373 lines
7.9 KiB
C
373 lines
7.9 KiB
C
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/* $OpenBSD: ssh-pkcs11-helper.c,v 1.3 2010/02/24 06:12:53 djm Exp $ */
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/*
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* Copyright (c) 2010 Markus Friedl. All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#ifdef ENABLE_PKCS11
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#include <sys/types.h>
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#ifdef HAVE_SYS_TIME_H
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# include <sys/time.h>
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#endif
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#include "openbsd-compat/sys-queue.h"
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#include <stdarg.h>
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#include <string.h>
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#include <unistd.h>
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#include <errno.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "log.h"
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#include "misc.h"
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#include "key.h"
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#include "authfd.h"
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#include "ssh-pkcs11.h"
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/* borrows code from sftp-server and ssh-agent */
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struct pkcs11_keyinfo {
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Key *key;
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char *providername;
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TAILQ_ENTRY(pkcs11_keyinfo) next;
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};
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TAILQ_HEAD(, pkcs11_keyinfo) pkcs11_keylist;
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#define MAX_MSG_LENGTH 10240 /*XXX*/
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/* helper */
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#define get_int() buffer_get_int(&iqueue);
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#define get_string(lenp) buffer_get_string(&iqueue, lenp);
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/* input and output queue */
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Buffer iqueue;
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Buffer oqueue;
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static void
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add_key(Key *k, char *name)
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{
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struct pkcs11_keyinfo *ki;
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ki = xcalloc(1, sizeof(*ki));
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ki->providername = xstrdup(name);
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ki->key = k;
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TAILQ_INSERT_TAIL(&pkcs11_keylist, ki, next);
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}
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static void
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del_keys_by_name(char *name)
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{
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struct pkcs11_keyinfo *ki, *nxt;
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for (ki = TAILQ_FIRST(&pkcs11_keylist); ki; ki = nxt) {
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nxt = TAILQ_NEXT(ki, next);
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if (!strcmp(ki->providername, name)) {
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TAILQ_REMOVE(&pkcs11_keylist, ki, next);
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xfree(ki->providername);
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key_free(ki->key);
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free(ki);
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}
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}
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}
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/* lookup matching 'private' key */
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static Key *
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lookup_key(Key *k)
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{
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struct pkcs11_keyinfo *ki;
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TAILQ_FOREACH(ki, &pkcs11_keylist, next) {
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debug("check %p %s", ki, ki->providername);
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if (key_equal(k, ki->key))
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return (ki->key);
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}
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return (NULL);
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}
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static void
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send_msg(Buffer *m)
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{
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int mlen = buffer_len(m);
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buffer_put_int(&oqueue, mlen);
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buffer_append(&oqueue, buffer_ptr(m), mlen);
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buffer_consume(m, mlen);
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}
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static void
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process_add(void)
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{
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char *name, *pin;
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Key **keys;
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int i, nkeys;
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u_char *blob;
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u_int blen;
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Buffer msg;
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buffer_init(&msg);
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name = get_string(NULL);
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pin = get_string(NULL);
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if ((nkeys = pkcs11_add_provider(name, pin, &keys)) > 0) {
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buffer_put_char(&msg, SSH2_AGENT_IDENTITIES_ANSWER);
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buffer_put_int(&msg, nkeys);
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for (i = 0; i < nkeys; i++) {
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key_to_blob(keys[i], &blob, &blen);
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buffer_put_string(&msg, blob, blen);
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buffer_put_cstring(&msg, name);
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xfree(blob);
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add_key(keys[i], name);
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}
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xfree(keys);
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} else {
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buffer_put_char(&msg, SSH_AGENT_FAILURE);
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}
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xfree(pin);
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xfree(name);
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send_msg(&msg);
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buffer_free(&msg);
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}
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static void
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process_del(void)
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{
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char *name, *pin;
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Buffer msg;
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buffer_init(&msg);
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name = get_string(NULL);
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pin = get_string(NULL);
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del_keys_by_name(name);
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if (pkcs11_del_provider(name) == 0)
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buffer_put_char(&msg, SSH_AGENT_SUCCESS);
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else
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buffer_put_char(&msg, SSH_AGENT_FAILURE);
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xfree(pin);
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xfree(name);
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send_msg(&msg);
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buffer_free(&msg);
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}
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static void
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process_sign(void)
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{
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u_char *blob, *data, *signature = NULL;
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u_int blen, dlen, slen = 0;
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int ok = -1, flags, ret;
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Key *key, *found;
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Buffer msg;
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blob = get_string(&blen);
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data = get_string(&dlen);
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flags = get_int(); /* XXX ignore */
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if ((key = key_from_blob(blob, blen)) != NULL) {
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if ((found = lookup_key(key)) != NULL) {
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slen = RSA_size(key->rsa);
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signature = xmalloc(slen);
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if ((ret = RSA_private_encrypt(dlen, data, signature,
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found->rsa, RSA_PKCS1_PADDING)) != -1) {
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slen = ret;
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ok = 0;
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}
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}
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key_free(key);
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}
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buffer_init(&msg);
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if (ok == 0) {
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buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE);
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buffer_put_string(&msg, signature, slen);
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} else {
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buffer_put_char(&msg, SSH_AGENT_FAILURE);
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}
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xfree(data);
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xfree(blob);
