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ssl_tls13_generic.c
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ssl_tls13_generic.c
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/*
* TLS 1.3 functionality shared between client and server
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "common.h"
#if defined(MBEDTLS_SSL_TLS_C) && defined(MBEDTLS_SSL_PROTO_TLS1_3)
#include <string.h>
#include "mbedtls/error.h"
#include "debug_internal.h"
#include "mbedtls/oid.h"
#include "mbedtls/platform.h"
#include "mbedtls/constant_time.h"
#include "psa/crypto.h"
#include "mbedtls/psa_util.h"
#include "ssl_misc.h"
#include "ssl_tls13_invasive.h"
#include "ssl_tls13_keys.h"
#include "ssl_debug_helpers.h"
#include "psa/crypto.h"
#include "psa_util_internal.h"
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_EPHEMERAL_ENABLED)
/* Define a local translating function to save code size by not using too many
* arguments in each translating place. */
static int local_err_translation(psa_status_t status)
{
return psa_status_to_mbedtls(status, psa_to_ssl_errors,
ARRAY_LENGTH(psa_to_ssl_errors),
psa_generic_status_to_mbedtls);
}
#define PSA_TO_MBEDTLS_ERR(status) local_err_translation(status)
#endif
const uint8_t mbedtls_ssl_tls13_hello_retry_request_magic[
MBEDTLS_SERVER_HELLO_RANDOM_LEN] =
{ 0xCF, 0x21, 0xAD, 0x74, 0xE5, 0x9A, 0x61, 0x11,
0xBE, 0x1D, 0x8C, 0x02, 0x1E, 0x65, 0xB8, 0x91,
0xC2, 0xA2, 0x11, 0x16, 0x7A, 0xBB, 0x8C, 0x5E,
0x07, 0x9E, 0x09, 0xE2, 0xC8, 0xA8, 0x33, 0x9C };
int mbedtls_ssl_tls13_fetch_handshake_msg(mbedtls_ssl_context *ssl,
unsigned hs_type,
unsigned char **buf,
size_t *buf_len)
{
int ret;
if ((ret = mbedtls_ssl_read_record(ssl, 0)) != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_read_record", ret);
goto cleanup;
}
if (ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
ssl->in_msg[0] != hs_type) {
MBEDTLS_SSL_DEBUG_MSG(1, ("Receive unexpected handshake message."));
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE);
ret = MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE;
goto cleanup;
}
/*
* Jump handshake header (4 bytes, see Section 4 of RFC 8446).
* ...
* HandshakeType msg_type;
* uint24 length;
* ...
*/
*buf = ssl->in_msg + 4;
*buf_len = ssl->in_hslen - 4;
cleanup:
return ret;
}
int mbedtls_ssl_tls13_is_supported_versions_ext_present_in_exts(
mbedtls_ssl_context *ssl,
const unsigned char *buf, const unsigned char *end,
const unsigned char **supported_versions_data,
const unsigned char **supported_versions_data_end)
{
const unsigned char *p = buf;
size_t extensions_len;
const unsigned char *extensions_end;
*supported_versions_data = NULL;
*supported_versions_data_end = NULL;
/* Case of no extension */
if (p == end) {
return 0;
}
/* ...
* Extension extensions<x..2^16-1>;
* ...
* struct {
* ExtensionType extension_type; (2 bytes)
* opaque extension_data<0..2^16-1>;
* } Extension;
*/
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
extensions_len = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2;
/* Check extensions do not go beyond the buffer of data. */
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, extensions_len);
extensions_end = p + extensions_len;
while (p < extensions_end) {
unsigned int extension_type;
size_t extension_data_len;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4);
extension_type = MBEDTLS_GET_UINT16_BE(p, 0);
extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2);
p += 4;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len);
if (extension_type == MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS) {
*supported_versions_data = p;
*supported_versions_data_end = p + extension_data_len;
return 1;
}
p += extension_data_len;
}
return 0;
}
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
/*
* STATE HANDLING: Read CertificateVerify
*/
/* Macro to express the maximum length of the verify structure.
