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Merge remote-tracking branch 'ffmancera-1/bug24658-dh_stream'
This commit is contained in:
commit
3640c63498
@ -27,6 +27,7 @@
|
||||
#include "crypto.h"
|
||||
#include "crypto_curve25519.h"
|
||||
#include "crypto_digest.h"
|
||||
#include "crypto_dh.h"
|
||||
#include "crypto_ed25519.h"
|
||||
#include "crypto_format.h"
|
||||
#include "crypto_rand.h"
|
||||
@ -72,41 +73,12 @@ ENABLE_GCC_WARNING(redundant-decls)
|
||||
|
||||
#include "keccak-tiny/keccak-tiny.h"
|
||||
|
||||
/** A structure to hold the first half (x, g^x) of a Diffie-Hellman handshake
|
||||
* while we're waiting for the second.*/
|
||||
struct crypto_dh_t {
|
||||
DH *dh; /**< The openssl DH object */
|
||||
};
|
||||
|
||||
static int tor_check_dh_key(int severity, const BIGNUM *bn);
|
||||
|
||||
/** Boolean: has OpenSSL's crypto been initialized? */
|
||||
static int crypto_early_initialized_ = 0;
|
||||
|
||||
/** Boolean: has OpenSSL's crypto been initialized? */
|
||||
static int crypto_global_initialized_ = 0;
|
||||
|
||||
/** Log all pending crypto errors at level <b>severity</b>. Use
|
||||
* <b>doing</b> to describe our current activities.
|
||||
*/
|
||||
static void
|
||||
crypto_log_errors(int severity, const char *doing)
|
||||
{
|
||||
unsigned long 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 (!lib) lib = "(null)";
|
||||
if (!func) func = "(null)";
|
||||
if (BUG(!doing)) doing = "(null)";
|
||||
tor_log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
|
||||
doing, msg, lib, func);
|
||||
}
|
||||
}
|
||||
|
||||
#ifndef DISABLE_ENGINES
|
||||
/** Log any OpenSSL engines we're using at NOTICE. */
|
||||
static void
|
||||
@ -306,14 +278,6 @@ crypto_thread_cleanup(void)
|
||||
#endif
|
||||
}
|
||||
|
||||
/** Used by tortls.c: Get the DH* from a crypto_dh_t.
|
||||
*/
|
||||
DH *
|
||||
crypto_dh_get_dh_(crypto_dh_t *dh)
|
||||
{
|
||||
return dh->dh;
|
||||
}
|
||||
|
||||
/** Allocate and return a new symmetric cipher using the provided key and iv.
|
||||
* The key is <b>bits</b> bits long; the IV is CIPHER_IV_LEN bytes. Both
|
||||
* must be provided. Key length must be 128, 192, or 256 */
|
||||
@ -501,560 +465,6 @@ crypto_cipher_decrypt_with_iv(const char *key,
|
||||
return (int)(fromlen - CIPHER_IV_LEN);
|
||||
}
|
||||
|
||||
/* DH */
|
||||
|
||||
/** Our DH 'g' parameter */
|
||||
#define DH_GENERATOR 2
|
||||
|
||||
/** Shared P parameter for our circuit-crypto DH key exchanges. */
|
||||
static BIGNUM *dh_param_p = NULL;
|
||||
/** Shared P parameter for our TLS DH key exchanges. */
|
||||
static BIGNUM *dh_param_p_tls = NULL;
|
||||
/** Shared G parameter for our DH key exchanges. */
|
||||
static BIGNUM *dh_param_g = NULL;
|
||||
|
||||
/** Validate a given set of Diffie-Hellman parameters. This is moderately
|
||||
* computationally expensive (milliseconds), so should only be called when
|
||||
* the DH parameters change. Returns 0 on success, * -1 on failure.
|
||||
*/
|
||||
static int
|
||||
crypto_validate_dh_params(const BIGNUM *p, const BIGNUM *g)
|
||||
{
|
||||
DH *dh = NULL;
|
||||
int ret = -1;
|
||||
|
||||
/* Copy into a temporary DH object, just so that DH_check() can be called. */
|
||||
if (!(dh = DH_new()))
|
||||
goto out;
|
||||
#ifdef OPENSSL_1_1_API
|
||||
BIGNUM *dh_p, *dh_g;
|
||||
if (!(dh_p = BN_dup(p)))
|
||||
goto out;
|
||||
if (!(dh_g = BN_dup(g)))
|
||||
goto out;
|
||||
if (!DH_set0_pqg(dh, dh_p, NULL, dh_g))
|
||||
goto out;
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (!(dh->p = BN_dup(p)))
|
||||
goto out;
|
||||
if (!(dh->g = BN_dup(g)))
|
||||
goto out;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
/* Perform the validation. */
|
||||
int codes = 0;
|
||||
if (!DH_check(dh, &codes))
|
||||
goto out;
|
||||
if (BN_is_word(g, DH_GENERATOR_2)) {
|
||||
/* Per https://wiki.openssl.org/index.php/Diffie-Hellman_parameters
|
||||
*
|
||||
* OpenSSL checks the prime is congruent to 11 when g = 2; while the
|
||||
* IETF's primes are congruent to 23 when g = 2.
|
||||
*/
|
||||
BN_ULONG residue = BN_mod_word(p, 24);
|
||||
if (residue == 11 || residue == 23)
|
||||
codes &= ~DH_NOT_SUITABLE_GENERATOR;
|
||||
}
|
||||
if (codes != 0) /* Specifics on why the params suck is irrelevant. */
|
||||
goto out;
|
||||
|
||||
/* Things are probably not evil. */
|
||||
ret = 0;
|
||||
|
||||
out:
|
||||
if (dh)
|
||||
DH_free(dh);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/** Set the global Diffie-Hellman generator, used for both TLS and internal
|
||||
* DH stuff.
|
||||
*/
|
||||
static void
|
||||
crypto_set_dh_generator(void)
|
||||
{
|
||||
BIGNUM *generator;
|
||||
int r;
|
||||
|
||||
if (dh_param_g)
|
||||
return;
|
||||
|
||||
generator = BN_new();
|
||||
tor_assert(generator);
|
||||
|
||||
r = BN_set_word(generator, DH_GENERATOR);
|
||||
tor_assert(r);
|
||||
|
||||
dh_param_g = generator;
|
||||
}
|
||||
|
||||
/** Set the global TLS Diffie-Hellman modulus. Use the Apache mod_ssl DH
|
||||
* modulus. */
|
||||
void
|
||||
crypto_set_tls_dh_prime(void)
|
||||
{
|
||||
BIGNUM *tls_prime = NULL;
|
||||
int r;
|
||||
|
||||
/* If the space is occupied, free the previous TLS DH prime */
|
||||
if (BUG(dh_param_p_tls)) {
|
||||
/* LCOV_EXCL_START
|
||||
*
|
||||
* We shouldn't be calling this twice.
|
||||
*/
|
||||
BN_clear_free(dh_param_p_tls);
|
||||
dh_param_p_tls = NULL;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
|
||||
tls_prime = BN_new();
|
||||
tor_assert(tls_prime);
|
||||
|
||||
/* This is the 1024-bit safe prime that Apache uses for its DH stuff; see
|
||||
* modules/ssl/ssl_engine_dh.c; Apache also uses a generator of 2 with this
|
||||
* prime.
|
||||
*/
|
||||
r = BN_hex2bn(&tls_prime,
|
||||
"D67DE440CBBBDC1936D693D34AFD0AD50C84D239A45F520BB88174CB98"
|
||||
"BCE951849F912E639C72FB13B4B4D7177E16D55AC179BA420B2A29FE324A"
|
||||
"467A635E81FF5901377BEDDCFD33168A461AAD3B72DAE8860078045B07A7"
|
||||
"DBCA7874087D1510EA9FCC9DDD330507DD62DB88AEAA747DE0F4D6E2BD68"
|
||||
"B0E7393E0F24218EB3");
|
||||
tor_assert(r);
|
||||
|
||||
tor_assert(tls_prime);
|
||||
|
||||
dh_param_p_tls = tls_prime;
|
||||
crypto_set_dh_generator();
|
||||
tor_assert(0 == crypto_validate_dh_params(dh_param_p_tls, dh_param_g));
|
||||
}
|
||||
|
||||
/** Initialize dh_param_p and dh_param_g if they are not already
|
||||
* set. */
|
||||
static void
|
||||
init_dh_param(void)
|
||||
{
|
||||
BIGNUM *circuit_dh_prime;
|
||||
int r;
|
||||
if (BUG(dh_param_p && dh_param_g))
|
||||
return; // LCOV_EXCL_LINE This function isn't supposed to be called twice.
