/* Copyright 2003 Roger Dingledine.
* Copyright 2004-2007 Roger Dingledine, Nick Mathewson */
/* See LICENSE for licensing information */
/* $Id$ */
const char tortls_c_id[] =
"$Id$";
/**
* \file tortls.c
* \brief Wrapper functions to present a consistent interface to
* TLS, SSL, and X.509 functions from OpenSSL.
**/
/* (Unlike other tor functions, these
* are prefixed with tor_ in order to avoid conflicting with OpenSSL
* functions and variables.)
*/
#include "orconfig.h"
#include <assert.h>
#include <openssl/ssl.h>
#include <openssl/ssl3.h>
#include <openssl/err.h>
#include <openssl/tls1.h>
#include <openssl/asn1.h>
#include <openssl/bio.h>
#define CRYPTO_PRIVATE /* to import prototypes from crypto.h */
#include "./crypto.h"
#include "./tortls.h"
#include "./util.h"
#include "./log.h"
#include <string.h>
// #define V2_HANDSHAKE_SERVER
/* Copied from or.h */
#define LEGAL_NICKNAME_CHARACTERS \
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
/** How long do identity certificates live? (sec) */
#define IDENTITY_CERT_LIFETIME (365*24*60*60)
/** Structure holding the TLS state for a single connection. */
typedef struct tor_tls_context_t {
int refcnt;
SSL_CTX *ctx;
X509 *my_cert;
X509 *my_id_cert;
crypto_pk_env_t *key;
} tor_tls_context_t;
/** Holds a SSL object and its associated data. Members are only
* accessed from within tortls.c.
*/
struct tor_tls_t {
tor_tls_context_t *context; /**DOCDOC */
SSL *ssl; /**< An OpenSSL SSL object. */
int socket; /**< The underlying file descriptor for this TLS connection. */
enum {
TOR_TLS_ST_HANDSHAKE, TOR_TLS_ST_OPEN, TOR_TLS_ST_GOTCLOSE,
TOR_TLS_ST_SENTCLOSE, TOR_TLS_ST_CLOSED, TOR_TLS_ST_RENEGOTIATE,
} state : 6; /**< The current SSL state, depending on which operations have
* completed successfully. */
unsigned int isServer:1; /**< True iff this is a server-side connection */
unsigned int hadCert:1; /**< Docdoc */
size_t wantwrite_n; /**< 0 normally, >0 if we returned wantwrite last
* time. */
unsigned long last_write_count;
unsigned long last_read_count;
};
static void tor_tls_context_decref(tor_tls_context_t *ctx);
static void tor_tls_context_incref(tor_tls_context_t *ctx);
static X509* tor_tls_create_certificate(crypto_pk_env_t *rsa,
crypto_pk_env_t *rsa_sign,
const char *cname,
const char *cname_sign,
unsigned int lifetime);
/** Global tls context. We keep it here because nobody else needs to
* touch it. */
static tor_tls_context_t *global_tls_context = NULL;
/** True iff tor_tls_init() has been called. */
static int tls_library_is_initialized = 0;
/* Module-internal error codes. */
#define _TOR_TLS_SYSCALL (_MIN_TOR_TLS_ERROR_VAL - 2)
#define _TOR_TLS_ZERORETURN (_MIN_TOR_TLS_ERROR_VAL - 1)
/** Log all pending tls errors at level <b>severity</b>. Use
* <b>doing</b> to describe our current activities.
*/
static void
tls_log_errors(int severity, const char *doing)
{
int err;
const char *msg, *lib, *func;
while ((err = ERR_get_error()) != 0) {
msg = (const char*)ERR_reason_error_string(err);
lib = (const char*)ERR_lib_error_string(err);
func = (const char*)ERR_func_error_string(err);
if (!msg) msg = "(null)";
if (doing) {
log(severity, LD_NET, "TLS error while %s: %s (in %s:%s)",
doing, msg, lib,func);
} else {
log(severity, LD_NET, "TLS error: %s (in %s:%s)", msg, lib, func);
}
}
}
/** Convert an errno (or a WSAerrno on windows) into a TOR_TLS_* error
* code. */
static int
tor_errno_to_tls_error(int e)
{
#if defined(MS_WINDOWS) && !defined(USE_BSOCKETS)
switch (e) {
case WSAECONNRESET: // most common
return TOR_TLS_ERROR_CONNRESET;
case WSAETIMEDOUT:
return TOR_TLS_ERROR_TIMEOUT;
case WSAENETUNREACH:
case WSAEHOSTUNREACH:
return TOR_TLS_ERROR_NO_ROUTE;
case WSAECONNREFUSED:
return TOR_TLS_ERROR_CONNREFUSED; // least common
default:
return TOR_TLS_ERROR_MISC;
}
#else
switch (e) {
case ECONNRESET: // most common
return TOR_TLS_ERROR_CONNRESET;
case ETIMEDOUT:
return TOR_TLS_ERROR_TIMEOUT;
case EHOSTUNREACH:
case ENETUNREACH:
return TOR_TLS_ERROR_NO_ROUTE;
case ECONNREFUSED:
return TOR_TLS_ERROR_CONNREFUSED; // least common
default:
return TOR_TLS_ERROR_MISC;
}
#endif
}
/** DOCDOC */
const char *
tor_tls_err_to_string(int err)
{
if (err >= 0)
return "[Not an error.]";
switch (err) {
case TOR_TLS_ERROR_MISC: return "misc error";
case TOR_TLS_ERROR_IO: return "unexpected close";
case TOR_TLS_ERROR_CONNREFUSED: return "connection refused";
case TOR_TLS_ERROR_CONNRESET: return "connection reset";
case TOR_TLS_ERROR_NO_ROUTE: return "host unreachable";
case TOR_TLS_ERROR_TIMEOUT: return "connection timed out";
case TOR_TLS_CLOSE: return "closed";
case TOR_TLS_WANTREAD: return "want to read";
case TOR_TLS_WANTWRITE: return "want to write";
default: return "(unknown error code)";
}
}
#define CATCH_SYSCALL 1
#define CATCH_ZERO 2
/** Given a TLS object and the result of an SSL_* call, use
* SSL_get_error to determine whether an error has occurred, and if so
* which one. Return one of TOR_TLS_{DONE|WANTREAD|WANTWRITE|ERROR}.