*
* The structure is computed per TLS 1.3 specification as:
* - 64 bytes of octet 32,
* - 33 bytes for the context string
* (which is either "TLS 1.3, client CertificateVerify"
* or "TLS 1.3, server CertificateVerify"),
* - 1 byte for the octet 0x0, which serves as a separator,
* - 32 or 48 bytes for the Transcript-Hash(Handshake Context, Certificate)
* (depending on the size of the transcript_hash)
*
* This results in a total size of
* - 130 bytes for a SHA256-based transcript hash, or
* (64 + 33 + 1 + 32 bytes)
* - 146 bytes for a SHA384-based transcript hash.
* (64 + 33 + 1 + 48 bytes)
*
*/
#define SSL_VERIFY_STRUCT_MAX_SIZE (64 + \
33 + \
1 + \
MBEDTLS_TLS1_3_MD_MAX_SIZE \
)
/*
* The ssl_tls13_create_verify_structure() creates the verify structure.
* As input, it requires the transcript hash.
*
* The caller has to ensure that the buffer has size at least
* SSL_VERIFY_STRUCT_MAX_SIZE bytes.
*/
static void ssl_tls13_create_verify_structure(const unsigned char *transcript_hash,
size_t transcript_hash_len,
unsigned char *verify_buffer,
size_t *verify_buffer_len,
int from)
{
size_t idx;
/* RFC 8446, Section 4.4.3:
*
* The digital signature [in the CertificateVerify message] is then
* computed over the concatenation of:
* - A string that consists of octet 32 (0x20) repeated 64 times
* - The context string
* - A single 0 byte which serves as the separator
* - The content to be signed
*/
memset(verify_buffer, 0x20, 64);
idx = 64;
if (from == MBEDTLS_SSL_IS_CLIENT) {
memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(client_cv));
idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(client_cv);
} else { /* from == MBEDTLS_SSL_IS_SERVER */
memcpy(verify_buffer + idx, MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN(server_cv));
idx += MBEDTLS_SSL_TLS1_3_LBL_LEN(server_cv);
}
verify_buffer[idx++] = 0x0;
memcpy(verify_buffer + idx, transcript_hash, transcript_hash_len);
idx += transcript_hash_len;
*verify_buffer_len = idx;
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_parse_certificate_verify(mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end,
const unsigned char *verify_buffer,
size_t verify_buffer_len)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
const unsigned char *p = buf;
uint16_t algorithm;
size_t signature_len;
mbedtls_pk_type_t sig_alg;
mbedtls_md_type_t md_alg;
psa_algorithm_t hash_alg = PSA_ALG_NONE;
unsigned char verify_hash[PSA_HASH_MAX_SIZE];
size_t verify_hash_len;
void const *options = NULL;
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
mbedtls_pk_rsassa_pss_options rsassa_pss_options;
#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
/*
* struct {
* SignatureScheme algorithm;
* opaque signature<0..2^16-1>;
* } CertificateVerify;
*/
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
algorithm = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2;
/* RFC 8446 section 4.4.3
*
* If the CertificateVerify message is sent by a server, the signature
* algorithm MUST be one offered in the client's "signature_algorithms"
* extension unless no valid certificate chain can be produced without
* unsupported algorithms
*
* RFC 8446 section 4.4.2.2
*
* If the client cannot construct an acceptable chain using the provided
* certificates and decides to abort the handshake, then it MUST abort the
* handshake with an appropriate certificate-related alert
* (by default, "unsupported_certificate").
*
* Check if algorithm is an offered signature algorithm.
