Fixes: 19261079b7
("openssh: update to OpenSSH v8.7p1")
Sponsored by: The FreeBSD Foundation
820 lines
22 KiB
C
820 lines
22 KiB
C
/* $OpenBSD: auth2.c,v 1.161 2021/04/03 06:18:40 djm Exp $ */
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/*
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* Copyright (c) 2000 Markus Friedl. 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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__RCSID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/uio.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <pwd.h>
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#include <stdarg.h>
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#include <string.h>
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#include <unistd.h>
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#include <time.h>
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#include "stdlib.h"
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#include "atomicio.h"
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#include "xmalloc.h"
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#include "ssh2.h"
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#include "packet.h"
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#include "log.h"
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#include "sshbuf.h"
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#include "misc.h"
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#include "servconf.h"
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#include "compat.h"
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#include "sshkey.h"
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#include "hostfile.h"
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#include "auth.h"
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#include "dispatch.h"
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#include "pathnames.h"
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#include "ssherr.h"
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#include "blacklist_client.h"
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#ifdef GSSAPI
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#include "ssh-gss.h"
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#endif
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#include "monitor_wrap.h"
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#include "digest.h"
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/* import */
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extern ServerOptions options;
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extern struct sshbuf *loginmsg;
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/* methods */
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extern Authmethod method_none;
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extern Authmethod method_pubkey;
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extern Authmethod method_passwd;
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extern Authmethod method_kbdint;
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extern Authmethod method_hostbased;
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#ifdef GSSAPI
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extern Authmethod method_gssapi;
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#endif
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Authmethod *authmethods[] = {
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&method_none,
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&method_pubkey,
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#ifdef GSSAPI
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&method_gssapi,
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#endif
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&method_passwd,
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&method_kbdint,
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&method_hostbased,
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NULL
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};
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/* protocol */
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static int input_service_request(int, u_int32_t, struct ssh *);
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static int input_userauth_request(int, u_int32_t, struct ssh *);
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/* helper */
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static Authmethod *authmethod_lookup(Authctxt *, const char *);
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static char *authmethods_get(Authctxt *authctxt);
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#define MATCH_NONE 0 /* method or submethod mismatch */
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#define MATCH_METHOD 1 /* method matches (no submethod specified) */
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#define MATCH_BOTH 2 /* method and submethod match */
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#define MATCH_PARTIAL 3 /* method matches, submethod can't be checked */
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static int list_starts_with(const char *, const char *, const char *);
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char *
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auth2_read_banner(void)
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{
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struct stat st;
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char *banner = NULL;
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size_t len, n;
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int fd;
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if ((fd = open(options.banner, O_RDONLY)) == -1)
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return (NULL);
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if (fstat(fd, &st) == -1) {
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close(fd);
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return (NULL);
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}
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if (st.st_size <= 0 || st.st_size > 1*1024*1024) {
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close(fd);
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return (NULL);
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}
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len = (size_t)st.st_size; /* truncate */
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banner = xmalloc(len + 1);
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n = atomicio(read, fd, banner, len);
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close(fd);
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if (n != len) {
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free(banner);
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return (NULL);
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}
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banner[n] = '\0';
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return (banner);
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}
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static void
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userauth_send_banner(struct ssh *ssh, const char *msg)
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{
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int r;
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if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_BANNER)) != 0 ||
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(r = sshpkt_put_cstring(ssh, msg)) != 0 ||
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(r = sshpkt_put_cstring(ssh, "")) != 0 || /* language, unused */
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(r = sshpkt_send(ssh)) != 0)
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fatal_fr(r, "send packet");
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debug("%s: sent", __func__);
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}
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static void
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userauth_banner(struct ssh *ssh)
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{
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char *banner = NULL;
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if (options.banner == NULL)
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return;
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if ((banner = PRIVSEP(auth2_read_banner())) == NULL)
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goto done;
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userauth_send_banner(ssh, banner);
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done:
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free(banner);
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}
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/*
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* loop until authctxt->success == TRUE
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*/
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void
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do_authentication2(struct ssh *ssh)
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{
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Authctxt *authctxt = ssh->authctxt;
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ssh_dispatch_init(ssh, &dispatch_protocol_error);
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ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_REQUEST, &input_service_request);
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ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt->success);
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ssh->authctxt = NULL;
