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
2297 lines
59 KiB
C
2297 lines
59 KiB
C
/* $OpenBSD: ssh-agent.c,v 1.297 2023/03/09 21:06:24 jcs Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* The authentication agent program.
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*
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* Copyright (c) 2000, 2001 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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#include <sys/types.h>
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#include <sys/resource.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/wait.h>
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#ifdef HAVE_SYS_TIME_H
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# include <sys/time.h>
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#endif
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#ifdef HAVE_SYS_UN_H
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# include <sys/un.h>
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#endif
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#include "openbsd-compat/sys-queue.h"
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#ifdef WITH_OPENSSL
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#include <openssl/evp.h>
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#include "openbsd-compat/openssl-compat.h"
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#endif
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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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#ifdef HAVE_PATHS_H
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# include <paths.h>
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#endif
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#ifdef HAVE_POLL_H
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# include <poll.h>
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#endif
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#include <signal.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef HAVE_UTIL_H
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# include <util.h>
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#endif
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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 "sshkey.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 "digest.h"
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#include "ssherr.h"
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#include "match.h"
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#include "msg.h"
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#include "pathnames.h"
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#include "ssh-pkcs11.h"
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#include "sk-api.h"
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#include "myproposal.h"
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#ifndef DEFAULT_ALLOWED_PROVIDERS
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# define DEFAULT_ALLOWED_PROVIDERS "/usr/lib*/*,/usr/local/lib*/*"
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#endif
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/* Maximum accepted message length */
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#define AGENT_MAX_LEN (256*1024)
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/* Maximum bytes to read from client socket */
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#define AGENT_RBUF_LEN (4096)
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/* Maximum number of recorded session IDs/hostkeys per connection */
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#define AGENT_MAX_SESSION_IDS 16
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/* Maximum size of session ID */
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#define AGENT_MAX_SID_LEN 128
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/* Maximum number of destination constraints to accept on a key */
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#define AGENT_MAX_DEST_CONSTRAINTS 1024
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/* XXX store hostkey_sid in a refcounted tree */
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typedef enum {
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AUTH_UNUSED = 0,
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AUTH_SOCKET = 1,
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AUTH_CONNECTION = 2,
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} sock_type;
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struct hostkey_sid {
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struct sshkey *key;
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struct sshbuf *sid;
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int forwarded;
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};
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typedef struct socket_entry {
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int fd;
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sock_type type;
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struct sshbuf *input;
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struct sshbuf *output;
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struct sshbuf *request;
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size_t nsession_ids;
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struct hostkey_sid *session_ids;
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} SocketEntry;
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u_int sockets_alloc = 0;
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SocketEntry *sockets = NULL;
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typedef struct identity {
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TAILQ_ENTRY(identity) next;
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struct sshkey *key;
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char *comment;
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char *provider;
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time_t death;
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u_int confirm;
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char *sk_provider;
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struct dest_constraint *dest_constraints;
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size_t ndest_constraints;
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} Identity;
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struct idtable {
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int nentries;
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TAILQ_HEAD(idqueue, identity) idlist;
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};
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/* private key table */
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struct idtable *idtab;
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int max_fd = 0;
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/* pid of shell == parent of agent */
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pid_t parent_pid = -1;
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time_t parent_alive_interval = 0;
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/* pid of process for which cleanup_socket is applicable */
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pid_t cleanup_pid = 0;
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/* pathname and directory for AUTH_SOCKET */
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char socket_name[PATH_MAX];
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char socket_dir[PATH_MAX];
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/* Pattern-list of allowed PKCS#11/Security key paths */
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static char *allowed_providers;
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/* locking */
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#define LOCK_SIZE 32
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#define LOCK_SALT_SIZE 16
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#define LOCK_ROUNDS 1
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int locked = 0;
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u_char lock_pwhash[LOCK_SIZE];
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u_char lock_salt[LOCK_SALT_SIZE];
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extern char *__progname;
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/* Default lifetime in seconds (0 == forever) */
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static int lifetime = 0;
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static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
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/* Refuse signing of non-SSH messages for web-origin FIDO keys */
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static int restrict_websafe = 1;
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/*
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* Client connection count; incremented in new_socket() and decremented in
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* close_socket(). When it reaches 0, ssh-agent will exit. Since it is
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* normally initialized to 1, it will never reach 0. However, if the -x
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* option is specified, it is initialized to 0 in main(); in that case,
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* ssh-agent will exit as soon as it has had at least one client but no
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* longer has any.
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*/
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static int xcount = 1;
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static void
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close_socket(SocketEntry *e)
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{
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size_t i;
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int last = 0;
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if (e->type == AUTH_CONNECTION) {
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debug("xcount %d -> %d", xcount, xcount - 1);
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if (--xcount == 0)
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last = 1;
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}
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close(e->fd);
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sshbuf_free(e->input);
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sshbuf_free(e->output);
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sshbuf_free(e->request);
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for (i = 0; i < e->nsession_ids; i++) {
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sshkey_free(e->session_ids[i].key);
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sshbuf_free(e->session_ids[i].sid);
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}
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free(e->session_ids);
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memset(e, '\0', sizeof(*e));
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e->fd = -1;
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e->type = AUTH_UNUSED;
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if (last)
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cleanup_exit(0);
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}
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static void
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idtab_init(void)
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{
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idtab = xcalloc(1, sizeof(*idtab));
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TAILQ_INIT(&idtab->idlist);
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idtab->nentries = 0;
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}
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static void
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free_dest_constraint_hop(struct dest_constraint_hop *dch)
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{
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u_int i;
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if (dch == NULL)
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return;
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free(dch->user);
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free(dch->hostname);
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for (i = 0; i < dch->nkeys; i++)
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sshkey_free(dch->keys[i]);
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free(dch->keys);
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free(dch->key_is_ca);
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}
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static void
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free_dest_constraints(struct dest_constraint *dcs, size_t ndcs)
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{
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size_t i;
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for (i = 0; i < ndcs; i++) {
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free_dest_constraint_hop(&dcs[i].from);
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free_dest_constraint_hop(&dcs[i].to);
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}
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free(dcs);
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}
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static void
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free_identity(Identity *id)
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{
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sshkey_free(id->key);
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free(id->provider);
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free(id->comment);
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free(id->sk_provider);
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free_dest_constraints(id->dest_constraints, id->ndest_constraints);
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free(id);
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}
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/*
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* Match 'key' against the key/CA list in a destination constraint hop
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* Returns 0 on success or -1 otherwise.
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*/
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static int
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match_key_hop(const char *tag, const struct sshkey *key,
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const struct dest_constraint_hop *dch)
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{
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const char *reason = NULL;
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const char *hostname = dch->hostname ? dch->hostname : "(ORIGIN)";
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u_int i;
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char *fp;
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if (key == NULL)
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return -1;
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/* XXX logspam */
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if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
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SSH_FP_DEFAULT)) == NULL)
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fatal_f("fingerprint failed");
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debug3_f("%s: entering hostname %s, requested key %s %s, %u keys avail",
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tag, hostname, sshkey_type(key), fp, dch->nkeys);
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free(fp);
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for (i = 0; i < dch->nkeys; i++) {
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if (dch->keys[i] == NULL)
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return -1;
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/* XXX logspam */
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if ((fp = sshkey_fingerprint(dch->keys[i], SSH_FP_HASH_DEFAULT,
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SSH_FP_DEFAULT)) == NULL)
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fatal_f("fingerprint failed");
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debug3_f("%s: key %u: %s%s %s", tag, i,
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dch->key_is_ca[i] ? "CA " : "",
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sshkey_type(dch->keys[i]), fp);
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free(fp);
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if (!sshkey_is_cert(key)) {
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/* plain key */
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if (dch->key_is_ca[i] ||
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!sshkey_equal(key, dch->keys[i]))
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continue;
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return 0;
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}
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/* certificate */
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if (!dch->key_is_ca[i])
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continue;
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if (key->cert == NULL || key->cert->signature_key == NULL)
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return -1; /* shouldn't happen */
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if (!sshkey_equal(key->cert->signature_key, dch->keys[i]))
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continue;
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if (sshkey_cert_check_host(key, hostname, 1,
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SSH_ALLOWED_CA_SIGALGS, &reason) != 0) {
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debug_f("cert %s / hostname %s rejected: %s",
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key->cert->key_id, hostname, reason);
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continue;
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}
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return 0;
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}
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return -1;
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}
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/* Check destination constraints on an identity against the hostkey/user */
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static int
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permitted_by_dest_constraints(const struct sshkey *fromkey,
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const struct sshkey *tokey, Identity *id, const char *user,
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const char **hostnamep)
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{
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size_t i;
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struct dest_constraint *d;
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if (hostnamep != NULL)
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*hostnamep = NULL;
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for (i = 0; i < id->ndest_constraints; i++) {
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d = id->dest_constraints + i;
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/* XXX remove logspam */
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debug2_f("constraint %zu %s%s%s (%u keys) > %s%s%s (%u keys)",
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i, d->from.user ? d->from.user : "",
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d->from.user ? "@" : "",
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d->from.hostname ? d->from.hostname : "(ORIGIN)",
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d->from.nkeys,
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d->to.user ? d->to.user : "", d->to.user ? "@" : "",
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d->to.hostname ? d->to.hostname : "(ANY)", d->to.nkeys);
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/* Match 'from' key */
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if (fromkey == NULL) {
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/* We are matching the first hop */
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if (d->from.hostname != NULL || d->from.nkeys != 0)
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continue;
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} else if (match_key_hop("from", fromkey, &d->from) != 0)
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continue;
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/* Match 'to' key */
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if (tokey != NULL && match_key_hop("to", tokey, &d->to) != 0)
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continue;
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/* Match user if specified */
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if (d->to.user != NULL && user != NULL &&
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!match_pattern(user, d->to.user))
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continue;
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/* successfully matched this constraint */
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if (hostnamep != NULL)
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*hostnamep = d->to.hostname;
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debug2_f("allowed for hostname %s",
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d->to.hostname == NULL ? "*" : d->to.hostname);
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return 0;
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}
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/* no match */
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debug2_f("%s identity \"%s\" not permitted for this destination",
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sshkey_type(id->key), id->comment);
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return -1;
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}
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/*
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* Check whether hostkeys on a SocketEntry and the optionally specified user
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* are permitted by the destination constraints on the Identity.
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* Returns 0 on success or -1 otherwise.
