1263970Sdes/* $OpenBSD: ssh-pkcs11-helper.c,v 1.7 2013/12/02 02:56:17 djm Exp $ */ 2204861Sdes/* 3204861Sdes * Copyright (c) 2010 Markus Friedl. All rights reserved. 4204861Sdes * 5204861Sdes * Permission to use, copy, modify, and distribute this software for any 6204861Sdes * purpose with or without fee is hereby granted, provided that the above 7204861Sdes * copyright notice and this permission notice appear in all copies. 8204861Sdes * 9204861Sdes * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10204861Sdes * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11204861Sdes * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12204861Sdes * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13204861Sdes * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14204861Sdes * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15204861Sdes * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16204861Sdes */ 17204861Sdes 18204861Sdes#include "includes.h" 19204861Sdes 20204861Sdes#include <sys/types.h> 21204861Sdes#ifdef HAVE_SYS_TIME_H 22204861Sdes# include <sys/time.h> 23204861Sdes#endif 24204861Sdes 25204861Sdes#include "openbsd-compat/sys-queue.h" 26204861Sdes 27204861Sdes#include <stdarg.h> 28204861Sdes#include <string.h> 29204861Sdes#include <unistd.h> 30204861Sdes#include <errno.h> 31204861Sdes 32204861Sdes#include "xmalloc.h" 33204861Sdes#include "buffer.h" 34204861Sdes#include "log.h" 35204861Sdes#include "misc.h" 36204861Sdes#include "key.h" 37204861Sdes#include "authfd.h" 38204861Sdes#include "ssh-pkcs11.h" 39204861Sdes 40207319Sdes#ifdef ENABLE_PKCS11 41207319Sdes 42204861Sdes/* borrows code from sftp-server and ssh-agent */ 43204861Sdes 44204861Sdesstruct pkcs11_keyinfo { 45204861Sdes Key *key; 46204861Sdes char *providername; 47204861Sdes TAILQ_ENTRY(pkcs11_keyinfo) next; 48204861Sdes}; 49204861Sdes 50204861SdesTAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist; 51204861Sdes 52204861Sdes#define MAX_MSG_LENGTH 10240 /*XXX*/ 53204861Sdes 54204861Sdes/* helper */ 55204861Sdes#define get_int() buffer_get_int(&iqueue); 56204861Sdes#define get_string(lenp) buffer_get_string(&iqueue, lenp); 57204861Sdes 58204861Sdes/* input and output queue */ 59204861SdesBuffer iqueue; 60204861SdesBuffer oqueue; 61204861Sdes 62204861Sdesstatic void 63204861Sdesadd_key(Key *k, char *name) 64204861Sdes{ 65204861Sdes struct pkcs11_keyinfo *ki; 66204861Sdes 67204861Sdes ki = xcalloc(1, sizeof(*ki)); 68204861Sdes ki->providername = xstrdup(name); 69204861Sdes ki->key = k; 70204861Sdes TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next); 71204861Sdes} 72204861Sdes 73204861Sdesstatic void 74204861Sdesdel_keys_by_name(char *name) 75204861Sdes{ 76204861Sdes struct pkcs11_keyinfo *ki, *nxt; 77204861Sdes 78204861Sdes for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) { 79204861Sdes nxt = TAILQ_NEXT(ki, next); 80204861Sdes if (!strcmp(ki->providername, name)) { 81204861Sdes TAILQ_REMOVE(&pkcs11_keylist, ki, next); 82263970Sdes free(ki->providername); 83204861Sdes key_free(ki->key); 84204861Sdes free(ki); 85204861Sdes } 86204861Sdes } 87204861Sdes} 88204861Sdes 