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}
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/*ARGSUSED*/
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static int
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input_service_request(int type, u_int32_t seq, struct ssh *ssh)
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{
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Authctxt *authctxt = ssh->authctxt;
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char *service = NULL;
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int r, acceptit = 0;
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if ((r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
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(r = sshpkt_get_end(ssh)) != 0)
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goto out;
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if (authctxt == NULL)
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fatal("input_service_request: no authctxt");
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if (strcmp(service, "ssh-userauth") == 0) {
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if (!authctxt->success) {
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acceptit = 1;
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/* now we can handle user-auth requests */
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ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST,
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&input_userauth_request);
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}
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}
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/* XXX all other service requests are denied */
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if (acceptit) {
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if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_ACCEPT)) != 0 ||
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(r = sshpkt_put_cstring(ssh, service)) != 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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goto out;
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} else {
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debug("bad service request %s", service);
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ssh_packet_disconnect(ssh, "bad service request %s", service);
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}
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r = 0;
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out:
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free(service);
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return r;
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}
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#define MIN_FAIL_DELAY_SECONDS 0.005
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static double
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user_specific_delay(const char *user)
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{
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char b[512];
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size_t len = ssh_digest_bytes(SSH_DIGEST_SHA512);
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u_char *hash = xmalloc(len);
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double delay;
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(void)snprintf(b, sizeof b, "%llu%s",
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(unsigned long long)options.timing_secret, user);
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if (ssh_digest_memory(SSH_DIGEST_SHA512, b, strlen(b), hash, len) != 0)
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fatal_f("ssh_digest_memory");
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/* 0-4.2 ms of delay */
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delay = (double)PEEK_U32(hash) / 1000 / 1000 / 1000 / 1000;
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freezero(hash, len);
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debug3_f("user specific delay %0.3lfms", delay/1000);
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return MIN_FAIL_DELAY_SECONDS + delay;
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}
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static void
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ensure_minimum_time_since(double start, double seconds)
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{
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struct timespec ts;
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double elapsed = monotime_double() - start, req = seconds, remain;
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/* if we've already passed the requested time, scale up */
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while ((remain = seconds - elapsed) < 0.0)
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seconds *= 2;
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ts.tv_sec = remain;
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ts.tv_nsec = (remain - ts.tv_sec) * 1000000000;
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debug3_f("elapsed %0.3lfms, delaying %0.3lfms (requested %0.3lfms)",
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elapsed*1000, remain*1000, req*1000);
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nanosleep(&ts, NULL);
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}
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/*ARGSUSED*/
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static int
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input_userauth_request(int type, u_int32_t seq, struct ssh *ssh)
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{
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Authctxt *authctxt = ssh->authctxt;
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Authmethod *m = NULL;
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char *user = NULL, *service = NULL, *method = NULL, *style = NULL;
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int r, authenticated = 0;
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double tstart = monotime_double();
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if (authctxt == NULL)
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fatal("input_userauth_request: no authctxt");
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if ((r = sshpkt_get_cstring(ssh, &user, NULL)) != 0 ||
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(r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
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(r = sshpkt_get_cstring(ssh, &method, NULL)) != 0)
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goto out;
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debug("userauth-request for user %s service %s method %s", user, service, method);
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debug("attempt %d failures %d", authctxt->attempt, authctxt->failures);
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if ((style = strchr(user, ':')) != NULL)
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*style++ = 0;
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if (authctxt->attempt++ == 0) {
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/* setup auth context */
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authctxt->pw = PRIVSEP(getpwnamallow(ssh, user));
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authctxt->user = xstrdup(user);
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if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
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authctxt->valid = 1;
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debug2_f("setting up authctxt for %s", user);
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} else {
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/* Invalid user, fake password information */
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authctxt->pw = fakepw();
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#ifdef SSH_AUDIT_EVENTS
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PRIVSEP(audit_event(ssh, SSH_INVALID_USER));
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#endif
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}
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#ifdef USE_PAM
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if (options.use_pam)
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PRIVSEP(start_pam(ssh));
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#endif
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ssh_packet_set_log_preamble(ssh, "%suser %s",
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authctxt->valid ? "authenticating " : "invalid ", user);
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setproctitle("%s%s", authctxt->valid ? user : "unknown",
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use_privsep ? " [net]" : "");
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authctxt->service = xstrdup(service);
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authctxt->style = style ? xstrdup(style) : NULL;
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if (use_privsep)
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mm_inform_authserv(service, style);
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userauth_banner(ssh);
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if (auth2_setup_methods_lists(authctxt) != 0)
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ssh_packet_disconnect(ssh,
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"no authentication methods enabled");
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} else if (strcmp(user, authctxt->user) != 0 ||
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strcmp(service, authctxt->service) != 0) {
