1d059297112922cabb0c674840589be8db821fd9aAdam Langley/* $OpenBSD: auth-rh-rsa.c,v 1.44 2014/07/15 15:54:14 millert Exp $ */ 2bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman/* 3bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * Author: Tatu Ylonen <ylo@cs.hut.fi> 4bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * All rights reserved 6bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * Rhosts or /etc/hosts.equiv authentication combined with RSA host 7bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * authentication. 8bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * 9bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * As far as I am concerned, the code I have written for this software 10bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * can be used freely for any purpose. Any derived versions of this 11bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * software must be clearly marked as such, and if the derived work is 12bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * incompatible with the protocol description in the RFC file, it must be 13bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * called by a name other than "ssh" or "Secure Shell". 14bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman */ 15bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 16bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "includes.h" 17bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 18d059297112922cabb0c674840589be8db821fd9aAdam Langley#ifdef WITH_SSH1 19d059297112922cabb0c674840589be8db821fd9aAdam Langley 20bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include <sys/types.h> 21bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 22bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include <pwd.h> 23bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include <stdarg.h> 24bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 25bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "packet.h" 26bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "uidswap.h" 27bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "log.h" 28bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "buffer.h" 29d059297112922cabb0c674840589be8db821fd9aAdam Langley#include "misc.h" 30bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "servconf.h" 31bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "key.h" 32bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "hostfile.h" 33bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "pathnames.h" 34bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "auth.h" 35bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "canohost.h" 36bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#ifdef GSSAPI 37bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "ssh-gss.h" 38bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#endif 39bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman#include "monitor_wrap.h" 40bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 41bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman/* import */ 42bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartmanextern ServerOptions options; 43bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 44bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartmanint 45bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartmanauth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost, 46bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman Key *client_host_key) 47bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman{ 48bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman HostStatus host_status; 49bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 50bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman if (auth_key_is_revoked(client_host_key)) 51bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 0; 52bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 53bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman /* Check if we would accept it using rhosts authentication. */ 54bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman if (!auth_rhosts(pw, cuser)) 55bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 0; 56bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 57bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman host_status = check_key_in_hostfiles(pw, client_host_key, 58bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman chost, _PATH_SSH_SYSTEM_HOSTFILE, 59bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); 60bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 61bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return (host_status == HOST_OK); 62bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman} 63bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 64bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman/* 65bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * Tries to authenticate the user using the .rhosts file and the host using 66bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * its host key. Returns true if authentication succeeds. 67bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman */ 68bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartmanint 69bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartmanauth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key) 70bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman{ 71bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman char *chost; 72bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman struct passwd *pw = authctxt->pw; 73bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 74bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman debug("Trying rhosts with RSA host authentication for client user %.100s", 75bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman cuser); 76bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 77bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman if (!authctxt->valid || client_host_key == NULL || 78bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman client_host_key->rsa == NULL) 79bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 0; 80bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 81bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman chost = (char *)get_canonical_hostname(options.use_dns); 82bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman debug("Rhosts RSA authentication: canonical host %.900s", chost); 83bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 84bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) { 85bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); 86bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); 87bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 0; 88bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman } 89bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman /* A matching host key was found and is known. */ 90bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 91bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman /* Perform the challenge-response dialog with the client for the host key. */ 92bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman if (!auth_rsa_challenge_dialog(client_host_key)) { 93bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman logit("Client on %.800s failed to respond correctly to host authentication.", 94bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman chost); 95bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 0; 96bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman } 97bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman /* 98bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * We have authenticated the user using .rhosts or /etc/hosts.equiv, 99bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman * and the host using RSA. We accept the authentication. 100bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman */ 101bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman 102bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", 103bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman pw->pw_name, cuser, chost); 104bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman packet_send_debug("Rhosts with RSA host authentication accepted."); 105bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman return 1; 106bd77cf78387b72b7b3ea870459077672bf75c3b5Greg Hartman} 107d059297112922cabb0c674840589be8db821fd9aAdam Langley 108d059297112922cabb0c674840589be8db821fd9aAdam Langley#endif /* WITH_SSH1 */ 109