diff -up openssh-7.4p1/configure.ac.vendor openssh-7.4p1/configure.ac

--- openssh-7.4p1/configure.ac.vendor	2017-02-10 10:45:54.977836854 +0100

+++ openssh-7.4p1/configure.ac	2017-02-10 10:45:54.995836725 +0100

@@ -4930,6 +4930,12 @@ AC_ARG_WITH([lastlog],

 		fi

 	]

 )

+AC_ARG_ENABLE(vendor-patchlevel,

+  [  --enable-vendor-patchlevel=TAG  specify a vendor patch level],

+  [AC_DEFINE_UNQUOTED(SSH_VENDOR_PATCHLEVEL,[SSH_RELEASE "-" "$enableval"],[Define to your vendor patch level, if it has been modified from the upstream source release.])

+   SSH_VENDOR_PATCHLEVEL="$enableval"],

+  [AC_DEFINE(SSH_VENDOR_PATCHLEVEL,SSH_RELEASE,[Define to your vendor patch level, if it has been modified from the upstream source release.])

+   SSH_VENDOR_PATCHLEVEL=none])

 dnl lastlog, [uw]tmpx? detection

 dnl  NOTE: set the paths in the platform section to avoid the

@@ -5194,6 +5200,7 @@ echo "           Translate v4 in v6 hack

 echo "                  BSD Auth support: $BSD_AUTH_MSG"

 echo "              Random number source: $RAND_MSG"

 echo "             Privsep sandbox style: $SANDBOX_STYLE"

+echo "                Vendor patch level: $SSH_VENDOR_PATCHLEVEL"

 echo ""

diff -up openssh-7.4p1/servconf.c.vendor openssh-7.4p1/servconf.c

--- openssh-7.4p1/servconf.c.vendor	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/servconf.c	2017-02-10 10:45:54.995836725 +0100

@@ -143,6 +143,7 @@ initialize_server_options(ServerOptions

 	options->max_authtries = -1;

 	options->max_sessions = -1;

 	options->banner = NULL;

+	options->show_patchlevel = -1;

 	options->use_dns = -1;

 	options->client_alive_interval = -1;

 	options->client_alive_count_max = -1;

@@ -325,6 +326,8 @@ fill_default_server_options(ServerOption

 		options->ip_qos_bulk = IPTOS_THROUGHPUT;

 	if (options->version_addendum == NULL)

 		options->version_addendum = xstrdup("");

+	if (options->show_patchlevel == -1)

+		options->show_patchlevel = 0;

 	if (options->fwd_opts.streamlocal_bind_mask == (mode_t)-1)

 		options->fwd_opts.streamlocal_bind_mask = 0177;

 	if (options->fwd_opts.streamlocal_bind_unlink == -1)

@@ -402,7 +405,7 @@ typedef enum {

 	sIgnoreUserKnownHosts, sCiphers, sMacs, sPidFile,

 	sGatewayPorts, sPubkeyAuthentication, sPubkeyAcceptedKeyTypes,

 	sXAuthLocation, sSubsystem, sMaxStartups, sMaxAuthTries, sMaxSessions,

-	sBanner, sUseDNS, sHostbasedAuthentication,

+	sBanner, sShowPatchLevel, sUseDNS, sHostbasedAuthentication,

 	sHostbasedUsesNameFromPacketOnly, sHostbasedAcceptedKeyTypes,

 	sHostKeyAlgorithms,

 	sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,

@@ -528,6 +531,7 @@ static struct {

 	{ "maxauthtries", sMaxAuthTries, SSHCFG_ALL },

 	{ "maxsessions", sMaxSessions, SSHCFG_ALL },

 	{ "banner", sBanner, SSHCFG_ALL },

+	{ "showpatchlevel", sShowPatchLevel, SSHCFG_GLOBAL },

 	{ "usedns", sUseDNS, SSHCFG_GLOBAL },

 	{ "verifyreversemapping", sDeprecated, SSHCFG_GLOBAL },

 	{ "reversemappingcheck", sDeprecated, SSHCFG_GLOBAL },

@@ -1369,6 +1373,10 @@ process_server_config_line(ServerOptions

 		multistate_ptr = multistate_privsep;

 		goto parse_multistate;

+	case sShowPatchLevel:

+		intptr = &options->show_patchlevel;

+		goto parse_flag;

