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TLS1.3: Add server finish processing in client side

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Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
This commit is contained in:
XiaokangQian 2021-09-18 06:20:25 +00:00
parent 91fe315c69
commit aa5f5c1f5d
5 changed files with 522 additions and 1 deletions
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12
include/mbedtls/ssl.h
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@ -39,7 +39,6 @@
#if defined(MBEDTLS_DHM_C)
#include "mbedtls/dhm.h"
#endif
/* Adding guard for MBEDTLS_ECDSA_C to ensure no compile errors due
* to guards also being in ssl_srv.c and ssl_cli.c. There is a gap
* in functionality that access to ecdh_ctx structure is needed for
@ -637,6 +636,7 @@ typedef enum
MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET,
MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT,
#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
MBEDTLS_SSL_END_OF_EARLY_DATA,
MBEDTLS_SSL_ENCRYPTED_EXTENSIONS,
MBEDTLS_SSL_CLIENT_CERTIFICATE_VERIFY,
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
@ -1050,6 +1050,14 @@ typedef void mbedtls_ssl_async_cancel_t( mbedtls_ssl_context *ssl );
#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED &&
!MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */
typedef struct
{
unsigned char client_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
unsigned char server_application_traffic_secret_N[ MBEDTLS_MD_MAX_SIZE ];
unsigned char exporter_master_secret [ MBEDTLS_MD_MAX_SIZE ];
unsigned char resumption_master_secret [ MBEDTLS_MD_MAX_SIZE ];
} mbedtls_ssl_tls1_3_application_secrets;
#if defined(MBEDTLS_SSL_DTLS_SRTP)
#define MBEDTLS_TLS_SRTP_MAX_MKI_LENGTH 255
@ -1114,6 +1122,8 @@ struct mbedtls_ssl_session
* to be studied whether one of them can be removed. */
unsigned char MBEDTLS_PRIVATE(minor_ver); /*!< The TLS version used in the session. */
mbedtls_ssl_tls1_3_application_secrets MBEDTLS_PRIVATE(app_secrets);
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
mbedtls_x509_crt *MBEDTLS_PRIVATE(peer_cert); /*!< peer X.509 cert chain */

103
library/ssl_misc.h
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@ -719,6 +719,104 @@ struct mbedtls_ssl_handshake_params
* but can be overwritten by the HRR. */
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
/*
* State-local variables used during the processing
* of a specific handshake state.
*/
union
{
/* Outgoing Finished message */
struct
{
uint8_t preparation_done;
/* Buffer holding digest of the handshake up to
* but excluding the outgoing finished message. */
unsigned char digest[MBEDTLS_MD_MAX_SIZE];
size_t digest_len;
} finished_out;
/* Incoming Finished message */
struct
{
/* Buffer holding digest of the handshake up to but
* excluding the peer's incoming finished message. */
unsigned char digest[MBEDTLS_MD_MAX_SIZE];
size_t digest_len;
} finished_in;
#if defined(MBEDTLS_SSL_CLI_C)
/* Client, incoming ServerKeyExchange */
struct
{
uint8_t preparation_done;
} srv_key_exchange;
/* Client, incoming ServerHello */
struct
{
#if defined(MBEDTLS_SSL_RENEGOTIATION)
int renego_info_seen;
#else
int dummy;
#endif
} srv_hello_in;
/* Client, outgoing ClientKeyExchange */
struct
{
uint8_t preparation_done;
} cli_key_exch_out;
/* Client, outgoing Certificate Verify */
struct
{
uint8_t preparation_done;
} crt_vrfy_out;
/* Client, outgoing ClientHello */
struct
{
uint8_t preparation_done;
} cli_hello_out;
#endif /* MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SRV_C)
/* Server, outgoing ClientKeyExchange */
struct
{
uint8_t preparation_done;
} cli_key_exch_in;
/* Server, outgoing ClientKeyExchange */
struct
{
uint8_t preparation_done;
} encrypted_extensions_out;
#endif /* MBEDTLS_SSL_SRV_C */
/* Incoming CertificateVerify */
struct
{
unsigned char verify_buffer[ 64 + 33 + 1 + MBEDTLS_MD_MAX_SIZE ];
size_t verify_buffer_len;
