Vendor HID (#446)

* introduces vendor HID

* updates workflows with new feature

* feature renaming and variant covering

src/ctap/main_hid.rs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use super::CtapState;
 use crate::clock::{ClockInt, CtapInstant};
 #[cfg(feature = "with_ctap1")]
 use crate::ctap::ctap1;
@@ -21,7 +20,7 @@ use crate::ctap::hid::ChannelID;
 use crate::ctap::hid::{
     CtapHid, CtapHidCommand, CtapHidError, HidPacket, HidPacketIterator, Message,
 };
-use crate::ctap::{Channel, TimedPermission};
+use crate::ctap::{Channel, CtapState, TimedPermission};
 use crate::env::Env;
 use embedded_time::duration::Milliseconds;
 

src/ctap/mod.rs

@@ -32,6 +32,8 @@ pub mod status_code;
 mod storage;
 mod timed_permission;
 mod token_state;
+#[cfg(feature = "vendor_hid")]
+pub mod vendor_hid;
 
 use self::client_pin::{ClientPin, PinPermission};
 use self::command::{
@@ -136,6 +138,7 @@ pub enum Transport {
     /// Corresponds to CTAP's USB transport.
     MainHid,
     /// No equivalent in CTAP, used for communication outside the specification.
+    #[cfg(feature = "vendor_hid")]
     VendorHid,
 }
 
@@ -151,6 +154,7 @@ pub enum Channel {
     /// Corresponds to CTAP's USB transport.
     MainHid(ChannelID),
     /// No equivalent in CTAP, used for communication outside the specification.
+    #[cfg(feature = "vendor_hid")]
     VendorHid(ChannelID),
 }
 

src/ctap/vendor_hid.rs

@@ -0,0 +1,174 @@
+// Copyright 2022 Google LLC
+//
+// 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.
+
+use crate::clock::CtapInstant;
+use crate::ctap::hid::{
+    CtapHid, CtapHidCommand, CtapHidError, HidPacket, HidPacketIterator, Message,
+};
+use crate::ctap::{Channel, CtapState};
+use crate::env::Env;
+
+/// Implements the non-standard command processing for HID.
+///
+/// Outside of the pure HID commands like INIT, only PING and CBOR commands are allowed.
+pub struct VendorHid {
+    hid: CtapHid,
+}
+
+impl VendorHid {
+    /// Instantiates a HID handler for CTAP1, CTAP2 and Wink.
+    pub fn new() -> Self {
+        let hid = CtapHid::new();
+        VendorHid { hid }
+    }
+
+    /// Processes an incoming USB HID packet, and returns an iterator for all outgoing packets.
+    pub fn process_hid_packet(
+        &mut self,
+        env: &mut impl Env,
+        packet: &HidPacket,
+        now: CtapInstant,
+        ctap_state: &mut CtapState,
+    ) -> HidPacketIterator {
+        if let Some(message) = self.hid.parse_packet(env, packet, now) {
+            let processed_message = self.process_message(env, message, now, ctap_state);
+            debug_ctap!(
+                env,
+                "Sending message through the second usage page: {:02x?}",
+                processed_message
+            );
+            CtapHid::split_message(processed_message)
+        } else {
+            HidPacketIterator::none()
+        }
+    }
+
+    /// Processes a message's commands that affect the protocol outside HID.
+    pub fn process_message(
+        &mut self,
+        env: &mut impl Env,
+        message: Message,
+        now: CtapInstant,
+        ctap_state: &mut CtapState,
+    ) -> Message {
+        let cid = message.cid;
+        match message.cmd {
+            // There are no custom CTAP1 commands.
+            CtapHidCommand::Msg => CtapHid::error_message(cid, CtapHidError::InvalidCmd),
+            // The CTAP2 processing function multiplexes internally.
+            CtapHidCommand::Cbor => {
+                let response =
+                    ctap_state.process_command(env, &message.payload, Channel::VendorHid(cid), now);
+                Message {
+                    cid,
+                    cmd: CtapHidCommand::Cbor,
+                    payload: response,
+                }
+            }
+            // Call Wink over the main HID.
+            CtapHidCommand::Wink => CtapHid::error_message(cid, CtapHidError::InvalidCmd),
+            // All other commands have already been processed, keep them as is.
+            _ => message,
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::ctap::hid::ChannelID;
+    use crate::env::test::TestEnv;
+
+    fn new_initialized() -> (VendorHid, ChannelID) {
+        let (hid, cid) = CtapHid::new_initialized();
+        (VendorHid { hid }, cid)
+    }
+
+    #[test]
+    fn test_process_hid_packet() {
+        let mut env = TestEnv::new();
+        let mut ctap_state = CtapState::new(&mut env, CtapInstant::new(0));
+        let (mut vendor_hid, cid) = new_initialized();
+
+        let mut ping_packet = [0x00; 64];
+        ping_packet[..4].copy_from_slice(&cid);
+        ping_packet[4..9].copy_from_slice(&[0x81, 0x00, 0x02, 0x99, 0x99]);
+
+        let mut response = vendor_hid.process_hid_packet(
+            &mut env,
+            &ping_packet,
+            CtapInstant::new(0),
+            &mut ctap_state,
+        );
+        assert_eq!(response.next(), Some(ping_packet));
+        assert_eq!(response.next(), None);
+    }
+
+    #[test]
+    fn test_process_hid_packet_empty() {
+        let mut env = TestEnv::new();
+        let mut ctap_state = CtapState::new(&mut env, CtapInstant::new(0));
+        let (mut vendor_hid, cid) = new_initialized();
+
+        let mut cancel_packet = [0x00; 64];
+        cancel_packet[..4].copy_from_slice(&cid);
+        cancel_packet[4..7].copy_from_slice(&[0x91, 0x00, 0x00]);
+
+        let mut response = vendor_hid.process_hid_packet(
+            &mut env,
+            &cancel_packet,
+            CtapInstant::new(0),
+            &mut ctap_state,
+        );
+        assert_eq!(response.next(), None);
+    }
+
+    #[test]
+    fn test_blocked_commands() {
+        let mut env = TestEnv::new();
+        let mut ctap_state = CtapState::new(&mut env, CtapInstant::new(0));
+        let (mut vendor_hid, cid) = new_initialized();
+
+        // Usually longer, but we don't parse them anyway.
+        let mut msg_packet = [0x00; 64];
+        msg_packet[..4].copy_from_slice(&cid);
+        msg_packet[4..7].copy_from_slice(&[0x83, 0x00, 0x00]);
+
+        let mut wink_packet = [0x00; 64];
+        wink_packet[..4].copy_from_slice(&cid);
+        wink_packet[4..7].copy_from_slice(&[0x88, 0x00, 0x00]);
+
+        let mut error_packet = [0x00; 64];
+        error_packet[..4].copy_from_slice(&cid);
+        error_packet[4..8].copy_from_slice(&[0xBF, 0x00, 0x01, 0x01]);
+
+        let mut response = vendor_hid.process_hid_packet(
+            &mut env,
+            &msg_packet,
+            CtapInstant::new(0),
+            &mut ctap_state,
+        );
+        assert_eq!(response.next(), Some(error_packet));
+        assert_eq!(response.next(), None);
+
+        let mut response = vendor_hid.process_hid_packet(
+            &mut env,
+            &wink_packet,
+            CtapInstant::new(0),
+            &mut ctap_state,
+        );
+        assert_eq!(response.next(), Some(error_packet));
+        assert_eq!(response.next(), None);
+    }
+}