Add refactored blacklist support to sshd

Change the calls to of blacklist_init() and blacklist_notify to be
macros defined in the blacklist_client.h file.  This avoids
the need for #ifdef USE_BLACKLIST / #endif except in the
blacklist.c file.

Remove redundent initialization attempts from within
blacklist_notify - everything always goes through
blacklistd_init().

Added UseBlacklist option to sshd, which defaults to off.
To enable the functionality, use '-o UseBlacklist=yes' on
the command line, or uncomment in the sshd_config file.

Reviewed by:	des
Approved by:	des
MFC after:		1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D7051

crypto/openssh/auth-pam.c

@@ -98,6 +98,7 @@
 #include "ssh-gss.h"
 #endif
 #include "monitor_wrap.h"
+#include "blacklist_client.h"
 
 extern ServerOptions options;
 extern Buffer loginmsg;
@@ -794,6 +795,7 @@ sshpam_query(void *ctx, char **name, char **info,
 				free(msg);
 				return (0);
 			}
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 			error("PAM: %s for %s%.100s from %.100s", msg,
 			    sshpam_authctxt->valid ? "" : "illegal user ",
 			    sshpam_authctxt->user,

crypto/openssh/auth.c

@@ -75,6 +75,7 @@ __RCSID("$FreeBSD$");
 #include "authfile.h"
 #include "ssherr.h"
 #include "compat.h"
+#include "blacklist_client.h"
 
 /* import */
 extern ServerOptions options;
@@ -292,8 +293,11 @@ auth_log(Authctxt *authctxt, int authenticated, int partial,
 		authmsg = "Postponed";
 	else if (partial)
 		authmsg = "Partial";
-	else
+	else {
 		authmsg = authenticated ? "Accepted" : "Failed";
+		BLACKLIST_NOTIFY(authenticated ?
+		    BLACKLIST_AUTH_OK : BLACKLIST_AUTH_FAIL);
+	}
 
 	authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
 	    authmsg,
@@ -640,6 +644,7 @@ getpwnamallow(const char *user)
 	}
 #endif
 	if (pw == NULL) {
+		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 		logit("Invalid user %.100s from %.100s",
 		    user, get_remote_ipaddr());
 #ifdef CUSTOM_FAILED_LOGIN

crypto/openssh/auth1.c

@@ -43,6 +43,7 @@
 #endif
 #include "monitor_wrap.h"
 #include "buffer.h"
+#include "blacklist_client.h"
 
 /* import */
 extern ServerOptions options;
@@ -337,6 +338,7 @@ do_authloop(Authctxt *authctxt)
 			char *msg;
 			size_t len;
 
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 			error("Access denied for user %s by PAM account "
 			    "configuration", authctxt->user);
 			len = buffer_len(&loginmsg);
@@ -404,6 +406,7 @@ do_authentication(Authctxt *authctxt)
 	else {
 		debug("do_authentication: invalid user %s", user);
 		authctxt->pw = fakepw();
+		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 	}
 
 	/* Configuration may have changed as a result of Match */

crypto/openssh/auth2.c

@@ -52,6 +52,7 @@ __RCSID("$FreeBSD$");
 #include "pathnames.h"
 #include "buffer.h"
 #include "canohost.h"
+#include "blacklist_client.h"
 
 #ifdef GSSAPI
 #include "ssh-gss.h"
@@ -248,6 +249,7 @@ input_userauth_request(int type, u_int32_t seq, void *ctxt)
 		} else {
 			logit("input_userauth_request: invalid user %s", user);
 			authctxt->pw = fakepw();
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 #ifdef SSH_AUDIT_EVENTS
 			PRIVSEP(audit_event(SSH_INVALID_USER));
 #endif