*/
if (!mbedtls_ssl_sig_alg_is_offered(ssl, algorithm)) {
/* algorithm not in offered signature algorithms list */
MBEDTLS_SSL_DEBUG_MSG(1, ("Received signature algorithm(%04x) is not "
"offered.",
(unsigned int) algorithm));
goto error;
}
if (mbedtls_ssl_get_pk_type_and_md_alg_from_sig_alg(
algorithm, &sig_alg, &md_alg) != 0) {
goto error;
}
hash_alg = mbedtls_md_psa_alg_from_type(md_alg);
if (hash_alg == 0) {
goto error;
}
MBEDTLS_SSL_DEBUG_MSG(3, ("Certificate Verify: Signature algorithm ( %04x )",
(unsigned int) algorithm));
/*
* Check the certificate's key type matches the signature alg
*/
if (!mbedtls_pk_can_do(&ssl->session_negotiate->peer_cert->pk, sig_alg)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("signature algorithm doesn't match cert key"));
goto error;
}
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 2);
signature_len = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, signature_len);
status = psa_hash_compute(hash_alg,
verify_buffer,
verify_buffer_len,
verify_hash,
sizeof(verify_hash),
&verify_hash_len);
if (status != PSA_SUCCESS) {
MBEDTLS_SSL_DEBUG_RET(1, "hash computation PSA error", status);
goto error;
}
MBEDTLS_SSL_DEBUG_BUF(3, "verify hash", verify_hash, verify_hash_len);
#if defined(MBEDTLS_X509_RSASSA_PSS_SUPPORT)
if (sig_alg == MBEDTLS_PK_RSASSA_PSS) {
rsassa_pss_options.mgf1_hash_id = md_alg;
rsassa_pss_options.expected_salt_len = PSA_HASH_LENGTH(hash_alg);
options = (const void *) &rsassa_pss_options;
}
#endif /* MBEDTLS_X509_RSASSA_PSS_SUPPORT */
if ((ret = mbedtls_pk_verify_ext(sig_alg, options,
&ssl->session_negotiate->peer_cert->pk,
md_alg, verify_hash, verify_hash_len,
p, signature_len)) == 0) {
return 0;
}
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_pk_verify_ext", ret);
error:
/* RFC 8446 section 4.4.3
*
* If the verification fails, the receiver MUST terminate the handshake
* with a "decrypt_error" alert.
*/
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE);
return MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
}
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
int mbedtls_ssl_tls13_process_certificate_verify(mbedtls_ssl_context *ssl)
{
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
unsigned char verify_buffer[SSL_VERIFY_STRUCT_MAX_SIZE];
size_t verify_buffer_len;
unsigned char transcript[MBEDTLS_TLS1_3_MD_MAX_SIZE];
size_t transcript_len;
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate verify"));
MBEDTLS_SSL_PROC_CHK(
mbedtls_ssl_tls13_fetch_handshake_msg(
ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY, &buf, &buf_len));
/* Need to calculate the hash of the transcript first
* before reading the message since otherwise it gets
* included in the transcript
*/
ret = mbedtls_ssl_get_handshake_transcript(
ssl,
(mbedtls_md_type_t) ssl->handshake->ciphersuite_info->mac,
transcript, sizeof(transcript),
&transcript_len);
if (ret != 0) {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_SSL_INTERNAL_ERROR);
return ret;
}
MBEDTLS_SSL_DEBUG_BUF(3, "handshake hash", transcript, transcript_len);
/* Create verify structure */
ssl_tls13_create_verify_structure(transcript,
transcript_len,
verify_buffer,
&verify_buffer_len,
(ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) ?
MBEDTLS_SSL_IS_SERVER :
MBEDTLS_SSL_IS_CLIENT);
/* Process the message contents */
MBEDTLS_SSL_PROC_CHK(ssl_tls13_parse_certificate_verify(
ssl, buf, buf + buf_len,
verify_buffer, verify_buffer_len));
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_CERTIFICATE_VERIFY,
buf, buf_len));
cleanup:
MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate verify"));
MBEDTLS_SSL_DEBUG_RET(1, "mbedtls_ssl_tls13_process_certificate_verify", ret);
return ret;
#else
((void) ssl);
MBEDTLS_SSL_DEBUG_MSG(1, ("should never happen"));
return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
}
/*
*
* STATE HANDLING: Incoming Certificate.
*
*/
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
/*
* Structure of Certificate message:
*
* enum {
* X509(0),
* RawPublicKey(2),
* (255)
* } CertificateType;
*
* struct {
* select (certificate_type) {
* case RawPublicKey:
* * From RFC 7250 ASN.1_subjectPublicKeyInfo *
* opaque ASN1_subjectPublicKeyInfo<1..2^24-1>;
* case X509:
* opaque cert_data<1..2^24-1>;
* };
* Extension extensions<0..2^16-1>;
* } CertificateEntry;
*
* struct {
* opaque certificate_request_context<0..2^8-1>;
* CertificateEntry certificate_list<0..2^24-1>;
* } Certificate;
*
*/
/* Parse certificate chain send by the server. */
MBEDTLS_CHECK_RETURN_CRITICAL
MBEDTLS_STATIC_TESTABLE
int mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t certificate_request_context_len = 0;
size_t certificate_list_len = 0;
const unsigned char *p = buf;
const unsigned char *certificate_list_end;
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, 4);
certificate_request_context_len = p[0];
certificate_list_len = MBEDTLS_GET_UINT24_BE(p, 1);
p += 4;
/* In theory, the certificate list can be up to 2^24 Bytes, but we don't
* support anything beyond 2^16 = 64K.
