blen;
-	int allowed = 0, have_forced = 0;
-
-	debug3("%s entering", __func__);
-
-	buffer_init(&m);
-	buffer_put_bignum2(&m, client_n);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSAKEYALLOWED, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSAKEYALLOWED, &m);
-
-	allowed = buffer_get_int(&m);
-
-	/* fake forced command */
-	auth_clear_options();
-	have_forced = buffer_get_int(&m);
-	forced_command = have_forced ? xstrdup("true") : NULL;
-
-	if (allowed && rkey != NULL) {
-		blob = buffer_get_string(&m, &blen);
-		if ((key = key_from_blob(blob, blen)) == NULL)
-			fatal("%s: key_from_blob failed", __func__);
-		*rkey = key;
-		free(blob);
-	}
-	buffer_free(&m);
-
-	return (allowed);
-}
-
-BIGNUM *
-mm_auth_rsa_generate_challenge(Key *key)
-{
-	Buffer m;
-	BIGNUM *challenge;
-	u_char *blob;
-	u_int blen;
-
-	debug3("%s entering", __func__);
-
-	if ((challenge = BN_new()) == NULL)
-		fatal("%s: BN_new failed", __func__);
-
-	key->type = KEY_RSA;    /* XXX cheat for key_to_blob */
-	if (key_to_blob(key, &blob, &blen) == 0)
-		fatal("%s: key_to_blob failed", __func__);
-	key->type = KEY_RSA1;
-
-	buffer_init(&m);
-	buffer_put_string(&m, blob, blen);
-	free(blob);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSACHALLENGE, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSACHALLENGE, &m);
-
-	buffer_get_bignum2(&m, challenge);
-	buffer_free(&m);
-
-	return (challenge);
-}
-
-int
-mm_auth_rsa_verify_response(Key *key, BIGNUM *p, u_char response[16])
-{
-	Buffer m;
-	u_char *blob;
-	u_int blen;
-	int success = 0;
-
-	debug3("%s entering", __func__);
-
-	key->type = KEY_RSA;    /* XXX cheat for key_to_blob */
-	if (key_to_blob(key, &blob, &blen) == 0)
-		fatal("%s: key_to_blob failed", __func__);
-	key->type = KEY_RSA1;
-
-	buffer_init(&m);
-	buffer_put_string(&m, blob, blen);
-	buffer_put_string(&m, response, 16);
-	free(blob);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_RSARESPONSE, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_RSARESPONSE, &m);
-
-	success = buffer_get_int(&m);
-	buffer_free(&m);
-
-	return (success);
-}
-#endif
 
 #ifdef SSH_AUDIT_EVENTS
 void
-mm_audit_event(ssh_audit_event_t event)
+mm_audit_event(struct ssh *ssh, ssh_audit_event_t event)
 {
-	Buffer m;
+	struct sshbuf *m;
+	int r;
 
 	debug3("%s entering", __func__);
 
-	buffer_init(&m);
-	buffer_put_int(&m, event);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_u32(m, event)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_EVENT, &m);
-	buffer_free(&m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_EVENT, m);
+	sshbuf_free(m);
 }
 
 void
 mm_audit_run_command(const char *command)
 {
-	Buffer m;
+	struct sshbuf *m;
+	int r;
 
 	debug3("%s entering command %s", __func__, command);
 
-	buffer_init(&m);
-	buffer_put_cstring(&m, command);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_cstring(m, command)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_COMMAND, &m);
-	buffer_free(&m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_AUDIT_COMMAND, m);
+	sshbuf_free(m);
 }
 #endif /* SSH_AUDIT_EVENTS */
 
@@ -1005,45 +916,55 @@ mm_audit_run_command(const char *command)
 OM_uint32
 mm_ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID goid)
 {
-	Buffer m;
+	struct sshbuf *m;
 	OM_uint32 major;
+	int r;
 
 	/* Client doesn't get to see the context */
 	*ctx = NULL;
 
-	buffer_init(&m);
-	buffer_put_string(&m, goid->elements, goid->length);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_string(m, goid->elements, goid->length)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSETUP, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSETUP, &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSETUP, m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSETUP, m);
 
-	major = buffer_get_int(&m);
+	if ((r = sshbuf_get_u32(m, &major)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	buffer_free(&m);
+	sshbuf_free(m);
 	return (major);
 }
 
 OM_uint32
 mm_ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *in,
-    gss_buffer_desc *out, OM_uint32 *flags)
+    gss_buffer_desc *out, OM_uint32 *flagsp)
 {
-	Buffer m;
+	struct sshbuf *m;
 	OM_uint32 major;
-	u_int len;
-
-	buffer_init(&m);
-	buffer_put_string(&m, in->value, in->length);
-
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSTEP, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSTEP, &m);
+	u_int flags;
+	int r;
 
-	major = buffer_get_int(&m);
-	out->value = buffer_get_string(&m, &len);
-	out->length = len;
-	if (flags)
-		*flags = buffer_get_int(&m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_string(m, in->value, in->length)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSTEP, m);
+	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSTEP, m);
+
+	if ((r = sshbuf_get_u32(m, &major)) != 0 ||
+	    (r = ssh_gssapi_get_buffer_desc(m, out)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	if (flagsp != NULL) {
+		if ((r = sshbuf_get_u32(m, &flags)) != 0)
+			fatal("%s: buffer error: %s", __func__, ssh_err(r));
+		*flagsp = flags;
+	}
 
-	buffer_free(&m);
+	sshbuf_free(m);
 
 	return (major);
 }
@@ -1051,39 +972,44 @@ mm_ssh_gssapi_accept_ctx(Gssctxt *ctx, gss_buffer_desc *in,
 OM_uint32
 mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
 {
-	Buffer m;
+	struct sshbuf *m;
 	OM_uint32 major;
+	int r;
 
-	buffer_init(&m);
-	buffer_put_string(&m, gssbuf->value, gssbuf->length);
-	buffer_put_string(&m, gssmic->value, gssmic->length);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
+	if ((r = sshbuf_put_string(m, gssbuf->value, gssbuf->length)) != 0 ||
+	    (r = sshbuf_put_string(m, gssmic->value, gssmic->length)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSCHECKMIC, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSCHECKMIC,
-	    &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSCHECKMIC, m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_GSSCHECKMIC, m);
 
-	major = buffer_get_int(&m);
-	buffer_free(&m);
+	if ((r = sshbuf_get_u32(m, &major)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
+	sshbuf_free(m);
 	return(major);
 }
 
 int
 mm_ssh_gssapi_userok(char *user)
 {
-	Buffer m;
-	int authenticated = 0;
+	struct sshbuf *m;
+	int r, authenticated = 0;
 
-	buffer_init(&m);
+	if ((m = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
 
-	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, &m);
-	mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUSEROK,
-				  &m);
+	mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, m);
+	mm_request_receive_expect(pmonitor->m_recvfd,
+	    MONITOR_ANS_GSSUSEROK, m);
 
-	authenticated = buffer_get_int(&m);
+	if ((r = sshbuf_get_u32(m, &authenticated)) != 0)
+		fatal("%s: buffer error: %s", __func__, ssh_err(r));
 
-	buffer_free(&m);
+	sshbuf_free(m);
 	debug3("%s: user %sauthenticated",__func__, authenticated ? "" : "not ");
 	return (authenticated);
 }
 #endif /* GSSAPI */
-