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crypto: Finish up the key export feature.

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This commit is contained in:
Damir Jelić 2020-09-10 15:54:41 +02:00
parent 848156213b
commit e3f4c1849c
3 changed files with 249 additions and 37 deletions
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181
matrix_sdk_crypto/src/key_export.rs
View file

@ -26,24 +26,103 @@ use hmac::{Hmac, Mac, NewMac};
use pbkdf2::pbkdf2;
use sha2::{Sha256, Sha512};
use crate::olm::ExportedRoomKey;
const SALT_SIZE: usize = 16;
const IV_SIZE: usize = 16;
const MAC_SIZE: usize = 32;
const KEY_SIZE: usize = 32;
const VERSION: u8 = 1;
pub fn decode(input: impl AsRef<[u8]>) -> Result<Vec<u8>, DecodeError> {
const HEADER: &'static str = "-----BEGIN MEGOLM SESSION DATA-----";
const FOOTER: &'static str = "-----END MEGOLM SESSION DATA-----";
fn decode(input: impl AsRef<[u8]>) -> Result<Vec<u8>, DecodeError> {
decode_config(input, STANDARD_NO_PAD)
}
pub fn encode(input: impl AsRef<[u8]>) -> String {
fn encode(input: impl AsRef<[u8]>) -> String {
encode_config(input, STANDARD_NO_PAD)
}
pub fn encrypt(mut plaintext: &mut [u8], passphrase: &str, rounds: u32) -> String {
/// Try to decrypt a reader into a list of exported room keys.
///
/// # Arguments
///
/// * `passphrase` - The passphrase that was used to encrypt the exported keys.
///
/// # Examples
/// ```no_run
/// # use std::io::Cursor;
/// # use matrix_sdk_crypto::{OlmMachine, decrypt_key_export};
/// # use matrix_sdk_common::identifiers::user_id;
/// # use futures::executor::block_on;
/// # let alice = user_id!("@alice:example.org");
/// # let machine = OlmMachine::new(&alice, "DEVICEID".into());
/// # block_on(async {
/// # let export = Cursor::new("".to_owned());
/// let exported_keys = decrypt_key_export(export, "1234").unwrap();
/// machine.import_keys(exported_keys).await.unwrap();
/// # });
/// ```
pub fn decrypt_key_export(
mut input: impl Read,
passphrase: &str,
) -> Result<Vec<ExportedRoomKey>, DecodeError> {
let mut x: String = String::new();
input.read_to_string(&mut x).expect("Can't read string");
if !(x.trim_start().starts_with(HEADER) && x.trim_end().ends_with(FOOTER)) {
panic!("Invalid header/footer");
}
let payload: String = x
.lines()
.filter(|l| !(l.starts_with(HEADER) || l.starts_with(FOOTER)))
.collect();
Ok(serde_json::from_str(&decrypt_helper(&payload, passphrase)?).unwrap())
}
/// Encrypt the list of exported room keys using the given passphrase.
///
/// # Arguments
///
/// * `keys` - A list of sessions that should be encrypted.
///
/// * `passphrase` - The passphrase that will be used to encrypt the exported
/// room keys.
///
/// * `rounds` - The number of rounds that should be used for the key
/// derivation when the passphrase gets turned into an AES key. More rounds are
/// increasingly computationally intensive and as such help against bruteforce
/// attacks. Should be at least `10000`, while values in the `100000` ranges
/// should be preferred.
