This release fixes a number of security bugs and has minor new features and bug fixes. Security fixes, from the release notes (https://www.openssh.com/txt/release-9.3): This release contains fixes for a security problem and a memory safety problem. The memory safety problem is not believed to be exploitable, but we report most network-reachable memory faults as security bugs. * ssh-add(1): when adding smartcard keys to ssh-agent(1) with the per-hop destination constraints (ssh-add -h ...) added in OpenSSH 8.9, a logic error prevented the constraints from being communicated to the agent. This resulted in the keys being added without constraints. The common cases of non-smartcard keys and keys without destination constraints are unaffected. This problem was reported by Luci Stanescu. * ssh(1): Portable OpenSSH provides an implementation of the getrrsetbyname(3) function if the standard library does not provide it, for use by the VerifyHostKeyDNS feature. A specifically crafted DNS response could cause this function to perform an out-of-bounds read of adjacent stack data, but this condition does not appear to be exploitable beyond denial-of- service to the ssh(1) client. The getrrsetbyname(3) replacement is only included if the system's standard library lacks this function and portable OpenSSH was not compiled with the ldns library (--with-ldns). getrrsetbyname(3) is only invoked if using VerifyHostKeyDNS to fetch SSHFP records. This problem was found by the Coverity static analyzer. Sponsored by: The FreeBSD Foundation
2358 lines
65 KiB
C
2358 lines
65 KiB
C
/* $OpenBSD: sshconnect2.c,v 1.366 2023/03/09 07:11:05 dtucker Exp $ */
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/*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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* Copyright (c) 2008 Damien Miller. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/wait.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <netdb.h>
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#include <pwd.h>
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#include <signal.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdarg.h>
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#include <unistd.h>
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#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
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#include <vis.h>
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#endif
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#include "openbsd-compat/sys-queue.h"
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#include "xmalloc.h"
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#include "ssh.h"
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#include "ssh2.h"
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#include "sshbuf.h"
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#include "packet.h"
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#include "compat.h"
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#include "cipher.h"
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#include "sshkey.h"
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#include "kex.h"
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#include "sshconnect.h"
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#include "authfile.h"
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#include "dh.h"
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#include "authfd.h"
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#include "log.h"
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#include "misc.h"
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#include "readconf.h"
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#include "match.h"
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#include "dispatch.h"
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#include "canohost.h"
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#include "msg.h"
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#include "pathnames.h"
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#include "uidswap.h"
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#include "hostfile.h"
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#include "ssherr.h"
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#include "utf8.h"
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#include "ssh-sk.h"
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#include "sk-api.h"
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#ifdef GSSAPI
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#include "ssh-gss.h"
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#endif
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/* import */
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extern char *client_version_string;
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extern char *server_version_string;
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extern Options options;
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/*
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* SSH2 key exchange
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*/
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static char *xxx_host;
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static struct sockaddr *xxx_hostaddr;
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static const struct ssh_conn_info *xxx_conn_info;
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static int
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verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh)
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{
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int r;
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if ((r = sshkey_check_rsa_length(hostkey,
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options.required_rsa_size)) != 0)
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fatal_r(r, "Bad server host key");
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if (verify_host_key(xxx_host, xxx_hostaddr, hostkey,
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xxx_conn_info) == -1)
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fatal("Host key verification failed.");
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return 0;
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}
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/* Returns the first item from a comma-separated algorithm list */
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static char *
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first_alg(const char *algs)
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{
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char *ret, *cp;
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ret = xstrdup(algs);
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if ((cp = strchr(ret, ',')) != NULL)
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*cp = '\0';
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return ret;
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}
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static char *
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order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port,
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const struct ssh_conn_info *cinfo)
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{
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char *oavail = NULL, *avail = NULL, *first = NULL, *last = NULL;
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char *alg = NULL, *hostname = NULL, *ret = NULL, *best = NULL;
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size_t maxlen;
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struct hostkeys *hostkeys = NULL;
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int ktype;
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u_int i;
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/* Find all hostkeys for this hostname */
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get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
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hostkeys = init_hostkeys();
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for (i = 0; i < options.num_user_hostfiles; i++)
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load_hostkeys(hostkeys, hostname, options.user_hostfiles[i], 0);
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for (i = 0; i < options.num_system_hostfiles; i++) {
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load_hostkeys(hostkeys, hostname,
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options.system_hostfiles[i], 0);
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}
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if (options.known_hosts_command != NULL) {
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load_hostkeys_command(hostkeys, options.known_hosts_command,
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"ORDER", cinfo, NULL, host);
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}
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/*
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* If a plain public key exists that matches the type of the best
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* preference HostkeyAlgorithms, then use the whole list as is.
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* Note that we ignore whether the best preference algorithm is a
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* certificate type, as sshconnect.c will downgrade certs to
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* plain keys if necessary.
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*/
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best = first_alg(options.hostkeyalgorithms);
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if (lookup_key_in_hostkeys_by_type(hostkeys,
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sshkey_type_plain(sshkey_type_from_name(best)),
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sshkey_ecdsa_nid_from_name(best), NULL)) {
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debug3_f("have matching best-preference key type %s, "
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"using HostkeyAlgorithms verbatim", best);
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ret = xstrdup(options.hostkeyalgorithms);
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goto out;
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}
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/*
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* Otherwise, prefer the host key algorithms that match known keys
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* while keeping the ordering of HostkeyAlgorithms as much as possible.
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*/
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oavail = avail = xstrdup(options.hostkeyalgorithms);
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maxlen = strlen(avail) + 1;
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first = xmalloc(maxlen);
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last = xmalloc(maxlen);
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*first = *last = '\0';
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#define ALG_APPEND(to, from) \
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do { \
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if (*to != '\0') \
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strlcat(to, ",", maxlen); \
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strlcat(to, from, maxlen); \
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} while (0)
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while ((alg = strsep(&avail, ",")) && *alg != '\0') {
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if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC)
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fatal_f("unknown alg %s", alg);
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/*
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* If we have a @cert-authority marker in known_hosts then
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* prefer all certificate algorithms.
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*/
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if (sshkey_type_is_cert(ktype) &&
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lookup_marker_in_hostkeys(hostkeys, MRK_CA)) {
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ALG_APPEND(first, alg);
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continue;
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}
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/* If the key appears in known_hosts then prefer it */
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if (lookup_key_in_hostkeys_by_type(hostkeys,
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sshkey_type_plain(ktype),
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sshkey_ecdsa_nid_from_name(alg), NULL)) {
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ALG_APPEND(first, alg);
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continue;
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}
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/* Otherwise, put it last */
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ALG_APPEND(last, alg);
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}
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#undef ALG_APPEND
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xasprintf(&ret, "%s%s%s", first,
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(*first == '\0' || *last == '\0') ? "" : ",", last);
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if (*first != '\0')
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debug3_f("prefer hostkeyalgs: %s", first);
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else
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debug3_f("no algorithms matched; accept original");
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out:
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free(best);
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free(first);
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free(last);
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free(hostname);
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free(oavail);
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free_hostkeys(hostkeys);
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return ret;
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}
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void
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ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port,
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const struct ssh_conn_info *cinfo)
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{
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char *myproposal[PROPOSAL_MAX];
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char *s, *all_key, *hkalgs = NULL;
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int r, use_known_hosts_order = 0;
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xxx_host = host;
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xxx_hostaddr = hostaddr;
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xxx_conn_info = cinfo;
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if (options.rekey_limit || options.rekey_interval)
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ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
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options.rekey_interval);
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/*
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* If the user has not specified HostkeyAlgorithms, or has only
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* appended or removed algorithms from that list then prefer algorithms
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* that are in the list that are supported by known_hosts keys.