|
||||
|
||||
circuit_dh_prime = BN_new();
|
||||
tor_assert(circuit_dh_prime);
|
||||
|
||||
/* This is from rfc2409, section 6.2. It's a safe prime, and
|
||||
supposedly it equals:
|
||||
2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }.
|
||||
*/
|
||||
r = BN_hex2bn(&circuit_dh_prime,
|
||||
"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
|
||||
"8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
|
||||
"302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"
|
||||
"A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"
|
||||
"49286651ECE65381FFFFFFFFFFFFFFFF");
|
||||
tor_assert(r);
|
||||
|
||||
/* Set the new values as the global DH parameters. */
|
||||
dh_param_p = circuit_dh_prime;
|
||||
crypto_set_dh_generator();
|
||||
tor_assert(0 == crypto_validate_dh_params(dh_param_p, dh_param_g));
|
||||
|
||||
if (!dh_param_p_tls) {
|
||||
crypto_set_tls_dh_prime();
|
||||
}
|
||||
}
|
||||
|
||||
/** Number of bits to use when choosing the x or y value in a Diffie-Hellman
|
||||
* handshake. Since we exponentiate by this value, choosing a smaller one
|
||||
* lets our handhake go faster.
|
||||
*/
|
||||
#define DH_PRIVATE_KEY_BITS 320
|
||||
|
||||
/** Allocate and return a new DH object for a key exchange. Returns NULL on
|
||||
* failure.
|
||||
*/
|
||||
crypto_dh_t *
|
||||
crypto_dh_new(int dh_type)
|
||||
{
|
||||
crypto_dh_t *res = tor_malloc_zero(sizeof(crypto_dh_t));
|
||||
|
||||
tor_assert(dh_type == DH_TYPE_CIRCUIT || dh_type == DH_TYPE_TLS ||
|
||||
dh_type == DH_TYPE_REND);
|
||||
|
||||
if (!dh_param_p)
|
||||
init_dh_param();
|
||||
|
||||
if (!(res->dh = DH_new()))
|
||||
goto err;
|
||||
|
||||
#ifdef OPENSSL_1_1_API
|
||||
BIGNUM *dh_p = NULL, *dh_g = NULL;
|
||||
|
||||
if (dh_type == DH_TYPE_TLS) {
|
||||
dh_p = BN_dup(dh_param_p_tls);
|
||||
} else {
|
||||
dh_p = BN_dup(dh_param_p);
|
||||
}
|
||||
if (!dh_p)
|
||||
goto err;
|
||||
|
||||
dh_g = BN_dup(dh_param_g);
|
||||
if (!dh_g) {
|
||||
BN_free(dh_p);
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!DH_set0_pqg(res->dh, dh_p, NULL, dh_g)) {
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!DH_set_length(res->dh, DH_PRIVATE_KEY_BITS))
|
||||
goto err;
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (dh_type == DH_TYPE_TLS) {
|
||||
if (!(res->dh->p = BN_dup(dh_param_p_tls)))
|
||||
goto err;
|
||||
} else {
|
||||
if (!(res->dh->p = BN_dup(dh_param_p)))
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!(res->dh->g = BN_dup(dh_param_g)))
|
||||
goto err;
|
||||
|
||||
res->dh->length = DH_PRIVATE_KEY_BITS;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
return res;
|
||||
|
||||
/* LCOV_EXCL_START
|
||||
* This error condition is only reached when an allocation fails */
|
||||
err:
|
||||
crypto_log_errors(LOG_WARN, "creating DH object");
|
||||
if (res->dh) DH_free(res->dh); /* frees p and g too */
|
||||
tor_free(res);
|
||||
return NULL;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
|
||||
/** Return a copy of <b>dh</b>, sharing its internal state. */
|
||||
crypto_dh_t *
|
||||
crypto_dh_dup(const crypto_dh_t *dh)
|
||||
{
|
||||
crypto_dh_t *dh_new = tor_malloc_zero(sizeof(crypto_dh_t));
|
||||
tor_assert(dh);
|
||||
tor_assert(dh->dh);
|
||||
dh_new->dh = dh->dh;
|
||||
DH_up_ref(dh->dh);
|
||||
return dh_new;
|
||||
}
|
||||
|
||||
/** Return the length of the DH key in <b>dh</b>, in bytes.
|
||||
*/
|
||||
int
|
||||
crypto_dh_get_bytes(crypto_dh_t *dh)
|
||||
{
|
||||
tor_assert(dh);
|
||||
return DH_size(dh->dh);
|
||||
}
|
||||
|
||||
/** Generate \<x,g^x\> for our part of the key exchange. Return 0 on
|
||||
* success, -1 on failure.
|
||||
*/
|
||||
int
|
||||
crypto_dh_generate_public(crypto_dh_t *dh)
|
||||
{
|
||||
#ifndef OPENSSL_1_1_API
|
||||
again:
|
||||
#endif
|
||||
if (!DH_generate_key(dh->dh)) {
|
||||
/* LCOV_EXCL_START
|
||||
* To test this we would need some way to tell openssl to break DH. */
|
||||
crypto_log_errors(LOG_WARN, "generating DH key");
|
||||
return -1;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
#ifdef OPENSSL_1_1_API
|
||||
/* OpenSSL 1.1.x doesn't appear to let you regenerate a DH key, without
|
||||
* recreating the DH object. I have no idea what sort of aliasing madness
|
||||
* can occur here, so do the check, and just bail on failure.
|
||||
*/
|
||||
const BIGNUM *pub_key, *priv_key;
|
||||
DH_get0_key(dh->dh, &pub_key, &priv_key);
|
||||
if (tor_check_dh_key(LOG_WARN, pub_key)<0) {
|
||||
log_warn(LD_CRYPTO, "Weird! Our own DH key was invalid. I guess once-in-"
|
||||
"the-universe chances really do happen. Treating as a failure.");
|
||||
return -1;
|
||||
}
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (tor_check_dh_key(LOG_WARN, dh->dh->pub_key)<0) {
|
||||
/* LCOV_EXCL_START
|
||||
* If this happens, then openssl's DH implementation is busted. */
|
||||
log_warn(LD_CRYPTO, "Weird! Our own DH key was invalid. I guess once-in-"
|
||||
"the-universe chances really do happen. Trying again.");
|
||||
/* Free and clear the keys, so OpenSSL will actually try again. */
|
||||
BN_clear_free(dh->dh->pub_key);
|
||||
BN_clear_free(dh->dh->priv_key);
|
||||
dh->dh->pub_key = dh->dh->priv_key = NULL;
|
||||
goto again;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
return 0;
|
||||
}
|
||||
|
||||
/** Generate g^x as necessary, and write the g^x for the key exchange
|
||||
* as a <b>pubkey_len</b>-byte value into <b>pubkey</b>. Return 0 on
|
||||
* success, -1 on failure. <b>pubkey_len</b> must be \>= DH_BYTES.
|
||||
*/
|
||||
int
|
||||
crypto_dh_get_public(crypto_dh_t *dh, char *pubkey, size_t pubkey_len)
|
||||
{
|
||||
int bytes;
|
||||
tor_assert(dh);
|
||||
|
||||
const BIGNUM *dh_pub;
|
||||
|
||||
#ifdef OPENSSL_1_1_API
|
||||
const BIGNUM *dh_priv;
|
||||
DH_get0_key(dh->dh, &dh_pub, &dh_priv);
|
||||
#else
|
||||
dh_pub = dh->dh->pub_key;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
if (!dh_pub) {
|
||||
if (crypto_dh_generate_public(dh)<0)
|
||||
return -1;
|
||||
else {
|
||||
#ifdef OPENSSL_1_1_API
|
||||
DH_get0_key(dh->dh, &dh_pub, &dh_priv);
|
||||
#else
|
||||
dh_pub = dh->dh->pub_key;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
tor_assert(dh_pub);
|
||||
bytes = BN_num_bytes(dh_pub);
|
||||
tor_assert(bytes >= 0);
|
||||
if (pubkey_len < (size_t)bytes) {
|
||||
log_warn(LD_CRYPTO,
|
||||
"Weird! pubkey_len (%d) was smaller than DH_BYTES (%d)",
|
||||
(int) pubkey_len, bytes);
|
||||
return -1;
|
||||
}
|
||||
|
||||
memset(pubkey, 0, pubkey_len);
|
||||
BN_bn2bin(dh_pub, (unsigned char*)(pubkey+(pubkey_len-bytes)));
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/** Check for bad Diffie-Hellman public keys (g^x). Return 0 if the key is
|
||||
* okay (in the subgroup [2,p-2]), or -1 if it's bad.