///
/// # Examples
/// ```no_run
/// # use matrix_sdk_crypto::{OlmMachine, encrypt_key_export};
/// # use matrix_sdk_common::identifiers::{user_id, room_id};
/// # use futures::executor::block_on;
/// # let alice = user_id!("@alice:example.org");
/// # let machine = OlmMachine::new(&alice, "DEVICEID".into());
/// # block_on(async {
/// let room_id = room_id!("!test:localhost");
/// let exported_keys = machine.export_keys(|s| s.room_id() == &room_id).await.unwrap();
/// let encrypted_export = encrypt_key_export(&exported_keys, "1234", 1);
/// # });
/// ```
pub fn encrypt_key_export(keys: &Vec<ExportedRoomKey>, passphrase: &str, rounds: u32) -> String {
let mut plaintext = serde_json::to_string(keys).unwrap().into_bytes();
let ciphertext = encrypt_helper(&mut plaintext, passphrase, rounds);
[HEADER.to_owned(), ciphertext, FOOTER.to_owned()].join("\n")
}
fn encrypt_helper(mut plaintext: &mut [u8], passphrase: &str, rounds: u32) -> String {
let mut salt = [0u8; SALT_SIZE];
let mut iv = [0u8; IV_SIZE];
let mut derived_keys = [0u8; KEY_SIZE * 2];
let version: u8 = 1;
getrandom(&mut salt).expect("Can't generate randomness");
getrandom(&mut iv).expect("Can't generate randomness");
@ -60,7 +139,7 @@ pub fn encrypt(mut plaintext: &mut [u8], passphrase: &str, rounds: u32) -> Strin
let mut payload: Vec<u8> = vec![];
payload.extend(&version.to_be_bytes());
payload.extend(&VERSION.to_be_bytes());
payload.extend(&salt);
payload.extend(&iv.to_be_bytes());
payload.extend(&rounds.to_be_bytes());
@ -75,7 +154,7 @@ pub fn encrypt(mut plaintext: &mut [u8], passphrase: &str, rounds: u32) -> Strin
encode(payload)
}
pub fn decrypt(ciphertext: &str, passphrase: &str) -> Result<String, DecodeError> {
fn decrypt_helper(ciphertext: &str, passphrase: &str) -> Result<String, DecodeError> {
let decoded = decode(ciphertext)?;
let mut decoded = Cursor::new(decoded);
@ -99,7 +178,7 @@ pub fn decrypt(ciphertext: &str, passphrase: &str) -> Result<String, DecodeError
let mut decoded = decoded.into_inner();
if version != 1u8 {
if version != VERSION {
panic!("Unsupported version")
}
@ -120,31 +199,31 @@ pub fn decrypt(ciphertext: &str, passphrase: &str) -> Result<String, DecodeError
#[cfg(test)]
mod test {
use indoc::indoc;
use proptest::prelude::*;
use std::io::Cursor;
use super::{decode, decrypt, encrypt};
use matrix_sdk_common::identifiers::room_id;
use matrix_sdk_test::async_test;
use super::{decode, decrypt_helper, decrypt_key_export, encrypt_helper, encrypt_key_export};
use crate::machine::test::get_prepared_machine;
const PASSPHRASE: &str = "1234";
const TEST_EXPORT: &str = indoc! {"
-----BEGIN MEGOLM SESSION DATA-----
AfukAbxZSTcn8SRQG/evmxHHzVGkkH7vmE2s0wWwebk+AAehIMVgIRmYAIPoxhSB4mKrsmoTbZuP4urLaWYPwCi22JhW5yvhGWp92vArL9gnN+2rB6VjDjzgR/OHkuLc
Tv5bWKNXPubrdWQujLmzQHnSqxPmNxpEbiDBLFIjuw2gKt8m8KKZGWcOk5sdtBVA7N8pje9urQE8e+rOT7q5yx4yeydtmZC5fb38/5YOn3E8hfpSC6jpXS+3jo/0so36
4c4l25CkkKWc07Ayhg9OjsEmDuHYuOO13r/TXojlfkaagBh3v8ZZb3+eWE4CeTV7jwVYbEy44vSKgACwLGdNX0/4TfjgfWBvOjF50h6YnprVD+vhbrG4NLg/TpdqiJ8p
pbp6t12vUMGULQudooXGvcsCoga6p9gS+pfxn9yhONBPU+pBFo+1Fnq80ZN8ErjVv58n3hLpH7YbvFwBPLBAj2h7dCHtj92E14jSgUvg+vRAAI5TwcZfuQwzH5qL6+Zh
1+pht9RsqplnbbdR32M3lypncAWgsUYtR/4wEBwlTSYCFW3GSm/Ow9XaWKF5RCZf9UTlOJ5veSkDZW61GCVLgsZj06Y+sji7IN7kGOBv4SfkYbhloLm0xPFCuQTbijqh
OCdzwH/lApCZflqBHLwAWsPuLrhgax99xs/QN9MIx8hh/pRc0pNNrBOgF1SJWQ/ChAuB7KbHcf4k1IFM0I4XH6u2GKpOxsQtulTulX3Sm+gCo0JBTO1DdYZPe7x0Enhl
dYojj6op4+HpJUw6Alh2g4SeCmZRcaux+0hwSCkuPRBX4fwgv+Qj0abgqATaLTGI6VXAP3ya4thaNNfEurj3+20b39VL6Bz8mW5g8aWo9DZ7/Ph6t042613wz9rKKrFv
ozKEqUX9Rbs01IknK2e8iakUKvzQjZ0ezs+XBy/0OKfyc+0KIj4vFvoTL9TePmOdBNNFQz91s21YDziE3fO8jJQLZGgf91ttCdtoouT2RAM1J7uIw0+4Ar0ytE2GiUgO
