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/* $OpenBSD: auth-rh-rsa.c,v 1.42 2006/08/03 03:34:41 deraadt Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Rhosts or /etc/hosts.equiv authentication combined with RSA host
* authentication.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*/
#include <sys/types.h>
#include <pwd.h>
#include <stdarg.h>
#include "packet.h"
#include "uidswap.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "key.h"
#include "hostfile.h"
#include "pathnames.h"
#include "auth.h"
#include "canohost.h"
#ifdef GSSAPI
#include "ssh-gss.h"
#endif
#include "monitor_wrap.h"
/* import */
extern ServerOptions options;
int
auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
Key *client_host_key)
{
HostStatus host_status;
/* Check if we would accept it using rhosts authentication. */
if (!auth_rhosts(pw, cuser))
return 0;
host_status = check_key_in_hostfiles(pw, client_host_key,
chost, _PATH_SSH_SYSTEM_HOSTFILE,
options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
return (host_status == HOST_OK);
}
/*
* Tries to authenticate the user using the .rhosts file and the host using
* its host key. Returns true if authentication succeeds.
*/
int
auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key)
{
char *chost;
struct passwd *pw = authctxt->pw;
debug("Trying rhosts with RSA host authentication for client user %.100s",
cuser);
if (!authctxt->valid || client_host_key == NULL ||
client_host_key->rsa == NULL)
return 0;
chost = (char *)get_canonical_hostname(options.use_dns);
debug("Rhosts RSA authentication: canonical host %.900s", chost);
if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) {
debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
return 0;
}
/* A matching host key was found and is known. */
/* Perform the challenge-response dialog with the client for the host key. */
if (!auth_rsa_challenge_dialog(client_host_key)) {
logit("Client on %.800s failed to respond correctly to host authentication.",
chost);
return 0;
}
/*
* We have authenticated the user using .rhosts or /etc/hosts.equiv,
* and the host using RSA. We accept the authentication.
*/
verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
pw->pw_name, cuser, chost);
packet_send_debug("Rhosts with RSA host authentication accepted.");
return 1;
}
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