|
||||
* See http://www.cl.cam.ac.uk/ftp/users/rja14/psandqs.ps.gz for some tips.
|
||||
*/
|
||||
static int
|
||||
tor_check_dh_key(int severity, const BIGNUM *bn)
|
||||
{
|
||||
BIGNUM *x;
|
||||
char *s;
|
||||
tor_assert(bn);
|
||||
x = BN_new();
|
||||
tor_assert(x);
|
||||
if (BUG(!dh_param_p))
|
||||
init_dh_param(); //LCOV_EXCL_LINE we already checked whether we did this.
|
||||
BN_set_word(x, 1);
|
||||
if (BN_cmp(bn,x)<=0) {
|
||||
log_fn(severity, LD_CRYPTO, "DH key must be at least 2.");
|
||||
goto err;
|
||||
}
|
||||
BN_copy(x,dh_param_p);
|
||||
BN_sub_word(x, 1);
|
||||
if (BN_cmp(bn,x)>=0) {
|
||||
log_fn(severity, LD_CRYPTO, "DH key must be at most p-2.");
|
||||
goto err;
|
||||
}
|
||||
BN_clear_free(x);
|
||||
return 0;
|
||||
err:
|
||||
BN_clear_free(x);
|
||||
s = BN_bn2hex(bn);
|
||||
log_fn(severity, LD_CRYPTO, "Rejecting insecure DH key [%s]", s);
|
||||
OPENSSL_free(s);
|
||||
return -1;
|
||||
}
|
||||
|
||||
/** Given a DH key exchange object, and our peer's value of g^y (as a
|
||||
* <b>pubkey_len</b>-byte value in <b>pubkey</b>) generate
|
||||
* <b>secret_bytes_out</b> bytes of shared key material and write them
|
||||
* to <b>secret_out</b>. Return the number of bytes generated on success,
|
||||
* or -1 on failure.
|
||||
*
|
||||
* (We generate key material by computing
|
||||
* SHA1( g^xy || "\x00" ) || SHA1( g^xy || "\x01" ) || ...
|
||||
* where || is concatenation.)
|
||||
*/
|
||||
ssize_t
|
||||
crypto_dh_compute_secret(int severity, crypto_dh_t *dh,
|
||||
const char *pubkey, size_t pubkey_len,
|
||||
char *secret_out, size_t secret_bytes_out)
|
||||
{
|
||||
char *secret_tmp = NULL;
|
||||
BIGNUM *pubkey_bn = NULL;
|
||||
size_t secret_len=0, secret_tmp_len=0;
|
||||
int result=0;
|
||||
tor_assert(dh);
|
||||
tor_assert(secret_bytes_out/DIGEST_LEN <= 255);
|
||||
tor_assert(pubkey_len < INT_MAX);
|
||||
|
||||
if (!(pubkey_bn = BN_bin2bn((const unsigned char*)pubkey,
|
||||
(int)pubkey_len, NULL)))
|
||||
goto error;
|
||||
if (tor_check_dh_key(severity, pubkey_bn)<0) {
|
||||
/* Check for invalid public keys. */
|
||||
log_fn(severity, LD_CRYPTO,"Rejected invalid g^x");
|
||||
goto error;
|
||||
}
|
||||
secret_tmp_len = crypto_dh_get_bytes(dh);
|
||||
secret_tmp = tor_malloc(secret_tmp_len);
|
||||
result = DH_compute_key((unsigned char*)secret_tmp, pubkey_bn, dh->dh);
|
||||
if (result < 0) {
|
||||
log_warn(LD_CRYPTO,"DH_compute_key() failed.");
|
||||
goto error;
|
||||
}
|
||||
secret_len = result;
|
||||
if (crypto_expand_key_material_TAP((uint8_t*)secret_tmp, secret_len,
|
||||
(uint8_t*)secret_out, secret_bytes_out)<0)
|
||||
goto error;
|
||||
secret_len = secret_bytes_out;
|
||||
|
||||
goto done;
|
||||
error:
|
||||
result = -1;
|
||||
done:
|
||||
crypto_log_errors(LOG_WARN, "completing DH handshake");
|
||||
if (pubkey_bn)
|
||||
BN_clear_free(pubkey_bn);
|
||||
if (secret_tmp) {
|
||||
memwipe(secret_tmp, 0, secret_tmp_len);
|
||||
tor_free(secret_tmp);
|
||||
}
|
||||
if (result < 0)
|
||||
return result;
|
||||
else
|
||||
return secret_len;
|
||||
}
|
||||
|
||||
/** Given <b>key_in_len</b> bytes of negotiated randomness in <b>key_in</b>
|
||||
* ("K"), expand it into <b>key_out_len</b> bytes of negotiated key material in
|
||||
* <b>key_out</b> by taking the first <b>key_out_len</b> bytes of
|
||||
* H(K | [00]) | H(K | [01]) | ....
|
||||
*
|
||||
* This is the key expansion algorithm used in the "TAP" circuit extension
|
||||
* mechanism; it shouldn't be used for new protocols.
|
||||
*
|
||||
* Return 0 on success, -1 on failure.
|
||||
*/
|
||||
int
|
||||
crypto_expand_key_material_TAP(const uint8_t *key_in, size_t key_in_len,
|
||||
uint8_t *key_out, size_t key_out_len)
|
||||
{
|
||||
int i, r = -1;
|
||||
uint8_t *cp, *tmp = tor_malloc(key_in_len+1);
|
||||
uint8_t digest[DIGEST_LEN];
|
||||
|
||||
/* If we try to get more than this amount of key data, we'll repeat blocks.*/
|
||||
tor_assert(key_out_len <= DIGEST_LEN*256);
|
||||
|
||||
memcpy(tmp, key_in, key_in_len);
|
||||
for (cp = key_out, i=0; cp < key_out+key_out_len;
|
||||
++i, cp += DIGEST_LEN) {
|
||||
tmp[key_in_len] = i;
|
||||
if (crypto_digest((char*)digest, (const char *)tmp, key_in_len+1) < 0)
|
||||
goto exit;
|
||||
memcpy(cp, digest, MIN(DIGEST_LEN, key_out_len-(cp-key_out)));
|
||||
}
|
||||
|
||||
r = 0;
|
||||
exit:
|
||||
memwipe(tmp, 0, key_in_len+1);
|
||||
tor_free(tmp);
|
||||
memwipe(digest, 0, sizeof(digest));
|
||||
return r;
|
||||
}
|
||||
|
||||
/** Expand some secret key material according to RFC5869, using SHA256 as the
|
||||
* underlying hash. The <b>key_in_len</b> bytes at <b>key_in</b> are the
|
||||
* secret key material; the <b>salt_in_len</b> bytes at <b>salt_in</b> and the
|
||||
* <b>info_in_len</b> bytes in <b>info_in_len</b> are the algorithm's "salt"
|
||||
* and "info" parameters respectively. On success, write <b>key_out_len</b>
|
||||
* bytes to <b>key_out</b> and return 0. Assert on failure.
|
||||
*/
|
||||
int
|
||||
crypto_expand_key_material_rfc5869_sha256(
|
||||
const uint8_t *key_in, size_t key_in_len,
|
||||
const uint8_t *salt_in, size_t salt_in_len,
|
||||
const uint8_t *info_in, size_t info_in_len,
|
||||
uint8_t *key_out, size_t key_out_len)
|
||||
{
|
||||
uint8_t prk[DIGEST256_LEN];
|
||||
uint8_t tmp[DIGEST256_LEN + 128 + 1];
|
||||
uint8_t mac[DIGEST256_LEN];
|
||||
int i;
|
||||
uint8_t *outp;
|
||||
size_t tmp_len;
|
||||
|
||||
crypto_hmac_sha256((char*)prk,
|
||||
(const char*)salt_in, salt_in_len,
|
||||
(const char*)key_in, key_in_len);
|
||||
|
||||
/* If we try to get more than this amount of key data, we'll repeat blocks.*/
|
||||
tor_assert(key_out_len <= DIGEST256_LEN * 256);
|
||||
tor_assert(info_in_len <= 128);
|
||||
memset(tmp, 0, sizeof(tmp));
|
||||
outp = key_out;
|
||||
i = 1;
|
||||
|
||||
while (key_out_len) {
|
||||
size_t n;
|
||||
if (i > 1) {
|
||||
memcpy(tmp, mac, DIGEST256_LEN);
|
||||
memcpy(tmp+DIGEST256_LEN, info_in, info_in_len);
|
||||
tmp[DIGEST256_LEN+info_in_len] = i;
|
||||
tmp_len = DIGEST256_LEN + info_in_len + 1;
|
||||
} else {
|
||||
memcpy(tmp, info_in, info_in_len);
|
||||
tmp[info_in_len] = i;
|
||||
tmp_len = info_in_len + 1;
|
||||
}
|
||||
crypto_hmac_sha256((char*)mac,
|
||||
(const char*)prk, DIGEST256_LEN,
|
||||
(const char*)tmp, tmp_len);
|
||||
n = key_out_len < DIGEST256_LEN ? key_out_len : DIGEST256_LEN;
|
||||
memcpy(outp, mac, n);
|
||||
key_out_len -= n;
|
||||
outp += n;
|
||||
++i;
|
||||
}
|
||||
|
||||
memwipe(tmp, 0, sizeof(tmp));
|
||||
memwipe(mac, 0, sizeof(mac));
|
||||
return 0;
|
||||
}
|
||||
|
||||
/** Free a DH key exchange object.