* If extra&CATCH_SYSCALL is true, return _TOR_TLS_SYSCALL instead of
* reporting syscall errors. If extra&CATCH_ZERO is true, return
* _TOR_TLS_ZERORETURN instead of reporting zero-return errors.
*
* If an error has occurred, log it at level <b>severity</b> and describe the
* current action as <b>doing</b>.
*/
static int
tor_tls_get_error(tor_tls_t *tls, int r, int extra,
const char *doing, int severity)
{
int err = SSL_get_error(tls->ssl, r);
int tor_error = TOR_TLS_ERROR_MISC;
switch (err) {
case SSL_ERROR_NONE:
return TOR_TLS_DONE;
case SSL_ERROR_WANT_READ:
return TOR_TLS_WANTREAD;
case SSL_ERROR_WANT_WRITE:
return TOR_TLS_WANTWRITE;
case SSL_ERROR_SYSCALL:
if (extra&CATCH_SYSCALL)
return _TOR_TLS_SYSCALL;
if (r == 0) {
log(severity, LD_NET, "TLS error: unexpected close while %s", doing);
tor_error = TOR_TLS_ERROR_IO;
} else {
int e = tor_socket_errno(tls->socket);
log(severity, LD_NET,
"TLS error: <syscall error while %s> (errno=%d: %s)",
doing, e, tor_socket_strerror(e));
tor_error = tor_errno_to_tls_error(e);
}
tls_log_errors(severity, doing);
return tor_error;
case SSL_ERROR_ZERO_RETURN:
if (extra&CATCH_ZERO)
return _TOR_TLS_ZERORETURN;
log(severity, LD_NET, "TLS error: Zero return");
tls_log_errors(severity, doing);
/* XXXX020 Actually, a 'zero return' error has a pretty specific meaning:
* the connection has been closed cleanly. */
return TOR_TLS_ERROR_MISC;
default:
tls_log_errors(severity, doing);
return TOR_TLS_ERROR_MISC;
}
}
/** Initialize OpenSSL, unless it has already been initialized.
*/
static void
tor_tls_init(void)
{
if (!tls_library_is_initialized) {
SSL_library_init();
SSL_load_error_strings();
crypto_global_init(-1);
tls_library_is_initialized = 1;
}
}
/** Free all global TLS structures. */
void
tor_tls_free_all(void)
{
if (global_tls_context) {
tor_tls_context_decref(global_tls_context);
global_tls_context = NULL;
}
}
/** We need to give OpenSSL a callback to verify certificates. This is
* it: We always accept peer certs and complete the handshake. We
* don't validate them until later.
*/
static int
always_accept_verify_cb(int preverify_ok,
X509_STORE_CTX *x509_ctx)
{
/* avoid "unused parameter" warning. */
preverify_ok = 0;
x509_ctx = NULL;
return 1;
}
/** Generate and sign an X509 certificate with the public key <b>rsa</b>,
* signed by the private key <b>rsa_sign</b>. The commonName of the
* certificate will be <b>cname</b>; the commonName of the issuer will be
* <b>cname_sign</b>. The cert will be valid for <b>cert_lifetime</b> seconds
* starting from now. Return a certificate on success, NULL on
* failure.
