WIP - get_device_id and random bytes in rust

core/embed/rust/librust_qstr.h

@@ -29,6 +29,7 @@ static void _librust_qstrs(void) {
   MP_QSTR_set_rotation;
   MP_QSTR_get_label;
   MP_QSTR_set_label;
+  MP_QSTR_get_device_id;
   MP_QSTR_get_mnemonic_secret;
   MP_QSTR_set_mnemonic_secret;
   MP_QSTR_is_passphrase_enabled;

core/embed/rust/src/storagedevice/storage_device.rs

@@ -7,12 +7,12 @@ use crate::{
         obj::Obj,
         qstr::Qstr,
     },
-    trezorhal::secbool,
+    trezorhal::{random, secbool},
     util,
 };
 
 use cstr_core::cstr;
-use heapless::Vec;
+use heapless::{String, Vec};
 
 use core::{
     convert::{TryFrom, TryInto},
@@ -196,6 +196,26 @@ extern "C" fn storagedevice_set_label(label: Obj) -> Obj {
     unsafe { util::try_or_raise(block) }
 }
 
+extern "C" fn storagedevice_get_device_id() -> Obj {
+    let block = || {
+        let key = _get_appkey(DEVICE_ID, true);
+        let device_id = &storagedevice_storage_get(key) as &[u8];
+
+        // TODO: is there some easier way?
+        // TODO: replace unwrap() with "?"
+        if device_id.is_empty() {
+            let new_device_id = &random::get_random_bytes(12) as &[u8];
+            let hex_id = _hexlify_bytes(new_device_id);
+            let device_id_bytes = hex_id.as_str().as_bytes();
+            storagedevice_storage_set(key, device_id_bytes.as_ptr(), device_id_bytes.len() as u16);
+            hex_id.as_str().try_into()
+        } else {
+            str::from_utf8(device_id).unwrap().try_into()
+        }
+    };
+    unsafe { util::try_or_raise(block) }
+}
+
 extern "C" fn storagedevice_get_mnemonic_secret() -> Obj {
     let block = || {
         let key = _get_appkey(_MNEMONIC_SECRET, false);
@@ -548,13 +568,7 @@ pub fn storagedevice_storage_get(key: u16) -> Vec<u8, MAX_LEN> {
     // Would mean having Option<XXX> as the return type
 
     let result = &buf[..len as usize];
-    // TODO: can we somehow convert it more easily?
+    result.iter().cloned().collect()
-    let mut vector_result = Vec::<u8, MAX_LEN>::new();
-    for byte in result {
-        vector_result.push(*byte).unwrap();
-    }
-
-    vector_result
 }
 
 // TODO: is it worth having a special function to not allocate so much in all
@@ -693,6 +707,23 @@ fn _normalize_autolock_delay(delay_ms: u32) -> u32 {
     }
 }
 
+// TODO: could be put elsewhere to be available for all modules
+pub fn _hexlify_bytes(bytes: &[u8]) -> String<64> {
+    let mut buf = String::<64>::from("");
+    for byte in bytes {
+        fn hex_from_digit(num: u8) -> char {
+            if num < 10 {
+                (b'0' + num) as char
+            } else {
+                (b'A' + num - 10) as char
+            }
+        }
+        buf.push(hex_from_digit(byte / 16)).unwrap();
+        buf.push(hex_from_digit(byte % 16)).unwrap();
+    }
+    buf
+}
+
 #[no_mangle]
 pub static mp_module_trezorstoragedevice: Module = obj_module! {
     Qstr::MP_QSTR___name_storage__ => Qstr::MP_QSTR_trezorstoragedevice.to_obj(),
@@ -734,6 +765,10 @@ pub static mp_module_trezorstoragedevice: Module = obj_module! {
     ///     """Set label."""
     Qstr::MP_QSTR_set_label => obj_fn_1!(storagedevice_set_label).as_obj(),
 
+    /// def get_device_id() -> str:
+    ///     """Get device ID."""
+    Qstr::MP_QSTR_get_device_id => obj_fn_0!(storagedevice_get_device_id).as_obj(),
+
     /// def get_mnemonic_secret() -> bytes:
     ///     """Get mnemonic secret."""
     Qstr::MP_QSTR_get_mnemonic_secret => obj_fn_0!(storagedevice_get_mnemonic_secret).as_obj(),
@@ -917,4 +952,11 @@ mod tests {
         let result = _normalize_autolock_delay(1_000_000);
         assert_eq!(result, 1_000_000);
     }
+
+    #[test]
+    fn hexlify_bytes() {
+        let bytes: &[u8; 6] = &[52, 241, 6, 151, 173, 74];
+        let result = _hexlify_bytes(bytes);
+        assert_eq!(result, String::<64>::from("34F10697AD4A"));
+    }
 }

