Annotation of src/usr.bin/ssh/ssh-pkcs11-client.c, Revision 1.13
1.13 ! djm 1: /* $OpenBSD: ssh-pkcs11-client.c,v 1.12 2019/01/20 22:51:37 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: {
1.7 markus 112: struct sshkey key; /* XXX */
1.1 markus 113: u_char *blob, *signature = NULL;
1.9 markus 114: size_t blen, slen = 0;
115: int r, ret = -1;
116: struct sshbuf *msg;
1.1 markus 117:
118: if (padding != RSA_PKCS1_PADDING)
119: return (-1);
120: key.type = KEY_RSA;
121: key.rsa = rsa;
1.9 markus 122: if ((r = sshkey_to_blob(&key, &blob, &blen)) != 0) {
123: error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
1.1 markus 124: return -1;
1.9 markus 125: }
126: if ((msg = sshbuf_new()) == NULL)
127: fatal("%s: sshbuf_new failed", __func__);
128: if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
129: (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
130: (r = sshbuf_put_string(msg, from, flen)) != 0 ||
131: (r = sshbuf_put_u32(msg, 0)) != 0)
132: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.4 djm 133: free(blob);
1.9 markus 134: send_msg(msg);
135: sshbuf_reset(msg);
1.1 markus 136:
1.9 markus 137: if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
138: if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
139: fatal("%s: buffer error: %s", __func__, ssh_err(r));
140: if (slen <= (size_t)RSA_size(rsa)) {
1.1 markus 141: memcpy(to, signature, slen);
142: ret = slen;
143: }
1.4 djm 144: free(signature);
1.1 markus 145: }
1.9 markus 146: sshbuf_free(msg);
1.1 markus 147: return (ret);
148: }
149:
1.12 djm 150: static ECDSA_SIG *
151: ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
152: const BIGNUM *rp, EC_KEY *ec)
153: {
154: struct sshkey key; /* XXX */
155: u_char *blob, *signature = NULL;
156: const u_char *cp;
157: size_t blen, slen = 0;
158: ECDSA_SIG *ret = NULL;
159: struct sshbuf *msg;
160: int r;
161:
162: key.type = KEY_ECDSA;
163: key.ecdsa = ec;
164: key.ecdsa_nid = sshkey_ecdsa_key_to_nid(ec);
165: if (key.ecdsa_nid < 0) {
166: error("%s: couldn't get curve nid", __func__);
167: return (NULL);
168: }
169: if ((r = sshkey_to_blob(&key, &blob, &blen)) != 0) {
170: error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
171: return (NULL);
172: }
173: if ((msg = sshbuf_new()) == NULL)
174: fatal("%s: sshbuf_new failed", __func__);
175: if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
176: (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
177: (r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
178: (r = sshbuf_put_u32(msg, 0)) != 0)
179: fatal("%s: buffer error: %s", __func__, ssh_err(r));
180: free(blob);
181: send_msg(msg);
182: sshbuf_reset(msg);
183:
184: if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
185: if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
186: fatal("%s: buffer error: %s", __func__, ssh_err(r));
187: cp = signature;
188: ret = d2i_ECDSA_SIG(NULL, &cp, slen);
189: free(signature);
190: }
191:
192: sshbuf_free(msg);
193: return (ret);
194: }
195:
196: static RSA_METHOD *helper_rsa;
197: static EC_KEY_METHOD *helper_ecdsa;
198:
199: /* redirect private key crypto operations to the ssh-pkcs11-helper */
200: static void
201: wrap_key(struct sshkey *k)
202: {
203: if (k->type == KEY_RSA)
204: RSA_set_method(k->rsa, helper_rsa);
205: else if (k->type == KEY_ECDSA)
206: EC_KEY_set_method(k->ecdsa, helper_ecdsa);
207: else
208: fatal("%s: unknown key type", __func__);
209: }
210:
1.1 markus 211: static int
1.12 djm 212: pkcs11_start_helper_methods(void)
1.1 markus 213: {
1.12 djm 214: if (helper_ecdsa != NULL)
215: return (0);
216:
217: int (*orig_sign)(int, const unsigned char *, int, unsigned char *,
218: unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
219: if (helper_ecdsa != NULL)
220: return (0);
221: helper_ecdsa = EC_KEY_METHOD_new(EC_KEY_OpenSSL());
222: if (helper_ecdsa == NULL)
223: return (-1);
224: EC_KEY_METHOD_get_sign(helper_ecdsa, &orig_sign, NULL, NULL);