*/
static X509 *
tor_tls_create_certificate(crypto_pk_env_t *rsa,
crypto_pk_env_t *rsa_sign,
const char *cname,
const char *cname_sign,
unsigned int cert_lifetime)
{
time_t start_time, end_time;
EVP_PKEY *sign_pkey = NULL, *pkey=NULL;
X509 *x509 = NULL;
X509_NAME *name = NULL, *name_issuer=NULL;
int nid;
tor_tls_init();
start_time = time(NULL);
tor_assert(rsa);
tor_assert(cname);
tor_assert(rsa_sign);
tor_assert(cname_sign);
if (!(sign_pkey = _crypto_pk_env_get_evp_pkey(rsa_sign,1)))
goto error;
if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,0)))
goto error;
if (!(x509 = X509_new()))
goto error;
if (!(X509_set_version(x509, 2)))
goto error;
if (!(ASN1_INTEGER_set(X509_get_serialNumber(x509), (long)start_time)))
goto error;
if (!(name = X509_NAME_new()))
goto error;
if ((nid = OBJ_txt2nid("organizationName")) == NID_undef)
goto error;
if (!(X509_NAME_add_entry_by_NID(name, nid, MBSTRING_ASC,
(unsigned char*)"t o r", -1, -1, 0)))
goto error;
if ((nid = OBJ_txt2nid("commonName")) == NID_undef) goto error;
if (!(X509_NAME_add_entry_by_NID(name, nid, MBSTRING_ASC,
(unsigned char*)cname, -1, -1, 0)))
goto error;
if (!(X509_set_subject_name(x509, name)))
goto error;
if (!(name_issuer = X509_NAME_new()))
goto error;
if ((nid = OBJ_txt2nid("organizationName")) == NID_undef)
goto error;
if (!(X509_NAME_add_entry_by_NID(name_issuer, nid, MBSTRING_ASC,
(unsigned char*)"t o r", -1, -1, 0)))
goto error;
if ((nid = OBJ_txt2nid("commonName")) == NID_undef) goto error;
if (!(X509_NAME_add_entry_by_NID(name_issuer, nid, MBSTRING_ASC,
(unsigned char*)cname_sign, -1, -1, 0)))
goto error;
if (!(X509_set_issuer_name(x509, name_issuer)))
goto error;
if (!X509_time_adj(X509_get_notBefore(x509),0,&start_time))
goto error;
end_time = start_time + cert_lifetime;
if (!X509_time_adj(X509_get_notAfter(x509),0,&end_time))
goto error;
if (!X509_set_pubkey(x509, pkey))
goto error;
if (!X509_sign(x509, sign_pkey, EVP_sha1()))
goto error;
goto done;
error:
if (x509) {
X509_free(x509);
x509 = NULL;
}
done:
tls_log_errors(LOG_WARN, "generating certificate");
if (sign_pkey)
EVP_PKEY_free(sign_pkey);
if (pkey)
EVP_PKEY_free(pkey);
if (name)
X509_NAME_free(name);
if (name_issuer)
X509_NAME_free(name_issuer);
return x509;
}
#ifdef EVERYONE_HAS_AES
/* Everybody is running OpenSSL 0.9.7 or later, so no backward compatibility
* is needed. */
#define CIPHER_LIST TLS1_TXT_DHE_RSA_WITH_AES_128_SHA
#elif defined(TLS1_TXT_DHE_RSA_WITH_AES_128_SHA)
/* Some people are running OpenSSL before 0.9.7, but we aren't.
* We can support AES and 3DES.
*/
#define CIPHER_LIST (TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \
SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA)
/* Note: for setting up your own private testing network with link
* crypto disabled, set your cipher list to SSL3_TXT_RSA_NULL_SHA.
* If you do this, you won't be able to communicate with any of the
* "real" Tors, though. */
#else
#error "Tor requires OpenSSL version 0.9.7 or later, for AES support."
#endif
/** DOCDOC */
static void
tor_tls_context_decref(tor_tls_context_t *ctx)
{
tor_assert(ctx);
if (--ctx->refcnt == 0) {
SSL_CTX_free(ctx->ctx);
X509_free(ctx->my_cert);
X509_free(ctx->my_id_cert);
crypto_free_pk_env(ctx->key);
tor_free(ctx);
}
}
/** DOCDOC */
static void
tor_tls_context_incref(tor_tls_context_t *ctx)
{
++ctx->refcnt;
}
/** Create a new TLS context for use with Tor TLS handshakes.
* <b>identity</b> should be set to the identity key used to sign the
* certificate, and <b>nickname</b> set to the nickname to use.
*
* You can call this function multiple times. Each time you call it,
* it generates new certificates; all new connections will use
* the new SSL context.
*/
int
tor_tls_context_new(crypto_pk_env_t *identity, const char *nickname,
unsigned int key_lifetime)
{
crypto_pk_env_t *rsa = NULL;
crypto_dh_env_t *dh = NULL;
EVP_PKEY *pkey = NULL;
tor_tls_context_t *result = NULL;
X509 *cert = NULL, *idcert = NULL;
char nn2[128];
if (!nickname)
nickname = "null";
tor_snprintf(nn2, sizeof(nn2), "%s <signing>", nickname);
tor_tls_init();
/* Generate short-term RSA key. */
if (!(rsa = crypto_new_pk_env()))
goto error;
if (crypto_pk_generate_key(rsa)<0)
goto error;
/* Create certificate signed by identity key. */
cert = tor_tls_create_certificate(rsa, identity, nickname, nn2,
key_lifetime);
/* Create self-signed certificate for identity key. */
idcert = tor_tls_create_certificate(identity, identity, nn2, nn2,
IDENTITY_CERT_LIFETIME);
if (!cert || !idcert) {
log(LOG_WARN, LD_CRYPTO, "Error creating certificate");
goto error;
}
result = tor_malloc_zero(sizeof(tor_tls_context_t));
result->refcnt = 1;
result->my_cert = X509_dup(cert);
result->my_id_cert = X509_dup(idcert);
result->key = crypto_pk_dup_key(rsa);
#ifdef EVERYONE_HAS_AES
/* Tell OpenSSL to only use TLS1 */
if (!(result->ctx = SSL_CTX_new(TLSv1_method())))