|
||||
*/
|
||||
void
|
||||
crypto_dh_free_(crypto_dh_t *dh)
|
||||
{
|
||||
if (!dh)
|
||||
return;
|
||||
tor_assert(dh->dh);
|
||||
DH_free(dh->dh);
|
||||
tor_free(dh);
|
||||
}
|
||||
|
||||
/** @{ */
|
||||
/** Uninitialize the crypto library. Return 0 on success. Does not detect
|
||||
* failure.
|
||||
@ -1072,14 +482,7 @@ crypto_global_cleanup(void)
|
||||
ERR_free_strings();
|
||||
#endif
|
||||
|
||||
if (dh_param_p)
|
||||
BN_clear_free(dh_param_p);
|
||||
if (dh_param_p_tls)
|
||||
BN_clear_free(dh_param_p_tls);
|
||||
if (dh_param_g)
|
||||
BN_clear_free(dh_param_g);
|
||||
|
||||
dh_param_p = dh_param_p_tls = dh_param_g = NULL;
|
||||
crypto_dh_free_all();
|
||||
|
||||
#ifndef DISABLE_ENGINES
|
||||
#ifndef OPENSSL_1_1_API
|
||||
|
@ -27,15 +27,12 @@
|
||||
#define CIPHER_IV_LEN 16
|
||||
/** Length of our symmetric cipher's keys of 256-bit. */
|
||||
#define CIPHER256_KEY_LEN 32
|
||||
/** Length of our DH keys. */
|
||||
#define DH_BYTES (1024/8)
|
||||
|
||||
/** Length of encoded public key fingerprints, including space; but not
|
||||
* including terminating NUL. */
|
||||
#define FINGERPRINT_LEN 49
|
||||
|
||||
typedef struct aes_cnt_cipher crypto_cipher_t;
|
||||
typedef struct crypto_dh_t crypto_dh_t;
|
||||
|
||||
/* global state */
|
||||
int crypto_init_siphash_key(void);
|
||||
@ -51,7 +48,6 @@ void crypto_thread_cleanup(void);
|
||||
int crypto_global_cleanup(void);
|
||||
|
||||
/* environment setup */
|
||||
void crypto_set_tls_dh_prime(void);
|
||||
crypto_cipher_t *crypto_cipher_new(const char *key);
|
||||
crypto_cipher_t *crypto_cipher_new_with_bits(const char *key, int bits);
|
||||
crypto_cipher_t *crypto_cipher_new_with_iv(const char *key, const char *iv);
|
||||
@ -78,36 +74,6 @@ int crypto_cipher_decrypt_with_iv(const char *key,
|
||||
char *to, size_t tolen,
|
||||
const char *from, size_t fromlen);
|
||||
|
||||
/* Key negotiation */
|
||||
#define DH_TYPE_CIRCUIT 1
|
||||
#define DH_TYPE_REND 2
|
||||
#define DH_TYPE_TLS 3
|
||||
crypto_dh_t *crypto_dh_new(int dh_type);
|
||||
crypto_dh_t *crypto_dh_dup(const crypto_dh_t *dh);
|
||||
int crypto_dh_get_bytes(crypto_dh_t *dh);
|
||||
int crypto_dh_generate_public(crypto_dh_t *dh);
|
||||
int crypto_dh_get_public(crypto_dh_t *dh, char *pubkey_out,
|
||||
size_t pubkey_out_len);
|
||||
ssize_t crypto_dh_compute_secret(int severity, crypto_dh_t *dh,
|
||||
const char *pubkey, size_t pubkey_len,
|
||||
char *secret_out, size_t secret_out_len);
|
||||
void crypto_dh_free_(crypto_dh_t *dh);
|
||||
#define crypto_dh_free(dh) FREE_AND_NULL(crypto_dh_t, crypto_dh_free_, (dh))
|
||||
|
||||
int crypto_expand_key_material_TAP(const uint8_t *key_in,
|
||||
size_t key_in_len,
|
||||
uint8_t *key_out, size_t key_out_len);
|
||||
int crypto_expand_key_material_rfc5869_sha256(
|
||||
const uint8_t *key_in, size_t key_in_len,
|
||||
const uint8_t *salt_in, size_t salt_in_len,
|
||||
const uint8_t *info_in, size_t info_in_len,
|
||||
uint8_t *key_out, size_t key_out_len);
|
||||
|
||||
/* Prototypes for private functions only used by tortls.c, crypto.c, and the
|
||||
* unit tests. */
|
||||
struct dh_st;
|
||||
struct dh_st *crypto_dh_get_dh_(crypto_dh_t *dh);
|
||||
|
||||
void crypto_add_spaces_to_fp(char *out, size_t outlen, const char *in);
|
||||
|
||||
#endif /* !defined(TOR_CRYPTO_H) */
|
||||
|
509
src/common/crypto_dh.c
Normal file
509
src/common/crypto_dh.c
Normal file
@ -0,0 +1,509 @@
|
||||
/* Copyright (c) 2001, Matej Pfajfar.
|
||||
* Copyright (c) 2001-2004, Roger Dingledine.
|
||||
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
|
||||
* Copyright (c) 2007-2017, The Tor Project, Inc. */
|
||||
/* See LICENSE for licensing information */
|
||||
|
||||
/**
|
||||
* \file crypto_dh.c
|
||||
* \brief Block of functions related with DH utilities and operations.
|
||||
**/
|
||||
|
||||
#include "compat_openssl.h"
|
||||
#include "crypto_dh.h"
|
||||
#include "crypto_digest.h"
|
||||
#include "crypto_hkdf.h"
|
||||
#include "crypto_util.h"
|
||||
|
||||
DISABLE_GCC_WARNING(redundant-decls)
|
||||
|
||||
#include <openssl/dh.h>
|
||||
|
||||
ENABLE_GCC_WARNING(redundant-decls)
|
||||
|
||||
#include "torlog.h"
|
||||
|
||||
/** A structure to hold the first half (x, g^x) of a Diffie-Hellman handshake
|
||||
* while we're waiting for the second.*/
|
||||
struct crypto_dh_t {
|
||||
DH *dh; /**< The openssl DH object */
|
||||
};
|
||||
|
||||
static int tor_check_dh_key(int severity, const BIGNUM *bn);
|
||||
|
||||
/** Used by tortls.c: Get the DH* from a crypto_dh_t.
|
||||
*/
|
||||
DH *
|
||||
crypto_dh_get_dh_(crypto_dh_t *dh)
|
||||
{
|
||||
return dh->dh;
|
||||
}
|
||||
|
||||
/** Our DH 'g' parameter */
|
||||
#define DH_GENERATOR 2
|
||||
|
||||
/** Shared P parameter for our circuit-crypto DH key exchanges. */
|
||||
static BIGNUM *dh_param_p = NULL;
|
||||
/** Shared P parameter for our TLS DH key exchanges. */
|
||||
static BIGNUM *dh_param_p_tls = NULL;
|
||||
/** Shared G parameter for our DH key exchanges. */
|
||||
static BIGNUM *dh_param_g = NULL;
|
||||
|
||||
/** Validate a given set of Diffie-Hellman parameters. This is moderately
|
||||
* computationally expensive (milliseconds), so should only be called when
|
||||
* the DH parameters change. Returns 0 on success, * -1 on failure.
