Merge pull request #4953 from yuhaoth/pr/add-tls13-read-certificate-verfify
TLS1.3: CertificateVerify:add tls13 read certificate verfify
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index c7d966b..7ca460c 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1639,6 +1639,11 @@
int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl );
/*
+ * Generic handler of Certificate Verify
+ */
+int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl );
+
+/*
* Write TLS 1.3 handshake message tail
*/
int mbedtls_ssl_tls13_finish_handshake_msg( mbedtls_ssl_context *ssl,
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 9c88484..869465c 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1582,7 +1582,12 @@
*/
static int ssl_tls1_3_process_certificate_verify( mbedtls_ssl_context *ssl )
{
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "%s hasn't been implemented", __func__ ) );
+ int ret;
+
+ ret = mbedtls_ssl_tls13_process_certificate_verify( ssl );
+ if( ret != 0 )
+ return( ret );
+
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_SERVER_FINISHED );
return( 0 );
}
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index c8601ce..75b11c9 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -23,14 +23,15 @@
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
+#include <string.h>
+
#include "mbedtls/error.h"
#include "mbedtls/debug.h"
+#include "mbedtls/oid.h"
+#include "mbedtls/platform.h"
#include "ssl_misc.h"
-#include <mbedtls/debug.h>
-#include <mbedtls/oid.h>
-#include <mbedtls/platform.h>
-
+#include "ssl_tls13_keys.h"
int mbedtls_ssl_tls1_3_fetch_handshake_msg( mbedtls_ssl_context *ssl,
unsigned hs_type,
@@ -217,8 +218,300 @@
return( 0 );
}
+/*
+ * 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;
+}
+
+static int ssl_tls13_sig_alg_is_offered( const mbedtls_ssl_context *ssl,
+ uint16_t sig_alg )
+{
+ const uint16_t *tls13_sig_alg = ssl->conf->tls13_sig_algs;
+
+ for( ; *tls13_sig_alg != MBEDTLS_TLS13_SIG_NONE ; tls13_sig_alg++ )
+ {
+ if( *tls13_sig_alg == sig_alg )
+ return( 1 );
+ }
+ return( 0 );
+}
+
+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;
+ const unsigned char *p = buf;
+ uint16_t algorithm;
+ size_t signature_len;
+ mbedtls_pk_type_t sig_alg;
+ mbedtls_md_type_t md_alg;
+ unsigned char verify_hash[MBEDTLS_MD_MAX_SIZE];
+ size_t verify_hash_len;
+
+ /*
+ * 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( ! ssl_tls13_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;
+ }
+
+ /* We currently only support ECDSA-based signatures */
+ switch( algorithm )
+ {
+ case MBEDTLS_TLS13_SIG_ECDSA_SECP256R1_SHA256:
+ md_alg = MBEDTLS_MD_SHA256;
+ sig_alg = MBEDTLS_PK_ECDSA;
+ break;
+ case MBEDTLS_TLS13_SIG_ECDSA_SECP384R1_SHA384:
+ md_alg = MBEDTLS_MD_SHA384;
+ sig_alg = MBEDTLS_PK_ECDSA;
+ break;
+ case MBEDTLS_TLS13_SIG_ECDSA_SECP521R1_SHA512:
+ md_alg = MBEDTLS_MD_SHA512;
+ sig_alg = MBEDTLS_PK_ECDSA;
+ break;
+ default:
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "Certificate Verify: Unknown signature algorithm." ) );
+ 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 );
+
+ /* Hash verify buffer with indicated hash function */
+ switch( md_alg )
+ {
+#if defined(MBEDTLS_SHA256_C)
+ case MBEDTLS_MD_SHA256:
+ verify_hash_len = 32;
+ ret = mbedtls_sha256( verify_buffer, verify_buffer_len, verify_hash, 0 );
+ break;
+#endif /* MBEDTLS_SHA256_C */
+
+#if defined(MBEDTLS_SHA384_C)
+ case MBEDTLS_MD_SHA384:
+ verify_hash_len = 48;
+ ret = mbedtls_sha512( verify_buffer, verify_buffer_len, verify_hash, 1 );
+ break;
+#endif /* MBEDTLS_SHA384_C */
+
+#if defined(MBEDTLS_SHA512_C)
+ case MBEDTLS_MD_SHA512:
+ verify_hash_len = 64;
+ ret = mbedtls_sha512( verify_buffer, verify_buffer_len, verify_hash, 0 );
+ break;
+#endif /* MBEDTLS_SHA512_C */
+
+ default:
+ ret = MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE;
+ break;
+ }
+
+ if( ret != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_RET( 1, "hash computation error", ret );
+ goto error;
+ }
+
+ MBEDTLS_SSL_DEBUG_BUF( 3, "verify hash", verify_hash, verify_hash_len );
+
+ if( ( ret = mbedtls_pk_verify_ext( sig_alg, NULL,
+ &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_KEY_EXCHANGE_WITH_CERT_ENABLED */
+int mbedtls_ssl_tls13_process_certificate_verify( mbedtls_ssl_context *ssl )
+{
+
+#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_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_tls1_3_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,
+ 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_tls1_3_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_KEY_EXCHANGE_WITH_CERT_ENABLED */
+}
+
/*
*
* STATE HANDLING: Incoming Certificate, client-side only currently.
