1 /* $NetBSD: ssh-pkcs11-client.c,v 1.12 2018/04/06 18:59:00 christos Exp $ */ 2 /* $OpenBSD: ssh-pkcs11-client.c,v 1.8 2018/02/05 05:37:46 tb 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 1.12 2018/04/06 18:59:00 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 if (fd >= 0) 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 struct sshkey key; /* XXX */ 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 free(blob); 125 send_msg(&msg); 126 buffer_clear(&msg); 127 128 if (recv_msg(&msg) == SSH2_AGENT_SIGN_RESPONSE) { 129 signature = buffer_get_string(&msg, &slen); 130 if (slen <= (u_int)RSA_size(rsa)) { 131 memcpy(to, signature, slen); 132 ret = slen; 133 } 134 free(signature); 135 } 136 buffer_free(&msg); 137 return (ret); 138 } 139 140 /* redirect the private key encrypt operation to the ssh-pkcs11-helper */ 141 static int 142 wrap_key(RSA *rsa) 143 { 144 static RSA_METHOD *helper_rsa; 145 146 if ((helper_rsa = RSA_meth_dup(RSA_get_default_method())) == NULL) 147 return (-1); /* XXX but caller isn't checking */ 148 RSA_meth_set1_name(helper_rsa, "ssh-pkcs11-helper"); 149 RSA_meth_set_priv_enc(helper_rsa, pkcs11_rsa_private_encrypt); 150 RSA_set_method(rsa, helper_rsa); 151 return (0); 152 } 153 154 static int 155 pkcs11_start_helper(void) 156 { 157 int pair[2]; 158 159 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) == -1) { 160 error("socketpair: %s", strerror(errno)); 161 return (-1); 162 } 163 if ((pid = fork()) == -1) { 164 error("fork: %s", strerror(errno)); 165 return (-1); 166 } else if (pid == 0) { 167 if ((dup2(pair[1], STDIN_FILENO) == -1) || 168 (dup2(pair[1], STDOUT_FILENO) == -1)) { 169 fprintf(stderr, "dup2: %s\n", strerror(errno)); 170 _exit(1); 171 } 172 close(pair[0]); 173 close(pair[1]); 174 execlp(_PATH_SSH_PKCS11_HELPER, _PATH_SSH_PKCS11_HELPER, 175 (char *)NULL); 176 fprintf(stderr, "exec: %s: %s\n", _PATH_SSH_PKCS11_HELPER, 177 strerror(errno)); 178 _exit(1); 179 } 180 close(pair[1]); 181 fd = pair[0]; 182 return (0); 183 } 184 185 int 186 pkcs11_add_provider(char *name, char *pin, Key ***keysp) 187 { 188 struct sshkey *k; 189 int i, nkeys; 190 u_char *blob; 191 u_int blen; 192 Buffer msg; 193 194 if (fd < 0 && pkcs11_start_helper() < 0) 195 return (-1); 196 197 buffer_init(&msg); 198 buffer_put_char(&msg, SSH_AGENTC_ADD_SMARTCARD_KEY); 199 buffer_put_cstring(&msg, name); 200 buffer_put_cstring(&msg, pin); 201 send_msg(&msg); 202 buffer_clear(&msg); 203 204 if (recv_msg(&msg) == SSH2_AGENT_IDENTITIES_ANSWER) { 205 nkeys = buffer_get_int(&msg); 206 *keysp = xcalloc(nkeys, sizeof(Key *)); 207 for (i = 0; i < nkeys; i++) { 208 blob = buffer_get_string(&msg, &blen); 209 free(buffer_get_string(&msg, NULL)); 210 k = key_from_blob(blob, blen); 211 wrap_key(k->rsa); 212 (*keysp)[i] = k; 213 free(blob); 214 } 215 } else { 216 nkeys = -1; 217 } 218 buffer_free(&msg); 219 return (nkeys); 220 } 221 222 int 223 pkcs11_del_provider(char *name) 224 { 225 int ret = -1; 226 Buffer msg; 227 228 buffer_init(&msg); 229 buffer_put_char(&msg, SSH_AGENTC_REMOVE_SMARTCARD_KEY); 230 buffer_put_cstring(&msg, name); 231 buffer_put_cstring(&msg, ""); 232 send_msg(&msg); 233 buffer_clear(&msg); 234 235 if (recv_msg(&msg) == SSH_AGENT_SUCCESS) 236 ret = 0; 237 buffer_free(&msg); 238 return (ret); 239 } 240