chore(core/rust): Add uPy-exported io_usb_start fn

core/embed/rust/build.rs

@@ -129,6 +129,7 @@ fn generate_micropython_bindings() {
         .allowlist_function("trezor_obj_get_ll_checked")
         .allowlist_function("trezor_obj_get_ull_checked")
         .allowlist_function("trezor_obj_str_from_rom_text")
+        .allowlist_var("mp_const_empty_tuple_obj")
         // buffer
         .allowlist_function("mp_get_buffer")
         .allowlist_var("MP_BUFFER_READ")

core/embed/rust/librust.h

@@ -1,5 +1,7 @@
 #include "librust_qstr.h"
 
+mp_obj_t io_usb_start(mp_obj_t serial_number);
+
 mp_obj_t protobuf_type_for_name(mp_obj_t name);
 mp_obj_t protobuf_type_for_wire(mp_obj_t wire_id);
 mp_obj_t protobuf_decode(mp_obj_t buf, mp_obj_t def,

core/embed/rust/src/io.rs

@@ -1,7 +1,16 @@
+use core::ops::RangeFrom;
+
+use cstr_core::{cstr, CStr};
+
 use crate::{
     error::Error,
+    micropython::{buffer::Buffer, obj::Obj},
     time::{Duration, Instant},
-    trezorhal::usb::{usb_is_ready_to_read, usb_is_ready_to_write, IfaceTicket},
+    trezorhal::usb::{
+        usb_is_ready_to_read, usb_is_ready_to_write, usb_open, IfaceTicket, UsbConfig, UsbError,
+        WebUsbConfig,
+    },
+    util,
     util::wait_in_busy_loop,
 };
 
