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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
#include "crypto/s2n_libcrypto.h"
#include <openssl/crypto.h>
#include <openssl/opensslv.h>
#include "crypto/s2n_crypto.h"
#include "crypto/s2n_fips.h"
#include "crypto/s2n_openssl.h"
#include "utils/s2n_safety.h"
#include "utils/s2n_safety_macros.h"
#if S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
#error #include <openssl/provider.h>
#endif
#include <string.h>
/* Note: OpenSSL 1.0.2 -> 1.1.0 implemented a new API to get the version number
* and version name. We have to handle that by using old functions
* (named "SSLea*"). Newer version of OpenSSL luckily define these symbols to
* the new API. When dropping OpenSSL 1.0.2 support, we can move to the new API.
*/
/* The result of SSLeay_version(SSLEAY_VERSION) for OpenSSL and AWS-LC depends on the
* version. AWS-LC and BoringSSL have consistent prefixes that can be statically asserted.
*
* https://github.com/awslabs/aws-lc/commit/8f184f5d69604cc4645bafec47c2d6d9929cb50f
* has not been pushed to the fips branch of AWS-LC. In addition, we can't
* distinguish AWS-LC fips and non-fips at pre-processing time since AWS-LC
* doesn't distribute fips-specific header files.
*/
#define EXPECTED_AWSLC_VERSION_PREFIX_FIPS_OR_OLD "BoringSSL"
#define EXPECTED_AWSLC_VERSION_PREFIX_NON_FIPS "AWS-LC"
#define EXPECTED_BORINGSSL_VERSION_PREFIX "BoringSSL"
/* https://www.openssl.org/docs/man{1.0.2, 1.1.1, 3.0}/man3/OPENSSL_VERSION_NUMBER.html
* OPENSSL_VERSION_NUMBER in hex is: MNNFFPPS major minor fix patch status.
* Bitwise: MMMMNNNNNNNNFFFFFFFFPPPPPPPPSSSS
* To not be overly restrictive, we only care about the major version.
* From OpenSSL 3.0 the "fix" part is also deprecated and is always a flat 0x00.
*/
#define VERSION_NUMBER_MASK 0xF0000000L
/* Returns the version name of the libcrypto containing the definition that the
* symbol OpenSSL_version binded to at link-time. This can be used as
* verification at run-time that s2n linked against the expected libcrypto.
*/
static const char *s2n_libcrypto_get_version_name(void)
{
return SSLeay_version(SSLEAY_VERSION);
}
static S2N_RESULT s2n_libcrypto_validate_expected_version_prefix(const char *expected_name_prefix)
{
RESULT_ENSURE_REF(expected_name_prefix);
RESULT_ENSURE_REF(s2n_libcrypto_get_version_name());
RESULT_ENSURE_LTE(strlen(expected_name_prefix), strlen(s2n_libcrypto_get_version_name()));
RESULT_ENSURE(s2n_constant_time_equals((const uint8_t *) expected_name_prefix, (const uint8_t *) s2n_libcrypto_get_version_name(), (const uint32_t) strlen(expected_name_prefix)), S2N_ERR_LIBCRYPTO_VERSION_NAME_MISMATCH);
return S2N_RESULT_OK;
}
/* Compare compile-time version number with the version number of the libcrypto
* containing the definition that the symbol OpenSSL_version_num binded to at
* link-time.
*
* This is an imperfect check for AWS-LC and BoringSSL, since their version
* number is basically never incremented. However, for these we have a strong
* check through s2n_libcrypto_validate_expected_version_name(), so it is not
* of great importance.
*/
static S2N_RESULT s2n_libcrypto_validate_expected_version_number(void)
{
/* We mutate the version number in s2n_openssl.h when detecting Libressl. This
* value is cached by s2n_get_openssl_version(). Hence, for libressl, the
* run-time version number will always be different from what
* s2n_get_openssl_version() returns. We cater for this here by just getting
* what ever we cached instead of asking Libressl libcrypto.
*/
#if defined(LIBRESSL_VERSION_NUMBER)
unsigned long run_time_version_number = s2n_get_openssl_version() & VERSION_NUMBER_MASK;
#else
unsigned long run_time_version_number = SSLeay() & VERSION_NUMBER_MASK;
#endif
unsigned long compile_time_version_number = s2n_get_openssl_version() & VERSION_NUMBER_MASK;
RESULT_ENSURE(compile_time_version_number == run_time_version_number, S2N_ERR_LIBCRYPTO_VERSION_NUMBER_MISMATCH);
return S2N_RESULT_OK;
}
/* s2n_libcrypto_is_*() encodes the libcrypto version used at build-time.