+

 	case sAllowUsers:

 		while ((arg = strdelim(&cp)) && *arg != '\0') {

 			if (options->num_allow_users >= MAX_ALLOW_USERS)

@@ -2269,6 +2277,7 @@ dump_config(ServerOptions *o)

 	dump_cfg_fmtint(sPermitUserEnvironment, o->permit_user_env);

 	dump_cfg_fmtint(sCompression, o->compression);

 	dump_cfg_fmtint(sGatewayPorts, o->fwd_opts.gateway_ports);

+	dump_cfg_fmtint(sShowPatchLevel, o->show_patchlevel);

 	dump_cfg_fmtint(sUseDNS, o->use_dns);

 	dump_cfg_fmtint(sAllowTcpForwarding, o->allow_tcp_forwarding);

 	dump_cfg_fmtint(sAllowAgentForwarding, o->allow_agent_forwarding);

diff -up openssh-7.4p1/servconf.h.vendor openssh-7.4p1/servconf.h

--- openssh-7.4p1/servconf.h.vendor	2016-12-19 05:59:41.000000000 +0100

+++ openssh-7.4p1/servconf.h	2017-02-10 10:45:54.995836725 +0100

@@ -149,6 +149,7 @@ typedef struct {

 	int	max_authtries;

 	int	max_sessions;

 	char   *banner;			/* SSH-2 banner message */

+	int	show_patchlevel;	/* Show vendor patch level to clients */

 	int	use_dns;

 	int	client_alive_interval;	/*

 					 * poke the client this often to

diff -up openssh-7.4p1/sshd_config.5.vendor openssh-7.4p1/sshd_config.5

--- openssh-7.4p1/sshd_config.5.vendor	2017-02-10 10:45:54.990836761 +0100

+++ openssh-7.4p1/sshd_config.5	2017-02-10 10:45:54.996836718 +0100

@@ -1334,6 +1334,14 @@ an OpenSSH Key Revocation List (KRL) as

 .Xr ssh-keygen 1 .

 For more information on KRLs, see the KEY REVOCATION LISTS section in

 .Xr ssh-keygen 1 .

+.It Cm ShowPatchLevel 

+Specifies whether 

+.Nm sshd 

+will display the patch level of the binary in the identification string. 

+The patch level is set at compile-time. 

+The default is 

+.Dq no . 

+This option applies to protocol version 1 only. 

 .It Cm StreamLocalBindMask

 Sets the octal file creation mode mask

 .Pq umask

diff -up openssh-7.4p1/sshd_config.vendor openssh-7.4p1/sshd_config

--- openssh-7.4p1/sshd_config.vendor	2017-02-10 10:45:54.990836761 +0100

+++ openssh-7.4p1/sshd_config	2017-02-10 10:45:54.996836718 +0100

@@ -105,6 +105,7 @@ X11Forwarding yes

 #Compression delayed

 #ClientAliveInterval 0

 #ClientAliveCountMax 3

+#ShowPatchLevel no

 #UseDNS no

 #PidFile /var/run/sshd.pid

 #MaxStartups 10:30:100

diff -up openssh-7.4p1/sshd.c.vendor openssh-7.4p1/sshd.c

--- openssh-7.4p1/sshd.c.vendor	2017-02-10 10:45:54.996836718 +0100

+++ openssh-7.4p1/sshd.c	2017-02-10 10:48:41.633648667 +0100

@@ -367,7 +367,8 @@ sshd_exchange_identification(struct ssh

 	char remote_version[256];	/* Must be at least as big as buf. */

 	xasprintf(&server_version_string, "SSH-%d.%d-%.100s%s%s%s",

-	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION,

+	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2,

+	    (options.show_patchlevel == 1) ? SSH_VENDOR_PATCHLEVEL : SSH_VERSION,

 	    *options.version_addendum == '\0' ? "" : " ",

 	    options.version_addendum, newline);

@@ -1654,7 +1655,8 @@ main(int ac, char **av)

 		exit(1);

 	}

-	debug("sshd version %s, %s", SSH_VERSION,

+	debug("sshd version %s, %s",

+	    (options.show_patchlevel == 1) ? SSH_VENDOR_PATCHLEVEL : SSH_VERSION,

 #ifdef WITH_OPENSSL

 	    SSLeay_version(SSLEAY_VERSION)

 #else