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*/
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if (options.hostkeyalgorithms == NULL ||
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options.hostkeyalgorithms[0] == '-' ||
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options.hostkeyalgorithms[0] == '+')
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use_known_hosts_order = 1;
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/* Expand or fill in HostkeyAlgorithms */
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all_key = sshkey_alg_list(0, 0, 1, ',');
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if ((r = kex_assemble_names(&options.hostkeyalgorithms,
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kex_default_pk_alg(), all_key)) != 0)
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fatal_fr(r, "kex_assemble_namelist");
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free(all_key);
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if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
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fatal_f("kex_names_cat");
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if (use_known_hosts_order)
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hkalgs = order_hostkeyalgs(host, hostaddr, port, cinfo);
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kex_proposal_populate_entries(ssh, myproposal, s, options.ciphers,
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options.macs, compression_alg_list(options.compression),
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hkalgs ? hkalgs : options.hostkeyalgorithms);
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free(hkalgs);
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/* start key exchange */
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if ((r = kex_setup(ssh, myproposal)) != 0)
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fatal_r(r, "kex_setup");
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#ifdef WITH_OPENSSL
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ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
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ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
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ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
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ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
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ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
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ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
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ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
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# ifdef OPENSSL_HAS_ECC
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ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
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# endif
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#endif
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ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
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ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
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ssh->kex->verify_host_key=&verify_host_key_callback;
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ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done);
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/* remove ext-info from the KEX proposals for rekeying */
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free(myproposal[PROPOSAL_KEX_ALGS]);
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myproposal[PROPOSAL_KEX_ALGS] =
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compat_kex_proposal(ssh, options.kex_algorithms);
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if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0)
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fatal_r(r, "kex_prop2buf");
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#ifdef DEBUG_KEXDH
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/* send 1st encrypted/maced/compressed message */
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if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
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(r = sshpkt_put_cstring(ssh, "markus")) != 0 ||
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(r = sshpkt_send(ssh)) != 0 ||
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(r = ssh_packet_write_wait(ssh)) != 0)
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fatal_fr(r, "send packet");
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#endif
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kex_proposal_free_entries(myproposal);
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}
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/*
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* Authenticate user
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*/
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typedef struct cauthctxt Authctxt;
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typedef struct cauthmethod Authmethod;
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typedef struct identity Identity;
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typedef struct idlist Idlist;
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struct identity {
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TAILQ_ENTRY(identity) next;
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int agent_fd; /* >=0 if agent supports key */
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struct sshkey *key; /* public/private key */
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char *filename; /* comment for agent-only keys */
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int tried;
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int isprivate; /* key points to the private key */
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int userprovided;
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};
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TAILQ_HEAD(idlist, identity);
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struct cauthctxt {
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const char *server_user;
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const char *local_user;
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const char *host;
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const char *service;
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struct cauthmethod *method;
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sig_atomic_t success;
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char *authlist;
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#ifdef GSSAPI
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/* gssapi */
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gss_OID_set gss_supported_mechs;
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u_int mech_tried;
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#endif
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/* pubkey */
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struct idlist keys;
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int agent_fd;
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/* hostbased */
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Sensitive *sensitive;
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char *oktypes, *ktypes;
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const char *active_ktype;
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/* kbd-interactive */
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int info_req_seen;
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int attempt_kbdint;
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/* password */
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int attempt_passwd;
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/* generic */
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void *methoddata;
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};
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struct cauthmethod {
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char *name; /* string to compare against server's list */
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int (*userauth)(struct ssh *ssh);
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void (*cleanup)(struct ssh *ssh);
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int *enabled; /* flag in option struct that enables method */
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int *batch_flag; /* flag in option struct that disables method */
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};
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static int input_userauth_service_accept(int, u_int32_t, struct ssh *);
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static int input_userauth_ext_info(int, u_int32_t, struct ssh *);
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static int input_userauth_success(int, u_int32_t, struct ssh *);
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static int input_userauth_failure(int, u_int32_t, struct ssh *);
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static int input_userauth_banner(int, u_int32_t, struct ssh *);
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static int input_userauth_error(int, u_int32_t, struct ssh *);
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static int input_userauth_info_req(int, u_int32_t, struct ssh *);
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static int input_userauth_pk_ok(int, u_int32_t, struct ssh *);
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static int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *);
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static int userauth_none(struct ssh *);
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static int userauth_pubkey(struct ssh *);
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static int userauth_passwd(struct ssh *);
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static int userauth_kbdint(struct ssh *);
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static int userauth_hostbased(struct ssh *);
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#ifdef GSSAPI
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static int userauth_gssapi(struct ssh *);
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static void userauth_gssapi_cleanup(struct ssh *);
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static int input_gssapi_response(int type, u_int32_t, struct ssh *);
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static int input_gssapi_token(int type, u_int32_t, struct ssh *);
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static int input_gssapi_error(int, u_int32_t, struct ssh *);
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static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
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#endif
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void userauth(struct ssh *, char *);
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static void pubkey_cleanup(struct ssh *);
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static int sign_and_send_pubkey(struct ssh *ssh, Identity *);
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static void pubkey_prepare(struct ssh *, Authctxt *);
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static void pubkey_reset(Authctxt *);
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static struct sshkey *load_identity_file(Identity *);
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static Authmethod *authmethod_get(char *authlist);
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static Authmethod *authmethod_lookup(const char *name);
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static char *authmethods_get(void);
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Authmethod authmethods[] = {
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#ifdef GSSAPI
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{"gssapi-with-mic",
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userauth_gssapi,
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userauth_gssapi_cleanup,
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&options.gss_authentication,
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NULL},
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#endif
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{"hostbased",
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userauth_hostbased,
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NULL,
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&options.hostbased_authentication,
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NULL},
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{"publickey",
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userauth_pubkey,
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NULL,
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&options.pubkey_authentication,
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NULL},
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{"keyboard-interactive",
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userauth_kbdint,
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NULL,
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&options.kbd_interactive_authentication,
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&options.batch_mode},
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{"password",
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userauth_passwd,
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NULL,
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&options.password_authentication,
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&options.batch_mode},
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{"none",
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userauth_none,
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NULL,
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NULL,
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NULL},
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{NULL, NULL, NULL, NULL, NULL}
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};
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|
|
void
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ssh_userauth2(struct ssh *ssh, const char *local_user,
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const char *server_user, char *host, Sensitive *sensitive)
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{
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Authctxt authctxt;
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int r;
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|
|
if (options.preferred_authentications == NULL)
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options.preferred_authentications = authmethods_get();
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|
|
/* setup authentication context */
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|
memset(&authctxt, 0, sizeof(authctxt));
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authctxt.server_user = server_user;
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|
authctxt.local_user = local_user;
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|
authctxt.host = host;
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authctxt.service = "ssh-connection"; /* service name */
|
|
authctxt.success = 0;
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authctxt.method = authmethod_lookup("none");
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|
authctxt.authlist = NULL;
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authctxt.methoddata = NULL;
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authctxt.sensitive = sensitive;
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authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL;
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authctxt.info_req_seen = 0;
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authctxt.attempt_kbdint = 0;
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authctxt.attempt_passwd = 0;
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#if GSSAPI
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|
authctxt.gss_supported_mechs = NULL;
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|
authctxt.mech_tried = 0;
|
|
#endif
|
|
authctxt.agent_fd = -1;
|
|
pubkey_prepare(ssh, &authctxt);
|
|
if (authctxt.method == NULL) {
|
|
fatal_f("internal error: cannot send userauth none request");
|
|
}
|
|
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
|
|
ssh->authctxt = &authctxt;
|
|
ssh_dispatch_init(ssh, &input_userauth_error);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept);
|
|
ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */
|
|
pubkey_cleanup(ssh);
|
|
ssh->authctxt = NULL;
|
|
|
|
ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
|
|
|
|
if (!authctxt.success)
|
|
fatal("Authentication failed.");
|
|
if (ssh_packet_connection_is_on_socket(ssh)) {
|
|
verbose("Authenticated to %s ([%s]:%d) using \"%s\".", host,
|
|
ssh_remote_ipaddr(ssh), ssh_remote_port(ssh),
|
|
authctxt.method->name);
|
|
} else {
|
|
verbose("Authenticated to %s (via proxy) using \"%s\".", host,
|
|
authctxt.method->name);
|
|
}
|
|
}
|
|
|
|
static int
|
|
input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
int r;
|
|
|
|
if (ssh_packet_remaining(ssh) > 0) {
|
|
char *reply;
|
|
|
|
if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0)
|
|
goto out;
|
|
debug2("service_accept: %s", reply);
|
|
free(reply);
|
|
} else {
|
|
debug2("buggy server: service_accept w/o service");
|
|
}
|
|
if ((r = sshpkt_get_end(ssh)) != 0)
|
|
goto out;
|
|
debug("SSH2_MSG_SERVICE_ACCEPT received");
|
|
|
|
/* initial userauth request */
|
|
userauth_none(ssh);
|
|
|
|
ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
|
|
r = 0;
|
|
out:
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh)
|
|
{
|
|
return kex_input_ext_info(type, seqnr, ssh);
|
|
}
|
|
|
|
void
|
|
userauth(struct ssh *ssh, char *authlist)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
|
|
if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
|
|
authctxt->method->cleanup(ssh);
|
|
|
|
free(authctxt->methoddata);
|
|
authctxt->methoddata = NULL;
|
|
if (authlist == NULL) {
|
|
authlist = authctxt->authlist;
|
|
} else {
|
|
free(authctxt->authlist);
|
|
authctxt->authlist = authlist;
|
|
}
|
|
for (;;) {
|
|
Authmethod *method = authmethod_get(authlist);
|
|
if (method == NULL)
|
|
fatal("%s@%s: Permission denied (%s).",
|
|
authctxt->server_user, authctxt->host, authlist);
|
|
authctxt->method = method;
|
|
|
|
/* reset the per method handler */
|
|
ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_PER_METHOD_MIN,
|
|
SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
|
|
|
|
/* and try new method */
|
|
if (method->userauth(ssh) != 0) {
|
|
debug2("we sent a %s packet, wait for reply", method->name);
|
|
break;
|
|
} else {
|
|
debug2("we did not send a packet, disable method");
|
|
method->enabled = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int
|
|
input_userauth_error(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
fatal_f("bad message during authentication: type %d", type);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
char *msg = NULL;
|
|
size_t len;
|
|
int r;
|
|
|
|
debug3_f("entering");
|
|
if ((r = sshpkt_get_cstring(ssh, &msg, &len)) != 0 ||
|
|
(r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0)
|
|
goto out;
|
|
if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO)
|
|
fmprintf(stderr, "%s", msg);
|
|
r = 0;
|
|
out:
|
|
free(msg);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
input_userauth_success(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
|
|
if (authctxt == NULL)
|
|
fatal_f("no authentication context");
|
|
free(authctxt->authlist);
|
|
authctxt->authlist = NULL;
|
|
if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
|
|
authctxt->method->cleanup(ssh);
|
|
free(authctxt->methoddata);
|
|
authctxt->methoddata = NULL;
|
|
authctxt->success = 1; /* break out */
|
|
return 0;
|
|
}
|
|
|
|
#if 0
|
|
static int
|
|
input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
|
|
if (authctxt == NULL)
|
|
fatal_f("no authentication context");
|
|
|
|
fatal("Unexpected authentication success during %s.",
|
|
authctxt->method->name);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
char *authlist = NULL;
|
|
u_char partial;
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_userauth_failure: no authentication context");
|
|
|
|
if (sshpkt_get_cstring(ssh, &authlist, NULL) != 0 ||
|
|
sshpkt_get_u8(ssh, &partial) != 0 ||
|
|
sshpkt_get_end(ssh) != 0)
|
|
goto out;
|
|
|
|
if (partial != 0) {
|
|
verbose("Authenticated using \"%s\" with partial success.",
|
|
authctxt->method->name);
|
|
/* reset state */
|
|
pubkey_reset(authctxt);
|
|
}
|
|
debug("Authentications that can continue: %s", authlist);
|
|
|
|
userauth(ssh, authlist);
|
|
authlist = NULL;
|
|
out:
|
|
free(authlist);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Format an identity for logging including filename, key type, fingerprint
|
|
* and location (agent, etc.). Caller must free.