|
||||
*/
|
||||
static int
|
||||
crypto_validate_dh_params(const BIGNUM *p, const BIGNUM *g)
|
||||
{
|
||||
DH *dh = NULL;
|
||||
int ret = -1;
|
||||
|
||||
/* Copy into a temporary DH object, just so that DH_check() can be called. */
|
||||
if (!(dh = DH_new()))
|
||||
goto out;
|
||||
#ifdef OPENSSL_1_1_API
|
||||
BIGNUM *dh_p, *dh_g;
|
||||
if (!(dh_p = BN_dup(p)))
|
||||
goto out;
|
||||
if (!(dh_g = BN_dup(g)))
|
||||
goto out;
|
||||
if (!DH_set0_pqg(dh, dh_p, NULL, dh_g))
|
||||
goto out;
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (!(dh->p = BN_dup(p)))
|
||||
goto out;
|
||||
if (!(dh->g = BN_dup(g)))
|
||||
goto out;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
/* Perform the validation. */
|
||||
int codes = 0;
|
||||
if (!DH_check(dh, &codes))
|
||||
goto out;
|
||||
if (BN_is_word(g, DH_GENERATOR_2)) {
|
||||
/* Per https://wiki.openssl.org/index.php/Diffie-Hellman_parameters
|
||||
*
|
||||
* OpenSSL checks the prime is congruent to 11 when g = 2; while the
|
||||
* IETF's primes are congruent to 23 when g = 2.
|
||||
*/
|
||||
BN_ULONG residue = BN_mod_word(p, 24);
|
||||
if (residue == 11 || residue == 23)
|
||||
codes &= ~DH_NOT_SUITABLE_GENERATOR;
|
||||
}
|
||||
if (codes != 0) /* Specifics on why the params suck is irrelevant. */
|
||||
goto out;
|
||||
|
||||
/* Things are probably not evil. */
|
||||
ret = 0;
|
||||
|
||||
out:
|
||||
if (dh)
|
||||
DH_free(dh);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/** Set the global Diffie-Hellman generator, used for both TLS and internal
|
||||
* DH stuff.
|
||||
*/
|
||||
static void
|
||||
crypto_set_dh_generator(void)
|
||||
{
|
||||
BIGNUM *generator;
|
||||
int r;
|
||||
|
||||
if (dh_param_g)
|
||||
return;
|
||||
|
||||
generator = BN_new();
|
||||
tor_assert(generator);
|
||||
|
||||
r = BN_set_word(generator, DH_GENERATOR);
|
||||
tor_assert(r);
|
||||
|
||||
dh_param_g = generator;
|
||||
}
|
||||
|
||||
/** Set the global TLS Diffie-Hellman modulus. Use the Apache mod_ssl DH
|
||||
* modulus. */
|
||||
void
|
||||
crypto_set_tls_dh_prime(void)
|
||||
{
|
||||
BIGNUM *tls_prime = NULL;
|
||||
int r;
|
||||
|
||||
/* If the space is occupied, free the previous TLS DH prime */
|
||||
if (BUG(dh_param_p_tls)) {
|
||||
/* LCOV_EXCL_START
|
||||
*
|
||||
* We shouldn't be calling this twice.
|
||||
*/
|
||||
BN_clear_free(dh_param_p_tls);
|
||||
dh_param_p_tls = NULL;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
|
||||
tls_prime = BN_new();
|
||||
tor_assert(tls_prime);
|
||||
|
||||
/* This is the 1024-bit safe prime that Apache uses for its DH stuff; see
|
||||
* modules/ssl/ssl_engine_dh.c; Apache also uses a generator of 2 with this
|
||||
* prime.
|
||||
*/
|
||||
r = BN_hex2bn(&tls_prime,
|
||||
"D67DE440CBBBDC1936D693D34AFD0AD50C84D239A45F520BB88174CB98"
|
||||
"BCE951849F912E639C72FB13B4B4D7177E16D55AC179BA420B2A29FE324A"
|
||||
"467A635E81FF5901377BEDDCFD33168A461AAD3B72DAE8860078045B07A7"
|
||||
"DBCA7874087D1510EA9FCC9DDD330507DD62DB88AEAA747DE0F4D6E2BD68"
|
||||
"B0E7393E0F24218EB3");
|
||||
tor_assert(r);
|
||||
|
||||
tor_assert(tls_prime);
|
||||
|
||||
dh_param_p_tls = tls_prime;
|
||||
crypto_set_dh_generator();
|
||||
tor_assert(0 == crypto_validate_dh_params(dh_param_p_tls, dh_param_g));
|
||||
}
|
||||
|
||||
/** Initialize dh_param_p and dh_param_g if they are not already
|
||||
* set. */
|
||||
static void
|
||||
init_dh_param(void)
|
||||
{
|
||||
BIGNUM *circuit_dh_prime;
|
||||
int r;
|
||||
if (BUG(dh_param_p && dh_param_g))
|
||||
return; // LCOV_EXCL_LINE This function isn't supposed to be called twice.
|
||||
|
||||
circuit_dh_prime = BN_new();
|
||||
tor_assert(circuit_dh_prime);
|
||||
|
||||
/* This is from rfc2409, section 6.2. It's a safe prime, and
|
||||
supposedly it equals:
|
||||
2^1024 - 2^960 - 1 + 2^64 * { [2^894 pi] + 129093 }.
|
||||
*/
|
||||
r = BN_hex2bn(&circuit_dh_prime,
|
||||
"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
|
||||
"8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
|
||||
"302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9"
|
||||
"A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE6"
|
||||
"49286651ECE65381FFFFFFFFFFFFFFFF");
|
||||
tor_assert(r);
|
||||
|
||||
/* Set the new values as the global DH parameters. */
|
||||
dh_param_p = circuit_dh_prime;
|
||||
crypto_set_dh_generator();
|
||||
tor_assert(0 == crypto_validate_dh_params(dh_param_p, dh_param_g));
|
||||
|
||||
if (!dh_param_p_tls) {
|
||||
crypto_set_tls_dh_prime();
|
||||
}
|
||||
}
|
||||
|
||||
/** Number of bits to use when choosing the x or y value in a Diffie-Hellman
|
||||
* handshake. Since we exponentiate by this value, choosing a smaller one
|
||||
* lets our handhake go faster.
|
||||
*/
|
||||
#define DH_PRIVATE_KEY_BITS 320
|
||||
|
||||
/** Allocate and return a new DH object for a key exchange. Returns NULL on
|
||||
* failure.
|
||||
*/
|
||||
crypto_dh_t *
|
||||
crypto_dh_new(int dh_type)
|
||||
{
|
||||
crypto_dh_t *res = tor_malloc_zero(sizeof(crypto_dh_t));
|
||||
|
||||
tor_assert(dh_type == DH_TYPE_CIRCUIT || dh_type == DH_TYPE_TLS ||
|
||||
dh_type == DH_TYPE_REND);
|
||||
|
||||
if (!dh_param_p)
|
||||
init_dh_param();
|
||||
|
||||
if (!(res->dh = DH_new()))
|
||||
goto err;
|
||||
|
||||
#ifdef OPENSSL_1_1_API
|
||||
BIGNUM *dh_p = NULL, *dh_g = NULL;
|
||||
|
||||
if (dh_type == DH_TYPE_TLS) {
|
||||
dh_p = BN_dup(dh_param_p_tls);
|
||||
} else {
|
||||
dh_p = BN_dup(dh_param_p);
|
||||
}
|
||||
if (!dh_p)
|
||||
goto err;
|
||||
|
||||
dh_g = BN_dup(dh_param_g);
|
||||
if (!dh_g) {
|
||||
BN_free(dh_p);
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!DH_set0_pqg(res->dh, dh_p, NULL, dh_g)) {
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!DH_set_length(res->dh, DH_PRIVATE_KEY_BITS))
|
||||
goto err;
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (dh_type == DH_TYPE_TLS) {
|
||||
if (!(res->dh->p = BN_dup(dh_param_p_tls)))
|
||||
goto err;
|
||||
} else {
|
||||
if (!(res->dh->p = BN_dup(dh_param_p)))
|
||||
goto err;
|
||||
}
|
||||
|
||||
if (!(res->dh->g = BN_dup(dh_param_g)))
|
||||
goto err;
|
||||
|
||||
res->dh->length = DH_PRIVATE_KEY_BITS;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
return res;
|
||||
|
||||
/* LCOV_EXCL_START
|
||||
* This error condition is only reached when an allocation fails */
|
||||
err:
|
||||
crypto_log_errors(LOG_WARN, "creating DH object");
|
||||
if (res->dh) DH_free(res->dh); /* frees p and g too */
|
||||
tor_free(res);
|
||||
return NULL;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
|
||||
/** Return a copy of <b>dh</b>, sharing its internal state. */
|
||||
crypto_dh_t *
|
||||
crypto_dh_dup(const crypto_dh_t *dh)
|
||||
{
|
||||
crypto_dh_t *dh_new = tor_malloc_zero(sizeof(crypto_dh_t));
|
||||
tor_assert(dh);
|
||||
tor_assert(dh->dh);
|
||||
dh_new->dh = dh->dh;
|
||||
DH_up_ref(dh->dh);
|
||||
return dh_new;
|
||||
}
|
||||
|
||||
/** Return the length of the DH key in <b>dh</b>, in bytes.
