X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/8efc0c151a0f57612e1aa0abb5b7d536db4cf76a..94ec8c6bb36d0681d3d8e61de9b260b159772799:/auth-rh-rsa.c diff --git a/auth-rh-rsa.c b/auth-rh-rsa.c index 9c71715e..3070c9d4 100644 --- a/auth-rh-rsa.c +++ b/auth-rh-rsa.c @@ -1,83 +1,113 @@ /* - -auth-rh-rsa.c - -Author: Tatu Ylonen - -Copyright (c) 1995 Tatu Ylonen , Espoo, Finland - All rights reserved - -Created: Sun May 7 03:08:06 1995 ylo - -Rhosts or /etc/hosts.equiv authentication combined with RSA host -authentication. - -*/ + * Author: Tatu Ylonen + * Copyright (c) 1995 Tatu Ylonen , 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 "includes.h" -RCSID("$Id$"); +RCSID("$OpenBSD: auth-rh-rsa.c,v 1.17 2000/10/03 18:03:03 markus Exp $"); #include "packet.h" #include "ssh.h" #include "xmalloc.h" #include "uidswap.h" +#include "servconf.h" -/* Tries to authenticate the user using the .rhosts file and the host using - its host key. Returns true if authentication succeeds. - .rhosts and .shosts will be ignored if ignore_rhosts is non-zero. */ +#include +#include +#include "key.h" +#include "hostfile.h" + +/* + * 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(struct passwd *pw, const char *client_user, - unsigned int client_host_key_bits, - BIGNUM *client_host_key_e, BIGNUM *client_host_key_n, - int ignore_rhosts, int strict_modes) +int +auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key) { - const char *canonical_hostname; - HostStatus host_status; - BIGNUM *ke, *kn; - - debug("Trying rhosts with RSA host authentication for %.100s", client_user); - - /* Check if we would accept it using rhosts authentication. */ - if (!auth_rhosts(pw, client_user, ignore_rhosts, strict_modes)) - return 0; - - canonical_hostname = get_canonical_hostname(); - - debug("Rhosts RSA authentication: canonical host %.900s", - canonical_hostname); - - /* Check if we know the host and its host key. */ - /* Check system-wide host file. */ - ke = BN_new(); - kn = BN_new(); - host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, - client_host_key_bits, client_host_key_e, - client_host_key_n, ke, kn); - BN_free(ke); - BN_free(kn); - if (host_status != HOST_OK) { - /* The host key was not found. */ - 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_bits, - client_host_key_e, client_host_key_n)) - { - log("Client on %.800s failed to respond correctly to host authentication.", - canonical_hostname); - return 0; - } - - /* We have authenticated the user using .rhosts or /etc/hosts.equiv, and - the host using RSA. We accept the authentication. */ - - log("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", - pw->pw_name, client_user, canonical_hostname); - packet_send_debug("Rhosts with RSA host authentication accepted."); - return 1; + extern ServerOptions options; + const char *canonical_hostname; + HostStatus host_status; + Key *client_key, *found; + + debug("Trying rhosts with RSA host authentication for client user %.100s", client_user); + + if (pw == NULL || client_host_key == NULL) + return 0; + + /* Check if we would accept it using rhosts authentication. */ + if (!auth_rhosts(pw, client_user)) + return 0; + + canonical_hostname = get_canonical_hostname(); + + debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname); + + /* wrap the RSA key into a 'generic' key */ + client_key = key_new(KEY_RSA); + BN_copy(client_key->rsa->e, client_host_key->e); + BN_copy(client_key->rsa->n, client_host_key->n); + found = key_new(KEY_RSA); + + /* Check if we know the host and its host key. */ + host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, + client_key, found); + + /* Check user host file unless ignored. */ + if (host_status != HOST_OK && !options.ignore_user_known_hosts) { + struct stat st; + char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid); + /* + * Check file permissions of SSH_USER_HOSTFILE, auth_rsa() + * did already check pw->pw_dir, but there is a race XXX + */ + if (options.strict_modes && + (stat(user_hostfile, &st) == 0) && + ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || + (st.st_mode & 022) != 0)) { + log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s", + pw->pw_name, user_hostfile); + } else { + /* XXX race between stat and the following open() */ + temporarily_use_uid(pw->pw_uid); + host_status = check_host_in_hostfile(user_hostfile, canonical_hostname, + client_key, found); + restore_uid(); + } + xfree(user_hostfile); + } + key_free(client_key); + key_free(found); + + if (host_status != HOST_OK) { + 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)) { + log("Client on %.800s failed to respond correctly to host authentication.", + canonical_hostname); + 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, client_user, canonical_hostname); + packet_send_debug("Rhosts with RSA host authentication accepted."); + return 1; }