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ssh_packet_disconnect(ssh, "Change of username or service "
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"not allowed: (%s,%s) -> (%s,%s)",
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authctxt->user, authctxt->service, user, service);
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}
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/* reset state */
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auth2_challenge_stop(ssh);
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#ifdef GSSAPI
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/* XXX move to auth2_gssapi_stop() */
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ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
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ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
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#endif
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auth2_authctxt_reset_info(authctxt);
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authctxt->postponed = 0;
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authctxt->server_caused_failure = 0;
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/* try to authenticate user */
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m = authmethod_lookup(authctxt, method);
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if (m != NULL && authctxt->failures < options.max_authtries) {
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debug2("input_userauth_request: try method %s", method);
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authenticated = m->userauth(ssh);
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}
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if (!authctxt->authenticated)
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ensure_minimum_time_since(tstart,
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user_specific_delay(authctxt->user));
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userauth_finish(ssh, authenticated, method, NULL);
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r = 0;
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out:
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free(service);
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free(user);
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free(method);
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return r;
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}
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void
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userauth_finish(struct ssh *ssh, int authenticated, const char *method,
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const char *submethod)
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{
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Authctxt *authctxt = ssh->authctxt;
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char *methods;
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int r, partial = 0;
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if (!authctxt->valid && authenticated)
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fatal("INTERNAL ERROR: authenticated invalid user %s",
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authctxt->user);
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if (authenticated && authctxt->postponed)
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fatal("INTERNAL ERROR: authenticated and postponed");
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/* Special handling for root */
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if (authenticated && authctxt->pw->pw_uid == 0 &&
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!auth_root_allowed(ssh, method)) {
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authenticated = 0;
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#ifdef SSH_AUDIT_EVENTS
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PRIVSEP(audit_event(ssh, SSH_LOGIN_ROOT_DENIED));
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#endif
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}
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if (authenticated && options.num_auth_methods != 0) {
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if (!auth2_update_methods_lists(authctxt, method, submethod)) {
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authenticated = 0;
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partial = 1;
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}
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}
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/* Log before sending the reply */
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auth_log(ssh, authenticated, partial, method, submethod);
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/* Update information exposed to session */
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if (authenticated || partial)
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auth2_update_session_info(authctxt, method, submethod);
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if (authctxt->postponed)
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return;
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#ifdef USE_PAM
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if (options.use_pam && authenticated) {
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int r, success = PRIVSEP(do_pam_account());
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/* If PAM returned a message, send it to the user. */
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if (sshbuf_len(loginmsg) > 0) {
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if ((r = sshbuf_put(loginmsg, "\0", 1)) != 0)
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fatal("%s: buffer error: %s",
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__func__, ssh_err(r));
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userauth_send_banner(ssh, sshbuf_ptr(loginmsg));
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if ((r = ssh_packet_write_wait(ssh)) != 0) {
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sshpkt_fatal(ssh, r,
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"%s: send PAM banner", __func__);
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}
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}
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if (!success) {
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fatal("Access denied for user %s by PAM account "
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"configuration", authctxt->user);
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}
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}
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#endif
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if (authenticated == 1) {
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/* turn off userauth */
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ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST,
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&dispatch_protocol_ignore);
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if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_SUCCESS)) != 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 success packet");
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/* now we can break out */
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authctxt->success = 1;
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ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user);
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} else {
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/* Allow initial try of "none" auth without failure penalty */
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if (!partial && !authctxt->server_caused_failure &&
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(authctxt->attempt > 1 || strcmp(method, "none") != 0)) {
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authctxt->failures++;
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BLACKLIST_NOTIFY(ssh, BLACKLIST_AUTH_FAIL, "ssh");
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}
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if (authctxt->failures >= options.max_authtries) {
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#ifdef SSH_AUDIT_EVENTS
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PRIVSEP(audit_event(ssh, SSH_LOGIN_EXCEED_MAXTRIES));
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#endif
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auth_maxtries_exceeded(ssh);
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}
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methods = authmethods_get(authctxt);
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debug3_f("failure partial=%d next methods=\"%s\"",
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partial, methods);
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if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_FAILURE)) != 0 ||
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(r = sshpkt_put_cstring(ssh, methods)) != 0 ||
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(r = sshpkt_put_u8(ssh, partial)) != 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 failure packet");
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free(methods);
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}
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}
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/*
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* Checks whether method is allowed by at least one AuthenticationMethods
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* methods list. Returns 1 if allowed, or no methods lists configured.
