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 <sys/types.h> 19 #include <sys/time.h> 20 #include <sys/socket.h> 21 22 #include <stdarg.h> 23 #include <string.h> 24 #include <unistd.h> 25 #include <errno.h> 26 27 #include <openssl/rsa.h> 28 29 #include "pathnames.h" 30 #include "xmalloc.h" 31 #include "buffer.h" 32 #include "log.h" 33 #include "misc.h" 34 #include "key.h" 35 #include "authfd.h" 36 #include "atomicio.h" 37 #include "ssh-pkcs11.h" 38 39 /* borrows code from sftp-server and ssh-agent */ 40 41 int fd = -1; 42 pid_t pid = -1; 43 44 static void 45 send_msg(Buffer *m) 46 { 47 u_char buf[4]; 48 int mlen = buffer_len(m); 49 50 put_u32(buf, mlen); 51 if (atomicio(vwrite, fd, buf, 4) != 4 || 52 atomicio(vwrite, fd, buffer_ptr(m), 53 buffer_len(m)) != buffer_len(m)) 54 error("write to helper failed"); 55 buffer_consume(m, mlen); 56 } 57 58 static int 59 recv_msg(Buffer *m) 60 { 61 u_int l, len; 62 u_char buf[1024]; 63 64 if ((len = atomicio(read, fd, buf, 4)) != 4) { 65 error("read from helper failed: %u", len); 66 return (0); /* XXX */ 67 } 68 len = get_u32(buf); 69 if (len > 256 * 1024) 70 fatal("response too long: %u", len); 71 /* read len bytes into m */ 72 buffer_clear(m); 73 while (len > 0) { 74 l = len; 75 if (l > sizeof(buf)) 76 l = sizeof(buf); 77 if (atomicio(read, fd, buf, l) != l) { 78 error("response from helper failed."); 79 return (0); /* XXX */ 80 } 81 buffer_append(m, buf, l); 82 len -= l; 83 } 84 return (buffer_get_char(m)); 85 } 86 87 int 88 pkcs11_init(int interactive) 89 { 90 return (0); 91 } 92 93 void 94 pkcs11_terminate(void) 95 { 96 close(fd); 97 } 98 99 static int 100 pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 101 int padding) 102 { 103 Key key; 104 u_char *blob, *signature = NULL; 105 u_int blen, slen = 0; 106 int ret = -1; 107 Buffer msg; 108 109 if (padding != RSA_PKCS1_PADDING) 110 return (-1); 111 key.type = KEY_RSA; 112 key.rsa = rsa; 113 if (key_to_blob(&key, &blob, &blen) == 0) 114 return -1; 115 buffer_init(&msg); 116 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST); 117 buffer_put_string(&msg, blob, blen); 118 buffer_put_string(&msg, from, flen); 119 buffer_put_int(&msg, 0); 120 free(blob); 121 send_msg(&msg); 122 buffer_clear(&msg); 123 124 if (recv_msg(&msg) == SSH2_AGENT_SIGN_RESPONSE) { 125 signature = buffer_get_string(&msg, &slen); 126 if (slen <= (u_int)RSA_size(rsa)) { 127 memcpy(to, signature, slen); 128 ret = slen; 129 } 130 free(signature); 131 } 132 buffer_free(&msg); 133 return (ret); 134 } 135 136 /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ 137 static int 138 wrap_key(RSA *rsa) 139 { 140 static RSA_METHOD helper_rsa; 141 142 memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); 143 helper_rsa.name = "ssh-pkcs11-helper"; 144 helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; 145 RSA_set_method(rsa, &helper_rsa); 146 return (0); 147 } 148 149 static int 150 pkcs11_start_helper(void) 151 { 152 int pair[2]; 153 154 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 155 error("socketpair: %s", strerror(errno)); 156 return (-1); 157 } 158 if ((pid = fork()) == -1) { 159 error("fork: %s", strerror(errno)); 160 return (-1); 161 } else if (pid == 0) { 162 if ((dup2(pair[1], STDIN_FILENO) == -1) || 163 (dup2(pair[1], STDOUT_FILENO) == -1)) { 164 fprintf(stderr, "dup2: %s\n", strerror(errno)); 165 _exit(1); 166 } 167 close(pair[0]); 168 close(pair[1]); 169 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 170 (char *) 0); 171 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 172 strerror(errno)); 173 _exit(1); 174 } 175 close(pair[1]); 176 fd = pair[0]; 177 return (0); 178 } 179 180 int 181 pkcs11_add_provider(char *name, char *pin, Key ***keysp) 182 { 183 Key *k; 184 int i, nkeys; 185 u_char *blob; 186 u_int blen; 187 Buffer msg; 188 189 if (fd < 0 && pkcs11_start_helper() < 0) 190 return (-1); 191 192 buffer_init(&msg); 193 buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); 194 buffer_put_cstring(&msg, name); 195 buffer_put_cstring(&msg, pin); 196 send_msg(&msg); 197 buffer_clear(&msg); 198 199 if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 200 nkeys = buffer_get_int(&msg); 201 *keysp = xcalloc(nkeys, sizeof(Key *)); 202 for (i = 0; i < nkeys; i++) { 203 blob = buffer_get_string(&msg, &blen); 204 free(buffer_get_string(&msg, NULL)); 205 k = key_from_blob(blob, blen); 206 wrap_key(k->rsa); 207 (*keysp)[i] = k; 208 free(blob); 209 } 210 } else { 211 nkeys = -1; 212 } 213 buffer_free(&msg); 214 return (nkeys); 215 } 216 217 int 218 pkcs11_del_provider(char *name) 219 { 220 int ret = -1; 221 Buffer msg; 222 223 buffer_init(&msg); 224 buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); 225 buffer_put_cstring(&msg, name); 226 buffer_put_cstring(&msg, ""); 227 send_msg(&msg); 228 buffer_clear(&msg); 229 230 if (recv_msg(&msg) == SSH_AGENT_SUCCESS) 231 ret = 0; 232 buffer_free(&msg); 233 return (ret); 234 } 235