@@ -87,3 +96,190 @@ pub fn poll_io(resources: &[Resource], timeout: Duration) -> Result<Event, Error
         }
     }
 }
+
+extern "C" fn io_usb_start(serial_number: Obj) -> Obj {
+    #[cfg(feature = "ui_debug")]
+    use crate::trezorhal::usb::VcpConfig;
+
+    #[cfg(not(feature = "bitcoin_only"))]
+    use crate::trezorhal::usb::HidConfig;
+
+    // SAFETY:
+    // In this function we often take mut refs to static mut buffers. This requires
+    // an unsafe block. Safety rationale:
+    //  - We are in a single-threaded context.
+    //  - `io_usb_start` is required to be called with USB turned off.
+    //  - Underlying USB stack is required to manage the buffers on its own,
+    //    guarding i.e. against escaping of stale buffer content.
+
+    const UDP_PORT: u16 = 0;
+    const WIRE_PORT_OFFSET: u16 = 0;
+    const DEBUGLINK_PORT_OFFSET: u16 = 1;
+    const WEBAUTHN_PORT_OFFSET: u16 = 2;
+    const VCP_PORT_OFFSET: u16 = 3;
+
+    fn usb_config(serial_number: &CStr) -> UsbConfig {
+        UsbConfig {
+            vendor_id: 0x1209,
+            product_id: 0x53C1,
+            release_num: 0x0200,
+            manufacturer: cstr!("SatoshiLabs"),
+            product: cstr!("TREZOR"),
+            serial_number: set_global_serial_number(serial_number),
+            interface: cstr!("TREZOR Interface"),
+            usb21_landing: false,
+            ..UsbConfig::default()
+        }
+    }
+
+    fn create_wire_iface(ids: &mut RangeFrom<u8>) -> WebUsbConfig {
+        static mut WIRE_RX_BUFFER: [u8; 64] = [0; 64];
+
+        let id = ids.next().unwrap();
+        WebUsbConfig {
+            rx_buffer: unsafe { &mut WIRE_RX_BUFFER },
+            iface_num: id,
+            ep_in: 0x81 + id,
+            ep_out: 0x01 + id,
+            emu_port: UDP_PORT + WIRE_PORT_OFFSET,
+        }
+    }
+
+    #[cfg(feature = "ui_debug")]
+    fn create_debug_iface(ids: &mut RangeFrom<u8>) -> WebUsbConfig {
+        static mut DEBUG_RX_BUFFER: [u8; 64] = [0; 64];
+
+        let id = ids.next().unwrap();
+        WebUsbConfig {
+            rx_buffer: unsafe { &mut DEBUG_RX_BUFFER },
+            iface_num: id,
+            ep_in: 0x81 + id,
+            ep_out: 0x01 + id,
+            emu_port: UDP_PORT + DEBUGLINK_PORT_OFFSET,
+        }
+    }
+
+    #[cfg(not(feature = "bitcoin_only"))]
+    fn create_webauthn_iface(ids: &mut RangeFrom<u8>) -> HidConfig {
+        static mut WEBAUTHN_RX_BUFFER: [u8; 64] = [0; 64];
+
+        let id = ids.next().unwrap();
+        HidConfig {
+            report_desc: &[
+                0x06, 0xd0, 0xf1, // USAGE_PAGE (FIDO Alliance)
+                0x09, 0x01, // USAGE (U2F HID Authenticator Device)
+                0xa1, 0x01, // COLLECTION (Application)
+                0x09, 0x20, // USAGE (Input Report Data)
+                0x15, 0x00, // LOGICAL_MINIMUM (0)
+                0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
+                0x75, 0x08, // REPORT_SIZE (8)
+                0x95, 0x40, // REPORT_COUNT (64)
+                0x81, 0x02, // INPUT (Data,Var,Abs)
+                0x09, 0x21, // USAGE (Output Report Data)
+                0x15, 0x00, // LOGICAL_MINIMUM (0)
+                0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
+                0x75, 0x08, // REPORT_SIZE (8)
+                0x95, 0x40, // REPORT_COUNT (64)
+                0x91, 0x02, // OUTPUT (Data,Var,Abs)
+                0xc0, // END_COLLECTION
+            ],
+            rx_buffer: unsafe { &mut WEBAUTHN_RX_BUFFER },
+            iface_num: id,
+            ep_in: 0x81 + id,
+            ep_out: 0x01 + id,
+            emu_port: UDP_PORT + WEBAUTHN_PORT_OFFSET,