goto error;
#else
/* Tell OpenSSL to use SSL3 or TLS1 but not SSL2. */
if (!(result->ctx = SSL_CTX_new(SSLv23_method())))
goto error;
SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv2);
#endif
SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_DH_USE);
if (!SSL_CTX_set_cipher_list(result->ctx, CIPHER_LIST))
goto error;
if (cert && !SSL_CTX_use_certificate(result->ctx,cert))
goto error;
X509_free(cert); /* We just added a reference to cert. */
cert=NULL;
#if 0
if (idcert && !SSL_CTX_add_extra_chain_cert(result->ctx,idcert))
goto error;
#else
if (idcert) {
X509_STORE *s = SSL_CTX_get_cert_store(result->ctx);
tor_assert(s);
X509_STORE_add_cert(s, idcert);
}
#endif
idcert=NULL; /* The context now owns the reference to idcert */
SSL_CTX_set_session_cache_mode(result->ctx, SSL_SESS_CACHE_OFF);
tor_assert(rsa);
if (!(pkey = _crypto_pk_env_get_evp_pkey(rsa,1)))
goto error;
if (!SSL_CTX_use_PrivateKey(result->ctx, pkey))
goto error;
EVP_PKEY_free(pkey);
pkey = NULL;
if (!SSL_CTX_check_private_key(result->ctx))
goto error;
dh = crypto_dh_new();
SSL_CTX_set_tmp_dh(result->ctx, _crypto_dh_env_get_dh(dh));
crypto_dh_free(dh);
SSL_CTX_set_verify(result->ctx, SSL_VERIFY_PEER,
always_accept_verify_cb);
/* let us realloc bufs that we're writing from */
SSL_CTX_set_mode(result->ctx, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
/* Free the old context if one exists. */
if (global_tls_context) {
/* This is safe even if there are open connections: OpenSSL does
* reference counting with SSL and SSL_CTX objects. */
tor_tls_context_decref(global_tls_context);
}
global_tls_context = result;
if (rsa)
crypto_free_pk_env(rsa);
return 0;
error:
tls_log_errors(LOG_WARN, "creating TLS context");
if (pkey)
EVP_PKEY_free(pkey);
if (rsa)
crypto_free_pk_env(rsa);
if (dh)
crypto_dh_free(dh);
if (result)
tor_tls_context_decref(result);
if (cert)
X509_free(cert);
if (idcert)
X509_free(idcert);
return -1;
}
#ifdef V2_HANDSHAKE_SERVER
static void
tor_tls_server_info_callback(const SSL *ssl, int type, int val)
{
int all_ciphers_in_v1_list = 1;
int i;
SSL_SESSION *session;
(void) val;
if (type != SSL_CB_ACCEPT_LOOP)
return;
if (ssl->state != SSL3_ST_SW_SRVR_HELLO_A)
return;
/* If we reached this point, we just got a client hello. See if there is
* a cipher list. */
if (!(session = SSL_get_session(ssl))) {
log_warn(LD_NET, "No session on TLS?");
return;
}
if (!session->ciphers) {
log_warn(LD_NET, "No ciphers on session");
return;
}
/* Now we need to see if there are any ciphers whose presence means we're
* dealing with an updated Tor. */
for (i = 0; i < sk_SSL_CIPHER_num(session->ciphers); ++i) {
SSL_CIPHER *cipher = sk_SSL_CIPHER_value(session->ciphers, i);
const char *ciphername = SSL_CIPHER_get_name(cipher);
if (strcmp(ciphername, TLS1_TXT_DHE_RSA_WITH_AES_128_SHA) &&
strcmp(ciphername, SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA) &&
strcmp(ciphername, "(NONE)")) {
/* XXXX should be ld_debug */
log_info(LD_NET, "Got a non-version-1 cipher called '%s'",ciphername);
all_ciphers_in_v1_list = 0;
break;
}
}
if (!all_ciphers_in_v1_list) {
/* Yes, we're casting away the const from ssl. This is very naughty of us.
* Let's hope openssl doesn't notice! */
/* Set SSL_MODE_NO_AUTO_CHAIN to keep from sending back any extra certs. */
SSL_set_mode((SSL*) ssl, SSL_MODE_NO_AUTO_CHAIN);
/* Don't send a hello request. */
SSL_set_verify((SSL*) ssl, SSL_VERIFY_NONE, NULL);
}
}
#endif
/** Create a new TLS object from a file descriptor, and a flag to
* determine whether it is functioning as a server.
*/
tor_tls_t *
tor_tls_new(int sock, int isServer)
{
BIO *bio = NULL;
tor_tls_t *result = tor_malloc_zero(sizeof(tor_tls_t));
tor_assert(global_tls_context); /* make sure somebody made it first */
if (!(result->ssl = SSL_new(global_tls_context->ctx))) {
tls_log_errors(LOG_WARN, "generating TLS context");
tor_free(result);
return NULL;
}
result->socket = sock;
#ifdef USE_BSOCKETS
bio = BIO_new_bsocket(sock, BIO_NOCLOSE);
#else
bio = BIO_new_socket(sock, BIO_NOCLOSE);
#endif
if (! bio) {
tls_log_errors(LOG_WARN, "opening BIO");
SSL_free(result->ssl);
tor_free(result);
return NULL;
}
SSL_set_bio(result->ssl, bio, bio);
tor_tls_context_incref(global_tls_context);
result->context = global_tls_context;
result->state = TOR_TLS_ST_HANDSHAKE;
result->isServer = isServer;
result->wantwrite_n = 0;
#ifdef V2_HANDSHAKE_SERVER
if (isServer) {
SSL_set_info_callback(result->ssl, tor_tls_server_info_callback);
}
#endif
/* Not expected to get called. */
tls_log_errors(LOG_WARN, "generating TLS context");
return result;
}
/** Return whether this tls initiated the connect (client) or
* received it (server). */
int
tor_tls_is_server(tor_tls_t *tls)
{
tor_assert(tls);
return tls->isServer;
}
/** Release resources associated with a TLS object. Does not close the
* underlying file descriptor.
