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Diffstat (limited to 'src/common/crypto.c')
| -rw-r--r-- | src/common/crypto.c | 3432 |
1 files changed, 0 insertions, 3432 deletions
diff --git a/src/common/crypto.c b/src/common/crypto.c deleted file mode 100644 index f8495bb107..0000000000 --- a/src/common/crypto.c +++ /dev/null @@ -1,3432 +0,0 @@ -/* Copyright (c) 2001, Matej Pfajfar. - * Copyright (c) 2001-2004, Roger Dingledine. - * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. - * Copyright (c) 2007-2016, 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 - -#define CRYPTO_PRIVATE -#include "crypto.h" -#include "compat_openssl.h" -#include "crypto_curve25519.h" -#include "crypto_ed25519.h" -#include "crypto_format.h" - -DISABLE_GCC_WARNING(redundant-decls) - -#include <openssl/err.h> -#include <openssl/rsa.h> -#include <openssl/pem.h> -#include <openssl/evp.h> -#include <openssl/engine.h> -#include <openssl/rand.h> -#include <openssl/bn.h> -#include <openssl/dh.h> -#include <openssl/conf.h> -#include <openssl/hmac.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 - -#ifdef HAVE_CTYPE_H -#include <ctype.h> -#endif -#ifdef HAVE_UNISTD_H -#include <unistd.h> -#endif -#ifdef HAVE_FCNTL_H -#include <fcntl.h> -#endif -#ifdef HAVE_SYS_FCNTL_H -#include <sys/fcntl.h> -#endif -#ifdef HAVE_SYS_SYSCALL_H -#include <sys/syscall.h> -#endif -#ifdef HAVE_SYS_RANDOM_H -#include <sys/random.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" - -#ifdef ANDROID -/* Android's OpenSSL seems to have removed all of its Engine support. */ -#define DISABLE_ENGINES -#endif - -#if OPENSSL_VERSION_NUMBER >= OPENSSL_VER(1,1,0,0,5) && \ - !defined(LIBRESSL_VERSION_NUMBER) -/* OpenSSL as of 1.1.0pre4 has an "new" thread API, which doesn't require - * seting up various callbacks. - * - * OpenSSL 1.1.0pre4 has a messed up `ERR_remove_thread_state()` prototype, - * while the previous one was restored in pre5, and the function made a no-op - * (along with a deprecated annotation, which produces a compiler warning). - * - * While it is possible to support all three versions of the thread API, - * a version that existed only for one snapshot pre-release is kind of - * pointless, so let's not. - */ -#define NEW_THREAD_API -#endif - -/** Longest recognized */ -#define MAX_DNS_LABEL_SIZE 63 - -/** Largest strong entropy request */ -#define MAX_STRONGEST_RAND_SIZE 256 - -#ifndef NEW_THREAD_API -/** A number of preallocated mutexes for use by OpenSSL. */ -static tor_mutex_t **openssl_mutexes_ = NULL; -/** How many mutexes have we allocated for use by OpenSSL? */ -static int n_openssl_mutexes_ = 0; -#endif - -/** A public key, or a public/private key-pair. */ -struct crypto_pk_t -{ - int refs; /**< reference count, so we don't have to copy keys */ - RSA *key; /**< The key itself */ -}; - -/** 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 setup_openssl_threading(void); -static int tor_check_dh_key(int severity, const BIGNUM *bn); - -/** Return the number of bytes added by padding method <b>padding</b>. - */ -static inline int -crypto_get_rsa_padding_overhead(int padding) -{ - switch (padding) - { - case RSA_PKCS1_OAEP_PADDING: return PKCS1_OAEP_PADDING_OVERHEAD; - default: tor_assert(0); return -1; // LCOV_EXCL_LINE - } -} - -/** Given a padding method <b>padding</b>, return the correct OpenSSL constant. - */ -static inline int -crypto_get_rsa_padding(int padding) -{ - switch (padding) - { - case PK_PKCS1_OAEP_PADDING: return RSA_PKCS1_OAEP_PADDING; - default: tor_assert(0); return -1; // LCOV_EXCL_LINE - } -} - -/** 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 - -#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 - -/* Returns a trimmed and human-readable version of an openssl version string -* <b>raw_version</b>. They are usually in the form of 'OpenSSL 1.0.0b 10 -* May 2012' and this will parse them into a form similar to '1.0.0b' */ -static char * -parse_openssl_version_str(const char *raw_version) -{ - const char *end_of_version = NULL; - /* The output should be something like "OpenSSL 1.0.0b 10 May 2012. Let's - trim that down. */ - if (!strcmpstart(raw_version, "OpenSSL ")) { - raw_version += strlen("OpenSSL "); - end_of_version = strchr(raw_version, ' '); - } - - if (end_of_version) - return tor_strndup(raw_version, - end_of_version-raw_version); - else - return tor_strdup(raw_version); -} - -static char *crypto_openssl_version_str = NULL; -/* Return a human-readable version of the run-time openssl version number. */ -const char * -crypto_openssl_get_version_str(void) -{ - if (crypto_openssl_version_str == NULL) { - const char *raw_version = OpenSSL_version(OPENSSL_VERSION); - crypto_openssl_version_str = parse_openssl_version_str(raw_version); - } - return crypto_openssl_version_str; -} - -static char *crypto_openssl_header_version_str = NULL; -/* Return a human-readable version of the compile-time openssl version -* number. */ -const char * -crypto_openssl_get_header_version_str(void) -{ - if (crypto_openssl_header_version_str == NULL) { - crypto_openssl_header_version_str = - parse_openssl_version_str(OPENSSL_VERSION_TEXT); - } - return crypto_openssl_header_version_str; -} - -/** Make sure that openssl is using its default PRNG. Return 1 if we had to - * adjust it; 0 otherwise. */ -STATIC int -crypto_force_rand_ssleay(void) -{ - RAND_METHOD *default_method; - default_method = RAND_OpenSSL(); - if (RAND_get_rand_method() != default_method) { - log_notice(LD_CRYPTO, "It appears that one of our engines has provided " - "a replacement the OpenSSL RNG. Resetting it to the default " - "implementation."); - RAND_set_rand_method(default_method); - return 1; - } - return 0; -} - -/** Set up the siphash key if we haven't already done so. */ -int -crypto_init_siphash_key(void) -{ - static int have_seeded_siphash = 0; - 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; - - ERR_load_crypto_strings(); - OpenSSL_add_all_algorithms(); - - 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 - 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 - } 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 internally: quicly validate a crypto_pk_t object as a private key. - * Return 1 iff the public key is valid, 0 if obviously invalid. - */ -static int -crypto_pk_private_ok(const crypto_pk_t *k) -{ -#ifdef OPENSSL_1_1_API - if (!k || !k->key) - return 0; - - const BIGNUM *p, *q; - RSA_get0_factors(k->key, &p, &q); - return p != NULL; /* XXX/yawning: Should we check q? */ -#else - return k && k->key && k->key->p; -#endif -} - -/** used by tortls.c: wrap an RSA* in a crypto_pk_t. */ -crypto_pk_t * -crypto_new_pk_from_rsa_(RSA *rsa) -{ - crypto_pk_t *env; - tor_assert(rsa); - env = tor_malloc(sizeof(crypto_pk_t)); - env->refs = 1; - env->key = rsa; - return env; -} - -/** Helper, used by tor-checkkey.c and tor-gencert.c. Return the RSA from a - * crypto_pk_t. */ -RSA * -crypto_pk_get_rsa_(crypto_pk_t *env) -{ - return env->key; -} - -/** used by tortls.c: get an equivalent EVP_PKEY* for a crypto_pk_t. Iff - * private is set, include the private-key portion of the key. Return a valid - * pointer on success, and NULL on failure. */ -MOCK_IMPL(EVP_PKEY *, - crypto_pk_get_evp_pkey_,(crypto_pk_t *env, int private)) -{ - RSA *key = NULL; - EVP_PKEY *pkey = NULL; - tor_assert(env->key); - if (private) { - if (!(key = RSAPrivateKey_dup(env->key))) - goto error; - } else { - if (!(key = RSAPublicKey_dup(env->key))) - goto error; - } - if (!(pkey = EVP_PKEY_new())) - goto error; - if (!(EVP_PKEY_assign_RSA(pkey, key))) - goto error; - return pkey; - error: - if (pkey) - EVP_PKEY_free(pkey); - if (key) - RSA_free(key); - return NULL; -} - -/** 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 storage for a public key. The key itself will not yet - * be set. - */ -MOCK_IMPL(crypto_pk_t *, - crypto_pk_new,(void)) -{ - RSA *rsa; - - rsa = RSA_new(); - tor_assert(rsa); - return crypto_new_pk_from_rsa_(rsa); -} - -/** Release a reference to an asymmetric key; when all the references - * are released, free the key. - */ -void -crypto_pk_free(crypto_pk_t *env) -{ - if (!env) - return; - - if (--env->refs > 0) - return; - tor_assert(env->refs == 0); - - if (env->key) - RSA_free(env->key); - - tor_free(env); -} - -/** 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); -} - -/* public key crypto */ - -/** Generate a <b>bits</b>-bit new public/private keypair in <b>env</b>. - * Return 0 on success, -1 on failure. - */ -MOCK_IMPL(int, - crypto_pk_generate_key_with_bits,(crypto_pk_t *env, int bits)) -{ - tor_assert(env); - - if (env->key) { - RSA_free(env->key); - env->key = NULL; - } - - { - BIGNUM *e = BN_new(); - RSA *r = NULL; - if (!e) - goto done; - if (! BN_set_word(e, 65537)) - goto done; - r = RSA_new(); - if (!r) - goto done; - if (RSA_generate_key_ex(r, bits, e, NULL) == -1) - goto done; - - env->key = r; - r = NULL; - done: - if (e) - BN_clear_free(e); - if (r) - RSA_free(r); - } - - if (!env->key) { - crypto_log_errors(LOG_WARN, "generating RSA key"); - return -1; - } - - return 0; -} - -/** A PEM callback that always reports a failure to get a password */ -static int -pem_no_password_cb(char *buf, int size, int rwflag, void *u) -{ - (void)buf; - (void)size; - (void)rwflag; - (void)u; - /* The openssl documentation says that a callback "must" return 0 if an - * error occurred. But during the 1.1.1 series (commit c82c3462267afdbbaa5 - * they changed the interpretation so that 0 indicates an empty password and - * -1 indicates an error. We want to reject any encrypted PEM buffers, so we - * return -1. This will work on older OpenSSL versions and LibreSSL too. */ - return -1; -} - -/** Read a PEM-encoded private key from the <b>len</b>-byte string <b>s</b> - * into <b>env</b>. Return 0 on success, -1 on failure. If len is -1, - * the string is nul-terminated. - */ -int -crypto_pk_read_private_key_from_string(crypto_pk_t *env, - const char *s, ssize_t len) -{ - BIO *b; - - tor_assert(env); - tor_assert(s); - tor_assert(len < INT_MAX && len < SSIZE_T_CEILING); - - /* Create a read-only memory BIO, backed by the string 's' */ - b = BIO_new_mem_buf((char*)s, (int)len); - if (!b) - return -1; - - if (env->key) - RSA_free(env->key); - - env->key = PEM_read_bio_RSAPrivateKey(b,NULL,pem_no_password_cb,NULL); - - BIO_free(b); - - if (!env->key) { - crypto_log_errors(LOG_WARN, "Error parsing private key"); - return -1; - } - return 0; -} - -/** Read a PEM-encoded private key from the file named by - * <b>keyfile</b> into <b>env</b>. Return 0 on success, -1 on failure. - */ -int -crypto_pk_read_private_key_from_filename(crypto_pk_t *env, - const char *keyfile) -{ - char *contents; - int r; - - /* Read the file into a string. */ - contents = read_file_to_str(keyfile, 0, NULL); - if (!contents) { - log_warn(LD_CRYPTO, "Error reading private key from \"%s\"", keyfile); - return -1; - } - - /* Try to parse it. */ - r = crypto_pk_read_private_key_from_string(env, contents, -1); - memwipe(contents, 0, strlen(contents)); - tor_free(contents); - if (r) - return -1; /* read_private_key_from_string already warned, so we don't.*/ - - /* Make sure it's valid. */ - if (crypto_pk_check_key(env) <= 0) - return -1; - - return 0; -} - -/** Helper function to implement crypto_pk_write_*_key_to_string. Return 0 on - * success, -1 on failure. */ -static int -crypto_pk_write_key_to_string_impl(crypto_pk_t *env, char **dest, - size_t *len, int is_public) -{ - BUF_MEM *buf; - BIO *b; - int r; - - tor_assert(env); - tor_assert(env->key); - tor_assert(dest); - - b = BIO_new(BIO_s_mem()); /* Create a memory BIO */ - if (!b) - return -1; - - /* Now you can treat b as if it were a file. Just use the - * PEM_*_bio_* functions instead of the non-bio variants. - */ - if (is_public) - r = PEM_write_bio_RSAPublicKey(b, env->key); - else - r = PEM_write_bio_RSAPrivateKey(b, env->key, NULL,NULL,0,NULL,NULL); - - if (!r) { - crypto_log_errors(LOG_WARN, "writing RSA key to string"); - BIO_free(b); - return -1; - } - - BIO_get_mem_ptr(b, &buf); - - *dest = tor_malloc(buf->length+1); - memcpy(*dest, buf->data, buf->length); - (*dest)[buf->length] = 0; /* nul terminate it */ - *len = buf->length; - - BIO_free(b); - - return 0; -} - -/** PEM-encode the public key portion of <b>env</b> and write it to a - * newly allocated string. On success, set *<b>dest</b> to the new - * string, *<b>len</b> to the string's length, and return 0. On - * failure, return -1. - */ -int -crypto_pk_write_public_key_to_string(crypto_pk_t *env, char **dest, - size_t *len) -{ - return crypto_pk_write_key_to_string_impl(env, dest, len, 1); -} - -/** PEM-encode the private key portion of <b>env</b> and write it to a - * newly allocated string. On success, set *<b>dest</b> to the new - * string, *<b>len</b> to the string's length, and return 0. On - * failure, return -1. - */ -int -crypto_pk_write_private_key_to_string(crypto_pk_t *env, char **dest, - size_t *len) -{ - return crypto_pk_write_key_to_string_impl(env, dest, len, 0); -} - -/** Read a PEM-encoded public key from the first <b>len</b> characters of - * <b>src</b>, and store the result in <b>env</b>. Return 0 on success, -1 on - * failure. - */ -int -crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src, - size_t len) -{ - BIO *b; - - tor_assert(env); - tor_assert(src); - tor_assert(len<INT_MAX); - - b = BIO_new(BIO_s_mem()); /* Create a memory BIO */ - if (!b) - return -1; - - BIO_write(b, src, (int)len); - - if (env->key) - RSA_free(env->key); - env->key = PEM_read_bio_RSAPublicKey(b, NULL, pem_no_password_cb, NULL); - BIO_free(b); - if (!env->key) { - crypto_log_errors(LOG_WARN, "reading public key from string"); - return -1; - } - - return 0; -} - -/** Write the private key from <b>env</b> into the file named by <b>fname</b>, - * PEM-encoded. Return 0 on success, -1 on failure. - */ -int -crypto_pk_write_private_key_to_filename(crypto_pk_t *env, - const char *fname) -{ - BIO *bio; - char *cp; - long len; - char *s; - int r; - - tor_assert(crypto_pk_private_ok(env)); - - if (!(bio = BIO_new(BIO_s_mem()))) - return -1; - if (PEM_write_bio_RSAPrivateKey(bio, env->key, NULL,NULL,0,NULL,NULL) - == 0) { - crypto_log_errors(LOG_WARN, "writing private key"); - BIO_free(bio); - return -1; - } - len = BIO_get_mem_data(bio, &cp); - tor_assert(len >= 0); - s = tor_malloc(len+1); - memcpy(s, cp, len); - s[len]='\0'; - r = write_str_to_file(fname, s, 0); - BIO_free(bio); - memwipe(s, 0, strlen(s)); - tor_free(s); - return r; -} - -/** Return true iff <b>env</b> has a valid key. - */ -int -crypto_pk_check_key(crypto_pk_t *env) -{ - int r; - tor_assert(env); - - r = RSA_check_key(env->key); - if (r <= 0) - crypto_log_errors(LOG_WARN,"checking RSA key"); - return r; -} - -/** Return true iff <b>key</b> contains the private-key portion of the RSA - * key. */ -int -crypto_pk_key_is_private(const crypto_pk_t *key) -{ - tor_assert(key); - return crypto_pk_private_ok(key); -} - -/** Return true iff <b>env</b> contains a public key whose public exponent - * equals 65537. - */ -int -crypto_pk_public_exponent_ok(crypto_pk_t *env) -{ - tor_assert(env); - tor_assert(env->key); - - const BIGNUM *e; - -#ifdef OPENSSL_1_1_API - const BIGNUM *n, *d; - RSA_get0_key(env->key, &n, &e, &d); -#else - e = env->key->e; -#endif - return BN_is_word(e, 65537); -} - -/** Compare the public-key components of a and b. Return less than 0 - * if a\<b, 0 if a==b, and greater than 0 if a\>b. A NULL key is - * considered to be less than all non-NULL keys, and equal to itself. - * - * Note that this may leak information about the keys through timing. - */ -int -crypto_pk_cmp_keys(const crypto_pk_t *a, const crypto_pk_t *b) -{ - int result; - char a_is_non_null = (a != NULL) && (a->key != NULL); - char b_is_non_null = (b != NULL) && (b->key != NULL); - char an_argument_is_null = !a_is_non_null | !b_is_non_null; - - result = tor_memcmp(&a_is_non_null, &b_is_non_null, sizeof(a_is_non_null)); - if (an_argument_is_null) - return result; - - const BIGNUM *a_n, *a_e; - const BIGNUM *b_n, *b_e; - -#ifdef OPENSSL_1_1_API - const BIGNUM *a_d, *b_d; - RSA_get0_key(a->key, &a_n, &a_e, &a_d); - RSA_get0_key(b->key, &b_n, &b_e, &b_d); -#else - a_n = a->key->n; - a_e = a->key->e; - b_n = b->key->n; - b_e = b->key->e; -#endif - - tor_assert(a_n != NULL && a_e != NULL); - tor_assert(b_n != NULL && b_e != NULL); - - result = BN_cmp(a_n, b_n); - if (result) - return result; - return BN_cmp(a_e, b_e); -} - -/** Compare the public-key components of a and b. Return non-zero iff - * a==b. A NULL key is considered to be distinct from all non-NULL - * keys, and equal to itself. - * - * Note that this may leak information about the keys through timing. - */ -int -crypto_pk_eq_keys(const crypto_pk_t *a, const crypto_pk_t *b) -{ - return (crypto_pk_cmp_keys(a, b) == 0); -} - -/** Return the size of the public key modulus in <b>env</b>, in bytes. */ -size_t -crypto_pk_keysize(const crypto_pk_t *env) -{ - tor_assert(env); - tor_assert(env->key); - - return (size_t) RSA_size((RSA*)env->key); -} - -/** Return the size of the public key modulus of <b>env</b>, in bits. */ -int -crypto_pk_num_bits(crypto_pk_t *env) -{ - tor_assert(env); - tor_assert(env->key); - -#ifdef OPENSSL_1_1_API - /* It's so stupid that there's no other way to check that n is valid - * before calling RSA_bits(). - */ - const BIGNUM *n, *e, *d; - RSA_get0_key(env->key, &n, &e, &d); - tor_assert(n != NULL); - - return RSA_bits(env->key); -#else - tor_assert(env->key->n); - return BN_num_bits(env->key->n); -#endif -} - -/** Increase the reference count of <b>env</b>, and return it. - */ -crypto_pk_t * -crypto_pk_dup_key(crypto_pk_t *env) -{ - tor_assert(env); - tor_assert(env->key); - - env->refs++; - return env; -} - -#ifdef TOR_UNIT_TESTS -/** For testing: replace dest with src. (Dest must have a refcount - * of 1) */ -void -crypto_pk_assign_(crypto_pk_t *dest, const crypto_pk_t *src) -{ - tor_assert(dest); - tor_assert(dest->refs == 1); - tor_assert(src); - RSA_free(dest->key); - dest->key = RSAPrivateKey_dup(src->key); -} -#endif - -/** Make a real honest-to-goodness copy of <b>env</b>, and return it. - * Returns NULL on failure. */ -crypto_pk_t * -crypto_pk_copy_full(crypto_pk_t *env) -{ - RSA *new_key; - int privatekey = 0; - tor_assert(env); - tor_assert(env->key); - - if (crypto_pk_private_ok(env)) { - new_key = RSAPrivateKey_dup(env->key); - privatekey = 1; - } else { - new_key = RSAPublicKey_dup(env->key); - } - if (!new_key) { - /* LCOV_EXCL_START - * - * We can't cause RSA*Key_dup() to fail, so we can't really test this. - */ - log_err(LD_CRYPTO, "Unable to duplicate a %s key: openssl failed.", - privatekey?"private":"public"); - crypto_log_errors(LOG_ERR, - privatekey ? "Duplicating a private key" : - "Duplicating a public key"); - tor_fragile_assert(); - return NULL; - /* LCOV_EXCL_STOP */ - } - - return crypto_new_pk_from_rsa_(new_key); -} - -/** Encrypt <b>fromlen</b> bytes from <b>from</b> with the public key - * in <b>env</b>, using the padding method <b>padding</b>. On success, - * write the result to <b>to</b>, and return the number of bytes - * written. On failure, return -1. - * - * <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be - * at least the length of the modulus of <b>env</b>. - */ -int -crypto_pk_public_encrypt(crypto_pk_t *env, char *to, size_t tolen, - const char *from, size_t fromlen, int padding) -{ - int r; - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen<INT_MAX); - tor_assert(tolen >= crypto_pk_keysize(env)); - - r = RSA_public_encrypt((int)fromlen, - (unsigned char*)from, (unsigned char*)to, - env->key, crypto_get_rsa_padding(padding)); - if (r<0) { - crypto_log_errors(LOG_WARN, "performing RSA encryption"); - return -1; - } - return r; -} - -/** Decrypt <b>fromlen</b> bytes from <b>from</b> with the private key - * in <b>env</b>, using the padding method <b>padding</b>. On success, - * write the result to <b>to</b>, and return the number of bytes - * written. On failure, return -1. - * - * <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be - * at least the length of the modulus of <b>env</b>. - */ -int -crypto_pk_private_decrypt(crypto_pk_t *env, char *to, - size_t tolen, - const char *from, size_t fromlen, - int padding, int warnOnFailure) -{ - int r; - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(env->key); - tor_assert(fromlen<INT_MAX); - tor_assert(tolen >= crypto_pk_keysize(env)); - if (!crypto_pk_key_is_private(env)) - /* Not a private key */ - return -1; - - r = RSA_private_decrypt((int)fromlen, - (unsigned char*)from, (unsigned char*)to, - env->key, crypto_get_rsa_padding(padding)); - - if (r<0) { - crypto_log_errors(warnOnFailure?LOG_WARN:LOG_DEBUG, - "performing RSA decryption"); - return -1; - } - return r; -} - -/** Check the signature in <b>from</b> (<b>fromlen</b> bytes long) with the - * public key in <b>env</b>, using PKCS1 padding. On success, write the - * signed data to <b>to</b>, and return the number of bytes written. - * On failure, return -1. - * - * <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be - * at least the length of the modulus of <b>env</b>. - */ -int -crypto_pk_public_checksig(const crypto_pk_t *env, char *to, - size_t tolen, - const char *from, size_t fromlen) -{ - int r; - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < INT_MAX); - tor_assert(tolen >= crypto_pk_keysize(env)); - r = RSA_public_decrypt((int)fromlen, - (unsigned char*)from, (unsigned char*)to, - env->key, RSA_PKCS1_PADDING); - - if (r<0) { - crypto_log_errors(LOG_INFO, "checking RSA signature"); - return -1; - } - return r; -} - -/** Check a siglen-byte long signature at <b>sig</b> against - * <b>datalen</b> bytes of data at <b>data</b>, using the public key - * in <b>env</b>. Return 0 if <b>sig</b> is a correct signature for - * SHA1(data). Else return -1. - */ -int -crypto_pk_public_checksig_digest(crypto_pk_t *env, const char *data, - size_t datalen, const char *sig, size_t siglen) -{ - char digest[DIGEST_LEN]; - char *buf; - size_t buflen; - int r; - - tor_assert(env); - tor_assert(data); - tor_assert(sig); - tor_assert(datalen < SIZE_T_CEILING); - tor_assert(siglen < SIZE_T_CEILING); - - if (crypto_digest(digest,data,datalen)<0) { - log_warn(LD_BUG, "couldn't compute digest"); - return -1; - } - buflen = crypto_pk_keysize(env); - buf = tor_malloc(buflen); - r = crypto_pk_public_checksig(env,buf,buflen,sig,siglen); - if (r != DIGEST_LEN) { - log_warn(LD_CRYPTO, "Invalid signature"); - tor_free(buf); - return -1; - } - if (tor_memneq(buf, digest, DIGEST_LEN)) { - log_warn(LD_CRYPTO, "Signature mismatched with digest."); - tor_free(buf); - return -1; - } - tor_free(buf); - - return 0; -} - -/** Sign <b>fromlen</b> bytes of data from <b>from</b> with the private key in - * <b>env</b>, using PKCS1 padding. On success, write the signature to - * <b>to</b>, and return the number of bytes written. On failure, return - * -1. - * - * <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be - * at least the length of the modulus of <b>env</b>. - */ -int -crypto_pk_private_sign(const crypto_pk_t *env, char *to, size_t tolen, - const char *from, size_t fromlen) -{ - int r; - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < INT_MAX); - tor_assert(tolen >= crypto_pk_keysize(env)); - if (!crypto_pk_key_is_private(env)) - /* Not a private key */ - return -1; - - r = RSA_private_encrypt((int)fromlen, - (unsigned char*)from, (unsigned char*)to, - (RSA*)env->key, RSA_PKCS1_PADDING); - if (r<0) { - crypto_log_errors(LOG_WARN, "generating RSA signature"); - return -1; - } - return r; -} - -/** Compute a SHA1 digest of <b>fromlen</b> bytes of data stored at - * <b>from</b>; sign the data with the private key in <b>env</b>, and - * store it in <b>to</b>. Return the number of bytes written on - * success, and -1 on failure. - * - * <b>tolen</b> is the number of writable bytes in <b>to</b>, and must be - * at least the length of the modulus of <b>env</b>. - */ -int -crypto_pk_private_sign_digest(crypto_pk_t *env, char *to, size_t tolen, - const char *from, size_t fromlen) -{ - int r; - char digest[DIGEST_LEN]; - if (crypto_digest(digest,from,fromlen)<0) - return -1; - r = crypto_pk_private_sign(env,to,tolen,digest,DIGEST_LEN); - memwipe(digest, 0, sizeof(digest)); - return r; -} - -/** Perform a hybrid (public/secret) encryption on <b>fromlen</b> - * bytes of data from <b>from</b>, with padding type 'padding', - * storing the results on <b>to</b>. - * - * Returns the number of bytes written on success, -1 on failure. - * - * The encrypted data consists of: - * - The source data, padded and encrypted with the public key, if the - * padded source data is no longer than the public key, and <b>force</b> - * is false, OR - * - The beginning of the source data prefixed with a 16-byte symmetric key, - * padded and encrypted with the public key; followed by the rest of - * the source data encrypted in AES-CTR mode with the symmetric key. - */ -int -crypto_pk_public_hybrid_encrypt(crypto_pk_t *env, - char *to, size_t tolen, - const char *from, - size_t fromlen, - int padding, int force) -{ - int overhead, outlen, r; - size_t pkeylen, symlen; - crypto_cipher_t *cipher = NULL; - char *buf = NULL; - - tor_assert(env); - tor_assert(from); - tor_assert(to); - tor_assert(fromlen < SIZE_T_CEILING); - - overhead = crypto_get_rsa_padding_overhead(crypto_get_rsa_padding(padding)); - pkeylen = crypto_pk_keysize(env); - - if (!force && fromlen+overhead <= pkeylen) { - /* It all fits in a single encrypt. */ - return crypto_pk_public_encrypt(env,to, - tolen, - from,fromlen,padding); - } - tor_assert(tolen >= fromlen + overhead + CIPHER_KEY_LEN); - tor_assert(tolen >= pkeylen); - - char key[CIPHER_KEY_LEN]; - crypto_rand(key, sizeof(key)); /* generate a new key. */ - cipher = crypto_cipher_new(key); - - buf = tor_malloc(pkeylen+1); - memcpy(buf, key, CIPHER_KEY_LEN); - memcpy(buf+CIPHER_KEY_LEN, from, pkeylen-overhead-CIPHER_KEY_LEN); - - /* Length of symmetrically encrypted data. */ - symlen = fromlen-(pkeylen-overhead-CIPHER_KEY_LEN); - - outlen = crypto_pk_public_encrypt(env,to,tolen,buf,pkeylen-overhead,padding); - if (outlen!