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crypto: Add initial SAS canceling.

master
Damir Jelić 2020-07-27 13:16:56 +02:00
parent 7128505768
commit da3734ffc7
1 changed files with 69 additions and 38 deletions
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107
matrix_sdk_crypto/src/verification/sas.rs
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@ -12,25 +12,29 @@
// See the License for the specific language governing permissions and
// limitations under the License.
use std::mem;
use std::sync::{Arc, Mutex};
use olm_rs::sas::OlmSas;
use matrix_sdk_common::events::{
key::verification::{
accept::AcceptEventContent,
cancel::CancelCode,
key::KeyEventContent,
mac::MacEventContent,
start::{MSasV1Content, MSasV1ContentOptions, StartEventContent},
HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
VerificationMethod,
},
AnyToDeviceEvent, AnyToDeviceEventContent, ToDeviceEvent,
use std::{
mem,
sync::{Arc, Mutex},
};
use olm_rs::{sas::OlmSas, utility::OlmUtility};
use matrix_sdk_common::{
events::{
key::verification::{
accept::AcceptEventContent,
cancel::{CancelCode, CancelEventContent},
key::KeyEventContent,
mac::MacEventContent,
start::{MSasV1Content, MSasV1ContentOptions, StartEventContent},
HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode,
ShortAuthenticationString, VerificationMethod,
},
AnyToDeviceEvent, AnyToDeviceEventContent, ToDeviceEvent,
},
identifiers::{DeviceId, UserId},
uuid::Uuid,
};
use matrix_sdk_common::identifiers::{DeviceId, UserId};
use matrix_sdk_common::uuid::Uuid;
use super::{get_decimal, get_emoji, get_mac_content, receive_mac_event, SasIds};
use crate::{Account, Device};
@ -44,6 +48,15 @@ struct Sas {
}
impl Sas {
const KEY_AGREEMENT_PROTOCOLS: &'static [KeyAgreementProtocol] =
&[KeyAgreementProtocol::Curve25519HkdfSha256];
const HASHES: &'static [HashAlgorithm] = &[HashAlgorithm::Sha256];
const MACS: &'static [MessageAuthenticationCode] = &[MessageAuthenticationCode::HkdfHmacSha256];
const STRINGS: &'static [ShortAuthenticationString] = &[
ShortAuthenticationString::Decimal,
ShortAuthenticationString::Emoji,
];
/// Get our own user id.
fn user_id(&self) -> &UserId {
self.account.user_id()
@ -90,13 +103,13 @@ impl Sas {
account: Account,
other_device: Device,
event: &ToDeviceEvent<StartEventContent>,
) -> Sas {
let inner = InnerSas::from_start_event(account.clone(), other_device.clone(), event);
Sas {
) -> Result<Sas, CancelEventContent> {
let inner = InnerSas::from_start_event(account.clone(), other_device.clone(), event)?;
Ok(Sas {
inner: Arc::new(Mutex::new(inner)),
account,
other_device,
}
})
}
fn accept(&self) -> Option<AcceptEventContent> {
@ -156,7 +169,7 @@ enum InnerSas {
impl InnerSas {
fn start(account: Account, other_device: Device) -> (InnerSas, StartEventContent) {
let sas = SasState::<Created>::new(account, other_device);
let content = sas.get_start_event();
let content = sas.as_content();
(InnerSas::Created(sas), content)
}
@ -164,16 +177,16 @@ impl InnerSas {
account: Account,
other_device: Device,
event: &ToDeviceEvent<StartEventContent>,
) -> InnerSas {
) -> Result<InnerSas, CancelEventContent> {
match SasState::<Started>::from_start_event(account, other_device, event) {
Ok(s) => InnerSas::Started(s),
Err(s) => InnerSas::Canceled(s),
Ok(s) => Ok(InnerSas::Started(s)),
Err(s) => Err(s.as_content()),
}
}
fn accept(&self) -> Option<AcceptEventContent> {
if let InnerSas::Started(s) = self {
Some(s.get_accept_content())
Some(s.as_content())
} else {
None
}
@ -347,6 +360,7 @@ struct Created {
/// The initial SAS state if the other side started the SAS verification.
#[derive(Clone, Debug)]
struct Started {
commitment: String,
protocol_definitions: MSasV1Content,
}
@ -462,7 +476,7 @@ impl SasState<Created> {
/// Get the content for the start event.