*/
void
tor_tls_free(tor_tls_t *tls)
{
tor_assert(tls && tls->ssl);
SSL_free(tls->ssl);
tls->ssl = NULL;
if (tls->context)
tor_tls_context_decref(tls->context);
tor_free(tls);
}
/** Underlying function for TLS reading. Reads up to <b>len</b>
* characters from <b>tls</b> into <b>cp</b>. On success, returns the
* number of characters read. On failure, returns TOR_TLS_ERROR,
* TOR_TLS_CLOSE, TOR_TLS_WANTREAD, or TOR_TLS_WANTWRITE.
*/
int
tor_tls_read(tor_tls_t *tls, char *cp, size_t len)
{
int r, err;
tor_assert(tls);
tor_assert(tls->ssl);
tor_assert(tls->state == TOR_TLS_ST_OPEN);
r = SSL_read(tls->ssl, cp, len);
if (r > 0) {
#ifdef V2_HANDSHAKE_SERVER
if (!tls->hadCert && tls->ssl->session && tls->ssl->session->peer) {
tls->hadCert = 1;
/* New certificate! */
log_info(LD_NET, "Got a TLS renegotiation.");
/* XXXX020 call some kind of 'there was a renegotiation' callback. */
}
#endif
return r;
}
err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading", LOG_DEBUG);
if (err == _TOR_TLS_ZERORETURN) {
log_debug(LD_NET,"read returned r=%d; TLS is closed",r);
tls->state = TOR_TLS_ST_CLOSED;
return TOR_TLS_CLOSE;
} else {
tor_assert(err != TOR_TLS_DONE);
log_debug(LD_NET,"read returned r=%d, err=%d",r,err);
return err;
}
}
/** Underlying function for TLS writing. Write up to <b>n</b>
* characters from <b>cp</b> onto <b>tls</b>. On success, returns the
* number of characters written. On failure, returns TOR_TLS_ERROR,
* TOR_TLS_WANTREAD, or TOR_TLS_WANTWRITE.
*/
int
tor_tls_write(tor_tls_t *tls, const char *cp, size_t n)
{
int r, err;
tor_assert(tls);
tor_assert(tls->ssl);
tor_assert(tls->state == TOR_TLS_ST_OPEN);
if (n == 0)
return 0;
if (tls->wantwrite_n) {
/* if WANTWRITE last time, we must use the _same_ n as before */
tor_assert(n >= tls->wantwrite_n);
log_debug(LD_NET,"resuming pending-write, (%d to flush, reusing %d)",
(int)n, (int)tls->wantwrite_n);
n = tls->wantwrite_n;
tls->wantwrite_n = 0;
}
r = SSL_write(tls->ssl, cp, n);
err = tor_tls_get_error(tls, r, 0, "writing", LOG_INFO);
if (err == TOR_TLS_DONE) {
return r;
}
if (err == TOR_TLS_WANTWRITE || err == TOR_TLS_WANTREAD) {
tls->wantwrite_n = n;
}
return err;
}
/** Perform initial handshake on <b>tls</b>. When finished, returns
* TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD,
* or TOR_TLS_WANTWRITE.
*/
int
tor_tls_handshake(tor_tls_t *tls)
{
int r;
tor_assert(tls);
tor_assert(tls->ssl);
tor_assert(tls->state == TOR_TLS_ST_HANDSHAKE);
check_no_tls_errors();
if (tls->isServer) {
r = SSL_accept(tls->ssl);
} else {
r = SSL_connect(tls->ssl);
}
r = tor_tls_get_error(tls,r,0, "handshaking", LOG_INFO);
if (ERR_peek_error() != 0) {
tls_log_errors(tls->isServer ? LOG_INFO : LOG_WARN,
"handshaking");
return TOR_TLS_ERROR_MISC;
}
if (r == TOR_TLS_DONE) {
tls->state = TOR_TLS_ST_OPEN;
tls->hadCert = tor_tls_peer_has_cert(tls) ? 1 : 0;
if (tls->isServer) {
SSL_set_info_callback(tls->ssl, NULL);
SSL_set_verify(tls->ssl, SSL_VERIFY_NONE, always_accept_verify_cb);
tls->ssl->mode &= ~SSL_MODE_NO_AUTO_CHAIN;
}
}
return r;
}
/** Client only: Renegotiate a TLS session. When finished, returns
* TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD, or
* TOR_TLS_WANTWRITE.
*/
int
tor_tls_renegotiate(tor_tls_t *tls)
{
int r;
tor_assert(tls);
/* We could do server-initiated renegotiation too, but that would be tricky.