} certificate_verify_in;
/* Outgoing CertificateVerify */
struct
{
unsigned char handshake_hash[ MBEDTLS_MD_MAX_SIZE ];
size_t handshake_hash_len;
} certificate_verify_out;
} state_local;
/* End of state-local variables. */
mbedtls_ssl_ciphersuite_t const *ciphersuite_info;
size_t pmslen; /*!< premaster length */
@ -1162,6 +1260,11 @@ static inline int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl )
int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush );
int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl );
int mbedtls_ssl_read_certificate_process(mbedtls_ssl_context *ssl);
int mbedtls_ssl_write_certificate_process(mbedtls_ssl_context *ssl);
int mbedtls_ssl_tls1_3_finished_in_process( mbedtls_ssl_context *ssl );
int mbedtls_ssl_tls1_3_finished_out_process( mbedtls_ssl_context *ssl );
int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl );
int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl );

153
library/ssl_tls13_generic.c
View File

@ -845,6 +845,159 @@ cleanup:
return( ret );
}
/*
*
* STATE HANDLING: Incoming Finished
* Overview
*/
/* Main entry point: orchestrates the other functions */
int mbedtls_ssl_tls1_3_finished_in_process( mbedtls_ssl_context* ssl );
static int ssl_finished_in_preprocess( mbedtls_ssl_context* ssl );
static int ssl_finished_in_postprocess( mbedtls_ssl_context* ssl );
static int ssl_finished_in_parse( mbedtls_ssl_context* ssl,
const unsigned char* buf,
size_t buflen );
/*
* Implementation
*/
int mbedtls_ssl_tls1_3_finished_in_process( mbedtls_ssl_context* ssl )
{
int ret = 0;
unsigned char *buf;
size_t buflen;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse finished" ) );
/* Preprocessing step: Compute handshake digest */
MBEDTLS_SSL_PROC_CHK( ssl_finished_in_preprocess( ssl ) );
MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls1_3_fetch_handshake_msg( ssl,
MBEDTLS_SSL_HS_FINISHED,
&buf, &buflen ) );
MBEDTLS_SSL_PROC_CHK( ssl_finished_in_parse( ssl, buf, buflen ) );
mbedtls_ssl_tls1_3_add_hs_msg_to_checksum(
ssl, MBEDTLS_SSL_HS_FINISHED, buf, buflen );
MBEDTLS_SSL_PROC_CHK( ssl_finished_in_postprocess( ssl ) );
cleanup:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse finished" ) );
return( ret );
}
static int ssl_finished_in_preprocess( mbedtls_ssl_context* ssl )
{
int ret;
ret = mbedtls_ssl_tls1_3_calc_finished( ssl,
ssl->handshake->state_local.finished_in.digest,
sizeof( ssl->handshake->state_local.finished_in.digest ),
&ssl->handshake->state_local.finished_in.digest_len,
ssl->conf->endpoint ^ 1 );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls1_3_calc_finished", ret );
return( ret );
}
return( 0 );
}
static int ssl_finished_in_parse( mbedtls_ssl_context* ssl,
const unsigned char* buf,
size_t buflen )
{
/* Structural validation */
if( buflen != ssl->handshake->state_local.finished_in.digest_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished 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_BUF( 4, "Hash (self-computed):",
ssl->handshake->state_local.finished_in.digest,
ssl->handshake->state_local.finished_in.digest_len );
MBEDTLS_SSL_DEBUG_BUF( 4, "Hash (received message):", buf,
ssl->handshake->state_local.finished_in.digest_len );
/* Semantic validation */
if( mbedtls_ssl_safer_memcmp( buf,
ssl->handshake->state_local.finished_in.digest,
ssl->handshake->state_local.finished_in.digest_len ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );
MBEDTLS_SSL_PEND_FATAL_ALERT( MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR,
MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
}
return( 0 );
}
static int ssl_finished_in_postprocess_cli( mbedtls_ssl_context *ssl )
{
int ret = 0;
mbedtls_ssl_key_set traffic_keys;
mbedtls_ssl_transform *transform_application;
ret = mbedtls_ssl_tls1_3_key_schedule_stage_application( ssl );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1,
"mbedtls_ssl_tls1_3_key_schedule_stage_application", ret );