*/
if ((certificate_request_context_len != 0) ||
(certificate_list_len >= 0x10000)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate message"));
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
/* In case we tried to reuse a session but it failed */
if (ssl->session_negotiate->peer_cert != NULL) {
mbedtls_x509_crt_free(ssl->session_negotiate->peer_cert);
mbedtls_free(ssl->session_negotiate->peer_cert);
}
if (certificate_list_len == 0) {
ssl->session_negotiate->peer_cert = NULL;
ret = 0;
goto exit;
}
if ((ssl->session_negotiate->peer_cert =
mbedtls_calloc(1, sizeof(mbedtls_x509_crt))) == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("alloc( %" MBEDTLS_PRINTF_SIZET " bytes ) failed",
sizeof(mbedtls_x509_crt)));
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_SSL_ALLOC_FAILED);
return MBEDTLS_ERR_SSL_ALLOC_FAILED;
}
mbedtls_x509_crt_init(ssl->session_negotiate->peer_cert);
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, end, certificate_list_len);
certificate_list_end = p + certificate_list_len;
while (p < certificate_list_end) {
size_t cert_data_len, extensions_len;
const unsigned char *extensions_end;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, 3);
cert_data_len = MBEDTLS_GET_UINT24_BE(p, 0);
p += 3;
/* In theory, the CRT can be up to 2^24 Bytes, but we don't support
* anything beyond 2^16 = 64K. Otherwise as in the TLS 1.2 code,
* check that we have a minimum of 128 bytes of data, this is not
* clear why we need that though.
*/
if ((cert_data_len < 128) || (cert_data_len >= 0x10000)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad Certificate message"));
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, cert_data_len);
ret = mbedtls_x509_crt_parse_der(ssl->session_negotiate->peer_cert,
p, cert_data_len);
switch (ret) {
case 0: /*ok*/
break;
case MBEDTLS_ERR_X509_UNKNOWN_SIG_ALG + MBEDTLS_ERR_OID_NOT_FOUND:
/* Ignore certificate with an unknown algorithm: maybe a
prior certificate was already trusted. */
break;
case MBEDTLS_ERR_X509_ALLOC_FAILED:
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR,
MBEDTLS_ERR_X509_ALLOC_FAILED);
MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
return ret;
case MBEDTLS_ERR_X509_UNKNOWN_VERSION:
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT,
MBEDTLS_ERR_X509_UNKNOWN_VERSION);
MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
return ret;
default:
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_BAD_CERT,
ret);
MBEDTLS_SSL_DEBUG_RET(1, " mbedtls_x509_crt_parse_der", ret);
return ret;
}
p += cert_data_len;
/* Certificate extensions length */
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, 2);
extensions_len = MBEDTLS_GET_UINT16_BE(p, 0);
p += 2;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, certificate_list_end, extensions_len);
extensions_end = p + extensions_len;
handshake->received_extensions = MBEDTLS_SSL_EXT_MASK_NONE;
while (p < extensions_end) {
unsigned int extension_type;
size_t extension_data_len;
/*
* struct {
* ExtensionType extension_type; (2 bytes)
* opaque extension_data<0..2^16-1>;
* } Extension;
*/
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, 4);
extension_type = MBEDTLS_GET_UINT16_BE(p, 0);
extension_data_len = MBEDTLS_GET_UINT16_BE(p, 2);
p += 4;
MBEDTLS_SSL_CHK_BUF_READ_PTR(p, extensions_end, extension_data_len);
ret = mbedtls_ssl_tls13_check_received_extension(
ssl, MBEDTLS_SSL_HS_CERTIFICATE, extension_type,
MBEDTLS_SSL_TLS1_3_ALLOWED_EXTS_OF_CT);
if (ret != 0) {
return ret;
}
switch (extension_type) {
default:
MBEDTLS_SSL_PRINT_EXT(
3, MBEDTLS_SSL_HS_CERTIFICATE,
extension_type, "( ignored )");
break;
}
p += extension_data_len;
}
MBEDTLS_SSL_PRINT_EXTS(3, MBEDTLS_SSL_HS_CERTIFICATE,
handshake->received_extensions);
}
exit:
/* Check that all the message is consumed. */
if (p != end) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad Certificate message"));
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_DECODE_ERROR);
return MBEDTLS_ERR_SSL_DECODE_ERROR;