89204861Sdes/* lookup matching 'private' key */ 90204861Sdesstatic Key * 91204861Sdeslookup_key(Key *k) 92204861Sdes{ 93204861Sdes struct pkcs11_keyinfo *ki; 94204861Sdes 95204861Sdes TAILQ_FOREACH(ki, &pkcs11_keylist, next) { 96204861Sdes debug("check %p %s", ki, ki->providername); 97204861Sdes if (key_equal(k, ki->key)) 98204861Sdes return (ki->key); 99204861Sdes } 100204861Sdes return (NULL); 101204861Sdes} 102204861Sdes 103204861Sdesstatic void 104204861Sdessend_msg(Buffer *m) 105204861Sdes{ 106204861Sdes int mlen = buffer_len(m); 107204861Sdes 108204861Sdes buffer_put_int(&oqueue, mlen); 109204861Sdes buffer_append(&oqueue, buffer_ptr(m), mlen); 110204861Sdes buffer_consume(m, mlen); 111204861Sdes} 112204861Sdes 113204861Sdesstatic void 114204861Sdesprocess_add(void) 115204861Sdes{ 116204861Sdes char *name, *pin; 117204861Sdes Key **keys; 118204861Sdes int i, nkeys; 119204861Sdes u_char *blob; 120204861Sdes u_int blen; 121204861Sdes Buffer msg; 122204861Sdes 123204861Sdes buffer_init(&msg); 124204861Sdes name = get_string(NULL); 125204861Sdes pin = get_string(NULL); 126204861Sdes if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) { 127204861Sdes buffer_put_char(&msg, SSH2_AGENT_IDENTITIES_ANSWER); 128204861Sdes buffer_put_int(&msg, nkeys); 129204861Sdes for (i = 0; i < nkeys; i++) { 130263970Sdes if (key_to_blob(keys[i], &blob, &blen) == 0) 131263970Sdes continue; 132204861Sdes buffer_put_string(&msg, blob, blen); 133204861Sdes buffer_put_cstring(&msg, name); 134263970Sdes free(blob); 135204861Sdes add_key(keys[i], name); 136204861Sdes } 137263970Sdes free(keys); 138204861Sdes } else { 139204861Sdes buffer_put_char(&msg, SSH_AGENT_FAILURE); 140204861Sdes } 141263970Sdes free(pin); 142263970Sdes free(name); 143204861Sdes send_msg(&msg); 144204861Sdes buffer_free(&msg); 145204861Sdes} 146204861Sdes 147204861Sdesstatic void 148204861Sdesprocess_del(void) 149204861Sdes{ 150204861Sdes char *name, *pin; 151204861Sdes Buffer msg; 152204861Sdes 153204861Sdes buffer_init(&msg); 154204861Sdes name = get_string(NULL); 155204861Sdes pin = get_string(NULL); 156204861Sdes del_keys_by_name(name); 157204861Sdes if (pkcs11_del_provider(name) == 0) 158204861Sdes buffer_put_char(&msg, SSH_AGENT_SUCCESS); 159204861Sdes else 160204861Sdes buffer_put_char(&msg, SSH_AGENT_FAILURE); 161263970Sdes free(pin); 162263970Sdes free(name); 163204861Sdes send_msg(&msg); 164204861Sdes buffer_free(&msg); 165204861Sdes} 166204861Sdes 167204861Sdesstatic void 168204861Sdesprocess_sign(void) 169204861Sdes{ 170204861Sdes u_char *blob, *data, *signature = NULL; 171204861Sdes u_int blen, dlen, slen = 0; 172247485Sdes int ok = -1, ret; 173204861Sdes Key *key, *found; 174204861Sdes Buffer msg; 175204861Sdes 176204861Sdes blob = get_string(&blen); 177204861Sdes data = get_string(&dlen); 178247485Sdes (void)get_int(); /* XXX ignore flags */ 179204861Sdes 180204861Sdes if ((key = key_from_blob(blob, blen)) != NULL) { 181204861Sdes if ((found = lookup_key(key)) != NULL) { 182204861Sdes slen = RSA_size(key->rsa); 183204861Sdes signature = xmalloc(slen); 184204861Sdes if ((ret = RSA_private_encrypt(dlen, data, signature, 