w/Zbo7M8CifIJ6CVM6F1dVdX7hj61lsbhzIV46xhscH6KszGioWD8zUaaXwt5b3Hrvsy4YbIRLhkVq1sZR/ETC+dqbSa/1cYngNwkoVspksK3JAaK1xVWGHFboXnxOtN
S+iWtIfWOIy9ExfA9+bz4y1s/VkruQAIIJJg/KH2bCsGMM+FHO3OaMOf4bvdnGH0SKpAk0WqVVZME6rTw5XqObqi5AF7Y+m8wyK87zdn3+n6JPBb7ROh/m4kuOcNvs9A
Gkhi8K4Q+/Ymeq6NNjkuvdKrlJxzdiwggCTA941158xnrs470QC0R/xDKfoZeFLWW6GhbwO6AuRy1vg4lkidrrD/zrczTMtOajhqL6CGARiufdbmByNVo1sybwTT/jOh
/divg/jY1RNY+IbEjOOWKnVcxrYURUFWjur4BgwkGBy9RovZRK6Co0gCXGwsdFrR9LG7jnGXiXm2fjGYDQghj8opC3wVtC7O0DQVrjDGRTZPOjoIgzvRomt7wbFosrww
Bw5RxiL5bA7bI9h1KuIPfR4+C2LjuRdnNSX0s+iQkz1cbwfGsa2pN1unzPwC0Gul6tciu2A32akfDQVzJrSCDahnoQXVZEEk0TdPY2oIZsEOmWZf94GQKr1IR7vJ37xj
iaYFKid+9F+ELlk2i6DQYDzXMacg55mWLuQkxC8MR5L9mPTtwoeVjbpbdzYctKdJ9KqeZTSh0qaSRnzuy3F7HnifwhkKI5JjyBQ5734gUmrikAfvtcBcpcd3ctX3+cwN
VwFxyQcwkTWNt4AQnzNVM3ZCxLEyMGqZ7XR3FQoxw8xTXJ4tSclI/g6vzKMVjHmuPRSMQj8PLhpICRnk5k50UmwS+rZTVqnHeJ+XF6JrEOYGgfOIVUUG5N+NCiBgvQKr
xa0ImLQXzJIdJqB2CLWIWytaqGSY4+Px2jSxQCIhl4PSBs5Ia1iBgZ3578Dp0DYz0caEzggDurLHrth1kVzC3zqm/D+uPBhF3iMOyp7gHuMOsCY1LKB2eyiizz1Hrhb4
ZBGGo15dC0KMP9uhmDeaijoH7YO5wReD427KNf5Z4kIFrgP0ebGr3sObZm74yJBlfnR0kKhFsQN7b/WthZIna7F/zIQaPYncitJqMTIgHXptrhaCV+c7AARs1pw/cnOQ
bH5evUA2zibgqaAOselrgnxbIqG2LQk84184b7V4Lg0+ebAjtTEVGqAiVVhydA7OCXETWfrS5le0W1/DAtv80K6KBMCkS33rKHUdTPru2fNGmo+angp9lO/ANQ==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-----END MEGOLM SESSION DATA-----
"};
@ -161,20 +240,56 @@ mod test {
assert!(decode(export).is_ok());
}
proptest! {
#[test]
fn proptest_encrypt_cycle(plaintext in prop::string::string_regex(".*").unwrap()) {
let mut plaintext_bytes = plaintext.clone().into_bytes();
let ciphertext = encrypt_helper(&mut plaintext_bytes, "test", 1);
let decrypted = decrypt_helper(&mut ciphertext.clone(), "test").unwrap();
prop_assert!(plaintext == decrypted);
}
}
#[test]
fn test_encrypt_decrypt() {
let data = "It's a secret to everybody";
let mut bytes = data.to_owned().into_bytes();
let encrypted = encrypt(&mut bytes, PASSPHRASE, 10);
let decrypted = decrypt(&encrypted, PASSPHRASE).unwrap();
let encrypted = encrypt_helper(&mut bytes, PASSPHRASE, 10);
let decrypted = decrypt_helper(&encrypted, PASSPHRASE).unwrap();
assert_eq!(data, decrypted);
}
// #[test]
// fn test_real_decrypt() {
// let export = export_wihtout_headers();
// decrypt(&export, PASSPHRASE).expect("Can't decrypt key export");
// }
#[async_test]
async fn test_session_encrypt() {
let (machine, _) = get_prepared_machine().await;
let room_id = room_id!("!test:localhost");
machine
.create_outnbound_group_session_with_defaults(&room_id)
.await
.unwrap();
let export = machine
.export_keys(|s| s.room_id() == &room_id)
.await
.unwrap();
assert!(!export.is_empty());
let encrypted = encrypt_key_export(&export, "1234", 1);
let decrypted = decrypt_key_export(Cursor::new(encrypted), "1234").unwrap();
assert_eq!(export, decrypted);
assert_eq!(machine.import_keys(decrypted).await.unwrap(), 0);
}
#[test]
fn test_real_decrypt() {
let reader = Cursor::new(TEST_EXPORT);
let imported = decrypt_key_export(reader, PASSPHRASE).expect("Can't decrypt key export");
assert!(!imported.is_empty())
}
}

1
matrix_sdk_crypto/src/lib.rs
View file

@ -41,6 +41,7 @@ pub use error::{MegolmError, OlmError};
pub use identities::{
Device, LocalTrust, OwnUserIdentity, ReadOnlyDevice, UserDevices, UserIdentities, UserIdentity,
};
pub use key_export::{decrypt_key_export, encrypt_key_export};
pub use machine::OlmMachine;
pub(crate) use olm::Account;
pub use olm::EncryptionSettings;

104
matrix_sdk_crypto/src/machine.rs
View file

@ -57,8 +57,8 @@ use super::{
UserIdentities, UserIdentity, UserSigningPubkey,
},
olm::{
Account, EncryptionSettings, GroupSessionKey, IdentityKeys, InboundGroupSession,
