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/* $OpenBSD: ssh-pkcs11-helper.c,v 1.13 2017/05/30 08:52:19 markus 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 <sys/types.h> |
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#include <sys/queue.h> |
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#include <sys/time.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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struct sshkey *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(struct sshkey *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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free(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 struct sshkey * |
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lookup_key(struct sshkey *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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struct sshkey **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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if (key_to_blob(keys[i], &blob, &blen) == 0) |
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continue; |
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buffer_put_string(&msg, blob, blen); |
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buffer_put_cstring(&msg, name); |
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free(blob); |
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add_key(keys[i], name); |
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} |
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free(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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free(pin); |
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free(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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free(pin); |
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free(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; |
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struct sshkey *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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(void)get_int(); /* XXX ignore flags */ |
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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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#ifdef WITH_OPENSSL |
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int ret; |
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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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#endif /* WITH_OPENSSL */ |
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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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free(data); |
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free(blob); |
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free(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 *__progname; |
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ssh_malloc_init(); /* must be called before any mallocs */ |
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TAILQ_INIT(&pkcs11_keylist); |
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pkcs11_init(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 = xmalloc(set_size); |
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wset = 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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} |