+        }
+    }
+
+    #[cfg(feature = "ui_debug")]
+    fn create_vcp_iface(ids: &mut RangeFrom<u8>) -> VcpConfig {
+        static mut VCP_RX_BUFFER: [u8; 1024] = [0; 1024];
+        static mut VCP_TX_BUFFER: [u8; 1024] = [0; 1024];
+        static mut VCP_RX_PACKET: [u8; 64] = [0; 64];
+        static mut VCP_TX_PACKET: [u8; 64] = [0; 64];
+
+        let id = ids.next().unwrap();
+        let id_data = ids.next().unwrap();
+        VcpConfig {
+            rx_buffer: unsafe { &mut VCP_RX_BUFFER },
+            tx_buffer: unsafe { &mut VCP_TX_BUFFER },
+            rx_packet: unsafe { &mut VCP_RX_PACKET },
+            tx_packet: unsafe { &mut VCP_TX_PACKET },
+            rx_intr_fn: None, // Use pendsv_kbd_intr here.
+            rx_intr_byte: 3,  // Ctrl-C
+            iface_num: id,
+            data_iface_num: id_data,
+            ep_in: 0x81 + id,
+            ep_out: 0x01 + id,
+            ep_cmd: 0x81 + id_data,
+            emu_port: UDP_PORT + VCP_PORT_OFFSET,
+        }
+    }
+
+    fn set_global_serial_number(sn: &CStr) -> &'static CStr {
+        static mut GLOBAL_BUFFER: [u8; 64] = [0; 64];
+
+        // SAFETY: We are in a single threaded context, so the only possible race on
+        // `GLOBAL_BUFFER` is with the USB stack. We should take care to only call
+        // `set_global_serial_number` with the USB stopped.
+        unsafe {
+            let sn_nul = sn.to_bytes_with_nul();
+
+            // Panics if `sn_nul` is bigger then `GLOBAL_BUFFER`.
+            GLOBAL_BUFFER[..sn_nul.len()].copy_from_slice(sn_nul);
+
+            CStr::from_bytes_with_nul_unchecked(&GLOBAL_BUFFER[..sn_nul.len()])
+        }
+    }
+
+    let block = || {
+        let serial_number: Buffer = serial_number.try_into()?;
+        let serial_number =
+            CStr::from_bytes_with_nul(&serial_number).map_err(|_| Error::TypeError)?;
+
+        let mut ids = 0u8..; // Iterator of interface IDS.
+        let mut usb = usb_config(serial_number);
+
+        // Create the interfaces we use and add them to the config. Note that the order
+        // matters.
+
+        let wire_id = create_wire_iface(&mut ids).add(&mut usb)?.iface_num();
+
+        #[cfg(feature = "ui_debug")]
+        let debug_id = Some(create_debug_iface(&mut ids).add(&mut usb)?.iface_num());
+        #[cfg(not(feature = "ui_debug"))]
+        let debug_id: Option<u8> = None;
+
+        #[cfg(feature = "bitcoin_only")]
+        let webauthn_id: Option<u8> = None;
+        #[cfg(not(feature = "bitcoin_only"))]
+        let webauthn_id = Some(create_webauthn_iface(&mut ids).add(&mut usb)?.iface_num());
+
+        #[cfg(feature = "ui_debug")]
+        {
+            create_vcp_iface(&mut ids).add(&mut usb)?;
+            // TODO: Enable MicroPython VCP support.
+        }
+
+        // Convert used interface IDs to MicroPython objects.
+        let wire_id_obj = Obj::try_from(wire_id as u32)?;
+        let debug_id_obj = Obj::from(debug_id.map(Obj::try_from).transpose()?);
+        let webauthn_id_obj = Obj::from(webauthn_id.map(Obj::try_from).transpose()?);
+        let tuple = Obj::try_from((wire_id_obj, debug_id_obj, webauthn_id_obj))?;
+
+        // Initialize the USB and start the configured interfaces.
+        usb_open(usb)?;
+
+        Ok(tuple)
+    };
+    unsafe { util::try_or_raise(block) }
+}
+
+impl From<UsbError> for Error {
+    fn from(usb: UsbError) -> Self {
+        match usb {
+            UsbError::FailedToAddInterface => Error::ValueError(cstr!("Failed to add interface")),
+            UsbError::InterfaceNotFound => Error::ValueError(cstr!("Interface not found")),
+        }
+    }
+}

core/embed/rust/src/lib.rs

@@ -22,7 +22,7 @@ mod util;
 #[cfg(not(feature = "test"))]
 #[panic_handler]
 fn panic(_info: &core::panic::PanicInfo) -> ! {
-    use cstr_core::CStr;
+    use cstr_core::cstr;
 
     // Although it would be ideal to use the original error message, ignoring it
     // lets us avoid the `fmt` machinery and its code size and is also important for
@@ -30,9 +30,8 @@ fn panic(_info: &core::panic::PanicInfo) -> ! {
     // should also avoid printing "panic" or "rust" on the user screen to avoid any
     // confusion.
 
-    // SAFETY: Safe because we are passing in \0-terminated literals.
-    let empty = unsafe { CStr::from_bytes_with_nul_unchecked(b"\0") };
-    let msg = unsafe { CStr::from_bytes_with_nul_unchecked(b"rs\0") };
+    let empty = cstr!("");
+    let msg = cstr!("rs");
 
     // TODO: Ideally we would take the file and line info out of
     // `PanicInfo::location()`.

core/embed/rust/src/micropython/ffi.rs

@@ -1,5 +1,6 @@
+#![allow(dead_code)]
 #![allow(non_camel_case_types)]
 #![allow(non_upper_case_globals)]
-#![allow(dead_code)]
+#![allow(unsafe_op_in_unsafe_fn)]
 
 include!(concat!(env!("OUT_DIR"), "/micropython.rs"));

core/embed/rust/src/micropython/obj.rs

@@ -305,6 +305,48 @@ impl TryFrom<(Obj, Obj)> for Obj {
     }
 }
 
+impl From<()> for Obj {
+    fn from(_value: ()) -> Self {
+        // micropython/py/obj.h
+        // #define mp_const_empty_tuple (MP_OBJ_FROM_PTR(&mp_const_empty_tuple_obj))
+        unsafe {
+            let empty_tuple_ptr = &ffi::mp_const_empty_tuple_obj as *const _ as *mut _;
+            Obj::from_ptr(empty_tuple_ptr)
+        }
+    }
+}
+
+// TODO: WARNING: while rebasing I chose randomly to ignore this implementation
+// and use the abovementioned
+
+// impl TryFrom<(Obj, Obj)> for Obj {
+//     type Error = Error;
+
+//     fn try_from(value: (Obj, Obj)) -> Result<Self, Self::Error> {
+//         // SAFETY: `mp_obj_new_tuple` does not retain pointer to `items`,
+// expects to         // find `items.len()` elements and does not modify them.
+//         // EXCEPTION: Will raise if allocation fails.
+//         catch_exception(|| unsafe {
+//             let items = [value.0, value.1];
+//             ffi::mp_obj_new_tuple(items.len(), items.as_ptr())
+//         })
+//     }
+// }
+
+impl TryFrom<(Obj, Obj, Obj)> for Obj {
+    type Error = Error;
+
+    fn try_from(value: (Obj, Obj, Obj)) -> Result<Self, Self::Error> {
+        // SAFETY: `mp_obj_new_tuple` does not retain pointer to `items`, expects to
+        // find `items.len()` elements and does not modify them.
+        // EXCEPTION: Will raise if allocation fails.
+        catch_exception(|| unsafe {
+            let items = [value.0, value.1, value.2];
+            ffi::mp_obj_new_tuple(items.len(), items.as_ptr())
+        })
+    }
+}
+
 //
 // # Additional conversions based on the methods above.
 //

core/embed/rust/src/protobuf/error.rs

@@ -1,31 +1,30 @@
-use cstr_core::CStr;
+use cstr_core::cstr;
 
 use crate::{error::Error, micropython::qstr::Qstr};
 
 // XXX const version of `from_bytes_with_nul_unchecked` is nightly-only.
 
 pub fn experimental_not_enabled() -> Error {
-    let msg =
-        unsafe { CStr::from_bytes_with_nul_unchecked(b"Experimental features are disabled.\0") };
+    let msg = cstr!("Experimental features are disabled");
     Error::ValueError(msg)
 }
 
 pub fn unknown_field_type() -> Error {
-    let msg = unsafe { CStr::from_bytes_with_nul_unchecked(b"Unknown field type.\0") };
+    let msg = cstr!("Unknown field type");
     Error::ValueError(msg)
 }
 
 pub fn missing_required_field(field: Qstr) -> Error {
-    let msg = unsafe { CStr::from_bytes_with_nul_unchecked(b"Missing required field\0") };
+    let msg = cstr!("Missing required field");
     Error::ValueErrorParam(msg, field.into())
 }
 
 pub fn invalid_value(field: Qstr) -> Error {
-    let msg = unsafe { CStr::from_bytes_with_nul_unchecked(b"Invalid value for field\0") };
+    let msg = cstr!("Invalid value for field");
     Error::ValueErrorParam(msg, field.into())
 }
 
 pub fn end_of_buffer() -> Error {
-    let msg = unsafe { CStr::from_bytes_with_nul_unchecked(b"End of buffer.\0") };
+    let msg = cstr!("End of buffer");
     Error::ValueError(msg)
 }

core/embed/rust/src/trezorhal/usb.rs

@@ -107,19 +107,19 @@ pub fn usb_close() {
 const MAX_INTERFACE_COUNT: usize = 4;
 
