Add TLS1.3 process certificate request
Signed-off-by: Xiaofei Bai <xiaofei.bai@arm.com>
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index a87af94..90c20bd 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -136,6 +136,379 @@
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
+
+/*
+ * mbedtls_ssl_tls13_write_sig_alg_ext( )
+ *
+ * enum {
+ * ....
+ * ecdsa_secp256r1_sha256( 0x0403 ),
+ * ecdsa_secp384r1_sha384( 0x0503 ),
+ * ecdsa_secp521r1_sha512( 0x0603 ),
+ * ....
+ * } SignatureScheme;
+ *
+ * struct {
+ * SignatureScheme supported_signature_algorithms<2..2^16-2>;
+ * } SignatureSchemeList;
+ *
+ * Only if we handle at least one key exchange that needs signatures.
+ */
+int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
+ unsigned char *buf,
+ unsigned char *end,
+ size_t *out_len )
+{
+ unsigned char *p = buf;
+ unsigned char *supported_sig_alg; /* Start of supported_signature_algorithms */
+ size_t supported_sig_alg_len = 0; /* Length of supported_signature_algorithms */
+
+ *out_len = 0;
+
+ /* Skip the extension on the client if all allowed key exchanges
+ * are PSK-based. */
+#if defined(MBEDTLS_SSL_CLI_C)
+ if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT &&
+ !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
+ {
+ return( 0 );
+ }
+#endif /* MBEDTLS_SSL_CLI_C */
+
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "adding signature_algorithms extension" ) );
+
+ /* Check if we have space for header and length field:
+ * - extension_type (2 bytes)
+ * - extension_data_length (2 bytes)
+ * - supported_signature_algorithms_length (2 bytes)
+ */
+ MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
+ p += 6;
+
+ /*
+ * Write supported_signature_algorithms
+ */
+ supported_sig_alg = p;
+ for( const uint16_t *sig_alg = ssl->conf->tls13_sig_algs;
+ *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
+ {
+ MBEDTLS_SSL_CHK_BUF_PTR( p, end, 2 );
+ MBEDTLS_PUT_UINT16_BE( *sig_alg, p, 0 );
+ p += 2;
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "signature scheme [%x]", *sig_alg ) );
+ }
+
+ /* Length of supported_signature_algorithms */
+ supported_sig_alg_len = p - supported_sig_alg;
+ if( supported_sig_alg_len == 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "No signature algorithms defined." ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ /* Write extension_type */
+ MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_SIG_ALG, buf, 0 );
+ /* Write extension_data_length */
+ MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len + 2, buf, 2 );
+ /* Write length of supported_signature_algorithms */
+ MBEDTLS_PUT_UINT16_BE( supported_sig_alg_len, buf, 4 );
+
+ /* Output the total length of signature algorithms extension. */
+ *out_len = p - buf;
+
+ ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_SIG_ALG;
+ return( 0 );
+}
+
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+static int ssl_tls13_parse_signature_algorithms_ext( mbedtls_ssl_context *ssl,
+ const unsigned char *buf,
+ const unsigned char *end )
+{
+ size_t sig_alg_list_size; /* size of receive signature algorithms list */
+ const unsigned char *p; /* pointer to individual signature algorithm */
+ const uint16_t *sig_alg; /* iterate through configured signature schemes */
+ unsigned int signature_scheme; /* store received signature algorithm scheme */
+ uint32_t common_idx = 0; /* iterate through received_signature_schemes_list */
+ size_t buf_len = end - buf;
+
+ MBEDTLS_SSL_CHK_BUF_READ_PTR( buf, end, 2 );
+
+ sig_alg_list_size = MBEDTLS_GET_UINT16_BE( buf, 0 );
+ if( sig_alg_list_size + 2 != buf_len ||
+ sig_alg_list_size % 2 != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad signature_algorithms extension" ) );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+ memset( ssl->handshake->recv_sig_schemes_list, 0,