|
||||
*/
|
||||
int
|
||||
crypto_dh_get_bytes(crypto_dh_t *dh)
|
||||
{
|
||||
tor_assert(dh);
|
||||
return DH_size(dh->dh);
|
||||
}
|
||||
|
||||
/** Generate \<x,g^x\> for our part of the key exchange. Return 0 on
|
||||
* success, -1 on failure.
|
||||
*/
|
||||
int
|
||||
crypto_dh_generate_public(crypto_dh_t *dh)
|
||||
{
|
||||
#ifndef OPENSSL_1_1_API
|
||||
again:
|
||||
#endif
|
||||
if (!DH_generate_key(dh->dh)) {
|
||||
/* LCOV_EXCL_START
|
||||
* To test this we would need some way to tell openssl to break DH. */
|
||||
crypto_log_errors(LOG_WARN, "generating DH key");
|
||||
return -1;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
#ifdef OPENSSL_1_1_API
|
||||
/* OpenSSL 1.1.x doesn't appear to let you regenerate a DH key, without
|
||||
* recreating the DH object. I have no idea what sort of aliasing madness
|
||||
* can occur here, so do the check, and just bail on failure.
|
||||
*/
|
||||
const BIGNUM *pub_key, *priv_key;
|
||||
DH_get0_key(dh->dh, &pub_key, &priv_key);
|
||||
if (tor_check_dh_key(LOG_WARN, pub_key)<0) {
|
||||
log_warn(LD_CRYPTO, "Weird! Our own DH key was invalid. I guess once-in-"
|
||||
"the-universe chances really do happen. Treating as a failure.");
|
||||
return -1;
|
||||
}
|
||||
#else /* !(defined(OPENSSL_1_1_API)) */
|
||||
if (tor_check_dh_key(LOG_WARN, dh->dh->pub_key)<0) {
|
||||
/* LCOV_EXCL_START
|
||||
* If this happens, then openssl's DH implementation is busted. */
|
||||
log_warn(LD_CRYPTO, "Weird! Our own DH key was invalid. I guess once-in-"
|
||||
"the-universe chances really do happen. Trying again.");
|
||||
/* Free and clear the keys, so OpenSSL will actually try again. */
|
||||
BN_clear_free(dh->dh->pub_key);
|
||||
BN_clear_free(dh->dh->priv_key);
|
||||
dh->dh->pub_key = dh->dh->priv_key = NULL;
|
||||
goto again;
|
||||
/* LCOV_EXCL_STOP */
|
||||
}
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
return 0;
|
||||
}
|
||||
|
||||
/** Generate g^x as necessary, and write the g^x for the key exchange
|
||||
* as a <b>pubkey_len</b>-byte value into <b>pubkey</b>. Return 0 on
|
||||
* success, -1 on failure. <b>pubkey_len</b> must be \>= DH_BYTES.
|
||||
*/
|
||||
int
|
||||
crypto_dh_get_public(crypto_dh_t *dh, char *pubkey, size_t pubkey_len)
|
||||
{
|
||||
int bytes;
|
||||
tor_assert(dh);
|
||||
|
||||
const BIGNUM *dh_pub;
|
||||
|
||||
#ifdef OPENSSL_1_1_API
|
||||
const BIGNUM *dh_priv;
|
||||
DH_get0_key(dh->dh, &dh_pub, &dh_priv);
|
||||
#else
|
||||
dh_pub = dh->dh->pub_key;
|
||||
#endif /* defined(OPENSSL_1_1_API) */
|
||||
|
||||
if (!dh_pub) {
|
||||
if (crypto_dh_generate_public(dh)<0)
|
||||
return -1;
|
||||
else {
|
||||
#ifdef OPENSSL_1_1_API
|
||||
DH_get0_key(dh->dh, &dh_pub, &dh_priv);
|
||||
#else
|
||||
dh_pub = dh->dh->pub_key;
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
tor_assert(dh_pub);
|
||||
bytes = BN_num_bytes(dh_pub);
|
||||
tor_assert(bytes >= 0);
|
||||
if (pubkey_len < (size_t)bytes) {
|
||||
log_warn(LD_CRYPTO,
|
||||
"Weird! pubkey_len (%d) was smaller than DH_BYTES (%d)",
|
||||
(int) pubkey_len, bytes);
|
||||
return -1;
|
||||
}
|
||||
|
||||
memset(pubkey, 0, pubkey_len);
|
||||
BN_bn2bin(dh_pub, (unsigned char*)(pubkey+(pubkey_len-bytes)));
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/** Check for bad Diffie-Hellman public keys (g^x). Return 0 if the key is
|
||||
* okay (in the subgroup [2,p-2]), or -1 if it's bad.
|
||||
* See http://www.cl.cam.ac.uk/ftp/users/rja14/psandqs.ps.gz for some tips.
|
||||
*/
|
||||
static int
|
||||
tor_check_dh_key(int severity, const BIGNUM *bn)
|
||||
{
|
||||
BIGNUM *x;
|
||||
char *s;
|
||||
tor_assert(bn);
|
||||
x = BN_new();
|
||||
tor_assert(x);
|
||||
if (BUG(!dh_param_p))
|
||||
init_dh_param(); //LCOV_EXCL_LINE we already checked whether we did this.
|
||||
BN_set_word(x, 1);
|
||||
if (BN_cmp(bn,x)<=0) {
|
||||
log_fn(severity, LD_CRYPTO, "DH key must be at least 2.");
|
||||
goto err;
|
||||
}
|
||||
BN_copy(x,dh_param_p);
|
||||
BN_sub_word(x, 1);
|
||||
if (BN_cmp(bn,x)>=0) {
|
||||
log_fn(severity, LD_CRYPTO, "DH key must be at most p-2.");
|
||||
goto err;
|
||||
}
|
||||
BN_clear_free(x);
|
||||
return 0;
|
||||
err:
|
||||
BN_clear_free(x);
|
||||
s = BN_bn2hex(bn);
|
||||
log_fn(severity, LD_CRYPTO, "Rejecting insecure DH key [%s]", s);
|
||||
OPENSSL_free(s);
|
||||
return -1;
|
||||
}
|
||||
|
||||
/** Given a DH key exchange object, and our peer's value of g^y (as a
|
||||
* <b>pubkey_len</b>-byte value in <b>pubkey</b>) generate
|
||||
* <b>secret_bytes_out</b> bytes of shared key material and write them
|
||||
* to <b>secret_out</b>. Return the number of bytes generated on success,
|
||||
* or -1 on failure.
|
||||
*
|
||||
* (We generate key material by computing
|
||||
* SHA1( g^xy || "\x00" ) || SHA1( g^xy || "\x01" ) || ...
|
||||
* where || is concatenation.)
|
||||
*/
|
||||
ssize_t
|
||||
crypto_dh_compute_secret(int severity, crypto_dh_t *dh,
|
||||
const char *pubkey, size_t pubkey_len,
|
||||
char *secret_out, size_t secret_bytes_out)
|
||||
{
|
||||
char *secret_tmp = NULL;
|
||||
BIGNUM *pubkey_bn = NULL;
|
||||
size_t secret_len=0, secret_tmp_len=0;
|
||||
int result=0;
|
||||
tor_assert(dh);
|
||||
tor_assert(secret_bytes_out/DIGEST_LEN <= 255);
|
||||
tor_assert(pubkey_len < INT_MAX);
|
||||
|
||||
if (!(pubkey_bn = BN_bin2bn((const unsigned char*)pubkey,
|
||||
(int)pubkey_len, NULL)))
|
||||
goto error;
|
||||
if (tor_check_dh_key(severity, pubkey_bn)<0) {
|
||||
/* Check for invalid public keys. */
|
||||
log_fn(severity, LD_CRYPTO,"Rejected invalid g^x");
|
||||
goto error;
|
||||
}
|
||||
secret_tmp_len = crypto_dh_get_bytes(dh);
|
||||
secret_tmp = tor_malloc(secret_tmp_len);
|
||||
result = DH_compute_key((unsigned char*)secret_tmp, pubkey_bn, dh->dh);
|
||||
if (result < 0) {
|
||||
log_warn(LD_CRYPTO,"DH_compute_key() failed.");
|
||||
goto error;
|
||||
}
|
||||
secret_len = result;
|
||||
if (crypto_expand_key_material_TAP((uint8_t*)secret_tmp, secret_len,
|
||||
(uint8_t*)secret_out, secret_bytes_out)<0)
|
||||
goto error;
|
||||
secret_len = secret_bytes_out;
|
||||
|
||||
goto done;
|
||||
error:
|
||||
result = -1;
|
||||
done:
|
||||
crypto_log_errors(LOG_WARN, "completing DH handshake");
|
||||
if (pubkey_bn)
|
||||
BN_clear_free(pubkey_bn);
|
||||
if (secret_tmp) {
|
||||
memwipe(secret_tmp, 0, secret_tmp_len);
|
||||
tor_free(secret_tmp);
|
||||
}
|
||||
if (result < 0)
|
||||
return result;
|
||||
else
|
||||
return secret_len;
|
||||
}
|
||||
|
||||
/** Free a DH key exchange object.