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*/
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static int
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identity_permitted(Identity *id, SocketEntry *e, char *user,
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const char **forward_hostnamep, const char **last_hostnamep)
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{
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size_t i;
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const char **hp;
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struct hostkey_sid *hks;
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const struct sshkey *fromkey = NULL;
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const char *test_user;
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char *fp1, *fp2;
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/* XXX remove logspam */
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debug3_f("entering: key %s comment \"%s\", %zu socket bindings, "
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"%zu constraints", sshkey_type(id->key), id->comment,
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e->nsession_ids, id->ndest_constraints);
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if (id->ndest_constraints == 0)
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return 0; /* unconstrained */
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if (e->nsession_ids == 0)
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return 0; /* local use */
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/*
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* Walk through the hops recorded by session_id and try to find a
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* constraint that satisfies each.
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*/
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for (i = 0; i < e->nsession_ids; i++) {
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hks = e->session_ids + i;
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if (hks->key == NULL)
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fatal_f("internal error: no bound key");
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/* XXX remove logspam */
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fp1 = fp2 = NULL;
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if (fromkey != NULL &&
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(fp1 = sshkey_fingerprint(fromkey, SSH_FP_HASH_DEFAULT,
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SSH_FP_DEFAULT)) == NULL)
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fatal_f("fingerprint failed");
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if ((fp2 = sshkey_fingerprint(hks->key, SSH_FP_HASH_DEFAULT,
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SSH_FP_DEFAULT)) == NULL)
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fatal_f("fingerprint failed");
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debug3_f("socketentry fd=%d, entry %zu %s, "
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"from hostkey %s %s to user %s hostkey %s %s",
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e->fd, i, hks->forwarded ? "FORWARD" : "AUTH",
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fromkey ? sshkey_type(fromkey) : "(ORIGIN)",
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fromkey ? fp1 : "", user ? user : "(ANY)",
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sshkey_type(hks->key), fp2);
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free(fp1);
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free(fp2);
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/*
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* Record the hostnames for the initial forwarding and
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* the final destination.
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*/
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hp = NULL;
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if (i == e->nsession_ids - 1)
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hp = last_hostnamep;
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else if (i == 0)
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hp = forward_hostnamep;
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/* Special handling for final recorded binding */
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test_user = NULL;
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if (i == e->nsession_ids - 1) {
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/* Can only check user at final hop */
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test_user = user;
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/*
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* user is only presented for signature requests.
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* If this is the case, make sure last binding is not
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* for a forwarding.
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*/
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if (hks->forwarded && user != NULL) {
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error_f("tried to sign on forwarding hop");
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return -1;
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}
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} else if (!hks->forwarded) {
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error_f("tried to forward though signing bind");
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return -1;
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}
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if (permitted_by_dest_constraints(fromkey, hks->key, id,
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test_user, hp) != 0)
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return -1;
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fromkey = hks->key;
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}
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/*
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* Another special case: if the last bound session ID was for a
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* forwarding, and this function is not being called to check a sign
|
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* request (i.e. no 'user' supplied), then only permit the key if
|
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* there is a permission that would allow it to be used at another
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* destination. This hides keys that are allowed to be used to
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* authenticate *to* a host but not permitted for *use* beyond it.
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*/
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hks = &e->session_ids[e->nsession_ids - 1];
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if (hks->forwarded && user == NULL &&
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permitted_by_dest_constraints(hks->key, NULL, id,
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NULL, NULL) != 0) {
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debug3_f("key permitted at host but not after");
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return -1;
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}
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|
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/* success */
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return 0;
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}
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|
|
/* return matching private key for given public key */
|
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static Identity *
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lookup_identity(struct sshkey *key)
|
|
{
|
|
Identity *id;
|
|
|
|
TAILQ_FOREACH(id, &idtab->idlist, next) {
|
|
if (sshkey_equal(key, id->key))
|
|
return (id);
|
|
}
|
|
return (NULL);
|
|
}
|
|
|
|
/* Check confirmation of keysign request */
|
|
static int
|
|
confirm_key(Identity *id, const char *extra)
|
|
{
|
|
char *p;
|
|
int ret = -1;
|
|
|
|
p = sshkey_fingerprint(id->key, fingerprint_hash, SSH_FP_DEFAULT);
|
|
if (p != NULL &&
|
|
ask_permission("Allow use of key %s?\nKey fingerprint %s.%s%s",
|
|
id->comment, p,
|
|
extra == NULL ? "" : "\n", extra == NULL ? "" : extra))
|
|
ret = 0;
|
|
free(p);
|
|
|
|
return (ret);
|
|
}
|
|
|
|
static void
|
|
send_status(SocketEntry *e, int success)
|
|
{
|
|
int r;
|
|
|
|
if ((r = sshbuf_put_u32(e->output, 1)) != 0 ||
|
|
(r = sshbuf_put_u8(e->output, success ?
|
|
SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE)) != 0)
|
|
fatal_fr(r, "compose");
|
|
}
|
|
|
|
/* send list of supported public keys to 'client' */
|
|
static void
|
|
process_request_identities(SocketEntry *e)
|
|
{
|
|
Identity *id;
|
|
struct sshbuf *msg, *keys;
|
|
int r;
|
|
u_int nentries = 0;
|
|
|
|
debug2_f("entering");
|
|
|
|
if ((msg = sshbuf_new()) == NULL || (keys = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
TAILQ_FOREACH(id, &idtab->idlist, next) {
|
|
/* identity not visible, don't include in response */
|
|
if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
|
|
continue;
|
|
if ((r = sshkey_puts_opts(id->key, keys,
|
|
SSHKEY_SERIALIZE_INFO)) != 0 ||
|
|
(r = sshbuf_put_cstring(keys, id->comment)) != 0) {
|
|
error_fr(r, "compose key/comment");
|
|
continue;
|
|
}
|
|
nentries++;
|
|
}
|
|
debug2_f("replying with %u allowed of %u available keys",
|
|
nentries, idtab->nentries);
|
|
if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
|
|
(r = sshbuf_put_u32(msg, nentries)) != 0 ||
|
|
(r = sshbuf_putb(msg, keys)) != 0)
|
|
fatal_fr(r, "compose");
|
|
if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
|
|
fatal_fr(r, "enqueue");
|
|
sshbuf_free(msg);
|
|
sshbuf_free(keys);
|
|
}
|
|
|
|
|
|
static char *
|
|
agent_decode_alg(struct sshkey *key, u_int flags)
|
|
{
|
|
if (key->type == KEY_RSA) {
|
|
if (flags & SSH_AGENT_RSA_SHA2_256)
|
|
return "rsa-sha2-256";
|
|
else if (flags & SSH_AGENT_RSA_SHA2_512)
|
|
return "rsa-sha2-512";
|
|
} else if (key->type == KEY_RSA_CERT) {
|
|
if (flags & SSH_AGENT_RSA_SHA2_256)
|
|
return "rsa-sha2-256-cert-v01@openssh.com";
|
|
else if (flags & SSH_AGENT_RSA_SHA2_512)
|
|
return "rsa-sha2-512-cert-v01@openssh.com";
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Attempt to parse the contents of a buffer as a SSH publickey userauth
|
|
* request, checking its contents for consistency and matching the embedded
|
|
* key against the one that is being used for signing.
|
|
* Note: does not modify msg buffer.
|
|
* Optionally extract the username, session ID and/or hostkey from the request.
|
|
*/
|
|
static int
|
|
parse_userauth_request(struct sshbuf *msg, const struct sshkey *expected_key,
|
|
char **userp, struct sshbuf **sess_idp, struct sshkey **hostkeyp)
|
|
{
|
|
struct sshbuf *b = NULL, *sess_id = NULL;
|
|
char *user = NULL, *service = NULL, *method = NULL, *pkalg = NULL;
|
|
int r;
|
|
u_char t, sig_follows;
|
|
struct sshkey *mkey = NULL, *hostkey = NULL;
|
|
|
|
if (userp != NULL)
|
|
*userp = NULL;
|
|
if (sess_idp != NULL)
|
|
*sess_idp = NULL;
|
|
if (hostkeyp != NULL)
|
|
*hostkeyp = NULL;
|
|
if ((b = sshbuf_fromb(msg)) == NULL)
|
|
fatal_f("sshbuf_fromb");
|
|
|
|
/* SSH userauth request */
|
|
if ((r = sshbuf_froms(b, &sess_id)) != 0)
|
|
goto out;
|
|
if (sshbuf_len(sess_id) == 0) {
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_get_u8(b, &t)) != 0 || /* SSH2_MSG_USERAUTH_REQUEST */
|
|
(r = sshbuf_get_cstring(b, &user, NULL)) != 0 || /* server user */
|
|
(r = sshbuf_get_cstring(b, &service, NULL)) != 0 || /* service */
|
|
(r = sshbuf_get_cstring(b, &method, NULL)) != 0 || /* method */
|
|
(r = sshbuf_get_u8(b, &sig_follows)) != 0 || /* sig-follows */
|
|
(r = sshbuf_get_cstring(b, &pkalg, NULL)) != 0 || /* alg */
|
|
(r = sshkey_froms(b, &mkey)) != 0) /* key */
|
|
goto out;
|
|
if (t != SSH2_MSG_USERAUTH_REQUEST ||
|
|
sig_follows != 1 ||
|
|
strcmp(service, "ssh-connection") != 0 ||
|
|
!sshkey_equal(expected_key, mkey) ||
|
|
sshkey_type_from_name(pkalg) != expected_key->type) {
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if (strcmp(method, "publickey-hostbound-v00@openssh.com") == 0) {
|
|
if ((r = sshkey_froms(b, &hostkey)) != 0)
|
|
goto out;
|
|
} else if (strcmp(method, "publickey") != 0) {
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if (sshbuf_len(b) != 0) {
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
debug3_f("well formed userauth");
|
|
if (userp != NULL) {
|
|
*userp = user;
|
|
user = NULL;
|
|
}
|
|
if (sess_idp != NULL) {
|
|
*sess_idp = sess_id;
|
|
sess_id = NULL;
|
|
}
|
|
if (hostkeyp != NULL) {
|
|
*hostkeyp = hostkey;
|
|
hostkey = NULL;
|
|
}
|
|
out:
|
|
sshbuf_free(b);
|
|
sshbuf_free(sess_id);
|
|
free(user);
|
|
free(service);
|
|
free(method);
|
|
free(pkalg);
|
|
sshkey_free(mkey);
|
|
sshkey_free(hostkey);
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* Attempt to parse the contents of a buffer as a SSHSIG signature request.