* Instead of "SSL_renegotiate, then SSL_do_handshake until done" */
tor_assert(!tls->isServer);
if (tls->state != TOR_TLS_ST_RENEGOTIATE) {
int r = SSL_renegotiate(tls->ssl);
if (r <= 0) {
return tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO,
"renegotiating", LOG_WARN);
}
tls->state = TOR_TLS_ST_RENEGOTIATE;
}
r = SSL_do_handshake(tls->ssl);
if (r == 1) {
tls->state = TOR_TLS_ST_OPEN;
return TOR_TLS_DONE;
} else
return tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO,
"renegotiating handshake", LOG_WARN);
}
/** Shut down an open tls connection <b>tls</b>. When finished, returns
* TOR_TLS_DONE. On failure, returns TOR_TLS_ERROR, TOR_TLS_WANTREAD,
* or TOR_TLS_WANTWRITE.
*/
int
tor_tls_shutdown(tor_tls_t *tls)
{
int r, err;
char buf[128];
tor_assert(tls);
tor_assert(tls->ssl);
while (1) {
if (tls->state == TOR_TLS_ST_SENTCLOSE) {
/* If we've already called shutdown once to send a close message,
* we read until the other side has closed too.
*/
do {
r = SSL_read(tls->ssl, buf, 128);
} while (r>0);
err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading to shut down",
LOG_INFO);
if (err == _TOR_TLS_ZERORETURN) {
tls->state = TOR_TLS_ST_GOTCLOSE;
/* fall through... */
} else {
return err;
}
}
r = SSL_shutdown(tls->ssl);
if (r == 1) {
/* If shutdown returns 1, the connection is entirely closed. */
tls->state = TOR_TLS_ST_CLOSED;
return TOR_TLS_DONE;
}
err = tor_tls_get_error(tls, r, CATCH_SYSCALL|CATCH_ZERO, "shutting down",
LOG_INFO);
if (err == _TOR_TLS_SYSCALL) {
/* The underlying TCP connection closed while we were shutting down. */
tls->state = TOR_TLS_ST_CLOSED;
return TOR_TLS_DONE;
} else if (err == _TOR_TLS_ZERORETURN) {
/* The TLS connection says that it sent a shutdown record, but
* isn't done shutting down yet. Make sure that this hasn't
* happened before, then go back to the start of the function
* and try to read.
*/
if (tls->state == TOR_TLS_ST_GOTCLOSE ||
tls->state == TOR_TLS_ST_SENTCLOSE) {
log(LOG_WARN, LD_NET,
"TLS returned \"half-closed\" value while already half-closed");
return TOR_TLS_ERROR_MISC;
}
tls->state = TOR_TLS_ST_SENTCLOSE;
/* fall through ... */
} else {
return err;
}
} /* end loop */
}
/** Return true iff this TLS connection is authenticated.
*/
int
tor_tls_peer_has_cert(tor_tls_t *tls)
{
X509 *cert;
cert = SSL_get_peer_certificate(tls->ssl);
tls_log_errors(LOG_WARN, "getting peer certificate");
if (!cert)
return 0;
X509_free(cert);
return 1;
}
/** DOCDOC */
int
tor_tls_get_cert_digests(tor_tls_t *tls,
char *my_digest_out,
char *peer_digest_out)
{
X509 *cert;
unsigned int len;
tor_assert(tls && tls->context);
cert = tls->context->my_cert;
if (cert) {
X509_digest(cert, EVP_sha1(), (unsigned char*)my_digest_out, &len);
if (len != DIGEST_LEN)
return -1;
}
cert = SSL_get_peer_certificate(tls->ssl);
if (cert) {
X509_digest(cert, EVP_sha1(), (unsigned char*)peer_digest_out, &len);
if (len != DIGEST_LEN)
return -1;
}
return 0;
}
/** DOCDOC */
crypto_pk_env_t *
tor_tls_dup_private_key(tor_tls_t *tls)
{
return crypto_pk_dup_key(tls->context->key);
}
/** DOCDOC */
char *
tor_tls_encode_my_certificate(tor_tls_t *tls, size_t *size_out,
int conn_cert)
{
unsigned char *result, *cp;
int certlen;
X509 *cert;
tor_assert(tls && tls->context);
cert = conn_cert ? tls->context->my_cert : tls->context->my_id_cert;
tor_assert(cert);
certlen = i2d_X509(cert, NULL);
tor_assert(certlen >= 0);
cp = result = tor_malloc(certlen);
i2d_X509(cert, &cp);
tor_assert(cp-result == certlen);
*size_out = (size_t)certlen;
return (char*) result;
}
/** Warn that a certificate lifetime extends through a certain range. */
static void
log_cert_lifetime(X509 *cert, const char *problem)
{
BIO *bio = NULL;
BUF_MEM *buf;
char *s1=NULL, *s2=NULL;
char mytime[33];
time_t now = time(NULL);
struct tm tm;
if (problem)
log_warn(LD_GENERAL,
"Certificate %s: is your system clock set incorrectly?",
problem);
if (!(bio = BIO_new(BIO_s_mem()))) {
log_warn(LD_GENERAL, "Couldn't allocate BIO!"); goto end;
}
if (!(ASN1_TIME_print(bio, X509_get_notBefore(cert)))) {
tls_log_errors(LOG_WARN, "printing certificate lifetime");
goto end;
}
BIO_get_mem_ptr(bio, &buf);
s1 = tor_strndup(buf->data, buf->length);
(void)BIO_reset(bio);
if (!(ASN1_TIME_print(bio, X509_get_notAfter(cert)))) {
tls_log_errors(LOG_WARN, "printing certificate lifetime");
goto end;
}
BIO_get_mem_ptr(bio, &buf);
s2 = tor_strndup(buf->data, buf->length);
strftime(mytime, 32, "%b %d %H:%M:%S %Y GMT", tor_gmtime_r(&now, &tm));
log_warn(LD_GENERAL,
"(certificate lifetime runs from %s through %s. Your time is %s.)",
s1,s2,mytime);
end:
/* Not expected to get invoked */
tls_log_errors(LOG_WARN, "getting certificate lifetime");
if (bio)
BIO_free(bio);
if (s1)
tor_free(s1);
if (s2)
tor_free(s2);
}
/** DOCDOC helper.