|
||||
*/
|
||||
void
|
||||
crypto_dh_free_(crypto_dh_t *dh)
|
||||
{
|
||||
if (!dh)
|
||||
return;
|
||||
tor_assert(dh->dh);
|
||||
DH_free(dh->dh);
|
||||
tor_free(dh);
|
||||
}
|
||||
|
||||
void
|
||||
crypto_dh_free_all(void)
|
||||
{
|
||||
if (dh_param_p)
|
||||
BN_clear_free(dh_param_p);
|
||||
if (dh_param_p_tls)
|
||||
BN_clear_free(dh_param_p_tls);
|
||||
if (dh_param_g)
|
||||
BN_clear_free(dh_param_g);
|
||||
|
||||
dh_param_p = dh_param_p_tls = dh_param_g = NULL;
|
||||
}
|
||||
|
49
src/common/crypto_dh.h
Normal file
49
src/common/crypto_dh.h
Normal file
@ -0,0 +1,49 @@
|
||||
/* Copyright (c) 2001, Matej Pfajfar.
|
||||
* Copyright (c) 2001-2004, Roger Dingledine.
|
||||
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
|
||||
* Copyright (c) 2007-2017, The Tor Project, Inc. */
|
||||
/* See LICENSE for licensing information */
|
||||
|
||||
/**
|
||||
* \file crypto_dh.h
|
||||
*
|
||||
* \brief Headers for crypto_dh.c
|
||||
**/
|
||||
|
||||
#ifndef TOR_CRYPTO_DH_H
|
||||
#define TOR_CRYPTO_DH_H
|
||||
|
||||
#include "util.h"
|
||||
|
||||
/** Length of our DH keys. */
|
||||
#define DH_BYTES (1024/8)
|
||||
|
||||
typedef struct crypto_dh_t crypto_dh_t;
|
||||
|
||||
/* Key negotiation */
|
||||
#define DH_TYPE_CIRCUIT 1
|
||||
#define DH_TYPE_REND 2
|
||||
#define DH_TYPE_TLS 3
|
||||
void crypto_set_tls_dh_prime(void);
|
||||
crypto_dh_t *crypto_dh_new(int dh_type);
|
||||
crypto_dh_t *crypto_dh_dup(const crypto_dh_t *dh);
|
||||
int crypto_dh_get_bytes(crypto_dh_t *dh);
|
||||
int crypto_dh_generate_public(crypto_dh_t *dh);
|
||||
int crypto_dh_get_public(crypto_dh_t *dh, char *pubkey_out,
|
||||
size_t pubkey_out_len);
|
||||
ssize_t crypto_dh_compute_secret(int severity, crypto_dh_t *dh,
|
||||
const char *pubkey, size_t pubkey_len,
|
||||
char *secret_out, size_t secret_out_len);
|
||||
void crypto_dh_free_(crypto_dh_t *dh);
|
||||
#define crypto_dh_free(dh) FREE_AND_NULL(crypto_dh_t, crypto_dh_free_, (dh))
|
||||
|
||||
/* Crypto DH free */
|
||||
void crypto_dh_free_all(void);
|
||||
|
||||
/* Prototypes for private functions only used by tortls.c, crypto.c, and the
|
||||
* unit tests. */
|
||||
struct dh_st;
|
||||
struct dh_st *crypto_dh_get_dh_(crypto_dh_t *dh);
|
||||
|
||||
#endif /* !defined(TOR_CRYPTO_DH_H) */
|
||||
|
112
src/common/crypto_hkdf.c
Normal file
112
src/common/crypto_hkdf.c
Normal file
@ -0,0 +1,112 @@
|
||||
/* Copyright (c) 2001, Matej Pfajfar.
|
||||
* Copyright (c) 2001-2004, Roger Dingledine.
|
||||
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
|
||||
* Copyright (c) 2007-2017, The Tor Project, Inc. */
|
||||
/* See LICENSE for licensing information */
|
||||
|
||||
/**
|
||||
* \file crypto_hkdf.c
|
||||
* \brief Block of functions related with HKDF utilities and operations.
|
||||
**/
|
||||
|
||||
#include "crypto_hkdf.h"
|
||||
#include "crypto_util.h"
|
||||
#include "crypto_digest.h"
|
||||
|
||||
/** Given <b>key_in_len</b> bytes of negotiated randomness in <b>key_in</b>
|
||||
* ("K"), expand it into <b>key_out_len</b> bytes of negotiated key material in
|
||||
* <b>key_out</b> by taking the first <b>key_out_len</b> bytes of
|
||||
* H(K | [00]) | H(K | [01]) | ....
|
||||
*
|
||||
* This is the key expansion algorithm used in the "TAP" circuit extension
|
||||
* mechanism; it shouldn't be used for new protocols.
|
||||
*
|
||||
* Return 0 on success, -1 on failure.
|
||||
*/
|
||||
int
|
||||
crypto_expand_key_material_TAP(const uint8_t *key_in, size_t key_in_len,
|
||||
uint8_t *key_out, size_t key_out_len)
|
||||
{
|
||||
int i, r = -1;
|
||||
uint8_t *cp, *tmp = tor_malloc(key_in_len+1);
|
||||
uint8_t digest[DIGEST_LEN];
|
||||
|
||||
/* If we try to get more than this amount of key data, we'll repeat blocks.*/
|
||||
tor_assert(key_out_len <= DIGEST_LEN*256);
|
||||
|
||||
memcpy(tmp, key_in, key_in_len);
|
||||
for (cp = key_out, i=0; cp < key_out+key_out_len;
|
||||
++i, cp += DIGEST_LEN) {
|
||||
tmp[key_in_len] = i;
|
||||
if (crypto_digest((char*)digest, (const char *)tmp, key_in_len+1) < 0)
|
||||
goto exit;
|
||||
memcpy(cp, digest, MIN(DIGEST_LEN, key_out_len-(cp-key_out)));
|
||||
}
|
||||
|
||||
r = 0;
|
||||
exit:
|
||||
memwipe(tmp, 0, key_in_len+1);
|
||||
tor_free(tmp);
|
||||
memwipe(digest, 0, sizeof(digest));
|
||||
return r;
|
||||
}
|
||||
|
||||
/** Expand some secret key material according to RFC5869, using SHA256 as the
|
||||
* underlying hash. The <b>key_in_len</b> bytes at <b>key_in</b> are the
|
||||
* secret key material; the <b>salt_in_len</b> bytes at <b>salt_in</b> and the
|
||||
* <b>info_in_len</b> bytes in <b>info_in_len</b> are the algorithm's "salt"
|
||||
* and "info" parameters respectively. On success, write <b>key_out_len</b>
|
||||
* bytes to <b>key_out</b> and return 0. Assert on failure.
|
||||
*/
|
||||
int
|
||||
crypto_expand_key_material_rfc5869_sha256(
|
||||
const uint8_t *key_in, size_t key_in_len,
|
||||
const uint8_t *salt_in, size_t salt_in_len,
|
||||
const uint8_t *info_in, size_t info_in_len,
|
||||
uint8_t *key_out, size_t key_out_len)
|
||||
{
|
||||
uint8_t prk[DIGEST256_LEN];
|
||||
uint8_t tmp[DIGEST256_LEN + 128 + 1];
|
||||
uint8_t mac[DIGEST256_LEN];
|
||||
int i;
|
||||
uint8_t *outp;
|
||||
size_t tmp_len;
|
||||
|
||||
crypto_hmac_sha256((char*)prk,
|
||||
(const char*)salt_in, salt_in_len,
|
||||
(const char*)key_in, key_in_len);
|
||||
|
||||
/* If we try to get more than this amount of key data, we'll repeat blocks.*/
|
||||
tor_assert(key_out_len <= DIGEST256_LEN * 256);
|
||||
tor_assert(info_in_len <= 128);
|
||||
memset(tmp, 0, sizeof(tmp));
|
||||
outp = key_out;
|
||||
i = 1;
|
||||
|
||||
while (key_out_len) {
|
||||
size_t n;
|
||||
if (i > 1) {
|
||||
memcpy(tmp, mac, DIGEST256_LEN);
|
||||
memcpy(tmp+DIGEST256_LEN, info_in, info_in_len);
|
||||
tmp[DIGEST256_LEN+info_in_len] = i;
|
||||
tmp_len = DIGEST256_LEN + info_in_len + 1;
|
||||
} else {
|
||||
memcpy(tmp, info_in, info_in_len);
|
||||
tmp[info_in_len] = i;
|
||||
tmp_len = info_in_len + 1;
|
||||
}
|
||||
crypto_hmac_sha256((char*)mac,
|
||||
(const char*)prk, DIGEST256_LEN,
|
||||
(const char*)tmp, tmp_len);
|
||||
n = key_out_len < DIGEST256_LEN ? key_out_len : DIGEST256_LEN;
|
||||
memcpy(outp, mac, n);
|
||||
key_out_len -= n;
|
||||
outp += n;
|
||||
++i;
|
||||
}
|
||||
|
||||
memwipe(tmp, 0, sizeof(tmp));
|
||||
memwipe(mac, 0, sizeof(mac));
|
||||
return 0;
|
||||
}
|
||||
|
28
src/common/crypto_hkdf.h
Normal file
28
src/common/crypto_hkdf.h
Normal file
@ -0,0 +1,28 @@
|
||||
/* Copyright (c) 2001, Matej Pfajfar.
