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tor/src/common/tortls.c
Nick Mathewson d9ca4e20bd Merge branch 'feature_15055_v2'
2016-11-03 08:44:46 -04:00

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/* Copyright (c) 2003, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2016, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \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"
#define TORTLS_PRIVATE
#include <assert.h>
#ifdef _WIN32 /*wrkard for dtls1.h >= 0.9.8m of "#include <winsock.h>"*/
#include <winsock2.h>
#include <ws2tcpip.h>
#endif
#include "compat.h"
/* Some versions of OpenSSL declare SSL_get_selected_srtp_profile twice in
* srtp.h. Suppress the GCC warning so we can build with -Wredundant-decl. */
DISABLE_GCC_WARNING(redundant-decls)
#include <openssl/opensslv.h>
#include "crypto.h"
#ifdef OPENSSL_NO_EC
#error "We require OpenSSL with ECC support"
#endif
#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/bn.h>
#include <openssl/rsa.h>
ENABLE_GCC_WARNING(redundant-decls)
#define TORTLS_PRIVATE
#include "tortls.h"
#include "util.h"
#include "torlog.h"
#include "container.h"
#include <string.h>
#define X509_get_notBefore_const(cert) \
((const ASN1_TIME*) X509_get_notBefore((X509 *)cert))
#define X509_get_notAfter_const(cert) \
((const ASN1_TIME*) X509_get_notAfter((X509 *)cert))
/* Copied from or.h */
#define LEGAL_NICKNAME_CHARACTERS \
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
/** How long do identity certificates live? (sec) */
#define IDENTITY_CERT_LIFETIME (365*24*60*60)
#define ADDR(tls) (((tls) && (tls)->address) ? tls->address : "peer")
#if OPENSSL_VERSION_NUMBER < OPENSSL_V(1,0,0,'f')
/* This is a version of OpenSSL before 1.0.0f. It does not have
* the CVE-2011-4576 fix, and as such it can't use RELEASE_BUFFERS and
* SSL3 safely at the same time.
*/
#define DISABLE_SSL3_HANDSHAKE
#endif
/* We redefine these so that we can run correctly even if the vendor gives us
* a version of OpenSSL that does not match its header files. (Apple: I am
* looking at you.)
*/
#ifndef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
#define SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x00040000L
#endif
#ifndef SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
#define SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0x0010
#endif
/** Return values for tor_tls_classify_client_ciphers.
*
* @{
*/
/** An error occurred when examining the client ciphers */
#define CIPHERS_ERR -1
/** The client cipher list indicates that a v1 handshake was in use. */
#define CIPHERS_V1 1
/** The client cipher list indicates that the client is using the v2 or the
* v3 handshake, but that it is (probably!) lying about what ciphers it
* supports */
#define CIPHERS_V2 2
/** The client cipher list indicates that the client is using the v2 or the
* v3 handshake, and that it is telling the truth about what ciphers it
* supports */
#define CIPHERS_UNRESTRICTED 3
/** @} */
/** The ex_data index in which we store a pointer to an SSL object's
* corresponding tor_tls_t object. */
STATIC int tor_tls_object_ex_data_index = -1;
/** Helper: Allocate tor_tls_object_ex_data_index. */
STATIC void
tor_tls_allocate_tor_tls_object_ex_data_index(void)
{
if (tor_tls_object_ex_data_index == -1) {
tor_tls_object_ex_data_index =
SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
tor_assert(tor_tls_object_ex_data_index != -1);
}
}
/** Helper: given a SSL* pointer, return the tor_tls_t object using that
* pointer. */
STATIC tor_tls_t *
tor_tls_get_by_ssl(const SSL *ssl)
{
tor_tls_t *result = SSL_get_ex_data(ssl, tor_tls_object_ex_data_index);
if (result)
tor_assert(result->magic == TOR_TLS_MAGIC);
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 int check_cert_lifetime_internal(int severity, const X509 *cert,
time_t now,
int past_tolerance, int future_tolerance);
/** Global TLS contexts. We keep them here because nobody else needs
* to touch them.
*
* @{ */
STATIC tor_tls_context_t *server_tls_context = NULL;
STATIC tor_tls_context_t *client_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)
/** Write a description of the current state of <b>tls</b> into the
* <b>sz</b>-byte buffer at <b>buf</b>. */
void
tor_tls_get_state_description(tor_tls_t *tls, char *buf, size_t sz)
{
const char *ssl_state;
const char *tortls_state;
if (PREDICT_UNLIKELY(!tls || !tls->ssl)) {
strlcpy(buf, "(No SSL object)", sz);
return;
}
ssl_state = SSL_state_string_long(tls->ssl);
switch (tls->state) {
#define CASE(st) case TOR_TLS_ST_##st: tortls_state = " in "#st ; break
CASE(HANDSHAKE);
CASE(OPEN);
CASE(GOTCLOSE);
CASE(SENTCLOSE);
CASE(CLOSED);
CASE(RENEGOTIATE);
#undef CASE
case TOR_TLS_ST_BUFFEREVENT:
tortls_state = "";
break;
default:
tortls_state = " in unknown TLS state";
break;
}
tor_snprintf(buf, sz, "%s%s", ssl_state, tortls_state);
}
/** Log a single error <b>err</b> as returned by ERR_get_error(), which was
* received while performing an operation <b>doing</b> on <b>tls</b>. Log
* the message at <b>severity</b>, in log domain <b>domain</b>. */
void
tor_tls_log_one_error(tor_tls_t *tls, unsigned long err,
int severity, int domain, const char *doing)
{
const char *state = NULL, *addr;
const char *msg, *lib, *func;
state = (tls && tls->ssl)?SSL_state_string_long(tls->ssl):"---";
addr = tls ? tls->address : NULL;
/* Some errors are known-benign, meaning they are the fault of the other
* side of the connection. The caller doesn't know this, so override the
* priority for those cases. */
switch (ERR_GET_REASON(err)) {
case SSL_R_HTTP_REQUEST:
case SSL_R_HTTPS_PROXY_REQUEST:
case SSL_R_RECORD_LENGTH_MISMATCH:
#ifndef OPENSSL_1_1_API
case SSL_R_RECORD_TOO_LARGE:
#endif
case SSL_R_UNKNOWN_PROTOCOL:
case SSL_R_UNSUPPORTED_PROTOCOL:
severity = LOG_INFO;
break;
default:
break;
}
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 (!lib) lib = "(null)";
if (!func) func = "(null)";
if (doing) {
tor_log(severity, domain, "TLS error while %s%s%s: %s (in %s:%s:%s)",
doing, addr?" with ":"", addr?addr:"",
msg, lib, func, state);
} else {
tor_log(severity, domain, "TLS error%s%s: %s (in %s:%s:%s)",
addr?" with ":"", addr?addr:"",
msg, lib, func, state);
}
}
/** Log all pending tls errors at level <b>severity</b> in log domain
* <b>domain</b>. Use <b>doing</b> to describe our current activities.
*/
STATIC void
tls_log_errors(tor_tls_t *tls, int severity, int domain, const char *doing)
{
unsigned long err;
while ((err = ERR_get_error()) != 0) {
tor_tls_log_one_error(tls, err, severity, domain, doing);
}
}
/** Convert an errno (or a WSAerrno on windows) into a TOR_TLS_* error
* code. */
STATIC int
tor_errno_to_tls_error(int e)
{
switch (e) {
case SOCK_ERRNO(ECONNRESET): // most common
return TOR_TLS_ERROR_CONNRESET;
case SOCK_ERRNO(ETIMEDOUT):
return TOR_TLS_ERROR_TIMEOUT;
case SOCK_ERRNO(EHOSTUNREACH):
case SOCK_ERRNO(ENETUNREACH):
return TOR_TLS_ERROR_NO_ROUTE;
case SOCK_ERRNO(ECONNREFUSED):
return TOR_TLS_ERROR_CONNREFUSED; // least common
default:
return TOR_TLS_ERROR_MISC;
}
}
/** 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 domain)
{
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) {
tor_log(severity, LD_NET, "TLS error: unexpected close while %s (%s)",
doing, SSL_state_string_long(tls->ssl));
tor_error = TOR_TLS_ERROR_IO;
} else {
int e = tor_socket_errno(tls->socket);
tor_log(severity, LD_NET,
"TLS error: <syscall error while %s> (errno=%d: %s; state=%s)",
doing, e, tor_socket_strerror(e),
SSL_state_string_long(tls->ssl));
tor_error = tor_errno_to_tls_error(e);
}
tls_log_errors(tls, severity, domain, doing);
return tor_error;
case SSL_ERROR_ZERO_RETURN:
if (extra&CATCH_ZERO)
return TOR_TLS_ZERORETURN_;
tor_log(severity, LD_NET, "TLS connection closed while %s in state %s",
doing, SSL_state_string_long(tls->ssl));
tls_log_errors(tls, severity, domain, doing);
return TOR_TLS_CLOSE;
default:
tls_log_errors(tls, severity, domain, doing);
return TOR_TLS_ERROR_MISC;
}
}
/** Initialize OpenSSL, unless it has already been initialized.