* cert_out needs to be freed. id_cert_out doesn't. */
static void
try_to_extract_certs_from_tls(int severity, tor_tls_t *tls,
X509 **cert_out, X509 **id_cert_out)
{
X509 *cert = NULL, *id_cert = NULL;
STACK_OF(X509) *chain = NULL;
int num_in_chain, i;
*cert_out = *id_cert_out = NULL;
if (!(cert = SSL_get_peer_certificate(tls->ssl)))
return;
*cert_out = cert;
if (!(chain = SSL_get_peer_cert_chain(tls->ssl)))
return;
num_in_chain = sk_X509_num(chain);
/* 1 means we're receiving (server-side), and it's just the id_cert.
* 2 means we're connecting (client-side), and it's both the link
* cert and the id_cert.
*/
if (num_in_chain < 1) {
log_fn(severity,LD_PROTOCOL,
"Unexpected number of certificates in chain (%d)",
num_in_chain);
return;
}
for (i=0; i<num_in_chain; ++i) {
id_cert = sk_X509_value(chain, i);
if (X509_cmp(id_cert, cert) != 0)
break;
}
*id_cert_out = id_cert;
}
/** If the provided tls connection is authenticated and has a
* certificate that is currently valid and signed, then set
* *<b>identity_key</b> to the identity certificate's key and return
* 0. Else, return -1 and log complaints with log-level <b>severity</b>.
*/
int
tor_tls_verify_v1(int severity, tor_tls_t *tls, crypto_pk_env_t **identity_key)
{
X509 *cert = NULL, *id_cert = NULL;
EVP_PKEY *id_pkey = NULL;
RSA *rsa;
int r = -1;
*identity_key = NULL;
try_to_extract_certs_from_tls(severity, tls, &cert, &id_cert);
if (!cert)
goto done;
if (!id_cert) {
log_fn(severity,LD_PROTOCOL,"No distinct identity certificate found");
goto done;
}
if (!(id_pkey = X509_get_pubkey(id_cert)) ||
X509_verify(cert, id_pkey) <= 0) {
log_fn(severity,LD_PROTOCOL,"X509_verify on cert and pkey returned <= 0");
tls_log_errors(severity,"verifying certificate");
goto done;
}
rsa = EVP_PKEY_get1_RSA(id_pkey);
if (!rsa)
goto done;
*identity_key = _crypto_new_pk_env_rsa(rsa);
r = 0;
done:
if (cert)
X509_free(cert);
if (id_pkey)
EVP_PKEY_free(id_pkey);
/* This should never get invoked, but let's make sure in case OpenSSL
* acts unexpectedly. */
tls_log_errors(LOG_WARN, "finishing tor_tls_verify");
return r;
}
#if 0
/** DOCDOC
*
* Returns 1 on "verification is done", 0 on "still need LINK_AUTH."
*/
int
tor_tls_verify_certs_v2(int severity, tor_tls_t *tls,
const char *cert_str, size_t cert_len,
const char *id_cert_str, size_t id_cert_len,
crypto_pk_env_t **cert_key_out,
char *conn_cert_digest_out,
crypto_pk_env_t **id_key_out,
char *id_digest_out)
{
X509 *cert = NULL, *id_cert = NULL;
EVP_PKEY *id_pkey = NULL, *cert_pkey = NULL;
int free_id_cert = 0, peer_used_tls_cert = 0;
int r = -1;
tor_assert(cert_key_out);
tor_assert(conn_cert_digest_out);
tor_assert(id_key_out);
tor_assert(id_digest_out);
*cert_key_out = NULL;
if (cert_str && cert_len) {
/*XXXX020 warn on error. */
const unsigned char *cp = (const unsigned char*) cert_str;
cert = d2i_X509(NULL, &cp, cert_len);
}
if (id_cert_str && id_cert_len) {
/*XXXX020 warn on error. */
const unsigned char *cp = (const unsigned char*) id_cert_str;
id_cert = d2i_X509(NULL, &cp, id_cert_len);
if (id_cert)
free_id_cert = 1;
}
if (cert) {
int cmp = 0;
X509 *cert_tmp = SSL_get_peer_certificate(tls->ssl);
if (cert_tmp) {
peer_used_tls_cert = 1;
cmp = X509_cmp(cert, cert_tmp);
X509_free(cert_tmp);
}
if (cmp != 0) {
log_fn(severity, LD_PROTOCOL,
"Certificate in CERT cell didn't match TLS cert.");
goto done;
}
}
if (!cert || !id_cert) {
X509 *c=NULL, *id=NULL;
try_to_extract_certs_from_tls(severity, tls, &c, &id);
if (c) {
if (!cert)
cert = c;
else
X509_free(c);
}
if (id && !id_cert)
id_cert = id;
}
if (!id_cert || !cert)
goto done;
if (!(id_pkey = X509_get_pubkey(id_cert)) ||
X509_verify(cert, id_pkey) <= 0) {
log_fn(severity,LD_PROTOCOL,"X509_verify on cert and pkey returned <= 0");
tls_log_errors(severity,"verifying certificate");
goto done;
}
if (!(*id_key_out = _crypto_new_pk_env_evp_pkey(id_pkey)))
goto done;
crypto_pk_get_digest(*id_key_out, id_digest_out);
if (!(cert_pkey = X509_get_pubkey(cert)))
goto done;
if (!(*cert_key_out = _crypto_new_pk_env_evp_pkey(cert_pkey)))
goto done;
{
unsigned int len = 0;
X509_digest(cert, EVP_sha1(), (unsigned char*)conn_cert_digest_out, &len);
tor_assert(len == DIGEST_LEN);
}
r = peer_used_tls_cert ? 1 : 0;
done:
if (cert)
X509_free(cert);
if (id_cert && free_id_cert)
X509_free(id_cert);
if (id_pkey)
EVP_PKEY_free(id_pkey);
if (cert_pkey)
EVP_PKEY_free(cert_pkey);
return r;
}
#endif
/** Check whether the certificate set on the connection <b>tls</b> is
* expired or not-yet-valid, give or take <b>tolerance</b>
* seconds. Return 0 for valid, -1 for failure.
