1 /* $OpenBSD: ssh-pkcs11-client.c,v 1.2 2010/02/24 06:12:53 djm Exp $ */ 2 /* 3 * Copyright (c) 2010 Markus Friedl. All rights reserved. 4 * 5 * 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 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include "includes.h" 19 20 #ifdef ENABLE_PKCS11 21 22 #include <sys/types.h> 23 #ifdef HAVE_SYS_TIME_H 24 # include <sys/time.h> 25 #endif 26 #include <sys/socket.h> 27 28 #include <stdarg.h> 29 #include <string.h> 30 #include <unistd.h> 31 #include <errno.h> 32 33 #include "pathnames.h" 34 #include "xmalloc.h" 35 #include "buffer.h" 36 #include "log.h" 37 #include "misc.h" 38 #include "key.h" 39 #include "authfd.h" 40 #include "atomicio.h" 41 #include "ssh-pkcs11.h" 42 43 /* borrows code from sftp-server and ssh-agent */ 44 45 int fd = -1; 46 pid_t pid = -1; 47 48 static void 49 send_msg(Buffer *m) 50 { 51 u_char buf[4]; 52 int mlen = buffer_len(m); 53 54 put_u32(buf, mlen); 55 if (atomicio(vwrite, fd, buf, 4) != 4 || 56 atomicio(vwrite, fd, buffer_ptr(m), 57 buffer_len(m)) != buffer_len(m)) 58 error("write to helper failed"); 59 buffer_consume(m, mlen); 60 } 61 62 static int 63 recv_msg(Buffer *m) 64 { 65 u_int l, len; 66 u_char buf[1024]; 67 68 if ((len = atomicio(read, fd, buf, 4)) != 4) { 69 error("read from helper failed: %u", len); 70 return (0); /* XXX */ 71 } 72 len = get_u32(buf); 73 if (len > 256 * 1024) 74 fatal("response too long: %u", len); 75 /* read len bytes into m */ 76 buffer_clear(m); 77 while (len > 0) { 78 l = len; 79 if (l > sizeof(buf)) 80 l = sizeof(buf); 81 if (atomicio(read, fd, buf, l) != l) { 82 error("response from helper failed."); 83 return (0); /* XXX */ 84 } 85 buffer_append(m, buf, l); 86 len -= l; 87 } 88 return (buffer_get_char(m)); 89 } 90 91 int 92 pkcs11_init(int interactive) 93 { 94 return (0); 95 } 96 97 void 98 pkcs11_terminate(void) 99 { 100 close(fd); 101 } 102 103 static int 104 pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 105 int padding) 106 { 107 Key key; 108 u_char *blob, *signature = NULL; 109 u_int blen, slen = 0; 110 int ret = -1; 111 Buffer msg; 112 113 if (padding != RSA_PKCS1_PADDING) 114 return (-1); 115 key.type = KEY_RSA; 116 key.rsa = rsa; 117 if (key_to_blob(&key, &blob, &blen) == 0) 118 return -1; 119 buffer_init(&msg); 120 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST); 121 buffer_put_string(&msg, blob, blen); 122 buffer_put_string(&msg, from, flen); 123 buffer_put_int(&msg, 0); 124 xfree(blob); 125 send_msg(&msg); 126 127 if (recv_msg(&msg) == SSH2_AGENT_SIGN_RESPONSE) { 128 signature = buffer_get_string(&msg, &slen); 129 if (slen <= (u_int)RSA_size(rsa)) { 130 memcpy(to, signature, slen); 131 ret = slen; 132 } 133 xfree(signature); 134 } 135 return (ret); 136 } 137 138 /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ 139 static int 140 wrap_key(RSA *rsa) 141 { 142 static RSA_METHOD helper_rsa; 143 144 memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); 145 helper_rsa.name = "ssh-pkcs11-helper"; 146 helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; 147 RSA_set_method(rsa, &helper_rsa); 148 return (0); 149 } 150 151 static int 152 pkcs11_start_helper(void) 153 { 154 int pair[2]; 155 156 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 157 error("socketpair: %s", strerror(errno)); 158 return (-1); 159 } 160 if ((pid = fork()) == -1) { 161 error("fork: %s", strerror(errno)); 162 return (-1); 163 } else if (pid == 0) { 164 if ((dup2(pair[1], STDIN_FILENO) == -1) || 165 (dup2(pair[1], STDOUT_FILENO) == -1)) { 166 fprintf(stderr, "dup2: %s\n", strerror(errno)); 167 _exit(1); 168 } 169 close(pair[0]); 170 close(pair[1]); 171 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 172 (char *) 0); 173 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 174 strerror(errno)); 175 _exit(1); 176 } 177 close(pair[1]); 178 fd = pair[0]; 179 return (0); 180 } 181 182 int 183 pkcs11_add_provider(char *name, char *pin, Key ***keysp) 184 { 185 Key *k; 186 int i, nkeys; 187 u_char *blob; 188 u_int blen; 189 Buffer msg; 190 191 if (fd < 0 && pkcs11_start_helper() < 0) 192 return (-1); 193 194 buffer_init(&msg); 195 buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); 196 buffer_put_cstring(&msg, name); 197 buffer_put_cstring(&msg, pin); 198 send_msg(&msg); 199 buffer_clear(&msg); 200 201 if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 202 nkeys = buffer_get_int(&msg); 203 *keysp = xcalloc(nkeys, sizeof(Key *)); 204 for (i = 0; i < nkeys; i++) { 205 blob = buffer_get_string(&msg, &blen); 206 xfree(buffer_get_string(&msg, NULL)); 207 k = key_from_blob(blob, blen); 208 wrap_key(k->rsa); 209 (*keysp)[i] = k; 210 xfree(blob); 211 } 212 } else { 213 nkeys = -1; 214 } 215 buffer_free(&msg); 216 return (nkeys); 217 } 218 219 int 220 pkcs11_del_provider(char *name) 221 { 222 int ret = -1; 223 Buffer msg; 224 225 buffer_init(&msg); 226 buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); 227 buffer_put_cstring(&msg, name); 228 buffer_put_cstring(&msg, ""); 229 send_msg(&msg); 230 buffer_clear(&msg); 231 232 if (recv_msg(&msg) == SSH_AGENT_SUCCESS) 233 ret = 0; 234 buffer_free(&msg); 235 return (ret); 236 } 237 238 #endif /* ENABLE_PKCS11 */ 239