|
|
* Note: does not modify buffer.
|
|
*/
|
|
static int
|
|
parse_sshsig_request(struct sshbuf *msg)
|
|
{
|
|
int r;
|
|
struct sshbuf *b;
|
|
|
|
if ((b = sshbuf_fromb(msg)) == NULL)
|
|
fatal_f("sshbuf_fromb");
|
|
|
|
if ((r = sshbuf_cmp(b, 0, "SSHSIG", 6)) != 0 ||
|
|
(r = sshbuf_consume(b, 6)) != 0 ||
|
|
(r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* namespace */
|
|
(r = sshbuf_get_string_direct(b, NULL, NULL)) != 0 || /* reserved */
|
|
(r = sshbuf_get_cstring(b, NULL, NULL)) != 0 || /* hashalg */
|
|
(r = sshbuf_get_string_direct(b, NULL, NULL)) != 0) /* H(msg) */
|
|
goto out;
|
|
if (sshbuf_len(b) != 0) {
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
sshbuf_free(b);
|
|
return r;
|
|
}
|
|
|
|
/*
|
|
* This function inspects a message to be signed by a FIDO key that has a
|
|
* web-like application string (i.e. one that does not begin with "ssh:".
|
|
* It checks that the message is one of those expected for SSH operations
|
|
* (pubkey userauth, sshsig, CA key signing) to exclude signing challenges
|
|
* for the web.
|
|
*/
|
|
static int
|
|
check_websafe_message_contents(struct sshkey *key, struct sshbuf *data)
|
|
{
|
|
if (parse_userauth_request(data, key, NULL, NULL, NULL) == 0) {
|
|
debug_f("signed data matches public key userauth request");
|
|
return 1;
|
|
}
|
|
if (parse_sshsig_request(data) == 0) {
|
|
debug_f("signed data matches SSHSIG signature request");
|
|
return 1;
|
|
}
|
|
|
|
/* XXX check CA signature operation */
|
|
|
|
error("web-origin key attempting to sign non-SSH message");
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
buf_equal(const struct sshbuf *a, const struct sshbuf *b)
|
|
{
|
|
if (sshbuf_ptr(a) == NULL || sshbuf_ptr(b) == NULL)
|
|
return SSH_ERR_INVALID_ARGUMENT;
|
|
if (sshbuf_len(a) != sshbuf_len(b))
|
|
return SSH_ERR_INVALID_FORMAT;
|
|
if (timingsafe_bcmp(sshbuf_ptr(a), sshbuf_ptr(b), sshbuf_len(a)) != 0)
|
|
return SSH_ERR_INVALID_FORMAT;
|
|
return 0;
|
|
}
|
|
|
|
/* ssh2 only */
|
|
static void
|
|
process_sign_request2(SocketEntry *e)
|
|
{
|
|
u_char *signature = NULL;
|
|
size_t slen = 0;
|
|
u_int compat = 0, flags;
|
|
int r, ok = -1, retried = 0;
|
|
char *fp = NULL, *pin = NULL, *prompt = NULL;
|
|
char *user = NULL, *sig_dest = NULL;
|
|
const char *fwd_host = NULL, *dest_host = NULL;
|
|
struct sshbuf *msg = NULL, *data = NULL, *sid = NULL;
|
|
struct sshkey *key = NULL, *hostkey = NULL;
|
|
struct identity *id;
|
|
struct notifier_ctx *notifier = NULL;
|
|
|
|
debug_f("entering");
|
|
|
|
if ((msg = sshbuf_new()) == NULL || (data = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
if ((r = sshkey_froms(e->request, &key)) != 0 ||
|
|
(r = sshbuf_get_stringb(e->request, data)) != 0 ||
|
|
(r = sshbuf_get_u32(e->request, &flags)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto send;
|
|
}
|
|
|
|
if ((id = lookup_identity(key)) == NULL) {
|
|
verbose_f("%s key not found", sshkey_type(key));
|
|
goto send;
|
|
}
|
|
if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
|
|
SSH_FP_DEFAULT)) == NULL)
|
|
fatal_f("fingerprint failed");
|
|
|
|
if (id->ndest_constraints != 0) {
|
|
if (e->nsession_ids == 0) {
|
|
logit_f("refusing use of destination-constrained key "
|
|
"to sign on unbound connection");
|
|
goto send;
|
|
}
|
|
if (parse_userauth_request(data, key, &user, &sid,
|
|
&hostkey) != 0) {
|
|
logit_f("refusing use of destination-constrained key "
|
|
"to sign an unidentified signature");
|
|
goto send;
|
|
}
|
|
/* XXX logspam */
|
|
debug_f("user=%s", user);
|
|
if (identity_permitted(id, e, user, &fwd_host, &dest_host) != 0)
|
|
goto send;
|
|
/* XXX display fwd_host/dest_host in askpass UI */
|
|
/*
|
|
* Ensure that the session ID is the most recent one
|
|
* registered on the socket - it should have been bound by
|
|
* ssh immediately before userauth.
|
|
*/
|
|
if (buf_equal(sid,
|
|
e->session_ids[e->nsession_ids - 1].sid) != 0) {
|
|
error_f("unexpected session ID (%zu listed) on "
|
|
"signature request for target user %s with "
|
|
"key %s %s", e->nsession_ids, user,
|
|
sshkey_type(id->key), fp);
|
|
goto send;
|
|
}
|
|
/*
|
|
* Ensure that the hostkey embedded in the signature matches
|
|
* the one most recently bound to the socket. An exception is
|
|
* made for the initial forwarding hop.
|
|
*/
|
|
if (e->nsession_ids > 1 && hostkey == NULL) {
|
|
error_f("refusing use of destination-constrained key: "
|
|
"no hostkey recorded in signature for forwarded "
|
|
"connection");
|
|
goto send;
|
|
}
|
|
if (hostkey != NULL && !sshkey_equal(hostkey,
|
|
e->session_ids[e->nsession_ids - 1].key)) {
|
|
error_f("refusing use of destination-constrained key: "
|
|
"mismatch between hostkey in request and most "
|
|
"recently bound session");
|
|
goto send;
|
|
}
|
|
xasprintf(&sig_dest, "public key authentication request for "
|
|
"user \"%s\" to listed host", user);
|
|
}
|
|
if (id->confirm && confirm_key(id, sig_dest) != 0) {
|
|
verbose_f("user refused key");
|
|
goto send;
|
|
}
|
|
if (sshkey_is_sk(id->key)) {
|
|
if (restrict_websafe &&
|
|
strncmp(id->key->sk_application, "ssh:", 4) != 0 &&
|
|
!check_websafe_message_contents(key, data)) {
|
|
/* error already logged */
|
|
goto send;
|
|
}
|
|
if (id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) {
|
|
notifier = notify_start(0,
|
|
"Confirm user presence for key %s %s%s%s",
|
|
sshkey_type(id->key), fp,
|
|
sig_dest == NULL ? "" : "\n",
|
|
sig_dest == NULL ? "" : sig_dest);
|
|
}
|
|
}
|
|
retry_pin:
|
|
if ((r = sshkey_sign(id->key, &signature, &slen,
|
|
sshbuf_ptr(data), sshbuf_len(data), agent_decode_alg(key, flags),
|
|
id->sk_provider, pin, compat)) != 0) {
|
|
debug_fr(r, "sshkey_sign");
|
|
if (pin == NULL && !retried && sshkey_is_sk(id->key) &&
|
|
r == SSH_ERR_KEY_WRONG_PASSPHRASE) {
|
|
notify_complete(notifier, NULL);
|
|
notifier = NULL;
|
|
/* XXX include sig_dest */
|
|
xasprintf(&prompt, "Enter PIN%sfor %s key %s: ",
|
|
(id->key->sk_flags & SSH_SK_USER_PRESENCE_REQD) ?