crypto/openssh/blacklist.c

@@ -0,0 +1,97 @@
+/*-
+ * Copyright (c) 2015 The NetBSD Foundation, Inc.
+ * Copyright (c) 2016 The FreeBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Portions of this software were developed by Kurt Lidl
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <syslog.h>
+#include <unistd.h>
+
+#include "ssh.h"
+#include "packet.h"
+#include "log.h"
+#include "misc.h"
+#include "servconf.h"
+#include "blacklist_client.h"
+#include <blacklist.h>
+
+static struct blacklist *blstate = NULL;
+
+/* import */
+extern ServerOptions options;
+
+/* internal definition from bl.h */
+struct blacklist *bl_create(bool, char *, void (*)(int, const char *, va_list));
+
+/* impedence match vsyslog() to sshd's internal logging levels */
+void
+im_log(int priority, const char *message, va_list args)
+{
+	LogLevel imlevel;
+
+	switch (priority) {
+	case LOG_ERR:
+		imlevel = SYSLOG_LEVEL_ERROR;
+		break;
+	case LOG_DEBUG:
+		imlevel = SYSLOG_LEVEL_DEBUG1;
+		break;
+	case LOG_INFO:
+		imlevel = SYSLOG_LEVEL_INFO;
+		break;
+	default:
+		imlevel = SYSLOG_LEVEL_DEBUG2;
+	}
+	do_log(imlevel, message, args);
+}
+
+void
+blacklist_init(void)
+{
+
+	if (options.use_blacklist)
+		blstate = bl_create(false, NULL, im_log);
+}
+
+void
+blacklist_notify(int action)
+{
+
+	if (blstate != NULL && packet_connection_is_on_socket())
+		(void)blacklist_r(blstate, action,
+		packet_get_connection_in(), "ssh");
+}

crypto/openssh/blacklist_client.h

@@ -0,0 +1,57 @@
+/*-
+ * Copyright (c) 2015 The NetBSD Foundation, Inc.
+ * Copyright (c) 2016 The FreeBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Portions of this software were developed by Kurt Lidl
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef BLACKLIST_CLIENT_H
+#define BLACKLIST_CLIENT_H
+
+enum {
+	BLACKLIST_AUTH_OK = 0,
+	BLACKLIST_AUTH_FAIL
+};
+
+#ifdef USE_BLACKLIST
+void blacklist_init(void);
+void blacklist_notify(int);
+
+#define BLACKLIST_INIT() blacklist_init()
+#define BLACKLIST_NOTIFY(x) blacklist_notify(x)
+
+#else
+
+#define BLACKLIST_INIT()
+#define BLACKLIST_NOTIFY(x)
+
+#endif
+
+
+#endif /* BLACKLIST_CLIENT_H */

crypto/openssh/packet.c

@@ -86,6 +86,7 @@ __RCSID("$FreeBSD$");
 #include "packet.h"
 #include "ssherr.h"
 #include "sshbuf.h"
+#include "blacklist_client.h"
 
 #ifdef PACKET_DEBUG
 #define DBG(x) x
@@ -2071,6 +2072,7 @@ sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
 	case SSH_ERR_NO_KEX_ALG_MATCH:
 	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
 		if (ssh && ssh->kex && ssh->kex->failed_choice) {
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
 			fatal("Unable to negotiate with %.200s port %d: %s. "
 			    "Their offer: %s", ssh_remote_ipaddr(ssh),
 			    ssh_remote_port(ssh), ssh_err(r),

crypto/openssh/servconf.c

@@ -172,6 +172,7 @@ initialize_server_options(ServerOptions *options)
 	options->ip_qos_bulk = -1;
 	options->version_addendum = NULL;
 	options->fingerprint_hash = -1;
+	options->use_blacklist = -1;
 }
 
 /* Returns 1 if a string option is unset or set to "none" or 0 otherwise. */
@@ -360,6 +361,8 @@ fill_default_server_options(ServerOptions *options)
 		options->fwd_opts.streamlocal_bind_unlink = 0;
 	if (options->fingerprint_hash == -1)
 		options->fingerprint_hash = SSH_FP_HASH_DEFAULT;
+	if (options->use_blacklist == -1)
+		options->use_blacklist = 0;
 
 	assemble_algorithms(options);
 
@@ -437,6 +440,7 @@ typedef enum {
 	sAuthenticationMethods, sHostKeyAgent, sPermitUserRC,
 	sStreamLocalBindMask, sStreamLocalBindUnlink,
 	sAllowStreamLocalForwarding, sFingerprintHash,
+	sUseBlacklist,
 	sDeprecated, sUnsupported
 } ServerOpCodes;
 