|
|
*/
|
|
static char *
|
|
format_identity(Identity *id)
|
|
{
|
|
char *fp = NULL, *ret = NULL;
|
|
const char *note = "";
|
|
|
|
if (id->key != NULL) {
|
|
fp = sshkey_fingerprint(id->key, options.fingerprint_hash,
|
|
SSH_FP_DEFAULT);
|
|
}
|
|
if (id->key) {
|
|
if ((id->key->flags & SSHKEY_FLAG_EXT) != 0)
|
|
note = " token";
|
|
else if (sshkey_is_sk(id->key))
|
|
note = " authenticator";
|
|
}
|
|
xasprintf(&ret, "%s %s%s%s%s%s%s",
|
|
id->filename,
|
|
id->key ? sshkey_type(id->key) : "", id->key ? " " : "",
|
|
fp ? fp : "",
|
|
id->userprovided ? " explicit" : "", note,
|
|
id->agent_fd != -1 ? " agent" : "");
|
|
free(fp);
|
|
return ret;
|
|
}
|
|
|
|
static int
|
|
input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
struct sshkey *key = NULL;
|
|
Identity *id = NULL;
|
|
int pktype, found = 0, sent = 0;
|
|
size_t blen;
|
|
char *pkalg = NULL, *fp = NULL, *ident = NULL;
|
|
u_char *pkblob = NULL;
|
|
int r;
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_userauth_pk_ok: no authentication context");
|
|
|
|
if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 ||
|
|
(r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 ||
|
|
(r = sshpkt_get_end(ssh)) != 0)
|
|
goto done;
|
|
|
|
if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) {
|
|
debug_f("server sent unknown pkalg %s", pkalg);
|
|
goto done;
|
|
}
|
|
if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) {
|
|
debug_r(r, "no key from blob. pkalg %s", pkalg);
|
|
goto done;
|
|
}
|
|
if (key->type != pktype) {
|
|
error("input_userauth_pk_ok: type mismatch "
|
|
"for decoded key (received %d, expected %d)",
|
|
key->type, pktype);
|
|
goto done;
|
|
}
|
|
|
|
/*
|
|
* search keys in the reverse order, because last candidate has been
|
|
* moved to the end of the queue. this also avoids confusion by
|
|
* duplicate keys
|
|
*/
|
|
TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
|
|
if (sshkey_equal(key, id->key)) {
|
|
found = 1;
|
|
break;
|
|
}
|
|
}
|
|
if (!found || id == NULL) {
|
|
fp = sshkey_fingerprint(key, options.fingerprint_hash,
|
|
SSH_FP_DEFAULT);
|
|
error_f("server replied with unknown key: %s %s",
|
|
sshkey_type(key), fp == NULL ? "<ERROR>" : fp);
|
|
goto done;
|
|
}
|
|
ident = format_identity(id);
|
|
debug("Server accepts key: %s", ident);
|
|
sent = sign_and_send_pubkey(ssh, id);
|
|
r = 0;
|
|
done:
|
|
sshkey_free(key);
|
|
free(ident);
|
|
free(fp);
|
|
free(pkalg);
|
|
free(pkblob);
|
|
|
|
/* try another method if we did not send a packet */
|
|
if (r == 0 && sent == 0)
|
|
userauth(ssh, NULL);
|
|
return r;
|
|
}
|
|
|
|
#ifdef GSSAPI
|
|
static int
|
|
userauth_gssapi(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
Gssctxt *gssctxt = NULL;
|
|
OM_uint32 min;
|
|
int r, ok = 0;
|
|
gss_OID mech = NULL;
|
|
|
|
/* Try one GSSAPI method at a time, rather than sending them all at
|
|
* once. */
|
|
|
|
if (authctxt->gss_supported_mechs == NULL)
|
|
gss_indicate_mechs(&min, &authctxt->gss_supported_mechs);
|
|
|
|
/* Check to see whether the mechanism is usable before we offer it */
|
|
while (authctxt->mech_tried < authctxt->gss_supported_mechs->count &&
|
|
!ok) {
|
|
mech = &authctxt->gss_supported_mechs->
|
|
elements[authctxt->mech_tried];
|
|
/* My DER encoding requires length<128 */
|
|
if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt,
|
|
mech, authctxt->host)) {
|
|
ok = 1; /* Mechanism works */
|
|
} else {
|
|
authctxt->mech_tried++;
|
|
}
|
|
}
|
|
|
|
if (!ok || mech == NULL)
|
|
return 0;
|
|
|
|
authctxt->methoddata=(void *)gssctxt;
|
|
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_u32(ssh, 1)) != 0 ||
|
|
(r = sshpkt_put_u32(ssh, (mech->length) + 2)) != 0 ||
|
|
(r = sshpkt_put_u8(ssh, SSH_GSS_OIDTYPE)) != 0 ||
|
|
(r = sshpkt_put_u8(ssh, mech->length)) != 0 ||
|
|
(r = sshpkt_put(ssh, mech->elements, mech->length)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
|
|
|
|
authctxt->mech_tried++; /* Move along to next candidate */
|
|
|
|
return 1;
|
|
}
|
|
|
|
static void
|
|
userauth_gssapi_cleanup(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
Gssctxt *gssctxt = (Gssctxt *)authctxt->methoddata;
|
|
|
|
ssh_gssapi_delete_ctx(&gssctxt);
|
|
authctxt->methoddata = NULL;
|
|
|
|
free(authctxt->gss_supported_mechs);
|
|
authctxt->gss_supported_mechs = NULL;
|
|
}
|
|
|
|
static OM_uint32
|
|
process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
Gssctxt *gssctxt = authctxt->methoddata;
|
|
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
|
|
gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
|
|
gss_buffer_desc gssbuf;
|
|
OM_uint32 status, ms, flags;
|
|
int r;
|
|
|
|
status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
|
|
recv_tok, &send_tok, &flags);
|
|
|
|
if (send_tok.length > 0) {
|
|
u_char type = GSS_ERROR(status) ?
|
|
SSH2_MSG_USERAUTH_GSSAPI_ERRTOK :
|
|
SSH2_MSG_USERAUTH_GSSAPI_TOKEN;
|
|
|
|
if ((r = sshpkt_start(ssh, type)) != 0 ||
|
|
(r = sshpkt_put_string(ssh, send_tok.value,
|
|
send_tok.length)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send %u packet", type);
|
|
|
|
gss_release_buffer(&ms, &send_tok);
|
|
}
|
|
|
|
if (status == GSS_S_COMPLETE) {
|
|
/* send either complete or MIC, depending on mechanism */
|
|
if (!(flags & GSS_C_INTEG_FLAG)) {
|
|
if ((r = sshpkt_start(ssh,
|
|
SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send completion");
|
|
} else {
|
|
struct sshbuf *b;
|
|
|
|
if ((b = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
ssh_gssapi_buildmic(b, authctxt->server_user,
|
|
authctxt->service, "gssapi-with-mic",
|
|
ssh->kex->session_id);
|
|
|
|
if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
|
|
fatal_f("sshbuf_mutable_ptr failed");
|
|
gssbuf.length = sshbuf_len(b);
|
|
|
|
status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
|
|
|
|
if (!GSS_ERROR(status)) {
|
|
if ((r = sshpkt_start(ssh,
|
|
SSH2_MSG_USERAUTH_GSSAPI_MIC)) != 0 ||
|
|
(r = sshpkt_put_string(ssh, mic.value,
|
|
mic.length)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send MIC");
|
|
}
|
|
|
|
sshbuf_free(b);
|
|
gss_release_buffer(&ms, &mic);
|
|
}
|
|
}
|
|
|
|
return status;
|
|
}
|
|
|
|
static int
|
|
input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
Gssctxt *gssctxt;
|
|
size_t oidlen;
|
|
u_char *oidv = NULL;
|
|
int r;
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_gssapi_response: no authentication context");
|
|
gssctxt = authctxt->methoddata;
|
|
|
|
/* Setup our OID */
|
|
if ((r = sshpkt_get_string(ssh, &oidv, &oidlen)) != 0)
|
|
goto done;
|
|
|
|
if (oidlen <= 2 ||
|
|
oidv[0] != SSH_GSS_OIDTYPE ||
|
|
oidv[1] != oidlen - 2) {
|
|
debug("Badly encoded mechanism OID received");
|
|
userauth(ssh, NULL);
|
|
goto ok;
|
|
}
|
|
|
|
if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
|
|
fatal("Server returned different OID than expected");
|
|
|
|
if ((r = sshpkt_get_end(ssh)) != 0)
|
|
goto done;
|
|
|
|
if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) {
|
|
/* Start again with next method on list */
|
|
debug("Trying to start again");
|
|
userauth(ssh, NULL);
|
|
goto ok;
|
|
}
|
|
ok:
|
|
r = 0;
|
|
done:
|
|
free(oidv);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
gss_buffer_desc recv_tok;
|
|
u_char *p = NULL;
|
|
size_t len;
|
|
OM_uint32 status;
|
|
int r;
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_gssapi_response: no authentication context");
|
|
|
|
if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
|
|
(r = sshpkt_get_end(ssh)) != 0)
|
|
goto out;
|
|
|
|
recv_tok.value = p;
|
|
recv_tok.length = len;
|
|
status = process_gssapi_token(ssh, &recv_tok);
|
|
|
|
/* Start again with the next method in the list */
|
|
if (GSS_ERROR(status)) {
|
|
userauth(ssh, NULL);
|
|
/* ok */
|
|
}
|
|
r = 0;
|
|
out:
|
|
free(p);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
Gssctxt *gssctxt;
|
|
gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
|
|
gss_buffer_desc recv_tok;
|
|
OM_uint32 ms;
|
|
u_char *p = NULL;
|
|
size_t len;
|
|
int r;
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_gssapi_response: no authentication context");
|
|
gssctxt = authctxt->methoddata;
|
|
|
|
if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
|
|
(r = sshpkt_get_end(ssh)) != 0) {
|
|
free(p);
|
|
return r;
|
|
}
|
|
|
|
/* Stick it into GSSAPI and see what it says */
|
|
recv_tok.value = p;