|
|
" and confirm user presence " : " ",
|
|
sshkey_type(id->key), fp);
|
|
pin = read_passphrase(prompt, RP_USE_ASKPASS);
|
|
retried = 1;
|
|
goto retry_pin;
|
|
}
|
|
error_fr(r, "sshkey_sign");
|
|
goto send;
|
|
}
|
|
/* Success */
|
|
ok = 0;
|
|
send:
|
|
debug_f("good signature");
|
|
notify_complete(notifier, "User presence confirmed");
|
|
|
|
if (ok == 0) {
|
|
if ((r = sshbuf_put_u8(msg, SSH2_AGENT_SIGN_RESPONSE)) != 0 ||
|
|
(r = sshbuf_put_string(msg, signature, slen)) != 0)
|
|
fatal_fr(r, "compose");
|
|
} else if ((r = sshbuf_put_u8(msg, SSH_AGENT_FAILURE)) != 0)
|
|
fatal_fr(r, "compose failure");
|
|
|
|
if ((r = sshbuf_put_stringb(e->output, msg)) != 0)
|
|
fatal_fr(r, "enqueue");
|
|
|
|
sshbuf_free(sid);
|
|
sshbuf_free(data);
|
|
sshbuf_free(msg);
|
|
sshkey_free(key);
|
|
sshkey_free(hostkey);
|
|
free(fp);
|
|
free(signature);
|
|
free(sig_dest);
|
|
free(user);
|
|
free(prompt);
|
|
if (pin != NULL)
|
|
freezero(pin, strlen(pin));
|
|
}
|
|
|
|
/* shared */
|
|
static void
|
|
process_remove_identity(SocketEntry *e)
|
|
{
|
|
int r, success = 0;
|
|
struct sshkey *key = NULL;
|
|
Identity *id;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshkey_froms(e->request, &key)) != 0) {
|
|
error_fr(r, "parse key");
|
|
goto done;
|
|
}
|
|
if ((id = lookup_identity(key)) == NULL) {
|
|
debug_f("key not found");
|
|
goto done;
|
|
}
|
|
/* identity not visible, cannot be removed */
|
|
if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
|
|
goto done; /* error already logged */
|
|
/* We have this key, free it. */
|
|
if (idtab->nentries < 1)
|
|
fatal_f("internal error: nentries %d", idtab->nentries);
|
|
TAILQ_REMOVE(&idtab->idlist, id, next);
|
|
free_identity(id);
|
|
idtab->nentries--;
|
|
success = 1;
|
|
done:
|
|
sshkey_free(key);
|
|
send_status(e, success);
|
|
}
|
|
|
|
static void
|
|
process_remove_all_identities(SocketEntry *e)
|
|
{
|
|
Identity *id;
|
|
|
|
debug2_f("entering");
|
|
/* Loop over all identities and clear the keys. */
|
|
for (id = TAILQ_FIRST(&idtab->idlist); id;
|
|
id = TAILQ_FIRST(&idtab->idlist)) {
|
|
TAILQ_REMOVE(&idtab->idlist, id, next);
|
|
free_identity(id);
|
|
}
|
|
|
|
/* Mark that there are no identities. */
|
|
idtab->nentries = 0;
|
|
|
|
/* Send success. */
|
|
send_status(e, 1);
|
|
}
|
|
|
|
/* removes expired keys and returns number of seconds until the next expiry */
|
|
static time_t
|
|
reaper(void)
|
|
{
|
|
time_t deadline = 0, now = monotime();
|
|
Identity *id, *nxt;
|
|
|
|
for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
|
|
nxt = TAILQ_NEXT(id, next);
|
|
if (id->death == 0)
|
|
continue;
|
|
if (now >= id->death) {
|
|
debug("expiring key '%s'", id->comment);
|
|
TAILQ_REMOVE(&idtab->idlist, id, next);
|
|
free_identity(id);
|
|
idtab->nentries--;
|
|
} else
|
|
deadline = (deadline == 0) ? id->death :
|
|
MINIMUM(deadline, id->death);
|
|
}
|
|
if (deadline == 0 || deadline <= now)
|
|
return 0;
|
|
else
|
|
return (deadline - now);
|
|
}
|
|
|
|
static int
|
|
parse_dest_constraint_hop(struct sshbuf *b, struct dest_constraint_hop *dch)
|
|
{
|
|
u_char key_is_ca;
|
|
size_t elen = 0;
|
|
int r;
|
|
struct sshkey *k = NULL;
|
|
char *fp;
|
|
|
|
memset(dch, '\0', sizeof(*dch));
|
|
if ((r = sshbuf_get_cstring(b, &dch->user, NULL)) != 0 ||
|
|
(r = sshbuf_get_cstring(b, &dch->hostname, NULL)) != 0 ||
|
|
(r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto out;
|
|
}
|
|
if (elen != 0) {
|
|
error_f("unsupported extensions (len %zu)", elen);
|
|
r = SSH_ERR_FEATURE_UNSUPPORTED;
|
|
goto out;
|
|
}
|
|
if (*dch->hostname == '\0') {
|
|
free(dch->hostname);
|
|
dch->hostname = NULL;
|
|
}
|
|
if (*dch->user == '\0') {
|
|
free(dch->user);
|
|
dch->user = NULL;
|
|
}
|
|
while (sshbuf_len(b) != 0) {
|
|
dch->keys = xrecallocarray(dch->keys, dch->nkeys,
|
|
dch->nkeys + 1, sizeof(*dch->keys));
|
|
dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys,
|
|
dch->nkeys + 1, sizeof(*dch->key_is_ca));
|
|
if ((r = sshkey_froms(b, &k)) != 0 ||
|
|
(r = sshbuf_get_u8(b, &key_is_ca)) != 0)
|
|
goto out;
|
|
if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
|
|
SSH_FP_DEFAULT)) == NULL)
|
|
fatal_f("fingerprint failed");
|
|
debug3_f("%s%s%s: adding %skey %s %s",
|
|
dch->user == NULL ? "" : dch->user,
|
|
dch->user == NULL ? "" : "@",
|
|
dch->hostname, key_is_ca ? "CA " : "", sshkey_type(k), fp);
|
|
free(fp);
|
|
dch->keys[dch->nkeys] = k;
|
|
dch->key_is_ca[dch->nkeys] = key_is_ca != 0;
|
|
dch->nkeys++;
|
|
k = NULL; /* transferred */
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
sshkey_free(k);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
parse_dest_constraint(struct sshbuf *m, struct dest_constraint *dc)
|
|
{
|
|
struct sshbuf *b = NULL, *frombuf = NULL, *tobuf = NULL;
|
|
int r;
|
|
size_t elen = 0;
|
|
|
|
debug3_f("entering");
|
|
|
|
memset(dc, '\0', sizeof(*dc));
|
|
if ((r = sshbuf_froms(m, &b)) != 0 ||
|
|
(r = sshbuf_froms(b, &frombuf)) != 0 ||
|
|
(r = sshbuf_froms(b, &tobuf)) != 0 ||
|
|
(r = sshbuf_get_string_direct(b, NULL, &elen)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto out;
|
|
}
|
|
if ((r = parse_dest_constraint_hop(frombuf, &dc->from)) != 0 ||
|
|
(r = parse_dest_constraint_hop(tobuf, &dc->to)) != 0)
|
|
goto out; /* already logged */
|
|
if (elen != 0) {
|
|
error_f("unsupported extensions (len %zu)", elen);
|
|
r = SSH_ERR_FEATURE_UNSUPPORTED;
|
|
goto out;
|
|
}
|
|
debug2_f("parsed %s (%u keys) > %s%s%s (%u keys)",
|
|
dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys,
|
|
dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "",
|
|
dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys);
|
|
/* check consistency */
|
|
if ((dc->from.hostname == NULL) != (dc->from.nkeys == 0) ||
|
|
dc->from.user != NULL) {
|
|
error_f("inconsistent \"from\" specification");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if (dc->to.hostname == NULL || dc->to.nkeys == 0) {
|
|
error_f("incomplete \"to\" specification");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
sshbuf_free(b);
|
|
sshbuf_free(frombuf);
|
|
sshbuf_free(tobuf);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
|
|
struct dest_constraint **dcsp, size_t *ndcsp)
|
|
{
|
|
char *ext_name = NULL;
|
|
int r;
|
|
struct sshbuf *b = NULL;
|
|
|
|
if ((r = sshbuf_get_cstring(m, &ext_name, NULL)) != 0) {
|
|
error_fr(r, "parse constraint extension");
|
|
goto out;
|
|
}
|
|
debug_f("constraint ext %s", ext_name);
|
|
if (strcmp(ext_name, "sk-provider@openssh.com") == 0) {
|
|
if (sk_providerp == NULL) {
|
|
error_f("%s not valid here", ext_name);
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if (*sk_providerp != NULL) {
|
|
error_f("%s already set", ext_name);
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_get_cstring(m, sk_providerp, NULL)) != 0) {
|
|
error_fr(r, "parse %s", ext_name);
|
|
goto out;
|
|
}
|
|
} else if (strcmp(ext_name,
|
|
"restrict-destination-v00@openssh.com") == 0) {
|
|
if (*dcsp != NULL) {
|
|
error_f("%s already set", ext_name);
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_froms(m, &b)) != 0) {
|
|
error_fr(r, "parse %s outer", ext_name);
|
|
goto out;
|
|
}
|
|
while (sshbuf_len(b) != 0) {
|
|
if (*ndcsp >= AGENT_MAX_DEST_CONSTRAINTS) {
|
|
error_f("too many %s constraints", ext_name);
|
|
goto out;
|
|
}
|
|
*dcsp = xrecallocarray(*dcsp, *ndcsp, *ndcsp + 1,
|
|
sizeof(**dcsp));
|
|
if ((r = parse_dest_constraint(b,
|
|
*dcsp + (*ndcsp)++)) != 0)
|
|
goto out; /* error already logged */
|
|
}
|
|
} else {
|
|
error_f("unsupported constraint \"%s\"", ext_name);
|
|
r = SSH_ERR_FEATURE_UNSUPPORTED;
|
|
goto out;
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
free(ext_name);
|
|
sshbuf_free(b);
|
|
return r;
|
|
}
|
|
|
|
static int
|
|
parse_key_constraints(struct sshbuf *m, struct sshkey *k, time_t *deathp,
|
|
u_int *secondsp, int *confirmp, char **sk_providerp,
|
|
struct dest_constraint **dcsp, size_t *ndcsp)
|
|
{
|
|
u_char ctype;
|
|
int r;
|
|
u_int seconds, maxsign = 0;
|
|
|
|
while (sshbuf_len(m)) {
|
|
if ((r = sshbuf_get_u8(m, &ctype)) != 0) {
|
|
error_fr(r, "parse constraint type");
|
|
goto out;
|
|
}
|
|
switch (ctype) {
|
|
case SSH_AGENT_CONSTRAIN_LIFETIME:
|
|
if (*deathp != 0) {
|
|
error_f("lifetime already set");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_get_u32(m, &seconds)) != 0) {
|
|
error_fr(r, "parse lifetime constraint");
|
|
goto out;
|
|
}
|
|
*deathp = monotime() + seconds;
|
|
*secondsp = seconds;
|
|
break;
|
|
case SSH_AGENT_CONSTRAIN_CONFIRM:
|
|
if (*confirmp != 0) {
|
|
error_f("confirm already set");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
*confirmp = 1;
|
|
break;
|
|
case SSH_AGENT_CONSTRAIN_MAXSIGN:
|
|
if (k == NULL) {
|
|
error_f("maxsign not valid here");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if (maxsign != 0) {
|
|
error_f("maxsign already set");
|
|
r = SSH_ERR_INVALID_FORMAT;
|
|
goto out;
|
|
}
|
|
if ((r = sshbuf_get_u32(m, &maxsign)) != 0) {
|
|
error_fr(r, "parse maxsign constraint");
|
|
goto out;
|
|
}
|
|
if ((r = sshkey_enable_maxsign(k, maxsign)) != 0) {
|
|
error_fr(r, "enable maxsign");
|
|
goto out;
|
|
}
|
|
break;
|
|
case SSH_AGENT_CONSTRAIN_EXTENSION:
|
|
if ((r = parse_key_constraint_extension(m,
|
|
sk_providerp, dcsp, ndcsp)) != 0)
|
|
goto out; /* error already logged */
|
|
break;
|
|
default:
|
|
error_f("Unknown constraint %d", ctype);
|
|
r = SSH_ERR_FEATURE_UNSUPPORTED;
|
|
goto out;
|
|
}
|
|
}
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
return r;
|
|
}
|
|
|
|
static void
|
|
process_add_identity(SocketEntry *e)
|
|
{
|
|
Identity *id;
|
|
int success = 0, confirm = 0;
|
|
char *fp, *comment = NULL, *sk_provider = NULL;
|
|
char canonical_provider[PATH_MAX];
|
|
time_t death = 0;
|
|
u_int seconds = 0;
|
|
struct dest_constraint *dest_constraints = NULL;
|
|
size_t ndest_constraints = 0;
|
|
struct sshkey *k = NULL;
|
|
int r = SSH_ERR_INTERNAL_ERROR;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshkey_private_deserialize(e->request, &k)) != 0 ||
|
|
k == NULL ||
