Files
chatmail-core/src/pgp.rs
Friedel Ziegelmayer 0c03024b97 feat: update dependencies
* feat: update dependencies

updates

- pgp
- async-std
- surf
- mailparse

* simplify dev deps

* more deps

* fixup

* fixup
2020-09-21 23:53:53 +02:00

598 lines
19 KiB
Rust
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

//! OpenPGP helper module using [rPGP facilities](https://github.com/rpgp/rpgp)
use std::collections::{BTreeMap, HashSet};
use std::io;
use std::io::Cursor;
use pgp::armor::BlockType;
use pgp::composed::{
Deserializable, KeyType as PgpKeyType, Message, SecretKeyParamsBuilder, SignedPublicKey,
SignedPublicSubKey, SignedSecretKey, SubkeyParamsBuilder,
};
use pgp::crypto::{HashAlgorithm, SymmetricKeyAlgorithm};
use pgp::types::{
CompressionAlgorithm, KeyTrait, Mpi, PublicKeyTrait, SecretKeyTrait, StringToKey,
};
use rand::{thread_rng, CryptoRng, Rng};
use crate::constants::KeyGenType;
use crate::dc_tools::EmailAddress;
use crate::error::{bail, ensure, format_err, Result};
use crate::key::{DcKey, Fingerprint};
use crate::keyring::Keyring;
pub const HEADER_AUTOCRYPT: &str = "autocrypt-prefer-encrypt";
pub const HEADER_SETUPCODE: &str = "passphrase-begin";
/// A wrapper for rPGP public key types
#[derive(Debug)]
enum SignedPublicKeyOrSubkey<'a> {
Key(&'a SignedPublicKey),
Subkey(&'a SignedPublicSubKey),
}
impl<'a> KeyTrait for SignedPublicKeyOrSubkey<'a> {
fn fingerprint(&self) -> Vec<u8> {
match self {
Self::Key(k) => k.fingerprint(),
Self::Subkey(k) => k.fingerprint(),
}
}
fn key_id(&self) -> pgp::types::KeyId {
match self {
Self::Key(k) => k.key_id(),
Self::Subkey(k) => k.key_id(),
}
}
fn algorithm(&self) -> pgp::crypto::PublicKeyAlgorithm {
match self {
Self::Key(k) => k.algorithm(),
Self::Subkey(k) => k.algorithm(),
}
}
}
impl<'a> PublicKeyTrait for SignedPublicKeyOrSubkey<'a> {
fn verify_signature(
&self,
hash: HashAlgorithm,
data: &[u8],
sig: &[Mpi],
) -> pgp::errors::Result<()> {
match self {
Self::Key(k) => k.verify_signature(hash, data, sig),
Self::Subkey(k) => k.verify_signature(hash, data, sig),
}
}
fn encrypt<R: Rng + CryptoRng>(
&self,
rng: &mut R,
plain: &[u8],
) -> pgp::errors::Result<Vec<Mpi>> {
match self {
Self::Key(k) => k.encrypt(rng, plain),
Self::Subkey(k) => k.encrypt(rng, plain),
}
}
fn to_writer_old(&self, writer: &mut impl io::Write) -> pgp::errors::Result<()> {
match self {
Self::Key(k) => k.to_writer_old(writer),
Self::Subkey(k) => k.to_writer_old(writer),
}
}
}
/// Split data from PGP Armored Data as defined in https://tools.ietf.org/html/rfc4880#section-6.2.
///
/// Returns (type, headers, base64 encoded body).
pub fn split_armored_data(buf: &[u8]) -> Result<(BlockType, BTreeMap<String, String>, Vec<u8>)> {
use std::io::Read;
let cursor = Cursor::new(buf);
let mut dearmor = pgp::armor::Dearmor::new(cursor);
let mut bytes = Vec::with_capacity(buf.len());
dearmor.read_to_end(&mut bytes)?;
ensure!(dearmor.typ.is_some(), "Failed to parse type");
let typ = dearmor.typ.unwrap();
// normalize headers
let headers = dearmor
.headers
.into_iter()
.map(|(key, value)| (key.trim().to_lowercase(), value.trim().to_string()))
.collect();
Ok((typ, headers, bytes))
}
/// Error with generating a PGP keypair.
