Release notes are available at https://www.openssh.com/txt/release-8.9 Some highlights: * ssh(1), sshd(8), ssh-add(1), ssh-agent(1): add a system for restricting forwarding and use of keys added to ssh-agent(1) * ssh(1), sshd(8): add the sntrup761x25519-sha512@openssh.com hybrid ECDH/x25519 + Streamlined NTRU Prime post-quantum KEX to the default KEXAlgorithms list (after the ECDH methods but before the prime-group DH ones). The next release of OpenSSH is likely to make this key exchange the default method. * sshd(8), portable OpenSSH only: this release removes in-built support for MD5-hashed passwords. If you require these on your system then we recommend linking against libxcrypt or similar. Future deprecation notice ========================= A near-future release of OpenSSH will switch scp(1) from using the legacy scp/rcp protocol to using SFTP by default. Legacy scp/rcp performs wildcard expansion of remote filenames (e.g. "scp host:* .") through the remote shell. This has the side effect of requiring double quoting of shell meta-characters in file names included on scp(1) command-lines, otherwise they could be interpreted as shell commands on the remote side. MFC after: 1 month Relnotes: Yes Sponsored by: The FreeBSD Foundation
392 lines
9.6 KiB
C
392 lines
9.6 KiB
C
/* $OpenBSD: ssh-pkcs11-client.c,v 1.17 2020/10/18 11:32:02 djm Exp $ */
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/*
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* Copyright (c) 2010 Markus Friedl. All rights reserved.
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* Copyright (c) 2014 Pedro Martelletto. All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#ifdef ENABLE_PKCS11
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#include <sys/types.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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#include <sys/socket.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 <errno.h>
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#include <openssl/ecdsa.h>
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#include <openssl/rsa.h>
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#include "openbsd-compat/openssl-compat.h"
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#include "pathnames.h"
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#include "xmalloc.h"
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#include "sshbuf.h"
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#include "log.h"
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#include "misc.h"
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#include "sshkey.h"
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#include "authfd.h"
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#include "atomicio.h"
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#include "ssh-pkcs11.h"
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#include "ssherr.h"
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/* borrows code from sftp-server and ssh-agent */
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static int fd = -1;
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static pid_t pid = -1;
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static void
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send_msg(struct sshbuf *m)
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{
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u_char buf[4];
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size_t mlen = sshbuf_len(m);
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int r;
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POKE_U32(buf, mlen);
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if (atomicio(vwrite, fd, buf, 4) != 4 ||
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atomicio(vwrite, fd, sshbuf_mutable_ptr(m),
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sshbuf_len(m)) != sshbuf_len(m))
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error("write to helper failed");
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if ((r = sshbuf_consume(m, mlen)) != 0)
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fatal_fr(r, "consume");
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}
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static int
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recv_msg(struct sshbuf *m)
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{
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u_int l, len;
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u_char c, buf[1024];
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int r;
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if ((len = atomicio(read, fd, buf, 4)) != 4) {
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error("read from helper failed: %u", len);
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return (0); /* XXX */
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}
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len = PEEK_U32(buf);
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if (len > 256 * 1024)
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fatal("response too long: %u", len);
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/* read len bytes into m */
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sshbuf_reset(m);
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while (len > 0) {
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l = len;
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if (l > sizeof(buf))
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l = sizeof(buf);
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if (atomicio(read, fd, buf, l) != l) {
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error("response from helper failed.");
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return (0); /* XXX */
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}
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if ((r = sshbuf_put(m, buf, l)) != 0)
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fatal_fr(r, "sshbuf_put");
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len -= l;
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}
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if ((r = sshbuf_get_u8(m, &c)) != 0)
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fatal_fr(r, "parse type");
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return c;
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}
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int
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pkcs11_init(int interactive)
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{
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return (0);
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}
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void
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pkcs11_terminate(void)
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{
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if (fd >= 0)
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close(fd);
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}
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static int
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rsa_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, int padding)
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{
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struct sshkey *key = NULL;
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struct sshbuf *msg = NULL;
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u_char *blob = NULL, *signature = NULL;
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size_t blen, slen = 0;
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int r, ret = -1;
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if (padding != RSA_PKCS1_PADDING)
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goto fail;
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key = sshkey_new(KEY_UNSPEC);
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if (key == NULL) {
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error_f("sshkey_new failed");
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goto fail;
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}
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key->type = KEY_RSA;
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RSA_up_ref(rsa);
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key->rsa = rsa;
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if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
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error_fr(r, "encode key");
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goto fail;