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index 384f433..165b58a 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -22,25 +22,27 @@
/* This requires MBEDTLS_SSL_TLS1_3_LABEL( idx, name, string ) to be defined at
* the point of use. See e.g. the definition of mbedtls_ssl_tls1_3_labels_union
* below. */
-#define MBEDTLS_SSL_TLS1_3_LABEL_LIST \
- MBEDTLS_SSL_TLS1_3_LABEL( finished , "finished" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( resumption , "resumption" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( traffic_upd , "traffic upd" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( exporter , "exporter" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( key , "key" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( iv , "iv" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( c_hs_traffic, "c hs traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( c_ap_traffic, "c ap traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( c_e_traffic , "c e traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( s_hs_traffic, "s hs traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( s_ap_traffic, "s ap traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( s_e_traffic , "s e traffic" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( e_exp_master, "e exp master" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( res_master , "res master" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( exp_master , "exp master" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( ext_binder , "ext binder" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( res_binder , "res binder" ) \
- MBEDTLS_SSL_TLS1_3_LABEL( derived , "derived" )
+#define MBEDTLS_SSL_TLS1_3_LABEL_LIST \
+ MBEDTLS_SSL_TLS1_3_LABEL( finished , "finished" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( resumption , "resumption" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( traffic_upd , "traffic upd" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( exporter , "exporter" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( key , "key" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( iv , "iv" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( c_hs_traffic, "c hs traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( c_ap_traffic, "c ap traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( c_e_traffic , "c e traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( s_hs_traffic, "s hs traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( s_ap_traffic, "s ap traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( s_e_traffic , "s e traffic" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( e_exp_master, "e exp master" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( res_master , "res master" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( exp_master , "exp master" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( ext_binder , "ext binder" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( res_binder , "res binder" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( derived , "derived" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( client_cv , "TLS 1.3, client CertificateVerify" ) \
+ MBEDTLS_SSL_TLS1_3_LABEL( server_cv , "TLS 1.3, server CertificateVerify" )
#define MBEDTLS_SSL_TLS1_3_LABEL( name, string ) \
const unsigned char name [ sizeof(string) - 1 ];
@@ -57,9 +59,12 @@
extern const struct mbedtls_ssl_tls1_3_labels_struct mbedtls_ssl_tls1_3_labels;
+#define MBEDTLS_SSL_TLS1_3_LBL_LEN( LABEL ) \
+ sizeof(mbedtls_ssl_tls1_3_labels.LABEL)
+
#define MBEDTLS_SSL_TLS1_3_LBL_WITH_LEN( LABEL ) \
mbedtls_ssl_tls1_3_labels.LABEL, \
- sizeof(mbedtls_ssl_tls1_3_labels.LABEL)
+ MBEDTLS_SSL_TLS1_3_LBL_LEN( LABEL )
#define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN \
sizeof( union mbedtls_ssl_tls1_3_labels_union )
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 9930210..0e78356 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -8831,8 +8831,11 @@
-c "server hello, chosen ciphersuite: ( 1301 ) - TLS1-3-AES-128-GCM-SHA256" \
-c "ECDH curve: x25519" \
-c "=> ssl_tls1_3_process_server_hello" \
+ -c "<= parse encrypted extensions" \
-c "Certificate verification flags clear" \
- -c "<= parse encrypted extensions"
+ -c "=> parse certificate verify" \
+ -c "<= parse certificate verify" \
+ -c "mbedtls_ssl_tls13_process_certificate_verify() returned 0"
requires_gnutls_tls1_3
requires_gnutls_next_no_ticket
@@ -8861,8 +8864,11 @@
-c "server hello, chosen ciphersuite: ( 1301 ) - TLS1-3-AES-128-GCM-SHA256" \
-c "ECDH curve: x25519" \
-c "=> ssl_tls1_3_process_server_hello" \
+ -c "<= parse encrypted extensions" \
-c "Certificate verification flags clear" \
- -c "<= parse encrypted extensions"
+ -c "=> parse certificate verify" \
+ -c "<= parse certificate verify" \
+ -c "mbedtls_ssl_tls13_process_certificate_verify() returned 0"
# Test heap memory usage after handshake
requires_config_enabled MBEDTLS_MEMORY_DEBUG