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* 0 otherwise.
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*/
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int
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auth2_method_allowed(Authctxt *authctxt, const char *method,
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const char *submethod)
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{
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u_int i;
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/*
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* NB. authctxt->num_auth_methods might be zero as a result of
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* auth2_setup_methods_lists(), so check the configuration.
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*/
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if (options.num_auth_methods == 0)
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return 1;
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for (i = 0; i < authctxt->num_auth_methods; i++) {
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if (list_starts_with(authctxt->auth_methods[i], method,
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submethod) != MATCH_NONE)
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return 1;
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}
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return 0;
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}
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static char *
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authmethods_get(Authctxt *authctxt)
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{
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struct sshbuf *b;
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char *list;
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int i, r;
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if ((b = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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for (i = 0; authmethods[i] != NULL; i++) {
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if (strcmp(authmethods[i]->name, "none") == 0)
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continue;
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if (authmethods[i]->enabled == NULL ||
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*(authmethods[i]->enabled) == 0)
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continue;
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if (!auth2_method_allowed(authctxt, authmethods[i]->name,
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NULL))
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continue;
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if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) ? "," : "",
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authmethods[i]->name)) != 0)
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fatal_fr(r, "buffer error");
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}
|
|
if ((list = sshbuf_dup_string(b)) == NULL)
|
|
fatal_f("sshbuf_dup_string failed");
|
|
sshbuf_free(b);
|
|
return list;
|
|
}
|
|
|
|
static Authmethod *
|
|
authmethod_lookup(Authctxt *authctxt, const char *name)
|
|
{
|
|
int i;
|
|
|
|
if (name != NULL)
|
|
for (i = 0; authmethods[i] != NULL; i++)
|
|
if (authmethods[i]->enabled != NULL &&
|
|
*(authmethods[i]->enabled) != 0 &&
|
|
strcmp(name, authmethods[i]->name) == 0 &&
|
|
auth2_method_allowed(authctxt,
|
|
authmethods[i]->name, NULL))
|
|
return authmethods[i];
|
|
debug2("Unrecognized authentication method name: %s",
|
|
name ? name : "NULL");
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Check a comma-separated list of methods for validity. Is need_enable is
|
|
* non-zero, then also require that the methods are enabled.
|
|
* Returns 0 on success or -1 if the methods list is invalid.
|
|
*/
|
|
int
|
|
auth2_methods_valid(const char *_methods, int need_enable)
|
|
{
|
|
char *methods, *omethods, *method, *p;
|
|
u_int i, found;
|
|
int ret = -1;
|
|
|
|
if (*_methods == '\0') {
|
|
error("empty authentication method list");
|
|
return -1;
|
|
}
|
|
omethods = methods = xstrdup(_methods);
|
|
while ((method = strsep(&methods, ",")) != NULL) {
|
|
for (found = i = 0; !found && authmethods[i] != NULL; i++) {
|
|
if ((p = strchr(method, ':')) != NULL)
|
|
*p = '\0';
|
|
if (strcmp(method, authmethods[i]->name) != 0)
|
|
continue;
|
|
if (need_enable) {
|
|
if (authmethods[i]->enabled == NULL ||
|
|
*(authmethods[i]->enabled) == 0) {
|
|
error("Disabled method \"%s\" in "
|
|
"AuthenticationMethods list \"%s\"",
|
|
method, _methods);
|
|
goto out;
|
|
}
|
|
}
|
|
found = 1;
|
|
break;
|
|
}
|
|
if (!found) {
|
|
error("Unknown authentication method \"%s\" in list",
|
|
method);
|
|
goto out;
|
|
}
|
|
}
|
|
ret = 0;
|
|
out:
|
|
free(omethods);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Prune the AuthenticationMethods supplied in the configuration, removing
|
|
* any methods lists that include disabled methods. Note that this might
|
|
* leave authctxt->num_auth_methods == 0, even when multiple required auth
|
|
* has been requested. For this reason, all tests for whether multiple is
|
|
* enabled should consult options.num_auth_methods directly.