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

@@ -1,8 +1,14 @@
+use heapless::Vec;
+
 extern "C" {
     // trezor-crypto/rand.h
     fn random_uniform(n: u32) -> u32;
+    fn random_buffer(buf: *const u8, len: u16);
 }
 
+// TODO: what is the sensible max size not to allocate too much every time?
+const MAX_LEN: usize = u8::MAX as usize;
+
 pub fn uniform(n: u32) -> u32 {
     unsafe { random_uniform(n) }
 }
@@ -15,6 +21,10 @@ pub fn shuffle<T>(slice: &mut [T]) {
     }
 }
 
-// TODO: create random_bytes()
+pub fn get_random_bytes(len: u8) -> Vec<u8, MAX_LEN> {
-// from trezorcrypto import random
+    let mut buf: [u8; MAX_LEN] = [0; MAX_LEN];
-// random_buffer
+    unsafe { random_buffer(&mut buf as *mut _, len as u16) };
+
+    let result = &buf[..len as usize];
+    result.iter().cloned().collect()
+}

core/mocks/generated/trezorstoragedevice.pyi

@@ -43,6 +43,11 @@ def set_label(label: str) -> bool:
     """Set label."""
 
 
+# rust/src/storagedevice/storage_device.rs
+def get_device_id() -> str:
+    """Get device ID."""
+
+
 # rust/src/storagedevice/storage_device.rs
 def get_mnemonic_secret() -> bytes:
     """Get mnemonic secret."""

core/src/apps/base.py

@@ -42,7 +42,7 @@ def get_features() -> Features:
         patch_version=utils.VERSION_PATCH,
         revision=utils.SCM_REVISION,
         model=utils.MODEL,
-        device_id=storage.device.get_device_id(),
+        device_id=storagedevice.get_device_id(),
         label=storagedevice.get_label(),
         pin_protection=config.has_pin(),
         unlocked=config.is_unlocked(),

core/src/main.py

@@ -45,9 +45,9 @@ with unimport_manager:
     del boot
 
 # start the USB
-import storage.device
+from trezor import storagedevice
 
-usb.bus.open(storage.device.get_device_id())
+usb.bus.open(storagedevice.get_device_id())
 
 # run the endless loop
 while True:

core/src/storage/__init__.py

@@ -27,7 +27,7 @@ def reset() -> None:
     """
     Wipes storage but keeps the device id unchanged.
     """
-    device_id = device.get_device_id()
+    device_id = storagedevice.get_device_id()
     wipe()
     common.set(common.APP_DEVICE, device.DEVICE_ID, device_id.encode(), public=True)
 

core/src/storage/device.py

@@ -1,10 +1,12 @@
 from micropython import const
 from typing import TYPE_CHECKING
-from ubinascii import hexlify
 
 import storage.cache
 from storage import common
 
+# from ubinascii import hexlify
+
+
 # TODO: try ... from trezorstoragedevice import *
 
 
@@ -82,18 +84,18 @@ SD_SALT_AUTH_KEY_LEN_BYTES = const(16)
 #     return common.get_bool(_NAMESPACE, INITIALIZED, public=True)
 
 
-def _new_device_id() -> str:
+# def _new_device_id() -> str:
-    from trezorcrypto import random  # avoid pulling in trezor.crypto
+#     from trezorcrypto import random  # avoid pulling in trezor.crypto
 
-    return hexlify(random.bytes(12)).decode().upper()
+#     return hexlify(random.bytes(12)).decode().upper()
 
 
-def get_device_id() -> str:
+# def get_device_id() -> str:
-    dev_id = common.get(_NAMESPACE, DEVICE_ID, public=True)
+#     dev_id = common.get(_NAMESPACE, DEVICE_ID, public=True)
-    if not dev_id:
+#     if not dev_id:
-        dev_id = _new_device_id().encode()
+#         dev_id = _new_device_id().encode()
-        common.set(_NAMESPACE, DEVICE_ID, dev_id, public=True)
+#         common.set(_NAMESPACE, DEVICE_ID, dev_id, public=True)
-    return dev_id.decode()
+#     return dev_id.decode()
 
 
 # def get_rotation() -> int:

core/src/storage/sd_salt.py

@@ -1,7 +1,6 @@
 from micropython import const
 from typing import TYPE_CHECKING
 
-import storage.device
 from trezor import io, storagedevice
 from trezor.sdcard import with_filesystem
 from trezor.utils import consteq
@@ -32,7 +31,7 @@ def compute_auth_tag(salt: bytes, auth_key: bytes) -> bytes:
 
 
 def _get_device_dir() -> str:
-    return f"/trezor/device_{storage.device.get_device_id().lower()}"
+    return f"/trezor/device_{storagedevice.get_device_id().lower()}"
 
 
 def _get_salt_path(new: bool = False) -> str: