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Diffstat (limited to 'src/common/crypto.c')
| -rw-r--r-- | src/common/crypto.c | 1118 |
1 files changed, 0 insertions, 1118 deletions
diff --git a/src/common/crypto.c b/src/common/crypto.c deleted file mode 100644 index d5b7c96916..0000000000 --- a/src/common/crypto.c +++ /dev/null @@ -1,1118 +0,0 @@ -/* 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.c - * \brief Wrapper functions to present a consistent interface to - * public-key and symmetric cryptography operations from OpenSSL and - * other places. - **/ - -#include "orconfig.h" - -#ifdef _WIN32 -#include <winsock2.h> -#include <windows.h> -#include <wincrypt.h> -/* Windows defines this; so does OpenSSL 0.9.8h and later. We don't actually - * use either definition. */ -#undef OCSP_RESPONSE -#endif /* defined(_WIN32) */ - -#define CRYPTO_PRIVATE -#include "compat_openssl.h" -#include "crypto.h" -#include "crypto_curve25519.h" -#include "crypto_digest.h" -#include "crypto_ed25519.h" -#include "crypto_format.h" -#include "crypto_rand.h" -#include "crypto_rsa.h" -#include "crypto_util.h" - -DISABLE_GCC_WARNING(redundant-decls) - -#include <openssl/err.h> -#include <openssl/evp.h> -#include <openssl/engine.h> -#include <openssl/bn.h> -#include <openssl/dh.h> -#include <openssl/conf.h> -#include <openssl/hmac.h> -#include <openssl/ssl.h> - -ENABLE_GCC_WARNING(redundant-decls) - -#if __GNUC__ && GCC_VERSION >= 402 -#if GCC_VERSION >= 406 -#pragma GCC diagnostic pop -#else -#pragma GCC diagnostic warning "-Wredundant-decls" -#endif -#endif /* __GNUC__ && GCC_VERSION >= 402 */ - -#ifdef HAVE_CTYPE_H -#include <ctype.h> -#endif -#ifdef HAVE_UNISTD_H -#include <unistd.h> -#endif - -#include "torlog.h" -#include "torint.h" -#include "aes.h" -#include "util.h" -#include "container.h" -#include "compat.h" -#include "sandbox.h" -#include "util_format.h" - -#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 -log_engine(const char *fn, ENGINE *e) -{ - if (e) { - const char *name, *id; - name = ENGINE_get_name(e); - id = ENGINE_get_id(e); - log_notice(LD_CRYPTO, "Default OpenSSL engine for %s is %s [%s]", - fn, name?name:"?", id?id:"?"); - } else { - log_info(LD_CRYPTO, "Using default implementation for %s", fn); - } -} -#endif /* !defined(DISABLE_ENGINES) */ - -#ifndef DISABLE_ENGINES -/** Try to load an engine in a shared library via fully qualified path. - */ -static ENGINE * -try_load_engine(const char *path, const char *engine) -{ - ENGINE *e = ENGINE_by_id("dynamic"); - if (e) { - if (!ENGINE_ctrl_cmd_string(e, "ID", engine, 0) || - !ENGINE_ctrl_cmd_string(e, "DIR_LOAD", "2", 0) || - !ENGINE_ctrl_cmd_string(e, "DIR_ADD", path, 0) || - !ENGINE_ctrl_cmd_string(e, "LOAD", NULL, 0)) { - ENGINE_free(e); - e = NULL; - } - } - return e; -} -#endif /* !defined(DISABLE_ENGINES) */ - -static int have_seeded_siphash = 0; - -/** Set up the siphash key if we haven't already done so. */ -int -crypto_init_siphash_key(void) -{ - struct sipkey key; - if (have_seeded_siphash) - return 0; - - crypto_rand((char*) &key, sizeof(key)); - siphash_set_global_key(&key); - have_seeded_siphash = 1; - return 0; -} - -/** Initialize the crypto library. Return 0 on success, -1 on failure. - */ -int -crypto_early_init(void) -{ - if (!crypto_early_initialized_) { - - crypto_early_initialized_ = 