|
|
recv_tok.length = len;
|
|
(void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
|
|
&recv_tok, &send_tok, NULL);
|
|
free(p);
|
|
gss_release_buffer(&ms, &send_tok);
|
|
|
|
/* Server will be returning a failed packet after this one */
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh)
|
|
{
|
|
char *msg = NULL;
|
|
char *lang = NULL;
|
|
int r;
|
|
|
|
if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* maj */
|
|
(r = sshpkt_get_u32(ssh, NULL)) != 0 || /* min */
|
|
(r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 ||
|
|
(r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0)
|
|
goto out;
|
|
r = sshpkt_get_end(ssh);
|
|
debug("Server GSSAPI Error:\n%s", msg);
|
|
out:
|
|
free(msg);
|
|
free(lang);
|
|
return r;
|
|
}
|
|
#endif /* GSSAPI */
|
|
|
|
static int
|
|
userauth_none(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
int r;
|
|
|
|
/* initial userauth request */
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
userauth_passwd(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
char *password, *prompt = NULL;
|
|
const char *host = options.host_key_alias ? options.host_key_alias :
|
|
authctxt->host;
|
|
int r;
|
|
|
|
if (authctxt->attempt_passwd++ >= options.number_of_password_prompts)
|
|
return 0;
|
|
|
|
if (authctxt->attempt_passwd != 1)
|
|
error("Permission denied, please try again.");
|
|
|
|
xasprintf(&prompt, "%s@%s's password: ", authctxt->server_user, host);
|
|
password = read_passphrase(prompt, 0);
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_u8(ssh, 0)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, password)) != 0 ||
|
|
(r = sshpkt_add_padding(ssh, 64)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
|
|
free(prompt);
|
|
if (password != NULL)
|
|
freezero(password, strlen(password));
|
|
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
|
|
&input_userauth_passwd_changereq);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
|
|
*/
|
|
static int
|
|
input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
char *info = NULL, *lang = NULL, *password = NULL, *retype = NULL;
|
|
char prompt[256];
|
|
const char *host;
|
|
int r;
|
|
|
|
debug2("input_userauth_passwd_changereq");
|
|
|
|
if (authctxt == NULL)
|
|
fatal("input_userauth_passwd_changereq: "
|
|
"no authentication context");
|
|
host = options.host_key_alias ? options.host_key_alias : authctxt->host;
|
|
|
|
if ((r = sshpkt_get_cstring(ssh, &info, NULL)) != 0 ||
|
|
(r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0)
|
|
goto out;
|
|
if (strlen(info) > 0)
|
|
logit("%s", info);
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_u8(ssh, 1)) != 0) /* additional info */
|
|
goto out;
|
|
|
|
snprintf(prompt, sizeof(prompt),
|
|
"Enter %.30s@%.128s's old password: ",
|
|
authctxt->server_user, host);
|
|
password = read_passphrase(prompt, 0);
|
|
if ((r = sshpkt_put_cstring(ssh, password)) != 0)
|
|
goto out;
|
|
|
|
freezero(password, strlen(password));
|
|
password = NULL;
|
|
while (password == NULL) {
|
|
snprintf(prompt, sizeof(prompt),
|
|
"Enter %.30s@%.128s's new password: ",
|
|
authctxt->server_user, host);
|
|
password = read_passphrase(prompt, RP_ALLOW_EOF);
|
|
if (password == NULL) {
|
|
/* bail out */
|
|
r = 0;
|
|
goto out;
|
|
}
|
|
snprintf(prompt, sizeof(prompt),
|
|
"Retype %.30s@%.128s's new password: ",
|
|
authctxt->server_user, host);
|
|
retype = read_passphrase(prompt, 0);
|
|
if (strcmp(password, retype) != 0) {
|
|
freezero(password, strlen(password));
|
|
logit("Mismatch; try again, EOF to quit.");
|
|
password = NULL;
|
|
}
|
|
freezero(retype, strlen(retype));
|
|
}
|
|
if ((r = sshpkt_put_cstring(ssh, password)) != 0 ||
|
|
(r = sshpkt_add_padding(ssh, 64)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
goto out;
|
|
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
|
|
&input_userauth_passwd_changereq);
|
|
r = 0;
|
|
out:
|
|
if (password)
|
|
freezero(password, strlen(password));
|
|
free(info);
|
|
free(lang);
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Select an algorithm for publickey signatures.
|
|
* Returns algorithm (caller must free) or NULL if no mutual algorithm found.
|
|
*
|
|
* Call with ssh==NULL to ignore server-sig-algs extension list and
|
|
* only attempt with the key's base signature type.
|
|
*/
|
|
static char *
|
|
key_sig_algorithm(struct ssh *ssh, const struct sshkey *key)
|
|
{
|
|
char *allowed, *oallowed, *cp, *tmp, *alg = NULL;
|
|
const char *server_sig_algs;
|
|
|
|
/*
|
|
* The signature algorithm will only differ from the key algorithm
|
|
* for RSA keys/certs and when the server advertises support for
|
|
* newer (SHA2) algorithms.
|
|
*/
|
|
if (ssh == NULL || ssh->kex->server_sig_algs == NULL ||
|
|
(key->type != KEY_RSA && key->type != KEY_RSA_CERT) ||
|
|
(key->type == KEY_RSA_CERT && (ssh->compat & SSH_BUG_SIGTYPE))) {
|
|
/* Filter base key signature alg against our configuration */
|
|
return match_list(sshkey_ssh_name(key),
|
|
options.pubkey_accepted_algos, NULL);
|
|
}
|
|
|
|
/*
|
|
* Workaround OpenSSH 7.4 bug: this version supports RSA/SHA-2 but
|
|
* fails to advertise it via SSH2_MSG_EXT_INFO.
|
|
*/
|
|
server_sig_algs = ssh->kex->server_sig_algs;
|
|
if (key->type == KEY_RSA && (ssh->compat & SSH_BUG_SIGTYPE74))
|
|
server_sig_algs = "rsa-sha2-256,rsa-sha2-512";
|
|
|
|
/*
|
|
* For RSA keys/certs, since these might have a different sig type:
|
|
* find the first entry in PubkeyAcceptedAlgorithms of the right type
|
|
* that also appears in the supported signature algorithms list from
|
|
* the server.
|
|
*/
|
|
oallowed = allowed = xstrdup(options.pubkey_accepted_algos);
|
|
while ((cp = strsep(&allowed, ",")) != NULL) {
|
|
if (sshkey_type_from_name(cp) != key->type)
|
|
continue;
|
|
tmp = match_list(sshkey_sigalg_by_name(cp),
|
|
server_sig_algs, NULL);
|
|
if (tmp != NULL)
|
|
alg = xstrdup(cp);
|
|
free(tmp);
|
|
if (alg != NULL)
|
|
break;
|
|
}
|
|
free(oallowed);
|
|
return alg;
|
|
}
|
|
|
|
static int
|
|
identity_sign(struct identity *id, u_char **sigp, size_t *lenp,
|
|
const u_char *data, size_t datalen, u_int compat, const char *alg)
|
|
{
|
|
struct sshkey *sign_key = NULL, *prv = NULL;
|
|
int is_agent = 0, retried = 0, r = SSH_ERR_INTERNAL_ERROR;
|
|
struct notifier_ctx *notifier = NULL;
|
|
char *fp = NULL, *pin = NULL, *prompt = NULL;
|
|
|
|
*sigp = NULL;
|
|
*lenp = 0;
|
|
|
|
/* The agent supports this key. */
|
|
if (id->key != NULL && id->agent_fd != -1) {
|
|
return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp,
|
|
data, datalen, alg, compat);
|
|
}
|
|
|
|
/*
|
|
* We have already loaded the private key or the private key is
|
|
* stored in external hardware.
|
|
*/
|
|
if (id->key != NULL &&
|
|
(id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) {
|
|
sign_key = id->key;
|
|
is_agent = 1;
|
|
} else {
|
|
/* Load the private key from the file. */
|
|
if ((prv = load_identity_file(id)) == NULL)
|
|
return SSH_ERR_KEY_NOT_FOUND;
|
|
if (id->key != NULL && !sshkey_equal_public(prv, id->key)) {
|
|
error_f("private key %s contents do not match public",
|
|
id->filename);
|
|
r = SSH_ERR_KEY_NOT_FOUND;
|
|
goto out;
|
|
}
|
|
sign_key = prv;
|
|
}
|
|
retry_pin:
|
|
/* Prompt for touch for non-agent FIDO keys that request UP */
|
|
if (!is_agent && sshkey_is_sk(sign_key) &&
|
|
(sign_key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) {
|
|
/* XXX should batch mode just skip these? */
|
|
if ((fp = sshkey_fingerprint(sign_key,
|
|
options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
|
|
fatal_f("fingerprint failed");
|
|
notifier = notify_start(options.batch_mode,
|
|
"Confirm user presence for key %s %s",
|
|
sshkey_type(sign_key), fp);
|
|
free(fp);
|
|
}
|
|
if ((r = sshkey_sign(sign_key, sigp, lenp, data, datalen,
|
|
alg, options.sk_provider, pin, compat)) != 0) {
|
|
debug_fr(r, "sshkey_sign");
|
|
if (!retried && pin == NULL && !is_agent &&
|
|
sshkey_is_sk(sign_key) &&
|
|
r == SSH_ERR_KEY_WRONG_PASSPHRASE) {
|
|
notify_complete(notifier, NULL);
|
|
notifier = NULL;
|
|
xasprintf(&prompt, "Enter PIN for %s key %s: ",
|
|
sshkey_type(sign_key), id->filename);
|
|
pin = read_passphrase(prompt, 0);
|
|
retried = 1;
|
|
goto retry_pin;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* PKCS#11 tokens may not support all signature algorithms,
|
|
* so check what we get back.