}
MBEDTLS_SSL_DEBUG_CRT(3, "peer certificate",
ssl->session_negotiate->peer_cert);
return ret;
}
#else
MBEDTLS_CHECK_RETURN_CRITICAL
MBEDTLS_STATIC_TESTABLE
int mbedtls_ssl_tls13_parse_certificate(mbedtls_ssl_context *ssl,
const unsigned char *buf,
const unsigned char *end)
{
((void) ssl);
((void) buf);
((void) end);
return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
}
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
/* Validate certificate chain sent by the server. */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_validate_certificate(mbedtls_ssl_context *ssl)
{
int ret = 0;
int authmode = MBEDTLS_SSL_VERIFY_REQUIRED;
mbedtls_x509_crt *ca_chain;
mbedtls_x509_crl *ca_crl;
const char *ext_oid;
size_t ext_len;
uint32_t verify_result = 0;
/* If SNI was used, overwrite authentication mode
* from the configuration. */
#if defined(MBEDTLS_SSL_SRV_C)
if (ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER) {
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->sni_authmode != MBEDTLS_SSL_VERIFY_UNSET) {
authmode = ssl->handshake->sni_authmode;
} else
#endif
authmode = ssl->conf->authmode;
}
#endif
/*
* If the peer hasn't sent a certificate ( i.e. it sent
* an empty certificate chain ), this is reflected in the peer CRT
* structure being unset.
* Check for that and handle it depending on the
* authentication mode.
*/
if (ssl->session_negotiate->peer_cert == NULL) {
MBEDTLS_SSL_DEBUG_MSG(1, ("peer has no certificate"));
#if defined(MBEDTLS_SSL_SRV_C)
if (ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER) {
/* The client was asked for a certificate but didn't send
* one. The client should know what's going on, so we
* don't send an alert.
*/
ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
if (authmode == MBEDTLS_SSL_VERIFY_OPTIONAL) {
return 0;
} else {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_NO_CERT,
MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE);
return MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE;
}
}
#endif /* MBEDTLS_SSL_SRV_C */
#if defined(MBEDTLS_SSL_CLI_C)
if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_NO_CERT,
MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE);
return MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE;
}
#endif /* MBEDTLS_SSL_CLI_C */
}
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if (ssl->handshake->sni_ca_chain != NULL) {
ca_chain = ssl->handshake->sni_ca_chain;
ca_crl = ssl->handshake->sni_ca_crl;
} else
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
{
ca_chain = ssl->conf->ca_chain;
ca_crl = ssl->conf->ca_crl;
}
/*
* Main check: verify certificate
*/
ret = mbedtls_x509_crt_verify_with_profile(
ssl->session_negotiate->peer_cert,
ca_chain, ca_crl,
ssl->conf->cert_profile,
ssl->hostname,
&verify_result,
ssl->conf->f_vrfy, ssl->conf->p_vrfy);
if (ret != 0) {
MBEDTLS_SSL_DEBUG_RET(1, "x509_verify_cert", ret);
}
/*
* Secondary checks: always done, but change 'ret' only if it was 0
*/
if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
ext_oid = MBEDTLS_OID_SERVER_AUTH;
ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH);
} else {
ext_oid = MBEDTLS_OID_CLIENT_AUTH;
ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_CLIENT_AUTH);
}
if ((mbedtls_x509_crt_check_key_usage(
ssl->session_negotiate->peer_cert,
MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0) ||
(mbedtls_x509_crt_check_extended_key_usage(
ssl->session_negotiate->peer_cert,
ext_oid, ext_len) != 0)) {
MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
if (ret == 0) {
ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
}
}
/* mbedtls_x509_crt_verify_with_profile is supposed to report a
* verification failure through MBEDTLS_ERR_X509_CERT_VERIFY_FAILED,
* with details encoded in the verification flags. All other kinds
* of error codes, including those from the user provided f_vrfy
* functions, are treated as fatal and lead to a failure of
* mbedtls_ssl_tls13_parse_certificate even if verification was optional.
