Refine and update blacklist support in sshd

Adjust notification points slightly to catch all auth failures,
rather than just the ones caused by bad usernames.

Modify notification point for bad usernames to send new type of
BLACKLIST_BAD_USER. (Support in libblacklist will be forthcoming soon.)
Add guards to allow library headers to expose the enum of action values.

Reviewed by:	des
Approved by:	des
Sponsored by:	The FreeBSD Foundation

crypto/openssh/auth-pam.c

@@ -799,7 +799,8 @@ sshpam_query(void *ctx, char **name, char **info,
 				free(msg);
 				return (0);
 			}
-			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+			BLACKLIST_NOTIFY(BLACKLIST_BAD_USER,
+			    sshpam_authctxt->user);
 			error("PAM: %s for %s%.100s from %.100s", msg,
 			    sshpam_authctxt->valid ? "" : "illegal user ",
 			    sshpam_authctxt->user,

crypto/openssh/auth.c

@@ -311,7 +311,7 @@ auth_log(Authctxt *authctxt, int authenticated, int partial,
 	else {
 		authmsg = authenticated ? "Accepted" : "Failed";
 		if (authenticated)
-			BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK);
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_OK, "ssh");
 	}
 
 	authlog("%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s",
@@ -664,7 +664,7 @@ getpwnamallow(const char *user)
 	}
 #endif
 	if (pw == NULL) {
-		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+		BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user);
 		logit("Invalid user %.100s from %.100s port %d",
 		    user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
 #ifdef CUSTOM_FAILED_LOGIN

crypto/openssh/auth1.c

@@ -338,7 +338,7 @@ do_authloop(Authctxt *authctxt)
 			char *msg;
 			size_t len;
 
-			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
 			error("Access denied for user %s by PAM account "
 			    "configuration", authctxt->user);
 			len = buffer_len(&loginmsg);
@@ -364,6 +364,7 @@ do_authloop(Authctxt *authctxt)
 		if (authenticated)
 			return;
 
+		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
 		if (++authctxt->failures >= options.max_authtries) {
 #ifdef SSH_AUDIT_EVENTS
 			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
@@ -406,7 +407,7 @@ do_authentication(Authctxt *authctxt)
 	else {
 		debug("do_authentication: invalid user %s", user);
 		authctxt->pw = fakepw();
-		BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+		BLACKLIST_NOTIFY(BLACKLIST_BAD_USER, user);
 	}
 
 	/* Configuration may have changed as a result of Match */

crypto/openssh/auth2.c

@@ -245,7 +245,6 @@ 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
@@ -386,8 +385,10 @@ userauth_finish(Authctxt *authctxt, int authenticated, const char *method,
 
 		/* Allow initial try of "none" auth without failure penalty */
 		if (!partial && !authctxt->server_caused_failure &&
-		    (authctxt->attempt > 1 || strcmp(method, "none") != 0))
+		    (authctxt->attempt > 1 || strcmp(method, "none") != 0)) {
 			authctxt->failures++;
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
+		}
 		if (authctxt->failures >= options.max_authtries) {
 #ifdef SSH_AUDIT_EVENTS
 			PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));

crypto/openssh/blacklist.c

@@ -46,8 +46,8 @@
 #include "log.h"
 #include "misc.h"
 #include "servconf.h"
-#include "blacklist_client.h"
 #include <blacklist.h>
+#include "blacklist_client.h"
 
 static struct blacklist *blstate = NULL;
 
@@ -88,10 +88,10 @@ blacklist_init(void)
 }
 
 void
-blacklist_notify(int action)
+blacklist_notify(int action, const char *msg)
 {
 
 	if (blstate != NULL && packet_connection_is_on_socket())
 		(void)blacklist_r(blstate, action,
-		packet_get_connection_in(), "ssh");
+		packet_get_connection_in(), msg);
 }

crypto/openssh/blacklist_client.h

@@ -34,22 +34,26 @@
 #ifndef BLACKLIST_CLIENT_H
 #define BLACKLIST_CLIENT_H
 
+#ifndef BLACKLIST_API_ENUM
 enum {
 	BLACKLIST_AUTH_OK = 0,
-	BLACKLIST_AUTH_FAIL
+	BLACKLIST_AUTH_FAIL,
+	BLACKLIST_ABUSIVE_BEHAVIOR,
+	BLACKLIST_BAD_USER
 };
+#endif
 
 #ifdef USE_BLACKLIST
 void blacklist_init(void);
-void blacklist_notify(int);
+void blacklist_notify(int, const char *);
 
 #define BLACKLIST_INIT() blacklist_init()
-#define BLACKLIST_NOTIFY(x) blacklist_notify(x)
+#define BLACKLIST_NOTIFY(x,msg) blacklist_notify(x,msg)
 
 #else
 
 #define BLACKLIST_INIT()
-#define BLACKLIST_NOTIFY(x)
+#define BLACKLIST_NOTIFY(x,msg)
 
 #endif
 

crypto/openssh/packet.c

@@ -2104,7 +2104,7 @@ 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);
+			BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
 			logdie("Unable to negotiate with %.200s port %d: %s. "
 			    "Their offer: %s", ssh_remote_ipaddr(ssh),
 			    ssh_remote_port(ssh), ssh_err(r),

crypto/openssh/sshd.c

@@ -371,7 +371,7 @@ grace_alarm_handler(int sig)
 		kill(0, SIGTERM);
 	}
 
-	BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL);
+	BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh");
 
 	/* Log error and exit. */
 	sigdie("Timeout before authentication for %s port %d",