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Diffstat (limited to '')
| -rw-r--r-- | ssh-pkcs11-client.c | 269 |
1 files changed, 269 insertions, 0 deletions
diff --git a/ssh-pkcs11-client.c b/ssh-pkcs11-client.c new file mode 100644 index 0000000..d1241ce --- /dev/null +++ b/ssh-pkcs11-client.c @@ -0,0 +1,269 @@ +/* $OpenBSD: ssh-pkcs11-client.c,v 1.10 2018/07/09 21:59:10 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 "openbsd-compat/openssl-compat.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, sshbuf_mutable_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; + + if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL) + fatal("%s: RSA_meth_dup failed", __func__); + if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") || + !RSA_meth_set_priv_enc(helper_rsa, pkcs11_rsa_private_encrypt)) + fatal("%s: failed to prepare method", __func__); + 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 */ |