1; - -#ifdef OPENSSL_1_1_API - OPENSSL_init_ssl(OPENSSL_INIT_LOAD_SSL_STRINGS | - OPENSSL_INIT_LOAD_CRYPTO_STRINGS | - OPENSSL_INIT_ADD_ALL_CIPHERS | - OPENSSL_INIT_ADD_ALL_DIGESTS, NULL); -#else - ERR_load_crypto_strings(); - OpenSSL_add_all_algorithms(); -#endif - - setup_openssl_threading(); - - unsigned long version_num = OpenSSL_version_num(); - const char *version_str = OpenSSL_version(OPENSSL_VERSION); - if (version_num == OPENSSL_VERSION_NUMBER && - !strcmp(version_str, OPENSSL_VERSION_TEXT)) { - log_info(LD_CRYPTO, "OpenSSL version matches version from headers " - "(%lx: %s).", version_num, version_str); - } else { - log_warn(LD_CRYPTO, "OpenSSL version from headers does not match the " - "version we're running with. If you get weird crashes, that " - "might be why. (Compiled with %lx: %s; running with %lx: %s).", - (unsigned long)OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_TEXT, - version_num, version_str); - } - - crypto_force_rand_ssleay(); - - if (crypto_seed_rng() < 0) - return -1; - if (crypto_init_siphash_key() < 0) - return -1; - - curve25519_init(); - ed25519_init(); - } - return 0; -} - -/** Initialize the crypto library. Return 0 on success, -1 on failure. - */ -int -crypto_global_init(int useAccel, const char *accelName, const char *accelDir) -{ - if (!crypto_global_initialized_) { - if (crypto_early_init() < 0) - return -1; - - crypto_global_initialized_ = 1; - - if (useAccel > 0) { -#ifdef DISABLE_ENGINES - (void)accelName; - (void)accelDir; - log_warn(LD_CRYPTO, "No OpenSSL hardware acceleration support enabled."); -#else - ENGINE *e = NULL; - - log_info(LD_CRYPTO, "Initializing OpenSSL engine support."); - ENGINE_load_builtin_engines(); - ENGINE_register_all_complete(); - - if (accelName) { - if (accelDir) { - log_info(LD_CRYPTO, "Trying to load dynamic OpenSSL engine \"%s\"" - " via path \"%s\".", accelName, accelDir); - e = try_load_engine(accelName, accelDir); - } else { - log_info(LD_CRYPTO, "Initializing dynamic OpenSSL engine \"%s\"" - " acceleration support.", accelName); - e = ENGINE_by_id(accelName); - } - if (!e) { - log_warn(LD_CRYPTO, "Unable to load dynamic OpenSSL engine \"%s\".", - accelName); - } else { - log_info(LD_CRYPTO, "Loaded dynamic OpenSSL engine \"%s\".", - accelName); - } - } - if (e) { - log_info(LD_CRYPTO, "Loaded OpenSSL hardware acceleration engine," - " setting default ciphers."); - ENGINE_set_default(e, ENGINE_METHOD_ALL); - } - /* Log, if available, the intersection of the set of algorithms - used by Tor and the set of algorithms available in the engine */ - log_engine("RSA", ENGINE_get_default_RSA()); - log_engine("DH", ENGINE_get_default_DH()); -#ifdef OPENSSL_1_1_API - log_engine("EC", ENGINE_get_default_EC()); -#else - log_engine("ECDH", ENGINE_get_default_ECDH()); - log_engine("ECDSA", ENGINE_get_default_ECDSA()); -#endif /* defined(OPENSSL_1_1_API) */ - log_engine("RAND", ENGINE_get_default_RAND()); - log_engine("RAND (which we will not use)", ENGINE_get_default_RAND()); - log_engine("SHA1", ENGINE_get_digest_engine(NID_sha1)); - log_engine("3DES-CBC", ENGINE_get_cipher_engine(NID_des_ede3_cbc)); - log_engine("AES-128-ECB", ENGINE_get_cipher_engine(NID_aes_128_ecb)); - log_engine("AES-128-CBC", ENGINE_get_cipher_engine(NID_aes_128_cbc)); -#ifdef NID_aes_128_ctr - log_engine("AES-128-CTR", ENGINE_get_cipher_engine(NID_aes_128_ctr)); -#endif -#ifdef NID_aes_128_gcm - log_engine("AES-128-GCM", ENGINE_get_cipher_engine(NID_aes_128_gcm)); -#endif - log_engine("AES-256-CBC", ENGINE_get_cipher_engine(NID_aes_256_cbc)); -#ifdef NID_aes_256_gcm - log_engine("AES-256-GCM", ENGINE_get_cipher_engine(NID_aes_256_gcm)); -#endif - -#endif /* defined(DISABLE_ENGINES) */ - } else { - log_info(LD_CRYPTO, "NOT using OpenSSL engine support."); - } - - if (crypto_force_rand_ssleay()) { - if (crypto_seed_rng() < 0) - return -1; - } - - evaluate_evp_for_aes(-1); - evaluate_ctr_for_aes(); - } - return 0; -} - -/** Free crypto resources held by this thread. */ -void -crypto_thread_cleanup(void) -{ -#ifndef NEW_THREAD_API - ERR_remove_thread_state(NULL); -#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 */ -crypto_cipher_t * -crypto_cipher_new_with_iv_and_bits(const uint8_t *key, - const uint8_t *iv, - int bits) -{ - tor_assert(key); - tor_assert(iv); - - return aes_new_cipher((const uint8_t*)key, (const uint8_t*)iv, bits); -} - -/** Allocate and return a new symmetric cipher using the provided key and iv. - * The key is CIPHER_KEY_LEN bytes; the IV is CIPHER_IV_LEN bytes. Both - * must be provided. - */ -crypto_cipher_t * -crypto_cipher_new_with_iv(const char *key, const char *iv) -{ - return crypto_cipher_new_with_iv_and_bits((uint8_t*)key, (uint8_t*)iv, - 128); -} - -/** Return a new crypto_cipher_t with the provided <b>key</b> and an IV of all - * zero bytes and key length <b>bits</b>. Key length must be 128, 192, or - * 256. */ -crypto_cipher_t * -crypto_cipher_new_with_bits(const char *key, int bits) -{ - char zeroiv[CIPHER_IV_LEN]; - memset(zeroiv, 0, sizeof(zeroiv)); - return crypto_cipher_new_with_iv_and_bits((uint8_t*)key, (uint8_t*)zeroiv, - bits); -} - -/** Return a new crypto_cipher_t with the provided <b>key</b> (of - * CIPHER_KEY_LEN bytes) and an IV of all zero bytes. */ -crypto_cipher_t * -crypto_cipher_new(const char *key) -{ - return crypto_cipher_new_with_bits(key, 128); -} - -/** Free a symmetric cipher. - */ -void -crypto_cipher_free_(crypto_cipher_t *env) -{ - if (!env) - return; - - aes_cipher_free(env); -} - -/** Copy <b>in</b> to the <b>outlen</b>-byte buffer <b>out</b>, adding spaces - * every four characters. */ -void -crypto_add_spaces_to_fp(char *out, size_t outlen, const char *in) -{ - int n = 0; - char *end = out+outlen; - tor_assert(outlen < SIZE_T_CEILING); - - while (*in && out<end) { - *out++ = *in++; - if (++n == 4 && *in && out<end) { - n = 0; - *out++ = ' '; - } - } - tor_assert(out<end); - *out = '\0'; -} - -/* symmetric crypto */ - -/** Encrypt <b>fromlen</b> bytes from <b>from</b> using the cipher - * <b>env</b>; on success, store the result to <b>to</b> and return 0. - * Does not check for failure. - */ -int -crypto_cipher_encrypt(crypto_cipher_t *env, char *to, - const char *from, size_t fromlen) -{ - tor_assert(env); - tor_assert(env); - tor_assert(from); - tor_assert(fromlen); - tor_assert(to); - tor_assert(fromlen < SIZE_T_CEILING); - - memcpy(to, from, fromlen); - aes_crypt_inplace(env, to, fromlen); - return 0; -} - -/** Decrypt <b>fromlen</b> bytes from <b>from</b> using the cipher - * <b>env</b>; on success, store the result to <b>to</b> and return 0. - * Does not check for failure. - */ -int -crypto_cipher_decrypt(crypto_cipher_t *env, char *to, - const char *from, size_t fromlen) -{ - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < SIZE_T_CEILING); - - memcpy(to, from, fromlen); - aes_crypt_inplace(env, to, fromlen); - return 0; -} - -/** Encrypt <b>len</b> bytes on <b>from</b> using the cipher in <b>env</b>; - * on success. Does not check for failure. - */ -void -crypto_cipher_crypt_inplace(crypto_cipher_t *env, char *buf, size_t len) -{ - tor_assert(len < SIZE_T_CEILING); - aes_crypt_inplace(env, buf, len); -} - -/** Encrypt <b>fromlen</b> bytes (at least 1) from <b>from</b> with the key in - * <b>key</b> to the buffer in <b>to</b> of length - * <b>tolen</b>. <b>tolen</b> must be at least <b>fromlen</b> plus - * CIPHER_IV_LEN bytes for the initialization vector. On success, return the - * number of bytes written, on failure, return -1. - */ -int -crypto_cipher_encrypt_with_iv(const char *key, - char *to, size_t tolen, - const char *from, size_t fromlen) -{ - crypto_cipher_t *cipher; - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < INT_MAX); - - if (fromlen < 1) - return -1; - if (tolen < fromlen + CIPHER_IV_LEN) - return -1; - - char iv[CIPHER_IV_LEN]; - crypto_rand(iv, sizeof(iv)); - cipher = crypto_cipher_new_with_iv(key, iv); - - memcpy(to, iv, CIPHER_IV_LEN); - crypto_cipher_encrypt(cipher, to+CIPHER_IV_LEN, from, fromlen); - crypto_cipher_free(cipher); - memwipe(iv, 0, sizeof(iv)); - return (int)(fromlen + CIPHER_IV_LEN); -} - -/** Decrypt <b>fromlen</b> bytes (at least 1+CIPHER_IV_LEN) from <b>from</b> - * with the key in <b>key</b> to the buffer in <b>to</b> of length - * <b>tolen</b>. <b>tolen</b> must be at least <b>fromlen</b> minus - * CIPHER_IV_LEN bytes for the initialization vector. On success, return the - * number of bytes written, on failure, return -1. - */ -int -crypto_cipher_decrypt_with_iv(const char *key, - char *to, size_t tolen, - const char *from, size_t fromlen) -{ - crypto_cipher_t *cipher; - tor_assert(key); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < INT_MAX); - - if (fromlen <= CIPHER_IV_LEN) - return -1; - if (tolen < fromlen - CIPHER_IV_LEN) - return -1; - - cipher = crypto_cipher_new_with_iv(key, from); - - crypto_cipher_encrypt(cipher, to, from+CIPHER_IV_LEN, fromlen-CIPHER_IV_LEN); - crypto_cipher_free(cipher); - 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. - */ -int -crypto_global_cleanup(void) -{ -#ifndef OPENSSL_1_1_API - EVP_cleanup(); -#endif -#ifndef NEW_THREAD_API - ERR_remove_thread_state(NULL); -#endif -#ifndef OPENSSL_1_1_API - 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; - -#ifndef DISABLE_ENGINES -#ifndef OPENSSL_1_1_API - ENGINE_cleanup(); -#endif -#endif - - CONF_modules_unload(1); -#ifndef OPENSSL_1_1_API - CRYPTO_cleanup_all_ex_data(); -#endif - - crypto_openssl_free_all(); - - crypto_early_initialized_ = 0; - crypto_global_initialized_ = 0; - have_seeded_siphash = 0; - siphash_unset_global_key(); - - return 0; -} - -/** @} */ - -#ifdef USE_DMALLOC -/** Tell the crypto library to use Tor's allocation functions rather than - * calling libc's allocation functions directly. Return 0 on success, -1 - * on failure. */ -int -crypto_use_tor_alloc_functions(void) -{ - int r = CRYPTO_set_mem_ex_functions(tor_malloc_, tor_realloc_, tor_free_); - return r ? 0 : -1; -} -#endif /* defined(USE_DMALLOC) */ - |