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}
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if ((msg = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
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(r = sshbuf_put_string(msg, blob, blen)) != 0 ||
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(r = sshbuf_put_string(msg, from, flen)) != 0 ||
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(r = sshbuf_put_u32(msg, 0)) != 0)
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fatal_fr(r, "compose");
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send_msg(msg);
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sshbuf_reset(msg);
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if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
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if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
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fatal_fr(r, "parse");
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if (slen <= (size_t)RSA_size(rsa)) {
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memcpy(to, signature, slen);
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ret = slen;
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}
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free(signature);
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}
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fail:
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free(blob);
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sshkey_free(key);
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sshbuf_free(msg);
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return (ret);
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}
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#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
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static ECDSA_SIG *
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ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
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const BIGNUM *rp, EC_KEY *ec)
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{
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struct sshkey *key = NULL;
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struct sshbuf *msg = NULL;
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ECDSA_SIG *ret = NULL;
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const u_char *cp;
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u_char *blob = NULL, *signature = NULL;
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size_t blen, slen = 0;
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int r, nid;
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nid = sshkey_ecdsa_key_to_nid(ec);
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if (nid < 0) {
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error_f("couldn't get curve nid");
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goto fail;
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}
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key = sshkey_new(KEY_UNSPEC);
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if (key == NULL) {
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error_f("sshkey_new failed");
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goto fail;
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}
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key->ecdsa = ec;
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key->ecdsa_nid = nid;
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key->type = KEY_ECDSA;
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EC_KEY_up_ref(ec);
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if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
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error_fr(r, "encode key");
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goto fail;
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}
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if ((msg = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
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(r = sshbuf_put_string(msg, blob, blen)) != 0 ||
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(r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
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(r = sshbuf_put_u32(msg, 0)) != 0)
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fatal_fr(r, "compose");
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send_msg(msg);
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sshbuf_reset(msg);
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if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
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if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
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fatal_fr(r, "parse");
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cp = signature;
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ret = d2i_ECDSA_SIG(NULL, &cp, slen);
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free(signature);
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}
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fail:
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free(blob);
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sshkey_free(key);
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sshbuf_free(msg);
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return (ret);
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}
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#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
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static RSA_METHOD *helper_rsa;
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#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
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static EC_KEY_METHOD *helper_ecdsa;
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#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
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/* redirect private key crypto operations to the ssh-pkcs11-helper */
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static void
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wrap_key(struct sshkey *k)
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{
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if (k->type == KEY_RSA)
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RSA_set_method(k->rsa, helper_rsa);
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#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
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else if (k->type == KEY_ECDSA)
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EC_KEY_set_method(k->ecdsa, helper_ecdsa);
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#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
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else
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fatal_f("unknown key type");
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}
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static int
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pkcs11_start_helper_methods(void)
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{
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if (helper_rsa != NULL)
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return (0);
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#if defined(OPENSSL_HAS_ECC) && defined(HAVE_EC_KEY_METHOD_NEW)
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int (*orig_sign)(int, const unsigned char *, int, unsigned char *,
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unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
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if (helper_ecdsa != NULL)
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return (0);
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helper_ecdsa = EC_KEY_METHOD_new(EC_KEY_OpenSSL());
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if (helper_ecdsa == NULL)
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return (-1);
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EC_KEY_METHOD_get_sign(helper_ecdsa, &orig_sign, NULL, NULL);
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EC_KEY_METHOD_set_sign(helper_ecdsa, orig_sign, NULL, ecdsa_do_sign);
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#endif /* OPENSSL_HAS_ECC && HAVE_EC_KEY_METHOD_NEW */
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if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL)
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fatal_f("RSA_meth_dup failed");