*/
static void
tor_tls_init(void)
{
check_no_tls_errors();
if (!tls_library_is_initialized) {
SSL_library_init();
SSL_load_error_strings();
#if (SIZEOF_VOID_P >= 8 && \
OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,0,1))
long version = OpenSSL_version_num();
/* LCOV_EXCL_START : we can't test these lines on the same machine */
if (version >= OPENSSL_V_SERIES(1,0,1)) {
/* Warn if we could *almost* be running with much faster ECDH.
If we're built for a 64-bit target, using OpenSSL 1.0.1, but we
don't have one of the built-in __uint128-based speedups, we are
just one build operation away from an accelerated handshake.
(We could be looking at OPENSSL_NO_EC_NISTP_64_GCC_128 instead of
doing this test, but that gives compile-time options, not runtime
behavior.)
*/
EC_KEY *key = EC_KEY_new_by_curve_name(NID_X9_62_prime256v1);
const EC_GROUP *g = key ? EC_KEY_get0_group(key) : NULL;
const EC_METHOD *m = g ? EC_GROUP_method_of(g) : NULL;
const int warn = (m == EC_GFp_simple_method() ||
m == EC_GFp_mont_method() ||
m == EC_GFp_nist_method());
EC_KEY_free(key);
if (warn)
log_notice(LD_GENERAL, "We were built to run on a 64-bit CPU, with "
"OpenSSL 1.0.1 or later, but with a version of OpenSSL "
"that apparently lacks accelerated support for the NIST "
"P-224 and P-256 groups. Building openssl with such "
"support (using the enable-ec_nistp_64_gcc_128 option "
"when configuring it) would make ECDH much faster.");
}
/* LCOV_EXCL_STOP */
#endif
tor_tls_allocate_tor_tls_object_ex_data_index();
tls_library_is_initialized = 1;
}
}
/** Free all global TLS structures. */
void
tor_tls_free_all(void)
{
check_no_tls_errors();
if (server_tls_context) {
tor_tls_context_t *ctx = server_tls_context;
server_tls_context = NULL;
tor_tls_context_decref(ctx);
}
if (client_tls_context) {
tor_tls_context_t *ctx = client_tls_context;
client_tls_context = NULL;
tor_tls_context_decref(ctx);
}
}
/** 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;
/* LCOV_EXCL_BR_START : these branches will only fail on OOM errors */
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;
/* LCOV_EXCL_BR_STOP */
return name;
error:
/* LCOV_EXCL_START : these lines will only execute on out of memory errors*/
X509_NAME_free(name);
return NULL;
/* LCOV_EXCL_STOP */
}
/** 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 some time in the past.
*
* Return a certificate on success, NULL on failure.
*/
MOCK_IMPL(STATIC X509 *,
tor_tls_create_certificate,(crypto_pk_t *rsa,
crypto_pk_t *rsa_sign,
const char *cname,
const char *cname_sign,
unsigned int cert_lifetime))
{
/* OpenSSL generates self-signed certificates with random 64-bit serial
* numbers, so let's do that too. */
#define SERIAL_NUMBER_SIZE 8
time_t start_time, end_time;
BIGNUM *serial_number = NULL;
unsigned char serial_tmp[SERIAL_NUMBER_SIZE];
EVP_PKEY *sign_pkey = NULL, *pkey=NULL;
X509 *x509 = NULL;
X509_NAME *name = NULL, *name_issuer=NULL;
tor_tls_init();
/* Make sure we're part-way through the certificate lifetime, rather
* than having it start right now. Don't choose quite uniformly, since
* then we might pick a time where we're about to expire. Lastly, be
* sure to start on a day boundary. */
time_t now = time(NULL);
start_time = crypto_rand_time_range(now - cert_lifetime, now) + 2*24*3600;
start_time -= start_time % (24*3600);
tor_assert(rsa);
tor_assert(cname);
tor_assert(rsa_sign);
tor_assert(cname_sign);
if (!(sign_pkey = crypto_pk_get_evp_pkey_(rsa_sign,1)))
goto error;
if (!(pkey = crypto_pk_get_evp_pkey_(rsa,0)))
goto error;
if (!(x509 = X509_new()))
goto error;
if (!(X509_set_version(x509, 2)))
goto error;
{ /* our serial number is 8 random bytes. */
crypto_rand((char *)serial_tmp, sizeof(serial_tmp));
if (!(serial_number = BN_bin2bn(serial_tmp, sizeof(serial_tmp), NULL)))
goto error;
if (!(BN_to_ASN1_INTEGER(serial_number, X509_get_serialNumber(x509))))
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_sha256()))
goto error;
goto done;
error:
if (x509) {
X509_free(x509);
x509 = NULL;
}
done:
tls_log_errors(NULL, LOG_WARN, LD_NET, "generating certificate");
if (sign_pkey)
EVP_PKEY_free(sign_pkey);
if (pkey)
EVP_PKEY_free(pkey);
if (serial_number)
BN_clear_free(serial_number);
if (name)
X509_NAME_free(name);
if (name_issuer)
X509_NAME_free(name_issuer);
return x509;
#undef SERIAL_NUMBER_SIZE
}
/** List of ciphers that servers should select from when the client might be
* claiming extra unsupported ciphers in order to avoid fingerprinting. */
#define SERVER_CIPHER_LIST \
(TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":" \
TLS1_TXT_DHE_RSA_WITH_AES_128_SHA)
/** List of ciphers that servers should select from when we actually have
* our choice of what cipher to use. */
static const char UNRESTRICTED_SERVER_CIPHER_LIST[] =
/* This list is autogenerated with the gen_server_ciphers.py script;
* don't hand-edit it. */
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384
TLS1_TXT_ECDHE_RSA_WITH_AES_256_GCM_SHA384 ":"
#endif
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256
TLS1_TXT_ECDHE_RSA_WITH_AES_128_GCM_SHA256 ":"
#endif
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384
TLS1_TXT_ECDHE_RSA_WITH_AES_256_SHA384 ":"
#endif
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256
TLS1_TXT_ECDHE_RSA_WITH_AES_128_SHA256 ":"
#endif
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA
TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA ":"
#endif
#ifdef TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA
TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA ":"
#endif
#ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384
TLS1_TXT_DHE_RSA_WITH_AES_256_GCM_SHA384 ":"
#endif
#ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256
TLS1_TXT_DHE_RSA_WITH_AES_128_GCM_SHA256 ":"
#endif
#ifdef TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256
TLS1_TXT_DHE_RSA_WITH_AES_256_SHA256 ":"
#endif
#ifdef TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256
TLS1_TXT_DHE_RSA_WITH_AES_128_SHA256 ":"
#endif
/* Required */
TLS1_TXT_DHE_RSA_WITH_AES_256_SHA ":"
/* Required */
TLS1_TXT_DHE_RSA_WITH_AES_128_SHA
;
/* Note: to set up your own private testing network with link crypto
* disabled, set your Tors' 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. */
#define CIPHER(id, name) name ":"
#define XCIPHER(id, name)
/** List of ciphers that clients should advertise, omitting items that
* our OpenSSL doesn't know about. */
static const char CLIENT_CIPHER_LIST[] =
#include "ciphers.inc"
/* Tell it not to use SSLv2 ciphers, so that it can select an SSLv3 version
* of any cipher we say. */
"!SSLv2"
;
#undef CIPHER
#undef XCIPHER
/** Free all storage held in <b>cert</b> */
void
tor_x509_cert_free(tor_x509_cert_t *cert)
{
if (! cert)
return;
if (cert->cert)
X509_free(cert->cert);
tor_free(cert->encoded);
memwipe(cert, 0x03, sizeof(*cert));
/* LCOV_EXCL_BR_START since cert will never be NULL here */
tor_free(cert);
/* LCOV_EXCL_BR_STOP */
}
/**
* Allocate a new tor_x509_cert_t to hold the certificate "x509_cert".
*
* Steals a reference to x509_cert.