///
/// Most of these are likely coding errors rather than user errors
/// since all variability is hardcoded.
#[derive(Debug, thiserror::Error)]
#[error("PgpKeygenError: {message}")]
pub struct PgpKeygenError {
message: String,
#[source]
cause: anyhow::Error,
}
impl PgpKeygenError {
fn new(message: impl Into<String>, cause: impl Into<anyhow::Error>) -> Self {
Self {
message: message.into(),
cause: cause.into(),
}
}
}
/// A PGP keypair.
///
/// This has it's own struct to be able to keep the public and secret
/// keys together as they are one unit.
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct KeyPair {
pub addr: EmailAddress,
pub public: SignedPublicKey,
pub secret: SignedSecretKey,
}
/// Create a new key pair.
pub(crate) fn create_keypair(
addr: EmailAddress,
keygen_type: KeyGenType,
) -> std::result::Result<KeyPair, PgpKeygenError> {
let (secret_key_type, public_key_type) = match keygen_type {
KeyGenType::Rsa2048 => (PgpKeyType::Rsa(2048), PgpKeyType::Rsa(2048)),
KeyGenType::Ed25519 | KeyGenType::Default => (PgpKeyType::EdDSA, PgpKeyType::ECDH),
};
let user_id = format!("<{}>", addr);
let key_params = SecretKeyParamsBuilder::default()
.key_type(secret_key_type)
.can_create_certificates(true)
.can_sign(true)
.primary_user_id(user_id)
.passphrase(None)
.preferred_symmetric_algorithms(smallvec![
SymmetricKeyAlgorithm::AES256,
SymmetricKeyAlgorithm::AES192,
SymmetricKeyAlgorithm::AES128,
])
.preferred_hash_algorithms(smallvec![
HashAlgorithm::SHA2_256,
HashAlgorithm::SHA2_384,
HashAlgorithm::SHA2_512,
HashAlgorithm::SHA2_224,
HashAlgorithm::SHA1,
])
.preferred_compression_algorithms(smallvec![
CompressionAlgorithm::ZLIB,
CompressionAlgorithm::ZIP,
])
.subkey(
SubkeyParamsBuilder::default()
.key_type(public_key_type)
.can_encrypt(true)
.passphrase(None)
.build()
.unwrap(),
)
.build()
.map_err(|err| PgpKeygenError::new("invalid key params", format_err!(err)))?;
let key = key_params
.generate()
.map_err(|err| PgpKeygenError::new("invalid params", err))?;
let private_key = key.sign(|| "".into()).expect("failed to sign secret key");
let public_key = private_key.public_key();
let public_key = public_key
.sign(&private_key, || "".into())
.map_err(|err| PgpKeygenError::new("failed to sign public key", err))?;
private_key
.verify()
.map_err(|err| PgpKeygenError::new("invalid private key generated", err))?;
public_key
.verify()
.map_err(|err| PgpKeygenError::new("invalid public key generated", err))?;
Ok(KeyPair {
addr,
public: public_key,
secret: private_key,
})
}
/// Select public key or subkey to use for encryption.
///
/// First, tries to use subkeys. If none of the subkeys are suitable
/// for encryption, tries to use primary key. Returns `None` if the public
/// key cannot be used for encryption.
///
/// TODO: take key flags and expiration dates into account
fn select_pk_for_encryption(key: &SignedPublicKey) -> Option<SignedPublicKeyOrSubkey> {
key.public_subkeys
.iter()
.find(|subkey| subkey.is_encryption_key())
.map_or_else(
|| {
// No usable subkey found, try primary key
if key.is_encryption_key() {
Some(SignedPublicKeyOrSubkey::Key(key))
} else {
None
}
},
|subkey| Some(SignedPublicKeyOrSubkey::Subkey(subkey)),
)
}
/// Encrypts `plain` text using `public_keys_for_encryption`
/// and signs it using `private_key_for_signing`.