|
|
(r = sshbuf_get_cstring(e->request, &comment, NULL)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto out;
|
|
}
|
|
if (parse_key_constraints(e->request, k, &death, &seconds, &confirm,
|
|
&sk_provider, &dest_constraints, &ndest_constraints) != 0) {
|
|
error_f("failed to parse constraints");
|
|
sshbuf_reset(e->request);
|
|
goto out;
|
|
}
|
|
|
|
if (sk_provider != NULL) {
|
|
if (!sshkey_is_sk(k)) {
|
|
error("Cannot add provider: %s is not an "
|
|
"authenticator-hosted key", sshkey_type(k));
|
|
goto out;
|
|
}
|
|
if (strcasecmp(sk_provider, "internal") == 0) {
|
|
debug_f("internal provider");
|
|
} else {
|
|
if (realpath(sk_provider, canonical_provider) == NULL) {
|
|
verbose("failed provider \"%.100s\": "
|
|
"realpath: %s", sk_provider,
|
|
strerror(errno));
|
|
goto out;
|
|
}
|
|
free(sk_provider);
|
|
sk_provider = xstrdup(canonical_provider);
|
|
if (match_pattern_list(sk_provider,
|
|
allowed_providers, 0) != 1) {
|
|
error("Refusing add key: "
|
|
"provider %s not allowed", sk_provider);
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
if ((r = sshkey_shield_private(k)) != 0) {
|
|
error_fr(r, "shield private");
|
|
goto out;
|
|
}
|
|
if (lifetime && !death)
|
|
death = monotime() + lifetime;
|
|
if ((id = lookup_identity(k)) == NULL) {
|
|
id = xcalloc(1, sizeof(Identity));
|
|
TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
|
|
/* Increment the number of identities. */
|
|
idtab->nentries++;
|
|
} else {
|
|
/* identity not visible, do not update */
|
|
if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
|
|
goto out; /* error already logged */
|
|
/* key state might have been updated */
|
|
sshkey_free(id->key);
|
|
free(id->comment);
|
|
free(id->sk_provider);
|
|
free_dest_constraints(id->dest_constraints,
|
|
id->ndest_constraints);
|
|
}
|
|
/* success */
|
|
id->key = k;
|
|
id->comment = comment;
|
|
id->death = death;
|
|
id->confirm = confirm;
|
|
id->sk_provider = sk_provider;
|
|
id->dest_constraints = dest_constraints;
|
|
id->ndest_constraints = ndest_constraints;
|
|
|
|
if ((fp = sshkey_fingerprint(k, SSH_FP_HASH_DEFAULT,
|
|
SSH_FP_DEFAULT)) == NULL)
|
|
fatal_f("sshkey_fingerprint failed");
|
|
debug_f("add %s %s \"%.100s\" (life: %u) (confirm: %u) "
|
|
"(provider: %s) (destination constraints: %zu)",
|
|
sshkey_ssh_name(k), fp, comment, seconds, confirm,
|
|
sk_provider == NULL ? "none" : sk_provider, ndest_constraints);
|
|
free(fp);
|
|
/* transferred */
|
|
k = NULL;
|
|
comment = NULL;
|
|
sk_provider = NULL;
|
|
dest_constraints = NULL;
|
|
ndest_constraints = 0;
|
|
success = 1;
|
|
out:
|
|
free(sk_provider);
|
|
free(comment);
|
|
sshkey_free(k);
|
|
free_dest_constraints(dest_constraints, ndest_constraints);
|
|
send_status(e, success);
|
|
}
|
|
|
|
/* XXX todo: encrypt sensitive data with passphrase */
|
|
static void
|
|
process_lock_agent(SocketEntry *e, int lock)
|
|
{
|
|
int r, success = 0, delay;
|
|
char *passwd;
|
|
u_char passwdhash[LOCK_SIZE];
|
|
static u_int fail_count = 0;
|
|
size_t pwlen;
|
|
|
|
debug2_f("entering");
|
|
/*
|
|
* This is deliberately fatal: the user has requested that we lock,
|
|
* but we can't parse their request properly. The only safe thing to
|
|
* do is abort.
|
|
*/
|
|
if ((r = sshbuf_get_cstring(e->request, &passwd, &pwlen)) != 0)
|
|
fatal_fr(r, "parse");
|
|
if (pwlen == 0) {
|
|
debug("empty password not supported");
|
|
} else if (locked && !lock) {
|
|
if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
|
|
passwdhash, sizeof(passwdhash), LOCK_ROUNDS) < 0)
|
|
fatal("bcrypt_pbkdf");
|
|
if (timingsafe_bcmp(passwdhash, lock_pwhash, LOCK_SIZE) == 0) {
|
|
debug("agent unlocked");
|
|
locked = 0;
|
|
fail_count = 0;
|
|
explicit_bzero(lock_pwhash, sizeof(lock_pwhash));
|
|
success = 1;
|
|
} else {
|
|
/* delay in 0.1s increments up to 10s */
|
|
if (fail_count < 100)
|
|
fail_count++;
|
|
delay = 100000 * fail_count;
|
|
debug("unlock failed, delaying %0.1lf seconds",
|
|
(double)delay/1000000);
|
|
usleep(delay);
|
|
}
|
|
explicit_bzero(passwdhash, sizeof(passwdhash));
|
|
} else if (!locked && lock) {
|
|
debug("agent locked");
|
|
locked = 1;
|
|
arc4random_buf(lock_salt, sizeof(lock_salt));
|
|
if (bcrypt_pbkdf(passwd, pwlen, lock_salt, sizeof(lock_salt),
|
|
lock_pwhash, sizeof(lock_pwhash), LOCK_ROUNDS) < 0)
|
|
fatal("bcrypt_pbkdf");
|
|
success = 1;
|
|
}
|
|
freezero(passwd, pwlen);
|
|
send_status(e, success);
|
|
}
|
|
|
|
static void
|
|
no_identities(SocketEntry *e)
|
|
{
|
|
struct sshbuf *msg;
|
|
int r;
|
|
|
|
if ((msg = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
if ((r = sshbuf_put_u8(msg, SSH2_AGENT_IDENTITIES_ANSWER)) != 0 ||
|
|
(r = sshbuf_put_u32(msg, 0)) != 0 ||
|
|
(r = sshbuf_put_stringb(e->output, msg)) != 0)
|
|
fatal_fr(r, "compose");
|
|
sshbuf_free(msg);
|
|
}
|
|
|
|
#ifdef ENABLE_PKCS11
|
|
static void
|
|
process_add_smartcard_key(SocketEntry *e)
|
|
{
|
|
char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
|
|
char **comments = NULL;
|
|
int r, i, count = 0, success = 0, confirm = 0;
|
|
u_int seconds = 0;
|
|
time_t death = 0;
|
|
struct sshkey **keys = NULL, *k;
|
|
Identity *id;
|
|
struct dest_constraint *dest_constraints = NULL;
|
|
size_t ndest_constraints = 0;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
|
|
(r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto send;
|
|
}
|
|
if (parse_key_constraints(e->request, NULL, &death, &seconds, &confirm,
|
|
NULL, &dest_constraints, &ndest_constraints) != 0) {
|
|
error_f("failed to parse constraints");
|
|
goto send;
|
|
}
|
|
if (realpath(provider, canonical_provider) == NULL) {
|
|
verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
|
|
provider, strerror(errno));
|
|
goto send;
|
|
}
|
|
if (match_pattern_list(canonical_provider, allowed_providers, 0) != 1) {
|
|
verbose("refusing PKCS#11 add of \"%.100s\": "
|
|
"provider not allowed", canonical_provider);
|
|
goto send;
|
|
}
|
|
debug_f("add %.100s", canonical_provider);
|
|
if (lifetime && !death)
|
|
death = monotime() + lifetime;
|
|
|
|
count = pkcs11_add_provider(canonical_provider, pin, &keys, &comments);
|
|
for (i = 0; i < count; i++) {
|
|
k = keys[i];
|
|
if (lookup_identity(k) == NULL) {
|
|
id = xcalloc(1, sizeof(Identity));
|
|
id->key = k;
|
|
keys[i] = NULL; /* transferred */
|
|
id->provider = xstrdup(canonical_provider);
|
|
if (*comments[i] != '\0') {
|
|
id->comment = comments[i];
|
|
comments[i] = NULL; /* transferred */
|
|
} else {
|
|
id->comment = xstrdup(canonical_provider);
|
|
}
|
|
id->death = death;
|
|
id->confirm = confirm;
|
|
id->dest_constraints = dest_constraints;
|
|
id->ndest_constraints = ndest_constraints;
|
|
dest_constraints = NULL; /* transferred */
|
|
ndest_constraints = 0;
|
|
TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
|
|
idtab->nentries++;
|
|
success = 1;
|
|
}
|
|
/* XXX update constraints for existing keys */
|
|
sshkey_free(keys[i]);
|
|
free(comments[i]);
|
|
}
|
|
send:
|
|
free(pin);
|
|
free(provider);
|
|
free(keys);
|
|
free(comments);
|
|
free_dest_constraints(dest_constraints, ndest_constraints);
|
|
send_status(e, success);
|
|
}
|
|
|
|
static void
|
|
process_remove_smartcard_key(SocketEntry *e)
|
|
{
|
|
char *provider = NULL, *pin = NULL, canonical_provider[PATH_MAX];
|
|
int r, success = 0;
|
|
Identity *id, *nxt;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshbuf_get_cstring(e->request, &provider, NULL)) != 0 ||
|
|
(r = sshbuf_get_cstring(e->request, &pin, NULL)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto send;
|
|
}
|
|
free(pin);
|
|
|
|
if (realpath(provider, canonical_provider) == NULL) {
|
|
verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
|
|
provider, strerror(errno));
|
|
goto send;
|
|
}
|
|
|
|
debug_f("remove %.100s", canonical_provider);
|
|
for (id = TAILQ_FIRST(&idtab->idlist); id; id = nxt) {
|
|
nxt = TAILQ_NEXT(id, next);
|
|
/* Skip file--based keys */
|
|
if (id->provider == NULL)
|
|
continue;
|
|
if (!strcmp(canonical_provider, id->provider)) {
|
|
TAILQ_REMOVE(&idtab->idlist, id, next);
|
|
free_identity(id);
|
|
idtab->nentries--;
|
|
}
|
|
}
|
|
if (pkcs11_del_provider(canonical_provider) == 0)
|
|
success = 1;
|
|
else
|
|
error_f("pkcs11_del_provider failed");
|
|
send:
|
|
free(provider);
|
|
send_status(e, success);
|
|
}
|
|
#endif /* ENABLE_PKCS11 */
|
|
|
|
static int
|
|
process_ext_session_bind(SocketEntry *e)
|
|
{
|
|
int r, sid_match, key_match;
|
|
struct sshkey *key = NULL;
|
|
struct sshbuf *sid = NULL, *sig = NULL;
|
|
char *fp = NULL;
|
|
size_t i;
|
|
u_char fwd = 0;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshkey_froms(e->request, &key)) != 0 ||
|
|
(r = sshbuf_froms(e->request, &sid)) != 0 ||
|
|
(r = sshbuf_froms(e->request, &sig)) != 0 ||
|
|
(r = sshbuf_get_u8(e->request, &fwd)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto out;
|
|
}
|
|
if ((fp = sshkey_fingerprint(key, SSH_FP_HASH_DEFAULT,
|
|
SSH_FP_DEFAULT)) == NULL)
|
|
fatal_f("fingerprint failed");
|
|
/* check signature with hostkey on session ID */
|
|
if ((r = sshkey_verify(key, sshbuf_ptr(sig), sshbuf_len(sig),
|
|
sshbuf_ptr(sid), sshbuf_len(sid), NULL, 0, NULL)) != 0) {
|
|
error_fr(r, "sshkey_verify for %s %s", sshkey_type(key), fp);
|
|
goto out;
|
|
}
|
|
/* check whether sid/key already recorded */
|
|
for (i = 0; i < e->nsession_ids; i++) {
|
|
if (!e->session_ids[i].forwarded) {
|
|
error_f("attempt to bind session ID to socket "
|
|
"previously bound for authentication attempt");
|
|
r = -1;
|
|
goto out;
|
|
}
|
|
sid_match = buf_equal(sid, e->session_ids[i].sid) == 0;
|
|
key_match = sshkey_equal(key, e->session_ids[i].key);
|
|
if (sid_match && key_match) {
|
|
debug_f("session ID already recorded for %s %s",
|
|
sshkey_type(key), fp);
|
|
r = 0;
|
|
goto out;
|
|
} else if (sid_match) {
|
|
error_f("session ID recorded against different key "
|
|
"for %s %s", sshkey_type(key), fp);
|
|
r = -1;
|
|
goto out;
|
|
}
|
|
/*
|
|
* new sid with previously-seen key can happen, e.g. multiple
|
|
* connections to the same host.