|
|
*/
|
|
if ((r = sshkey_check_sigtype(*sigp, *lenp, alg)) != 0) {
|
|
debug_fr(r, "sshkey_check_sigtype");
|
|
goto out;
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
free(prompt);
|
|
if (pin != NULL)
|
|
freezero(pin, strlen(pin));
|
|
notify_complete(notifier, r == 0 ? "User presence confirmed" : NULL);
|
|
sshkey_free(prv);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
id_filename_matches(Identity *id, Identity *private_id)
|
|
{
|
|
static const char * const suffixes[] = { ".pub", "-cert.pub", NULL };
|
|
size_t len = strlen(id->filename), plen = strlen(private_id->filename);
|
|
size_t i, slen;
|
|
|
|
if (strcmp(id->filename, private_id->filename) == 0)
|
|
return 1;
|
|
for (i = 0; suffixes[i]; i++) {
|
|
slen = strlen(suffixes[i]);
|
|
if (len > slen && plen == len - slen &&
|
|
strcmp(id->filename + (len - slen), suffixes[i]) == 0 &&
|
|
memcmp(id->filename, private_id->filename, plen) == 0)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
sign_and_send_pubkey(struct ssh *ssh, Identity *id)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
struct sshbuf *b = NULL;
|
|
Identity *private_id, *sign_id = NULL;
|
|
u_char *signature = NULL;
|
|
size_t slen = 0, skip = 0;
|
|
int r, fallback_sigtype, sent = 0;
|
|
char *alg = NULL, *fp = NULL;
|
|
const char *loc = "", *method = "publickey";
|
|
int hostbound = 0;
|
|
|
|
/* prefer host-bound pubkey signatures if supported by server */
|
|
if ((ssh->kex->flags & KEX_HAS_PUBKEY_HOSTBOUND) != 0 &&
|
|
(options.pubkey_authentication & SSH_PUBKEY_AUTH_HBOUND) != 0) {
|
|
hostbound = 1;
|
|
method = "publickey-hostbound-v00@openssh.com";
|
|
}
|
|
|
|
if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash,
|
|
SSH_FP_DEFAULT)) == NULL)
|
|
return 0;
|
|
|
|
debug3_f("using %s with %s %s", method, sshkey_type(id->key), fp);
|
|
|
|
/*
|
|
* If the key is an certificate, try to find a matching private key
|
|
* and use it to complete the signature.
|
|
* If no such private key exists, fall back to trying the certificate
|
|
* key itself in case it has a private half already loaded.
|
|
* This will try to set sign_id to the private key that will perform
|
|
* the signature.
|
|
*/
|
|
if (sshkey_is_cert(id->key)) {
|
|
TAILQ_FOREACH(private_id, &authctxt->keys, next) {
|
|
if (sshkey_equal_public(id->key, private_id->key) &&
|
|
id->key->type != private_id->key->type) {
|
|
sign_id = private_id;
|
|
break;
|
|
}
|
|
}
|
|
/*
|
|
* Exact key matches are preferred, but also allow
|
|
* filename matches for non-PKCS#11/agent keys that
|
|
* didn't load public keys. This supports the case
|
|
* of keeping just a private key file and public
|
|
* certificate on disk.
|
|
*/
|
|
if (sign_id == NULL &&
|
|
!id->isprivate && id->agent_fd == -1 &&
|
|
(id->key->flags & SSHKEY_FLAG_EXT) == 0) {
|
|
TAILQ_FOREACH(private_id, &authctxt->keys, next) {
|
|
if (private_id->key == NULL &&
|
|
id_filename_matches(id, private_id)) {
|
|
sign_id = private_id;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (sign_id != NULL) {
|
|
debug2_f("using private key \"%s\"%s for "
|
|
"certificate", sign_id->filename,
|
|
sign_id->agent_fd != -1 ? " from agent" : "");
|
|
} else {
|
|
debug_f("no separate private key for certificate "
|
|
"\"%s\"", id->filename);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If the above didn't select another identity to do the signing
|
|
* then default to the one we started with.
|
|
*/
|
|
if (sign_id == NULL)
|
|
sign_id = id;
|
|
|
|
/* assemble and sign data */
|
|
for (fallback_sigtype = 0; fallback_sigtype <= 1; fallback_sigtype++) {
|
|
free(alg);
|
|
slen = 0;
|
|
signature = NULL;
|
|
if ((alg = key_sig_algorithm(fallback_sigtype ? NULL : ssh,
|
|
id->key)) == NULL) {
|
|
error_f("no mutual signature supported");
|
|
goto out;
|
|
}
|
|
debug3_f("signing using %s %s", alg, fp);
|
|
|
|
sshbuf_free(b);
|
|
if ((b = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
if (ssh->compat & SSH_OLD_SESSIONID) {
|
|
if ((r = sshbuf_putb(b, ssh->kex->session_id)) != 0)
|
|
fatal_fr(r, "sshbuf_putb");
|
|
} else {
|
|
if ((r = sshbuf_put_stringb(b,
|
|
ssh->kex->session_id)) != 0)
|
|
fatal_fr(r, "sshbuf_put_stringb");
|
|
}
|
|
skip = sshbuf_len(b);
|
|
if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, method)) != 0 ||
|
|
(r = sshbuf_put_u8(b, 1)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, alg)) != 0 ||
|
|
(r = sshkey_puts(id->key, b)) != 0) {
|
|
fatal_fr(r, "assemble signed data");
|
|
}
|
|
if (hostbound) {
|
|
if (ssh->kex->initial_hostkey == NULL) {
|
|
fatal_f("internal error: initial hostkey "
|
|
"not recorded");
|
|
}
|
|
if ((r = sshkey_puts(ssh->kex->initial_hostkey, b)) != 0)
|
|
fatal_fr(r, "assemble %s hostkey", method);
|
|
}
|
|
/* generate signature */
|
|
r = identity_sign(sign_id, &signature, &slen,
|
|
sshbuf_ptr(b), sshbuf_len(b), ssh->compat, alg);
|
|
if (r == 0)
|
|
break;
|
|
else if (r == SSH_ERR_KEY_NOT_FOUND)
|
|
goto out; /* soft failure */
|
|
else if (r == SSH_ERR_SIGN_ALG_UNSUPPORTED &&
|
|
!fallback_sigtype) {
|
|
if (sign_id->agent_fd != -1)
|
|
loc = "agent ";
|
|
else if ((sign_id->key->flags & SSHKEY_FLAG_EXT) != 0)
|
|
loc = "token ";
|
|
logit("%skey %s %s returned incorrect signature type",
|
|
loc, sshkey_type(id->key), fp);
|
|
continue;
|
|
}
|
|
error_fr(r, "signing failed for %s \"%s\"%s",
|
|
sshkey_type(sign_id->key), sign_id->filename,
|
|
id->agent_fd != -1 ? " from agent" : "");
|
|
goto out;
|
|
}
|
|
if (slen == 0 || signature == NULL) /* shouldn't happen */
|
|
fatal_f("no signature");
|
|
|
|
/* append signature */
|
|
if ((r = sshbuf_put_string(b, signature, slen)) != 0)
|
|
fatal_fr(r, "append signature");
|
|
|
|
#ifdef DEBUG_PK
|
|
sshbuf_dump(b, stderr);
|
|
#endif
|
|
/* skip session id and packet type */
|
|
if ((r = sshbuf_consume(b, skip + 1)) != 0)
|
|
fatal_fr(r, "consume");
|
|
|
|
/* put remaining data from buffer into packet */
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_putb(ssh, b)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "enqueue request");
|
|
|
|
/* success */
|
|
sent = 1;
|
|
|
|
out:
|
|
free(fp);
|
|
free(alg);
|
|
sshbuf_free(b);
|
|
freezero(signature, slen);
|
|
return sent;
|
|
}
|
|
|
|
static int
|
|
send_pubkey_test(struct ssh *ssh, Identity *id)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
u_char *blob = NULL;
|
|
char *alg = NULL;
|
|
size_t bloblen;
|
|
u_int have_sig = 0;
|
|
int sent = 0, r;
|
|
|
|
if ((alg = key_sig_algorithm(ssh, id->key)) == NULL) {
|
|
debug_f("no mutual signature algorithm");
|
|
goto out;
|
|
}
|
|
|
|
if ((r = sshkey_to_blob(id->key, &blob, &bloblen)) != 0) {
|
|
/* we cannot handle this key */
|
|
debug3_f("cannot handle key");
|
|
goto out;
|
|
}
|
|
/* register callback for USERAUTH_PK_OK message */
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
|
|
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_u8(ssh, have_sig)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, alg)) != 0 ||
|
|
(r = sshpkt_put_string(ssh, blob, bloblen)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
sent = 1;
|
|
|
|
out:
|
|
free(alg);
|
|
free(blob);
|
|
return sent;
|
|
}
|
|
|
|
static struct sshkey *
|
|
load_identity_file(Identity *id)
|
|
{
|
|
struct sshkey *private = NULL;
|
|
char prompt[300], *passphrase, *comment;
|
|
int r, quit = 0, i;
|
|
struct stat st;
|
|
|
|
if (stat(id->filename, &st) == -1) {
|
|
do_log2(id->userprovided ?
