[tor-commits] [tor/master] Refactor crypto.[ch] into smaller DH module.
nickm at torproject.org
nickm at torproject.org
Mon Jun 18 00:41:36 UTC 2018
commit f91469c16555836f91691be8adc9c29bb33dfc3f
Author: Fernando Fernandez Mancera <ffmancera at riseup.net>
Date: Tue May 8 15:51:39 2018 +0200
Refactor crypto.[ch] into smaller DH module.
Add two new files (crypto_dh.c, crypto_dh.h) as new module of crypto.[ch]. This
new module includes all functions and dependencies related to DH operations.
Those have been removed from crypto.[ch].
Follows #24658.
Signed-off-by: Fernando Fernandez Mancera <ffmancera at riseup.net>
---
src/common/crypto.c | 580 +----------------------------------------------
src/common/crypto.h | 34 ---
src/common/crypto_dh.c | 605 +++++++++++++++++++++++++++++++++++++++++++++++++
src/common/crypto_dh.h | 58 +++++
4 files changed, 665 insertions(+), 612 deletions(-)
diff --git a/src/common/crypto.c b/src/common/crypto.c
index 6518ea9cc..072fed792 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -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"
@@ -72,14 +73,6 @@ 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;
@@ -285,14 +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 */
@@ -480,560 +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.
@@ -1051,14 +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
#if OPENSSL_VERSION_NUMBER < OPENSSL_V_SERIES(1,1,0)
diff --git a/src/common/crypto.h b/src/common/crypto.h
index c77355731..3de363bdf 100644
--- a/src/common/crypto.h
+++ b/src/common/crypto.h
@@ -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) */
diff --git a/src/common/crypto_dh.c b/src/common/crypto_dh.c
new file mode 100644
index 000000000..7e5d4c78d
--- /dev/null
+++ b/src/common/crypto_dh.c
@@ -0,0 +1,605 @@
+/* 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_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. */
+BIGNUM *dh_param_p = NULL;
+/** Shared P parameter for our TLS DH key exchanges. */
+BIGNUM *dh_param_p_tls = NULL;
+/** Shared G parameter for our DH key exchanges. */
+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);
+}
+
+/** 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;
+}
+
+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;
+}
+
diff --git a/src/common/crypto_dh.h b/src/common/crypto_dh.h
new file mode 100644
index 000000000..7c78d8c90
--- /dev/null
+++ b/src/common/crypto_dh.h
@@ -0,0 +1,58 @@
+/* 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))
+
+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);
+
+/* 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) */
+
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