Commit 3148157e authored by Hubert Chathi's avatar Hubert Chathi
Browse files

add support for an incorrect KDF that snuck into Riot 1.0

parent d5c0eb9d

include/olm/sas.h

+8 −0
Original line number Diff line number Diff line
@@ -147,6 +147,14 @@ size_t olm_sas_calculate_mac( 
    void * mac, size_t mac_length

);



// for compatibility with an old version of Riot

size_t olm_sas_calculate_mac_long_kdf(

    OlmSAS * sas,

    void * input, size_t input_length,

    const void * info, size_t info_length,

    void * mac, size_t mac_length

);



/** @} */ // end of SAS group



#ifdef __cplusplus

javascript/olm_sas.js

+16 −0
Original line number Diff line number Diff line
@@ -75,3 +75,19 @@ SAS.prototype['calculate_mac'] = restore_stack(function(input, info) { 
    );

    return Pointer_stringify(mac_buffer);

});



SAS.prototype['calculate_mac_long_kdf'] = restore_stack(function(input, info) {

    var input_array = array_from_string(input);

    var input_buffer = stack(input_array);

    var info_array = array_from_string(info);

    var info_buffer = stack(info_array);

    var mac_length = sas_method(Module['_olm_sas_mac_length'])(this.ptr);

    var mac_buffer = stack(mac_length + NULL_BYTE_PADDING_LENGTH);

    sas_method(Module['_olm_sas_calculate_mac_long_kdf'])(

        this.ptr,

        input_buffer, input_array.length,

        info_buffer, info_array.length,

        mac_buffer, mac_length

    );

    return Pointer_stringify(mac_buffer);

});

src/sas.c

+23 −0
Original line number Diff line number Diff line
@@ -139,3 +139,26 @@ size_t olm_sas_calculate_mac( 
    _olm_encode_base64((const uint8_t *)mac, SHA256_OUTPUT_LENGTH, (uint8_t *)mac);

    return 0;

}



// for compatibility with an old version of Riot

size_t olm_sas_calculate_mac_long_kdf(

    OlmSAS * sas,

    void * input, size_t input_length,

    const void * info, size_t info_length,

    void * mac, size_t mac_length

) {

    if (mac_length < olm_sas_mac_length(sas)) {

        sas->last_error = OLM_OUTPUT_BUFFER_TOO_SMALL;

        return (size_t)-1;

    }

    uint8_t key[256];

    _olm_crypto_hkdf_sha256(

        sas->secret, sizeof(sas->secret),

        NULL, 0,

        (const uint8_t *) info, info_length,

        key, 256

    );

    _olm_crypto_hmac_sha256(key, 256, input, input_length, mac);

    _olm_encode_base64((const uint8_t *)mac, SHA256_OUTPUT_LENGTH, (uint8_t *)mac);

    return 0;

}