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if (signature != NULL)
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xfree(signature);
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send_msg(&msg);
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buffer_free(&msg);
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}
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static void
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process(void)
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{
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u_int msg_len;
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u_int buf_len;
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u_int consumed;
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u_int type;
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u_char *cp;
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buf_len = buffer_len(&iqueue);
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if (buf_len < 5)
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return; /* Incomplete message. */
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cp = buffer_ptr(&iqueue);
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msg_len = get_u32(cp);
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if (msg_len > MAX_MSG_LENGTH) {
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error("bad message len %d", msg_len);
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cleanup_exit(11);
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}
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if (buf_len < msg_len + 4)
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return;
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buffer_consume(&iqueue, 4);
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buf_len -= 4;
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type = buffer_get_char(&iqueue);
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switch (type) {
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case SSH_AGENTC_ADD_SMARTCARD_KEY:
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debug("process_add");
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process_add();
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break;
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case SSH_AGENTC_REMOVE_SMARTCARD_KEY:
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debug("process_del");
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process_del();
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break;
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case SSH2_AGENTC_SIGN_REQUEST:
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debug("process_sign");
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process_sign();
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break;
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default:
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error("Unknown message %d", type);
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break;
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}
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/* discard the remaining bytes from the current packet */
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if (buf_len < buffer_len(&iqueue)) {
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error("iqueue grew unexpectedly");
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cleanup_exit(255);
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}
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consumed = buf_len - buffer_len(&iqueue);
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if (msg_len < consumed) {
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error("msg_len %d < consumed %d", msg_len, consumed);
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cleanup_exit(255);
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}
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if (msg_len > consumed)
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buffer_consume(&iqueue, msg_len - consumed);
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}
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void
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cleanup_exit(int i)
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{
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/* XXX */
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_exit(i);
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}
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int
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main(int argc, char **argv)
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{
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fd_set *rset, *wset;
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int in, out, max, log_stderr = 0;
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ssize_t len, olen, set_size;
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SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
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LogLevel log_level = SYSLOG_LEVEL_ERROR;
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char buf[4*4096];
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extern char *optarg;
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extern char *__progname;
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TAILQ_INIT(&pkcs11_keylist);
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pkcs11_init(0);
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init_rng();
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seed_rng();
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__progname = ssh_get_progname(argv[0]);
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log_init(__progname, log_level, log_facility, log_stderr);
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in = STDIN_FILENO;
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out = STDOUT_FILENO;
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max = 0;
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if (in > max)
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max = in;
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if (out > max)
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max = out;
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buffer_init(&iqueue);
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buffer_init(&oqueue);
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set_size = howmany(max + 1, NFDBITS) * sizeof(fd_mask);
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rset = (fd_set *)xmalloc(set_size);
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wset = (fd_set *)xmalloc(set_size);
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for (;;) {
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memset(rset, 0, set_size);
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memset(wset, 0, set_size);
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/*
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* Ensure that we can read a full buffer and handle
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* the worst-case length packet it can generate,
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* otherwise apply backpressure by stopping reads.
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*/
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if (buffer_check_alloc(&iqueue, sizeof(buf)) &&
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buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
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FD_SET(in, rset);
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olen = buffer_len(&oqueue);
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if (olen > 0)
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FD_SET(out, wset);
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if (select(max+1, rset, wset, NULL, NULL) < 0) {
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if (errno == EINTR)
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continue;
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error("select: %s", strerror(errno));
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cleanup_exit(2);
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}
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/* copy stdin to iqueue */
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if (FD_ISSET(in, rset)) {
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len = read(in, buf, sizeof buf);
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if (len == 0) {
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debug("read eof");
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cleanup_exit(0);
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} else if (len < 0) {
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error("read: %s", strerror(errno));
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cleanup_exit(1);
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} else {
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buffer_append(&iqueue, buf, len);
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}
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}
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/* send oqueue to stdout */
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if (FD_ISSET(out, wset)) {
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len = write(out, buffer_ptr(&oqueue), olen);
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if (len < 0) {
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error("write: %s", strerror(errno));
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cleanup_exit(1);
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} else {
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buffer_consume(&oqueue, len);
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}
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}
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/*
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* Process requests from client if we can fit the results
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* into the output buffer, otherwise stop processing input
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* and let the output queue drain.
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*/
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if (buffer_check_alloc(&oqueue, MAX_MSG_LENGTH))
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process();
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}
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}
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#else /* ENABLE_PKCS11 */
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int
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main(int argc, char **argv)
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{
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extern char *__progname;
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__progname = ssh_get_progname(argv[0]);
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log_init(__progname, SYSLOG_LEVEL_ERROR, SYSLOG_FACILITY_AUTH, 0);
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fatal("PKCS#11 support disabled at compile time");
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}
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#endif /* ENABLE_PKCS11 */
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