+ sizeof( ssl->handshake->recv_sig_schemes_list ) );
+
+ for( p = buf + 2; p < end && common_idx + 1 < MBEDTLS_PK_SIGNATURE_MAX_SIZE; p += 2 )
+ {
+ signature_scheme = MBEDTLS_GET_UINT16_BE( p, 0 );
+
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "received signature algorithm: 0x%x",
+ signature_scheme ) );
+
+ for( sig_alg = ssl->conf->tls13_sig_algs;
+ *sig_alg != MBEDTLS_TLS1_3_SIG_NONE; sig_alg++ )
+ {
+ if( *sig_alg == signature_scheme )
+ {
+ ssl->handshake->recv_sig_schemes_list[common_idx] = signature_scheme;
+ common_idx++;
+ break;
+ }
+ }
+ }
+
+ if( common_idx == 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "no signature algorithm in common" ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE,
+ MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+ return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+ }
+
+ ssl->handshake->recv_sig_schemes_list[common_idx] = MBEDTLS_TLS1_3_SIG_NONE;
+
+ return( 0 );
+}
+#endif
+
+/*
+ *
+ * STATE HANDLING: CertificateRequest
+ *
+ */
+
+/*
+ * Overview
+ */
+
+/* Coordination:
+ * Deals with the ambiguity of not knowing if a CertificateRequest
+ * will be sent. Returns a negative code on failure, or
+ * - SSL_CERTIFICATE_REQUEST_EXPECT_REQUEST
+ * - SSL_CERTIFICATE_REQUEST_SKIP
+ * indicating if a Certificate Request is expected or not.
+ */
+#define SSL_CERTIFICATE_REQUEST_EXPECT_REQUEST 0
+#define SSL_CERTIFICATE_REQUEST_SKIP 1
+
+/*
+ * Implementation
+ */
+
+static int ssl_tls13_certificate_request_coordinate( mbedtls_ssl_context *ssl )
+{
+ int ret;
+
+ if( mbedtls_ssl_tls13_psk_enabled( ssl ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "<= skip parse certificate request" ) );
+ return( SSL_CERTIFICATE_REQUEST_SKIP );
+ }
+
+ if( ( ret = mbedtls_ssl_read_record( ssl, 0 ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
+ return( ret );
+ }
+ ssl->keep_current_message = 1;
+
+ if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE,
+ MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
+ return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
+ }
+
+ return( SSL_CERTIFICATE_REQUEST_SKIP );
+}
+
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+static int ssl_tls13_parse_certificate_request( mbedtls_ssl_context *ssl,
+ const unsigned char *buf,
+ const unsigned char *end )
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+ const unsigned char *p = buf;
+ const unsigned char *ext = NULL;
+ size_t ext_len = 0;
+ size_t context_len = 0;
+
+
+ /*
+ * struct {
+ * opaque certificate_request_context<0..2^8-1>;
+ * Extension extensions<2..2^16-1>;
+ * } CertificateRequest;
+ */
+
+ /*
+ * Parse certificate_request_context
+ */
+
+ MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 1 );
+ context_len = (size_t) p[0];
+ /* skip context_len */
+ p++;
+
+ /* Fixed length fields are:
+ * - 1 for length of context
+ * - 2 for length of extensions
+ * -----
+ * 3 bytes
+ */
+ MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 3 );
+
+ /* store context ( if necessary ) */
+ if( context_len > 0 )
+ {
+ MBEDTLS_SSL_DEBUG_BUF( 3, "Certificate Request Context",
+ p, context_len );
+
+ ssl->handshake->cert_req_ctx = mbedtls_calloc( context_len, 1 );
+ if( ssl->handshake->cert_req_ctx == NULL )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
+ return ( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+ }
+ memcpy( ssl->handshake->cert_req_ctx, p, context_len );
+
+ /* jump over certificate_request_context */
+ p += context_len;
+ }
+
+ /*
+ * Parse extensions
+ */
+ ext_len = MBEDTLS_GET_UINT16_BE( p, 0 );
+
+ /* At least one extension needs to be present,
+ * namely signature_algorithms ext. */
