Improve readability

Improve readability of the code:
1. move common code to `ssl_internal.h` as `static inline`.
2. Add comments.
3. Use local variables for extension size.
4. Change function signature, by adding buffer size and output length.
5. Take server srtp profile out of the loop.

Signed-off-by: Johan Pascal <johan.pascal@belledonne-communications.com>
This commit is contained in:
Ron Eldor 2018-12-06 17:12:49 +02:00 committed by Johan Pascal
parent a978804a1b
commit 089c9fe9fa
5 changed files with 123 additions and 122 deletions

View file

@ -3257,15 +3257,16 @@ mbedtls_ssl_srtp_profile mbedtls_ssl_get_dtls_srtp_protection_profile
*
* \param ssl SSL context tobe used.
* \param key Buffer to hold the generated key material.
* \param key_len [in/out] key buffer size. outputs the actual number
* of bytes written.
* \param key_buffer_len Key buffer size.
* \param olen the actual number of bytes written to key.
*
* \return 0 on success, #MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL if
* the key buffer is too small to hold the generated key.
*/
int mbedtls_ssl_get_dtls_srtp_key_material( const mbedtls_ssl_context *ssl,
unsigned char *key,
size_t *key_len );
size_t key_buffer_len,
size_t *olen );
/**
* \brief Utility function to get information on DTLS-SRTP profile.

View file

@ -1095,6 +1095,54 @@ int mbedtls_ssl_check_sig_hash( const mbedtls_ssl_context *ssl,
mbedtls_md_type_t md );
#endif
#if defined(MBEDTLS_SSL_DTLS_SRTP)
static inline uint16_t mbedtls_ssl_get_srtp_profile_iana_value
( mbedtls_ssl_srtp_profile profile )
{
uint16_t profile_value = 0xffff;
switch( profile )
{
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80:
profile_value = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE;
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32:
profile_value = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80:
profile_value = MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32:
profile_value = MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE;
break;
default: break;
}
return( profile_value );
}
static inline mbedtls_ssl_srtp_profile mbedtls_ssl_get_srtp_profile_value
( uint16_t srtp_iana_value )
{
mbedtls_ssl_srtp_profile profile_value = MBEDTLS_SRTP_UNSET_PROFILE;
switch( srtp_iana_value )
{
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE:
profile_value = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE:
profile_value = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE:
profile_value = MBEDTLS_SRTP_NULL_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE:
profile_value = MBEDTLS_SRTP_NULL_HMAC_SHA1_32;
break;
default: break;
}
return( profile_value );
}
#endif
#if defined(MBEDTLS_X509_CRT_PARSE_C)
static inline mbedtls_pk_context *mbedtls_ssl_own_key( mbedtls_ssl_context *ssl )
{

