From 5d35a2f5828cfb0a8579228d80e8bec60c8f8c64 Mon Sep 17 00:00:00 2001 From: Ben Lindstrom Date: Thu, 4 Jul 2002 00:19:40 +0000 Subject: - markus@cvs.openbsd.org 2002/07/03 14:21:05 [ssh-keysign.8 ssh-keysign.c ssh.c ssh_config] re-enable ssh-keysign's sbit, but make ssh-keysign read /etc/ssh/ssh_config and exit if HostbasedAuthentication is disabled globally. based on discussions with deraadt, itojun and sommerfeld; ok itojun@ --- ChangeLog | 8 +++++++- ssh-keysign.8 | 17 ++++++++++++++++- ssh-keysign.c | 16 +++++++++++++++- ssh.c | 5 +++-- ssh_config | 3 ++- 5 files changed, 43 insertions(+), 6 deletions(-) diff --git a/ChangeLog b/ChangeLog index 03d11bb23..1e5ce7adf 100644 --- a/ChangeLog +++ b/ChangeLog @@ -50,6 +50,12 @@ use RSA_blinding_on() for rsa hostkeys (suggested by Bill Sommerfeld) in order to avoid a possible Kocher timing attack pointed out by Charles Hannum; ok provos@ + - markus@cvs.openbsd.org 2002/07/03 14:21:05 + [ssh-keysign.8 ssh-keysign.c ssh.c ssh_config] + re-enable ssh-keysign's sbit, but make ssh-keysign read + /etc/ssh/ssh_config and exit if HostbasedAuthentication is disabled + globally. based on discussions with deraadt, itojun and sommerfeld; + ok itojun@ 20020702 - (djm) Use PAM_MSG_MEMBER for PAM_TEXT_INFO messages, use xmalloc & @@ -1258,4 +1264,4 @@ - (stevesk) entropy.c: typo in debug message - (djm) ssh-keygen -i needs seeded RNG; report from markus@ -$Id: ChangeLog,v 1.2328 2002/07/04 00:17:33 mouring Exp $ +$Id: ChangeLog,v 1.2329 2002/07/04 00:19:40 mouring Exp $ diff --git a/ssh-keysign.8 b/ssh-keysign.8 index ab2cf21ba..cea4a8244 100644 --- a/ssh-keysign.8 +++ b/ssh-keysign.8 @@ -1,4 +1,4 @@ -.\" $OpenBSD: ssh-keysign.8,v 1.2 2002/06/10 16:56:30 stevesk Exp $ +.\" $OpenBSD: ssh-keysign.8,v 1.3 2002/07/03 14:21:05 markus Exp $ .\" .\" Copyright (c) 2002 Markus Friedl. All rights reserved. .\" @@ -36,6 +36,16 @@ is used by .Xr ssh 1 to access the local host keys and generate the digital signature required during hostbased authentication with SSH protocol version 2. +.Pp +.Nm +is disabled by default and can only be enabled in the +the global client configuration file +.Pa /etc/ssh/ssh_config +by setting +.Cm HostbasedAuthentication +to +.Dq yes . +.Pp .Nm is not intended to be invoked by the user, but from .Xr ssh 1 . @@ -46,6 +56,10 @@ and for more information about hostbased authentication. .Sh FILES .Bl -tag -width Ds +.It Pa /etc/ssh/ssh_config +Controls whether +.Nm +is enabled. .It Pa /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key These files contain the private parts of the host keys used to generate the digital signature. They @@ -58,6 +72,7 @@ must be set-uid root if hostbased authentication is used. .Sh SEE ALSO .Xr ssh 1 , .Xr ssh-keygen 1 , +.Xr ssh_config 5 , .Xr sshd 8 .Sh AUTHORS Markus Friedl diff --git a/ssh-keysign.c b/ssh-keysign.c index bed2b9874..06d28efa8 100644 --- a/ssh-keysign.c +++ b/ssh-keysign.c @@ -22,7 +22,7 @@ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" -RCSID("$OpenBSD: ssh-keysign.c,v 1.6 2002/07/03 09:55:38 markus Exp $"); +RCSID("$OpenBSD: ssh-keysign.c,v 1.7 2002/07/03 14:21:05 markus Exp $"); #include #include @@ -30,6 +30,7 @@ RCSID("$OpenBSD: ssh-keysign.c,v 1.6 2002/07/03 09:55:38 markus Exp $"); #include "log.h" #include "key.h" +#include "ssh.h" #include "ssh2.h" #include "misc.h" #include "xmalloc.h" @@ -39,6 +40,9 @@ RCSID("$OpenBSD: ssh-keysign.c,v 1.6 2002/07/03 09:55:38 markus Exp $"); #include "msg.h" #include "canohost.h" #include "pathnames.h" +#include "readconf.h" + +uid_t original_real_uid; /* XXX readconf.c needs this */ #ifdef HAVE___PROGNAME extern char *__progname; @@ -136,6 +140,7 @@ int main(int argc, char **argv) { Buffer b; + Options options; Key *keys[2], *key; struct passwd *pw; int key_fd[2], i, found, version = 2, fd; @@ -158,6 +163,15 @@ main(int argc, char **argv) log_init("ssh-keysign", SYSLOG_LEVEL_DEBUG3, SYSLOG_FACILITY_AUTH, 0); #endif + /* verify that ssh-keysign is enabled by the admin */ + original_real_uid = getuid(); /* XXX readconf.c needs this */ + initialize_options(&options); + (void)read_config_file(_PATH_HOST_CONFIG_FILE, "", &options); + fill_default_options(&options); + if (options.hostbased_authentication != 1) + fatal("Hostbased authentication not enabled in %s", + _PATH_HOST_CONFIG_FILE); + if (key_fd[0] == -1 && key_fd[1] == -1) fatal("could not open any host key"); diff --git a/ssh.c b/ssh.c index 67d297c0a..77e709daf 100644 --- a/ssh.c +++ b/ssh.c @@ -40,7 +40,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: ssh.c,v 1.180 2002/06/30 21:59:45 deraadt Exp $"); +RCSID("$OpenBSD: ssh.c,v 1.181 2002/07/03 14:21:05 markus Exp $"); #include #include @@ -649,7 +649,8 @@ again: _PATH_HOST_RSA_KEY_FILE, "", NULL); PRIV_END; - if (sensitive_data.keys[0] == NULL && + if (options.hostbased_authentication == 1 && + sensitive_data.keys[0] == NULL && sensitive_data.keys[1] == NULL && sensitive_data.keys[2] == NULL) { sensitive_data.keys[1] = key_load_public( diff --git a/ssh_config b/ssh_config index ef31d4336..94cffbf39 100644 --- a/ssh_config +++ b/ssh_config @@ -1,4 +1,4 @@ -# $OpenBSD: ssh_config,v 1.15 2002/06/20 20:03:34 stevesk Exp $ +# $OpenBSD: ssh_config,v 1.16 2002/07/03 14:21:05 markus Exp $ # This is the ssh client system-wide configuration file. See # ssh_config(5) for more information. This file provides defaults for @@ -22,6 +22,7 @@ # RhostsRSAAuthentication no # RSAAuthentication yes # PasswordAuthentication yes +# HostbasedAuthentication no # BatchMode no # CheckHostIP yes # StrictHostKeyChecking ask -- cgit v1.2.3