*
* NOTE: you should call tor_tls_verify before tor_tls_check_lifetime.
*/
int
tor_tls_check_lifetime(tor_tls_t *tls, int tolerance)
{
time_t now, t;
X509 *cert;
int r = -1;
now = time(NULL);
if (!(cert = SSL_get_peer_certificate(tls->ssl)))
goto done;
t = now + tolerance;
if (X509_cmp_time(X509_get_notBefore(cert), &t) > 0) {
log_cert_lifetime(cert, "not yet valid");
goto done;
}
t = now - tolerance;
if (X509_cmp_time(X509_get_notAfter(cert), &t) < 0) {
log_cert_lifetime(cert, "already expired");
goto done;
}
r = 0;
done:
if (cert)
X509_free(cert);
/* Not expected to get invoked */
tls_log_errors(LOG_WARN, "checking certificate lifetime");
return r;
}
/** Return the number of bytes available for reading from <b>tls</b>.
*/
int
tor_tls_get_pending_bytes(tor_tls_t *tls)
{
tor_assert(tls);
return SSL_pending(tls->ssl);
}
/** If <b>tls</b> requires that the next write be of a particular size,
* return that size. Otherwise, return 0. */
size_t
tor_tls_get_forced_write_size(tor_tls_t *tls)
{
return tls->wantwrite_n;
}
/** Sets n_read and n_written to the number of bytes read and written,
* respectivey, on the raw socket used by <b>tls</b> since the last time this
* function was called on <b>tls</b>. */
void
tor_tls_get_n_raw_bytes(tor_tls_t *tls, size_t *n_read, size_t *n_written)
{
unsigned long r, w;
r = BIO_number_read(SSL_get_rbio(tls->ssl));
w = BIO_number_written(SSL_get_wbio(tls->ssl));
/* We are ok with letting these unsigned ints go "negative" here:
* If we wrapped around, this should still give us the right answer, unless
* we wrapped around by more than ULONG_MAX since the last time we called
* this function.
*/
*n_read = (size_t)(r - tls->last_read_count);
*n_written = (size_t)(w - tls->last_write_count);
tls->last_read_count = r;
tls->last_write_count = w;
}
/** Implement check_no_tls_errors: If there are any pending OpenSSL
* errors, log an error message. */
void
_check_no_tls_errors(const char *fname, int line)
{
if (ERR_peek_error() == 0)
return;
log(LOG_WARN, LD_CRYPTO, "Unhandled OpenSSL errors found at %s:%d: ",
tor_fix_source_file(fname), line);
tls_log_errors(LOG_WARN, NULL);
}
/**DOCDOC */
int
tor_tls_used_v1_handshake(tor_tls_t *tls)
{
(void)tls;
return 1;
}
#if SSL3_RANDOM_SIZE != TOR_TLS_RANDOM_LEN
#error "The TOR_TLS_RANDOM_LEN macro is defined incorrectly. That's a bug."
#endif
/** DOCDOC */
int
tor_tls_get_random_values(tor_tls_t *tls, char *client_random_out,
char *server_random_out)
{
tor_assert(tls && tls->ssl);
if (!tls->ssl->s3)
return -1;
memcpy(client_random_out, tls->ssl->s3->client_random, SSL3_RANDOM_SIZE);
memcpy(server_random_out, tls->ssl->s3->server_random, SSL3_RANDOM_SIZE);
return 0;
}
/** DOCDOC */
int
tor_tls_hmac_with_master_secret(tor_tls_t *tls, char *hmac_out,
const char *data, size_t data_len)
{
SSL_SESSION *s;
tor_assert(tls && tls->ssl);
if (!(s = SSL_get_session(tls->ssl)))
return -1;
if (s->master_key_length < 0)
return -1;
crypto_hmac_sha1(hmac_out,
(const char*)s->master_key,
(size_t)s->master_key_length,
data, data_len);
return 0;
}