pub async fn pk_encrypt(
plain: &[u8],
public_keys_for_encryption: Keyring<SignedPublicKey>,
private_key_for_signing: Option<SignedSecretKey>,
) -> Result<String> {
let lit_msg = Message::new_literal_bytes("", plain);
async_std::task::spawn_blocking(move || {
let pkeys: Vec<SignedPublicKeyOrSubkey> = public_keys_for_encryption
.keys()
.iter()
.filter_map(|key| select_pk_for_encryption(key))
.collect();
let pkeys_refs: Vec<&SignedPublicKeyOrSubkey> = pkeys.iter().collect();
let mut rng = thread_rng();
// TODO: measure time
let encrypted_msg = if let Some(ref skey) = private_key_for_signing {
lit_msg
.sign(skey, || "".into(), Default::default())
.and_then(|msg| msg.compress(CompressionAlgorithm::ZLIB))
.and_then(|msg| msg.encrypt_to_keys(&mut rng, Default::default(), &pkeys_refs))
} else {
lit_msg.encrypt_to_keys(&mut rng, Default::default(), &pkeys_refs)
};
let msg = encrypted_msg?;
let encoded_msg = msg.to_armored_string(None)?;
Ok(encoded_msg)
})
.await
}
/// Decrypts the message with keys from the private key keyring.
///
/// Receiver private keys are provided in
/// `private_keys_for_decryption`.
///
/// If `ret_signature_fingerprints` is not `None`, stores fingerprints
/// of all keys from the `public_keys_for_validation` keyring that
/// have valid signatures there.
#[allow(clippy::implicit_hasher)]
pub async fn pk_decrypt(
ctext: Vec<u8>,
private_keys_for_decryption: Keyring<SignedSecretKey>,
public_keys_for_validation: Keyring<SignedPublicKey>,
ret_signature_fingerprints: Option<&mut HashSet<Fingerprint>>,
) -> Result<Vec<u8>> {
let msgs = async_std::task::spawn_blocking(move || {
let cursor = Cursor::new(ctext);
let (msg, _) = Message::from_armor_single(cursor)?;
let skeys: Vec<&SignedSecretKey> = private_keys_for_decryption.keys().iter().collect();
let (decryptor, _) = msg.decrypt(|| "".into(), || "".into(), &skeys[..])?;
decryptor.collect::<pgp::errors::Result<Vec<_>>>()
})
.await?;
if let Some(msg) = msgs.into_iter().next() {
// get_content() will decompress the message if needed,
// but this avoids decompressing it again to check signatures
let msg = msg.decompress()?;
let content = match msg.get_content()? {
Some(content) => content,
None => bail!("The decrypted message is empty"),
};
if let Some(ret_signature_fingerprints) = ret_signature_fingerprints {
if !public_keys_for_validation.is_empty() {
let fingerprints = async_std::task::spawn_blocking(move || {
let pkeys = public_keys_for_validation.keys();
let mut fingerprints: Vec<Fingerprint> = Vec::new();
if let signed_msg @ pgp::composed::Message::Signed { .. } = msg {
for pkey in pkeys {
if signed_msg.verify(&pkey.primary_key).is_ok() {
let fp = DcKey::fingerprint(pkey);
fingerprints.push(fp);
}
}
}
fingerprints
})
.await;
ret_signature_fingerprints.extend(fingerprints);
}
}
Ok(content)
} else {
bail!("No valid messages found");
}
}
/// Symmetric encryption.
pub async fn symm_encrypt(passphrase: &str, plain: &[u8]) -> Result<String> {
let lit_msg = Message::new_literal_bytes("", plain);
let passphrase = passphrase.to_string();
async_std::task::spawn_blocking(move || {
let mut rng = thread_rng();
let s2k = StringToKey::new_default(&mut rng);
let msg =
lit_msg.encrypt_with_password(&mut rng, s2k, Default::default(), || passphrase)?;
let encoded_msg = msg.to_armored_string(None)?;
Ok(encoded_msg)
})
.await
}
/// Symmetric decryption.