*/
if (authmode == MBEDTLS_SSL_VERIFY_OPTIONAL &&
(ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
ret == MBEDTLS_ERR_SSL_BAD_CERTIFICATE)) {
ret = 0;
}
if (ca_chain == NULL && authmode == MBEDTLS_SSL_VERIFY_REQUIRED) {
MBEDTLS_SSL_DEBUG_MSG(1, ("got no CA chain"));
ret = MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED;
}
if (ret != 0) {
/* The certificate may have been rejected for several reasons.
Pick one and send the corresponding alert. Which alert to send
may be a subject of debate in some cases. */
if (verify_result & MBEDTLS_X509_BADCERT_OTHER) {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED, ret);
} else if (verify_result & MBEDTLS_X509_BADCERT_CN_MISMATCH) {
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_BAD_CERT, ret);
} else if (verify_result & (MBEDTLS_X509_BADCERT_KEY_USAGE |
MBEDTLS_X509_BADCERT_EXT_KEY_USAGE |
MBEDTLS_X509_BADCERT_NS_CERT_TYPE |
MBEDTLS_X509_BADCERT_BAD_PK |
MBEDTLS_X509_BADCERT_BAD_KEY)) {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT, ret);
} else if (verify_result & MBEDTLS_X509_BADCERT_EXPIRED) {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED, ret);
} else if (verify_result & MBEDTLS_X509_BADCERT_REVOKED) {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED, ret);
} else if (verify_result & MBEDTLS_X509_BADCERT_NOT_TRUSTED) {
MBEDTLS_SSL_PEND_FATAL_ALERT(MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA, ret);
} else {
MBEDTLS_SSL_PEND_FATAL_ALERT(
MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN, ret);
}
}
#if defined(MBEDTLS_DEBUG_C)
if (verify_result != 0) {
MBEDTLS_SSL_DEBUG_MSG(3, ("! Certificate verification flags %08x",
(unsigned int) verify_result));
} else {
MBEDTLS_SSL_DEBUG_MSG(3, ("Certificate verification flags clear"));
}
#endif /* MBEDTLS_DEBUG_C */
ssl->session_negotiate->verify_result = verify_result;
return ret;
}
#else /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_validate_certificate(mbedtls_ssl_context *ssl)
{
((void) ssl);
return MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
}
#endif /* MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
int mbedtls_ssl_tls13_process_certificate(mbedtls_ssl_context *ssl)
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> parse certificate"));
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
unsigned char *buf;
size_t buf_len;
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_fetch_handshake_msg(
ssl, MBEDTLS_SSL_HS_CERTIFICATE,
&buf, &buf_len));
/* Parse the certificate chain sent by the peer. */
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_tls13_parse_certificate(ssl, buf,
buf + buf_len));
/* Validate the certificate chain and set the verification results. */
MBEDTLS_SSL_PROC_CHK(ssl_tls13_validate_certificate(ssl));
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_CERTIFICATE, buf, buf_len));
cleanup:
#else /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
(void) ssl;
#endif /* MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED */
MBEDTLS_SSL_DEBUG_MSG(2, ("<= parse certificate"));
return ret;
}
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED)
/*
* enum {
* X509(0),
* RawPublicKey(2),
* (255)
* } CertificateType;
*
* struct {
* select (certificate_type) {
* case RawPublicKey:
* // From RFC 7250 ASN.1_subjectPublicKeyInfo
* opaque ASN1_subjectPublicKeyInfo<1..2^24-1>;
*
* case X509:
* opaque cert_data<1..2^24-1>;
* };
* Extension extensions<0..2^16-1>;
* } CertificateEntry;
*
* struct {
* opaque certificate_request_context<0..2^8-1>;
* CertificateEntry certificate_list<0..2^24-1>;
* } Certificate;
*/
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_write_certificate_body(mbedtls_ssl_context *ssl,
unsigned char *buf,
unsigned char *end,
size_t *out_len)
{
const mbedtls_x509_crt *crt = mbedtls_ssl_own_cert(ssl);
unsigned char *p = buf;
unsigned char *certificate_request_context =
ssl->handshake->certificate_request_context;
unsigned char certificate_request_context_len =
ssl->handshake->certificate_request_context_len;
unsigned char *p_certificate_list_len;
/* ...