|
|
*/
|
|
}
|
|
/* record new key/sid */
|
|
if (e->nsession_ids >= AGENT_MAX_SESSION_IDS) {
|
|
error_f("too many session IDs recorded");
|
|
goto out;
|
|
}
|
|
e->session_ids = xrecallocarray(e->session_ids, e->nsession_ids,
|
|
e->nsession_ids + 1, sizeof(*e->session_ids));
|
|
i = e->nsession_ids++;
|
|
debug_f("recorded %s %s (slot %zu of %d)", sshkey_type(key), fp, i,
|
|
AGENT_MAX_SESSION_IDS);
|
|
e->session_ids[i].key = key;
|
|
e->session_ids[i].forwarded = fwd != 0;
|
|
key = NULL; /* transferred */
|
|
/* can't transfer sid; it's refcounted and scoped to request's life */
|
|
if ((e->session_ids[i].sid = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new");
|
|
if ((r = sshbuf_putb(e->session_ids[i].sid, sid)) != 0)
|
|
fatal_fr(r, "sshbuf_putb session ID");
|
|
/* success */
|
|
r = 0;
|
|
out:
|
|
free(fp);
|
|
sshkey_free(key);
|
|
sshbuf_free(sid);
|
|
sshbuf_free(sig);
|
|
return r == 0 ? 1 : 0;
|
|
}
|
|
|
|
static void
|
|
process_extension(SocketEntry *e)
|
|
{
|
|
int r, success = 0;
|
|
char *name;
|
|
|
|
debug2_f("entering");
|
|
if ((r = sshbuf_get_cstring(e->request, &name, NULL)) != 0) {
|
|
error_fr(r, "parse");
|
|
goto send;
|
|
}
|
|
if (strcmp(name, "session-bind@openssh.com") == 0)
|
|
success = process_ext_session_bind(e);
|
|
else
|
|
debug_f("unsupported extension \"%s\"", name);
|
|
free(name);
|
|
send:
|
|
send_status(e, success);
|
|
}
|
|
/*
|
|
* dispatch incoming message.
|
|
* returns 1 on success, 0 for incomplete messages or -1 on error.
|
|
*/
|
|
static int
|
|
process_message(u_int socknum)
|
|
{
|
|
u_int msg_len;
|
|
u_char type;
|
|
const u_char *cp;
|
|
int r;
|
|
SocketEntry *e;
|
|
|
|
if (socknum >= sockets_alloc)
|
|
fatal_f("sock %u >= allocated %u", socknum, sockets_alloc);
|
|
e = &sockets[socknum];
|
|
|
|
if (sshbuf_len(e->input) < 5)
|
|
return 0; /* Incomplete message header. */
|
|
cp = sshbuf_ptr(e->input);
|
|
msg_len = PEEK_U32(cp);
|
|
if (msg_len > AGENT_MAX_LEN) {
|
|
debug_f("socket %u (fd=%d) message too long %u > %u",
|
|
socknum, e->fd, msg_len, AGENT_MAX_LEN);
|
|
return -1;
|
|
}
|
|
if (sshbuf_len(e->input) < msg_len + 4)
|
|
return 0; /* Incomplete message body. */
|
|
|
|
/* move the current input to e->request */
|
|
sshbuf_reset(e->request);
|
|
if ((r = sshbuf_get_stringb(e->input, e->request)) != 0 ||
|
|
(r = sshbuf_get_u8(e->request, &type)) != 0) {
|
|
if (r == SSH_ERR_MESSAGE_INCOMPLETE ||
|
|
r == SSH_ERR_STRING_TOO_LARGE) {
|
|
error_fr(r, "parse");
|
|
return -1;
|
|
}
|
|
fatal_fr(r, "parse");
|
|
}
|
|
|
|
debug_f("socket %u (fd=%d) type %d", socknum, e->fd, type);
|
|
|
|
/* check whether agent is locked */
|
|
if (locked && type != SSH_AGENTC_UNLOCK) {
|
|
sshbuf_reset(e->request);
|
|
switch (type) {
|
|
case SSH2_AGENTC_REQUEST_IDENTITIES:
|
|
/* send empty lists */
|
|
no_identities(e);
|
|
break;
|
|
default:
|
|
/* send a fail message for all other request types */
|
|
send_status(e, 0);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
switch (type) {
|
|
case SSH_AGENTC_LOCK:
|
|
case SSH_AGENTC_UNLOCK:
|
|
process_lock_agent(e, type == SSH_AGENTC_LOCK);
|
|
break;
|
|
case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES:
|
|
process_remove_all_identities(e); /* safe for !WITH_SSH1 */
|
|
break;
|
|
/* ssh2 */
|
|
case SSH2_AGENTC_SIGN_REQUEST:
|
|
process_sign_request2(e);
|
|
break;
|
|
case SSH2_AGENTC_REQUEST_IDENTITIES:
|
|
process_request_identities(e);
|
|
break;
|
|
case SSH2_AGENTC_ADD_IDENTITY:
|
|
case SSH2_AGENTC_ADD_ID_CONSTRAINED:
|
|
process_add_identity(e);
|
|
break;
|
|
case SSH2_AGENTC_REMOVE_IDENTITY:
|
|
process_remove_identity(e);
|
|
break;
|
|
case SSH2_AGENTC_REMOVE_ALL_IDENTITIES:
|
|
process_remove_all_identities(e);
|
|
break;
|
|
#ifdef ENABLE_PKCS11
|
|
case SSH_AGENTC_ADD_SMARTCARD_KEY:
|
|
case SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED:
|
|
process_add_smartcard_key(e);
|
|
break;
|
|
case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
|
|
process_remove_smartcard_key(e);
|
|
break;
|
|
#endif /* ENABLE_PKCS11 */
|
|
case SSH_AGENTC_EXTENSION:
|
|
process_extension(e);
|
|
break;
|
|
default:
|
|
/* Unknown message. Respond with failure. */
|
|
error("Unknown message %d", type);
|
|
sshbuf_reset(e->request);
|
|
send_status(e, 0);
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static void
|
|
new_socket(sock_type type, int fd)
|
|
{
|
|
u_int i, old_alloc, new_alloc;
|
|
|
|
debug_f("type = %s", type == AUTH_CONNECTION ? "CONNECTION" :
|
|
(type == AUTH_SOCKET ? "SOCKET" : "UNKNOWN"));
|
|
if (type == AUTH_CONNECTION) {
|
|
debug("xcount %d -> %d", xcount, xcount + 1);
|
|
++xcount;
|
|
}
|
|
set_nonblock(fd);
|
|
|
|
if (fd > max_fd)
|
|
max_fd = fd;
|
|
|
|
for (i = 0; i < sockets_alloc; i++)
|
|
if (sockets[i].type == AUTH_UNUSED) {
|
|
sockets[i].fd = fd;
|
|
if ((sockets[i].input = sshbuf_new()) == NULL ||
|
|
(sockets[i].output = sshbuf_new()) == NULL ||
|
|
(sockets[i].request = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
sockets[i].type = type;
|
|
return;
|
|
}
|
|
old_alloc = sockets_alloc;
|
|
new_alloc = sockets_alloc + 10;
|
|
sockets = xrecallocarray(sockets, old_alloc, new_alloc,
|
|
sizeof(sockets[0]));
|
|
for (i = old_alloc; i < new_alloc; i++)
|
|
sockets[i].type = AUTH_UNUSED;
|
|
sockets_alloc = new_alloc;
|
|
sockets[old_alloc].fd = fd;
|
|
if ((sockets[old_alloc].input = sshbuf_new()) == NULL ||
|
|
(sockets[old_alloc].output = sshbuf_new()) == NULL ||
|
|
(sockets[old_alloc].request = sshbuf_new()) == NULL)
|
|
fatal_f("sshbuf_new failed");
|
|
sockets[old_alloc].type = type;
|
|
}
|
|
|
|
static int
|
|
handle_socket_read(u_int socknum)
|
|
{
|
|
struct sockaddr_un sunaddr;
|
|
socklen_t slen;
|
|
uid_t euid;
|
|
gid_t egid;
|
|
int fd;
|
|
|
|
slen = sizeof(sunaddr);
|
|