*/
MOCK_IMPL(STATIC tor_x509_cert_t *,
tor_x509_cert_new,(X509 *x509_cert))
{
tor_x509_cert_t *cert;
EVP_PKEY *pkey;
RSA *rsa;
int length;
unsigned char *buf = NULL;
if (!x509_cert)
return NULL;
length = i2d_X509(x509_cert, &buf);
cert = tor_malloc_zero(sizeof(tor_x509_cert_t));
if (length <= 0 || buf == NULL) {
/* LCOV_EXCL_START for the same reason as the exclusion above */
tor_free(cert);
log_err(LD_CRYPTO, "Couldn't get length of encoded x509 certificate");
X509_free(x509_cert);
return NULL;
/* LCOV_EXCL_STOP */
}
cert->encoded_len = (size_t) length;
cert->encoded = tor_malloc(length);
memcpy(cert->encoded, buf, length);
OPENSSL_free(buf);
cert->cert = x509_cert;
crypto_common_digests(&cert->cert_digests,
(char*)cert->encoded, cert->encoded_len);
if ((pkey = X509_get_pubkey(x509_cert)) &&
(rsa = EVP_PKEY_get1_RSA(pkey))) {
crypto_pk_t *pk = crypto_new_pk_from_rsa_(rsa);
crypto_pk_get_common_digests(pk, &cert->pkey_digests);
cert->pkey_digests_set = 1;
crypto_pk_free(pk);
EVP_PKEY_free(pkey);
}
return cert;
}
/** Return a copy of <b>cert</b> */
tor_x509_cert_t *
tor_x509_cert_dup(const tor_x509_cert_t *cert)
{
return tor_x509_cert_new(X509_dup(cert->cert));
}
/** Read a DER-encoded X509 cert, of length exactly <b>certificate_len</b>,
* from a <b>certificate</b>. Return a newly allocated tor_x509_cert_t on
* success and NULL on failure. */
tor_x509_cert_t *
tor_x509_cert_decode(const uint8_t *certificate, size_t certificate_len)
{
X509 *x509;
const unsigned char *cp = (const unsigned char *)certificate;
tor_x509_cert_t *newcert;
tor_assert(certificate);
check_no_tls_errors();
if (certificate_len > INT_MAX)
goto err;
x509 = d2i_X509(NULL, &cp, (int)certificate_len);
if (!x509)
goto err; /* Couldn't decode */
if (cp - certificate != (int)certificate_len) {
X509_free(x509);
goto err; /* Didn't use all the bytes */
}
newcert = tor_x509_cert_new(x509);
if (!newcert) {
goto err;
}
if (newcert->encoded_len != certificate_len ||
fast_memneq(newcert->encoded, certificate, certificate_len)) {
/* Cert wasn't in DER */
tor_x509_cert_free(newcert);
goto err;
}
return newcert;
err:
tls_log_errors(NULL, LOG_INFO, LD_CRYPTO, "decoding a certificate");
return NULL;
}
/** Set *<b>encoded_out</b> and *<b>size_out</b> to <b>cert</b>'s encoded DER
* representation and length, respectively. */
void
tor_x509_cert_get_der(const tor_x509_cert_t *cert,
const uint8_t **encoded_out, size_t *size_out)
{
tor_assert(cert);
tor_assert(encoded_out);
tor_assert(size_out);
*encoded_out = cert->encoded;
*size_out = cert->encoded_len;
}
/** Return a set of digests for the public key in <b>cert</b>, or NULL if this
* cert's public key is not one we know how to take the digest of. */
const common_digests_t *
tor_x509_cert_get_id_digests(const tor_x509_cert_t *cert)
{
if (cert->pkey_digests_set)
return &cert->pkey_digests;
else
return NULL;
}
/** Return a set of digests for the public key in <b>cert</b>. */
const common_digests_t *
tor_x509_cert_get_cert_digests(const tor_x509_cert_t *cert)
{
return &cert->cert_digests;
}
/** 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);
tor_x509_cert_free(ctx->my_link_cert);
tor_x509_cert_free(ctx->my_id_cert);
tor_x509_cert_free(ctx->my_auth_cert);
crypto_pk_free(ctx->link_key);
crypto_pk_free(ctx->auth_key);
/* LCOV_EXCL_BR_START since ctx will never be NULL here */
tor_free(ctx);
/* LCOV_EXCL_BR_STOP */
}
}
/** Set *<b>link_cert_out</b> and *<b>id_cert_out</b> to the link certificate
* and ID certificate that we're currently using for our V3 in-protocol
* handshake's certificate chain. If <b>server</b> is true, provide the certs
* that we use in server mode (auth, ID); otherwise, provide the certs that we
* use in client mode. (link, ID) */
int
tor_tls_get_my_certs(int server,
const tor_x509_cert_t **link_cert_out,
const tor_x509_cert_t **id_cert_out)
{
tor_tls_context_t *ctx = server ? server_tls_context : client_tls_context;
if (! ctx)
return -1;
if (link_cert_out)
*link_cert_out = server ? ctx->my_link_cert : ctx->my_auth_cert;
if (id_cert_out)
*id_cert_out = ctx->my_id_cert;
return 0;
}
/**
* Return the authentication key that we use to authenticate ourselves as a
* client in the V3 in-protocol handshake.
*/
crypto_pk_t *
tor_tls_get_my_client_auth_key(void)
{
if (! client_tls_context)
return NULL;
return client_tls_context->auth_key;
}
/**
* Return a newly allocated copy of the public key that a certificate
* certifies. Watch out! This returns NULL if the cert's key is not RSA.
*/
crypto_pk_t *
tor_tls_cert_get_key(tor_x509_cert_t *cert)
{
crypto_pk_t *result = NULL;
EVP_PKEY *pkey = X509_get_pubkey(cert->cert);
RSA *rsa;
if (!pkey)
return NULL;
rsa = EVP_PKEY_get1_RSA(pkey);
if (!rsa) {
EVP_PKEY_free(pkey);
return NULL;
}
result = crypto_new_pk_from_rsa_(rsa);
EVP_PKEY_free(pkey);
return result;
}
/** Return true iff the other side of <b>tls</b> has authenticated to us, and
* the key certified in <b>cert</b> is the same as the key they used to do it.
*/
MOCK_IMPL(int,
tor_tls_cert_matches_key,(const tor_tls_t *tls, const tor_x509_cert_t *cert))
{
X509 *peercert = SSL_get_peer_certificate(tls->ssl);
EVP_PKEY *link_key = NULL, *cert_key = NULL;
int result;
if (!peercert)
return 0;
link_key = X509_get_pubkey(peercert);
cert_key = X509_get_pubkey(cert->cert);
result = link_key && cert_key && EVP_PKEY_cmp(cert_key, link_key) == 1;
X509_free(peercert);
if (link_key)
EVP_PKEY_free(link_key);
if (cert_key)
EVP_PKEY_free(cert_key);
return result;
}
/** Check whether <b>cert</b> is well-formed, currently live, and correctly
* signed by the public key in <b>signing_cert</b>. If <b>check_rsa_1024</b>,
* make sure that it has an RSA key with 1024 bits; otherwise, just check that
* the key is long enough. Return 1 if the cert is good, and 0 if it's bad or
* we couldn't check it. */
int
tor_tls_cert_is_valid(int severity,
const tor_x509_cert_t *cert,
const tor_x509_cert_t *signing_cert,
time_t now,
int check_rsa_1024)
{
check_no_tls_errors();
EVP_PKEY *cert_key;
int r, key_ok = 0;
if (!signing_cert || !cert)
goto bad;
EVP_PKEY *signing_key = X509_get_pubkey(signing_cert->cert);
if (!signing_key)
goto bad;
r = X509_verify(cert->cert, signing_key);
EVP_PKEY_free(signing_key);
if (r <= 0)
goto bad;
/* okay, the signature checked out right. Now let's check the check the
* lifetime. */
if (check_cert_lifetime_internal(severity, cert->cert, now,
48*60*60, 30*24*60*60) < 0)
goto bad;
cert_key = X509_get_pubkey(cert->cert);
if (check_rsa_1024 && cert_key) {
RSA *rsa = EVP_PKEY_get1_RSA(cert_key);
#ifdef OPENSSL_1_1_API
if (rsa && RSA_bits(rsa) == 1024)
#else
if (rsa && BN_num_bits(rsa->n) == 1024)
#endif
key_ok = 1;
if (rsa)
RSA_free(rsa);
} else if (cert_key) {
int min_bits = 1024;
#ifdef EVP_PKEY_EC
if (EVP_PKEY_base_id(cert_key) == EVP_PKEY_EC)
min_bits = 128;
#endif
if (EVP_PKEY_bits(cert_key) >= min_bits)
key_ok = 1;
}
EVP_PKEY_free(cert_key);
if (!key_ok)
goto bad;
/* XXXX compare DNs or anything? */
return 1;
bad:
tls_log_errors(NULL, LOG_INFO, LD_CRYPTO, "checking a certificate");
return 0;
}
/** Increase the reference count of <b>ctx</b>. */
static void
tor_tls_context_incref(tor_tls_context_t *ctx)
{
++ctx->refcnt;
}
/** Create new global client and server TLS contexts.