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if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") ||
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!RSA_meth_set_priv_enc(helper_rsa, rsa_encrypt))
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fatal_f("failed to prepare method");
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return (0);
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}
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static int
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pkcs11_start_helper(void)
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{
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int pair[2];
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char *helper, *verbosity = NULL;
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if (log_level_get() >= SYSLOG_LEVEL_DEBUG1)
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verbosity = "-vvv";
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if (pkcs11_start_helper_methods() == -1) {
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error("pkcs11_start_helper_methods failed");
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return (-1);
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}
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if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
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error("socketpair: %s", strerror(errno));
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return (-1);
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}
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if ((pid = fork()) == -1) {
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error("fork: %s", strerror(errno));
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return (-1);
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} else if (pid == 0) {
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if ((dup2(pair[1], STDIN_FILENO) == -1) ||
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(dup2(pair[1], STDOUT_FILENO) == -1)) {
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fprintf(stderr, "dup2: %s\n", strerror(errno));
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_exit(1);
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}
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close(pair[0]);
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close(pair[1]);
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helper = getenv("SSH_PKCS11_HELPER");
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if (helper == NULL || strlen(helper) == 0)
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helper = _PATH_SSH_PKCS11_HELPER;
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debug_f("starting %s %s", helper,
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verbosity == NULL ? "" : verbosity);
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execlp(helper, helper, verbosity, (char *)NULL);
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fprintf(stderr, "exec: %s: %s\n", helper, strerror(errno));
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_exit(1);
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}
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close(pair[1]);
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fd = pair[0];
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return (0);
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}
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int
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pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp,
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char ***labelsp)
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{
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struct sshkey *k;
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int r, type;
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u_char *blob;
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char *label;
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size_t blen;
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u_int nkeys, i;
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struct sshbuf *msg;
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if (fd < 0 && pkcs11_start_helper() < 0)
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return (-1);
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if ((msg = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 ||
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(r = sshbuf_put_cstring(msg, name)) != 0 ||
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(r = sshbuf_put_cstring(msg, pin)) != 0)
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fatal_fr(r, "compose");
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send_msg(msg);
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sshbuf_reset(msg);
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type = recv_msg(msg);
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if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
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if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
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fatal_fr(r, "parse nkeys");
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*keysp = xcalloc(nkeys, sizeof(struct sshkey *));
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if (labelsp)
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*labelsp = xcalloc(nkeys, sizeof(char *));
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for (i = 0; i < nkeys; i++) {
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/* XXX clean up properly instead of fatal() */
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if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 ||
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(r = sshbuf_get_cstring(msg, &label, NULL)) != 0)
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fatal_fr(r, "parse key");
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if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
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fatal_fr(r, "decode key");
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wrap_key(k);
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(*keysp)[i] = k;
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if (labelsp)
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(*labelsp)[i] = label;
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else
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free(label);
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free(blob);
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}
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} else if (type == SSH2_AGENT_FAILURE) {
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if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
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nkeys = -1;
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} else {
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nkeys = -1;
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}
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sshbuf_free(msg);
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return (nkeys);
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}
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int
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pkcs11_del_provider(char *name)
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{
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int r, ret = -1;
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struct sshbuf *msg;
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if ((msg = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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if ((r = sshbuf_put_u8(msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY)) != 0 ||
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(r = sshbuf_put_cstring(msg, name)) != 0 ||
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(r = sshbuf_put_cstring(msg, "")) != 0)
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fatal_fr(r, "compose");
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send_msg(msg);
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sshbuf_reset(msg);
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if (recv_msg(msg) == SSH_AGENT_SUCCESS)
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ret = 0;
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sshbuf_free(msg);
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return (ret);
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}
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#endif /* ENABLE_PKCS11 */
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