fd = accept(sockets[socknum].fd, (struct sockaddr *)&sunaddr, &slen);
|
|
if (fd == -1) {
|
|
error("accept from AUTH_SOCKET: %s", strerror(errno));
|
|
return -1;
|
|
}
|
|
if (getpeereid(fd, &euid, &egid) == -1) {
|
|
error("getpeereid %d failed: %s", fd, strerror(errno));
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
if ((euid != 0) && (getuid() != euid)) {
|
|
error("uid mismatch: peer euid %u != uid %u",
|
|
(u_int) euid, (u_int) getuid());
|
|
close(fd);
|
|
return -1;
|
|
}
|
|
new_socket(AUTH_CONNECTION, fd);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
handle_conn_read(u_int socknum)
|
|
{
|
|
char buf[AGENT_RBUF_LEN];
|
|
ssize_t len;
|
|
int r;
|
|
|
|
if ((len = read(sockets[socknum].fd, buf, sizeof(buf))) <= 0) {
|
|
if (len == -1) {
|
|
if (errno == EAGAIN || errno == EINTR)
|
|
return 0;
|
|
error_f("read error on socket %u (fd %d): %s",
|
|
socknum, sockets[socknum].fd, strerror(errno));
|
|
}
|
|
return -1;
|
|
}
|
|
if ((r = sshbuf_put(sockets[socknum].input, buf, len)) != 0)
|
|
fatal_fr(r, "compose");
|
|
explicit_bzero(buf, sizeof(buf));
|
|
for (;;) {
|
|
if ((r = process_message(socknum)) == -1)
|
|
return -1;
|
|
else if (r == 0)
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
handle_conn_write(u_int socknum)
|
|
{
|
|
ssize_t len;
|
|
int r;
|
|
|
|
if (sshbuf_len(sockets[socknum].output) == 0)
|
|
return 0; /* shouldn't happen */
|
|
if ((len = write(sockets[socknum].fd,
|
|
sshbuf_ptr(sockets[socknum].output),
|
|
sshbuf_len(sockets[socknum].output))) <= 0) {
|
|
if (len == -1) {
|
|
if (errno == EAGAIN || errno == EINTR)
|
|
return 0;
|
|
error_f("read error on socket %u (fd %d): %s",
|
|
socknum, sockets[socknum].fd, strerror(errno));
|
|
}
|
|
return -1;
|
|
}
|
|
if ((r = sshbuf_consume(sockets[socknum].output, len)) != 0)
|
|
fatal_fr(r, "consume");
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
after_poll(struct pollfd *pfd, size_t npfd, u_int maxfds)
|
|
{
|
|
size_t i;
|
|
u_int socknum, activefds = npfd;
|
|
|
|
for (i = 0; i < npfd; i++) {
|
|
if (pfd[i].revents == 0)
|
|
continue;
|
|
/* Find sockets entry */
|
|
for (socknum = 0; socknum < sockets_alloc; socknum++) {
|
|
if (sockets[socknum].type != AUTH_SOCKET &&
|
|
sockets[socknum].type != AUTH_CONNECTION)
|
|
continue;
|
|
if (pfd[i].fd == sockets[socknum].fd)
|
|
break;
|
|
}
|
|
if (socknum >= sockets_alloc) {
|
|
error_f("no socket for fd %d", pfd[i].fd);
|
|
continue;
|
|
}
|
|
/* Process events */
|
|
switch (sockets[socknum].type) {
|
|
case AUTH_SOCKET:
|
|
if ((pfd[i].revents & (POLLIN|POLLERR)) == 0)
|
|
break;
|
|
if (npfd > maxfds) {
|
|
debug3("out of fds (active %u >= limit %u); "
|
|
"skipping accept", activefds, maxfds);
|
|
break;
|
|
}
|
|
if (handle_socket_read(socknum) == 0)
|
|
activefds++;
|
|
break;
|
|
case AUTH_CONNECTION:
|
|
if ((pfd[i].revents & (POLLIN|POLLHUP|POLLERR)) != 0 &&
|
|
handle_conn_read(socknum) != 0)
|
|
goto close_sock;
|
|
if ((pfd[i].revents & (POLLOUT|POLLHUP)) != 0 &&
|
|
handle_conn_write(socknum) != 0) {
|
|
close_sock:
|
|
if (activefds == 0)
|
|
fatal("activefds == 0 at close_sock");
|
|
close_socket(&sockets[socknum]);
|
|
activefds--;
|
|
break;
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static int
|
|
prepare_poll(struct pollfd **pfdp, size_t *npfdp, int *timeoutp, u_int maxfds)
|
|
{
|
|
struct pollfd *pfd = *pfdp;
|
|
size_t i, j, npfd = 0;
|
|
time_t deadline;
|
|
int r;
|
|
|
|
/* Count active sockets */
|
|
for (i = 0; i < sockets_alloc; i++) {
|
|
switch (sockets[i].type) {
|
|
case AUTH_SOCKET:
|
|
case AUTH_CONNECTION:
|
|
npfd++;
|
|
break;
|
|
case AUTH_UNUSED:
|
|
break;
|
|
default:
|
|
fatal("Unknown socket type %d", sockets[i].type);
|
|
break;
|
|
}
|
|
}
|
|
if (npfd != *npfdp &&
|
|
(pfd = recallocarray(pfd, *npfdp, npfd, sizeof(*pfd))) == NULL)
|
|
fatal_f("recallocarray failed");
|
|
*pfdp = pfd;
|
|
*npfdp = npfd;
|
|
|
|
for (i = j = 0; i < sockets_alloc; i++) {
|
|
switch (sockets[i].type) {
|
|
case AUTH_SOCKET:
|
|
if (npfd > maxfds) {
|
|
debug3("out of fds (active %zu >= limit %u); "
|
|
"skipping arming listener", npfd, maxfds);
|
|
break;
|
|
}
|
|
pfd[j].fd = sockets[i].fd;
|
|
pfd[j].revents = 0;
|
|
pfd[j].events = POLLIN;
|
|
j++;
|
|
break;
|
|
case AUTH_CONNECTION:
|
|
pfd[j].fd = sockets[i].fd;
|
|
pfd[j].revents = 0;
|
|
/*
|
|
* Only prepare to read if we can handle a full-size
|
|
* input read buffer and enqueue a max size reply..
|
|
*/
|
|
if ((r = sshbuf_check_reserve(sockets[i].input,
|
|
AGENT_RBUF_LEN)) == 0 &&
|
|
(r = sshbuf_check_reserve(sockets[i].output,
|
|
AGENT_MAX_LEN)) == 0)
|
|
pfd[j].events = POLLIN;
|
|
else if (r != SSH_ERR_NO_BUFFER_SPACE)
|
|
fatal_fr(r, "reserve");
|
|
if (sshbuf_len(sockets[i].output) > 0)
|
|
pfd[j].events |= POLLOUT;
|
|
j++;
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
deadline = reaper();
|
|
if (parent_alive_interval != 0)
|
|
deadline = (deadline == 0) ? parent_alive_interval :
|
|
MINIMUM(deadline, parent_alive_interval);
|
|
if (deadline == 0) {
|
|
*timeoutp = -1; /* INFTIM */
|
|
} else {
|
|
if (deadline > INT_MAX / 1000)
|
|
*timeoutp = INT_MAX / 1000;
|
|
else
|
|
*timeoutp = deadline * 1000;
|
|
}
|
|
return (1);
|
|
}
|
|
|
|
static void
|
|
cleanup_socket(void)
|
|
{
|
|
if (cleanup_pid != 0 && getpid() != cleanup_pid)
|
|
return;
|
|
debug_f("cleanup");
|
|
if (socket_name[0])
|
|
unlink(socket_name);
|
|
if (socket_dir[0])
|
|
rmdir(socket_dir);
|
|
}
|
|
|
|
void
|
|
cleanup_exit(int i)
|
|
{
|
|
cleanup_socket();
|
|
_exit(i);
|
|
}
|
|
|
|
static void
|
|
cleanup_handler(int sig)
|
|
{
|
|
cleanup_socket();
|
|
#ifdef ENABLE_PKCS11
|
|
pkcs11_terminate();
|
|
#endif
|
|
_exit(2);
|
|
}
|
|
|
|
static void
|
|
check_parent_exists(void)
|
|
{
|
|
/*
|
|
* If our parent has exited then getppid() will return (pid_t)1,
|
|
* so testing for that should be safe.
