From 610201f50fdb0594e9885594b69e4ee69c71dd08 Mon Sep 17 00:00:00 2001 From: des Date: Sun, 23 Jun 2002 14:01:54 +0000 Subject: Vendor import of OpenSSH 3.3. --- crypto/openssh/auth2-hostbased.c | 182 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 182 insertions(+) create mode 100644 crypto/openssh/auth2-hostbased.c (limited to 'crypto/openssh/auth2-hostbased.c') diff --git a/crypto/openssh/auth2-hostbased.c b/crypto/openssh/auth2-hostbased.c new file mode 100644 index 0000000..2bde7bb --- /dev/null +++ b/crypto/openssh/auth2-hostbased.c @@ -0,0 +1,182 @@ +/* + * Copyright (c) 2000 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" +RCSID("$OpenBSD: auth2-hostbased.c,v 1.2 2002/05/31 11:35:15 markus Exp $"); + +#include "ssh2.h" +#include "xmalloc.h" +#include "packet.h" +#include "buffer.h" +#include "log.h" +#include "servconf.h" +#include "compat.h" +#include "bufaux.h" +#include "auth.h" +#include "key.h" +#include "canohost.h" +#include "monitor_wrap.h" +#include "pathnames.h" + +/* import */ +extern ServerOptions options; +extern u_char *session_id2; +extern int session_id2_len; + +static int +userauth_hostbased(Authctxt *authctxt) +{ + Buffer b; + Key *key = NULL; + char *pkalg, *cuser, *chost, *service; + u_char *pkblob, *sig; + u_int alen, blen, slen; + int pktype; + int authenticated = 0; + + if (!authctxt->valid) { + debug2("userauth_hostbased: disabled because of invalid user"); + return 0; + } + pkalg = packet_get_string(&alen); + pkblob = packet_get_string(&blen); + chost = packet_get_string(NULL); + cuser = packet_get_string(NULL); + sig = packet_get_string(&slen); + + debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d", + cuser, chost, pkalg, slen); +#ifdef DEBUG_PK + debug("signature:"); + buffer_init(&b); + buffer_append(&b, sig, slen); + buffer_dump(&b); + buffer_free(&b); +#endif + pktype = key_type_from_name(pkalg); + if (pktype == KEY_UNSPEC) { + /* this is perfectly legal */ + log("userauth_hostbased: unsupported " + "public key algorithm: %s", pkalg); + goto done; + } + key = key_from_blob(pkblob, blen); + if (key == NULL) { + error("userauth_hostbased: cannot decode key: %s", pkalg); + goto done; + } + if (key->type != pktype) { + error("userauth_hostbased: type mismatch for decoded key " + "(received %d, expected %d)", key->type, pktype); + goto done; + } + service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : + authctxt->service; + buffer_init(&b); + buffer_put_string(&b, session_id2, session_id2_len); + /* reconstruct packet */ + buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); + buffer_put_cstring(&b, authctxt->user); + buffer_put_cstring(&b, service); + buffer_put_cstring(&b, "hostbased"); + buffer_put_string(&b, pkalg, alen); + buffer_put_string(&b, pkblob, blen); + buffer_put_cstring(&b, chost); + buffer_put_cstring(&b, cuser); +#ifdef DEBUG_PK + buffer_dump(&b); +#endif + /* test for allowed key and correct signature */ + authenticated = 0; + if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) && + PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b), + buffer_len(&b))) == 1) + authenticated = 1; + + buffer_clear(&b); +done: + debug2("userauth_hostbased: authenticated %d", authenticated); + if (key != NULL) + key_free(key); + xfree(pkalg); + xfree(pkblob); + xfree(cuser); + xfree(chost); + xfree(sig); + return authenticated; +} + +/* return 1 if given hostkey is allowed */ +int +hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost, + Key *key) +{ + const char *resolvedname, *ipaddr, *lookup; + HostStatus host_status; + int len; + + resolvedname = get_canonical_hostname(options.verify_reverse_mapping); + ipaddr = get_remote_ipaddr(); + + debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s", + chost, resolvedname, ipaddr); + + if (options.hostbased_uses_name_from_packet_only) { + if (auth_rhosts2(pw, cuser, chost, chost) == 0) + return 0; + lookup = chost; + } else { + if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') { + debug2("stripping trailing dot from chost %s", chost); + chost[len - 1] = '\0'; + } + if (strcasecmp(resolvedname, chost) != 0) + log("userauth_hostbased mismatch: " + "client sends %s, but we resolve %s to %s", + chost, ipaddr, resolvedname); + if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0) + return 0; + lookup = resolvedname; + } + debug2("userauth_hostbased: access allowed by auth_rhosts2"); + + host_status = check_key_in_hostfiles(pw, key, lookup, + _PATH_SSH_SYSTEM_HOSTFILE, + options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); + + /* backward compat if no key has been found. */ + if (host_status == HOST_NEW) + host_status = check_key_in_hostfiles(pw, key, lookup, + _PATH_SSH_SYSTEM_HOSTFILE2, + options.ignore_user_known_hosts ? NULL : + _PATH_SSH_USER_HOSTFILE2); + + return (host_status == HOST_OK); +} + +Authmethod method_hostbased = { + "hostbased", + userauth_hostbased, + &options.hostbased_authentication +}; -- cgit v1.1