return( ret );
}
ret = mbedtls_ssl_tls1_3_generate_application_keys(
ssl, &traffic_keys );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1,
"mbedtls_ssl_tls1_3_generate_application_keys", ret );
return( ret );
}
transform_application =
mbedtls_calloc( 1, sizeof( mbedtls_ssl_transform ) );
if( transform_application == NULL )
return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
ret = mbedtls_ssl_tls13_populate_transform(
transform_application,
ssl->conf->endpoint,
ssl->session_negotiate->ciphersuite,
&traffic_keys,
ssl );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls13_populate_transform", ret );
return( ret );
}
ssl->transform_application = transform_application;
mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_END_OF_EARLY_DATA );
return( 0 );
}
static int ssl_finished_in_postprocess( mbedtls_ssl_context* ssl )
{
if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
{
return( ssl_finished_in_postprocess_cli( ssl ) );
}
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
#endif /* MBEDTLS_SSL_TLS_C */

194
library/ssl_tls13_keys.c
View File

@ -564,6 +564,36 @@ int mbedtls_ssl_tls1_3_derive_resumption_master_secret(
return( 0 );
}
int mbedtls_ssl_tls1_3_key_schedule_stage_application(
mbedtls_ssl_context *ssl )
{
int ret = 0;
mbedtls_md_type_t const md_type = ssl->handshake->ciphersuite_info->mac;
#if defined(MBEDTLS_DEBUG_C)
mbedtls_md_info_t const * const md_info = mbedtls_md_info_from_type( md_type );
size_t const md_size = mbedtls_md_get_size( md_info );
#endif /* MBEDTLS_DEBUG_C */
/*
* Compute MasterSecret
*/
ret = mbedtls_ssl_tls1_3_evolve_secret( md_type,
ssl->handshake->tls1_3_master_secrets.handshake,
NULL, 0,
ssl->handshake->tls1_3_master_secrets.app );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls1_3_evolve_secret", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 4, "Master secret",
ssl->handshake->tls1_3_master_secrets.app, md_size );
return( 0 );
}
static int ssl_tls1_3_calc_finished_core( mbedtls_md_type_t md_type,
unsigned char const *base_key,
unsigned char const *transcript,
@ -614,6 +644,54 @@ exit:
return( ret );
}
int mbedtls_ssl_tls1_3_calc_finished( mbedtls_ssl_context* ssl,
unsigned char* dst,
size_t dst_len,
size_t *actual_len,
int from )
{
int ret;
unsigned char transcript[MBEDTLS_MD_MAX_SIZE];
size_t transcript_len;
unsigned char const *base_key = NULL;
mbedtls_md_type_t const md_type = ssl->handshake->ciphersuite_info->mac;
const mbedtls_md_info_t* const md = mbedtls_md_info_from_type( md_type );
size_t const md_size = mbedtls_md_get_size( md );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_tls1_3_calc_finished" ) );
if( dst_len < md_size )
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
ret = mbedtls_ssl_get_handshake_transcript( ssl, md_type,
transcript, sizeof( transcript ),
&transcript_len );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_handshake_transcript", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 4, "handshake hash", transcript, transcript_len );
if( from == MBEDTLS_SSL_IS_CLIENT )
base_key = ssl->handshake->tls1_3_hs_secrets.client_handshake_traffic_secret;
else
base_key = ssl->handshake->tls1_3_hs_secrets.server_handshake_traffic_secret;
ret = ssl_tls1_3_calc_finished_core( md_type, base_key, transcript, dst );
if( ret != 0 )
return( ret );
*actual_len = md_size;
MBEDTLS_SSL_DEBUG_BUF( 3, "verify_data for finished message", dst, md_size );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_tls1_3_calc_finished" ) );
return( 0 );
}
int mbedtls_ssl_tls1_3_create_psk_binder( mbedtls_ssl_context *ssl,
const mbedtls_md_type_t md_type,
unsigned char const *psk, size_t psk_len,
@ -1028,4 +1106,120 @@ int mbedtls_ssl_tls13_key_schedule_stage_handshake( mbedtls_ssl_context *ssl )
return( 0 );
}
/* Generate application traffic keys since any records following a 1-RTT Finished message
* MUST be encrypted under the application traffic key.