|
||||
* Copyright (c) 2001-2004, Roger Dingledine.
|
||||
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
|
||||
* Copyright (c) 2007-2017, The Tor Project, Inc. */
|
||||
/* See LICENSE for licensing information */
|
||||
|
||||
/**
|
||||
* \file crypto_hkdf.h
|
||||
*
|
||||
* \brief Headers for crypto_hkdf.h
|
||||
**/
|
||||
|
||||
#ifndef TOR_CRYPTO_HKDF_H
|
||||
#define TOR_CRYPTO_HKDF_H
|
||||
|
||||
#include "util.h"
|
||||
|
||||
int crypto_expand_key_material_TAP(const uint8_t *key_in,
|
||||
size_t key_in_len,
|
||||
uint8_t *key_out, size_t key_out_len);
|
||||
int crypto_expand_key_material_rfc5869_sha256(
|
||||
const uint8_t *key_in, size_t key_in_len,
|
||||
const uint8_t *salt_in, size_t salt_in_len,
|
||||
const uint8_t *info_in, size_t info_in_len,
|
||||
uint8_t *key_out, size_t key_out_len);
|
||||
|
||||
#endif /* !defined(TOR_CRYPTO_HKDF_H) */
|
||||
|
@ -44,27 +44,6 @@ struct crypto_pk_t
|
||||
RSA *key; /**< The key itself */
|
||||
};
|
||||
|
||||
/** Log all pending crypto errors at level <b>severity</b>. Use
|
||||
* <b>doing</b> to describe our current activities.
|
||||
*/
|
||||
static void
|
||||
crypto_log_errors(int severity, const char *doing)
|
||||
{
|
||||
unsigned long 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 (!lib) lib = "(null)";
|
||||
if (!func) func = "(null)";
|
||||
if (BUG(!doing)) doing = "(null)";
|
||||
tor_log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
|
||||
doing, msg, lib, func);
|
||||
}
|
||||
}
|
||||
|
||||
/** Return the number of bytes added by padding method <b>padding</b>.
|
||||
*/
|
||||
int
|
||||
|
@ -15,6 +15,7 @@
|
||||
#include "compat.h"
|
||||
#include "crypto.h"
|
||||
#include "crypto_digest.h"
|
||||
#include "crypto_hkdf.h"
|
||||
#include "crypto_rand.h"
|
||||
#include "crypto_s2k.h"
|
||||
#include "crypto_util.h"
|
||||
|
@ -27,10 +27,13 @@
|
||||
|
||||
DISABLE_GCC_WARNING(redundant-decls)
|
||||
|
||||
#include <openssl/err.h>
|
||||
#include <openssl/crypto.h>
|
||||
|
||||
ENABLE_GCC_WARNING(redundant-decls)
|
||||
|
||||
#include "torlog.h"
|
||||
|
||||
/**
|
||||
* Destroy the <b>sz</b> bytes of data stored at <b>mem</b>, setting them to
|
||||
* the value <b>byte</b>.
|
||||
@ -103,5 +106,25 @@ memwipe(void *mem, uint8_t byte, size_t sz)
|
||||
memset(mem, byte, sz);
|
||||
}
|
||||
|
||||
/** Log all pending crypto errors at level <b>severity</b>. Use
|
||||
* <b>doing</b> to describe our current activities.
|
||||
*/
|
||||
void
|
||||
crypto_log_errors(int severity, const char *doing)
|
||||
{
|
||||
unsigned long 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 (!lib) lib = "(null)";
|
||||
if (!func) func = "(null)";
|
||||
if (BUG(!doing)) doing = "(null)";
|
||||
tor_log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
|
||||
doing, msg, lib, func);
|
||||
}
|
||||
}
|
||||
#endif /* !defined(CRYPTO_UTIL_PRIVATE) */
|
||||
|
||||
|
@ -18,6 +18,9 @@
|
||||
/** OpenSSL-based utility functions. */
|
||||
void memwipe(void *mem, uint8_t byte, size_t sz);
|
||||
|
||||
/** Log utility function */
|
||||
void crypto_log_errors(int severity, const char *doing);
|
||||
|
||||
#ifdef CRYPTO_UTIL_PRIVATE
|
||||
#ifdef TOR_UNIT_TESTS
|
||||
#endif /* defined(TOR_UNIT_TESTS) */
|
||||
|
@ -119,8 +119,10 @@ LIBOR_CRYPTO_A_SRC = \
|
||||
src/common/compress_zlib.c \
|
||||
src/common/compress_zstd.c \
|
||||
src/common/crypto.c \
|
||||
src/common/crypto_dh.c \
|
||||
src/common/crypto_digest.c \
|
||||
src/common/crypto_format.c \
|
||||
src/common/crypto_hkdf.c \
|
||||
src/common/crypto_openssl_mgt.c \
|
||||
src/common/crypto_pwbox.c \
|
||||
src/common/crypto_rand.c \
|
||||
@ -179,10 +181,12 @@ COMMONHEADERS = \
|
||||
src/common/confline.h \
|
||||
src/common/container.h \
|
||||
src/common/crypto.h \
|
||||
src/common/crypto_dh.h \
|
||||
src/common/crypto_digest.h \
|
||||
src/common/crypto_curve25519.h \
|
||||
src/common/crypto_ed25519.h \
|
||||
src/common/crypto_format.h \
|
||||
src/common/crypto_hkdf.h \
|
||||
src/common/crypto_openssl_mgt.h \
|
||||
src/common/crypto_pwbox.h \
|
||||
src/common/crypto_rand.h \
|
||||
|
@ -27,6 +27,7 @@
|
||||
|
||||
#include "crypto.h"
|
||||
#include "crypto_rand.h"
|
||||
#include "crypto_dh.h"
|
||||
#include "crypto_util.h"
|
||||
#include "compat.h"
|
||||
|
||||
|
@ -22,6 +22,7 @@
|
||||
|
||||
#define ONION_NTOR_PRIVATE
|
||||
#include "crypto.h"
|
||||
#include "crypto_hkdf.h"
|
||||
#include "crypto_digest.h"
|
||||
#include "crypto_util.h"
|
||||
#include "onion_ntor.h"
|
||||
|
@ -68,6 +68,8 @@
|
||||
|
||||
#include "crypto.h"
|
||||
#include "crypto_format.h"
|
||||
#include "crypto_dh.h"
|
||||
#include "crypto_hkdf.h"
|
||||
#include "tortls.h"
|
||||
#include "torlog.h"
|
||||
#include "container.h"
|
||||
|
@ -78,29 +78,6 @@ show_help(void)
|
||||
"[--passphrase-fd <fd>]\n");
|
||||
}
|
||||
|
||||
/* XXXX copied from crypto.c */
|
||||
static void
|
||||
crypto_log_errors(int severity, const char *doing)
|
||||
{
|
||||
unsigned long 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 (!lib) lib = "(null)";
|
||||
if (!func) func = "(null)";
|
||||
if (doing) {
|
||||
tor_log(severity, LD_CRYPTO, "crypto error while %s: %s (in %s:%s)",
|
||||
doing, msg, lib, func);
|
||||
} else {
|
||||
tor_log(severity, LD_CRYPTO, "crypto error: %s (in %s:%s)",
|
||||
msg, lib, func);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/** Read the passphrase from the passphrase fd. */
|
||||
static int
|
||||
load_passphrase(void)
|
||||
|
Loading…
Reference in New Issue
Block a user