diff options
Diffstat (limited to 'src/lib/tls/x509_openssl.c')
| -rw-r--r-- | src/lib/tls/x509_openssl.c | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/src/lib/tls/x509_openssl.c b/src/lib/tls/x509_openssl.c new file mode 100644 index 0000000000..c003d4704b --- /dev/null +++ b/src/lib/tls/x509_openssl.c @@ -0,0 +1,489 @@ +/* Copyright (c) 2003, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2018, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file x509_openssl.c + * \brief Wrapper functions to present a consistent interface to + * X.509 functions from OpenSSL. + **/ + +#define TOR_X509_PRIVATE +#include "lib/tls/x509.h" +#include "lib/tls/tortls.h" +#include "lib/crypt_ops/crypto_rand.h" +#include "lib/crypt_ops/crypto_util.h" +#include "lib/crypt_ops/compat_openssl.h" + +/* Some versions of OpenSSL declare SSL_get_selected_srtp_profile twice in + * srtp.h. Suppress the GCC warning so we can build with -Wredundant-decl. */ +DISABLE_GCC_WARNING(redundant-decls) + +#include <openssl/opensslv.h> + +#ifdef OPENSSL_NO_EC +#error "We require OpenSSL with ECC support" +#endif + +#include <openssl/err.h> +#include <openssl/asn1.h> +#include <openssl/bio.h> +#include <openssl/bn.h> +#include <openssl/rsa.h> + +ENABLE_GCC_WARNING(redundant-decls) + +#include "lib/log/log.h" +#include "lib/log/util_bug.h" +#include "lib/ctime/di_ops.h" +#include "lib/encoding/time_fmt.h" + +#include <stdlib.h> +#include <string.h> + +#ifdef OPENSSL_1_1_API +#define X509_get_notBefore_const(cert) \ + X509_get0_notBefore(cert) +#define X509_get_notAfter_const(cert) \ + X509_get0_notAfter(cert) +#ifndef X509_get_notBefore +#define X509_get_notBefore(cert) \ + X509_getm_notBefore(cert) +#endif +#ifndef X509_get_notAfter +#define X509_get_notAfter(cert) \ + X509_getm_notAfter(cert) +#endif +#else /* ! OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,0) */ +#define X509_get_notBefore_const(cert) \ + ((const ASN1_TIME*) X509_get_notBefore((X509 *)cert)) +#define X509_get_notAfter_const(cert) \ + ((const ASN1_TIME*) X509_get_notAfter((X509 *)cert)) +#endif + +/** Return a newly allocated X509 name with commonName <b>cname</b>. */ +static X509_NAME * +tor_x509_name_new(const char *cname) +{ + int nid; + X509_NAME *name; + /* LCOV_EXCL_BR_START : these branches will only fail on OOM errors */ + if (!(name = X509_NAME_new())) + return NULL; + if ((nid = OBJ_txt2nid("commonName")) == NID_undef) goto error; + if (!(X509_NAME_add_entry_by_NID(name, nid, MBSTRING_ASC, + (unsigned char*)cname, -1, -1, 0))) + goto error; + /* LCOV_EXCL_BR_STOP */ + return name; + + /* LCOV_EXCL_START : these lines will only execute on out of memory errors*/ + error: + X509_NAME_free(name); + return NULL; + /* LCOV_EXCL_STOP */ +} + +/** Generate and sign an X509 certificate with the public key <b>rsa</b>, + * signed by the private key <b>rsa_sign</b>. The commonName of the + * certificate will be <b>cname</b>; the commonName of the issuer will be + * <b>cname_sign</b>. The cert will be valid for <b>cert_lifetime</b> + * seconds, starting from some time in the past. + * + * Return a certificate on success, NULL on failure. + */ +MOCK_IMPL(X509 *, +tor_tls_create_certificate,(crypto_pk_t *rsa, + crypto_pk_t *rsa_sign, + const char *cname, + const char *cname_sign, + unsigned int cert_lifetime)) +{ + /* OpenSSL generates self-signed certificates with random 64-bit