From 1691a261635aeff797a8415478d0c6a21e922b6a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damir=20Jeli=C4=87?= <poljar@termina.org.uk>
Date: Tue, 14 Jul 2020 17:04:08 +0200
Subject: [PATCH] crypto: Add initial Sas scaffolding.

---
 matrix_sdk_common/Cargo.toml              |   2 +-
 matrix_sdk_crypto/src/lib.rs              |   1 +
 matrix_sdk_crypto/src/verification/mod.rs |   2 +
 matrix_sdk_crypto/src/verification/sas.rs | 125 ++++++++++++++++++++++
 4 files changed, 129 insertions(+), 1 deletion(-)
 create mode 100644 matrix_sdk_crypto/src/verification/mod.rs
 create mode 100644 matrix_sdk_crypto/src/verification/sas.rs

diff --git a/matrix_sdk_common/Cargo.toml b/matrix_sdk_common/Cargo.toml
index 2bdc5f65..2ab514b0 100644
--- a/matrix_sdk_common/Cargo.toml
+++ b/matrix_sdk_common/Cargo.toml
@@ -15,7 +15,7 @@ instant = { version = "0.1.4", features = ["wasm-bindgen", "now"] }
 js_int = "0.1.8"
 
 [dependencies.ruma]
-git = "https://github.com/ruma/ruma"
+path = "/home/poljar/werk/priv/ruma/ruma"
 features = ["client-api"]
 rev = "c19bcaab"
 
diff --git a/matrix_sdk_crypto/src/lib.rs b/matrix_sdk_crypto/src/lib.rs
index cd5556bc..e7c26a06 100644
--- a/matrix_sdk_crypto/src/lib.rs
+++ b/matrix_sdk_crypto/src/lib.rs
@@ -32,6 +32,7 @@ mod machine;
 mod memory_stores;
 mod olm;
 mod store;
+mod verification;
 
 pub use device::{Device, TrustState};
 pub use error::{MegolmError, OlmError};
diff --git a/matrix_sdk_crypto/src/verification/mod.rs b/matrix_sdk_crypto/src/verification/mod.rs
new file mode 100644
index 00000000..c994a095
--- /dev/null
+++ b/matrix_sdk_crypto/src/verification/mod.rs
@@ -0,0 +1,2 @@
+#[allow(dead_code)]
+mod sas;
diff --git a/matrix_sdk_crypto/src/verification/sas.rs b/matrix_sdk_crypto/src/verification/sas.rs
new file mode 100644
index 00000000..01d07380
--- /dev/null
+++ b/matrix_sdk_crypto/src/verification/sas.rs
@@ -0,0 +1,125 @@
+use crate::Device;
+
+use matrix_sdk_common::events::key::verification::{
+    start::{StartEvent, StartEventContent},
+    accept::AcceptEvent,
+    HashAlgorithm, KeyAgreementProtocol, MessageAuthenticationCode, ShortAuthenticationString,
+    VerificationMethod,
+};
+use matrix_sdk_common::identifiers::{DeviceId, UserId};
+use matrix_sdk_common::uuid::Uuid;
+
+struct SasIds {
+    own_user_id: UserId,
+    own_device_id: DeviceId,
+    other_device: Device,
+}
+
+struct ProtocolDefinitions {
+    key_agreement_protocols: Vec<KeyAgreementProtocol>,
+    hashes: Vec<HashAlgorithm>,
+    message_auth_codes: Vec<MessageAuthenticationCode>,
+    short_auth_string: Vec<ShortAuthenticationString>,
+}
+
+struct AcceptedProtocols {
+    method: VerificationMethod,
+    key_agreement_protocol: KeyAgreementProtocol,
+    hash: HashAlgorithm,
+    message_auth_code: MessageAuthenticationCode,
+    short_auth_string: Vec<ShortAuthenticationString>
+}
+
+struct Sas<S> {
+    ids: SasIds,
+    verification_flow_id: Uuid,
+    protocol_definitions: ProtocolDefinitions,
+    state: S,
+}
+
+impl Sas<Created> {
+    fn new(own_user_id: UserId, own_device_id: DeviceId, other_device: Device) -> Sas<Created> {
+        Sas {
+            ids: SasIds {
+                own_user_id,
+                own_device_id,
+                other_device,
+            },
+            verification_flow_id: Uuid::new_v4(),
+
+            protocol_definitions: ProtocolDefinitions {
+                short_auth_string: vec![
+                    ShortAuthenticationString::Decimal,
+                    ShortAuthenticationString::Emoji,
+                ],
+                key_agreement_protocols: vec![KeyAgreementProtocol::Curve25519],
+                message_auth_codes: vec![MessageAuthenticationCode::HkdfHmacSha256],
+                hashes: vec![HashAlgorithm::Sha256],
+            },
+
+            state: Created {},
+        }
+    }
+
+    fn into_accepted(self, event: &AcceptEvent) -> Sas<Accepted> {
+        let content = &event.content;
+
+        Sas {
+            ids: self.ids,
+            verification_flow_id: self.verification_flow_id,
+            protocol_definitions: self.protocol_definitions,
+            state: Accepted {
+                commitment: content.commitment.clone(),
+                accepted_protocols: AcceptedProtocols {
+                   method: content.method,
+                   hash: content.hash,
+                   key_agreement_protocol: content.key_agreement_protocol,
+                   message_auth_code: content.message_authentication_code,
+                   short_auth_string: content.short_authentication_string.clone(),
+                }
+            },
+        }
+    }
+}
+
+struct Created {}
+
+struct Started {}
+
+impl Sas<Started> {
+    fn from_start_event(
+        own_user_id: UserId,
+        own_device_id: DeviceId,
+        other_device: Device,
+        event: &StartEvent,
+    ) -> Sas<Started> {
+        let content = if let StartEventContent::MSasV1(content) = &event.content {
+            content
+        } else {
+            panic!("Invalid sas version")
+        };
+
+        Sas {
+            ids: SasIds {
+                own_user_id,
+                own_device_id,
+                other_device,
+            },
+            verification_flow_id: Uuid::new_v4(),
+
+            protocol_definitions: ProtocolDefinitions {
+                short_auth_string: content.short_authentication_string.clone(),
+                key_agreement_protocols: content.key_agreement_protocols.clone(),
+                message_auth_codes: content.message_authentication_codes.clone(),
+                hashes: content.hashes.clone(),
+            },
+
+            state: Started {},
+        }
+    }
+}
+
+struct Accepted {
+    accepted_protocols: AcceptedProtocols,
+    commitment: String,
+}