1 /* $NetBSD: ssh-pkcs11-client.c,v 1.6 2015/04/03 23:58:19 christos Exp $ */ 2 /* $OpenBSD: ssh-pkcs11-client.c,v 1.5 2014/06/24 01:13:21 djm Exp $ */ 3 /* 4 * Copyright (c) 2010 Markus Friedl. All rights reserved. 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 #include "includes.h" 19 __RCSID("$NetBSD: ssh-pkcs11-client.c,v 1.6 2015/04/03 23:58:19 christos Exp $"); 20 21 #include <sys/types.h> 22 #include <sys/time.h> 23 #include <sys/socket.h> 24 25 #include <stdarg.h> 26 #include <string.h> 27 #include <unistd.h> 28 #include <errno.h> 29 30 #include <openssl/rsa.h> 31 32 #include "pathnames.h" 33 #include "xmalloc.h" 34 #include "buffer.h" 35 #include "log.h" 36 #include "misc.h" 37 #include "key.h" 38 #include "authfd.h" 39 #include "atomicio.h" 40 #include "ssh-pkcs11.h" 41 42 /* borrows code from sftp-server and ssh-agent */ 43 44 int fd = -1; 45 pid_t pid = -1; 46 47 static void 48 send_msg(Buffer *m) 49 { 50 u_char buf[4]; 51 int mlen = buffer_len(m); 52 53 put_u32(buf, mlen); 54 if (atomicio(vwrite, fd, buf, 4) != 4 || 55 atomicio(vwrite, fd, buffer_ptr(m), 56 buffer_len(m)) != buffer_len(m)) 57 error("write to helper failed"); 58 buffer_consume(m, mlen); 59 } 60 61 static int 62 recv_msg(Buffer *m) 63 { 64 u_int l, len; 65 u_char buf[1024]; 66 67 if ((len = atomicio(read, fd, buf, 4)) != 4) { 68 error("read from helper failed: %u", len); 69 return (0); /* XXX */ 70 } 71 len = get_u32(buf); 72 if (len > 256 * 1024) 73 fatal("response too long: %u", len); 74 /* read len bytes into m */ 75 buffer_clear(m); 76 while (len > 0) { 77 l = len; 78 if (l > sizeof(buf)) 79 l = sizeof(buf); 80 if (atomicio(read, fd, buf, l) != l) { 81 error("response from helper failed."); 82 return (0); /* XXX */ 83 } 84 buffer_append(m, buf, l); 85 len -= l; 86 } 87 return (buffer_get_char(m)); 88 } 89 90 int 91 pkcs11_init(int interactive) 92 { 93 return (0); 94 } 95 96 void 97 pkcs11_terminate(void) 98 { 99 close(fd); 100 } 101 102 static int 103 pkcs11_rsa_private_encrypt(int flen, const u_char *from, u_char *to, RSA *rsa, 104 int padding) 105 { 106 Key key; 107 u_char *blob, *signature = NULL; 108 u_int blen, slen = 0; 109 int ret = -1; 110 Buffer msg; 111 112 if (padding != RSA_PKCS1_PADDING) 113 return (-1); 114 key.type = KEY_RSA; 115 key.rsa = rsa; 116 if (key_to_blob(&key, &blob, &blen) == 0) 117 return -1; 118 buffer_init(&msg); 119 buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST); 120 buffer_put_string(&msg, blob, blen); 121 buffer_put_string(&msg, from, flen); 122 buffer_put_int(&msg, 0); 123 free(blob); 124 send_msg(&msg); 125 buffer_clear(&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 free(signature); 134 } 135 buffer_free(&msg); 136 return (ret); 137 } 138 139 /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ 140 static int 141 wrap_key(RSA *rsa) 142 { 143 static RSA_METHOD helper_rsa; 144 145 memcpy(&helper_rsa, RSA_get_default_method(), sizeof(helper_rsa)); 146 helper_rsa.name = "ssh-pkcs11-helper"; 147 helper_rsa.rsa_priv_enc = pkcs11_rsa_private_encrypt; 148 RSA_set_method(rsa, &helper_rsa); 149 return (0); 150 } 151 152 static int 153 pkcs11_start_helper(void) 154 { 155 int pair[2]; 156 157 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 158 error("socketpair: %s", strerror(errno)); 159 return (-1); 160 } 161 if ((pid = fork()) == -1) { 162 error("fork: %s", strerror(errno)); 163 return (-1); 164 } else if (pid == 0) { 165 if ((dup2(pair[1], STDIN_FILENO) == -1) || 166 (dup2(pair[1], STDOUT_FILENO) == -1)) { 167 fprintf(stderr, "dup2: %s\n", strerror(errno)); 168 _exit(1); 169 } 170 close(pair[0]); 171 close(pair[1]); 172 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 173 (char *) 0); 174 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 175 strerror(errno)); 176 _exit(1); 177 } 178 close(pair[1]); 179 fd = pair[0]; 180 return (0); 181 } 182 183 int 184 pkcs11_add_provider(char *name, char *pin, Key ***keysp) 185 { 186 Key *k; 187 int i, nkeys; 188 u_char *blob; 189 u_int blen; 190 Buffer msg; 191 192 if (fd < 0 && pkcs11_start_helper() < 0) 193 return (-1); 194 195 buffer_init(&msg); 196 buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); 197 buffer_put_cstring(&msg, name); 198 buffer_put_cstring(&msg, pin); 199 send_msg(&msg); 200 buffer_clear(&msg); 201 202 if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 203 nkeys = buffer_get_int(&msg); 204 *keysp = xcalloc(nkeys, sizeof(Key *)); 205 for (i = 0; i < nkeys; i++) { 206 blob = buffer_get_string(&msg, &blen); 207 free(buffer_get_string(&msg, NULL)); 208 k = key_from_blob(blob, blen); 209 wrap_key(k->rsa); 210 (*keysp)[i] = k; 211 free(blob); 212 } 213 } else { 214 nkeys = -1; 215 } 216 buffer_free(&msg); 217 return (nkeys); 218 } 219 220 int 221 pkcs11_del_provider(char *name) 222 { 223 int ret = -1; 224 Buffer msg; 225 226 buffer_init(&msg); 227 buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); 228 buffer_put_cstring(&msg, name); 229 buffer_put_cstring(&msg, ""); 230 send_msg(&msg); 231 buffer_clear(&msg); 232 233 if (recv_msg(&msg) == SSH_AGENT_SUCCESS) 234 ret = 0; 235 buffer_free(&msg); 236 return (ret); 237 } 238