*/
int mbedtls_ssl_tls1_3_generate_application_keys(
mbedtls_ssl_context *ssl,
mbedtls_ssl_key_set *traffic_keys )
{
int ret = 0;
/* Address at which to store the application secrets */
mbedtls_ssl_tls1_3_application_secrets * const app_secrets =
&ssl->session_negotiate->app_secrets;
/* Holding the transcript up to and including the ServerFinished */
unsigned char transcript[MBEDTLS_MD_MAX_SIZE];
size_t transcript_len;
/* Variables relating to the hash for the chosen ciphersuite. */
mbedtls_md_type_t md_type;
mbedtls_md_info_t const *md_info;
size_t md_size;
/* Variables relating to the cipher for the chosen ciphersuite. */
mbedtls_cipher_info_t const *cipher_info;
size_t keylen, ivlen;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> derive application traffic keys" ) );
/* Extract basic information about hash and ciphersuite */
cipher_info = mbedtls_cipher_info_from_type(
ssl->handshake->ciphersuite_info->cipher );
keylen = cipher_info->key_bitlen / 8;
ivlen = cipher_info->iv_size;
md_type = ssl->handshake->ciphersuite_info->mac;
md_info = mbedtls_md_info_from_type( md_type );
md_size = mbedtls_md_get_size( md_info );
/* Compute current handshake transcript. It's the caller's responsiblity
* to call this at the right time, that is, after the ServerFinished. */
ret = mbedtls_ssl_get_handshake_transcript( ssl, md_type,
transcript, sizeof( transcript ),
&transcript_len );
if( ret != 0 )
return( ret );
/* Compute application secrets from master secret and transcript hash. */
ret = mbedtls_ssl_tls1_3_derive_application_secrets( md_type,
ssl->handshake->tls1_3_master_secrets.app,
transcript, transcript_len,
app_secrets );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1,
"mbedtls_ssl_tls1_3_derive_application_secrets", ret );
return( ret );
}
/* Derive first epoch of IV + Key for application traffic. */
ret = mbedtls_ssl_tls1_3_make_traffic_keys( md_type,
app_secrets->client_application_traffic_secret_N,
app_secrets->server_application_traffic_secret_N,
md_size, keylen, ivlen, traffic_keys );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_tls1_3_make_traffic_keys", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 4, "Client application traffic secret",
app_secrets->client_application_traffic_secret_N,
md_size );
MBEDTLS_SSL_DEBUG_BUF( 4, "Server application traffic secret",
app_secrets->server_application_traffic_secret_N,
md_size );
/*
* Export client/server application traffic secret 0
*/
#if defined(MBEDTLS_SSL_EXPORT_KEYS)
if( ssl->f_export_keys != NULL )
{
ssl->f_export_keys( ssl->p_export_keys,
MBEDTLS_SSL_KEY_EXPORT_TLS13_CLIENT_APPLICATION_TRAFFIC_SECRET,
app_secrets->client_application_traffic_secret_N, md_size,
ssl->handshake->randbytes + 32,
ssl->handshake->randbytes,
MBEDTLS_SSL_TLS_PRF_NONE /* TODO: FIX! */ );
ssl->f_export_keys( ssl->p_export_keys,
MBEDTLS_SSL_KEY_EXPORT_TLS13_SERVER_APPLICATION_TRAFFIC_SECRET,
app_secrets->server_application_traffic_secret_N, md_size,
ssl->handshake->randbytes + 32,
ssl->handshake->randbytes,
MBEDTLS_SSL_TLS_PRF_NONE /* TODO: FIX! */ );
}