225: EC_KEY_METHOD_set_sign(helper_ecdsa, orig_sign, NULL, ecdsa_do_sign);
1.1 markus 226:
1.11 djm 227: if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL)
228: fatal("%s: RSA_meth_dup failed", __func__);
229: if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") ||
1.12 djm 230: !RSA_meth_set_priv_enc(helper_rsa, rsa_encrypt))
1.11 djm 231: fatal("%s: failed to prepare method", __func__);
1.12 djm 232:
1.1 markus 233: return (0);
234: }
235:
236: static int
237: pkcs11_start_helper(void)
238: {
239: int pair[2];
1.13 ! djm 240: char *helper;
1.1 markus 241:
1.12 djm 242: if (pkcs11_start_helper_methods() == -1) {
243: error("pkcs11_start_helper_methods failed");
244: return (-1);
245: }
246:
1.1 markus 247: if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
248: error("socketpair: %s", strerror(errno));
249: return (-1);
250: }
251: if ((pid = fork()) == -1) {
252: error("fork: %s", strerror(errno));
253: return (-1);
254: } else if (pid == 0) {
255: if ((dup2(pair[1], STDIN_FILENO) == -1) ||
256: (dup2(pair[1], STDOUT_FILENO) == -1)) {
257: fprintf(stderr, "dup2: %s\n", strerror(errno));
258: _exit(1);
259: }
260: close(pair[0]);
261: close(pair[1]);
1.13 ! djm 262: helper = getenv("SSH_PKCS11_HELPER");
! 263: if (helper == NULL || strlen(helper) == 0)
! 264: helper = _PATH_SSH_PKCS11_HELPER;
! 265: execlp(helper, helper, (char *)NULL);
! 266: fprintf(stderr, "exec: %s: %s\n", helper, strerror(errno));
1.1 markus 267: _exit(1);
268: }
269: close(pair[1]);
270: fd = pair[0];
271: return (0);
272: }
273:
274: int
1.9 markus 275: pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp)
1.1 markus 276: {
1.7 markus 277: struct sshkey *k;
1.12 djm 278: int r, type;
1.1 markus 279: u_char *blob;
1.9 markus 280: size_t blen;
281: u_int nkeys, i;
282: struct sshbuf *msg;
1.1 markus 283:
284: if (fd < 0 && pkcs11_start_helper() < 0)
285: return (-1);
286:
1.9 markus 287: if ((msg = sshbuf_new()) == NULL)
288: fatal("%s: sshbuf_new failed", __func__);
289: if ((r = sshbuf_put_u8(msg, SSH_AGENTC_ADD_SMARTCARD_KEY)) != 0 ||
290: (r = sshbuf_put_cstring(msg, name)) != 0 ||
291: (r = sshbuf_put_cstring(msg, pin)) != 0)
292: fatal("%s: buffer error: %s", __func__, ssh_err(r));
293: send_msg(msg);
294: sshbuf_reset(msg);
295:
1.12 djm 296: type = recv_msg(msg);
297: if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
1.9 markus 298: if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
299: fatal("%s: buffer error: %s", __func__, ssh_err(r));
300: *keysp = xcalloc(nkeys, sizeof(struct sshkey *));
1.1 markus 301: for (i = 0; i < nkeys; i++) {
1.9 markus 302: /* XXX clean up properly instead of fatal() */
303: if ((r = sshbuf_get_string(msg, &blob, &blen)) != 0 ||
304: (r = sshbuf_skip_string(msg)) != 0)
305: fatal("%s: buffer error: %s",
306: __func__, ssh_err(r));
307: if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
308: fatal("%s: bad key: %s", __func__, ssh_err(r));
1.12 djm 309: wrap_key(k);
1.1 markus 310: (*keysp)[i] = k;
1.4 djm 311: free(blob);
1.1 markus 312: }
1.12 djm 313: } else if (type == SSH2_AGENT_FAILURE) {
314: if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
315: nkeys = -1;
1.1 markus 316: } else {
317: nkeys = -1;
318: }
1.9 markus 319: sshbuf_free(msg);
1.1 markus 320: return (nkeys);
321: }
322:
323: int
324: pkcs11_del_provider(char *name)
325: {
1.9 markus 326: int r, ret = -1;
327: struct sshbuf *msg;
1.1 markus 328:
1.9 markus 329: if ((msg = sshbuf_new()) == NULL)
330: fatal("%s: sshbuf_new failed", __func__);
331: if ((r = sshbuf_put_u8(msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY)) != 0 ||
332: (r = sshbuf_put_cstring(msg, name)) != 0 ||
333: (r = sshbuf_put_cstring(msg, "")) != 0)
334: fatal("%s: buffer error: %s", __func__, ssh_err(r));
335: send_msg(msg);
336: sshbuf_reset(msg);
1.1 markus 337:
1.9 markus 338: if (recv_msg(msg) == SSH_AGENT_SUCCESS)
1.1 markus 339: ret = 0;
1.9 markus 340: sshbuf_free(msg);
1.1 markus 341: return (ret);
342: }