diced/src/sample_inputs.rs

// Copyright 2021, The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! This module provides a set of sample input values for a DICE chain, a sample UDS,
//! as well as tuple of CDIs and BCC derived thereof.

use android_hardware_security_dice::aidl::android::hardware::security::dice::{
    Config::Config as BinderConfig, InputValues::InputValues as BinderInputValues, Mode::Mode,
};
use anyhow::{Context, Result};
use dice::ContextImpl;
use diced_open_dice_cbor as dice;
use diced_utils::{cbor, to_dice_input_values};
use std::convert::TryInto;
use std::ffi::CStr;
use std::io::Write;

/// Sample UDS used to perform the root dice flow by `make_sample_bcc_and_cdis`.
pub static UDS: &[u8; dice::CDI_SIZE] = &[
    0x65, 0x4f, 0xab, 0xa9, 0xa5, 0xad, 0x0f, 0x5e, 0x15, 0xc3, 0x12, 0xf7, 0x77, 0x45, 0xfa, 0x55,
    0x18, 0x6a, 0xa6, 0x34, 0xb6, 0x7c, 0x82, 0x7b, 0x89, 0x4c, 0xc5, 0x52, 0xd3, 0x27, 0x35, 0x8e,
];

fn encode_pub_key_ed25519(pub_key: &[u8], stream: &mut dyn Write) -> Result<()> {
    cbor::encode_header(5 /* CBOR MAP */, 5, stream)
        .context("In encode_pub_key_ed25519: Trying to encode map header.")?;
    cbor::encode_number(1, stream)
        .context("In encode_pub_key_ed25519: Trying to encode Key type tag.")?;
    cbor::encode_number(1, stream)
        .context("In encode_pub_key_ed25519: Trying to encode Key type.")?;
    cbor::encode_number(3, stream)
        .context("In encode_pub_key_ed25519: Trying to encode algorithm tag.")?;
    // Encoding a -8 for AlgorithmEdDSA. The encoded number is -1 - <header argument>,
    // the an argument of 7 below.
    cbor::encode_header(1 /* CBOR NEGATIVE INT */, 7 /* -1 -7 = -8*/, stream)
        .context("In encode_pub_key_ed25519: Trying to encode algorithm.")?;
    cbor::encode_number(4, stream)
        .context("In encode_pub_key_ed25519: Trying to encode ops tag.")?;
    // Encoding a single-element array for key ops
    cbor::encode_header(4 /* CBOR ARRAY */, 1, stream)
        .context("In encode_pub_key_ed25519: Trying to encode ops array header.")?;
    // Ops 2 for verify.
    cbor::encode_number(2, stream).context("In encode_pub_key_ed25519: Trying to encode ops.")?;
    cbor::encode_header(1 /* CBOR NEGATIVE INT */, 0 /* -1 -0 = -1*/, stream)
        .context("In encode_pub_key_ed25519: Trying to encode curve tag.")?;
    // Curve 6 for Ed25519
    cbor::encode_number(6, stream).context("In encode_pub_key_ed25519: Trying to encode curve.")?;
    cbor::encode_header(1 /* CBOR NEGATIVE INT */, 1 /* -1 -1 = -2*/, stream)
        .context("In encode_pub_key_ed25519: Trying to encode X coordinate tag.")?;
    cbor::encode_bstr(pub_key, stream)
        .context("In encode_pub_key_ed25519: Trying to encode X coordinate.")?;
    Ok(())
}

/// Derives a tuple of (CDI_ATTEST, CDI_SEAL, BCC) derived of the vector of input values returned
/// by `get_input_values_vector`.
pub fn make_sample_bcc_and_cdis() -> Result<dice::OwnedDiceArtifacts> {
    let mut dice_ctx = dice::OpenDiceCborContext::new();
    let private_key_seed = dice::derive_cdi_private_key_seed(UDS)
        .context("In make_sample_bcc_and_cdis: Trying to derive private key seed.")?;

    let (public_key, _) =
        dice_ctx
            .keypair_from_seed(&private_key_seed[..].try_into().context(
                "In make_sample_bcc_and_cids: Failed to convert seed to array reference.",
            )?)
            .context("In make_sample_bcc_and_cids: Failed to generate key pair.")?;

    let input_values_vector = get_input_values_vector();

    let (cdi_values, mut cert) =
        dice::retry_dice_main_flow(UDS, UDS, &to_dice_input_values(&input_values_vector[0]))
            .context("In make_sample_bcc_and_cdis: Trying to run first main flow.")?;

    let mut bcc: Vec<u8> = vec![];

    cbor::encode_header(4 /* CBOR ARRAY */, 2, &mut bcc)
        .context("In make_sample_bcc_and_cdis: Trying to encode array header.")?;
    encode_pub_key_ed25519(&public_key, &mut bcc)
        .context("In make_sample_bcc_and_cdis: Trying encode pub_key.")?;

    bcc.append(&mut cert);

    let dice_artifacts = dice::retry_bcc_main_flow(
        &cdi_values.cdi_attest,
        &cdi_values.cdi_seal,
        &bcc,
        &to_dice_input_values(&input_values_vector[1]),
    )
    .context("In make_sample_bcc_and_cdis: Trying to run first bcc main flow.")?;
    dice::retry_bcc_main_flow(
        &dice_artifacts.cdi_values.cdi_attest,
        &dice_artifacts.cdi_values.cdi_seal,
        &dice_artifacts.bcc,
        &to_dice_input_values(&input_values_vector[2]),
    )
    .context("In make_sample_bcc_and_cdis: Trying to run second bcc main flow.")
}

fn make_input_values(
    code_hash: dice::Hash,
    authority_hash: dice::Hash,
    config_name: &CStr,
    config_version: u64,
    config_resettable: bool,
    mode: Mode,
    hidden: dice::Hidden,
) -> Result<BinderInputValues> {
    Ok(BinderInputValues {
        codeHash: code_hash,
        config: BinderConfig {
            desc: dice::retry_bcc_format_config_descriptor(
                Some(config_name),
                Some(config_version),
                config_resettable,
            )
            .context("In make_input_values: Failed to format config descriptor.")?,
        },
        authorityHash: authority_hash,
        authorityDescriptor: None,
        hidden,
        mode,
    })
}

