1 /* $OpenBSD: auth-rh-rsa.c,v 1.43 2010/03/04 10:36:03 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo (at) cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo (at) cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Rhosts or /etc/hosts.equiv authentication combined with RSA host 7 * authentication. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 */ 15 16 #include "includes.h" 17 18 #include <sys/types.h> 19 20 #include <pwd.h> 21 #include <stdarg.h> 22 23 #include "packet.h" 24 #include "uidswap.h" 25 #include "log.h" 26 #include "buffer.h" 27 #include "servconf.h" 28 #include "key.h" 29 #include "hostfile.h" 30 #include "pathnames.h" 31 #include "auth.h" 32 #include "canohost.h" 33 #ifdef GSSAPI 34 #include "ssh-gss.h" 35 #endif 36 #include "monitor_wrap.h" 37 38 /* import */ 39 extern ServerOptions options; 40 41 int 42 auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost, 43 Key *client_host_key) 44 { 45 HostStatus host_status; 46 47 if (auth_key_is_revoked(client_host_key)) 48 return 0; 49 50 /* Check if we would accept it using rhosts authentication. */ 51 if (!auth_rhosts(pw, cuser)) 52 return 0; 53 54 host_status = check_key_in_hostfiles(pw, client_host_key, 55 chost, _PATH_SSH_SYSTEM_HOSTFILE, 56 options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); 57 58 return (host_status == HOST_OK); 59 } 60 61 /* 62 * Tries to authenticate the user using the .rhosts file and the host using 63 * its host key. Returns true if authentication succeeds. 64 */ 65 int 66 auth_rhosts_rsa(Authctxt *authctxt, char *cuser, Key *client_host_key) 67 { 68 char *chost; 69 struct passwd *pw = authctxt->pw; 70 71 debug("Trying rhosts with RSA host authentication for client user %.100s", 72 cuser); 73 74 if (!authctxt->valid || client_host_key == NULL || 75 client_host_key->rsa == NULL) 76 return 0; 77 78 chost = (char *)get_canonical_hostname(options.use_dns); 79 debug("Rhosts RSA authentication: canonical host %.900s", chost); 80 81 if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) { 82 debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); 83 packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); 84 return 0; 85 } 86 /* A matching host key was found and is known. */ 87 88 /* Perform the challenge-response dialog with the client for the host key. */ 89 if (!auth_rsa_challenge_dialog(client_host_key)) { 90 logit("Client on %.800s failed to respond correctly to host authentication.", 91 chost); 92 return 0; 93 } 94 /* 95 * We have authenticated the user using .rhosts or /etc/hosts.equiv, 96 * and the host using RSA. We accept the authentication. 97 */ 98 99 verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", 100 pw->pw_name, cuser, chost); 101 packet_send_debug("Rhosts with RSA host authentication accepted."); 102 return 1; 103 } 104