serial + * numbers, so let's do that too. */ +#define SERIAL_NUMBER_SIZE 8 + + time_t start_time, end_time; + BIGNUM *serial_number = NULL; + unsigned char serial_tmp[SERIAL_NUMBER_SIZE]; + EVP_PKEY *sign_pkey = NULL, *pkey=NULL; + X509 *x509 = NULL; + X509_NAME *name = NULL, *name_issuer=NULL; + + tor_tls_init(); + + time_t now = time(NULL); + + tor_tls_pick_certificate_lifetime(now, cert_lifetime, + &start_time, &end_time); + + tor_assert(rsa); + tor_assert(cname); + tor_assert(rsa_sign); + tor_assert(cname_sign); + if (!(sign_pkey = crypto_pk_get_openssl_evp_pkey_(rsa_sign,1))) + goto error; + if (!(pkey = crypto_pk_get_openssl_evp_pkey_(rsa,0))) + goto error; + if (!(x509 = X509_new())) + goto error; + if (!(X509_set_version(x509, 2))) + goto error; + + { /* our serial number is 8 random bytes. */ + crypto_rand((char *)serial_tmp, sizeof(serial_tmp)); + if (!(serial_number = BN_bin2bn(serial_tmp, sizeof(serial_tmp), NULL))) + goto error; + if (!(BN_to_ASN1_INTEGER(serial_number, X509_get_serialNumber(x509)))) + goto error; + } + + if (!(name = tor_x509_name_new(cname))) + goto error; + if (!(X509_set_subject_name(x509, name))) + goto error; + if (!(name_issuer = tor_x509_name_new(cname_sign))) + goto error; + if (!(X509_set_issuer_name(x509, name_issuer))) + goto error; + + if (!X509_time_adj(X509_get_notBefore(x509),0,&start_time)) + goto error; + if (!X509_time_adj(X509_get_notAfter(x509),0,&end_time)) + goto error; + if (!X509_set_pubkey(x509, pkey)) + goto error; + + if (!X509_sign(x509, sign_pkey, EVP_sha256())) + goto error; + + goto done; + error: + if (x509) { + X509_free(x509); + x509 = NULL; + } + done: + tls_log_errors(NULL, LOG_WARN, LD_NET, "generating certificate"); + if (sign_pkey) + EVP_PKEY_free(sign_pkey); + if (pkey) + EVP_PKEY_free(pkey); + if (serial_number) + BN_clear_free(serial_number); + if (name) + X509_NAME_free(name); + if (name_issuer) + X509_NAME_free(name_issuer); + return x509; + +#undef SERIAL_NUMBER_SIZE +} + +/** Free all storage held in <b>cert</b> */ +void +tor_x509_cert_free_(tor_x509_cert_t *cert) +{ + if (! cert) + return; + if (cert->cert) + X509_free(cert->cert); + tor_free(cert->encoded); + memwipe(cert, 0x03, sizeof(*cert)); + /* LCOV_EXCL_BR_START since cert will never be NULL here */ + tor_free(cert); + /* LCOV_EXCL_BR_STOP */ +} + +/** + * Allocate a new tor_x509_cert_t to hold the certificate "x509_cert". + * + * Steals a reference to x509_cert. + */ +MOCK_IMPL(tor_x509_cert_t *, +tor_x509_cert_new,(X509 *x509_cert)) +{ + tor_x509_cert_t *cert; + EVP_PKEY *pkey; + RSA *rsa; + int length; + unsigned char *buf = NULL; + + if (!x509_cert) + return NULL; + + length = i2d_X509(x509_cert, &buf); + cert = tor_malloc_zero(sizeof(tor_x509_cert_t)); + if (length <= 0 || buf == NULL) { + goto err; + } + cert->encoded_len = (size_t) length; + cert->encoded = tor_malloc(length); + memcpy(cert->encoded, buf, length); + OPENSSL_free(buf); + + cert->cert = x509_cert; + + crypto_common_digests(&cert->cert_digests, + (char*)cert->encoded, cert->encoded_len); + + if ((pkey = X509_get_pubkey(x509_cert)) && + (rsa = EVP_PKEY_get1_RSA(pkey))) { + crypto_pk_t *pk = crypto_new_pk_from_openssl_rsa_(rsa); + if (crypto_pk_get_common_digests(pk, &cert->pkey_digests) < 0) { + crypto_pk_free(pk); + EVP_PKEY_free(pkey); + goto err; + } + + cert->pkey_digests_set = 1; + crypto_pk_free(pk); + EVP_PKEY_free(pkey); + } + + return