/// Returns a set of sample input for a dice chain comprising the android boot loader ABL,
/// the verified boot information AVB, and Android S.
pub fn get_input_values_vector() -> Vec<BinderInputValues> {
    const CODE_HASH1: [u8; dice::HASH_SIZE] = [
        0x16, 0x48, 0xf2, 0x55, 0x53, 0x23, 0xdd, 0x15, 0x2e, 0x83, 0x38, 0xc3, 0x64, 0x38, 0x63,
        0x26, 0x0f, 0xcf, 0x5b, 0xd1, 0x3a, 0xd3, 0x40, 0x3e, 0x23, 0xf8, 0x34, 0x4c, 0x6d, 0xa2,
        0xbe, 0x25, 0x1c, 0xb0, 0x29, 0xe8, 0xc3, 0xfb, 0xb8, 0x80, 0xdc, 0xb1, 0xd2, 0xb3, 0x91,
        0x4d, 0xd3, 0xfb, 0x01, 0x0f, 0xe4, 0xe9, 0x46, 0xa2, 0xc0, 0x26, 0x57, 0x5a, 0xba, 0x30,
        0xf7, 0x15, 0x98, 0x14,
    ];
    const AUTHORITY_HASH1: [u8; dice::HASH_SIZE] = [
        0xf9, 0x00, 0x9d, 0xc2, 0x59, 0x09, 0xe0, 0xb6, 0x98, 0xbd, 0xe3, 0x97, 0x4a, 0xcb, 0x3c,
        0xe7, 0x6b, 0x24, 0xc3, 0xe4, 0x98, 0xdd, 0xa9, 0x6a, 0x41, 0x59, 0x15, 0xb1, 0x23, 0xe6,
        0xc8, 0xdf, 0xfb, 0x52, 0xb4, 0x52, 0xc1, 0xb9, 0x61, 0xdd, 0xbc, 0x5b, 0x37, 0x0e, 0x12,
        0x12, 0xb2, 0xfd, 0xc1, 0x09, 0xb0, 0xcf, 0x33, 0x81, 0x4c, 0xc6, 0x29, 0x1b, 0x99, 0xea,
        0xae, 0xfd, 0xaa, 0x0d,
    ];
    const HIDDEN1: [u8; dice::HIDDEN_SIZE] = [
        0xa2, 0x01, 0xd0, 0xc0, 0xaa, 0x75, 0x3c, 0x06, 0x43, 0x98, 0x6c, 0xc3, 0x5a, 0xb5, 0x5f,
        0x1f, 0x0f, 0x92, 0x44, 0x3b, 0x0e, 0xd4, 0x29, 0x75, 0xe3, 0xdb, 0x36, 0xda, 0xc8, 0x07,
        0x97, 0x4d, 0xff, 0xbc, 0x6a, 0xa4, 0x8a, 0xef, 0xc4, 0x7f, 0xf8, 0x61, 0x7d, 0x51, 0x4d,
        0x2f, 0xdf, 0x7e, 0x8c, 0x3d, 0xa3, 0xfc, 0x63, 0xd4, 0xd4, 0x74, 0x8a, 0xc4, 0x14, 0x45,
        0x83, 0x6b, 0x12, 0x7e,
    ];
    const CODE_HASH2: [u8; dice::HASH_SIZE] = [
        0xa4, 0x0c, 0xcb, 0xc1, 0xbf, 0xfa, 0xcc, 0xfd, 0xeb, 0xf4, 0xfc, 0x43, 0x83, 0x7f, 0x46,
        0x8d, 0xd8, 0xd8, 0x14, 0xc1, 0x96, 0x14, 0x1f, 0x6e, 0xb3, 0xa0, 0xd9, 0x56, 0xb3, 0xbf,
        0x2f, 0xfa, 0x88, 0x70, 0x11, 0x07, 0x39, 0xa4, 0xd2, 0xa9, 0x6b, 0x18, 0x28, 0xe8, 0x29,
        0x20, 0x49, 0x0f, 0xbb, 0x8d, 0x08, 0x8c, 0xc6, 0x54, 0xe9, 0x71, 0xd2, 0x7e, 0xa4, 0xfe,
        0x58, 0x7f, 0xd3, 0xc7,
    ];
    const AUTHORITY_HASH2: [u8; dice::HASH_SIZE] = [
        0xb2, 0x69, 0x05, 0x48, 0x56, 0xb5, 0xfa, 0x55, 0x6f, 0xac, 0x56, 0xd9, 0x02, 0x35, 0x2b,
        0xaa, 0x4c, 0xba, 0x28, 0xdd, 0x82, 0x3a, 0x86, 0xf5, 0xd4, 0xc2, 0xf1, 0xf9, 0x35, 0x7d,
        0xe4, 0x43, 0x13, 0xbf, 0xfe, 0xd3, 0x36, 0xd8, 0x1c, 0x12, 0x78, 0x5c, 0x9c, 0x3e, 0xf6,
        0x66, 0xef, 0xab, 0x3d, 0x0f, 0x89, 0xa4, 0x6f, 0xc9, 0x72, 0xee, 0x73, 0x43, 0x02, 0x8a,
        0xef, 0xbc, 0x05, 0x98,
    ];
    const HIDDEN2: [u8; dice::HIDDEN_SIZE] = [
        0x5b, 0x3f, 0xc9, 0x6b, 0xe3, 0x95, 0x59, 0x40, 0x5e, 0x64, 0xe5, 0x64, 0x3f, 0xfd, 0x21,
        0x09, 0x9d, 0xf3, 0xcd, 0xc7, 0xa4, 0x2a, 0xe2, 0x97, 0xdd, 0xe2, 0x4f, 0xb0, 0x7d, 0x7e,
        0xf5, 0x8e, 0xd6, 0x4d, 0x84, 0x25, 0x54, 0x41, 0x3f, 0x8f, 0x78, 0x64, 0x1a, 0x51, 0x27,
        0x9d, 0x55, 0x8a, 0xe9, 0x90, 0x35, 0xab, 0x39, 0x80, 0x4b, 0x94, 0x40, 0x84, 0xa2, 0xfd,
        0x73, 0xeb, 0x35, 0x7a,
    ];
    const AUTHORITY_HASH3: [u8; dice::HASH_SIZE] = [
        0x04, 0x25, 0x5d, 0x60, 0x5f, 0x5c, 0x45, 0x0d, 0xf2, 0x9a, 0x6e, 0x99, 0x30, 0x03, 0xb8,
        0xd6, 0xe1, 0x99, 0x71, 0x1b, 0xf8, 0x44, 0xfa, 0xb5, 0x31, 0x79, 0x1c, 0x37, 0x68, 0x4e,
        0x1d, 0xc0, 0x24, 0x74, 0x68, 0xf8, 0x80, 0x20, 0x3e, 0x44, 0xb1, 0x43, 0xd2, 0x9c, 0xfc,
        0x12, 0x9e, 0x77, 0x0a, 0xde, 0x29, 0x24, 0xff, 0x2e, 0xfa, 0xc7, 0x10, 0xd5, 0x73, 0xd4,
        0xc6, 0xdf, 0x62, 0x9f,
    ];
    vec![
        make_input_values(
            CODE_HASH1,
            AUTHORITY_HASH1,
            CStr::from_bytes_with_nul(b"ABL\0").unwrap(), // config name
            1,                                            // config version
            true,                                         // resettable
            Mode::NORMAL,
            HIDDEN1,
        )
        .unwrap(),
        make_input_values(
            CODE_HASH2,
            AUTHORITY_HASH2,
            CStr::from_bytes_with_nul(b"AVB\0").unwrap(), // config name
            1,                                            // config version
            true,                                         // resettable
            Mode::NORMAL,
            HIDDEN2,
        )
        .unwrap(),
        make_input_values(
            [0; dice::HASH_SIZE], // code hash
            AUTHORITY_HASH3,
            CStr::from_bytes_with_nul(b"Android\0").unwrap(), // config name
            12,                                               // config version
            true,                                             // resettable
            Mode::NORMAL,
            [0; dice::HIDDEN_SIZE], // hidden,
        )
        .unwrap(),
    ]
}

#[cfg(test)]
mod test {
    use super::*;

    // This simple test checks if the invocation succeeds, essentially it tests
    // if the initial bcc is accepted by `DiceContext::bcc_main_flow`.
    #[test]
    fn make_sample_bcc_and_cdis_test() {
        make_sample_bcc_and_cdis().unwrap();
    }
}