=(int)pkeylen) { - goto err; - } - r = crypto_cipher_encrypt(cipher, to+outlen, - from+pkeylen-overhead-CIPHER_KEY_LEN, symlen); - - if (r<0) goto err; - memwipe(buf, 0, pkeylen); - memwipe(key, 0, sizeof(key)); - tor_free(buf); - crypto_cipher_free(cipher); - tor_assert(outlen+symlen < INT_MAX); - return (int)(outlen + symlen); - err: - - memwipe(buf, 0, pkeylen); - memwipe(key, 0, sizeof(key)); - tor_free(buf); - crypto_cipher_free(cipher); - return -1; -} - -/** Invert crypto_pk_public_hybrid_encrypt. Returns the number of bytes - * written on success, -1 on failure. */ -int -crypto_pk_private_hybrid_decrypt(crypto_pk_t *env, - char *to, - size_t tolen, - const char *from, - size_t fromlen, - int padding, int warnOnFailure) -{ - int outlen, r; - size_t pkeylen; - crypto_cipher_t *cipher = NULL; - char *buf = NULL; - - tor_assert(fromlen < SIZE_T_CEILING); - pkeylen = crypto_pk_keysize(env); - - if (fromlen <= pkeylen) { - return crypto_pk_private_decrypt(env,to,tolen,from,fromlen,padding, - warnOnFailure); - } - - buf = tor_malloc(pkeylen); - outlen = crypto_pk_private_decrypt(env,buf,pkeylen,from,pkeylen,padding, - warnOnFailure); - if (outlen<0) { - log_fn(warnOnFailure?LOG_WARN:LOG_DEBUG, LD_CRYPTO, - "Error decrypting public-key data"); - goto err; - } - if (outlen < CIPHER_KEY_LEN) { - log_fn(warnOnFailure?LOG_WARN:LOG_INFO, LD_CRYPTO, - "No room for a symmetric key"); - goto err; - } - cipher = crypto_cipher_new(buf); - if (!cipher) { - goto err; - } - memcpy(to,buf+CIPHER_KEY_LEN,outlen-CIPHER_KEY_LEN); - outlen -= CIPHER_KEY_LEN; - tor_assert(tolen - outlen >= fromlen - pkeylen); - r = crypto_cipher_decrypt(cipher, to+outlen, from+pkeylen, fromlen-pkeylen); - if (r<0) - goto err; - memwipe(buf,0,pkeylen); - tor_free(buf); - crypto_cipher_free(cipher); - tor_assert(outlen + fromlen < INT_MAX); - return (int)(outlen + (fromlen-pkeylen)); - err: - memwipe(buf,0,pkeylen); - tor_free(buf); - crypto_cipher_free(cipher); - return -1; -} - -/** ASN.1-encode the public portion of <b>pk</b> into <b>dest</b>. - * Return -1 on error, or the number of characters used on success. - */ -int -crypto_pk_asn1_encode(crypto_pk_t *pk, char *dest, size_t dest_len) -{ - int len; - unsigned char *buf = NULL; - - len = i2d_RSAPublicKey(pk->key, &buf); - if (len < 0 || buf == NULL) - return -1; - - if ((size_t)len > dest_len || dest_len > SIZE_T_CEILING) { - OPENSSL_free(buf); - return -1; - } - /* We don't encode directly into 'dest', because that would be illegal - * type-punning. (C99 is smarter than me, C99 is smarter than me...) - */ - memcpy(dest,buf,len); - OPENSSL_free(buf); - return len; -} - -/** Decode an ASN.1-encoded public key from <b>str</b>; return the result on - * success and NULL on failure. - */ -crypto_pk_t * -crypto_pk_asn1_decode(const char *str, size_t len) -{ - RSA *rsa; - unsigned char *buf; - const unsigned char *cp; - cp = buf = tor_malloc(len); - memcpy(buf,str,len); - rsa = d2i_RSAPublicKey(NULL, &cp, len); - tor_free(buf); - if (!rsa) { - crypto_log_errors(LOG_WARN,"decoding public key"); - return NULL; - } - return crypto_new_pk_from_rsa_(rsa); -} - -/** Given a private or public key <b>pk</b>, put a SHA1 hash of the - * public key into <b>digest_out</b> (must have DIGEST_LEN bytes of space). - * Return 0 on success, -1 on failure. - */ -int -crypto_pk_get_digest(const crypto_pk_t *pk, char *digest_out) -{ - unsigned char *buf = NULL; - int len; - - len = i2d_RSAPublicKey((RSA*)pk->key, &buf); - if (len < 0 || buf == NULL) - return -1; - if (crypto_digest(digest_out, (char*)buf, len) < 0) { - OPENSSL_free(buf); - return -1; - } - OPENSSL_free(buf); - return 0; -} - -/** Compute all digests of the DER encoding of <b>pk</b>, and store them - * in <b>digests_out</b>. Return 0 on success, -1 on failure. */ -int -crypto_pk_get_common_digests(crypto_pk_t *pk, common_digests_t *digests_out) -{ - unsigned char *buf = NULL; - int len; - - len = i2d_RSAPublicKey(pk->key, &buf); - if (len < 0 || buf == NULL) - return -1; - if (crypto_common_digests(digests_out, (char*)buf, len) < 0) { - OPENSSL_free(buf); - return -1; - } - OPENSSL_free(buf); - return 0; -} - -/** 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'; -} - -/** Given a private or public key <b>pk</b>, put a fingerprint of the - * public key into <b>fp_out</b> (must have at least FINGERPRINT_LEN+1 bytes of - * space). Return 0 on success, -1 on failure. - * - * Fingerprints are computed as the SHA1 digest of the ASN.1 encoding - * of the public key, converted to hexadecimal, in upper case, with a - * space after every four digits. - * - * If <b>add_space</b> is false, omit the spaces. - */ -int -crypto_pk_get_fingerprint(crypto_pk_t *pk, char *fp_out, int add_space) -{ - char digest[DIGEST_LEN]; - char hexdigest[HEX_DIGEST_LEN+1]; - if (crypto_pk_get_digest(pk, digest)) { - return -1; - } - base16_encode(hexdigest,sizeof(hexdigest),digest,DIGEST_LEN); - if (add_space) { - crypto_add_spaces_to_fp(fp_out, FINGERPRINT_LEN+1, hexdigest); - } else { - strncpy(fp_out, hexdigest, HEX_DIGEST_LEN+1); - } - return 0; -} - -/** Given a private or public key <b>pk</b>, put a hashed fingerprint of - * the public key into <b>fp_out</b> (must have at least FINGERPRINT_LEN+1 - * bytes of space). Return 0 on success, -1 on failure. - * - * Hashed fingerprints are computed as the SHA1 digest of the SHA1 digest - * of the ASN.1 encoding of the public key, converted to hexadecimal, in - * upper case. - */ -int -crypto_pk_get_hashed_fingerprint(crypto_pk_t *pk, char *fp_out) -{ - char digest[DIGEST_LEN], hashed_digest[DIGEST_LEN]; - if (crypto_pk_get_digest(pk, digest)) { - return -1; - } - if (crypto_digest(hashed_digest, digest, DIGEST_LEN)) { - return -1; - } - base16_encode(fp_out, FINGERPRINT_LEN + 1, hashed_digest, DIGEST_LEN); - return 0; -} - -/** Given a crypto_pk_t <b>pk</b>, allocate a new buffer containing the - * Base64 encoding of the DER representation of the private key as a NUL - * terminated string, and return it via <b>priv_out</b>. Return 0 on - * sucess, -1 on failure. - * - * It is the caller's responsibility to sanitize and free the resulting buffer. - */ -int -crypto_pk_base64_encode(const crypto_pk_t *pk, char **priv_out) -{ - unsigned char *der = NULL; - int der_len; - int ret = -1; - - *priv_out = NULL; - - der_len = i2d_RSAPrivateKey(pk->key, &der); - if (der_len < 0 || der == NULL) - return ret; - - size_t priv_len = base64_encode_size(der_len, 0) + 1; - char *priv = tor_malloc_zero(priv_len); - if (base64_encode(priv, priv_len, (char *)der, der_len, 0) >= 0) { - *priv_out = priv; - ret = 0; - } else { - tor_free(priv); - } - - memwipe(der, 0, der_len); - OPENSSL_free(der); - return ret; -} - -/** Given a string containing the Base64 encoded DER representation of the - * private key <b>str</b>, decode and return the result on success, or NULL - * on failure. - */ -crypto_pk_t * -crypto_pk_base64_decode(const char *str, size_t len) -{ - crypto_pk_t *pk = NULL; - - char *der = tor_malloc_zero(len + 1); - int der_len = base64_decode(der, len, str, len); - if (der_len <= 0) { - log_warn(LD_CRYPTO, "Stored RSA private key seems corrupted (base64)."); - goto out; - } - - const unsigned char *dp = (unsigned char*)der; /* Shut the compiler up. */ - RSA *rsa = d2i_RSAPrivateKey(NULL, &dp, der_len); - if (!rsa) { - crypto_log_errors(LOG_WARN, "decoding private key"); - goto out; - } - - pk = crypto_new_pk_from_rsa_(rsa); - - /* Make sure it's valid. */ - if (crypto_pk_check_key(pk) <= 0) { - crypto_pk_free(pk); - pk = NULL; - goto out; - } - - out: - memwipe(der, 0, len + 1); - tor_free(der); - return pk; -} - -/* 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); -} - -/* SHA-1 */ - -/** Compute the SHA1 digest of the <b>len</b> bytes on data stored in - * <b>m</b>. Write the DIGEST_LEN byte result into <b>digest</b>. - * Return 0 on success, 1 on failure. - */ -int -crypto_digest(char *digest, const char *m, size_t len) -{ - tor_assert(m); - tor_assert(digest); - return (SHA1((const unsigned char*)m,len,(unsigned char*)digest) == NULL); -} - -/** Compute a 256-bit digest of <b>len</b> bytes in data stored in <b>m</b>, - * using the algorithm <b>algorithm</b>. Write the DIGEST_LEN256-byte result - * into <b>digest</b>. Return 0 on success, 1 on failure. */ -int -crypto_digest256(char *digest, const char *m, size_t len, - digest_algorithm_t algorithm) -{ - tor_assert(m); - tor_assert(digest); - tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256); - if (algorithm == DIGEST_SHA256) - return (SHA256((const uint8_t*)m,len,(uint8_t*)digest) == NULL); - else - return (sha3_256((uint8_t *)digest, DIGEST256_LEN,(const uint8_t *)m, len) - == -1); -} - -/** Compute a 512-bit digest of <b>len</b> bytes in data stored in <b>m</b>, - * using the algorithm <b>algorithm</b>. Write the DIGEST_LEN512-byte result - * into <b>digest</b>. Return 0 on success, 1 on failure. */ -int -crypto_digest512(char *digest, const char *m, size_t len, - digest_algorithm_t algorithm) -{ - tor_assert(m); - tor_assert(digest); - tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512); - if (algorithm == DIGEST_SHA512) - return (SHA512((const unsigned char*)m,len,(unsigned char*)digest) - == NULL); - else - return (sha3_512((uint8_t*)digest, DIGEST512_LEN, (const uint8_t*)m, len) - == -1); -} - -/** Set the common_digests_t in <b>ds_out</b> to contain every digest on the - * <b>len</b> bytes in <b>m</b> that we know how to compute. Return 0 on - * success, -1 on failure. */ -int -crypto_common_digests(common_digests_t *ds_out, const char *m, size_t len) -{ - tor_assert(ds_out); - memset(ds_out, 0, sizeof(*ds_out)); - if (crypto_digest(ds_out->d[DIGEST_SHA1], m, len) < 0) - return -1; - if (crypto_digest256(ds_out->d[DIGEST_SHA256], m, len, DIGEST_SHA256) < 0) - return -1; - - return 0; -} - -/** Return the name of an algorithm, as used in directory documents. */ -const char * -crypto_digest_algorithm_get_name(digest_algorithm_t alg) -{ - switch (alg) { - case DIGEST_SHA1: - return "sha1"; - case DIGEST_SHA256: - return "sha256"; - case DIGEST_SHA512: - return "sha512"; - case DIGEST_SHA3_256: - return "sha3-256"; - case DIGEST_SHA3_512: - return "sha3-512"; - default: - // LCOV_EXCL_START - tor_fragile_assert(); - return "??unknown_digest??"; - // LCOV_EXCL_STOP - } -} - -/** Given the name of a digest algorithm, return its integer value, or -1 if - * the name is not recognized. */ -int -crypto_digest_algorithm_parse_name(const char *name) -{ - if (!strcmp(name, "sha1")) - return DIGEST_SHA1; - else if (!strcmp(name, "sha256")) - return DIGEST_SHA256; - else if (!strcmp(name, "sha512")) - return DIGEST_SHA512; - else if (!strcmp(name, "sha3-256")) - return DIGEST_SHA3_256; - else if (!strcmp(name, "sha3-512")) - return DIGEST_SHA3_512; - else - return -1; -} - -/** Given an algorithm, return the digest length in bytes. */ -size_t -crypto_digest_algorithm_get_length(digest_algorithm_t alg) -{ - switch (alg) { - case DIGEST_SHA1: - return DIGEST_LEN; - case DIGEST_SHA256: - return DIGEST256_LEN; - case DIGEST_SHA512: - return DIGEST512_LEN; - case DIGEST_SHA3_256: - return DIGEST256_LEN; - case DIGEST_SHA3_512: - return DIGEST512_LEN; - default: - tor_assert(0); // LCOV_EXCL_LINE - return 0; /* Unreachable */ // LCOV_EXCL_LINE - } -} - -/** Intermediate information about the digest of a stream of data. */ -struct crypto_digest_t { - digest_algorithm_t algorithm; /**< Which algorithm is in use? */ - /** State for the digest we're using. Only one member of the - * union is usable, depending on the value of <b>algorithm</b>. Note also - * that space for other members might not even be allocated! - */ - union { - SHA_CTX sha1; /**< state for SHA1 */ - SHA256_CTX sha2; /**< state for SHA256 */ - SHA512_CTX sha512; /**< state for SHA512 */ - keccak_state sha3; /**< state for SHA3-[256,512] */ - } d; -}; - -/** - * Return the number of bytes we need to malloc in order to get a - * crypto_digest_t for <b>alg</b>, or the number of bytes we need to wipe - * when we free one. - */ -static size_t -crypto_digest_alloc_bytes(digest_algorithm_t alg) -{ - /* Helper: returns the number of bytes in the 'f' field of 'st' */ -#define STRUCT_FIELD_SIZE(st, f) (sizeof( ((st*)0)->f )) - /* Gives the length of crypto_digest_t through the end of the field 'd' */ -#define END_OF_FIELD(f) (STRUCT_OFFSET(crypto_digest_t, f) + \ - STRUCT_FIELD_SIZE(crypto_digest_t, f)) - switch (alg) { - case DIGEST_SHA1: - return END_OF_FIELD(d.sha1); - case DIGEST_SHA256: - return END_OF_FIELD(d.sha2); - case DIGEST_SHA512: - return END_OF_FIELD(d.sha512); - case DIGEST_SHA3_256: - case DIGEST_SHA3_512: - return END_OF_FIELD(d.sha3); - default: - tor_assert(0); // LCOV_EXCL_LINE - return 0; // LCOV_EXCL_LINE - } -#undef END_OF_FIELD -#undef STRUCT_FIELD_SIZE -} - -/** - * Internal function: create and return a new digest object for 'algorithm'. - * Does not typecheck the algorithm. - */ -static crypto_digest_t * -crypto_digest_new_internal(digest_algorithm_t algorithm) -{ - crypto_digest_t *r = tor_malloc(crypto_digest_alloc_bytes(algorithm)); - r->algorithm = algorithm; - - switch (algorithm) - { - case DIGEST_SHA1: - SHA1_Init(&r->d.sha1); - break; - case DIGEST_SHA256: - SHA256_Init(&r->d.sha2); - break; - case DIGEST_SHA512: - SHA512_Init(&r->d.sha512); - break; - case DIGEST_SHA3_256: - keccak_digest_init(&r->d.sha3, 256); - break; - case DIGEST_SHA3_512: - keccak_digest_init(&r->d.sha3, 512); - break; - default: - tor_assert_unreached(); - } - - return r; -} - -/** Allocate and return a new digest object to compute SHA1 digests. - */ -crypto_digest_t * -crypto_digest_new(void) -{ - return crypto_digest_new_internal(DIGEST_SHA1); -} - -/** Allocate and return a new digest object to compute 256-bit digests - * using <b>algorithm</b>. */ -crypto_digest_t * -crypto_digest256_new(digest_algorithm_t algorithm) -{ - tor_assert(algorithm == DIGEST_SHA256 || algorithm == DIGEST_SHA3_256); - return crypto_digest_new_internal(algorithm); -} - -/** Allocate and return a new digest object to compute 512-bit digests - * using <b>algorithm</b>. */ -crypto_digest_t * -crypto_digest512_new(digest_algorithm_t algorithm) -{ - tor_assert(algorithm == DIGEST_SHA512 || algorithm == DIGEST_SHA3_512); - return crypto_digest_new_internal(algorithm); -} - -/** Deallocate a digest object. - */ -void -crypto_digest_free(crypto_digest_t *digest) -{ - if (!digest) - return; - size_t bytes = crypto_digest_alloc_bytes(digest->algorithm); - memwipe(digest, 0, bytes); - tor_free(digest); -} - -/** Add <b>len</b> bytes from <b>data</b> to the digest object. - */ -void -crypto_digest_add_bytes(crypto_digest_t *digest, const char *data, - size_t len) -{ - tor_assert(digest); - tor_assert(data); - /* Using the SHA*_*() calls directly means we don't support doing - * SHA in hardware. But so far the delay of getting the question - * to the hardware, and hearing the answer, is likely higher than - * just doing it ourselves. Hashes are fast. - */ - switch (digest->algorithm) { - case DIGEST_SHA1: - SHA1_Update(&digest->d.sha1, (void*)data, len); - break; - case DIGEST_SHA256: - SHA256_Update(&digest->d.sha2, (void*)data, len); - break; - case DIGEST_SHA512: - SHA512_Update(&digest->d.sha512, (void*)data, len); - break; - case DIGEST_SHA3_256: /* FALLSTHROUGH */ - case DIGEST_SHA3_512: - keccak_digest_update(&digest->d.sha3, (const uint8_t *)data, len); - break; - default: - /* LCOV_EXCL_START */ - tor_fragile_assert(); - break; - /* LCOV_EXCL_STOP */ - } -} - -/** Compute the hash of the data that has been passed to the digest - * object; write the first out_len bytes of the result to <b>out</b>. - * <b>out_len</b> must be \<= DIGEST512_LEN. - */ -void -crypto_digest_get_digest(crypto_digest_t *digest, - char *out, size_t out_len) -{ - unsigned char r[DIGEST512_LEN]; - crypto_digest_t tmpenv; - tor_assert(digest); - tor_assert(out); - tor_assert(out_len <= crypto_digest_algorithm_get_length(digest->algorithm)); - - /* The SHA-3 code handles copying into a temporary ctx, and also can handle - * short output buffers by truncating appropriately. */ - if (digest->algorithm == DIGEST_SHA3_256 || - digest->algorithm == DIGEST_SHA3_512) { - keccak_digest_sum(&digest->d.sha3, (uint8_t *)out, out_len); - return; - } - - const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm); - /* memcpy into a temporary ctx, since SHA*_Final clears the context */ - memcpy(&tmpenv, digest, alloc_bytes); - switch (digest->algorithm) { - case DIGEST_SHA1: - SHA1_Final(r, &tmpenv.d.sha1); - break; - case DIGEST_SHA256: - SHA256_Final(r, &tmpenv.d.sha2); - break; - case DIGEST_SHA512: - SHA512_Final(r, &tmpenv.d.sha512); - break; -//LCOV_EXCL_START - case DIGEST_SHA3_256: /* FALLSTHROUGH */ - case DIGEST_SHA3_512: - default: - log_warn(LD_BUG, "Handling unexpected algorithm %d", digest->algorithm); - /* This is fatal, because it should never happen. */ - tor_assert_unreached(); - break; -//LCOV_EXCL_STOP - } - memcpy(out, r, out_len); - memwipe(r, 0, sizeof(r)); -} - -/** Allocate and return a new digest object with the same state as - * <b>digest</b> - */ -crypto_digest_t * -crypto_digest_dup(const crypto_digest_t *digest) -{ - tor_assert(digest); - const size_t alloc_bytes = crypto_digest_alloc_bytes(digest->algorithm); - return tor_memdup(digest, alloc_bytes); -} - -/** Replace the state of the digest object <b>into</b> with the state - * of the digest object <b>from</b>. Requires that 'into' and 'from' - * have the same digest type. - */ -void -crypto_digest_assign(crypto_digest_t *into, - const crypto_digest_t *from) -{ - tor_assert(into); - tor_assert(from); - tor_assert(into->algorithm == from->algorithm); - const size_t alloc_bytes = crypto_digest_alloc_bytes(from->algorithm); - memcpy(into,from,alloc_bytes); -} - -/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest - * at <b>digest_out</b> to the hash of the concatenation of those strings, - * plus the optional string <b>append</b>, computed with the algorithm - * <b>alg</b>. - * <b>out_len</b> must be \<= DIGEST512_LEN. */ -void -crypto_digest_smartlist(char *digest_out, size_t len_out, - const smartlist_t *lst, - const char *append, - digest_algorithm_t alg) -{ - crypto_digest_smartlist_prefix(digest_out, len_out, NULL, lst, append, alg); -} - -/** Given a list of strings in <b>lst</b>, set the <b>len_out</b>-byte digest - * at <b>digest_out</b> to the hash of the concatenation of: the - * optional string <b>prepend</b>, those strings, - * and the optional string <b>append</b>, computed with the algorithm - * <b>alg</b>. - * <b>len_out</b> must be \<= DIGEST512_LEN. */ -void -crypto_digest_smartlist_prefix(char *digest_out, size_t len_out, - const char *prepend, - const smartlist_t *lst, - const char *append, - digest_algorithm_t alg) -{ - crypto_digest_t *d = crypto_digest_new_internal(alg); - if (prepend) - crypto_digest_add_bytes(d, prepend, strlen(prepend)); - SMARTLIST_FOREACH(lst, const char *, cp, - crypto_digest_add_bytes(d, cp, strlen(cp))); - if (append) - crypto_digest_add_bytes(d, append, strlen(append)); - crypto_digest_get_digest(d, digest_out, len_out); - crypto_digest_free(d); -} - -/** Compute the HMAC-SHA-256 of the <b>msg_len</b> bytes in <b>msg</b>, using - * the <b>key</b> of length <b>key_len</b>. Store the DIGEST256_LEN-byte - * result in <b>hmac_out</b>. Asserts on failure. - */ -void -crypto_hmac_sha256(char *hmac_out, - const char *key, size_t key_len, - const char *msg, size_t msg_len) -{ - unsigned char *rv = NULL; - /* If we've got OpenSSL >=0.9.8 we can use its hmac implementation. */ - tor_assert(key_len < INT_MAX); - tor_assert(msg_len < INT_MAX); - tor_assert(hmac_out); - rv = HMAC(EVP_sha256(), key, (int)key_len, (unsigned char*)msg, (int)msg_len, - (unsigned char*)hmac_out, NULL); - tor_assert(rv); -} - -/** Internal state for a eXtendable-Output Function (XOF). */ -struct crypto_xof_t { - keccak_state s; -}; - -/** Allocate a new XOF object backed by SHAKE-256. The security level - * provided is a function of the length of the output used. Read and - * understand FIPS-202 A.2 "Additional Consideration for Extendable-Output - * Functions" before using this construct. - */ -crypto_xof_t * -crypto_xof_new(void) -{ - crypto_xof_t *xof; - xof = tor_malloc(sizeof(crypto_xof_t)); - keccak_xof_init(&xof->s, 256); - return xof; -} - -/** Absorb bytes into a XOF object. Must not be called after a call to - * crypto_xof_squeeze_bytes() for the same instance, and will assert - * if attempted. - */ -void -crypto_xof_add_bytes(crypto_xof_t *xof, const uint8_t *data, size_t len) -{ - int i = keccak_xof_absorb(&xof->s, data, len); - tor_assert(i == 0); -} - -/** Squeeze bytes out of a XOF object. Calling this routine will render - * the XOF instance ineligible to absorb further data. - */ -void -crypto_xof_squeeze_bytes(crypto_xof_t *xof, uint8_t *out, size_t len) -{ - int i = keccak_xof_squeeze(&xof->s, out, len); - tor_assert(i == 0); -} - -/** Cleanse and deallocate a XOF object. */ -void -crypto_xof_free(crypto_xof_t *xof) -{ - if (!xof) - return; - memwipe(xof, 0, sizeof(crypto_xof_t)); - tor_free(xof); -} - -/* 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 - if (!(dh->p = BN_dup(p))) - goto out; - if (!(dh->g = BN_dup(g))) - goto out; -#endif - - /* 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 - 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 - - return res; - err: - /* LCOV_EXCL_START - * This error condition is only reached when an allocation fails */ - 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 - 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 - 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 - - 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)) - 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); -} - -/* random numbers */ - -/** How many bytes of entropy we add at once. - * - * This is how much entropy OpenSSL likes to add right now, so maybe it will - * work for us too. */ -#define ADD_ENTROPY 32 - -/** Set the seed of the weak RNG to a random value. */ -void -crypto_seed_weak_rng(tor_weak_rng_t *rng) -{ - unsigned seed; - crypto_rand((void*)&seed, sizeof(seed)); - tor_init_weak_random(rng, seed); -} - -#ifdef TOR_UNIT_TESTS -int break_strongest_rng_syscall = 0; -int break_strongest_rng_fallback = 0; -#endif - -/** Try to get <b>out_len</b> bytes of the strongest entropy we can generate, - * via system calls, storing it into <b>out</b>. Return 0 on success, -1 on - * failure. A maximum request size of 256 bytes is imposed. - */ -static int -crypto_strongest_rand_syscall(uint8_t *out, size_t out_len) -{ - tor_assert(out_len <= MAX_STRONGEST_RAND_SIZE); - -#ifdef TOR_UNIT_TESTS - if (break_strongest_rng_syscall) - return -1; -#endif - -#if defined(_WIN32) - static int provider_set = 0; - static HCRYPTPROV provider; - - if (!provider_set) { - if (!CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, - CRYPT_VERIFYCONTEXT)) { - log_warn(LD_CRYPTO, "Can't get CryptoAPI provider [1]"); - return -1; - } - provider_set = 1; - } - if (!CryptGenRandom(provider, out_len, out)) { - log_warn(LD_CRYPTO, "Can't get entropy from CryptoAPI."); - return -1; - } - - return 0; -#elif defined(__linux__) && defined(SYS_getrandom) - static int getrandom_works = 1; /* Be optimitic about our chances... */ - - /* getrandom() isn't as straight foward as getentropy(), and has - * no glibc wrapper. - * - * As far as I can tell from getrandom(2) and the source code, the - * requests we issue will always succeed (though it will block on the - * call if /dev/urandom isn't seeded yet), since we are NOT specifying - * GRND_NONBLOCK and the request is <= 256 bytes. - * - * The manpage is unclear on what happens if a signal interrupts the call - * while the request is blocked due to lack of entropy.... - * - * We optimistically assume that getrandom() is available and functional - * because it is the way of the future, and 2 branch mispredicts pale in - * comparision to the overheads involved with failing to open - * /dev/srandom followed by opening and reading from /dev/urandom. - */ - if (PREDICT_LIKELY(getrandom_works)) { - long ret; - /* A flag of '0' here means to read from '/dev/urandom', and to - * block if insufficient entropy is available to service the - * request. - */ - const unsigned int flags = 0; - do { - ret = syscall(SYS_getrandom, out, out_len, flags); - } while (ret == -1 && ((errno == EINTR) ||(errno == EAGAIN))); - - if (PREDICT_UNLIKELY(ret == -1)) { - /* LCOV_EXCL_START we can't actually make the syscall fail in testing. */ - tor_assert(errno != EAGAIN); - tor_assert(errno != EINTR); - - /* Probably ENOSYS. */ - log_warn(LD_CRYPTO, "Can't get entropy from getrandom()."); - getrandom_works = 0; /* Don't bother trying again. */ - return -1; - /* LCOV_EXCL_STOP */ - } - - tor_assert(ret == (long)out_len); - return 0; - } - - return -1; /* getrandom() previously failed unexpectedly. */ -#elif defined(HAVE_GETENTROPY) - /* getentropy() is what Linux's getrandom() wants to be when it grows up. - * the only gotcha is that requests are limited to 256 bytes. - */ - return getentropy(out, out_len); -#else - (void) out; -#endif - - /* This platform doesn't have a supported