|
|
*/
|
|
if (parent_pid != -1 && getppid() != parent_pid) {
|
|
/* printf("Parent has died - Authentication agent exiting.\n"); */
|
|
cleanup_socket();
|
|
_exit(2);
|
|
}
|
|
}
|
|
|
|
static void
|
|
usage(void)
|
|
{
|
|
fprintf(stderr,
|
|
"usage: ssh-agent [-c | -s] [-Ddx] [-a bind_address] [-E fingerprint_hash]\n"
|
|
" [-O option] [-P allowed_providers] [-t life]\n"
|
|
" ssh-agent [-a bind_address] [-E fingerprint_hash] [-O option]\n"
|
|
" [-P allowed_providers] [-t life] command [arg ...]\n"
|
|
" ssh-agent [-c | -s] -k\n");
|
|
exit(1);
|
|
}
|
|
|
|
int
|
|
main(int ac, char **av)
|
|
{
|
|
int c_flag = 0, d_flag = 0, D_flag = 0, k_flag = 0, s_flag = 0;
|
|
int sock, ch, result, saved_errno;
|
|
char *shell, *format, *pidstr, *agentsocket = NULL;
|
|
#ifdef HAVE_SETRLIMIT
|
|
struct rlimit rlim;
|
|
#endif
|
|
extern int optind;
|
|
extern char *optarg;
|
|
pid_t pid;
|
|
char pidstrbuf[1 + 3 * sizeof pid];
|
|
size_t len;
|
|
mode_t prev_mask;
|
|
int timeout = -1; /* INFTIM */
|
|
struct pollfd *pfd = NULL;
|
|
size_t npfd = 0;
|
|
u_int maxfds;
|
|
|
|
/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
|
|
sanitise_stdfd();
|
|
|
|
/* drop */
|
|
setegid(getgid());
|
|
setgid(getgid());
|
|
setuid(geteuid());
|
|
|
|
platform_disable_tracing(0); /* strict=no */
|
|
|
|
#ifdef RLIMIT_NOFILE
|
|
if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
|
|
fatal("%s: getrlimit: %s", __progname, strerror(errno));
|
|
#endif
|
|
|
|
__progname = ssh_get_progname(av[0]);
|
|
seed_rng();
|
|
|
|
while ((ch = getopt(ac, av, "cDdksE:a:O:P:t:x")) != -1) {
|
|
switch (ch) {
|
|
case 'E':
|
|
fingerprint_hash = ssh_digest_alg_by_name(optarg);
|
|
if (fingerprint_hash == -1)
|
|
fatal("Invalid hash algorithm \"%s\"", optarg);
|
|
break;
|
|
case 'c':
|
|
if (s_flag)
|
|
usage();
|
|
c_flag++;
|
|
break;
|
|
case 'k':
|
|
k_flag++;
|
|
break;
|
|
case 'O':
|
|
if (strcmp(optarg, "no-restrict-websafe") == 0)
|
|
restrict_websafe = 0;
|
|
else
|
|
fatal("Unknown -O option");
|
|
break;
|
|
case 'P':
|
|
if (allowed_providers != NULL)
|
|
fatal("-P option already specified");
|
|
allowed_providers = xstrdup(optarg);
|
|
break;
|
|
case 's':
|
|
if (c_flag)
|
|
usage();
|
|
s_flag++;
|
|
break;
|
|
case 'd':
|
|
if (d_flag || D_flag)
|
|
usage();
|
|
d_flag++;
|
|
break;
|
|
case 'D':
|
|
if (d_flag || D_flag)
|
|
usage();
|
|
D_flag++;
|
|
break;
|
|
case 'a':
|
|
agentsocket = optarg;
|
|
break;
|
|
case 't':
|
|
if ((lifetime = convtime(optarg)) == -1) {
|
|
fprintf(stderr, "Invalid lifetime\n");
|
|
usage();
|
|
}
|
|
break;
|
|
case 'x':
|
|
xcount = 0;
|
|
break;
|
|
default:
|
|
usage();
|
|
}
|
|
}
|
|
ac -= optind;
|
|
av += optind;
|
|
|
|
if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
|
|
usage();
|
|
|
|
if (allowed_providers == NULL)
|
|
allowed_providers = xstrdup(DEFAULT_ALLOWED_PROVIDERS);
|
|
|
|
if (ac == 0 && !c_flag && !s_flag) {
|
|
shell = getenv("SHELL");
|
|
if (shell != NULL && (len = strlen(shell)) > 2 &&
|
|
strncmp(shell + len - 3, "csh", 3) == 0)
|
|
c_flag = 1;
|
|
}
|
|
if (k_flag) {
|
|
const char *errstr = NULL;
|
|
|
|
pidstr = getenv(SSH_AGENTPID_ENV_NAME);
|
|
if (pidstr == NULL) {
|
|
fprintf(stderr, "%s not set, cannot kill agent\n",
|
|
SSH_AGENTPID_ENV_NAME);
|
|
exit(1);
|
|
}
|
|
pid = (int)strtonum(pidstr, 2, INT_MAX, &errstr);
|
|
if (errstr) {
|
|
fprintf(stderr,
|
|
"%s=\"%s\", which is not a good PID: %s\n",
|
|
SSH_AGENTPID_ENV_NAME, pidstr, errstr);
|
|
exit(1);
|
|
}
|
|
if (kill(pid, SIGTERM) == -1) {
|
|
perror("kill");
|
|
exit(1);
|
|
}
|
|
format = c_flag ? "unsetenv %s;\n" : "unset %s;\n";
|
|
printf(format, SSH_AUTHSOCKET_ENV_NAME);
|
|
printf(format, SSH_AGENTPID_ENV_NAME);
|
|
printf("echo Agent pid %ld killed;\n", (long)pid);
|
|
exit(0);
|
|
}
|
|
|
|
/*
|
|
* Minimum file descriptors:
|
|
* stdio (3) + listener (1) + syslog (1 maybe) + connection (1) +
|
|
* a few spare for libc / stack protectors / sanitisers, etc.
|
|
*/
|
|
#define SSH_AGENT_MIN_FDS (3+1+1+1+4)
|
|
if (rlim.rlim_cur < SSH_AGENT_MIN_FDS)
|
|
fatal("%s: file descriptor rlimit %lld too low (minimum %u)",
|
|
__progname, (long long)rlim.rlim_cur, SSH_AGENT_MIN_FDS);
|
|
maxfds = rlim.rlim_cur - SSH_AGENT_MIN_FDS;
|
|
|
|
parent_pid = getpid();
|
|
|
|
if (agentsocket == NULL) {
|
|
/* Create private directory for agent socket */
|
|
mktemp_proto(socket_dir, sizeof(socket_dir));
|
|
if (mkdtemp(socket_dir) == NULL) {
|
|
perror("mkdtemp: private socket dir");
|
|
exit(1);
|
|
}
|
|
snprintf(socket_name, sizeof socket_name, "%s/agent.%ld", socket_dir,
|
|
(long)parent_pid);
|
|
} else {
|
|
/* Try to use specified agent socket */
|
|
socket_dir[0] = '\0';
|
|
strlcpy(socket_name, agentsocket, sizeof socket_name);
|
|
}
|
|
|
|
/*
|
|
* Create socket early so it will exist before command gets run from
|
|
* the parent.
|
|
*/
|
|
prev_mask = umask(0177);
|
|
sock = unix_listener(socket_name, SSH_LISTEN_BACKLOG, 0);
|
|
if (sock < 0) {
|
|
/* XXX - unix_listener() calls error() not perror() */
|
|
*socket_name = '\0'; /* Don't unlink any existing file */
|
|
cleanup_exit(1);
|
|
}
|
|
umask(prev_mask);
|
|
|
|
/*
|
|
* Fork, and have the parent execute the command, if any, or present
|
|
* the socket data. The child continues as the authentication agent.
|
|
*/
|
|
if (D_flag || d_flag) {
|
|
log_init(__progname,
|
|
d_flag ? SYSLOG_LEVEL_DEBUG3 : SYSLOG_LEVEL_INFO,
|
|
SYSLOG_FACILITY_AUTH, 1);
|
|
format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
|
|
printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
|
|
SSH_AUTHSOCKET_ENV_NAME);
|
|
printf("echo Agent pid %ld;\n", (long)parent_pid);
|
|
fflush(stdout);
|
|
goto skip;
|
|
}
|
|
pid = fork();
|
|
if (pid == -1) {
|
|
perror("fork");
|
|
cleanup_exit(1);
|
|
}
|
|
if (pid != 0) { /* Parent - execute the given command. */
|
|
close(sock);
|
|
snprintf(pidstrbuf, sizeof pidstrbuf, "%ld", (long)pid);
|
|
if (ac == 0) {
|
|
format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n";
|
|
printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name,
|
|
SSH_AUTHSOCKET_ENV_NAME);
|
|
printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf,
|
|
SSH_AGENTPID_ENV_NAME);
|
|
printf("echo Agent pid %ld;\n", (long)pid);
|
|
exit(0);
|
|
}
|
|
if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 ||
|
|
setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) {
|
|
perror("setenv");
|
|
exit(1);
|
|
}
|
|
execvp(av[0], av);
|
|
perror(av[0]);
|
|
exit(1);
|
|
}
|
|
/* child */
|
|
log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0);
|
|
|
|
if (setsid() == -1) {
|
|
error("setsid: %s", strerror(errno));
|
|
cleanup_exit(1);
|
|
}
|
|
|
|
(void)chdir("/");
|
|
if (stdfd_devnull(1, 1, 1) == -1)
|
|
error_f("stdfd_devnull failed");
|
|
|
|
#ifdef HAVE_SETRLIMIT
|
|
/* deny core dumps, since memory contains unencrypted private keys */
|
|
rlim.rlim_cur = rlim.rlim_max = 0;
|
|
if (setrlimit(RLIMIT_CORE, &rlim) == -1) {
|
|
error("setrlimit RLIMIT_CORE: %s", strerror(errno));
|
|
cleanup_exit(1);
|
|
}
|
|
#endif
|
|
|
|
skip:
|
|
|
|
cleanup_pid = getpid();
|
|
|
|
#ifdef ENABLE_PKCS11
|
|
pkcs11_init(0);
|
|
#endif
|
|
new_socket(AUTH_SOCKET, sock);
|
|
if (ac > 0)
|
|
parent_alive_interval = 10;
|
|
idtab_init();
|
|
ssh_signal(SIGPIPE, SIG_IGN);
|
|
ssh_signal(SIGINT, (d_flag | D_flag) ? cleanup_handler : SIG_IGN);
|
|
ssh_signal(SIGHUP, cleanup_handler);
|
|
ssh_signal(SIGTERM, cleanup_handler);
|
|
|
|
if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
|
|
fatal("%s: pledge: %s", __progname, strerror(errno));
|
|
platform_pledge_agent();
|
|
|
|
while (1) {
|
|
prepare_poll(&pfd, &npfd, &timeout, maxfds);
|
|
result = poll(pfd, npfd, timeout);
|
|
saved_errno = errno;
|
|
if (parent_alive_interval != 0)
|
|
check_parent_exists();
|
|
(void) reaper(); /* remove expired keys */
|
|
if (result == -1) {
|
|
if (saved_errno == EINTR)
|
|
continue;
|
|
fatal("poll: %s", strerror(saved_errno));
|
|
} else if (result > 0)
|
|
after_poll(pfd, npfd, maxfds);
|
|
}
|
|
/* NOTREACHED */
|
|
}
|