@@ -579,6 +583,7 @@ static struct {
 	{ "streamlocalbindunlink", sStreamLocalBindUnlink, SSHCFG_ALL },
 	{ "allowstreamlocalforwarding", sAllowStreamLocalForwarding, SSHCFG_ALL },
 	{ "fingerprinthash", sFingerprintHash, SSHCFG_GLOBAL },
+	{ "useblacklist", sUseBlacklist, SSHCFG_GLOBAL },
 	{ "noneenabled", sUnsupported, SSHCFG_ALL },
 	{ "hpndisabled", sDeprecated, SSHCFG_ALL },
 	{ "hpnbuffersize", sDeprecated, SSHCFG_ALL },
@@ -1861,6 +1866,10 @@ process_server_config_line(ServerOptions *options, char *line,
 			options->fingerprint_hash = value;
 		break;
 
+	case sUseBlacklist:
+		intptr = &options->use_blacklist;
+		goto parse_flag;
+
 	case sDeprecated:
 		logit("%s line %d: Deprecated option %s",
 		    filename, linenum, arg);
@@ -2304,6 +2313,7 @@ dump_config(ServerOptions *o)
 	dump_cfg_fmtint(sAllowStreamLocalForwarding, o->allow_streamlocal_forwarding);
 	dump_cfg_fmtint(sUsePrivilegeSeparation, use_privsep);
 	dump_cfg_fmtint(sFingerprintHash, o->fingerprint_hash);
+	dump_cfg_fmtint(sUseBlacklist, o->use_blacklist);
 
 	/* string arguments */
 	dump_cfg_string(sPidFile, o->pid_file);

crypto/openssh/servconf.h

@@ -195,6 +195,7 @@ typedef struct {
 	char   *auth_methods[MAX_AUTH_METHODS];
 
 	int	fingerprint_hash;
+	int	use_blacklist;
 }       ServerOptions;
 
 /* Information about the incoming connection as used by Match */

crypto/openssh/sshd.c

@@ -135,6 +135,7 @@ __RCSID("$FreeBSD$");
 #include "ssh-sandbox.h"
 #include "version.h"
 #include "ssherr.h"
+#include "blacklist_client.h"
 
 #ifdef LIBWRAP
 #include <tcpd.h>
@@ -388,6 +389,8 @@ grace_alarm_handler(int sig)
 		kill(0, SIGTERM);
 	}
 
+	BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+
 	/* Log error and exit. */
 	sigdie("Timeout before authentication for %s", get_remote_ipaddr());
 }
@@ -2251,6 +2254,8 @@ main(int ac, char **av)
 	buffer_init(&loginmsg);
 	auth_debug_reset();
 
+	BLACKLIST_INIT();
+
 	if (use_privsep) {
 		if (privsep_preauth(authctxt) == 1)
 			goto authenticated;

crypto/openssh/sshd_config

@@ -120,6 +120,7 @@
 #MaxStartups 10:30:100
 #PermitTunnel no
 #ChrootDirectory none
+#UseBlacklist no
 #VersionAddendum FreeBSD-20160310
 
 # no default banner path

crypto/openssh/sshd_config.5

@@ -1537,6 +1537,15 @@ for authentication using
 .Cm TrustedUserCAKeys .
 For more details on certificates, see the CERTIFICATES section in
 .Xr ssh-keygen 1 .
+.It Cm UseBlacklist
+Specifies whether
+.Xr sshd 8
+attempts to send authentication success and failure messages
+to the
+.Xr blacklistd 8
+daemon.
+The default is
+.Dq no .
 .It Cm UseDNS
 Specifies whether
 .Xr sshd 8

secure/usr.sbin/sshd/Makefile

@@ -40,6 +40,13 @@ CFLAGS+= -DUSE_BSM_AUDIT -DHAVE_GETAUDIT_ADDR
 LIBADD+=	bsm
 .endif
 
+.if ${MK_BLACKLIST_SUPPORT} != "no"
+CFLAGS+= -DUSE_BLACKLIST -I${SRCTOP}/contrib/blacklist/include
+SRCS+=	blacklist.c
+LIBADD+= blacklist
+LDFLAGS+=-L${LIBBLACKLISTDIR}
+.endif
+
 .if ${MK_KERBEROS_SUPPORT} != "no"
 CFLAGS+= -include krb5_config.h
 SRCS+=	krb5_config.h

secure/usr.sbin/sshd/Makefile.depend

@@ -17,6 +17,7 @@ DIRDEPS = \
 	kerberos5/lib/libroken \
 	kerberos5/lib/libwind \
 	lib/${CSU_DIR} \
+	lib/libblacklist \
 	lib/libbsm \
 	lib/libc \
 	lib/libcom_err \