syscall based random. */ - return -1; -} - -/** Try to get <b>out_len</b> bytes of the strongest entropy we can generate, - * via the per-platform fallback mechanism, storing it into <b>out</b>. - * Return 0 on success, -1 on failure. A maximum request size of 256 bytes - * is imposed. - */ -static int -crypto_strongest_rand_fallback(uint8_t *out, size_t out_len) -{ -#ifdef TOR_UNIT_TESTS - if (break_strongest_rng_fallback) - return -1; -#endif - -#ifdef _WIN32 - /* Windows exclusively uses crypto_strongest_rand_syscall(). */ - (void)out; - (void)out_len; - return -1; -#else - static const char *filenames[] = { - "/dev/srandom", "/dev/urandom", "/dev/random", NULL - }; - int fd, i; - size_t n; - - for (i = 0; filenames[i]; ++i) { - log_debug(LD_FS, "Opening %s for entropy", filenames[i]); - fd = open(sandbox_intern_string(filenames[i]), O_RDONLY, 0); - if (fd<0) continue; - log_info(LD_CRYPTO, "Reading entropy from \"%s\"", filenames[i]); - n = read_all(fd, (char*)out, out_len, 0); - close(fd); - if (n != out_len) { - /* LCOV_EXCL_START - * We can't make /dev/foorandom actually fail. */ - log_warn(LD_CRYPTO, - "Error reading from entropy source (read only %lu bytes).", - (unsigned long)n); - return -1; - /* LCOV_EXCL_STOP */ - } - - return 0; - } - - return -1; -#endif -} - -/** Try to get <b>out_len</b> bytes of the strongest entropy we can generate, - * storing it into <b>out</b>. Return 0 on success, -1 on failure. A maximum - * request size of 256 bytes is imposed. - */ -STATIC int -crypto_strongest_rand_raw(uint8_t *out, size_t out_len) -{ - static const size_t sanity_min_size = 16; - static const int max_attempts = 3; - tor_assert(out_len <= MAX_STRONGEST_RAND_SIZE); - - /* For buffers >= 16 bytes (128 bits), we sanity check the output by - * zero filling the buffer and ensuring that it actually was at least - * partially modified. - * - * Checking that any individual byte is non-zero seems like it would - * fail too often (p = out_len * 1/256) for comfort, but this is an - * "adjust according to taste" sort of check. - */ - memwipe(out, 0, out_len); - for (int i = 0; i < max_attempts; i++) { - /* Try to use the syscall/OS favored mechanism to get strong entropy. */ - if (crypto_strongest_rand_syscall(out, out_len) != 0) { - /* Try to use the less-favored mechanism to get strong entropy. */ - if (crypto_strongest_rand_fallback(out, out_len) != 0) { - /* Welp, we tried. Hopefully the calling code terminates the process - * since we're basically boned without good entropy. - */ - log_warn(LD_CRYPTO, - "Cannot get strong entropy: no entropy source found."); - return -1; - } - } - - if ((out_len < sanity_min_size) || !tor_mem_is_zero((char*)out, out_len)) - return 0; - } - - /* LCOV_EXCL_START - * - * We tried max_attempts times to fill a buffer >= 128 bits long, - * and each time it returned all '0's. Either the system entropy - * source is busted, or the user should go out and buy a ticket to - * every lottery on the planet. - */ - log_warn(LD_CRYPTO, "Strong OS entropy returned all zero buffer."); - - return -1; - /* LCOV_EXCL_STOP */ -} - -/** Try to get <b>out_len</b> bytes of the strongest entropy we can generate, - * storing it into <b>out</b>. - */ -void -crypto_strongest_rand(uint8_t *out, size_t out_len) -{ -#define DLEN SHA512_DIGEST_LENGTH - /* We're going to hash DLEN bytes from the system RNG together with some - * bytes from the openssl PRNG, in order to yield DLEN bytes. - */ - uint8_t inp[DLEN*2]; - uint8_t tmp[DLEN]; - tor_assert(out); - while (out_len) { - crypto_rand((char*) inp, DLEN); - if (crypto_strongest_rand_raw(inp+DLEN, DLEN) < 0) { - // LCOV_EXCL_START - log_err(LD_CRYPTO, "Failed to load strong entropy when generating an " - "important key. Exiting."); - /* Die with an assertion so we get a stack trace. */ - tor_assert(0); - // LCOV_EXCL_STOP - } - if (out_len >= DLEN) { - SHA512(inp, sizeof(inp), out); - out += DLEN; - out_len -= DLEN; - } else { - SHA512(inp, sizeof(inp), tmp); - memcpy(out, tmp, out_len); - break; - } - } - memwipe(tmp, 0, sizeof(tmp)); - memwipe(inp, 0, sizeof(inp)); -#undef DLEN -} - -/** Seed OpenSSL's random number generator with bytes from the operating - * system. Return 0 on success, -1 on failure. - */ -int -crypto_seed_rng(void) -{ - int rand_poll_ok = 0, load_entropy_ok = 0; - uint8_t buf[ADD_ENTROPY]; - - /* OpenSSL has a RAND_poll function that knows about more kinds of - * entropy than we do. We'll try calling that, *and* calling our own entropy - * functions. If one succeeds, we'll accept the RNG as seeded. */ - rand_poll_ok = RAND_poll(); - if (rand_poll_ok == 0) - log_warn(LD_CRYPTO, "RAND_poll() failed."); // LCOV_EXCL_LINE - - load_entropy_ok = !crypto_strongest_rand_raw(buf, sizeof(buf)); - if (load_entropy_ok) { - RAND_seed(buf, sizeof(buf)); - } - - memwipe(buf, 0, sizeof(buf)); - - if ((rand_poll_ok || load_entropy_ok) && RAND_status() == 1) - return 0; - else - return -1; -} - -/** Write <b>n</b> bytes of strong random data to <b>to</b>. Supports mocking - * for unit tests. - * - * This function is not allowed to fail; if it would fail to generate strong - * entropy, it must terminate the process instead. - */ -MOCK_IMPL(void, -crypto_rand, (char *to, size_t n)) -{ - crypto_rand_unmocked(to, n); -} - -/** Write <b>n</b> bytes of strong random data to <b>to</b>. Most callers - * will want crypto_rand instead. - * - * This function is not allowed to fail; if it would fail to generate strong - * entropy, it must terminate the process instead. - */ -void -crypto_rand_unmocked(char *to, size_t n) -{ - int r; - if (n == 0) - return; - - tor_assert(n < INT_MAX); - tor_assert(to); - r = RAND_bytes((unsigned char*)to, (int)n); - /* We consider a PRNG failure non-survivable. Let's assert so that we get a - * stack trace about where it happened. - */ - tor_assert(r >= 0); -} - -/** Return a pseudorandom integer, chosen uniformly from the values - * between 0 and <b>max</b>-1 inclusive. <b>max</b> must be between 1 and - * INT_MAX+1, inclusive. */ -int -crypto_rand_int(unsigned int max) -{ - unsigned int val; - unsigned int cutoff; - tor_assert(max <= ((unsigned int)INT_MAX)+1); - tor_assert(max > 0); /* don't div by 0 */ - - /* We ignore any values that are >= 'cutoff,' to avoid biasing the - * distribution with clipping at the upper end of unsigned int's - * range. - */ - cutoff = UINT_MAX - (UINT_MAX%max); - while (1) { - crypto_rand((char*)&val, sizeof(val)); - if (val < cutoff) - return val % max; - } -} - -/** Return a pseudorandom integer, chosen uniformly from the values i such - * that min <= i < max. - * - * <b>min</b> MUST be in range [0, <b>max</b>). - * <b>max</b> MUST be in range (min, INT_MAX]. - */ -int -crypto_rand_int_range(unsigned int min, unsigned int max) -{ - tor_assert(min < max); - tor_assert(max <= INT_MAX); - - /* The overflow is avoided here because crypto_rand_int() returns a value - * between 0 and (max - min) inclusive. */ - return min + crypto_rand_int(max - min); -} - -/** As crypto_rand_int_range, but supports uint64_t. */ -uint64_t -crypto_rand_uint64_range(uint64_t min, uint64_t max) -{ - tor_assert(min < max); - return min + crypto_rand_uint64(max - min); -} - -/** As crypto_rand_int_range, but supports time_t. */ -time_t -crypto_rand_time_range(time_t min, time_t max) -{ - tor_assert(min < max); - return min + (time_t)crypto_rand_uint64(max - min); -} - -/** Return a pseudorandom 64-bit integer, chosen uniformly from the values - * between 0 and <b>max</b>-1 inclusive. */ -uint64_t -crypto_rand_uint64(uint64_t max) -{ - uint64_t val; - uint64_t cutoff; - tor_assert(max < UINT64_MAX); - tor_assert(max > 0); /* don't div by 0 */ - - /* We ignore any values that are >= 'cutoff,' to avoid biasing the - * distribution with clipping at the upper end of unsigned int's - * range. - */ - cutoff = UINT64_MAX - (UINT64_MAX%max); - while (1) { - crypto_rand((char*)&val, sizeof(val)); - if (val < cutoff) - return val % max; - } -} - -/** Return a pseudorandom double d, chosen uniformly from the range - * 0.0 <= d < 1.0. - */ -double -crypto_rand_double(void) -{ - /* We just use an unsigned int here; we don't really care about getting - * more than 32 bits of resolution */ - unsigned int u; - crypto_rand((char*)&u, sizeof(u)); -#if SIZEOF_INT == 4 -#define UINT_MAX_AS_DOUBLE 4294967296.0 -#elif SIZEOF_INT == 8 -#define UINT_MAX_AS_DOUBLE 1.8446744073709552e+19 -#else -#error SIZEOF_INT is neither 4 nor 8 -#endif - return ((double)u) / UINT_MAX_AS_DOUBLE; -} - -/** Generate and return a new random hostname starting