|
|
SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_DEBUG3,
|
|
"no such identity: %s: %s", id->filename, strerror(errno));
|
|
return NULL;
|
|
}
|
|
snprintf(prompt, sizeof prompt,
|
|
"Enter passphrase for key '%.100s': ", id->filename);
|
|
for (i = 0; i <= options.number_of_password_prompts; i++) {
|
|
if (i == 0)
|
|
passphrase = "";
|
|
else {
|
|
passphrase = read_passphrase(prompt, 0);
|
|
if (*passphrase == '\0') {
|
|
debug2("no passphrase given, try next key");
|
|
free(passphrase);
|
|
break;
|
|
}
|
|
}
|
|
switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename,
|
|
passphrase, &private, &comment))) {
|
|
case 0:
|
|
break;
|
|
case SSH_ERR_KEY_WRONG_PASSPHRASE:
|
|
if (options.batch_mode) {
|
|
quit = 1;
|
|
break;
|
|
}
|
|
if (i != 0)
|
|
debug2("bad passphrase given, try again...");
|
|
break;
|
|
case SSH_ERR_SYSTEM_ERROR:
|
|
if (errno == ENOENT) {
|
|
debug2_r(r, "Load key \"%s\"", id->filename);
|
|
quit = 1;
|
|
break;
|
|
}
|
|
/* FALLTHROUGH */
|
|
default:
|
|
error_r(r, "Load key \"%s\"", id->filename);
|
|
quit = 1;
|
|
break;
|
|
}
|
|
if (private != NULL && sshkey_is_sk(private) &&
|
|
options.sk_provider == NULL) {
|
|
debug("key \"%s\" is an authenticator-hosted key, "
|
|
"but no provider specified", id->filename);
|
|
sshkey_free(private);
|
|
private = NULL;
|
|
quit = 1;
|
|
}
|
|
if (!quit && (r = sshkey_check_rsa_length(private,
|
|
options.required_rsa_size)) != 0) {
|
|
debug_fr(r, "Skipping key %s", id->filename);
|
|
sshkey_free(private);
|
|
private = NULL;
|
|
quit = 1;
|
|
}
|
|
if (!quit && private != NULL && id->agent_fd == -1 &&
|
|
!(id->key && id->isprivate))
|
|
maybe_add_key_to_agent(id->filename, private, comment,
|
|
passphrase);
|
|
if (i > 0)
|
|
freezero(passphrase, strlen(passphrase));
|
|
free(comment);
|
|
if (private != NULL || quit)
|
|
break;
|
|
}
|
|
return private;
|
|
}
|
|
|
|
static int
|
|
key_type_allowed_by_config(struct sshkey *key)
|
|
{
|
|
if (match_pattern_list(sshkey_ssh_name(key),
|
|
options.pubkey_accepted_algos, 0) == 1)
|
|
return 1;
|
|
|
|
/* RSA keys/certs might be allowed by alternate signature types */
|
|
switch (key->type) {
|
|
case KEY_RSA:
|
|
if (match_pattern_list("rsa-sha2-512",
|
|
options.pubkey_accepted_algos, 0) == 1)
|
|
return 1;
|
|
if (match_pattern_list("rsa-sha2-256",
|
|
options.pubkey_accepted_algos, 0) == 1)
|
|
return 1;
|
|
break;
|
|
case KEY_RSA_CERT:
|
|
if (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com",
|
|
options.pubkey_accepted_algos, 0) == 1)
|
|
return 1;
|
|
if (match_pattern_list("rsa-sha2-256-cert-v01@openssh.com",
|
|
options.pubkey_accepted_algos, 0) == 1)
|
|
return 1;
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* obtain a list of keys from the agent */
|
|
static int
|
|
get_agent_identities(struct ssh *ssh, int *agent_fdp,
|
|
struct ssh_identitylist **idlistp)
|
|
{
|
|
int r, agent_fd;
|
|
struct ssh_identitylist *idlist;
|
|
|
|
if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) {
|
|
if (r != SSH_ERR_AGENT_NOT_PRESENT)
|
|
debug_fr(r, "ssh_get_authentication_socket");
|
|
return r;
|
|
}
|
|
if ((r = ssh_agent_bind_hostkey(agent_fd, ssh->kex->initial_hostkey,
|
|
ssh->kex->session_id, ssh->kex->initial_sig, 0)) == 0)
|
|
debug_f("bound agent to hostkey");
|
|
else
|
|
debug2_fr(r, "ssh_agent_bind_hostkey");
|
|
|
|
if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) {
|
|
debug_fr(r, "ssh_fetch_identitylist");
|
|
close(agent_fd);
|
|
return r;
|
|
}
|
|
/* success */
|
|
*agent_fdp = agent_fd;
|
|
*idlistp = idlist;
|
|
debug_f("agent returned %zu keys", idlist->nkeys);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* try keys in the following order:
|
|
* 1. certificates listed in the config file
|
|
* 2. other input certificates
|
|
* 3. agent keys that are found in the config file
|
|
* 4. other agent keys
|
|
* 5. keys that are only listed in the config file
|
|
*/
|
|
static void
|
|
pubkey_prepare(struct ssh *ssh, Authctxt *authctxt)
|
|
{
|
|
struct identity *id, *id2, *tmp;
|
|
struct idlist agent, files, *preferred;
|
|
struct sshkey *key;
|
|
int agent_fd = -1, i, r, found;
|
|
size_t j;
|
|
struct ssh_identitylist *idlist;
|
|
char *ident;
|
|
|
|
TAILQ_INIT(&agent); /* keys from the agent */
|
|
TAILQ_INIT(&files); /* keys from the config file */
|
|
preferred = &authctxt->keys;
|
|
TAILQ_INIT(preferred); /* preferred order of keys */
|
|
|
|
/* list of keys stored in the filesystem and PKCS#11 */
|
|
for (i = 0; i < options.num_identity_files; i++) {
|
|
key = options.identity_keys[i];
|
|
if (key && key->cert &&
|
|
key->cert->type != SSH2_CERT_TYPE_USER) {
|
|
debug_f("ignoring certificate %s: not a user "
|
|
"certificate", options.identity_files[i]);
|
|
continue;
|
|
}
|
|
if (key && sshkey_is_sk(key) && options.sk_provider == NULL) {
|
|
debug_f("ignoring authenticator-hosted key %s as no "
|
|
"SecurityKeyProvider has been specified",
|
|
options.identity_files[i]);
|
|
continue;
|
|
}
|
|
options.identity_keys[i] = NULL;
|
|
id = xcalloc(1, sizeof(*id));
|
|
id->agent_fd = -1;
|
|
id->key = key;
|
|
id->filename = xstrdup(options.identity_files[i]);
|
|
id->userprovided = options.identity_file_userprovided[i];
|
|
TAILQ_INSERT_TAIL(&files, id, next);
|
|
}
|
|
/* list of certificates specified by user */
|
|
for (i = 0; i < options.num_certificate_files; i++) {
|
|
key = options.certificates[i];
|
|
if (!sshkey_is_cert(key) || key->cert == NULL ||
|
|
key->cert->type != SSH2_CERT_TYPE_USER) {
|
|
debug_f("ignoring certificate %s: not a user "
|
|
"certificate", options.identity_files[i]);
|
|
continue;
|
|
}
|
|
if (key && sshkey_is_sk(key) && options.sk_provider == NULL) {
|
|
debug_f("ignoring authenticator-hosted key "
|
|
"certificate %s as no "
|
|
"SecurityKeyProvider has been specified",
|
|
options.identity_files[i]);
|
|
continue;
|
|
}
|
|
id = xcalloc(1, sizeof(*id));
|
|
id->agent_fd = -1;
|
|
id->key = key;
|
|
id->filename = xstrdup(options.certificate_files[i]);
|
|
id->userprovided = options.certificate_file_userprovided[i];
|
|
TAILQ_INSERT_TAIL(preferred, id, next);
|
|
}
|
|
/* list of keys supported by the agent */
|
|
if ((r = get_agent_identities(ssh, &agent_fd, &idlist)) == 0) {
|
|
for (j = 0; j < idlist->nkeys; j++) {
|
|
if ((r = sshkey_check_rsa_length(idlist->keys[j],
|
|
options.required_rsa_size)) != 0) {
|
|
debug_fr(r, "ignoring %s agent key",
|
|
sshkey_ssh_name(idlist->keys[j]));
|
|
continue;
|
|
}
|
|
found = 0;
|
|
TAILQ_FOREACH(id, &files, next) {
|
|
/*
|
|
* agent keys from the config file are
|
|
* preferred
|
|
*/
|
|
if (sshkey_equal(idlist->keys[j], id->key)) {
|
|
TAILQ_REMOVE(&files, id, next);
|
|
TAILQ_INSERT_TAIL(preferred, id, next);
|
|
id->agent_fd = agent_fd;
|
|
found = 1;
|
|
break;
|
|
}
|
|
}
|
|
if (!found && !options.identities_only) {
|
|
id = xcalloc(1, sizeof(*id));
|
|
/* XXX "steals" key/comment from idlist */
|
|
id->key = idlist->keys[j];
|
|
id->filename = idlist->comments[j];
|
|
idlist->keys[j] = NULL;
|
|
idlist->comments[j] = NULL;
|
|
id->agent_fd = agent_fd;
|
|
TAILQ_INSERT_TAIL(&agent, id, next);
|
|
}
|
|
}
|
|
ssh_free_identitylist(idlist);
|
|
/* append remaining agent keys */
|
|
TAILQ_CONCAT(preferred, &agent, next);
|
|
authctxt->agent_fd = agent_fd;
|
|
}
|
|
/* Prefer PKCS11 keys that are explicitly listed */
|
|
TAILQ_FOREACH_SAFE(id, &files, next, tmp) {
|
|
if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0)
|
|
continue;
|
|
found = 0;
|
|
TAILQ_FOREACH(id2, &files, next) {
|
|
if (id2->key == NULL ||
|
|
(id2->key->flags & SSHKEY_FLAG_EXT) != 0)
|
|
continue;
|
|
if (sshkey_equal(id->key, id2->key)) {
|
|
TAILQ_REMOVE(&files, id, next);
|
|
TAILQ_INSERT_TAIL(preferred, id, next);
|
|
found = 1;
|
|
break;
|
|
}
|
|
}
|
|
/* If IdentitiesOnly set and key not found then don't use it */
|
|
if (!found && options.identities_only) {
|
|
TAILQ_REMOVE(&files, id, next);
|
|
freezero(id, sizeof(*id));
|
|
}
|
|
}
|
|
/* append remaining keys from the config file */
|
|
TAILQ_CONCAT(preferred, &files, next);
|
|
/* finally, filter by PubkeyAcceptedAlgorithms */
|
|
TAILQ_FOREACH_SAFE(id, preferred, next, id2) {
|
|
if (id->key != NULL && !key_type_allowed_by_config(id->key)) {
|
|
debug("Skipping %s key %s - "
|
|
"corresponding algo not in PubkeyAcceptedAlgorithms",
|
|
sshkey_ssh_name(id->key), id->filename);
|
|
TAILQ_REMOVE(preferred, id, next);
|
|
sshkey_free(id->key);
|
|
free(id->filename);
|
|
memset(id, 0, sizeof(*id));
|
|
continue;
|
|
}
|
|
}
|
|
/* List the keys we plan on using */
|
|
TAILQ_FOREACH_SAFE(id, preferred, next, id2) {
|
|
ident = format_identity(id);
|
|
debug("Will attempt key: %s", ident);
|
|
free(ident);