#endif /* MBEDTLS_SSL_EXPORT_KEYS */
MBEDTLS_SSL_DEBUG_BUF( 4, "client application_write_key:",
traffic_keys->client_write_key, keylen );
MBEDTLS_SSL_DEBUG_BUF( 4, "server application write key",
traffic_keys->server_write_key, keylen );
MBEDTLS_SSL_DEBUG_BUF( 4, "client application write IV",
traffic_keys->client_write_iv, ivlen );
MBEDTLS_SSL_DEBUG_BUF( 4, "server application write IV",
traffic_keys->server_write_iv, ivlen );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= derive application traffic keys" ) );
return( 0 );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */

61
library/ssl_tls13_keys.h
View File

@ -570,4 +570,65 @@ int mbedtls_ssl_tls13_key_schedule_stage_handshake( mbedtls_ssl_context *ssl );
int mbedtls_ssl_tls13_generate_handshake_keys( mbedtls_ssl_context *ssl,
mbedtls_ssl_key_set *traffic_keys );
/**
* \brief Transition into application stage of TLS 1.3 key schedule.
*
* The TLS 1.3 key schedule can be viewed as a simple state machine
* with states Initial -> Early -> Handshake -> Application, and
* this function represents the Handshake -> Application transition.
*
* In the handshake stage, mbedtls_ssl_tls1_3_generate_application_keys()
* can be used to derive the handshake traffic keys.
*
* \param ssl The SSL context to operate on. This must be in key schedule
* stage \c Handshake.
*
* \returns \c 0 on success.
* \returns A negative error code on failure.
*/
int mbedtls_ssl_tls1_3_key_schedule_stage_application(
mbedtls_ssl_context *ssl );
/**
* \brief Compute TLS 1.3 application traffic keys.
*
* \param ssl The SSL context to operate on. This must be in
* key schedule stage \c Application, see
* mbedtls_ssl_tls1_3_key_schedule_stage_application().
* \param traffic_keys The address at which to store the application traffic key
* keys. This must be writable but may be uninitialized.
*
* \returns \c 0 on success.
* \returns A negative error code on failure.
*/
int mbedtls_ssl_tls1_3_generate_application_keys(
mbedtls_ssl_context* ssl, mbedtls_ssl_key_set *traffic_keys );
/**
* \brief Calculate content of TLS 1.3 Finished message.
*
* \param ssl The SSL context to operate on. This must be in
* key schedule stage \c Handshake, see
* mbedtls_ssl_tls1_3_key_schedule_stage_application().
* \param dst The address at which to write the Finished content.
* \param dst_len The size of \p dst in bytes.
* \param actual_len The address at which to store the amount of data
* actually written to \p dst upon success.
* \param from The endpoint the Finished message originates from:
* - #MBEDTLS_SSL_IS_CLIENT for the Client's Finished message
* - #MBEDTLS_SSL_IS_SERVER for the Server's Finished message
*
* \note Both client and server call this function twice, once to
* generate their own Finished message, and once to verify the
* peer's Finished message.
* \returns \c 0 on success.
* \returns A negative error code on failure.
*/
int mbedtls_ssl_tls1_3_calc_finished( mbedtls_ssl_context *ssl,
unsigned char *dst,
size_t dst_len,
size_t *actual_len,
int from );
#endif /* MBEDTLS_SSL_TLS1_3_KEYS_H */