/* Copyright (c) 2003, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2008, The Tor Project, Inc. */
/* 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>
#include <openssl/opensslv.h>
#if OPENSSL_VERSION_NUMBER < 0x00907000l
#error "We require openssl >= 0.9.7"
#endif
#define CRYPTO_PRIVATE /* to import prototypes from crypto.h */
#include "crypto.h"
#include "tortls.h"
#include "util.h"
#include "log.h"
#include "container.h"
#include "ht.h"
#include <string.h>
// #define V2_HANDSHAKE_SERVER
// #define V2_HANDSHAKE_CLIENT
/* 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 {
HT_ENTRY(tor_tls_t) node;
tor_tls_context_t *context; /** A link to the context object for this tls */
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 : 3; /**< 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 wasV2Handshake:1; /**< True iff the original handshake for
* this connection used the updated version
* of the connection protocol (client sends
* different cipher list, server sends only
* one certificate). */
int got_renegotiate:1; /**< True iff we should call negotiated_callback
* when we're done reading. */
size_t wantwrite_n; /**< 0 normally, >0 if we returned wantwrite last
* time. */
/** Last values retrieved from BIO_number_read()/write(); see
* tor_tls_get_n_raw_bytes() for usage.
*/
unsigned long last_write_count;
unsigned long last_read_count;
/** If set, a callback to invoke whenever the client tries to renegotiate
* the handshake. */
void (*negotiated_callback)(tor_tls_t *tls, void *arg);
/** Argument to pass to negotiated_callback. */
void *callback_arg;
};
/** Helper: compare tor_tls_t objects by its SSL. */
static INLINE int
tor_tls_entries_eq(const tor_tls_t *a, const tor_tls_t *b)
{
return a->ssl == b->ssl;
}
/** Helper: return a hash value for a tor_tls_t by its SSL. */
static INLINE unsigned int
tor_tls_entry_hash(const tor_tls_t *a)
{
#if SIZEOF_INT == SIZEOF_VOID_P
return ((unsigned int)a->ssl);
#else
return (unsigned int) ((((uint64_t)a->ssl)>>2) & UINT_MAX);
#endif
}
/** Map from SSL* pointers to tor_tls_t objects using those pointers.
*/
static HT_HEAD(tlsmap, tor_tls_t) tlsmap_root = HT_INITIALIZER();
HT_PROTOTYPE(tlsmap, tor_tls_t, node, tor_tls_entry_hash,
tor_tls_entries_eq)
HT_GENERATE(tlsmap, tor_tls_t, node, tor_tls_entry_hash,
tor_tls_entries_eq, 0.6, malloc, realloc, free)
/** Helper: given a SSL* pointer, return the tor_tls_t object using that
* pointer. */
static INLINE tor_tls_t *
tor_tls_get_by_ssl(const SSL *ssl)
{
tor_tls_t search, *result;
memset(&search, 0, sizeof(search));
search.ssl = (SSL*)ssl;
result = HT_FIND(tlsmap, &tlsmap_root, &search);
return result;
}
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
}
/** Given a TOR_TLS_* error code, return a string equivalent. */
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)
{
(void) preverify_ok;
(void) x509_ctx;
return 1;
}
/** Return a newly allocated X509 name with commonName <b>cname</b>. */
static X509_NAME *
tor_x509_name_new(const char *cname)
{
int nid;
X509_NAME *name;
if (!(name = X509_NAME_new()))
return NULL;
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;
return name;
error:
X509_NAME_free(name);
return NULL;
}
/** 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;
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 = tor_x509_name_new(cname)))
goto error;
if (!(X509_set_subject_name(x509, name)))
goto error;
if (!(name_issuer = tor_x509_name_new(cname_sign)))
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;
}
#define SERVER_CIPHER_LIST \
(TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \
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 the cipher lists to 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. */
#if OPENSSL_VERSION_NUMBER >= 0x00908000l
#define CLIENT_CIPHER_LIST \
(TLS1_TXT_ECDHE_ECDSA_WITH_AES_256_CBC_SHA ":" \
TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":" \
TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \
TLS1_TXT_DHE_DSS_WITH_AES_256_SHA ":" \
TLS1_TXT_ECDH_RSA_WITH_AES_256_CBC_SHA ":" \
TLS1_TXT_ECDH_ECDSA_WITH_AES_256_CBC_SHA ":" \
TLS1_TXT_RSA_WITH_AES_256_SHA ":" \
TLS1_TXT_ECDHE_ECDSA_WITH_RC4_128_SHA ":" \
TLS1_TXT_ECDHE_ECDSA_WITH_AES_128_CBC_SHA ":" \
TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA ":" \
TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA ":" \
TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \
TLS1_TXT_DHE_DSS_WITH_AES_128_SHA ":" \
TLS1_TXT_ECDH_RSA_WITH_RC4_128_SHA":" \
TLS1_TXT_ECDH_RSA_WITH_AES_128_CBC_SHA":" \
TLS1_TXT_ECDH_ECDSA_WITH_RC4_128_SHA ":" \
TLS1_TXT_ECDH_ECDSA_WITH_AES_128_CBC_SHA ":" \
SSL3_TXT_RSA_RC4_128_MD5 ":" \
SSL3_TXT_RSA_RC4_128_SHA ":" \
TLS1_TXT_RSA_WITH_AES_128_SHA ":" \
TLS1_TXT_ECDHE_ECDSA_WITH_DES_192_CBC3_SHA ":" \
TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA ":" \
SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA ":" \
SSL3_TXT_EDH_DSS_DES_192_CBC3_SHA ":" \
TLS1_TXT_ECDH_RSA_WITH_DES_192_CBC3_SHA ":" \
TLS1_TXT_ECDH_ECDSA_WITH_DES_192_CBC3_SHA ":" \
/*SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA ":"*/ \
SSL3_TXT_RSA_DES_192_CBC3_SHA)
/* SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA is commented out because it doesn't
* really exist; if I understand correctly, it's a bit of silliness that
* netscape did on its own before any standard for what they wanted was
* formally approved. Nonetheless, Firefox still uses it, so we need to
* fake it at some point soon. XXXX020 -NM */
#else
/* Ug. We don't have as many ciphers with openssl 0.9.7 as we'd like. Fix
* this list into something that sucks less. */
#define CLIENT_CIPHER_LIST \
(TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \
TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \
SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA ":" \
SSL3_TXT_RSA_RC4_128_SHA)
#endif
#ifndef V2_HANDSHAKE_CLIENT
#undef CLIENT_CIPHER_LIST
#define CLIENT_CIPHER_LIST (TLS1_TXT_DHE_RSA_WITH_AES_128_SHA ":" \
SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA)
#endif
/** Remove a reference to <b>ctx</b>, and free it if it has no more
* references. */
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);
}
}
/** Increase the reference count of <b>ctx</b>. */
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, 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 *nickname = NULL, *nn2 = NULL;
tor_tls_init();
nickname = crypto_random_hostname(8, 20, "www.", ".net");
nn2 = crypto_random_hostname(8, 20, "www.", ".net");
/* 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 (cert && !SSL_CTX_use_certificate(result->ctx,cert))
goto error;
X509_free(cert); /* We just added a reference to cert. */
cert=NULL;
if (idcert) {
X509_STORE *s = SSL_CTX_get_cert_store(result->ctx);
tor_assert(s);
X509_STORE_add_cert(s, idcert);
X509_free(idcert); /* The context now owns the reference to idcert */
idcert = NULL;
}
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);
tor_free(nickname);
tor_free(nn2);
return 0;
error:
tls_log_errors(LOG_WARN, "creating TLS context");
tor_free(nickname);
tor_free(nn2);
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
/** Return true iff the cipher list suggested by the client for <b>ssl</b> is
* a list that indicates that the client know how to do the v2 TLS connection
* handshake. */
static int
tor_tls_client_is_using_v2_ciphers(const SSL *ssl)
{
int i;
SSL_SESSION *session;
/* 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 0;
}
if (!session->ciphers) {
log_warn(LD_NET, "No ciphers on session");
return 0;
}
/* 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, TLS1_TXT_DHE_RSA_WITH_AES_256_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);
// return 1;
goto dump_list;
}
}
return 0;
dump_list:
{
smartlist_t *elts = smartlist_create();
char *s;
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);
smartlist_add(elts, (char*)ciphername);
}
s = smartlist_join_strings(elts, ":", 0, NULL);
log_info(LD_NET, "Got a non-version-1 cipher list. It is: '%s'", s);
tor_free(s);
smartlist_free(elts);
}
return 1;
}
/** Invoked when we're accepting a connection on <b>ssl</b>, and the connection
* changes state. We use this:
* <ul><li>To alter the state of the handshake partway through, so we
* do not send or request extra certificates in v2 handshakes.</li>
* <li>To detect renegotiation</li></ul>
*/
static void
tor_tls_server_info_callback(const SSL *ssl, int type, int val)
{
tor_tls_t *tls;
(void) val;
if (type != SSL_CB_ACCEPT_LOOP)
return;
if (ssl->state != SSL3_ST_SW_SRVR_HELLO_A)
return;
tls = tor_tls_get_by_ssl(ssl);
if (tls) {
/* Check whether we're watching for renegotiates. If so, this is one! */
if (tls->negotiated_callback)
tls->got_renegotiate = 1;
} else {
log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!");
}
/* Now check the cipher list. */
if (tor_tls_client_is_using_v2_ciphers(ssl)) {
/*XXXX_TLS keep this from happening more than once! */
/* 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);
if (tls) {
tls->wasV2Handshake = 1;
} else {
log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!");
}
}
}
#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;
}
if (!SSL_set_cipher_list(result->ssl,
isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) {
SSL_free(result->ssl);
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;
}
HT_INSERT(tlsmap, &tlsmap_root, result);
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;
}
/** Set <b>cb</b> to be called with argument <b>arg</b> whenever <b>tls</b>
* next gets a client-side renegotiate in the middle of a read. Do not
* invoke this function untile <em>after</em> initial handshaking is done!