185204861Sdes found->rsa, RSA_PKCS1_PADDING)) != -1) { 186204861Sdes slen = ret; 187204861Sdes ok = 0; 188204861Sdes } 189204861Sdes } 190204861Sdes key_free(key); 191204861Sdes } 192204861Sdes buffer_init(&msg); 193204861Sdes if (ok == 0) { 194204861Sdes buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); 195204861Sdes buffer_put_string(&msg, signature, slen); 196204861Sdes } else { 197204861Sdes buffer_put_char(&msg, SSH_AGENT_FAILURE); 198204861Sdes } 199263970Sdes free(data); 200263970Sdes free(blob); 201263970Sdes free(signature); 202204861Sdes send_msg(&msg); 203204861Sdes buffer_free(&msg); 204204861Sdes} 205204861Sdes 206204861Sdesstatic void 207204861Sdesprocess(void) 208204861Sdes{ 209204861Sdes u_int msg_len; 210204861Sdes u_int buf_len; 211204861Sdes u_int consumed; 212204861Sdes u_int type; 213204861Sdes u_char *cp; 214204861Sdes 215204861Sdes buf_len = buffer_len(&iqueue); 216204861Sdes if (buf_len < 5) 217204861Sdes return; /* Incomplete message. */ 218204861Sdes cp = buffer_ptr(&iqueue); 219204861Sdes msg_len = get_u32(cp); 220204861Sdes if (msg_len > MAX_MSG_LENGTH) { 221204861Sdes error("bad message len %d", msg_len); 222204861Sdes cleanup_exit(11); 223204861Sdes } 224204861Sdes if (buf_len < msg_len + 4) 225204861Sdes return; 226204861Sdes buffer_consume(&iqueue, 4); 227204861Sdes buf_len -= 4; 228204861Sdes type = buffer_get_char(&iqueue); 229204861Sdes switch (type) { 230204861Sdes case SSH_AGENTC_ADD_SMARTCARD_KEY: 231204861Sdes debug("process_add"); 232204861Sdes process_add(); 233204861Sdes break; 234204861Sdes case SSH_AGENTC_REMOVE_SMARTCARD_KEY: 235204861Sdes debug("process_del"); 236204861Sdes process_del(); 237204861Sdes break; 238204861Sdes case SSH2_AGENTC_SIGN_REQUEST: 239204861Sdes debug("process_sign"); 240204861Sdes process_sign(); 241204861Sdes break; 242204861Sdes default: 243204861Sdes error("Unknown message %d", type); 244204861Sdes break; 245204861Sdes } 246204861Sdes /* discard the remaining bytes from the current packet */ 247204861Sdes if (buf_len < buffer_len(&iqueue)) { 248204861Sdes error("iqueue grew unexpectedly"); 249204861Sdes cleanup_exit(255); 250204861Sdes } 251204861Sdes consumed = buf_len - buffer_len(&iqueue); 252204861Sdes if (msg_len < consumed) { 253204861Sdes error("msg_len %d < consumed %d", msg_len, consumed); 254204861Sdes cleanup_exit(255); 255204861Sdes } 256204861Sdes if (msg_len > consumed) 257204861Sdes buffer_consume(&iqueue, msg_len - consumed); 258204861Sdes} 259204861Sdes 260204861Sdesvoid 261204861Sdescleanup_exit(int i) 262204861Sdes{ 263204861Sdes /* XXX */ 264204861Sdes _exit(i); 265204861Sdes} 266204861Sdes 267204861Sdesint 268204861Sdesmain(int argc, char **argv) 269204861Sdes{ 270204861Sdes fd_set *rset, *wset; 271204861Sdes int in, out, max, log_stderr = 0; 272204861Sdes ssize_t len, olen, set_size; 273204861Sdes SyslogFacility log_facility = SYSLOG_FACILITY_AUTH; 274204861Sdes LogLevel log_level = SYSLOG_LEVEL_ERROR; 275204861Sdes char buf[4*4096]; 276204861Sdes 277204861Sdes extern char *__progname; 278204861Sdes 279204861Sdes TAILQ_INIT(&pkcs11_keylist); 280204861Sdes pkcs11_init(0); 