Annotation of src/usr.bin/ssh/ssh-pkcs11-client.c, Revision 1.14
1.14 ! djm 1: /* $OpenBSD: ssh-pkcs11-client.c,v 1.13 2019/01/20 22:54:30 djm Exp $ */
1.1 markus 2: /*
3: * Copyright (c) 2010 Markus Friedl. All rights reserved.
1.12 djm 4: * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
1.1 markus 5: *
6: * Permission to use, copy, modify, and distribute this software for any
7: * purpose with or without fee is hereby granted, provided that the above
8: * copyright notice and this permission notice appear in all copies.
9: *
10: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17: */
18:
19: #include <sys/types.h>
20: #include <sys/time.h>
21: #include <sys/socket.h>
22:
23: #include <stdarg.h>
24: #include <string.h>
25: #include <unistd.h>
26: #include <errno.h>
1.5 djm 27:
1.12 djm 28: #include <openssl/ecdsa.h>
1.5 djm 29: #include <openssl/rsa.h>
1.1 markus 30:
31: #include "pathnames.h"
32: #include "xmalloc.h"
1.9 markus 33: #include "sshbuf.h"
1.1 markus 34: #include "log.h"
35: #include "misc.h"
1.9 markus 36: #include "sshkey.h"
1.1 markus 37: #include "authfd.h"
38: #include "atomicio.h"
39: #include "ssh-pkcs11.h"
1.9 markus 40: #include "ssherr.h"
1.1 markus 41:
42: /* borrows code from sftp-server and ssh-agent */
43:
44: int fd = -1;
45: pid_t pid = -1;
46:
47: static void
1.9 markus 48: send_msg(struct sshbuf *m)
1.1 markus 49: {
50: u_char buf[4];
1.9 markus 51: size_t mlen = sshbuf_len(m);
52: int r;
1.1 markus 53:
1.9 markus 54: POKE_U32(buf, mlen);
1.1 markus 55: if (atomicio(vwrite, fd, buf, 4) != 4 ||
1.10 markus 56: atomicio(vwrite, fd, sshbuf_mutable_ptr(m),
1.9 markus 57: sshbuf_len(m)) != sshbuf_len(m))
1.1 markus 58: error("write to helper failed");
1.9 markus 59: if ((r = sshbuf_consume(m, mlen)) != 0)
60: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 61: }
62:
63: static int
1.9 markus 64: recv_msg(struct sshbuf *m)
1.1 markus 65: {
66: u_int l, len;
1.9 markus 67: u_char c, buf[1024];
68: int r;
1.1 markus 69:
70: if ((len = atomicio(read, fd, buf, 4)) != 4) {
71: error("read from helper failed: %u", len);
72: return (0); /* XXX */
73: }
1.9 markus 74: len = PEEK_U32(buf);
1.1 markus 75: if (len > 256 * 1024)
76: fatal("response too long: %u", len);
77: /* read len bytes into m */
1.9 markus 78: sshbuf_reset(m);
1.1 markus 79: while (len > 0) {
80: l = len;
81: if (l > sizeof(buf))
82: l = sizeof(buf);
83: if (atomicio(read, fd, buf, l) != l) {
84: error("response from helper failed.");
85: return (0); /* XXX */
86: }
1.9 markus 87: if ((r = sshbuf_put(m, buf, l)) != 0)
88: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.1 markus 89: len -= l;
90: }
1.9 markus 91: if ((r = sshbuf_get_u8(m, &c)) != 0)
92: fatal("%s: buffer error: %s", __func__, ssh_err(r));
93: return c;
1.1 markus 94: }
95:
96: int
97: pkcs11_init(int interactive)
98: {
99: return (0);
100: }
101:
102: void
103: pkcs11_terminate(void)
104: {
1.8 tb 105: if (fd >= 0)
106: close(fd);
1.1 markus 107: }
108:
109: static int
1.12 djm 110: rsa_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, int padding)
1.1 markus 111: {
1.14 ! djm 112: struct sshkey *key = NULL;
! 113: struct sshbuf *msg = NULL;
! 114: u_char *blob = NULL, *signature = NULL;
1.9 markus 115: size_t blen, slen = 0;
116: int r, ret = -1;
1.1 markus 117:
118: if (padding != RSA_PKCS1_PADDING)
1.14 ! djm 119: goto fail;
! 120: key = sshkey_new(KEY_UNSPEC);
! 121: if (key == NULL) {
! 122: error("%s: sshkey_new failed", __func__);
! 123: goto fail;
! 124: }
! 125: key->type = KEY_RSA;
! 126: RSA_up_ref(rsa);
! 127: key->rsa = rsa;
! 128: if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
1.9 markus 129: error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
1.14 ! djm 130: goto fail;
1.9 markus 131: }
132: if ((msg = sshbuf_new()) == NULL)
133: fatal("%s: sshbuf_new failed", __func__);