|
|
}
|
|
debug2_f("done");
|
|
}
|
|
|
|
static void
|
|
pubkey_cleanup(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
Identity *id;
|
|
|
|
if (authctxt->agent_fd != -1) {
|
|
ssh_close_authentication_socket(authctxt->agent_fd);
|
|
authctxt->agent_fd = -1;
|
|
}
|
|
for (id = TAILQ_FIRST(&authctxt->keys); id;
|
|
id = TAILQ_FIRST(&authctxt->keys)) {
|
|
TAILQ_REMOVE(&authctxt->keys, id, next);
|
|
sshkey_free(id->key);
|
|
free(id->filename);
|
|
free(id);
|
|
}
|
|
}
|
|
|
|
static void
|
|
pubkey_reset(Authctxt *authctxt)
|
|
{
|
|
Identity *id;
|
|
|
|
TAILQ_FOREACH(id, &authctxt->keys, next)
|
|
id->tried = 0;
|
|
}
|
|
|
|
static int
|
|
userauth_pubkey(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
Identity *id;
|
|
int sent = 0;
|
|
char *ident;
|
|
|
|
while ((id = TAILQ_FIRST(&authctxt->keys))) {
|
|
if (id->tried++)
|
|
return (0);
|
|
/* move key to the end of the queue */
|
|
TAILQ_REMOVE(&authctxt->keys, id, next);
|
|
TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
|
|
/*
|
|
* send a test message if we have the public key. for
|
|
* encrypted keys we cannot do this and have to load the
|
|
* private key instead
|
|
*/
|
|
if (id->key != NULL) {
|
|
if (id->key != NULL) {
|
|
ident = format_identity(id);
|
|
debug("Offering public key: %s", ident);
|
|
free(ident);
|
|
sent = send_pubkey_test(ssh, id);
|
|
}
|
|
} else {
|
|
debug("Trying private key: %s", id->filename);
|
|
id->key = load_identity_file(id);
|
|
if (id->key != NULL) {
|
|
if (id->key != NULL) {
|
|
id->isprivate = 1;
|
|
sent = sign_and_send_pubkey(ssh, id);
|
|
}
|
|
sshkey_free(id->key);
|
|
id->key = NULL;
|
|
id->isprivate = 0;
|
|
}
|
|
}
|
|
if (sent)
|
|
return (sent);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Send userauth request message specifying keyboard-interactive method.
|
|
*/
|
|
static int
|
|
userauth_kbdint(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
int r;
|
|
|
|
if (authctxt->attempt_kbdint++ >= options.number_of_password_prompts)
|
|
return 0;
|
|
/* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
|
|
if (authctxt->attempt_kbdint > 1 && !authctxt->info_req_seen) {
|
|
debug3("userauth_kbdint: disable: no info_req_seen");
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
|
|
return 0;
|
|
}
|
|
|
|
debug2("userauth_kbdint");
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, "")) != 0 || /* lang */
|
|
(r = sshpkt_put_cstring(ssh, options.kbd_interactive_devices ?
|
|
options.kbd_interactive_devices : "")) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0)
|
|
fatal_fr(r, "send packet");
|
|
|
|
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* parse INFO_REQUEST, prompt user and send INFO_RESPONSE
|
|
*/
|
|
static int
|
|
input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = ssh->authctxt;
|
|
char *name = NULL, *inst = NULL, *lang = NULL, *prompt = NULL;
|
|
char *display_prompt = NULL, *response = NULL;
|
|
u_char echo = 0;
|
|
u_int num_prompts, i;
|
|
int r;
|
|
|
|
debug2_f("entering");
|
|
|
|
if (authctxt == NULL)
|
|
fatal_f("no authentication context");
|
|
|
|
authctxt->info_req_seen = 1;
|
|
|
|
if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 ||
|
|
(r = sshpkt_get_cstring(ssh, &inst, NULL)) != 0 ||
|
|
(r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0)
|
|
goto out;
|
|
if (strlen(name) > 0)
|
|
logit("%s", name);
|
|
if (strlen(inst) > 0)
|
|
logit("%s", inst);
|
|
|
|
if ((r = sshpkt_get_u32(ssh, &num_prompts)) != 0)
|
|
goto out;
|
|
/*
|
|
* Begin to build info response packet based on prompts requested.
|
|
* We commit to providing the correct number of responses, so if
|
|
* further on we run into a problem that prevents this, we have to
|
|
* be sure and clean this up and send a correct error response.
|
|
*/
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE)) != 0 ||
|
|
(r = sshpkt_put_u32(ssh, num_prompts)) != 0)
|
|
goto out;
|
|
|
|
debug2_f("num_prompts %d", num_prompts);
|
|
for (i = 0; i < num_prompts; i++) {
|
|
if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 ||
|
|
(r = sshpkt_get_u8(ssh, &echo)) != 0)
|
|
goto out;
|
|
if (asmprintf(&display_prompt, INT_MAX, NULL, "(%s@%s) %s",
|
|
authctxt->server_user, options.host_key_alias ?
|
|
options.host_key_alias : authctxt->host, prompt) == -1)
|
|
fatal_f("asmprintf failed");
|
|
response = read_passphrase(display_prompt, echo ? RP_ECHO : 0);
|
|
if ((r = sshpkt_put_cstring(ssh, response)) != 0)
|
|
goto out;
|
|
freezero(response, strlen(response));
|
|
free(prompt);
|
|
free(display_prompt);
|
|
display_prompt = response = prompt = NULL;
|
|
}
|
|
/* done with parsing incoming message. */
|
|
if ((r = sshpkt_get_end(ssh)) != 0 ||
|
|
(r = sshpkt_add_padding(ssh, 64)) != 0)
|
|
goto out;
|
|
r = sshpkt_send(ssh);
|
|
out:
|
|
if (response)
|
|
freezero(response, strlen(response));
|
|
free(prompt);
|
|
free(display_prompt);
|
|
free(name);
|
|
free(inst);
|
|
free(lang);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
ssh_keysign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp,
|
|
const u_char *data, size_t datalen)
|
|
{
|
|
struct sshbuf *b;
|
|
struct stat st;
|
|
pid_t pid;
|
|
int r, to[2], from[2], status;
|
|
int sock = ssh_packet_get_connection_in(ssh);
|
|
u_char rversion = 0, version = 2;
|
|
void (*osigchld)(int);
|
|
|
|
*sigp = NULL;
|
|
*lenp = 0;
|
|
|
|
if (stat(_PATH_SSH_KEY_SIGN, &st) == -1) {
|
|
error_f("not installed: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if (fflush(stdout) != 0) {
|
|
error_f("fflush: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if (pipe(to) == -1) {
|
|
error_f("pipe: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if (pipe(from) == -1) {
|
|
error_f("pipe: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if ((pid = fork()) == -1) {
|
|
error_f("fork: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
osigchld = ssh_signal(SIGCHLD, SIG_DFL);
|
|
if (pid == 0) {
|
|
close(from[0]);
|
|
if (dup2(from[1], STDOUT_FILENO) == -1)
|
|
fatal_f("dup2: %s", strerror(errno));
|
|
close(to[1]);
|
|
if (dup2(to[0], STDIN_FILENO) == -1)
|
|
fatal_f("dup2: %s", strerror(errno));
|
|
close(from[1]);
|
|
close(to[0]);
|
|
|
|
if (dup2(sock, STDERR_FILENO + 1) == -1)
|
|
fatal_f("dup2: %s", strerror(errno));
|
|
sock = STDERR_FILENO + 1;
|
|
if (fcntl(sock, F_SETFD, 0) == -1) /* keep the socket on exec */
|
|
debug3_f("fcntl F_SETFD: %s", strerror(errno));
|
|
closefrom(sock + 1);
|
|
|
|
debug3_f("[child] pid=%ld, exec %s",
|
|
(long)getpid(), _PATH_SSH_KEY_SIGN);
|
|
execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL);
|
|
fatal_f("exec(%s): %s", _PATH_SSH_KEY_SIGN,
|
|
strerror(errno));
|
|
}
|
|
close(from[1]);
|
|
close(to[0]);
|
|
sock = STDERR_FILENO + 1;
|
|
|
|
if ((b = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
/* send # of sock, data to be signed */
|
|
if ((r = sshbuf_put_u32(b, sock)) != 0 ||
|
|
(r = sshbuf_put_string(b, data, datalen)) != 0)
|
|
fatal_fr(r, "buffer error");
|
|
if (ssh_msg_send(to[1], version, b) == -1)
|
|
fatal_f("couldn't send request");
|
|
sshbuf_reset(b);
|
|
r = ssh_msg_recv(from[0], b);
|
|
close(from[0]);
|
|
close(to[1]);
|
|
if (r < 0) {
|
|
error_f("no reply");
|
|
goto fail;
|
|
}
|
|
|
|
errno = 0;
|
|
while (waitpid(pid, &status, 0) == -1) {
|
|
if (errno != EINTR) {
|
|
error_f("waitpid %ld: %s", (long)pid, strerror(errno));
|
|
goto fail;
|
|
}
|
|
}
|
|
if (!WIFEXITED(status)) {
|
|
error_f("exited abnormally");
|
|
goto fail;
|
|
}
|
|
if (WEXITSTATUS(status) != 0) {
|
|
error_f("exited with status %d", WEXITSTATUS(status));
|
|
goto fail;
|
|
}
|
|
if ((r = sshbuf_get_u8(b, &rversion)) != 0) {
|
|
error_fr(r, "buffer error");
|
|
goto fail;
|
|
}
|
|
if (rversion != version) {
|
|
error_f("bad version");
|
|
goto fail;
|
|
}
|
|
if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) {
|
|
error_fr(r, "buffer error");
|
|
fail:
|
|
ssh_signal(SIGCHLD, osigchld);
|
|
sshbuf_free(b);
|
|
return -1;
|
|
}
|
|
ssh_signal(SIGCHLD, osigchld);
|
|
sshbuf_free(b);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
userauth_hostbased(struct ssh *ssh)
|
|
{
|
|
Authctxt *authctxt = (Authctxt *)ssh->authctxt;
|
|
struct sshkey *private = NULL;
|
|
struct sshbuf *b = NULL;
|
|
u_char *sig = NULL, *keyblob = NULL;
|
|
char *fp = NULL, *chost = NULL, *lname = NULL;
|
|
size_t siglen = 0, keylen = 0;
|
|
int i, r, success = 0;
|
|
|
|
if (authctxt->ktypes == NULL) {
|
|
authctxt->oktypes = xstrdup(options.hostbased_accepted_algos);
|
|
authctxt->ktypes = authctxt->oktypes;
|
|
}
|
|
|
|
/*
|
|
* Work through each listed type pattern in HostbasedAcceptedAlgorithms,
|
|
* trying each hostkey that matches the type in turn.