+ if( ext_len < 4 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
+ MBEDTLS_ERR_SSL_DECODE_ERROR );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+
+ /* skip total extension length */
+ p += 2;
+
+ ext = p; /* jump to extensions */
+ while( ext_len )
+ {
+ size_t ext_id = MBEDTLS_GET_UINT16_BE( ext, 0 );
+ size_t ext_size = MBEDTLS_GET_UINT16_BE( ext, 1 );
+
+ if( ext_size + 4 > ext_len )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
+ MBEDTLS_ERR_SSL_DECODE_ERROR );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+
+ switch( ext_id )
+ {
+ case MBEDTLS_TLS_EXT_SIG_ALG:
+ MBEDTLS_SSL_DEBUG_MSG( 3,
+ ( "found signature_algorithms extension" ) );
+
+ if( ( ret = ssl_tls13_parse_signature_algorithms_ext( ssl,
+ ext + 4, ext + 4 + ext_size ) ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1,
+ "ssl_tls13_parse_signature_algorithms_ext", ret );
+ MBEDTLS_SSL_PEND_FATAL_ALERT(
+ MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR, ret );
+ return( ret );
+ }
+ break;
+
+ default:
+ MBEDTLS_SSL_DEBUG_MSG( 3,
+ ( "unknown extension found: %" MBEDTLS_PRINTF_SIZET " ( ignoring )",
+ ext_id ) );
+ break;
+ }
+
+ ext_len -= 4 + ext_size;
+ ext += 4 + ext_size;
+
+ if( ( ext_len > 0 ) && ( ext_len < 4 ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
+ MBEDTLS_ERR_SSL_DECODE_ERROR );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+ }
+
+ ssl->client_auth = 1;
+ return( 0 );
+}
+#endif /* ( MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED ) */
+
+/* Main entry point; orchestrates the other functions */
+int mbedtls_ssl_tls13_process_certificate_request( mbedtls_ssl_context *ssl )
+{
+ int ret = 0;
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate request" ) );
+
+ /* Coordination step
+ * - Fetch record
+ * - Make sure it's either a CertificateRequest or a ServerHelloDone
+ */
+ MBEDTLS_SSL_PROC_CHK_NEG( ssl_tls13_certificate_request_coordinate( ssl ) );
+
+#if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)
+ if( ret == SSL_CERTIFICATE_REQUEST_EXPECT_REQUEST )
+ {
+ unsigned char *buf;
+ size_t buf_len;
+
+ MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_fetch_handshake_msg( ssl,
+ MBEDTLS_SSL_HS_CERTIFICATE_REQUEST,
+ &buf, &buf_len ) );
+
+ MBEDTLS_SSL_PROC_CHK( ssl_tls13_parse_certificate_request( ssl,
+ buf, buf + buf_len ) );
+
+ mbedtls_ssl_tls13_add_hs_msg_to_checksum(
+ ssl, MBEDTLS_SSL_HS_CERTIFICATE_REQUEST, buf, buf_len );
+ }
+ else
+#endif /* MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED */
+ if( ret == SSL_CERTIFICATE_REQUEST_SKIP )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= skip parse certificate request" ) );
+ }
+ else
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+ return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+ }
+
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "got %s certificate request",
+ ssl->client_auth ? "a" : "no" ) );
+
+cleanup:
+
+ /* In the MPS one would close the read-port here to
+ * ensure there's no overlap of reading and writing. */
+
+ MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate request" ) );
+ return( ret );
+}
+
/*
* STATE HANDLING: Read CertificateVerify
*/
@@ -487,20 +860,20 @@
const unsigned char *end )
{
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- size_t certificate_request_context_len = 0;
+ size_t cert_req_ctx_len = 0;
size_t certificate_list_len = 0;
const unsigned char *p = buf;
const unsigned char *certificate_list_end;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 4 );
- certificate_request_context_len = p[0];
+ cert_req_ctx_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 ) ||
+ if( ( cert_req_ctx_len != 0 ) ||
( certificate_list_len >= 0x10000 ) )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate message" ) );