1 /* $OpenBSD: ssh-pkcs11-client.c,v 1.5 2014/06/24 01:13:21 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 <openssl/rsa.h> 34 35 #include "pathnames.h" 36 #include "xmalloc.h" 37 #include "buffer.h" 38 #include "log.h" 39 #include "misc.h" 40 #include "key.h" 41 #include "authfd.h" 42 #include "atomicio.h" 43 #include "ssh-pkcs11.h" 44 45 /* borrows code from sftp-server and ssh-agent */ 46 47 int fd = -1; 48 pid_t pid = -1; 49 50 static void 51 send_msg(Buffer *m) 52 { 53 u_char buf[4]; 54 int mlen = buffer_len(m); 55 56 put_u32(buf, mlen); 57 if (atomicio(vwrite, fd, buf, 4) != 4 || 58 atomicio(vwrite, fd, buffer_ptr(m), 59 buffer_len(m)) != buffer_len(m)) 60 error("write to helper failed"); 61 buffer_consume(m, mlen); 62 } 63 64 static int 65 recv_msg(Buffer *m) 66 { 67 u_int l, len; 68 u_char buf[1024]; 69 70 if ((len = atomicio(read, fd, buf, 4)) != 4) { 71 error("read from helper failed: %u", len); 72 return (0); /* XXX */ 73 } 74 len = get_u32(buf); 75 if (len > 256 * 1024) 76 fatal("response too long: %u", len); 77 /* read len bytes into m */ 78 buffer_clear(m); 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 } 87 buffer_append(m, buf, l); 88 len -= l; 89 } 90 return (buffer_get_char(m)); 91 } 92 93 int 94 pkcs11_init(int interactive) 95 { 96 return (0); 97 } 98 99 void 100 pkcs11_terminate(void) 101 { 102 close(fd); 103 } 104 105 static int 106 pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 107 int padding) 108 { 109 Key key; 110 u_char *blob, *signature = NULL; 111 u_int blen, slen = 0; 112 int ret = -1; 113 Buffer msg; 114 115 if (padding != RSA_PKCS1_PADDING) 116 return (-1); 117 key.type = KEY_RSA; 118 key.rsa = rsa; 119 if (key_to_blob(&key, &blob, &blen) == 0) 120 return -1; 121 buffer_init(&msg); 122 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST); 123 buffer_put_string(&msg, blob, blen); 124 buffer_put_string(&msg, from, flen); 125 buffer_put_int(&msg, 0); 126 free(blob); 127 send_msg(&msg); 128 buffer_clear(&msg); 129 130 if (recv_msg(&msg) == SSH2_AGENT_SIGN_RESPONSE) { 131 signature = buffer_get_string(&msg, &slen); 132 if (slen <= (u_int)RSA_size(rsa)) { 133 memcpy(to, signature, slen); 134 ret = slen; 135 } 136 free(signature); 137 } 138 buffer_free(&msg); 139 return (ret); 140 } 141 142 /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ 143 static int 144 wrap_key(RSA *rsa) 145 { 146 static RSA_METHOD helper_rsa; 147 148 memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); 149 helper_rsa.name = "ssh-pkcs11-helper"; 150 helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; 151 RSA_set_method(rsa, &helper_rsa); 152 return (0); 153 } 154 155 static int 156 pkcs11_start_helper(void) 157 { 158 int pair[2]; 159 160 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 161 error("socketpair: %s", strerror(errno)); 162 return (-1); 163 } 164 if ((pid = fork()) == -1) { 165 error("fork: %s", strerror(errno)); 166 return (-1); 167 } else if (pid == 0) { 168 if ((dup2(pair[1], STDIN_FILENO) == -1) || 169 (dup2(pair[1], STDOUT_FILENO) == -1)) { 170 fprintf(stderr, "dup2: %s\n", strerror(errno)); 171 _exit(1); 172 } 173 close(pair[0]); 174 close(pair[1]); 175 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 176 (char *) 0); 177 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 178 strerror(errno)); 179 _exit(1); 180 } 181 close(pair[1]); 182 fd = pair[0]; 183 return (0); 184 } 185 186 int 187 pkcs11_add_provider(char *name, char *pin, Key ***keysp) 188 { 189 Key *k; 190 int i, nkeys; 191 u_char *blob; 192 u_int blen; 193 Buffer msg; 194 195 if (fd < 0 && pkcs11_start_helper() < 0) 196 return (-1); 197 198 buffer_init(&msg); 199 buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); 200 buffer_put_cstring(&msg, name); 201 buffer_put_cstring(&msg, pin); 202 send_msg(&msg); 203 buffer_clear(&msg); 204 205 if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 206 nkeys = buffer_get_int(&msg); 207 *keysp = xcalloc(nkeys, sizeof(Key *)); 208 for (i = 0; i < nkeys; i++) { 209 blob = buffer_get_string(&msg, &blen); 210 free(buffer_get_string(&msg, NULL)); 211 k = key_from_blob(blob, blen); 212 wrap_key(k->rsa); 213 (*keysp)[i] = k; 214 free(blob); 215 } 216 } else { 217 nkeys = -1; 218 } 219 buffer_free(&msg); 220 return (nkeys); 221 } 222 223 int 224 pkcs11_del_provider(char *name) 225 { 226 int ret = -1; 227 Buffer msg; 228 229 buffer_init(&msg); 230 buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); 231 buffer_put_cstring(&msg, name); 232 buffer_put_cstring(&msg, ""); 233 send_msg(&msg); 234 buffer_clear(&msg); 235 236 if (recv_msg(&msg) == SSH_AGENT_SUCCESS) 237 ret = 0; 238 buffer_free(&msg); 239 return (ret); 240 } 241 242 #endif /* ENABLE_PKCS11 */ 243