|
|
*/
|
|
int
|
|
auth2_setup_methods_lists(Authctxt *authctxt)
|
|
{
|
|
u_int i;
|
|
|
|
/* First, normalise away the "any" pseudo-method */
|
|
if (options.num_auth_methods == 1 &&
|
|
strcmp(options.auth_methods[0], "any") == 0) {
|
|
free(options.auth_methods[0]);
|
|
options.auth_methods[0] = NULL;
|
|
options.num_auth_methods = 0;
|
|
}
|
|
|
|
if (options.num_auth_methods == 0)
|
|
return 0;
|
|
debug3_f("checking methods");
|
|
authctxt->auth_methods = xcalloc(options.num_auth_methods,
|
|
sizeof(*authctxt->auth_methods));
|
|
authctxt->num_auth_methods = 0;
|
|
for (i = 0; i < options.num_auth_methods; i++) {
|
|
if (auth2_methods_valid(options.auth_methods[i], 1) != 0) {
|
|
logit("Authentication methods list \"%s\" contains "
|
|
"disabled method, skipping",
|
|
options.auth_methods[i]);
|
|
continue;
|
|
}
|
|
debug("authentication methods list %d: %s",
|
|
authctxt->num_auth_methods, options.auth_methods[i]);
|
|
authctxt->auth_methods[authctxt->num_auth_methods++] =
|
|
xstrdup(options.auth_methods[i]);
|
|
}
|
|
if (authctxt->num_auth_methods == 0) {
|
|
error("No AuthenticationMethods left after eliminating "
|
|
"disabled methods");
|
|
return -1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
list_starts_with(const char *methods, const char *method,
|
|
const char *submethod)
|
|
{
|
|
size_t l = strlen(method);
|
|
int match;
|
|
const char *p;
|
|
|
|
if (strncmp(methods, method, l) != 0)
|
|
return MATCH_NONE;
|
|
p = methods + l;
|
|
match = MATCH_METHOD;
|
|
if (*p == ':') {
|
|
if (!submethod)
|
|
return MATCH_PARTIAL;
|
|
l = strlen(submethod);
|
|
p += 1;
|
|
if (strncmp(submethod, p, l))
|
|
return MATCH_NONE;
|
|
p += l;
|
|
match = MATCH_BOTH;
|
|
}
|
|
if (*p != ',' && *p != '\0')
|
|
return MATCH_NONE;
|
|
return match;
|
|
}
|
|
|
|
/*
|
|
* Remove method from the start of a comma-separated list of methods.
|
|
* Returns 0 if the list of methods did not start with that method or 1
|
|
* if it did.
|
|
*/
|
|
static int
|
|
remove_method(char **methods, const char *method, const char *submethod)
|
|
{
|
|
char *omethods = *methods, *p;
|
|
size_t l = strlen(method);
|
|
int match;
|
|
|
|
match = list_starts_with(omethods, method, submethod);
|
|
if (match != MATCH_METHOD && match != MATCH_BOTH)
|
|
return 0;
|
|
p = omethods + l;
|
|
if (submethod && match == MATCH_BOTH)
|
|
p += 1 + strlen(submethod); /* include colon */
|
|
if (*p == ',')
|
|
p++;
|
|
*methods = xstrdup(p);
|
|
free(omethods);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Called after successful authentication. Will remove the successful method
|
|
* from the start of each list in which it occurs. If it was the last method
|
|
* in any list, then authentication is deemed successful.
|
|
* Returns 1 if the method completed any authentication list or 0 otherwise.
|
|
*/
|
|
int
|
|
auth2_update_methods_lists(Authctxt *authctxt, const char *method,
|
|
const char *submethod)
|
|
{
|
|
u_int i, found = 0;
|
|
|
|
debug3_f("updating methods list after \"%s\"", method);
|
|
for (i = 0; i < authctxt->num_auth_methods; i++) {
|
|
if (!remove_method(&(authctxt->auth_methods[i]), method,
|
|
submethod))
|
|
continue;
|
|
found = 1;
|
|
if (*authctxt->auth_methods[i] == '\0') {
|
|
debug2("authentication methods list %d complete", i);
|
|
return 1;
|
|
}
|
|
debug3("authentication methods list %d remaining: \"%s\"",
|
|
i, authctxt->auth_methods[i]);
|
|
}
|
|
/* This should not happen, but would be bad if it did */
|
|
if (!found)
|
|
fatal_f("method not in AuthenticationMethods");
|
|
return 0;
|
|
}
|
|
|
|
/* Reset method-specific information */
|
|
void auth2_authctxt_reset_info(Authctxt *authctxt)
|
|
{
|
|
sshkey_free(authctxt->auth_method_key);
|
|
free(authctxt->auth_method_info);
|
|
authctxt->auth_method_key = NULL;
|
|
authctxt->auth_method_info = NULL;
|
|
}
|
|
|
|
/* Record auth method-specific information for logs */
|
|
void
|
|
auth2_record_info(Authctxt *authctxt, const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
int i;
|
|
|
|
free(authctxt->auth_method_info);
|
|
authctxt->auth_method_info = NULL;
|
|
|
|
va_start(ap, fmt);
|
|
i = vasprintf(&authctxt->auth_method_info, fmt, ap);
|
|
va_end(ap);
|
|
|
|
if (i == -1)
|
|
fatal_f("vasprintf failed");
|
|
}
|
|
|
|
/*
|
|
* Records a public key used in authentication. This is used for logging
|
|
* and to ensure that the same key is not subsequently accepted again for
|
|
* multiple authentication.
