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-rw-r--r--ssh-pkcs11-client.c167
1 files changed, 141 insertions, 26 deletions
diff --git a/ssh-pkcs11-client.c b/ssh-pkcs11-client.c
index d1241ce67..e7860de89 100644
--- a/ssh-pkcs11-client.c
+++ b/ssh-pkcs11-client.c
@@ -1,6 +1,7 @@
1/* $OpenBSD: ssh-pkcs11-client.c,v 1.10 2018/07/09 21:59:10 markus Exp $ */ 1/* $OpenBSD: ssh-pkcs11-client.c,v 1.15 2019/01/21 12:53:35 djm Exp $ */
2/* 2/*
3 * Copyright (c) 2010 Markus Friedl. All rights reserved. 3 * Copyright (c) 2010 Markus Friedl. All rights reserved.
4 * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
4 * 5 *
5 * Permission to use, copy, modify, and distribute this software for any 6 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above 7 * purpose with or without fee is hereby granted, provided that the above
@@ -30,6 +31,7 @@
30#include <unistd.h> 31#include <unistd.h>
31#include <errno.h> 32#include <errno.h>
32 33
34#include <openssl/ecdsa.h>
33#include <openssl/rsa.h> 35#include <openssl/rsa.h>
34 36
35#include "openbsd-compat/openssl-compat.h" 37#include "openbsd-compat/openssl-compat.h"
@@ -47,8 +49,8 @@
47 49
48/* borrows code from sftp-server and ssh-agent */ 50/* borrows code from sftp-server and ssh-agent */
49 51
50int fd = -1; 52static int fd = -1;
51pid_t pid = -1; 53static pid_t pid = -1;
52 54
53static void 55static void
54send_msg(struct sshbuf *m) 56send_msg(struct sshbuf *m)
@@ -113,22 +115,27 @@ pkcs11_terminate(void)
113} 115}
114 116
115static int 117static int
116pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 118rsa_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, int padding)
117 int padding)
118{ 119{
119 struct sshkey key; /* XXX */ 120 struct sshkey *key = NULL;
120 u_char *blob, *signature = NULL; 121 struct sshbuf *msg = NULL;
122 u_char *blob = NULL, *signature = NULL;
121 size_t blen, slen = 0; 123 size_t blen, slen = 0;
122 int r, ret = -1; 124 int r, ret = -1;
123 struct sshbuf *msg;
124 125
125 if (padding != RSA_PKCS1_PADDING) 126 if (padding != RSA_PKCS1_PADDING)
126 return (-1); 127 goto fail;
127 key.type = KEY_RSA; 128 key = sshkey_new(KEY_UNSPEC);
128 key.rsa = rsa; 129 if (key == NULL) {
129 if ((r = sshkey_to_blob(&key, &blob, &blen)) != 0) { 130 error("%s: sshkey_new failed", __func__);
131 goto fail;
132 }
133 key->type = KEY_RSA;
134 RSA_up_ref(rsa);
135 key->rsa = rsa;
136 if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
130 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 137 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
131 return -1; 138 goto fail;
132 } 139 }
133 if ((msg = sshbuf_new()) == NULL) 140 if ((msg = sshbuf_new()) == NULL)
134 fatal("%s: sshbuf_new failed", __func__); 141 fatal("%s: sshbuf_new failed", __func__);
@@ -137,7 +144,6 @@ pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
137 (r = sshbuf_put_string(msg, from, flen)) != 0 || 144 (r = sshbuf_put_string(msg, from, flen)) != 0 ||
138 (r = sshbuf_put_u32(msg, 0)) != 0) 145 (r = sshbuf_put_u32(msg, 0)) != 0)
139 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 146 fatal("%s: buffer error: %s", __func__, ssh_err(r));
140 free(blob);
141 send_msg(msg); 147 send_msg(msg);
142 sshbuf_reset(msg); 148 sshbuf_reset(msg);
143 149
@@ -150,22 +156,115 @@ pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa,
150 } 156 }
151 free(signature); 157 free(signature);