OlmMessage, OutboundGroupSession,
Account, EncryptionSettings, ExportedRoomKey, GroupSessionKey, IdentityKeys,
InboundGroupSession, OlmMessage, OutboundGroupSession,
},
requests::{IncomingResponse, OutgoingRequest, ToDeviceRequest},
store::{CryptoStore, MemoryStore, Result as StoreResult},
@ -1023,7 +1023,7 @@ impl OlmMachine {
}
#[cfg(test)]
async fn create_outnbound_group_session_with_defaults(
pub(crate) async fn create_outnbound_group_session_with_defaults(
&self,
room_id: &RoomId,
) -> OlmResult<()> {
@ -1529,6 +1529,102 @@ impl OlmMachine {
device_owner_identity,
})
}
/// Import the given room keys into our store.
///
/// # Arguments
///
/// * `exported_keys` - A list of previously exported keys that should be
/// imported into our store. If we already have a better version of a key
/// the key will *not* be imported.
///
/// Returns the number of sessions that were imported to the store.
///
/// # Examples
/// ```no_run
/// # use std::io::Cursor;
/// # use matrix_sdk_crypto::{OlmMachine, decrypt_key_export};
/// # use matrix_sdk_common::identifiers::user_id;
/// # use futures::executor::block_on;
/// # let alice = user_id!("@alice:example.org");
/// # let machine = OlmMachine::new(&alice, "DEVICEID".into());
/// # block_on(async {
/// # let export = Cursor::new("".to_owned());
/// let exported_keys = decrypt_key_export(export, "1234").unwrap();
/// machine.import_keys(exported_keys).await.unwrap();
/// # });
/// ```
pub async fn import_keys(&self, mut exported_keys: Vec<ExportedRoomKey>) -> StoreResult<usize> {
let mut sessions = Vec::new();
for key in exported_keys.drain(..) {
let session = InboundGroupSession::from_export(key)?;
// Only import the session if we didn't have this session or if it's
// a better version of the same session, that is the first known
// index is lower.
if let Some(existing_session) = self
.store
.get_inbound_group_session(
&session.room_id,
&session.sender_key,
session.session_id(),
)
.await?
{
if session.first_known_index().await < existing_session.first_known_index().await {
sessions.push(session)
}
} else {
sessions.push(session)
}
}
let num_sessions = sessions.len();
self.store.save_inbound_group_sessions(&sessions).await?;
Ok(num_sessions)
}
/// Export the keys that match the given predicate.
///
///
/// # Examples
///
/// ```no_run
/// # use matrix_sdk_crypto::{OlmMachine, encrypt_key_export};
/// # use matrix_sdk_common::identifiers::{user_id, room_id};
/// # use futures::executor::block_on;
/// # let alice = user_id!("@alice:example.org");
/// # let machine = OlmMachine::new(&alice, "DEVICEID".into());
/// # block_on(async {
/// let room_id = room_id!("!test:localhost");
/// let exported_keys = machine.export_keys(|s| s.room_id() == &room_id).await.unwrap();
/// let encrypted_export = encrypt_key_export(&exported_keys, "1234", 1);
/// # });
/// ```
pub async fn export_keys(
&self,
mut predicate: impl FnMut(&InboundGroupSession) -> bool,
) -> StoreResult<Vec<ExportedRoomKey>> {
let mut exported = Vec::new();
let mut sessions: Vec<InboundGroupSession> = self
.store
.get_inbound_group_sessions()
.await?
.drain(..)
.filter(|s| predicate(&s))
.collect();
for session in sessions.drain(..) {
let export = session.export().await;
exported.push(export);
}
Ok(exported)
}
}
#[cfg(test)]
@ -1623,7 +1719,7 @@ pub(crate) mod test {
content.deserialize().unwrap()
}
async fn get_prepared_machine() -> (OlmMachine, OneTimeKeys) {
pub(crate) async fn get_prepared_machine() -> (OlmMachine, OneTimeKeys) {
let machine = OlmMachine::new(&user_id(), &alice_device_id());
machine.account.update_uploaded_key_count(0);
let request = machine