View file

@ -763,6 +763,8 @@ static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
unsigned char *p = buf;
size_t protection_profiles_index = 0;
size_t mki_len = 0, i;
size_t ext_len = 0;
uint16_t profile_value = 0;
*olen = 0;
@ -795,10 +797,10 @@ static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
* ssl->conf->dtls_srtp_profile_list_len * 2 (each profile is 2 bytes length ),
* 1 byte for srtp_mki vector length and the mki_len value
*/
*p++ = (unsigned char)( ( ( 2 + 2 * ( ssl->conf->dtls_srtp_profile_list_len )
+ 1 + mki_len ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( ( 2 + 2 * (ssl->conf->dtls_srtp_profile_list_len )
+ 1 + mki_len ) ) & 0xFF );
ext_len = 2 + 2 * ( ssl->conf->dtls_srtp_profile_list_len ) + 1 + mki_len;
*p++ = (unsigned char)( ( ( ext_len & 0xFF00 ) >> 8 ) & 0xFF );
*p++ = (unsigned char)( ext_len & 0xFF );
/* protection profile length: 2*(ssl->conf->dtls_srtp_profile_list_len) */
*p++ = (unsigned char)( ( ( 2 * (ssl->conf->dtls_srtp_profile_list_len) )
@ -810,45 +812,23 @@ static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
protection_profiles_index < ssl->conf->dtls_srtp_profile_list_len;
protection_profiles_index++ )
{
switch( ssl->conf->dtls_srtp_profile_list[protection_profiles_index] ) {
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE ) );
*p++ = ( ( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE )
>> 8 ) & 0xFF );
*p++ = ( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE )
& 0xFF );
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE ) );
*p++ = ( ( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE )
>> 8 ) & 0xFF );
*p++ = ( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE )
& 0xFF );
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE ) );
*p++ = ( ( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE ) >> 8 )
& 0xFF ) ;
*p++ = ( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE ) & 0xFF );
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE ) );
*p++ = ( ( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE ) >> 8 )
& 0xFF );
*p++ = ( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE ) & 0xFF );
break;
default:
/*
* Note: we shall never arrive here as protection profiles
* is checked by ssl_set_dtls_srtp_protection_profiles function
*/
MBEDTLS_SSL_DEBUG_MSG( 1, ( "client hello, ignore illegal DTLS-SRTP protection profile %d",
ssl->conf->dtls_srtp_profile_list[protection_profiles_index] ) );
break;
profile_value = mbedtls_ssl_get_srtp_profile_iana_value
( ssl->conf->dtls_srtp_profile_list[protection_profiles_index] );
if( profile_value != 0xFFFF )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "ssl_write_use_srtp_ext, add profile: %04x",
profile_value ) );
*p++ = ( ( profile_value >> 8 ) & 0xFF );
*p++ = ( profile_value & 0xFF );
}
else
{
/*
* Note: we shall never arrive here as protection profiles
* is checked by ssl_set_dtls_srtp_protection_profiles function
*/
MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, ignore illegal DTLS-SRTP protection profile %d",
ssl->conf->dtls_srtp_profile_list[protection_profiles_index] ) );
}
}
@ -1884,13 +1864,17 @@ static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
* protection profile length must be 0x0002 as we must have only
* one protection profile in server Hello
*/
if( ( (uint16_t)( ( buf[0] << 8 ) | buf[1] ) ) != 0x0002 )
if( ( buf[0] != 0 ) || ( buf[1] != 2 ) )
{
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
}
else
server_protection_profile_value = ( buf[2] << 8 ) | buf[3];
server_protection = mbedtls_ssl_get_srtp_profile_value( server_protection_profile_value );
profile_info = mbedtls_ssl_dtls_srtp_profile_info_from_id( server_protection );
if( profile_info != NULL )
{
server_protection_profile_value = ( buf[2] << 8 ) | buf[3];
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s", profile_info->name ) );
}
ssl->dtls_srtp_info.chosen_dtls_srtp_profile = MBEDTLS_SRTP_UNSET_PROFILE;
@ -1900,29 +1884,6 @@ static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
*/
for( i=0; i < ssl->conf->dtls_srtp_profile_list_len; i++)
{
switch( server_protection_profile_value ) {
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE:
server_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE:
server_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE:
server_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE:
server_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_32;
break;
default:
server_protection = MBEDTLS_SRTP_UNSET_PROFILE;
break;
}
profile_info = mbedtls_ssl_dtls_srtp_profile_info_from_id( server_protection );
if( profile_info != NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found srtp profile: %s", profile_info->name ) );
}
if( server_protection == ssl->conf->dtls_srtp_profile_list[i] ) {
ssl->dtls_srtp_info.chosen_dtls_srtp_profile = ssl->conf->dtls_srtp_profile_list[i];
MBEDTLS_SSL_DEBUG_MSG( 3, ( "selected srtp profile: %s", profile_info->name ) );
@ -4168,7 +4129,31 @@ static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
if( ssl->client_auth == 0 || mbedtls_ssl_own_cert( ssl ) == NULL )
{
#if defined(MBEDTLS_SSL_DTLS_SRTP)
/* check if we have a chosen srtp protection profile */
/*
* Check if we have a chosen srtp protection profile.
* According to RFC 5764 section 4.1 client certificate in dtls srtp
* is mandatory:
* Client Server
*
* ClientHello + use_srtp -------->
* ServerHello + use_srtp
* Certificate*
* ServerKeyExchange*
* ertificateRequest*
* <-------- ServerHelloDone
* Certificate*
* ClientKeyExchange
* CertificateVerify*
* [ChangeCipherSpec]
* Finished -------->
* [ChangeCipherSpec]
* <-------- Finished
* SRTP packets <-------> SRTP packets
*
* Note that '*' indicates messages that are not always sent in DTLS.
* The CertificateRequest, client and server Certificates, and
* CertificateVerify will be sent in DTLS-SRTP.
*/
if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile != MBEDTLS_SRTP_UNSET_PROFILE )
{
return ( MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE );

View file

@ -822,25 +822,8 @@ static int ssl_parse_use_srtp_ext( mbedtls_ssl_context *ssl,
{
/* + 2 to skip the length field */
uint16_t protection_profile_value = buf[j + 2] << 8 | buf[j+3];
client_protection = mbedtls_ssl_get_srtp_profile_value( protection_profile_value );
switch ( protection_profile_value )
{
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE:
client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE:
client_protection = MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE:
client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_80;
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE:
client_protection = MBEDTLS_SRTP_NULL_HMAC_SHA1_32;
break;
default:
client_protection = MBEDTLS_SRTP_UNSET_PROFILE;
break;
}
profile_info = mbedtls_ssl_dtls_srtp_profile_info_from_id( client_protection );
if( profile_info != NULL )
{
@ -2624,6 +2607,7 @@ static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
size_t *olen )
{
size_t mki_len = 0, ext_len = 0, i;
uint16_t profile_value = 0;
if( ssl->dtls_srtp_info.chosen_dtls_srtp_profile == MBEDTLS_SRTP_UNSET_PROFILE )
{
@ -2653,34 +2637,16 @@ static void ssl_write_use_srtp_ext( mbedtls_ssl_context *ssl,
/* protection profile length: 2 */
buf[4] = 0x00;
buf[5] = 0x02;
switch (ssl->dtls_srtp_info.chosen_dtls_srtp_profile) {
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80:
buf[6] = (unsigned char)( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE >> 8 )
& 0xFF );
buf[7] = (unsigned char)( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_80_IANA_VALUE )
& 0xFF );
break;
case MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32:
buf[6] = (unsigned char)( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE >> 8 )
& 0xFF );
buf[7] = (unsigned char)( ( MBEDTLS_SRTP_AES128_CM_HMAC_SHA1_32_IANA_VALUE )
& 0xFF );
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_80:
buf[6] = (unsigned char)( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE >> 8 )
& 0xFF );
buf[7] = (unsigned char)( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_80_IANA_VALUE )
& 0xFF );
break;
case MBEDTLS_SRTP_NULL_HMAC_SHA1_32:
buf[6] = (unsigned char)( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE >> 8 )
& 0xFF );
buf[7] = (unsigned char)( ( MBEDTLS_SRTP_NULL_HMAC_SHA1_32_IANA_VALUE )
& 0xFF );
break;
default:
*olen = 0;
return;
profile_value = mbedtls_ssl_get_srtp_profile_iana_value( ssl->dtls_srtp_info.chosen_dtls_srtp_profile );
if( profile_value != 0xFFFF )
{
buf[6] = (unsigned char)( ( profile_value >> 8 ) & 0xFF );
buf[7] = (unsigned char)( profile_value & 0xFF );
}
else
{
*olen = 0;
return;
}
buf[8] = mki_len & 0xFF;

View file

@ -4838,18 +4838,19 @@ mbedtls_ssl_srtp_profile
int mbedtls_ssl_get_dtls_srtp_key_material( const mbedtls_ssl_context *ssl,
unsigned char *key,
size_t *key_len )
size_t key_buffer_len,
size_t *olen )
{
/* check output buffer size */
if( *key_len < ssl->dtls_srtp_info.dtls_srtp_keys_len )
if( key_buffer_len < ssl->dtls_srtp_info.dtls_srtp_keys_len )
{
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
}
memcpy( key, ssl->dtls_srtp_info.dtls_srtp_keys,
ssl->dtls_srtp_info.dtls_srtp_keys_len );
*key_len = ssl->dtls_srtp_info.dtls_srtp_keys_len;
*olen = ssl->dtls_srtp_info.dtls_srtp_keys_len;
return( 0 );
}