 #[derive(Default)]
-pub struct UsbConfig<'a> {
+pub struct UsbConfig {
     pub vendor_id: u16,
     pub product_id: u16,
     pub release_num: u16,
     pub manufacturer: &'static CStr,
     pub product: &'static CStr,
     pub interface: &'static CStr,
-    pub serial_number: &'a CStr,
+    pub serial_number: &'static CStr,
     pub usb21_landing: bool,
     pub interfaces: Vec<IfaceConfig, MAX_INTERFACE_COUNT>,
 }
 
-impl UsbConfig<'_> {
+impl UsbConfig {
     fn as_dev_info(&self) -> ffi::usb_dev_info_t {
         ffi::usb_dev_info_t {
             device_class: 0,
@@ -131,8 +131,7 @@ impl UsbConfig<'_> {
             manufacturer: self.manufacturer.as_ptr(),
             product: self.product.as_ptr(),
             interface: self.interface.as_ptr(),
-            // Because we set the SN dynamically, we need to copy it to the static storage first.
-            serial_number: set_global_serial_number(self.serial_number).as_ptr(),
+            serial_number: self.serial_number.as_ptr(),
             usb21_enabled: secbool::TRUE,
             usb21_landing: if self.usb21_landing {
                 secbool::TRUE
@@ -151,6 +150,15 @@ pub enum IfaceTicket {
     WebUsb(u8),
 }
 