*
* If <b>server_identity</b> is NULL, this will not generate a server
* TLS context. If TOR_TLS_CTX_IS_PUBLIC_SERVER is set in <b>flags</b>, use
* the same TLS context for incoming and outgoing connections, and
* ignore <b>client_identity</b>. If one of TOR_TLS_CTX_USE_ECDHE_P{224,256}
* is set in <b>flags</b>, use that ECDHE group if possible; otherwise use
* the default ECDHE group. */
int
tor_tls_context_init(unsigned flags,
crypto_pk_t *client_identity,
crypto_pk_t *server_identity,
unsigned int key_lifetime)
{
int rv1 = 0;
int rv2 = 0;
const int is_public_server = flags & TOR_TLS_CTX_IS_PUBLIC_SERVER;
check_no_tls_errors();
if (is_public_server) {
tor_tls_context_t *new_ctx;
tor_tls_context_t *old_ctx;
tor_assert(server_identity != NULL);
rv1 = tor_tls_context_init_one(&server_tls_context,
server_identity,
key_lifetime, flags, 0);
if (rv1 >= 0) {
new_ctx = server_tls_context;
tor_tls_context_incref(new_ctx);
old_ctx = client_tls_context;
client_tls_context = new_ctx;
if (old_ctx != NULL) {
tor_tls_context_decref(old_ctx);
}
}
} else {
if (server_identity != NULL) {
rv1 = tor_tls_context_init_one(&server_tls_context,
server_identity,
key_lifetime,
flags,
0);
} else {
tor_tls_context_t *old_ctx = server_tls_context;
server_tls_context = NULL;
if (old_ctx != NULL) {
tor_tls_context_decref(old_ctx);
}
}
rv2 = tor_tls_context_init_one(&client_tls_context,
client_identity,
key_lifetime,
flags,
1);
}
tls_log_errors(NULL, LOG_WARN, LD_CRYPTO, "constructing a TLS context");
return MIN(rv1, rv2);
}
/** Create a new global TLS context.
*
* 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.
*/
STATIC int
tor_tls_context_init_one(tor_tls_context_t **ppcontext,
crypto_pk_t *identity,
unsigned int key_lifetime,
unsigned int flags,
int is_client)
{
tor_tls_context_t *new_ctx = tor_tls_context_new(identity,
key_lifetime,
flags,
is_client);
tor_tls_context_t *old_ctx = *ppcontext;
if (new_ctx != NULL) {
*ppcontext = new_ctx;
/* Free the old context if one existed. */
if (old_ctx != NULL) {
/* This is safe even if there are open connections: we reference-
* count tor_tls_context_t objects. */
tor_tls_context_decref(old_ctx);
}
}
return ((new_ctx != NULL) ? 0 : -1);
}
/** The group we should use for ecdhe when none was selected. */
#define NID_tor_default_ecdhe_group NID_X9_62_prime256v1
#define RSA_LINK_KEY_BITS 2048
/** 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.
*/
STATIC tor_tls_context_t *
tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
unsigned flags, int is_client)
{
crypto_pk_t *rsa = NULL, *rsa_auth = NULL;
EVP_PKEY *pkey = NULL;
tor_tls_context_t *result = NULL;
X509 *cert = NULL, *idcert = NULL, *authcert = NULL;
char *nickname = NULL, *nn2 = NULL;
tor_tls_init();
nickname = crypto_random_hostname(8, 20, "www.", ".net");
#ifdef DISABLE_V3_LINKPROTO_SERVERSIDE
nn2 = crypto_random_hostname(8, 20, "www.", ".net");
#else
nn2 = crypto_random_hostname(8, 20, "www.", ".com");
#endif
/* Generate short-term RSA key for use with TLS. */
if (!(rsa = crypto_pk_new()))
goto error;
if (crypto_pk_generate_key_with_bits(rsa, RSA_LINK_KEY_BITS)<0)
goto error;
if (!is_client) {
/* Generate short-term RSA key for use in the in-protocol ("v3")
* authentication handshake. */
if (!(rsa_auth = crypto_pk_new()))
goto error;
if (crypto_pk_generate_key(rsa_auth)<0)
goto error;
/* Create a link 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);
/* Create an authentication certificate signed by identity key. */
authcert = tor_tls_create_certificate(rsa_auth, identity, nickname, nn2,
key_lifetime);
if (!cert || !idcert || !authcert) {
log_warn(LD_CRYPTO, "Error creating certificate");
goto error;
}
}
result = tor_malloc_zero(sizeof(tor_tls_context_t));
result->refcnt = 1;
if (!is_client) {
result->my_link_cert = tor_x509_cert_new(X509_dup(cert));
result->my_id_cert = tor_x509_cert_new(X509_dup(idcert));
result->my_auth_cert = tor_x509_cert_new(X509_dup(authcert));
if (!result->my_link_cert || !result->my_id_cert || !result->my_auth_cert)
goto error;
result->link_key = crypto_pk_dup_key(rsa);
result->auth_key = crypto_pk_dup_key(rsa_auth);
}
#if 0
/* Tell OpenSSL to only use TLS1. This may have subtly different results
* from SSLv23_method() with SSLv2 and SSLv3 disabled, so we need to do some
* investigation before we consider adjusting it. It should be compatible
* with existing Tors. */
if (!(result->ctx = SSL_CTX_new(TLSv1_method())))
goto error;
#endif
/* Tell OpenSSL to use TLS 1.0 or later but not SSL2 or SSL3. */
#ifdef HAVE_TLS_METHOD
if (!(result->ctx = SSL_CTX_new(TLS_method())))
goto error;
#else
if (!(result->ctx = SSL_CTX_new(SSLv23_method())))
goto error;
#endif
SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv2);
SSL_CTX_set_options(result->ctx, SSL_OP_NO_SSLv3);
/* Prefer the server's ordering of ciphers: the client's ordering has
* historically been chosen for fingerprinting resistance. */
SSL_CTX_set_options(result->ctx, SSL_OP_CIPHER_SERVER_PREFERENCE);
/* Disable TLS tickets if they're supported. We never want to use them;
* using them can make our perfect forward secrecy a little worse, *and*
* create an opportunity to fingerprint us (since it's unusual to use them
* with TLS sessions turned off).
*
* In 0.2.4, clients advertise support for them though, to avoid a TLS
* distinguishability vector. This can give us worse PFS, though, if we
* get a server that doesn't set SSL_OP_NO_TICKET. With luck, there will
* be few such servers by the time 0.2.4 is more stable.
*/
#ifdef SSL_OP_NO_TICKET
if (! is_client) {
SSL_CTX_set_options(result->ctx, SSL_OP_NO_TICKET);
}
#endif
SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_DH_USE);
SSL_CTX_set_options(result->ctx, SSL_OP_SINGLE_ECDH_USE);
#ifdef SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION
SSL_CTX_set_options(result->ctx,
SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION);
#endif
/* Yes, we know what we are doing here. No, we do not treat a renegotiation
* as authenticating any earlier-received data.