|
|
*/
|
|
void
|
|
auth2_record_key(Authctxt *authctxt, int authenticated,
|
|
const struct sshkey *key)
|
|
{
|
|
struct sshkey **tmp, *dup;
|
|
int r;
|
|
|
|
if ((r = sshkey_from_private(key, &dup)) != 0)
|
|
fatal_fr(r, "copy key");
|
|
sshkey_free(authctxt->auth_method_key);
|
|
authctxt->auth_method_key = dup;
|
|
|
|
if (!authenticated)
|
|
return;
|
|
|
|
/* If authenticated, make sure we don't accept this key again */
|
|
if ((r = sshkey_from_private(key, &dup)) != 0)
|
|
fatal_fr(r, "copy key");
|
|
if (authctxt->nprev_keys >= INT_MAX ||
|
|
(tmp = recallocarray(authctxt->prev_keys, authctxt->nprev_keys,
|
|
authctxt->nprev_keys + 1, sizeof(*authctxt->prev_keys))) == NULL)
|
|
fatal_f("reallocarray failed");
|
|
authctxt->prev_keys = tmp;
|
|
authctxt->prev_keys[authctxt->nprev_keys] = dup;
|
|
authctxt->nprev_keys++;
|
|
|
|
}
|
|
|
|
/* Checks whether a key has already been previously used for authentication */
|
|
int
|
|
auth2_key_already_used(Authctxt *authctxt, const struct sshkey *key)
|
|
{
|
|
u_int i;
|
|
char *fp;
|
|
|
|
for (i = 0; i < authctxt->nprev_keys; i++) {
|
|
if (sshkey_equal_public(key, authctxt->prev_keys[i])) {
|
|
fp = sshkey_fingerprint(authctxt->prev_keys[i],
|
|
options.fingerprint_hash, SSH_FP_DEFAULT);
|
|
debug3_f("key already used: %s %s",
|
|
sshkey_type(authctxt->prev_keys[i]),
|
|
fp == NULL ? "UNKNOWN" : fp);
|
|
free(fp);
|
|
return 1;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Updates authctxt->session_info with details of authentication. Should be
|
|
* whenever an authentication method succeeds.
|
|
*/
|
|
void
|
|
auth2_update_session_info(Authctxt *authctxt, const char *method,
|
|
const char *submethod)
|
|
{
|
|
int r;
|
|
|
|
if (authctxt->session_info == NULL) {
|
|
if ((authctxt->session_info = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new");
|
|
}
|
|
|
|
/* Append method[/submethod] */
|
|
if ((r = sshbuf_putf(authctxt->session_info, "%s%s%s",
|
|
method, submethod == NULL ? "" : "/",
|
|
submethod == NULL ? "" : submethod)) != 0)
|
|
fatal_fr(r, "append method");
|
|
|
|
/* Append key if present */
|
|
if (authctxt->auth_method_key != NULL) {
|
|
if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 ||
|
|
(r = sshkey_format_text(authctxt->auth_method_key,
|
|
authctxt->session_info)) != 0)
|
|
fatal_fr(r, "append key");
|
|
}
|
|
|
|
if (authctxt->auth_method_info != NULL) {
|
|
/* Ensure no ambiguity here */
|
|
if (strchr(authctxt->auth_method_info, '\n') != NULL)
|
|
fatal_f("auth_method_info contains \\n");
|
|
if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 ||
|
|
(r = sshbuf_putf(authctxt->session_info, "%s",
|
|
authctxt->auth_method_info)) != 0) {
|
|
fatal_fr(r, "append method info");
|
|
}
|
|
}
|
|
if ((r = sshbuf_put_u8(authctxt->session_info, '\n')) != 0)
|
|
fatal_fr(r, "append");
|
|
}
|
|
|