cert; + err: + /* LCOV_EXCL_START for the same reason as the exclusion above */ + tor_free(cert); + log_err(LD_CRYPTO, "Couldn't wrap encoded X509 certificate."); + X509_free(x509_cert); + return NULL; + /* LCOV_EXCL_STOP */ +} + +/** Return a new copy of <b>cert</b>. */ +tor_x509_cert_t * +tor_x509_cert_dup(const tor_x509_cert_t *cert) +{ + tor_assert(cert); + X509 *x509 = cert->cert; + return tor_x509_cert_new(X509_dup(x509)); +} + +/** Read a DER-encoded X509 cert, of length exactly <b>certificate_len</b>, + * from a <b>certificate</b>. Return a newly allocated tor_x509_cert_t on + * success and NULL on failure. */ +tor_x509_cert_t * +tor_x509_cert_decode(const uint8_t *certificate, size_t certificate_len) +{ + X509 *x509; + const unsigned char *cp = (const unsigned char *)certificate; + tor_x509_cert_t *newcert; + tor_assert(certificate); + check_no_tls_errors(); + + if (certificate_len > INT_MAX) + goto err; + + x509 = d2i_X509(NULL, &cp, (int)certificate_len); + + if (!x509) + goto err; /* Couldn't decode */ + if (cp - certificate != (int)certificate_len) { + X509_free(x509); + goto err; /* Didn't use all the bytes */ + } + newcert = tor_x509_cert_new(x509); + if (!newcert) { + goto err; + } + if (newcert->encoded_len != certificate_len || + fast_memneq(newcert->encoded, certificate, certificate_len)) { + /* Cert wasn't in DER */ + tor_x509_cert_free(newcert); + goto err; + } + return newcert; + err: + tls_log_errors(NULL, LOG_INFO, LD_CRYPTO, "decoding a certificate"); + return NULL; +} + +/** + * Return a newly allocated copy of the public key that a certificate + * certifies. Watch out! This returns NULL if the cert's key is not RSA. + */ +crypto_pk_t * +tor_tls_cert_get_key(tor_x509_cert_t *cert) +{ + crypto_pk_t *result = NULL; + EVP_PKEY *pkey = X509_get_pubkey(cert->cert); + RSA *rsa; + if (!pkey) + return NULL; + rsa = EVP_PKEY_get1_RSA(pkey); + if (!rsa) { + EVP_PKEY_free(pkey); + return NULL; + } + result = crypto_new_pk_from_openssl_rsa_(rsa); + EVP_PKEY_free(pkey); + return result; +} + +/** Check whether <b>cert</b> is well-formed, currently live, and correctly + * signed by the public key in <b>signing_cert</b>. If <b>check_rsa_1024</b>, + * make sure that it has an RSA key with 1024 bits; otherwise, just check that + * the key is long enough. Return 1 if the cert is good, and 0 if it's bad or + * we couldn't check it. */ +int +tor_tls_cert_is_valid(int severity, + const tor_x509_cert_t *cert, + const tor_x509_cert_t *signing_cert, + time_t now, + int check_rsa_1024) +{ + check_no_tls_errors(); + EVP_PKEY *cert_key; + int r, key_ok = 0; + + if (!signing_cert || !cert) + goto bad; + + EVP_PKEY *signing_key = X509_get_pubkey(signing_cert->cert); + if (!signing_key) + goto bad; + r = X509_verify(cert->cert, signing_key); + EVP_PKEY_free(signing_key); + if (r <= 0) + goto bad; + + /* okay, the signature checked out right. Now let's check the check the + * lifetime. */ + if (tor_x509_check_cert_lifetime_internal(severity, cert->cert, now, + 48*60*60, 30*24*60*60) < 0) + goto bad; + + cert_key = X509_get_pubkey(cert->cert); + if (check_rsa_1024 && cert_key) { + RSA *rsa = EVP_PKEY_get1_RSA(cert_key); +#ifdef OPENSSL_1_1_API + if (rsa && RSA_bits(rsa) == 1024) +#else + if (rsa && BN_num_bits(rsa->n) == 1024) +#endif + key_ok = 1; + if (rsa) + RSA_free(rsa); + } else if (cert_key) { + int min_bits = 1024; +#ifdef EVP_PKEY_EC + if (EVP_PKEY_base_id(cert_key) == EVP_PKEY_EC) + min_bits = 128; +#endif + if (EVP_PKEY_bits(cert_key) >= min_bits) + key_ok = 1; + } + EVP_PKEY_free(cert_key); + if (!key_ok) + goto bad; + + /* XXXX compare DNs or anything? */ + + return 1; + bad: + tls_log_errors(NULL, LOG_INFO, LD_CRYPTO, "checking a certificate"); + return 0; +} + +/** Warn that a certificate lifetime extends through a certain range. */ +static void +log_cert_lifetime(int severity, const X509 *cert, const char *problem, + time_t now) +{ + BIO *bio = NULL; + BUF_MEM *buf; + char *s1=NULL, *s2=NULL; + char mytime[33]; + struct tm tm; + size_t n; + + if (problem) + tor_log(severity, LD_GENERAL, + "Certificate %s. Either their clock is set wrong, or your clock " + "is wrong.", + problem); + + if (!(bio = BIO_new(BIO_s_mem()))) { + log_warn(LD_GENERAL, "Couldn't allocate BIO!"); goto end; + } + if (!(ASN1_TIME_print(bio, X509_get_notBefore_const(cert)))) { + tls_log_errors(NULL, LOG_WARN, LD_NET, "printing certificate lifetime"); + goto end; + } + BIO_get_mem_ptr(bio, &buf); + s1 = tor_strndup(buf->data, buf->length); + + (void)BIO_reset(bio); + if (!(ASN1_TIME_print(bio, X509_get_notAfter_const(cert)))) { + tls_log_errors(NULL, LOG_WARN, LD_NET, "printing certificate lifetime"); + goto end; + } + BIO_get_mem_ptr(bio, &buf); + s2 = tor_strndup(buf->data, buf->length); + + n = strftime(mytime, 32, "%b %d %H:%M:%S %Y UTC", tor_gmtime_r(&now, &tm)); + if (n > 0) { + tor_log(severity, LD_GENERAL, + "(certificate lifetime runs from %s through %s. Your time is %s.)", + s1,s2,mytime); + } else { + tor_log(severity, LD_GENERAL, + "(certificate lifetime runs from %s through %s. " + "Couldn't get your time.)", + s1, s2); + } + + end: + /* Not expected to get invoked */ + tls_log_errors(NULL, LOG_WARN, LD_NET, "getting certificate lifetime"); + if (bio) + BIO_free(bio); + tor_free(s1); + tor_free(s2); +} + +/** Helper: check whether <b>cert</b> is expired give or take + * <b>past_tolerance</b> seconds, or not-yet-valid give or take + * <b>future_tolerance</b> seconds. (Relative to the current time + * <b>now</b>.) If it is live, return 0. If it is not live, log a message + * and return -1. */ +int +tor_x509_check_cert_lifetime_internal(int severity, const X509 *cert, + time_t now, + int past_tolerance, int future_tolerance) +{ + time_t t; + + t = now + future_tolerance; + if (X509_cmp_time(X509_get_notBefore_const(cert), &t) > 0) { + log_cert_lifetime(severity, cert, "not yet valid", now); + return -1; + } + t = now - past_tolerance; + if (X509_cmp_time(X509_get_notAfter_const(cert), &t) < 0) { + log_cert_lifetime(severity, cert, "already expired", now); + return -1; + } + + return 0; +} + +#ifdef TOR_UNIT_TESTS +/* Testing only: return a new x509 cert with the same contents as <b>inp</b>, + but with the expiration time <b>new_expiration_time</b>, signed with + <b>signing_key</b>. */ +STATIC tor_x509_cert_t * +tor_x509_cert_replace_expiration(const tor_x509_cert_t *inp, + time_t new_expiration_time, + crypto_pk_t *signing_key) +{ + X509 *newc = X509_dup(inp->cert); + X509_time_adj(X509_get_notAfter(newc), 0, &new_expiration_time); + EVP_PKEY *pk = crypto_pk_get_openssl_evp_pkey_(signing_key, 1); + tor_assert(X509_sign(newc, pk, EVP_sha256())); + EVP_PKEY_free(pk); + return tor_x509_cert_new(newc); +} +#endif /* defined(TOR_UNIT_TESTS) */ |