*/
{
SSL_CTX_set_options(result->ctx,
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);
}
#ifdef SSL_OP_NO_COMPRESSION
SSL_CTX_set_options(result->ctx, SSL_OP_NO_COMPRESSION);
#endif
#if OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(1,1,0)
#ifndef OPENSSL_NO_COMP
/* Don't actually allow compression; it uses ram and time, but the data
* we transmit is all encrypted anyway. */
if (result->ctx->comp_methods)
result->ctx->comp_methods = NULL;
#endif
#endif
#ifdef SSL_MODE_RELEASE_BUFFERS
SSL_CTX_set_mode(result->ctx, SSL_MODE_RELEASE_BUFFERS);
#endif
if (! is_client) {
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);
if (!is_client) {
tor_assert(rsa);
if (!(pkey = crypto_pk_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;
}
{
crypto_dh_t *dh = crypto_dh_new(DH_TYPE_TLS);
tor_assert(dh);
SSL_CTX_set_tmp_dh(result->ctx, crypto_dh_get_dh_(dh));
crypto_dh_free(dh);
}
if (! is_client) {
int nid;
EC_KEY *ec_key;
if (flags & TOR_TLS_CTX_USE_ECDHE_P224)
nid = NID_secp224r1;
else if (flags & TOR_TLS_CTX_USE_ECDHE_P256)
nid = NID_X9_62_prime256v1;
else
nid = NID_tor_default_ecdhe_group;
/* Use P-256 for ECDHE. */
ec_key = EC_KEY_new_by_curve_name(nid);
if (ec_key != NULL) /*XXXX Handle errors? */
SSL_CTX_set_tmp_ecdh(result->ctx, ec_key);
EC_KEY_free(ec_key);
}
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);
if (rsa)
crypto_pk_free(rsa);
if (rsa_auth)
crypto_pk_free(rsa_auth);
X509_free(authcert);
tor_free(nickname);
tor_free(nn2);
return result;
error:
tls_log_errors(NULL, LOG_WARN, LD_NET, "creating TLS context");
tor_free(nickname);
tor_free(nn2);
if (pkey)
EVP_PKEY_free(pkey);
if (rsa)
crypto_pk_free(rsa);
if (rsa_auth)
crypto_pk_free(rsa_auth);
if (result)
tor_tls_context_decref(result);
if (cert)
X509_free(cert);
if (idcert)
X509_free(idcert);
if (authcert)
X509_free(authcert);
return NULL;
}
/** Invoked when a TLS state changes: log the change at severity 'debug' */
STATIC void
tor_tls_debug_state_callback(const SSL *ssl, int type, int val)
{
/* LCOV_EXCL_START since this depends on whether debug is captured or not */
log_debug(LD_HANDSHAKE, "SSL %p is now in state %s [type=%d,val=%d].",
ssl, SSL_state_string_long(ssl), type, val);
/* LCOV_EXCL_STOP */
}
/* Return the name of the negotiated ciphersuite in use on <b>tls</b> */
const char *
tor_tls_get_ciphersuite_name(tor_tls_t *tls)
{
return SSL_get_cipher(tls->ssl);
}
/* Here's the old V2 cipher list we sent from 0.2.1.1-alpha up to
* 0.2.3.17-beta. If a client is using this list, we can't believe the ciphers
* that it claims to support. We'll prune this list to remove the ciphers
* *we* don't recognize. */
STATIC uint16_t v2_cipher_list[] = {
0xc00a, /* TLS1_TXT_ECDHE_ECDSA_WITH_AES_256_CBC_SHA */
0xc014, /* TLS1_TXT_ECDHE_RSA_WITH_AES_256_CBC_SHA */
0x0039, /* TLS1_TXT_DHE_RSA_WITH_AES_256_SHA */
0x0038, /* TLS1_TXT_DHE_DSS_WITH_AES_256_SHA */
0xc00f, /* TLS1_TXT_ECDH_RSA_WITH_AES_256_CBC_SHA */
0xc005, /* TLS1_TXT_ECDH_ECDSA_WITH_AES_256_CBC_SHA */
0x0035, /* TLS1_TXT_RSA_WITH_AES_256_SHA */
0xc007, /* TLS1_TXT_ECDHE_ECDSA_WITH_RC4_128_SHA */
0xc009, /* TLS1_TXT_ECDHE_ECDSA_WITH_AES_128_CBC_SHA */
0xc011, /* TLS1_TXT_ECDHE_RSA_WITH_RC4_128_SHA */
0xc013, /* TLS1_TXT_ECDHE_RSA_WITH_AES_128_CBC_SHA */
0x0033, /* TLS1_TXT_DHE_RSA_WITH_AES_128_SHA */
0x0032, /* TLS1_TXT_DHE_DSS_WITH_AES_128_SHA */
0xc00c, /* TLS1_TXT_ECDH_RSA_WITH_RC4_128_SHA */
0xc00e, /* TLS1_TXT_ECDH_RSA_WITH_AES_128_CBC_SHA */
0xc002, /* TLS1_TXT_ECDH_ECDSA_WITH_RC4_128_SHA */
0xc004, /* TLS1_TXT_ECDH_ECDSA_WITH_AES_128_CBC_SHA */
0x0004, /* SSL3_TXT_RSA_RC4_128_MD5 */
0x0005, /* SSL3_TXT_RSA_RC4_128_SHA */
0x002f, /* TLS1_TXT_RSA_WITH_AES_128_SHA */
0xc008, /* TLS1_TXT_ECDHE_ECDSA_WITH_DES_192_CBC3_SHA */
0xc012, /* TLS1_TXT_ECDHE_RSA_WITH_DES_192_CBC3_SHA */
0x0016, /* SSL3_TXT_EDH_RSA_DES_192_CBC3_SHA */
0x0013, /* SSL3_TXT_EDH_DSS_DES_192_CBC3_SHA */
0xc00d, /* TLS1_TXT_ECDH_RSA_WITH_DES_192_CBC3_SHA */
0xc003, /* TLS1_TXT_ECDH_ECDSA_WITH_DES_192_CBC3_SHA */
0xfeff, /* SSL3_TXT_RSA_FIPS_WITH_3DES_EDE_CBC_SHA */
0x000a, /* SSL3_TXT_RSA_DES_192_CBC3_SHA */
0
};
/** Have we removed the unrecognized ciphers from v2_cipher_list yet? */
static int v2_cipher_list_pruned = 0;
/** Return 0 if <b>m</b> does not support the cipher with ID <b>cipher</b>;
* return 1 if it does support it, or if we have no way to tell. */
STATIC int
find_cipher_by_id(const SSL *ssl, const SSL_METHOD *m, uint16_t cipher)
{
const SSL_CIPHER *c;
#ifdef HAVE_SSL_CIPHER_FIND
(void) m;
{
unsigned char cipherid[3];
tor_assert(ssl);
set_uint16(cipherid, htons(cipher));
cipherid[2] = 0; /* If ssl23_get_cipher_by_char finds no cipher starting
* with a two-byte 'cipherid', it may look for a v2
* cipher with the appropriate 3 bytes. */
c = SSL_CIPHER_find((SSL*)ssl, cipherid);
if (c)
tor_assert((SSL_CIPHER_get_id(c) & 0xffff) == cipher);
return c != NULL;
}
#else
# if defined(HAVE_STRUCT_SSL_METHOD_ST_GET_CIPHER_BY_CHAR)
if (m && m->get_cipher_by_char) {
unsigned char cipherid[3];
set_uint16(cipherid, htons(cipher));
cipherid[2] = 0; /* If ssl23_get_cipher_by_char finds no cipher starting
* with a two-byte 'cipherid', it may look for a v2
* cipher with the appropriate 3 bytes. */
c = m->get_cipher_by_char(cipherid);
if (c)
tor_assert((c->id & 0xffff) == cipher);
return c != NULL;
}
# endif
# ifndef OPENSSL_1_1_API
if (m && m->get_cipher && m->num_ciphers) {
/* It would seem that some of the "let's-clean-up-openssl" forks have
* removed the get_cipher_by_char function. Okay, so now you get a
* quadratic search.
*/
int i;
for (i = 0; i < m->num_ciphers(); ++i) {
c = m->get_cipher(i);
if (c && (c->id & 0xffff) == cipher) {
return 1;
}
}
return 0;
}
# endif
(void) ssl;
(void) m;
(void) cipher;
return 1; /* No way to search */
#endif
}
/** Remove from v2_cipher_list every cipher that we don't support, so that
* comparing v2_cipher_list to a client's cipher list will give a sensible
* result. */
static void
prune_v2_cipher_list(const SSL *ssl)
{
uint16_t *inp, *outp;
#ifdef HAVE_TLS_METHOD
const SSL_METHOD *m = TLS_method();
#else
const SSL_METHOD *m = SSLv23_method();
#endif
inp = outp = v2_cipher_list;
while (*inp) {
if (find_cipher_by_id(ssl, m, *inp)) {
*outp++ = *inp++;
} else {
inp++;
}
}
*outp = 0;
v2_cipher_list_pruned = 1;
}
/** Examine the client cipher list in <b>ssl</b>, and determine what kind of
* client it is. Return one of CIPHERS_ERR, CIPHERS_V1, CIPHERS_V2,
* CIPHERS_UNRESTRICTED.