+impl IfaceTicket {
+    pub fn iface_num(&self) -> u8 {
+        match self {
+            IfaceTicket::Hid(iface_num) => *iface_num,
+            IfaceTicket::WebUsb(iface_num) => *iface_num,
+        }
+    }
+}
+
 pub enum IfaceConfig {
     WebUsb(WebUsbConfig),
     Hid(HidConfig),
@@ -383,130 +391,3 @@ impl VcpConfig {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use cstr_core::cstr;
-
-    use super::*;
-
-    #[test]
-    fn test_usb() {
-        // Example port of usb.py.
-
-        const UDP_PORT: u16 = 0;
-        const WIRE_PORT_OFFSET: u16 = 0;
-        const DEBUGLINK_PORT_OFFSET: u16 = 1;
-        const WEBAUTHN_PORT_OFFSET: u16 = 2;
-        const VCP_PORT_OFFSET: u16 = 3;
-
-        let mut iface_iter = 0u8..;
-
-        const ENABLE_IFACE_DEBUG: bool = true;
-        const ENABLE_IFACE_WEBAUTHN: bool = true;
-        const ENABLE_IFACE_VCP: bool = true;
-
-        let mut config = UsbConfig {
-            vendor_id: 0x1209,
-            product_id: 0x53C1,
-            release_num: 0x0200,
-            manufacturer: cstr!("SatoshiLabs"),
-            product: cstr!("TREZOR"),
-            serial_number: cstr!(""),
-            interface: cstr!("TREZOR Interface"),
-            usb21_landing: false,
-            ..UsbConfig::default()
-        };
-
-        let id_wire = iface_iter.next().unwrap();
-        let iface_wire = WebUsbConfig {
-            rx_buffer: &mut [0; 64],
-            iface_num: id_wire,
-            ep_in: 0x81 + id_wire,
-            ep_out: 0x01 + id_wire,
-            emu_port: UDP_PORT + WIRE_PORT_OFFSET,
-        };
-        let ticket_wire = iface_wire.add(&mut config).unwrap();
-
-        if ENABLE_IFACE_DEBUG {
-            let id_debug = iface_iter.next().unwrap();
-            let iface_debug = WebUsbConfig {
-                rx_buffer: &mut [0; 64],
-                iface_num: id_debug,
-                ep_in: 0x81 + id_debug,
-                ep_out: 0x01 + id_debug,
-                emu_port: UDP_PORT + DEBUGLINK_PORT_OFFSET,
-            };
-            let ticket_debug = iface_debug.add(&mut config).unwrap();
-        }
-
-        if ENABLE_IFACE_WEBAUTHN {
-            let id_webauthn = iface_iter.next().unwrap();
-            let iface_webauthn = HidConfig {
-                report_desc: &[
-                    0x06, 0xd0, 0xf1, // USAGE_PAGE (FIDO Alliance)
-                    0x09, 0x01, // USAGE (U2F HID Authenticator Device)
-                    0xa1, 0x01, // COLLECTION (Application)
-                    0x09, 0x20, // USAGE (Input Report Data)
-                    0x15, 0x00, // LOGICAL_MINIMUM (0)
-                    0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
-                    0x75, 0x08, // REPORT_SIZE (8)
-                    0x95, 0x40, // REPORT_COUNT (64)
-                    0x81, 0x02, // INPUT (Data,Var,Abs)
-                    0x09, 0x21, // USAGE (Output Report Data)
-                    0x15, 0x00, // LOGICAL_MINIMUM (0)
-                    0x26, 0xff, 0x00, // LOGICAL_MAXIMUM (255)
-                    0x75, 0x08, // REPORT_SIZE (8)
-                    0x95, 0x40, // REPORT_COUNT (64)
-                    0x91, 0x02, // OUTPUT (Data,Var,Abs)
-                    0xc0, // END_COLLECTION
-                ],
-                rx_buffer: &mut [0; 64],
-                iface_num: id_webauthn,
-                ep_in: 0x81 + id_webauthn,
-                ep_out: 0x01 + id_webauthn,
-                emu_port: UDP_PORT + WEBAUTHN_PORT_OFFSET,
-            };
-            let ticket_webauthn = iface_webauthn.add(&mut config).unwrap();
-        }
-
-        if ENABLE_IFACE_VCP {
-            let id_vcp = iface_iter.next().unwrap();
-            let id_vcp_data = iface_iter.next().unwrap();
-            let iface_vcp = VcpConfig {
-                rx_buffer: &mut [0; 1024],
-                tx_buffer: &mut [0; 1024],
-                rx_packet: &mut [0; 64],
-                tx_packet: &mut [0; 64],
-                rx_intr_fn: None, // Use pendsv_kbd_intr here.
-                rx_intr_byte: 3,  // Ctrl-C
-                iface_num: id_vcp,
-                data_iface_num: id_vcp_data,
-                ep_in: 0x81 + id_vcp,
-                ep_out: 0x01 + id_vcp,
-                ep_cmd: 0x81 + id_vcp_data,
-                emu_port: UDP_PORT + VCP_PORT_OFFSET,
-            };
-            iface_vcp.add(&mut config).unwrap();
-        }
-
-        usb_open(config).unwrap();
-        usb_close();
-    }
-}
-
-fn set_global_serial_number(sn: &CStr) -> &'static CStr {
-    static mut GLOBAL_BUFFER: [u8; 64] = [0; 64];
-
-    // SAFETY: We are in a single threaded context, so the only possible race on
-    // `GLOBAL_BUFFER` is with the USB stack. We should take care to only call
-    // `set_global_serial_number` with the USB stopped.
-    unsafe {
-        let sn_nul = sn.to_bytes_with_nul();
-
-        // Panics if `sn_nul` is bigger then `GLOBAL_BUFFER`.
-        GLOBAL_BUFFER[..sn_nul.len()].copy_from_slice(sn_nul);
-
-        CStr::from_bytes_with_nul_unchecked(&GLOBAL_BUFFER[..sn_nul.len()])
-    }
-}

core/embed/rust/src/util.rs

@@ -1,14 +1,14 @@
 use core::slice;
 
-use crate::micropython::time;
-use crate::time::Duration;
 use crate::{
     error::Error,
     micropython::{
         map::{Map, MapElem},
         obj::Obj,
         runtime::raise_exception,
+        time,
     },
+    time::Duration,
 };
 
 /// Wait an unspecified short amount of time. To be used in busy loops.