pub async fn symm_decrypt<T: std::io::Read + std::io::Seek>(
passphrase: &str,
ctext: T,
) -> Result<Vec<u8>> {
let (enc_msg, _) = Message::from_armor_single(ctext)?;
let passphrase = passphrase.to_string();
async_std::task::spawn_blocking(move || {
let decryptor = enc_msg.decrypt_with_password(|| passphrase)?;
let msgs = decryptor.collect::<pgp::errors::Result<Vec<_>>>()?;
if let Some(msg) = msgs.first() {
match msg.get_content()? {
Some(content) => Ok(content),
None => bail!("Decrypted message is empty"),
}
} else {
bail!("No valid messages found")
}
})
.await
}
#[cfg(test)]
mod tests {
use super::*;
use crate::test_utils::*;
use lazy_static::lazy_static;
#[test]
fn test_split_armored_data_1() {
let (typ, _headers, base64) = split_armored_data(
b"-----BEGIN PGP MESSAGE-----\nNoVal:\n\naGVsbG8gd29ybGQ=\n-----END PGP MESSAGE----",
)
.unwrap();
assert_eq!(typ, BlockType::Message);
assert!(!base64.is_empty());
assert_eq!(
std::string::String::from_utf8(base64).unwrap(),
"hello world"
);
}
#[test]
fn test_split_armored_data_2() {
let (typ, headers, base64) = split_armored_data(
b"-----BEGIN PGP PRIVATE KEY BLOCK-----\nAutocrypt-Prefer-Encrypt: mutual \n\naGVsbG8gd29ybGQ=\n-----END PGP PRIVATE KEY BLOCK-----"
)
.unwrap();
assert_eq!(typ, BlockType::PrivateKey);
assert!(!base64.is_empty());
assert_eq!(headers.get(HEADER_AUTOCRYPT), Some(&"mutual".to_string()));
}
#[test]
fn test_create_keypair() {
let keypair0 = create_keypair(
EmailAddress::new("foo@bar.de").unwrap(),
KeyGenType::Default,
)
.unwrap();
let keypair1 = create_keypair(
EmailAddress::new("two@zwo.de").unwrap(),
KeyGenType::Default,
)
.unwrap();
assert_ne!(keypair0.public, keypair1.public);
}
/// [Key] objects to use in tests.
struct TestKeys {
alice_secret: SignedSecretKey,
alice_public: SignedPublicKey,
bob_secret: SignedSecretKey,
bob_public: SignedPublicKey,
}
impl TestKeys {
fn new() -> TestKeys {
let alice = alice_keypair();
let bob = bob_keypair();
TestKeys {
alice_secret: alice.secret.clone(),
alice_public: alice.public,
bob_secret: bob.secret.clone(),
bob_public: bob.public,
}
}
}
/// The original text of [CTEXT_SIGNED]
static CLEARTEXT: &[u8] = b"This is a test";
lazy_static! {
/// Initialised [TestKeys] for tests.
static ref KEYS: TestKeys = TestKeys::new();
/// A cyphertext encrypted to Alice & Bob, signed by Alice.
static ref CTEXT_SIGNED: String = {
let mut keyring = Keyring::new();
keyring.add(KEYS.alice_public.clone());
keyring.add(KEYS.bob_public.clone());
futures_lite::future::block_on(pk_encrypt(CLEARTEXT, keyring, Some(KEYS.alice_secret.clone()))).unwrap()
};
/// A cyphertext encrypted to Alice & Bob, not signed.