**/
STATIC int
tor_tls_classify_client_ciphers(const SSL *ssl,
STACK_OF(SSL_CIPHER) *peer_ciphers)
{
int i, res;
tor_tls_t *tor_tls;
if (PREDICT_UNLIKELY(!v2_cipher_list_pruned))
prune_v2_cipher_list(ssl);
tor_tls = tor_tls_get_by_ssl(ssl);
if (tor_tls && tor_tls->client_cipher_list_type)
return tor_tls->client_cipher_list_type;
/* If we reached this point, we just got a client hello. See if there is
* a cipher list. */
if (!peer_ciphers) {
log_info(LD_NET, "No ciphers on session");
res = CIPHERS_ERR;
goto done;
}
/* 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(peer_ciphers); ++i) {
const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_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)")) {
log_debug(LD_NET, "Got a non-version-1 cipher called '%s'", ciphername);
// return 1;
goto v2_or_higher;
}
}
res = CIPHERS_V1;
goto done;
v2_or_higher:
{
const uint16_t *v2_cipher = v2_cipher_list;
for (i = 0; i < sk_SSL_CIPHER_num(peer_ciphers); ++i) {
const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_ciphers, i);
uint16_t id = SSL_CIPHER_get_id(cipher) & 0xffff;
if (id == 0x00ff) /* extended renegotiation indicator. */
continue;
if (!id || id != *v2_cipher) {
res = CIPHERS_UNRESTRICTED;
goto dump_ciphers;
}
++v2_cipher;
}
if (*v2_cipher != 0) {
res = CIPHERS_UNRESTRICTED;
goto dump_ciphers;
}
res = CIPHERS_V2;
}
dump_ciphers:
{
smartlist_t *elts = smartlist_new();
char *s;
for (i = 0; i < sk_SSL_CIPHER_num(peer_ciphers); ++i) {
const SSL_CIPHER *cipher = sk_SSL_CIPHER_value(peer_ciphers, i);
const char *ciphername = SSL_CIPHER_get_name(cipher);
smartlist_add(elts, (char*)ciphername);
}
s = smartlist_join_strings(elts, ":", 0, NULL);
log_debug(LD_NET, "Got a %s V2/V3 cipher list from %s. It is: '%s'",
(res == CIPHERS_V2) ? "fictitious" : "real", ADDR(tor_tls), s);
tor_free(s);
smartlist_free(elts);
}
done:
if (tor_tls)
return tor_tls->client_cipher_list_type = res;
return res;
}
/** Return true iff the cipher list suggested by the client for <b>ssl</b> is
* a list that indicates that the client knows how to do the v2 TLS connection
* handshake. */
STATIC int
tor_tls_client_is_using_v2_ciphers(const SSL *ssl)
{
STACK_OF(SSL_CIPHER) *ciphers;
#ifdef HAVE_SSL_GET_CLIENT_CIPHERS
ciphers = SSL_get_client_ciphers(ssl);
#else
SSL_SESSION *session;
if (!(session = SSL_get_session((SSL *)ssl))) {
log_info(LD_NET, "No session on TLS?");
return CIPHERS_ERR;
}
ciphers = session->ciphers;
#endif
return tor_tls_classify_client_ciphers(ssl, ciphers) >= CIPHERS_V2;
}
/** 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_BUG_ONCE(ssl == NULL) {
return; // LCOV_EXCL_LINE
}
tor_tls_debug_state_callback(ssl, type, val);
if (type != SSL_CB_ACCEPT_LOOP)
return;
OSSL_HANDSHAKE_STATE ssl_state = SSL_get_state(ssl);
if (! STATE_IS_SW_SERVER_HELLO(ssl_state))
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;
if (tls->server_handshake_count < 127) /*avoid any overflow possibility*/
++tls->server_handshake_count;
} else {
log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!");
return;
}
/* Now check the cipher list. */
if (tor_tls_client_is_using_v2_ciphers(ssl)) {
if (tls->wasV2Handshake)
return; /* We already turned this stuff off for the first handshake;
* This is a renegotiation. */
/* 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 {
/* LCOV_EXCL_START this line is not reachable */
log_warn(LD_BUG, "Couldn't look up the tls for an SSL*. How odd!");
/* LCOV_EXCL_STOP */
}
}
}
/** Callback to get invoked on a server after we've read the list of ciphers
* the client supports, but before we pick our own ciphersuite.
*
* We can't abuse an info_cb for this, since by the time one of the
* client_hello info_cbs is called, we've already picked which ciphersuite to
* use.
*
* Technically, this function is an abuse of this callback, since the point of
* a session_secret_cb is to try to set up and/or verify a shared-secret for
* authentication on the fly. But as long as we return 0, we won't actually be
* setting up a shared secret, and all will be fine.
*/
STATIC int
tor_tls_session_secret_cb(SSL *ssl, void *secret, int *secret_len,
STACK_OF(SSL_CIPHER) *peer_ciphers,
CONST_IF_OPENSSL_1_1_API SSL_CIPHER **cipher,
void *arg)
{
(void) secret;
(void) secret_len;
(void) peer_ciphers;
(void) cipher;
(void) arg;
if (tor_tls_classify_client_ciphers(ssl, peer_ciphers) ==
CIPHERS_UNRESTRICTED) {
SSL_set_cipher_list(ssl, UNRESTRICTED_SERVER_CIPHER_LIST);
}
SSL_set_session_secret_cb(ssl, NULL, NULL);
return 0;
}
static void
tor_tls_setup_session_secret_cb(tor_tls_t *tls)
{
SSL_set_session_secret_cb(tls->ssl, tor_tls_session_secret_cb, NULL);
}
/** 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_tls_context_t *context = isServer ? server_tls_context :
client_tls_context;
result->magic = TOR_TLS_MAGIC;
check_no_tls_errors();
tor_assert(context); /* make sure somebody made it first */
if (!(result->ssl = SSL_new(context->ctx))) {
tls_log_errors(NULL, LOG_WARN, LD_NET, "creating SSL object");
tor_free(result);
goto err;
}
#ifdef SSL_set_tlsext_host_name
/* Browsers use the TLS hostname extension, so we should too. */
if (!isServer) {
char *fake_hostname = crypto_random_hostname(4,25, "www.",".com");
SSL_set_tlsext_host_name(result->ssl, fake_hostname);
tor_free(fake_hostname);
}
#endif
if (!SSL_set_cipher_list(result->ssl,
isServer ? SERVER_CIPHER_LIST : CLIENT_CIPHER_LIST)) {
tls_log_errors(NULL, LOG_WARN, LD_NET, "setting ciphers");
#ifdef SSL_set_tlsext_host_name
SSL_set_tlsext_host_name(result->ssl, NULL);
#endif
SSL_free(result->ssl);
tor_free(result);
goto err;
}
result->socket = sock;
bio = BIO_new_socket(sock, BIO_NOCLOSE);
if (! bio) {
tls_log_errors(NULL, LOG_WARN, LD_NET, "opening BIO");
#ifdef SSL_set_tlsext_host_name
SSL_set_tlsext_host_name(result->ssl, NULL);
#endif
SSL_free(result->ssl);
tor_free(result);
goto err;
}
{
int set_worked =
SSL_set_ex_data(result->ssl, tor_tls_object_ex_data_index, result);
if (!set_worked) {
log_warn(LD_BUG,
"Couldn't set the tls for an SSL*; connection will fail");
}
}
SSL_set_bio(result->ssl, bio, bio);
tor_tls_context_incref(context);
result->context = context;
result->state = TOR_TLS_ST_HANDSHAKE;
result->isServer = isServer;
result->wantwrite_n = 0;
result->last_write_count = BIO_number_written(bio);
result->last_read_count = BIO_number_read(bio);
if (result->last_write_count || result->last_read_count) {
log_warn(LD_NET, "Newly created BIO has read count %lu, write count %lu",
result->last_read_count, result->last_write_count);
}
if (isServer) {
SSL_set_info_callback(result->ssl, tor_tls_server_info_callback);
} else {
SSL_set_info_callback(result->ssl, tor_tls_debug_state_callback);
}
if (isServer)
tor_tls_setup_session_secret_cb(result);
goto done;
err:
result = NULL;
done:
/* Not expected to get called. */
tls_log_errors(NULL, LOG_WARN, LD_NET, "creating tor_tls_t object");
return result;
}
/** Make future log messages about <b>tls</b> display the address
* <b>address</b>.
*/
void
tor_tls_set_logged_address(tor_tls_t *tls, const char *address)
{
tor_assert(tls);
tor_free(tls->address);
tls->address = tor_strdup(address);
}
/** 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 until <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;
if (cb) {
SSL_set_info_callback(tls->ssl, tor_tls_server_info_callback);
} else {
SSL_set_info_callback(tls->ssl, tor_tls_debug_state_callback);
}
}
/** If this version of openssl requires it, turn on renegotiation on
* <b>tls</b>.
*/
void
tor_tls_unblock_renegotiation(tor_tls_t *tls)
{
/* Yes, we know what we are doing here. No, we do not treat a renegotiation
* as authenticating any earlier-received data. */
SSL_set_options(tls->ssl,
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);
}
/** If this version of openssl supports it, turn off renegotiation on
* <b>tls</b>. (Our protocol never requires this for security, but it's nice
* to use belt-and-suspenders here.)
*/
void
tor_tls_block_renegotiation(tor_tls_t *tls)
{
#ifdef SUPPORT_UNSAFE_RENEGOTIATION_FLAG
tls->ssl->s3->flags &= ~SSL3_FLAGS_ALLOW_UNSAFE_LEGACY_RENEGOTIATION;
#else
(void) tls;
#endif
}
/** Assert that the flags that allow legacy renegotiation are still set */
void
tor_tls_assert_renegotiation_unblocked(tor_tls_t *tls)
{
#if defined(SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) && \
SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION != 0
long options = SSL_get_options(tls->ssl);
tor_assert(0 != (options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION));
#else
(void) tls;
#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)
{
if (!tls)
return;
tor_assert(tls->ssl);
{
size_t r,w;
tor_tls_get_n_raw_bytes(tls,&r,&w); /* ensure written_by_tls is updated */
}
#ifdef SSL_set_tlsext_host_name
SSL_set_tlsext_host_name(tls->ssl, NULL);
#endif
SSL_free(tls->ssl);
tls->ssl = NULL;
tls->negotiated_callback = NULL;
if (tls->context)
tor_tls_context_decref(tls->context);
tor_free(tls->address);
tls->magic = 0x99999999;
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.