* opaque certificate_request_context<0..2^8-1>;
* ...
*/
MBEDTLS_SSL_CHK_BUF_PTR(p, end, certificate_request_context_len + 1);
*p++ = certificate_request_context_len;
if (certificate_request_context_len > 0) {
memcpy(p, certificate_request_context, certificate_request_context_len);
p += certificate_request_context_len;
}
/* ...
* CertificateEntry certificate_list<0..2^24-1>;
* ...
*/
MBEDTLS_SSL_CHK_BUF_PTR(p, end, 3);
p_certificate_list_len = p;
p += 3;
MBEDTLS_SSL_DEBUG_CRT(3, "own certificate", crt);
while (crt != NULL) {
size_t cert_data_len = crt->raw.len;
MBEDTLS_SSL_CHK_BUF_PTR(p, end, cert_data_len + 3 + 2);
MBEDTLS_PUT_UINT24_BE(cert_data_len, p, 0);
p += 3;
memcpy(p, crt->raw.p, cert_data_len);
p += cert_data_len;
crt = crt->next;
/* Currently, we don't have any certificate extensions defined.
* Hence, we are sending an empty extension with length zero.
*/
MBEDTLS_PUT_UINT16_BE(0, p, 0);
p += 2;
}
MBEDTLS_PUT_UINT24_BE(p - p_certificate_list_len - 3,
p_certificate_list_len, 0);
*out_len = p - buf;
MBEDTLS_SSL_PRINT_EXTS(
3, MBEDTLS_SSL_HS_CERTIFICATE, ssl->handshake->sent_extensions);
return 0;
}
int mbedtls_ssl_tls13_write_certificate(mbedtls_ssl_context *ssl)
{
int ret;
unsigned char *buf;
size_t buf_len, msg_len;
MBEDTLS_SSL_DEBUG_MSG(2, ("=> write certificate"));
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_start_handshake_msg(
ssl, MBEDTLS_SSL_HS_CERTIFICATE, &buf, &buf_len));
MBEDTLS_SSL_PROC_CHK(ssl_tls13_write_certificate_body(ssl,
buf,
buf + buf_len,
&msg_len));
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_CERTIFICATE, buf, msg_len));
MBEDTLS_SSL_PROC_CHK(mbedtls_ssl_finish_handshake_msg(
ssl, buf_len, msg_len));
cleanup:
MBEDTLS_SSL_DEBUG_MSG(2, ("<= write certificate"));
return ret;
}
/*
* STATE HANDLING: Output Certificate Verify
*/
int mbedtls_ssl_tls13_check_sig_alg_cert_key_match(uint16_t sig_alg,
mbedtls_pk_context *key)
{
mbedtls_pk_type_t pk_type = (mbedtls_pk_type_t) mbedtls_ssl_sig_from_pk(key);
size_t key_size = mbedtls_pk_get_bitlen(key);
switch (pk_type) {
case MBEDTLS_SSL_SIG_ECDSA:
switch (key_size) {
case 256:
return
sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP256R1_SHA256;
case 384:
return
sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP384R1_SHA384;
case 521:
return
sig_alg == MBEDTLS_TLS1_3_SIG_ECDSA_SECP521R1_SHA512;
default:
break;
}
break;
case MBEDTLS_SSL_SIG_RSA:
switch (sig_alg) {
case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA256: /* Intentional fallthrough */
case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA384: /* Intentional fallthrough */
case MBEDTLS_TLS1_3_SIG_RSA_PSS_RSAE_SHA512:
return 1;
default:
break;
}
break;
default:
break;
}
return 0;
}
MBEDTLS_CHECK_RETURN_CRITICAL
static int ssl_tls13_write_certificate_verify_body(mbedtls_ssl_context *ssl,