134: if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
135: (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
136: (r = sshbuf_put_string(msg, from, flen)) != 0 ||
137: (r = sshbuf_put_u32(msg, 0)) != 0)
138: fatal("%s: buffer error: %s", __func__, ssh_err(r));
139: send_msg(msg);
140: sshbuf_reset(msg);
1.1 markus 141:
1.9 markus 142: if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
143: if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
144: fatal("%s: buffer error: %s", __func__, ssh_err(r));
145: if (slen <= (size_t)RSA_size(rsa)) {
1.1 markus 146: memcpy(to, signature, slen);
147: ret = slen;
148: }
1.4 djm 149: free(signature);
1.1 markus 150: }
1.14 ! djm 151: fail:
! 152: free(blob);
! 153: sshkey_free(key);
1.9 markus 154: sshbuf_free(msg);
1.1 markus 155: return (ret);
156: }
157:
1.12 djm 158: static ECDSA_SIG *
159: ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
160: const BIGNUM *rp, EC_KEY *ec)
161: {
1.14 ! djm 162: struct sshkey *key = NULL;
! 163: struct sshbuf *msg = NULL;
! 164: ECDSA_SIG *ret = NULL;
1.12 djm 165: const u_char *cp;
1.14 ! djm 166: u_char *blob = NULL, *signature = NULL;
1.12 djm 167: size_t blen, slen = 0;
1.14 ! djm 168: int r, nid;
1.12 djm 169:
1.14 ! djm 170: nid = sshkey_ecdsa_key_to_nid(ec);
! 171: if (nid < 0) {
1.12 djm 172: error("%s: couldn't get curve nid", __func__);
1.14 ! djm 173: goto fail;
1.12 djm 174: }
1.14 ! djm 175:
! 176: key = sshkey_new(KEY_UNSPEC);
! 177: if (key == NULL) {
! 178: error("%s: sshkey_new failed", __func__);
! 179: goto fail;
! 180: }
! 181: key->ecdsa = ec;
! 182: key->ecdsa_nid = nid;
! 183: key->type = KEY_ECDSA;
! 184: EC_KEY_up_ref(ec);
! 185:
! 186: if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
1.12 djm 187: error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
1.14 ! djm 188: goto fail;
1.12 djm 189: }
190: if ((msg = sshbuf_new()) == NULL)
191: fatal("%s: sshbuf_new failed", __func__);
192: if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
193: (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
194: (r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
195: (r = sshbuf_put_u32(msg, 0)) != 0)
196: fatal("%s: buffer error: %s", __func__, ssh_err(r));
197: send_msg(msg);
198: sshbuf_reset(msg);
199:
200: if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
201: if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
202: fatal("%s: buffer error: %s", __func__, ssh_err(r));
203: cp = signature;
204: ret = d2i_ECDSA_SIG(NULL, &cp, slen);
205: free(signature);
206: }
207:
1.14 ! djm 208: fail:
! 209: free(blob);
! 210: sshkey_free(key);
1.12 djm 211: sshbuf_free(msg);
212: return (ret);
213: }
214:
215: static RSA_METHOD *helper_rsa;
216: static EC_KEY_METHOD *helper_ecdsa;
217:
218: /* redirect private key crypto operations to the ssh-pkcs11-helper */
219: static void
220: wrap_key(struct sshkey *k)
221: {
222: if (k->type == KEY_RSA)
223: RSA_set_method(k->rsa, helper_rsa);
224: else if (k->type == KEY_ECDSA)
225: EC_KEY_set_method(k->ecdsa, helper_ecdsa);
226: else
227: fatal("%s: unknown key type", __func__);
228: }
229:
1.1 markus 230: static int
1.12 djm 231: pkcs11_start_helper_methods(void)
1.1 markus 232: {
1.12 djm 233: if (helper_ecdsa != NULL)
234: return (0);
235:
236: int (*orig_sign)(int, const unsigned char *, int, unsigned char *,
237: unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
238: if (helper_ecdsa != NULL)
239: return (0);
240: helper_ecdsa = EC_KEY_METHOD_new(EC_KEY_OpenSSL());
241: if (helper_ecdsa == NULL)
242: return (-1);
243: EC_KEY_METHOD_get_sign(helper_ecdsa, &orig_sign, NULL, NULL);
244: EC_KEY_METHOD_set_sign(helper_ecdsa, orig_sign, NULL, ecdsa_do_sign);
1.1 markus 245:
1.11 djm 246: if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL)
247: fatal("%s: RSA_meth_dup failed", __func__);