*/
MOCK_IMPL(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);
tor_assert(len<INT_MAX);
r = SSL_read(tls->ssl, cp, (int)len);
if (r > 0) {
if (tls->got_renegotiate) {
/* Renegotiation happened! */
log_info(LD_NET, "Got a TLS renegotiation from %s", ADDR(tls));
if (tls->negotiated_callback)
tls->negotiated_callback(tls, tls->callback_arg);
tls->got_renegotiate = 0;
}
return r;
}
err = tor_tls_get_error(tls, r, CATCH_ZERO, "reading", LOG_DEBUG, LD_NET);
if (err == TOR_TLS_ZERORETURN_ || err == TOR_TLS_CLOSE) {
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;
}
}
/** Total number of bytes that we've used TLS to send. Used to track TLS
* overhead. */
STATIC uint64_t total_bytes_written_over_tls = 0;
/** Total number of bytes that TLS has put on the network for us. Used to
* track TLS overhead. */
STATIC uint64_t total_bytes_written_by_tls = 0;
/** 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);
tor_assert(n < INT_MAX);
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, (int)n);
err = tor_tls_get_error(tls, r, 0, "writing", LOG_INFO, LD_NET);
if (err == TOR_TLS_DONE) {
total_bytes_written_over_tls += r;
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();
OSSL_HANDSHAKE_STATE oldstate = SSL_get_state(tls->ssl);
if (tls->isServer) {
log_debug(LD_HANDSHAKE, "About to call SSL_accept on %p (%s)", tls,
SSL_state_string_long(tls->ssl));
r = SSL_accept(tls->ssl);
} else {
log_debug(LD_HANDSHAKE, "About to call SSL_connect on %p (%s)", tls,
SSL_state_string_long(tls->ssl));
r = SSL_connect(tls->ssl);
}
OSSL_HANDSHAKE_STATE newstate = SSL_get_state(tls->ssl);
if (oldstate != newstate)
log_debug(LD_HANDSHAKE, "After call, %p was in state %s",
tls, SSL_state_string_long(tls->ssl));
/* We need to call this here and not earlier, since OpenSSL has a penchant
* for clearing its flags when you say accept or connect. */
tor_tls_unblock_renegotiation(tls);
r = tor_tls_get_error(tls,r,0, "handshaking", LOG_INFO, LD_HANDSHAKE);
if (ERR_peek_error() != 0) {
tls_log_errors(tls, tls->isServer ? LOG_INFO : LOG_WARN, LD_HANDSHAKE,
"handshaking");
return TOR_TLS_ERROR_MISC;
}
if (r == TOR_TLS_DONE) {
tls->state = TOR_TLS_ST_OPEN;
return tor_tls_finish_handshake(tls);
}
return r;
}
/** Perform the final part of the intial TLS handshake on <b>tls</b>. This
* should be called for the first handshake only: it determines whether the v1
* or the v2 handshake was used, and adjusts things for the renegotiation
* handshake as appropriate.
*
* tor_tls_handshake() calls this on its own; you only need to call this if
* bufferevent is doing the handshake for you.
*/
int
tor_tls_finish_handshake(tor_tls_t *tls)
{
int r = TOR_TLS_DONE;
check_no_tls_errors();
if (tls->isServer) {
SSL_set_info_callback(tls->ssl, NULL);
SSL_set_verify(tls->ssl, SSL_VERIFY_PEER, always_accept_verify_cb);
SSL_clear_mode(tls->ssl, SSL_MODE_NO_AUTO_CHAIN);
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;
log_debug(LD_HANDSHAKE, "Completed V2 TLS handshake with client; waiting"
" for renegotiation.");
} else {
tls->wasV2Handshake = 0;
}
} else {
/* Client-side */
tls->wasV2Handshake = 1;
/* XXXX this can move, probably? -NM */
if (SSL_set_cipher_list(tls->ssl, SERVER_CIPHER_LIST) == 0) {
tls_log_errors(NULL, LOG_WARN, LD_HANDSHAKE, "re-setting ciphers");
r = TOR_TLS_ERROR_MISC;
}
}
tls_log_errors(NULL, LOG_WARN, LD_NET, "finishing the handshake");
return r;
}
/** 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);
check_no_tls_errors();
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, LD_NET);
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, LD_NET);
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_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(tls, LOG_WARN, LD_HANDSHAKE, "getting peer certificate");
if (!cert)
return 0;
X509_free(cert);
return 1;
}
/** Return the peer certificate, or NULL if there isn't one. */
MOCK_IMPL(tor_x509_cert_t *,
tor_tls_get_peer_cert,(tor_tls_t *tls))
{
X509 *cert;
cert = SSL_get_peer_certificate(tls->ssl);
tls_log_errors(tls, LOG_WARN, LD_HANDSHAKE, "getting peer certificate");
if (!cert)
return NULL;
return tor_x509_cert_new(cert);
}
/** Warn that a certificate lifetime extends through a certain range. */
static void
log_cert_lifetime(int severity, const X509 *cert, const char *problem,
time_t now)
{
BIO *bio = NULL;
BUF_MEM *buf;
char *s1=NULL, *s2=NULL;
char mytime[33];
struct tm tm;
size_t n;
if (problem)
tor_log(severity, LD_GENERAL,
"Certificate %s. Either their clock is set wrong, or your clock "
"is wrong.",
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_const(cert)))) {
tls_log_errors(NULL, LOG_WARN, LD_NET, "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_const(cert)))) {
tls_log_errors(NULL, LOG_WARN, LD_NET, "printing certificate lifetime");
goto end;
}
BIO_get_mem_ptr(bio, &buf);
s2 = tor_strndup(buf->data, buf->length);
n = strftime(mytime, 32, "%b %d %H:%M:%S %Y UTC", tor_gmtime_r(&now, &tm));
if (n > 0) {
tor_log(severity, LD_GENERAL,
"(certificate lifetime runs from %s through %s. Your time is %s.)",
s1,s2,mytime);
} else {
tor_log(severity, LD_GENERAL,
"(certificate lifetime runs from %s through %s. "
"Couldn't get your time.)",
s1, s2);
}
end:
/* Not expected to get invoked */
tls_log_errors(NULL, LOG_WARN, LD_NET, "getting certificate lifetime");
if (bio)
BIO_free(bio);
tor_free(s1);
tor_free(s2);
}
/** Helper function: try to extract a link certificate and an identity
* certificate from <b>tls</b>, and store them in *<b>cert_out</b> and
* *<b>id_cert_out</b> respectively. Log all messages at level
* <b>severity</b>.
*
* Note that a reference is added to cert_out, so it needs to be
* freed. id_cert_out doesn't. */
MOCK_IMPL(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 chain 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(int severity, tor_tls_t *tls, crypto_pk_t **identity_key)
{
X509 *cert = NULL, *id_cert = NULL;
EVP_PKEY *id_pkey = NULL;
RSA *rsa;
int r = -1;
check_no_tls_errors();
*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;
}
tls_log_errors(tls, severity, LD_HANDSHAKE, "before verifying certificate");
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(tls, severity, LD_HANDSHAKE, "verifying certificate");
goto done;
}
rsa = EVP_PKEY_get1_RSA(id_pkey);
if (!rsa)
goto done;
*identity_key = crypto_new_pk_from_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(tls, LOG_WARN, LD_HANDSHAKE, "finishing tor_tls_verify");
return r;
}
/** Check whether the certificate set on the connection <b>tls</b> is expired
* give or take <b>past_tolerance</b> seconds, or not-yet-valid give or take
* <b>future_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(int severity, tor_tls_t *tls,
time_t now,
int past_tolerance, int future_tolerance)
{
X509 *cert;
int r = -1;
if (!(cert = SSL_get_peer_certificate(tls->ssl)))
goto done;
if (check_cert_lifetime_internal(severity, cert, now,
past_tolerance, future_tolerance) < 0)
goto done;
r = 0;
done:
if (cert)
X509_free(cert);
/* Not expected to get invoked */
tls_log_errors(tls, LOG_WARN, LD_NET, "checking certificate lifetime");
return r;
}
/** Helper: check whether <b>cert</b> is expired give or take
* <b>past_tolerance</b> seconds, or not-yet-valid give or take
* <b>future_tolerance</b> seconds. (Relative to the current time
* <b>now</b>.) If it is live, return 0. If it is not live, log a message
* and return -1. */
static int
check_cert_lifetime_internal(int severity, const X509 *cert,
time_t now,
int past_tolerance, int future_tolerance)
{
time_t t;
t = now + future_tolerance;
if (X509_cmp_time(X509_get_notBefore_const(cert), &t) > 0) {
log_cert_lifetime(severity, cert, "not yet valid", now);
return -1;
}
t = now - past_tolerance;
if (X509_cmp_time(X509_get_notAfter_const(cert), &t) < 0) {
log_cert_lifetime(severity, cert, "already expired", now);
return -1;
}
return 0;
}
/** 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,
* respectively, 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)
{
BIO *wbio, *tmpbio;
unsigned long r, w;
r = BIO_number_read(SSL_get_rbio(tls->ssl));
/* We want the number of bytes actually for real written. Unfortunately,
* sometimes OpenSSL replaces the wbio on tls->ssl with a buffering bio,
* which makes the answer turn out wrong. Let's cope with that. Note
* that this approach will fail if we ever replace tls->ssl's BIOs with
* buffering bios for reasons of our own. As an alternative, we could
* save the original BIO for tls->ssl in the tor_tls_t structure, but
* that would be tempting fate. */
wbio = SSL_get_wbio(tls->ssl);
#if OPENSSL_VERSION_NUMBER >= OPENSSL_VER(1,1,0,0,5)
/* BIO structure is opaque as of OpenSSL 1.1.0-pre5-dev. Again, not
* supposed to use this form of the version macro, but the OpenSSL developers
* introduced major API changes in the pre-release stage.