///
/// The content needs to be sent to the other device.
fn get_start_event(&self) -> StartEventContent {
fn as_content(&self) -> StartEventContent {
StartEventContent::MSasV1(
MSasV1Content::new(self.state.protocol_definitions.clone())
.expect("Invalid initial protocol definitions."),
@ -513,8 +527,15 @@ impl SasState<Started> {
event: &ToDeviceEvent<StartEventContent>,
) -> Result<SasState<Started>, SasState<Canceled>> {
if let StartEventContent::MSasV1(content) = &event.content {
let sas = OlmSas::new();
let utility = OlmUtility::new();
let json_content = cjson::to_string(&event.content).expect("Can't serialize content");
let pubkey = sas.public_key();
let commitment = utility.sha256_utf8_msg(&format!("{}{}", pubkey, json_content));
let sas = SasState {
inner: Arc::new(Mutex::new(OlmSas::new())),
inner: Arc::new(Mutex::new(sas)),
ids: SasIds {
account,
@ -525,6 +546,7 @@ impl SasState<Started> {
state: Arc::new(Started {
protocol_definitions: content.clone(),
commitment,
}),
};
@ -571,12 +593,11 @@ impl SasState<Started> {
/// This should be sent out automatically if the SAS verification flow has
/// been started because of a
/// m.key.verification.request -> m.key.verification.ready flow.
fn get_accept_content(&self) -> AcceptEventContent {
fn as_content(&self) -> AcceptEventContent {
AcceptEventContent {
method: VerificationMethod::MSasV1,
transaction_id: self.verification_flow_id.to_string(),
// TODO calculate the commitment.
commitment: "".to_owned(),
commitment: self.state.commitment.clone(),
hash: HashAlgorithm::Sha256,
key_agreement_protocol: KeyAgreementProtocol::Curve25519HkdfSha256,
message_authentication_code: MessageAuthenticationCode::HkdfHmacSha256,
@ -600,7 +621,7 @@ impl SasState<Started> {
self,
event: &mut ToDeviceEvent<KeyEventContent>,
) -> SasState<KeyReceived> {
let accepted_protocols: AcceptedProtocols = self.get_accept_content().into();
let accepted_protocols: AcceptedProtocols = self.as_content().into();
self.inner
.lock()
.unwrap()
@ -877,6 +898,16 @@ impl Canceled {
}
}
impl SasState<Canceled> {
fn as_content(&self) -> CancelEventContent {
CancelEventContent {
transaction_id: self.verification_flow_id.to_string(),
reason: self.state.reason.to_string(),
code: self.state.cancel_code.clone(),
}
}
}
#[cfg(test)]
mod test {
use std::convert::TryFrom;
@ -936,7 +967,7 @@ mod test {
let alice_sas = SasState::<Created>::new(alice.clone(), bob_device);
let start_content = alice_sas.get_start_event();
let start_content = alice_sas.as_content();
let event = wrap_to_device_event(alice_sas.user_id(), start_content);
let bob_sas = SasState::<Started>::from_start_event(bob.clone(), alice_device, &event);
@ -953,7 +984,7 @@ mod test {
async fn sas_accept() {
let (alice, bob) = get_sas_pair().await;
let event = wrap_to_device_event(bob.user_id(), bob.get_accept_content());
let event = wrap_to_device_event(bob.user_id(), bob.as_content());
alice.into_accepted(&event);
}
@ -962,7 +993,7 @@ mod test {
async fn sas_key_share() {
let (alice, bob) = get_sas_pair().await;
let event = wrap_to_device_event(bob.user_id(), bob.get_accept_content());
let event = wrap_to_device_event(bob.user_id(), bob.as_content());
let alice: SasState<Accepted> = alice.into_accepted(&event);
let mut event = wrap_to_device_event(alice.user_id(), alice.get_key_content());
@ -981,7 +1012,7 @@ mod test {
async fn sas_full() {
let (alice, bob) = get_sas_pair().await;
let event = wrap_to_device_event(bob.user_id(), bob.get_accept_content());
let event = wrap_to_device_event(bob.user_id(), bob.as_content());
let alice: SasState<Accepted> = alice.into_accepted(&event);
let mut event = wrap_to_device_event(alice.user_id(), alice.get_key_content());
@ -1021,7 +1052,7 @@ mod test {
let (alice, content) = Sas::start(alice, bob_device);
let event = wrap_to_device_event(alice.user_id(), content);
let bob = Sas::from_start_event(bob, alice_device, &event);
let bob = Sas::from_start_event(bob, alice_device, &event).unwrap();
let event = wrap_to_device_event(bob.user_id(), bob.accept().unwrap());
let content = alice.receive_event(&mut AnyToDeviceEvent::KeyVerificationAccept(event));