|
|
*/
|
|
for (;;) {
|
|
if (authctxt->active_ktype == NULL)
|
|
authctxt->active_ktype = strsep(&authctxt->ktypes, ",");
|
|
if (authctxt->active_ktype == NULL ||
|
|
*authctxt->active_ktype == '\0')
|
|
break;
|
|
debug3_f("trying key type %s", authctxt->active_ktype);
|
|
|
|
/* check for a useful key */
|
|
private = NULL;
|
|
for (i = 0; i < authctxt->sensitive->nkeys; i++) {
|
|
if (authctxt->sensitive->keys[i] == NULL ||
|
|
authctxt->sensitive->keys[i]->type == KEY_UNSPEC)
|
|
continue;
|
|
if (!sshkey_match_keyname_to_sigalgs(
|
|
sshkey_ssh_name(authctxt->sensitive->keys[i]),
|
|
authctxt->active_ktype))
|
|
continue;
|
|
/* we take and free the key */
|
|
private = authctxt->sensitive->keys[i];
|
|
authctxt->sensitive->keys[i] = NULL;
|
|
break;
|
|
}
|
|
/* Found one */
|
|
if (private != NULL)
|
|
break;
|
|
/* No more keys of this type; advance */
|
|
authctxt->active_ktype = NULL;
|
|
}
|
|
if (private == NULL) {
|
|
free(authctxt->oktypes);
|
|
authctxt->oktypes = authctxt->ktypes = NULL;
|
|
authctxt->active_ktype = NULL;
|
|
debug("No more client hostkeys for hostbased authentication.");
|
|
goto out;
|
|
}
|
|
|
|
if ((fp = sshkey_fingerprint(private, options.fingerprint_hash,
|
|
SSH_FP_DEFAULT)) == NULL) {
|
|
error_f("sshkey_fingerprint failed");
|
|
goto out;
|
|
}
|
|
debug_f("trying hostkey %s %s using sigalg %s",
|
|
sshkey_ssh_name(private), fp, authctxt->active_ktype);
|
|
|
|
/* figure out a name for the client host */
|
|
lname = get_local_name(ssh_packet_get_connection_in(ssh));
|
|
if (lname == NULL) {
|
|
error_f("cannot get local ipaddr/name");
|
|
goto out;
|
|
}
|
|
|
|
/* XXX sshbuf_put_stringf? */
|
|
xasprintf(&chost, "%s.", lname);
|
|
debug2_f("chost %s", chost);
|
|
|
|
/* construct data */
|
|
if ((b = sshbuf_new()) == NULL) {
|
|
error_f("sshbuf_new failed");
|
|
goto out;
|
|
}
|
|
if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) {
|
|
error_fr(r, "sshkey_to_blob");
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_put_stringb(b, ssh->kex->session_id)) != 0 ||
|
|
(r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->service)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->active_ktype)) != 0 ||
|
|
(r = sshbuf_put_string(b, keyblob, keylen)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, chost)) != 0 ||
|
|
(r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) {
|
|
error_fr(r, "buffer error");
|
|
goto out;
|
|
}
|
|
|
|
#ifdef DEBUG_PK
|
|
sshbuf_dump(b, stderr);
|
|
#endif
|
|
if ((r = ssh_keysign(ssh, private, &sig, &siglen,
|
|
sshbuf_ptr(b), sshbuf_len(b))) != 0) {
|
|
error("sign using hostkey %s %s failed",
|
|
sshkey_ssh_name(private), fp);
|
|
goto out;
|
|
}
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->active_ktype)) != 0 ||
|
|
(r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, chost)) != 0 ||
|
|
(r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 ||
|
|
(r = sshpkt_put_string(ssh, sig, siglen)) != 0 ||
|
|
(r = sshpkt_send(ssh)) != 0) {
|
|
error_fr(r, "packet error");
|
|
goto out;
|
|
}
|
|
success = 1;
|
|
|
|
out:
|
|
if (sig != NULL)
|
|
freezero(sig, siglen);
|
|
free(keyblob);
|
|
free(lname);
|
|
free(fp);
|
|
free(chost);
|
|
sshkey_free(private);
|
|
sshbuf_free(b);
|
|
|
|
return success;
|
|
}
|
|
|
|
/* find auth method */
|
|
|
|
/*
|
|
* given auth method name, if configurable options permit this method fill
|
|
* in auth_ident field and return true, otherwise return false.
|
|
*/
|
|
static int
|
|
authmethod_is_enabled(Authmethod *method)
|
|
{
|
|
if (method == NULL)
|
|
return 0;
|
|
/* return false if options indicate this method is disabled */
|
|
if (method->enabled == NULL || *method->enabled == 0)
|
|
return 0;
|
|
/* return false if batch mode is enabled but method needs interactive mode */
|
|
if (method->batch_flag != NULL && *method->batch_flag != 0)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static Authmethod *
|
|
authmethod_lookup(const char *name)
|
|
{
|
|
Authmethod *method = NULL;
|
|
if (name != NULL)
|
|
for (method = authmethods; method->name != NULL; method++)
|
|
if (strcmp(name, method->name) == 0)
|
|
return method;
|
|
debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
|
|
return NULL;
|
|
}
|
|
|
|
/* XXX internal state */
|
|
static Authmethod *current = NULL;
|
|
static char *supported = NULL;
|
|
static char *preferred = NULL;
|
|
|
|
/*
|
|
* Given the authentication method list sent by the server, return the
|
|
* next method we should try. If the server initially sends a nil list,
|
|
* use a built-in default list.
|
|
*/
|
|
static Authmethod *
|
|
authmethod_get(char *authlist)
|
|
{
|
|
char *name = NULL;
|
|
u_int next;
|
|
|
|
/* Use a suitable default if we're passed a nil list. */
|
|
if (authlist == NULL || strlen(authlist) == 0)
|
|
authlist = options.preferred_authentications;
|
|
|
|
if (supported == NULL || strcmp(authlist, supported) != 0) {
|
|
debug3("start over, passed a different list %s", authlist);
|
|
free(supported);
|
|
supported = xstrdup(authlist);
|
|
preferred = options.preferred_authentications;
|
|
debug3("preferred %s", preferred);
|
|
current = NULL;
|
|
} else if (current != NULL && authmethod_is_enabled(current))
|
|
return current;
|
|
|
|
for (;;) {
|
|
if ((name = match_list(preferred, supported, &next)) == NULL) {
|
|
debug("No more authentication methods to try.");
|
|
current = NULL;
|
|
return NULL;
|
|
}
|
|
preferred += next;
|
|
debug3("authmethod_lookup %s", name);
|
|
debug3("remaining preferred: %s", preferred);
|
|
if ((current = authmethod_lookup(name)) != NULL &&
|
|
authmethod_is_enabled(current)) {
|
|
debug3("authmethod_is_enabled %s", name);
|
|
debug("Next authentication method: %s", name);
|
|
free(name);
|
|
return current;
|
|
}
|
|
free(name);
|
|
}
|
|
}
|
|
|
|
static char *
|
|
authmethods_get(void)
|
|
{
|
|
Authmethod *method = NULL;
|
|
struct sshbuf *b;
|
|
char *list;
|
|
int r;
|
|
|
|
if ((b = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
for (method = authmethods; method->name != NULL; method++) {
|
|
if (authmethod_is_enabled(method)) {
|
|
if ((r = sshbuf_putf(b, "%s%s",
|
|
sshbuf_len(b) ? "," : "", method->name)) != 0)
|
|
fatal_fr(r, "buffer error");
|
|
}
|
|
}
|
|
if ((list = sshbuf_dup_string(b)) == NULL)
|
|
fatal_f("sshbuf_dup_string failed");
|
|
sshbuf_free(b);
|
|
return list;
|
|
}
|