with <b>prefix</b>, - * ending with <b>suffix</b>, and containing no fewer than - * <b>min_rand_len</b> and no more than <b>max_rand_len</b> random base32 - * characters. Does not check for failure. - * - * Clip <b>max_rand_len</b> to MAX_DNS_LABEL_SIZE. - **/ -char * -crypto_random_hostname(int min_rand_len, int max_rand_len, const char *prefix, - const char *suffix) -{ - char *result, *rand_bytes; - int randlen, rand_bytes_len; - size_t resultlen, prefixlen; - - if (max_rand_len > MAX_DNS_LABEL_SIZE) - max_rand_len = MAX_DNS_LABEL_SIZE; - if (min_rand_len > max_rand_len) - min_rand_len = max_rand_len; - - randlen = crypto_rand_int_range(min_rand_len, max_rand_len+1); - - prefixlen = strlen(prefix); - resultlen = prefixlen + strlen(suffix) + randlen + 16; - - rand_bytes_len = ((randlen*5)+7)/8; - if (rand_bytes_len % 5) - rand_bytes_len += 5 - (rand_bytes_len%5); - rand_bytes = tor_malloc(rand_bytes_len); - crypto_rand(rand_bytes, rand_bytes_len); - - result = tor_malloc(resultlen); - memcpy(result, prefix, prefixlen); - base32_encode(result+prefixlen, resultlen-prefixlen, - rand_bytes, rand_bytes_len); - tor_free(rand_bytes); - strlcpy(result+prefixlen+randlen, suffix, resultlen-(prefixlen+randlen)); - - return result; -} - -/** Return a randomly chosen element of <b>sl</b>; or NULL if <b>sl</b> - * is empty. */ -void * -smartlist_choose(const smartlist_t *sl) -{ - int len = smartlist_len(sl); - if (len) - return smartlist_get(sl,crypto_rand_int(len)); - return NULL; /* no elements to choose from */ -} - -/** Scramble the elements of <b>sl</b> into a random order. */ -void -smartlist_shuffle(smartlist_t *sl) -{ - int i; - /* From the end of the list to the front, choose at random from the - positions we haven't looked at yet, and swap that position into the - current position. Remember to give "no swap" the same probability as - any other swap. */ - for (i = smartlist_len(sl)-1; i > 0; --i) { - int j = crypto_rand_int(i+1); - smartlist_swap(sl, i, j); - } -} - -/** - * Destroy the <b>sz</b> bytes of data stored at <b>mem</b>, setting them to - * the value <b>byte</b>. - * If <b>mem</b> is NULL or <b>sz</b> is zero, nothing happens. - * - * This function is preferable to memset, since many compilers will happily - * optimize out memset() when they can convince themselves that the data being - * cleared will never be read. - * - * Right now, our convention is to use this function when we are wiping data - * that's about to become inaccessible, such as stack buffers that are about - * to go out of scope or structures that are about to get freed. (In - * practice, it appears that the compilers we're currently using will optimize - * out the memset()s for stack-allocated buffers, but not those for - * about-to-be-freed structures. That could change, though, so we're being - * wary.) If there are live reads for the data, then you can just use - * memset(). - */ -void -memwipe(void *mem, uint8_t byte, size_t sz) -{ - if (sz == 0) { - return; - } - /* If sz is nonzero, then mem must not be NULL. */ - tor_assert(mem != NULL); - - /* Data this large is likely to be an underflow. */ - tor_assert(sz < SIZE_T_CEILING); - - /* Because whole-program-optimization exists, we may not be able to just - * have this function call "memset". A smart compiler could inline it, then - * eliminate dead memsets, and declare itself to be clever. */ - -#if defined(SecureZeroMemory) || defined(HAVE_SECUREZEROMEMORY) - /* Here's what you do on windows. */ - SecureZeroMemory(mem,sz); -#elif defined(HAVE_RTLSECUREZEROMEMORY) - RtlSecureZeroMemory(mem,sz); -#elif defined(HAVE_EXPLICIT_BZERO) - /* The BSDs provide this. */ - explicit_bzero(mem, sz); -#elif defined(HAVE_MEMSET_S) - /* This is in the C99 standard. */ - memset_s(mem, sz, 0, sz); -#else - /* This is a slow and ugly function from OpenSSL that fills 'mem' with junk - * based on the pointer value, then uses that junk to update a global - * variable. It's an elaborate ruse to trick the compiler into not - * optimizing out the "wipe this memory" code. Read it if you like zany - * programming tricks! In later versions of Tor, we should look for better - * not-optimized-out memory wiping stuff... - * - * ...or maybe not. In practice, there are pure-asm implementations of - * OPENSSL_cleanse() on most platforms, which ought to do the job. - **/ - - OPENSSL_cleanse(mem, sz); -#endif - - /* Just in case some caller of memwipe() is relying on getting a buffer - * filled with a particular value, fill the buffer. - * - * If this function gets inlined, this memset might get eliminated, but - * that's okay: We only care about this particular memset in the case where - * the caller should have been using memset(), and the memset() wouldn't get - * eliminated. In other words, this is here so that we won't break anything - * if somebody accidentally calls memwipe() instead of memset(). - **/ - memset(mem, byte, sz); -} - -#ifndef OPENSSL_THREADS -#error OpenSSL has been built without thread support. Tor requires an \ - OpenSSL library with thread support enabled. -#endif - -#ifndef NEW_THREAD_API -/** Helper: OpenSSL uses this callback to manipulate mutexes. */ -static void -openssl_locking_cb_(int mode, int n, const char *file, int line) -{ - (void)file; - (void)line; - if (!openssl_mutexes_) - /* This is not a really good fix for the - * "release-freed-lock-from-separate-thread-on-shutdown" problem, but - * it can't hurt. */ - return; - if (mode & CRYPTO_LOCK) - tor_mutex_acquire(openssl_mutexes_[n]); - else - tor_mutex_release(openssl_mutexes_[n]); -} - -static void -tor_set_openssl_thread_id(CRYPTO_THREADID *threadid) -{ - CRYPTO_THREADID_set_numeric(threadid, tor_get_thread_id()); -} -#endif - -#if 0 -/* This code is disabled, because OpenSSL never actually uses these callbacks. - */ - -/** OpenSSL helper type: wraps a Tor mutex so that OpenSSL can use it - * as a lock. */ -struct CRYPTO_dynlock_value { - tor_mutex_t *lock; -}; - -/** OpenSSL callback function to allocate a lock: see CRYPTO_set_dynlock_* - * documentation in OpenSSL's docs for more info. */ -static struct CRYPTO_dynlock_value * -openssl_dynlock_create_cb_(const char *file, int line) -{ - struct CRYPTO_dynlock_value *v; - (void)file; - (void)line; - v = tor_malloc(sizeof(struct CRYPTO_dynlock_value)); - v->lock = tor_mutex_new(); - return v; -} - -/** OpenSSL callback function to acquire or release a lock: see - * CRYPTO_set_dynlock_* documentation in OpenSSL's docs for more info. */ -static void -openssl_dynlock_lock_cb_(int mode, struct CRYPTO_dynlock_value *v, - const char *file, int line) -{ - (void)file; - (void)line; - if (mode & CRYPTO_LOCK) - tor_mutex_acquire(v->lock); - else - tor_mutex_release(v->lock); -} - -/** OpenSSL callback function to free a lock: see CRYPTO_set_dynlock_* - * documentation in OpenSSL's docs for more info. */ -static void -openssl_dynlock_destroy_cb_(struct CRYPTO_dynlock_value *v, - const char *file, int line) -{ - (void)file; - (void)line; - tor_mutex_free(v->lock); - tor_free(v); -} -#endif - -/** @{ */ -/** Helper: Construct mutexes, and set callbacks to help OpenSSL handle being - * multithreaded. Returns 0. */ -static int -setup_openssl_threading(void) -{ -#ifndef NEW_THREAD_API - int i; - int n = CRYPTO_num_locks(); - n_openssl_mutexes_ = n; - openssl_mutexes_ = tor_calloc(n, sizeof(tor_mutex_t *)); - for (i=0; i < n; ++i) - openssl_mutexes_[i] = tor_mutex_new(); - CRYPTO_set_locking_callback(openssl_locking_cb_); - CRYPTO_THREADID_set_callback(tor_set_openssl_thread_id); -#endif -#if 0 - CRYPTO_set_dynlock_create_callback(openssl_dynlock_create_cb_); - CRYPTO_set_dynlock_lock_callback(openssl_dynlock_lock_cb_); - CRYPTO_set_dynlock_destroy_callback(openssl_dynlock_destroy_cb_); -#endif - return 0; -} - -/** Uninitialize the crypto library. Return 0 on success. Does not detect - * failure. - */ -int -crypto_global_cleanup(void) -{ - EVP_cleanup(); -#ifndef NEW_THREAD_API - ERR_remove_thread_state(NULL); -#endif - ERR_free_strings(); - - 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); - -#ifndef DISABLE_ENGINES - ENGINE_cleanup(); -#endif - - CONF_modules_unload(1); - CRYPTO_cleanup_all_ex_data(); - -#ifndef NEW_THREAD_API - if (n_openssl_mutexes_) { - int n = n_openssl_mutexes_; - tor_mutex_t **ms = openssl_mutexes_; - int i; - openssl_mutexes_ = NULL; - n_openssl_mutexes_ = 0; - for (i=0;i<n;++i) { - tor_mutex_free(ms[i]); - } - tor_free(ms); - } -#endif - - tor_free(crypto_openssl_version_str); - tor_free(crypto_openssl_header_version_str); - return 0; -} - -/** @} */ - |