crypto/external/bsd/openssh/dist/auth-rh-rsa.c

   1 /*      $NetBSD$        */
   2 /* $OpenBSD: auth-rh-rsa.c,v 1.42 2006/08/03 03:34:41 deraadt Exp $ */
   3 /*
   4  * Author: Tatu Ylonen <ylo@cs.hut.fi>
   5  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
   6  *                    All rights reserved
   7  * Rhosts or /etc/hosts.equiv authentication combined with RSA host
   8  * authentication.
   9  *
  10  * As far as I am concerned, the code I have written for this software
  11  * can be used freely for any purpose.  Any derived versions of this
  12  * software must be clearly marked as such, and if the derived work is
  13  * incompatible with the protocol description in the RFC file, it must be
  14  * called by a name other than "ssh" or "Secure Shell".
  15  */
  16
  17 #include "includes.h"
  18 __RCSID("$NetBSD: auth-rh-rsa.c,v 1.6 2006/09/28 21:22:14 christos Exp $");
  19 #include <sys/types.h>
  20
  21 #include <pwd.h>
  22 #include <stdarg.h>
  23
  24 #include "packet.h"
  25 #include "uidswap.h"
  26 #include "log.h"
  27 #include "buffer.h"
  28 #include "servconf.h"
  29 #include "key.h"
  30 #include "hostfile.h"
  31 #include "pathnames.h"
  32 #include "auth.h"
  33 #include "canohost.h"
  34 #ifdef GSSAPI
  35 #include "ssh-gss.h"
  36 #endif
  37 #include "monitor_wrap.h"
  38
  39 /* import */
  40 extern ServerOptions options;
  41
  42 int
  43 auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost,
  44     Key *client_host_key)
  45 {
  46         HostStatus host_status;
  47
  48         /* Check if we would accept it using rhosts authentication. */
  49         if (!auth_rhosts(pw, cuser))
  50                 return 0;
  51
  52         host_status = check_key_in_hostfiles(pw, client_host_key,
  53             chost, _PATH_SSH_SYSTEM_HOSTFILE,
  54             options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
  55
  56         return (host_status == HOST_OK);
  57 }
  58
  59 /*
  60  * Tries to authenticate the user using the .rhosts file and the host using
  61  * its host key.  Returns true if authentication succeeds.
  62  */
  63 int
  64 auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key)
  65 {
  66         char *chost;
  67         struct passwd *pw = authctxt->pw;
  68
  69         debug("Trying rhosts with RSA host authentication for client user %.100s",
  70             cuser);
  71
  72         if (!authctxt->valid || client_host_key == NULL ||
  73             client_host_key->rsa == NULL)
  74                 return 0;
  75
  76         chost = (char *)get_canonical_hostname(options.use_dns);
  77         debug("Rhosts RSA authentication: canonical host %.900s", chost);
  78
  79         if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) {
  80                 debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
  81                 packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
  82                 return 0;
  83         }
  84         /* A matching host key was found and is known. */
  85
  86         /* Perform the challenge-response dialog with the client for the host key. */
  87         if (!auth_rsa_challenge_dialog(client_host_key)) {
  88                 logit("Client on %.800s failed to respond correctly to host authentication.",
  89                     chost);
  90                 return 0;
  91         }
  92         /*
  93          * We have authenticated the user using .rhosts or /etc/hosts.equiv,
  94          * and the host using RSA. We accept the authentication.
  95          */
  96
  97         verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
  98             pw->pw_name, cuser, chost);
  99         packet_send_debug("Rhosts with RSA host authentication accepted.");
 100         return 1;
 101 }