| /* $OpenBSD: ssh-pkcs11-client.c,v 1.9 2018/07/09 20:39:28 markus Exp $ */ |
| /* |
| * Copyright (c) 2010 Markus Friedl. All rights reserved. |
| * |
| * Permission to use, copy, modify, and distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| */ |
| |
| #include "includes.h" |
| |
| #ifdef ENABLE_PKCS11 |
| |
| #include <sys/types.h> |
| #ifdef HAVE_SYS_TIME_H |
| # include <sys/time.h> |
| #endif |
| #include <sys/socket.h> |
| |
| #include <stdarg.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <errno.h> |
| |
| #include <openssl/rsa.h> |
| |
| #include "pathnames.h" |
| #include "xmalloc.h" |
| #include "sshbuf.h" |
| #include "log.h" |
| #include "misc.h" |
| #include "sshkey.h" |
| #include "authfd.h" |
| #include "atomicio.h" |
| #include "ssh-pkcs11.h" |
| #include "ssherr.h" |
| |
| /* borrows code from sftp-server and ssh-agent */ |
| |
| int fd = -1; |
| pid_t pid = -1; |
| |
| static void |
| send_msg(struct sshbuf *m) |
| { |
| u_char buf[4]; |
| size_t mlen = sshbuf_len(m); |
| int r; |
| |
| POKE_U32(buf, mlen); |
| if (atomicio(vwrite, fd, buf, 4) != 4 || |
| atomicio(vwrite, fd, (u_char *)sshbuf_ptr(m), |
| sshbuf_len(m)) != sshbuf_len(m)) |
| error("write to helper failed"); |
| if ((r = sshbuf_consume(m, mlen)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| } |
| |
| static int |
| recv_msg(struct sshbuf *m) |
| { |
| u_int l, len; |
| u_char c, buf[1024]; |
| int r; |
| |
| if ((len = atomicio(read, fd, buf, 4)) != 4) { |
| error("read from helper failed: %u", len); |
| return (0); /* XXX */ |
| } |
| len = PEEK_U32(buf); |
| if (len > 256 * 1024) |
| fatal("response too long: %u", len); |
| /* read len bytes into m */ |
| sshbuf_reset(m); |
| while (len > 0) { |
| l = len; |
| if (l > sizeof(buf)) |
| l = sizeof(buf); |
| if (atomicio(read, fd, buf, l) != l) { |
| error("response from helper failed."); |
| return (0); /* XXX */ |
| } |
| if ((r = sshbuf_put(m, buf, l)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| len -= l; |
| } |
| if ((r = sshbuf_get_u8(m, &c)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| return c; |
| } |
| |
| int |
| pkcs11_init(int interactive) |
| { |
| return (0); |
| } |
| |
| void |
| pkcs11_terminate(void) |
| { |
| if (fd >= 0) |
| close(fd); |
| } |
| |
| static int |
| pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, |
| int padding) |
| { |
| struct sshkey key; /* XXX */ |
| u_char *blob, *signature = NULL; |
| size_t blen, slen = 0; |
| int r, ret = -1; |
| struct sshbuf *msg; |
| |
| if (padding != RSA_PKCS1_PADDING) |
| return (-1); |
| key.type = KEY_RSA; |
| key.rsa = rsa; |
| if ((r = sshkey_to_blob(&key, &blob, &blen)) != 0) { |
| error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); |
| return -1; |
| } |
| if ((msg = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 || |
| (r = sshbuf_put_string(msg, blob, blen)) != 0 || |
| (r = sshbuf_put_string(msg, from, flen)) != 0 || |
| (r = sshbuf_put_u32(msg, 0)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| free(blob); |
| send_msg(msg); |
| sshbuf_reset(msg); |
| |
| if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) { |
| if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| if (slen <= (size_t)RSA_size(rsa)) { |
| memcpy(to, signature, slen); |
| ret = slen; |
| } |
| free(signature); |
| } |
| sshbuf_free(msg); |
| return (ret); |
| } |
| |
| /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ |
| static int |
| wrap_key(RSA *rsa) |
| { |
| static RSA_METHOD helper_rsa; |
| |
| memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); |
| helper_rsa.name = "ssh-pkcs11-helper"; |
| helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; |
| RSA_set_method(rsa, &helper_rsa); |
| return (0); |
| } |
| |
| static int |
| pkcs11_start_helper(void) |
| { |
| int pair[2]; |
| |
| if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { |
| error("socketpair: %s", strerror(errno)); |
| return (-1); |
| } |
| if ((pid = fork()) == -1) { |
| error("fork: %s", strerror(errno)); |
| return (-1); |
| } else if (pid == 0) { |
| if ((dup2(pair[1], STDIN_FILENO) == -1) || |
| (dup2(pair[1], STDOUT_FILENO) == -1)) { |
| fprintf(stderr, "dup2: %s\n", strerror(errno)); |
| _exit(1); |
| } |
| close(pair[0]); |
| close(pair[1]); |
| execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, |
| (char *)NULL); |
| fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, |
| strerror(errno)); |
| _exit(1); |
| } |
| close(pair[1]); |
| fd = pair[0]; |
| return (0); |
| } |
| |
| int |
| pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp) |
| { |
| struct sshkey *k; |
| int r; |
| u_char *blob; |
| size_t blen; |
| u_int nkeys, i; |
| struct sshbuf *msg; |
| |
| if (fd < 0 && pkcs11_start_helper() < 0) |
| return (-1); |
| |
| if ((msg = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 || |
| (r = sshbuf_put_cstring(msg, name)) != 0 || |
| (r = sshbuf_put_cstring(msg, pin)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| send_msg(msg); |
| sshbuf_reset(msg); |
| |
| if (recv_msg(msg) == SSH2_AGENT_IDENTITIES_ANSWER) { |
| if ((r = sshbuf_get_u32(msg, &nkeys)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| *keysp = xcalloc(nkeys, sizeof(struct sshkey *)); |
| for (i = 0; i < nkeys; i++) { |
| /* XXX clean up properly instead of fatal() */ |
| if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 || |
| (r = sshbuf_skip_string(msg)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| if ((r = sshkey_from_blob(blob, blen, &k)) != 0) |
| fatal("%s: bad key: %s", __func__, ssh_err(r)); |
| wrap_key(k->rsa); |
| (*keysp)[i] = k; |
| free(blob); |
| } |
| } else { |
| nkeys = -1; |
| } |
| sshbuf_free(msg); |
| return (nkeys); |
| } |
| |
| int |
| pkcs11_del_provider(char *name) |
| { |
| int r, ret = -1; |
| struct sshbuf *msg; |
| |
| if ((msg = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| if ((r = sshbuf_put_u8(msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY)) != 0 || |
| (r = sshbuf_put_cstring(msg, name)) != 0 || |
| (r = sshbuf_put_cstring(msg, "")) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| send_msg(msg); |
| sshbuf_reset(msg); |
| |
| if (recv_msg(msg) == SSH_AGENT_SUCCESS) |
| ret = 0; |
| sshbuf_free(msg); |
| return (ret); |
| } |
| |
| #endif /* ENABLE_PKCS11 */ |