*/
if (BIO_method_type(wbio) == BIO_TYPE_BUFFER &&
(tmpbio = BIO_next(wbio)) != NULL)
wbio = tmpbio;
#else
if (wbio->method == BIO_f_buffer() && (tmpbio = BIO_next(wbio)) != NULL)
wbio = tmpbio;
#endif
w = BIO_number_written(wbio);
/* 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);
if (*n_read > INT_MAX || *n_written > INT_MAX) {
log_warn(LD_BUG, "Preposterously large value in tor_tls_get_n_raw_bytes. "
"r=%lu, last_read=%lu, w=%lu, last_written=%lu",
r, tls->last_read_count, w, tls->last_write_count);
}
total_bytes_written_by_tls += *n_written;
tls->last_read_count = r;
tls->last_write_count = w;
}
/** Return a ratio of the bytes that TLS has sent to the bytes that we've told
* it to send. Used to track whether our TLS records are getting too tiny. */
MOCK_IMPL(double,
tls_get_write_overhead_ratio,(void))
{
if (total_bytes_written_over_tls == 0)
return 1.0;
return U64_TO_DBL(total_bytes_written_by_tls) /
U64_TO_DBL(total_bytes_written_over_tls);
}
/** 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_warn(LD_CRYPTO, "Unhandled OpenSSL errors found at %s:%d: ",
tor_fix_source_file(fname), line);
tls_log_errors(NULL, LOG_WARN, LD_NET, NULL);
}
/** Return true iff the initial TLS connection at <b>tls</b> did not use a v2
* TLS handshake. Output is undefined if the handshake isn't finished. */
int
tor_tls_used_v1_handshake(tor_tls_t *tls)
{
return ! tls->wasV2Handshake;
}
/** Return the number of server handshakes that we've noticed doing on
* <b>tls</b>. */
int
tor_tls_get_num_server_handshakes(tor_tls_t *tls)
{
return tls->server_handshake_count;
}
/** Return true iff the server TLS connection <b>tls</b> got the renegotiation
* request it was waiting for. */
int
tor_tls_server_got_renegotiate(tor_tls_t *tls)
{
return tls->got_renegotiate;
}
#ifndef HAVE_SSL_GET_CLIENT_RANDOM
static size_t
SSL_get_client_random(SSL *s, uint8_t *out, size_t len)
{
if (len == 0)
return SSL3_RANDOM_SIZE;
tor_assert(len == SSL3_RANDOM_SIZE);
tor_assert(s->s3);
memcpy(out, s->s3->client_random, len);
return len;
}
#endif
#ifndef HAVE_SSL_GET_SERVER_RANDOM
static size_t
SSL_get_server_random(SSL *s, uint8_t *out, size_t len)
{
if (len == 0)
return SSL3_RANDOM_SIZE;
tor_assert(len == SSL3_RANDOM_SIZE);
tor_assert(s->s3);
memcpy(out, s->s3->server_random, len);
return len;
}
#endif
#ifndef HAVE_SSL_SESSION_GET_MASTER_KEY
STATIC size_t
SSL_SESSION_get_master_key(SSL_SESSION *s, uint8_t *out, size_t len)
{
tor_assert(s);
if (len == 0)
return s->master_key_length;
tor_assert(len == (size_t)s->master_key_length);
tor_assert(out);
memcpy(out, s->master_key, len);
return len;
}
#endif
/** Set the DIGEST256_LEN buffer at <b>secrets_out</b> to the value used in
* the v3 handshake to prove that the client knows the TLS secrets for the
* connection <b>tls</b>. Return 0 on success, -1 on failure.
*/
MOCK_IMPL(int,
tor_tls_get_tlssecrets,(tor_tls_t *tls, uint8_t *secrets_out))
{
#define TLSSECRET_MAGIC "Tor V3 handshake TLS cross-certification"
uint8_t buf[128];
size_t len;
tor_assert(tls);
SSL *const ssl = tls->ssl;
SSL_SESSION *const session = SSL_get_session(ssl);
tor_assert(ssl);
tor_assert(session);
const size_t server_random_len = SSL_get_server_random(ssl, NULL, 0);
const size_t client_random_len = SSL_get_client_random(ssl, NULL, 0);
const size_t master_key_len = SSL_SESSION_get_master_key(session, NULL, 0);
tor_assert(server_random_len);
tor_assert(client_random_len);
tor_assert(master_key_len);
len = client_random_len + server_random_len + strlen(TLSSECRET_MAGIC) + 1;
tor_assert(len <= sizeof(buf));
{
size_t r = SSL_get_client_random(ssl, buf, client_random_len);
tor_assert(r == client_random_len);
}
{
size_t r = SSL_get_server_random(ssl,
buf+client_random_len,
server_random_len);
tor_assert(r == server_random_len);
}
uint8_t *master_key = tor_malloc_zero(master_key_len);
{
size_t r = SSL_SESSION_get_master_key(session, master_key, master_key_len);
tor_assert(r == master_key_len);
}
uint8_t *nextbuf = buf + client_random_len + server_random_len;
memcpy(nextbuf, TLSSECRET_MAGIC, strlen(TLSSECRET_MAGIC) + 1);
/*
The value is an HMAC, using the TLS master key as the HMAC key, of
client_random | server_random | TLSSECRET_MAGIC
*/
crypto_hmac_sha256((char*)secrets_out,
(char*)master_key,
master_key_len,
(char*)buf, len);
memwipe(buf, 0, sizeof(buf));
memwipe(master_key, 0, master_key_len);
tor_free(master_key);
return 0;
}
/** Using the RFC5705 key material exporting construction, and the
* provided <b>context</b> (<b>context_len</b> bytes long) and
* <b>label</b> (a NUL-terminated string), compute a 32-byte secret in
* <b>secrets_out</b> that only the parties to this TLS session can
* compute. Return 0 on success and -1 on failure.
*/
MOCK_IMPL(int,
tor_tls_export_key_material,(tor_tls_t *tls, uint8_t *secrets_out,
const uint8_t *context,
size_t context_len,
const char *label))
{
tor_assert(tls);
tor_assert(tls->ssl);
int r = SSL_export_keying_material(tls->ssl,
secrets_out, DIGEST256_LEN,
label, strlen(label),
context, context_len, 1);
return (r == 1) ? 0 : -1;
}
/** Examine the amount of memory used and available for buffers in <b>tls</b>.
* Set *<b>rbuf_capacity</b> to the amount of storage allocated for the read
* buffer and *<b>rbuf_bytes</b> to the amount actually used.
* Set *<b>wbuf_capacity</b> to the amount of storage allocated for the write
* buffer and *<b>wbuf_bytes</b> to the amount actually used.
*
* Return 0 on success, -1 on failure.*/
int
tor_tls_get_buffer_sizes(tor_tls_t *tls,
size_t *rbuf_capacity, size_t *rbuf_bytes,
size_t *wbuf_capacity, size_t *wbuf_bytes)
{
#if OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0)
(void)tls;
(void)rbuf_capacity;
(void)rbuf_bytes;
(void)wbuf_capacity;
(void)wbuf_bytes;
return -1;
#else
if (tls->ssl->s3->rbuf.buf)
*rbuf_capacity = tls->ssl->s3->rbuf.len;
else
*rbuf_capacity = 0;
if (tls->ssl->s3->wbuf.buf)
*wbuf_capacity = tls->ssl->s3->wbuf.len;
else
*wbuf_capacity = 0;
*rbuf_bytes = tls->ssl->s3->rbuf.left;
*wbuf_bytes = tls->ssl->s3->wbuf.left;
return 0;
#endif
}
/** Check whether the ECC group requested is supported by the current OpenSSL
* library instance. Return 1 if the group is supported, and 0 if not.
*/
int
evaluate_ecgroup_for_tls(const char *ecgroup)
{
EC_KEY *ec_key;
int nid;
int ret;
if (!ecgroup)
nid = NID_tor_default_ecdhe_group;
else if (!strcasecmp(ecgroup, "P256"))
nid = NID_X9_62_prime256v1;
else if (!strcasecmp(ecgroup, "P224"))
nid = NID_secp224r1;
else
return 0;
ec_key = EC_KEY_new_by_curve_name(nid);
ret = (ec_key != NULL);
EC_KEY_free(ec_key);
return ret;
}
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