Foil potential timing attacks by using the correct password hash

instead of "xx".  In practice this means bcrypt() will be used for
non-existent users instead of DES crypt().
Adapted from a patch by Peter Philipp.  OK deraadt@

3 files changed, 17 insertions, 8 deletions

diff --git a/libexec/login_passwd/Makefile b/libexec/login_passwd/Makefile
index 4122b91a6cd..44e4b45ce4d 100644
--- a/libexec/login_passwd/Makefile
+++ b/libexec/login_passwd/Makefile
@@ -1,11 +1,12 @@
-#	$OpenBSD: Makefile,v 1.4 2004/05/12 20:43:44 millert Exp $
+#	$OpenBSD: Makefile,v 1.5 2006/03/09 19:14:10 millert Exp $
 
 PROG=	login_passwd
 MAN=	login_passwd.8
-SRCS=	login.c login_passwd.c
+SRCS=	login.c login_passwd.c pwd_gensalt.c
 DPADD=	${LIBUTIL}
 LDADD=	-lutil
 CFLAGS+=-Wall -DPASSWD
+.PATH:	${.CURDIR}/../../usr.bin/passwd
 
 BINOWN=	root
 BINGRP=	auth
diff --git a/libexec/login_passwd/common.h b/libexec/login_passwd/common.h
index 24aec6cc3de..a430c4d660c 100644
--- a/libexec/login_passwd/common.h
+++ b/libexec/login_passwd/common.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: common.h,v 1.2 2005/04/14 18:33:42 biorn Exp $ */
+/* $OpenBSD: common.h,v 1.3 2006/03/09 19:14:10 millert Exp $ */
 /*-
  * Copyright (c) 2001 Hans Insulander <hin@openbsd.org>.
  * All rights reserved.
@@ -29,10 +29,10 @@
 #define _COMMON_H_
 
 #include <sys/types.h>
-#include <sys/signal.h>
 #include <sys/resource.h>
 #include <sys/param.h>
 
+#include <signal.h>
 #include <syslog.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -56,6 +56,7 @@ extern FILE *back;
 
 #ifdef PASSWD
 int pwd_login(char *, char *, char *, int, char *);
+int pwd_gensalt(char *, int, login_cap_t *, char);
 #endif
 #ifdef KRB5
 int krb5_login(char *, char *, char *, int, int);
diff --git a/libexec/login_passwd/login_passwd.c b/libexec/login_passwd/login_passwd.c
index a2c2601714f..5a54013c50d 100644
--- a/libexec/login_passwd/login_passwd.c
+++ b/libexec/login_passwd/login_passwd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: login_passwd.c,v 1.8 2004/03/10 21:30:27 millert Exp $	*/
+/*	$OpenBSD: login_passwd.c,v 1.9 2006/03/09 19:14:10 millert Exp $	*/
 
 /*-
  * Copyright (c) 2001 Hans Insulander <hin@openbsd.org>.
@@ -33,8 +33,9 @@ pwd_login(char *username, char *password, char *wheel, int lastchance,
     char *class)
 {
 	struct passwd *pwd;
+	login_cap_t *lc;
 	size_t plen;
-	char *salt;
+	char *salt, saltbuf[_PASSWORD_LEN + 1];
 
 	if (wheel != NULL && strcmp(wheel, "yes") != 0) {
 		fprintf(back, BI_VALUE " errormsg %s\n",
@@ -48,8 +49,14 @@ pwd_login(char *username, char *password, char *wheel, int lastchance,
 	pwd = getpwnam(username);
 	if (pwd)
 		salt = pwd->pw_passwd;
-	else
-		salt = "xx";
+	else {
+		/* no such user, get appropriate salt */
+		if ((lc = login_getclass(NULL)) == NULL ||
+		    pwd_gensalt(saltbuf, sizeof(saltbuf), lc, 'l') == 0)
+			salt = "xx";
+		else
+			salt = saltbuf;
+	}
 
 	setpriority(PRIO_PROCESS, 0, -4);