*/
void
tor_tls_set_renegotiate_callback(tor_tls_t *tls,
void (*cb)(tor_tls_t *, void *arg),
void *arg)
{
tls->negotiated_callback = cb;
tls->callback_arg = arg;
tls->got_renegotiate = 0;
#ifdef V2_HANDSHAKE_SERVER
if (cb) {
SSL_set_info_callback(tls->ssl, tor_tls_server_info_callback);
} else {
SSL_set_info_callback(tls->ssl, NULL);
}
#endif
}
/** 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_tls_t *removed;
tor_assert(tls && tls->ssl);
removed = HT_REMOVE(tlsmap, &tlsmap_root, tls);
if (!removed) {
log_warn(LD_BUG, "Freeing a TLS that was not in the ssl->tls map.");
}
SSL_free(tls->ssl);
tls->ssl = NULL;
tls->negotiated_callback = 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->got_renegotiate) {
/* Renegotiation happened! */
log_notice(LD_NET, "Got a TLS renegotiation from %p", tls);
if (tls->negotiated_callback)
tls->negotiated_callback(tls, tls->callback_arg);
tls->got_renegotiate = 0;
}
#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;
if (tls->isServer) {
SSL_set_info_callback(tls->ssl, NULL);
SSL_set_verify(tls->ssl, SSL_VERIFY_NONE, always_accept_verify_cb);
/* There doesn't seem to be a clear OpenSSL API to clear mode flags. */
tls->ssl->mode &= ~SSL_MODE_NO_AUTO_CHAIN;
#ifdef V2_HANDSHAKE_SERVER
if (tor_tls_client_is_using_v2_ciphers(tls->ssl)) {
/* This check is redundant, but back when we did it in the callback,
* we might have not been able to look up the tor_tls_t if the code
* was buggy. Fixing that. */
if (!tls->wasV2Handshake) {
log_warn(LD_BUG, "For some reason, wasV2Handshake didn't"
" get set. Fixing that.");
}
tls->wasV2Handshake = 1;
} else {
tls->wasV2Handshake = 0;
}
#endif
} else {
#ifdef V2_HANDSHAKE_CLIENT
/* If we got no ID cert, we're a v2 handshake. */
X509 *cert = SSL_get_peer_certificate(tls->ssl);
STACK_OF(X509) *chain = SSL_get_peer_cert_chain(tls->ssl);
int n_certs = sk_X509_num(chain);
if (n_certs > 1 || (n_certs == 1 && cert != sk_X509_value(chain, 0)))
tls->wasV2Handshake = 0;
else {
log_notice(LD_NET, "I think I got a v2 handshake on %p!", tls);
tls->wasV2Handshake = 1;
}
if (cert)
X509_free(cert);
#endif
SSL_set_cipher_list(tls->ssl, SERVER_CIPHER_LIST);
}
}
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;
}
/** 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;
}
/** 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)
{
if (tls->isServer) {
#ifdef V2_HANDSHAKE_SERVER
return ! tls->wasV2Handshake;
#endif
} else {
#ifdef V2_HANDSHAKE_CLIENT
return ! tls->wasV2Handshake;
#endif
}
return 1;
}