152 } 158 }
159 fail:
160 free(blob);
161 sshkey_free(key);
162 sshbuf_free(msg);
163 return (ret);
164}
165
166#ifdef HAVE_EC_KEY_METHOD_NEW
167static ECDSA_SIG *
168ecdsa_do_sign(const unsigned char *dgst, int dgst_len, const BIGNUM *inv,
169 const BIGNUM *rp, EC_KEY *ec)
170{
171 struct sshkey *key = NULL;
172 struct sshbuf *msg = NULL;
173 ECDSA_SIG *ret = NULL;
174 const u_char *cp;
175 u_char *blob = NULL, *signature = NULL;
176 size_t blen, slen = 0;
177 int r, nid;
178
179 nid = sshkey_ecdsa_key_to_nid(ec);
180 if (nid < 0) {
181 error("%s: couldn't get curve nid", __func__);
182 goto fail;
183 }
184
185 key = sshkey_new(KEY_UNSPEC);
186 if (key == NULL) {
187 error("%s: sshkey_new failed", __func__);
188 goto fail;
189 }
190 key->ecdsa = ec;
191 key->ecdsa_nid = nid;
192 key->type = KEY_ECDSA;
193 EC_KEY_up_ref(ec);
194
195 if ((r = sshkey_to_blob(key, &blob, &blen)) != 0) {
196 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
197 goto fail;
198 }
199 if ((msg = sshbuf_new()) == NULL)
200 fatal("%s: sshbuf_new failed", __func__);
201 if ((r = sshbuf_put_u8(msg, SSH2_AGENTC_SIGN_REQUEST)) != 0 ||
202 (r = sshbuf_put_string(msg, blob, blen)) != 0 ||
203 (r = sshbuf_put_string(msg, dgst, dgst_len)) != 0 ||
204 (r = sshbuf_put_u32(msg, 0)) != 0)
205 fatal("%s: buffer error: %s", __func__, ssh_err(r));
206 send_msg(msg);
207 sshbuf_reset(msg);
208
209 if (recv_msg(msg) == SSH2_AGENT_SIGN_RESPONSE) {
210 if ((r = sshbuf_get_string(msg, &signature, &slen)) != 0)
211 fatal("%s: buffer error: %s", __func__, ssh_err(r));
212 cp = signature;
213 ret = d2i_ECDSA_SIG(NULL, &cp, slen);
214 free(signature);
215 }
216
217 fail:
218 free(blob);
219 sshkey_free(key);
153 sshbuf_free(msg); 220 sshbuf_free(msg);
154 return (ret); 221 return (ret);
155} 222}
223#endif /* HAVE_EC_KEY_METHOD_NEW */
224
225static RSA_METHOD *helper_rsa;
226#ifdef HAVE_EC_KEY_METHOD_NEW
227static EC_KEY_METHOD *helper_ecdsa;
228#endif /* HAVE_EC_KEY_METHOD_NEW */
229
230/* redirect private key crypto operations to the ssh-pkcs11-helper */
231static void
232wrap_key(struct sshkey *k)
233{
234 if (k->type == KEY_RSA)
235 RSA_set_method(k->rsa, helper_rsa);
236#ifdef HAVE_EC_KEY_METHOD_NEW
237 else if (k->type == KEY_ECDSA)
238 EC_KEY_set_method(k->ecdsa, helper_ecdsa);
239#endif /* HAVE_EC_KEY_METHOD_NEW */
240 else
241 fatal("%s: unknown key type", __func__);
242}
156 243
157/* redirect the private key encrypt operation to the ssh-pkcs11-helper */
158static int 244static int
159wrap_key(RSA *rsa) 245pkcs11_start_helper_methods(void)
160{ 246{
161 static RSA_METHOD *helper_rsa; 247 if (helper_rsa != NULL)
248 return (0);
249
250#ifdef HAVE_EC_KEY_METHOD_NEW
251 int (*orig_sign)(int, const unsigned char *, int, unsigned char *,
252 unsigned int *, const BIGNUM *, const BIGNUM *, EC_KEY *) = NULL;
253 if (helper_ecdsa != NULL)
254 return (0);
255 helper_ecdsa = EC_KEY_METHOD_new(EC_KEY_OpenSSL());
256 if (helper_ecdsa == NULL)
257 return (-1);
258 EC_KEY_METHOD_get_sign(helper_ecdsa, &orig_sign, NULL, NULL);
259 EC_KEY_METHOD_set_sign(helper_ecdsa, orig_sign, NULL, ecdsa_do_sign);
260#endif /* HAVE_EC_KEY_METHOD_NEW */
162 261
163 if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL) 262 if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL)
164 fatal("%s: RSA_meth_dup failed", __func__); 263 fatal("%s: RSA_meth_dup failed", __func__);