281204861Sdes 282204861Sdes seed_rng(); 283204861Sdes __progname = ssh_get_progname(argv[0]); 284204861Sdes 285204861Sdes log_init(__progname, log_level, log_facility, log_stderr); 286204861Sdes 287204861Sdes in = STDIN_FILENO; 288204861Sdes out = STDOUT_FILENO; 289204861Sdes 290204861Sdes max = 0; 291204861Sdes if (in > max) 292204861Sdes max = in; 293204861Sdes if (out > max) 294204861Sdes max = out; 295204861Sdes 296204861Sdes buffer_init(&iqueue); 297204861Sdes buffer_init(&oqueue); 298204861Sdes 299204861Sdes set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask); 300204861Sdes rset = (fd_set *)xmalloc(set_size); 301204861Sdes wset = (fd_set *)xmalloc(set_size); 302204861Sdes 303204861Sdes for (;;) { 304204861Sdes memset(rset, 0, set_size); 305204861Sdes memset(wset, 0, set_size); 306204861Sdes 307204861Sdes /* 308204861Sdes * Ensure that we can read a full buffer and handle 309204861Sdes * the worst-case length packet it can generate, 310204861Sdes * otherwise apply backpressure by stopping reads. 311204861Sdes */ 312204861Sdes if (buffer_check_alloc(&iqueue, sizeof(buf)) && 313204861Sdes buffer_check_alloc(&oqueue, MAX_MSG_LENGTH)) 314204861Sdes FD_SET(in, rset); 315204861Sdes 316204861Sdes olen = buffer_len(&oqueue); 317204861Sdes if (olen > 0) 318204861Sdes FD_SET(out, wset); 319204861Sdes 320204861Sdes if (select(max+1, rset, wset, NULL, NULL) < 0) { 321204861Sdes if (errno == EINTR) 322204861Sdes continue; 323204861Sdes error("select: %s", strerror(errno)); 324204861Sdes cleanup_exit(2); 325204861Sdes } 326204861Sdes 327204861Sdes /* copy stdin to iqueue */ 328204861Sdes if (FD_ISSET(in, rset)) { 329204861Sdes len = read(in, buf, sizeof buf); 330204861Sdes if (len == 0) { 331204861Sdes debug("read eof"); 332204861Sdes cleanup_exit(0); 333204861Sdes } else if (len < 0) { 334204861Sdes error("read: %s", strerror(errno)); 335204861Sdes cleanup_exit(1); 336204861Sdes } else { 337204861Sdes buffer_append(&iqueue, buf, len); 338204861Sdes } 339204861Sdes } 340204861Sdes /* send oqueue to stdout */ 341204861Sdes if (FD_ISSET(out, wset)) { 342204861Sdes len = write(out, buffer_ptr(&oqueue), olen); 343204861Sdes if (len < 0) { 344204861Sdes error("write: %s", strerror(errno)); 345204861Sdes cleanup_exit(1); 346204861Sdes } else { 347204861Sdes buffer_consume(&oqueue, len); 348204861Sdes } 349204861Sdes } 350204861Sdes 351204861Sdes /* 352204861Sdes * Process requests from client if we can fit the results 353204861Sdes * into the output buffer, otherwise stop processing input 354204861Sdes * and let the output queue drain. 355204861Sdes */ 356204861Sdes if (buffer_check_alloc(&oqueue, MAX_MSG_LENGTH)) 357204861Sdes process(); 358204861Sdes } 359204861Sdes} 360204861Sdes#else /* ENABLE_PKCS11 */ 361204861Sdesint 362204861Sdesmain(int argc, char **argv) 363204861Sdes{ 364204861Sdes extern char *__progname; 365204861Sdes 366204861Sdes __progname = ssh_get_progname(argv[0]); 367204861Sdes log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0); 368204861Sdes fatal("PKCS#11 support disabled at compile time"); 369204861Sdes} 370204861Sdes#endif /* ENABLE_PKCS11 */ 371