248: if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") ||
1.12 djm 249: !RSA_meth_set_priv_enc(helper_rsa, rsa_encrypt))
1.11 djm 250: fatal("%s: failed to prepare method", __func__);
1.12 djm 251:
1.1 markus 252: return (0);
253: }
254:
255: static int
256: pkcs11_start_helper(void)
257: {
258: int pair[2];
1.13 djm 259: char *helper;
1.1 markus 260:
1.12 djm 261: if (pkcs11_start_helper_methods() == -1) {
262: error("pkcs11_start_helper_methods failed");
263: return (-1);
264: }
265:
1.1 markus 266: if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
267: error("socketpair: %s", strerror(errno));
268: return (-1);
269: }
270: if ((pid = fork()) == -1) {
271: error("fork: %s", strerror(errno));
272: return (-1);
273: } else if (pid == 0) {
274: if ((dup2(pair[1], STDIN_FILENO) == -1) ||
275: (dup2(pair[1], STDOUT_FILENO) == -1)) {
276: fprintf(stderr, "dup2: %s\n", strerror(errno));
277: _exit(1);
278: }
279: close(pair[0]);
280: close(pair[1]);
1.13 djm 281: helper = getenv("SSH_PKCS11_HELPER");
282: if (helper == NULL || strlen(helper) == 0)
283: helper = _PATH_SSH_PKCS11_HELPER;
284: execlp(helper, helper, (char *)NULL);
285: fprintf(stderr, "exec: %s: %s\n", helper, strerror(errno));
1.1 markus 286: _exit(1);
287: }
288: close(pair[1]);
289: fd = pair[0];
290: return (0);
291: }
292:
293: int
1.9 markus 294: pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp)
1.1 markus 295: {
1.7 markus 296: struct sshkey *k;
1.12 djm 297: int r, type;
1.1 markus 298: u_char *blob;
1.9 markus 299: size_t blen;
300: u_int nkeys, i;
301: struct sshbuf *msg;
1.1 markus 302:
303: if (fd < 0 && pkcs11_start_helper() < 0)
304: return (-1);
305:
1.9 markus 306: if ((msg = sshbuf_new()) == NULL)
307: fatal("%s: sshbuf_new failed", __func__);
308: if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 ||
309: (r = sshbuf_put_cstring(msg, name)) != 0 ||
310: (r = sshbuf_put_cstring(msg, pin)) != 0)
311: fatal("%s: buffer error: %s", __func__, ssh_err(r));
312: send_msg(msg);
313: sshbuf_reset(msg);
314:
1.12 djm 315: type = recv_msg(msg);
316: if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
1.9 markus 317: if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
318: fatal("%s: buffer error: %s", __func__, ssh_err(r));
319: *keysp = xcalloc(nkeys, sizeof(struct sshkey *));
1.1 markus 320: for (i = 0; i < nkeys; i++) {
1.9 markus 321: /* XXX clean up properly instead of fatal() */
322: if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 ||
323: (r = sshbuf_skip_string(msg)) != 0)
324: fatal("%s: buffer error: %s",
325: __func__, ssh_err(r));
326: if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
327: fatal("%s: bad key: %s", __func__, ssh_err(r));
1.12 djm 328: wrap_key(k);
1.1 markus 329: (*keysp)[i] = k;
1.4 djm 330: free(blob);
1.1 markus 331: }
1.12 djm 332: } else if (type == SSH2_AGENT_FAILURE) {
333: if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
334: nkeys = -1;
1.1 markus 335: } else {
336: nkeys = -1;
337: }
1.9 markus 338: sshbuf_free(msg);
1.1 markus 339: return (nkeys);
340: }
341:
342: int
343: pkcs11_del_provider(char *name)
344: {
1.9 markus 345: int r, ret = -1;
346: struct sshbuf *msg;
1.1 markus 347:
1.9 markus 348: if ((msg = sshbuf_new()) == NULL)
349: fatal("%s: sshbuf_new failed", __func__);
350: if ((r = sshbuf_put_u8(msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY)) != 0 ||
351: (r = sshbuf_put_cstring(msg, name)) != 0 ||
352: (r = sshbuf_put_cstring(msg, "")) != 0)
353: fatal("%s: buffer error: %s", __func__, ssh_err(r));
354: send_msg(msg);
355: sshbuf_reset(msg);
1.1 markus 356:
1.9 markus 357: if (recv_msg(msg) == SSH_AGENT_SUCCESS)
1.1 markus 358: ret = 0;
1.9 markus 359: sshbuf_free(msg);
1.1 markus 360: return (ret);
361: }
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