165 if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") || 264 if (!RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper") ||
166 !RSA_meth_set_priv_enc(helper_rsa, pkcs11_rsa_private_encrypt)) 265 !RSA_meth_set_priv_enc(helper_rsa, rsa_encrypt))
167 fatal("%s: failed to prepare method", __func__); 266 fatal("%s: failed to prepare method", __func__);
168 RSA_set_method(rsa, helper_rsa); 267
169 return (0); 268 return (0);
170} 269}
171 270
@@ -173,6 +272,15 @@ static int
173pkcs11_start_helper(void) 272pkcs11_start_helper(void)
174{ 273{
175 int pair[2]; 274 int pair[2];
275 char *helper, *verbosity = NULL;
276
277 if (log_level_get() >= SYSLOG_LEVEL_DEBUG1)
278 verbosity = "-vvv";
279
280 if (pkcs11_start_helper_methods() == -1) {
281 error("pkcs11_start_helper_methods failed");
282 return (-1);
283 }
176 284
177 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 285 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) {
178 error("socketpair: %s", strerror(errno)); 286 error("socketpair: %s", strerror(errno));
@@ -189,10 +297,13 @@ pkcs11_start_helper(void)
189 } 297 }
190 close(pair[0]); 298 close(pair[0]);
191 close(pair[1]); 299 close(pair[1]);
192 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 300 helper = getenv("SSH_PKCS11_HELPER");
193 (char *)NULL); 301 if (helper == NULL || strlen(helper) == 0)
194 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 302 helper = _PATH_SSH_PKCS11_HELPER;
195 strerror(errno)); 303 debug("%s: starting %s %s", __func__, helper,
304 verbosity == NULL ? "" : verbosity);
305 execlp(helper, helper, verbosity, (char *)NULL);
306 fprintf(stderr, "exec: %s: %s\n", helper, strerror(errno));
196 _exit(1); 307 _exit(1);
197 } 308 }
198 close(pair[1]); 309 close(pair[1]);
@@ -204,7 +315,7 @@ int
204pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp) 315pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp)
205{ 316{
206 struct sshkey *k; 317 struct sshkey *k;
207 int r; 318 int r, type;
208 u_char *blob; 319 u_char *blob;
209 size_t blen; 320 size_t blen;
210 u_int nkeys, i; 321 u_int nkeys, i;
@@ -222,7 +333,8 @@ pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp)
222 send_msg(msg); 333 send_msg(msg);
223 sshbuf_reset(msg); 334 sshbuf_reset(msg);
224 335
225 if (recv_msg(msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 336 type = recv_msg(msg);
337 if (type == SSH2_AGENT_IDENTITIES_ANSWER) {
226 if ((r = sshbuf_get_u32(msg, &nkeys)) != 0) 338 if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
227 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 339 fatal("%s: buffer error: %s", __func__, ssh_err(r));
228 *keysp = xcalloc(nkeys, sizeof(struct sshkey *)); 340 *keysp = xcalloc(nkeys, sizeof(struct sshkey *));
@@ -234,10 +346,13 @@ pkcs11_add_provider(char *name, char *pin, struct sshkey ***keysp)
234 __func__, ssh_err(r)); 346 __func__, ssh_err(r));
235 if ((r = sshkey_from_blob(blob, blen, &k)) != 0) 347 if ((r = sshkey_from_blob(blob, blen, &k)) != 0)
236 fatal("%s: bad key: %s", __func__, ssh_err(r)); 348 fatal("%s: bad key: %s", __func__, ssh_err(r));
237 wrap_key(k->rsa); 349 wrap_key(k);
238 (*keysp)[i] = k; 350 (*keysp)[i] = k;
239 free(blob); 351 free(blob);
240 } 352 }
353 } else if (type == SSH2_AGENT_FAILURE) {
354 if ((r = sshbuf_get_u32(msg, &nkeys)) != 0)
355 nkeys = -1;
241 } else { 356 } else {
242 nkeys = -1; 357 nkeys = -1;
243 } 358 }