static ref CTEXT_UNSIGNED: String = {
let mut keyring = Keyring::new();
keyring.add(KEYS.alice_public.clone());
keyring.add(KEYS.bob_public.clone());
futures_lite::future::block_on(pk_encrypt(CLEARTEXT, keyring, None)).unwrap()
};
}
#[test]
fn test_encrypt_signed() {
assert!(!CTEXT_SIGNED.is_empty());
assert!(CTEXT_SIGNED.starts_with("-----BEGIN PGP MESSAGE-----"));
}
#[test]
fn test_encrypt_unsigned() {
assert!(!CTEXT_UNSIGNED.is_empty());
assert!(CTEXT_UNSIGNED.starts_with("-----BEGIN PGP MESSAGE-----"));
}
#[async_std::test]
async fn test_decrypt_singed() {
// Check decrypting as Alice
let mut decrypt_keyring: Keyring<SignedSecretKey> = Keyring::new();
decrypt_keyring.add(KEYS.alice_secret.clone());
let mut sig_check_keyring: Keyring<SignedPublicKey> = Keyring::new();
sig_check_keyring.add(KEYS.alice_public.clone());
let mut valid_signatures: HashSet<Fingerprint> = Default::default();
let plain = pk_decrypt(
CTEXT_SIGNED.as_bytes().to_vec(),
decrypt_keyring,
sig_check_keyring,
Some(&mut valid_signatures),
)
.await
.map_err(|err| println!("{:?}", err))
.unwrap();
assert_eq!(plain, CLEARTEXT);
assert_eq!(valid_signatures.len(), 1);
// Check decrypting as Bob
let mut decrypt_keyring = Keyring::new();
decrypt_keyring.add(KEYS.bob_secret.clone());
let mut sig_check_keyring = Keyring::new();
sig_check_keyring.add(KEYS.alice_public.clone());
let mut valid_signatures: HashSet<Fingerprint> = Default::default();
let plain = pk_decrypt(
CTEXT_SIGNED.as_bytes().to_vec(),
decrypt_keyring,
sig_check_keyring,
Some(&mut valid_signatures),
)
.await
.map_err(|err| println!("{:?}", err))
.unwrap();
assert_eq!(plain, CLEARTEXT);
assert_eq!(valid_signatures.len(), 1);
}
#[async_std::test]
async fn test_decrypt_no_sig_check() {
let mut keyring = Keyring::new();
keyring.add(KEYS.alice_secret.clone());
let empty_keyring = Keyring::new();
let mut valid_signatures: HashSet<Fingerprint> = Default::default();
let plain = pk_decrypt(
CTEXT_SIGNED.as_bytes().to_vec(),
keyring,
empty_keyring,
Some(&mut valid_signatures),
)
.await
.unwrap();
assert_eq!(plain, CLEARTEXT);
assert_eq!(valid_signatures.len(), 0);
}
#[async_std::test]
async fn test_decrypt_signed_no_key() {
// The validation does not have the public key of the signer.
let mut decrypt_keyring = Keyring::new();
decrypt_keyring.add(KEYS.bob_secret.clone());
let mut sig_check_keyring = Keyring::new();
sig_check_keyring.add(KEYS.bob_public.clone());
let mut valid_signatures: HashSet<Fingerprint> = Default::default();
let plain = pk_decrypt(
CTEXT_SIGNED.as_bytes().to_vec(),
decrypt_keyring,
sig_check_keyring,
Some(&mut valid_signatures),
)
.await
.unwrap();
assert_eq!(plain, CLEARTEXT);
assert_eq!(valid_signatures.len(), 0);
}
#[async_std::test]
async fn test_decrypt_unsigned() {
let mut decrypt_keyring = Keyring::new();
decrypt_keyring.add(KEYS.bob_secret.clone());
let sig_check_keyring = Keyring::new();
let mut valid_signatures: HashSet<Fingerprint> = Default::default();
let plain = pk_decrypt(
CTEXT_UNSIGNED.as_bytes().to_vec(),
decrypt_keyring,
sig_check_keyring,
Some(&mut valid_signatures),
)
.await
.unwrap();
assert_eq!(plain, CLEARTEXT);
assert_eq!(valid_signatures.len(), 0);
}
#[async_std::test]
async fn test_decrypt_signed_no_sigret() {
// Check decrypting signed cyphertext without providing the HashSet for signatures.
let mut decrypt_keyring = Keyring::new();
decrypt_keyring.add(KEYS.bob_secret.clone());
let mut sig_check_keyring = Keyring::new();
sig_check_keyring.add(KEYS.alice_public.clone());
let plain = pk_decrypt(
CTEXT_SIGNED.as_bytes().to_vec(),
decrypt_keyring,
sig_check_keyring,
None,
)
.await
.unwrap();
assert_eq!(plain, CLEARTEXT);
}
}