* Currently only captures AWS-LC and BoringSSL. When a libcrypto-dependent
* branch is required, we prefer these functions where possible to reduce
# #ifs and avoid potential bugs where the header containing the #define is not
* included.
*/
#if defined(OPENSSL_IS_AWSLC) && defined(OPENSSL_IS_BORINGSSL)
#error "Both OPENSSL_IS_AWSLC and OPENSSL_IS_BORINGSSL are defined at the same time!"
#endif
bool s2n_libcrypto_is_awslc()
{
#if defined(OPENSSL_IS_AWSLC)
return true;
#else
return false;
#endif
}
static uint64_t s2n_libcrypto_awslc_api_version(void)
{
#if defined(OPENSSL_IS_AWSLC)
return AWSLC_API_VERSION;
#else
return 0;
#endif
}
bool s2n_libcrypto_is_boringssl()
{
#if defined(OPENSSL_IS_BORINGSSL)
return true;
#else
return false;
#endif
}
S2N_RESULT s2n_libcrypto_init(void)
{
#if S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
RESULT_ENSURE(OSSL_PROVIDER_load(NULL, "default") != NULL, S2N_ERR_OSSL_PROVIDER);
#ifdef S2N_LIBCRYPTO_SUPPORTS_EVP_RC4
/* needed to support RC4 algorithm
* https://www.openssl.org/docs/man3.0/man7/OSSL_PROVIDER-legacy.html
*/
RESULT_ENSURE(OSSL_PROVIDER_load(NULL, "legacy") != NULL, S2N_ERR_OSSL_PROVIDER);
#endif
#endif
return S2N_RESULT_OK;
}
#if S2N_OPENSSL_VERSION_AT_LEAST(3, 0, 0)
int s2n_libcrypto_cleanup_cb(OSSL_PROVIDER *provider, void *cbdata)
{
return OSSL_PROVIDER_unload(provider);
}
S2N_RESULT s2n_libcrypto_cleanup(void)
{
RESULT_GUARD_OSSL(OSSL_PROVIDER_do_all(NULL, *s2n_libcrypto_cleanup_cb, NULL), S2N_ERR_ATEXIT);
return S2N_RESULT_OK;
}
#else
S2N_RESULT s2n_libcrypto_cleanup(void)
{
return S2N_RESULT_OK;
}
#endif
/* Performs various checks to validate that the libcrypto used at compile-time
* is the same libcrypto being used at run-time.
*/
S2N_RESULT s2n_libcrypto_validate_runtime(void)
{
/* Sanity check that we don't think we built against AWS-LC and BoringSSL at
* the same time.
*/
RESULT_ENSURE_EQ(s2n_libcrypto_is_boringssl() && s2n_libcrypto_is_awslc(), false);
/* If we know the expected version name, we can validate it. */
if (s2n_libcrypto_is_awslc()) {
const char *expected_awslc_name_prefix = NULL;
/* For backwards compatability, also check the AWS-LC API version see
* https://github.com/awslabs/aws-lc/pull/467. When we are confident we
* don't meet anymore "old" AWS-LC libcrypto's, this API version check
* can be removed.
*/
if (s2n_libcrypto_is_fips() || s2n_libcrypto_awslc_api_version() < 17) {
expected_awslc_name_prefix = EXPECTED_AWSLC_VERSION_PREFIX_FIPS_OR_OLD;
} else {
expected_awslc_name_prefix = EXPECTED_AWSLC_VERSION_PREFIX_NON_FIPS;
}
RESULT_GUARD(s2n_libcrypto_validate_expected_version_prefix(expected_awslc_name_prefix));
} else if (s2n_libcrypto_is_boringssl()) {
RESULT_GUARD(s2n_libcrypto_validate_expected_version_prefix(EXPECTED_BORINGSSL_VERSION_PREFIX));
}
RESULT_GUARD(s2n_libcrypto_validate_expected_version_number());
return S2N_RESULT_OK;
}
bool s2n_libcrypto_is_interned(void)
{
#if defined(S2N_INTERN_LIBCRYPTO)
return true;
#else
return false;
#endif
}
unsigned long s2n_get_openssl_version(void)
{
return OPENSSL_VERSION_NUMBER;
}
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