trezor.config: add public values (readable without unlock)

They are indicated via MSB bit of appid

embed/extmod/modtrezorconfig/modtrezorconfig.c

@@ -65,14 +65,17 @@ STATIC mp_obj_t mod_trezorconfig_change_pin(mp_obj_t pin, mp_obj_t newpin, mp_ob
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorconfig_change_pin_obj, mod_trezorconfig_change_pin);
 
-/// def get(app: int, key: int) -> bytes:
+/// def get(app: int, key: int, public: bool=False) -> bytes:
 ///     '''
 ///     Gets a value of given key for given app (or empty bytes if not set).
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_get(mp_obj_t app, mp_obj_t key) {
+STATIC mp_obj_t mod_trezorconfig_get(size_t n_args, const mp_obj_t *args) {
-    uint8_t a = mp_obj_get_int(app);
+    uint8_t app = mp_obj_get_int(args[0]) & 0x7F;
-    uint8_t k = mp_obj_get_int(key);
+    uint8_t key = mp_obj_get_int(args[1]);
-    uint16_t appkey = a << 8 | k;
+    if (n_args > 2 && args[2] == mp_const_true) {
+        app |= 0x80;
+    }
+    uint16_t appkey = (app << 8) | key;
     uint16_t len = 0;
     const void *val;
     if (sectrue != storage_get(appkey, &val, &len) || len == 0) {
@@ -80,24 +83,27 @@ STATIC mp_obj_t mod_trezorconfig_get(mp_obj_t app, mp_obj_t key) {
     }
     return mp_obj_new_bytes(val, len);
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_trezorconfig_get_obj, mod_trezorconfig_get);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_get_obj, 2, 3, mod_trezorconfig_get);
 
-/// def set(app: int, key: int, value: bytes) -> None:
+/// def set(app: int, key: int, value: bytes, public: bool=False) -> None:
 ///     '''
 ///     Sets a value of given key for given app.
 ///     '''
-STATIC mp_obj_t mod_trezorconfig_set(mp_obj_t app, mp_obj_t key, mp_obj_t value) {
+STATIC mp_obj_t mod_trezorconfig_set(size_t n_args, const mp_obj_t *args) {
-    uint8_t a = mp_obj_get_int(app);
+    uint8_t app = mp_obj_get_int(args[0]) & 0x7F;
-    uint8_t k = mp_obj_get_int(key);
+    uint8_t key = mp_obj_get_int(args[1]);
-    uint16_t appkey = a << 8 | k;
+    if (n_args > 3 && args[3] == mp_const_true) {
-    mp_buffer_info_t v;
+        app |= 0x80;
-    mp_get_buffer_raise(value, &v, MP_BUFFER_READ);
+    }
-    if (sectrue != storage_set(appkey, v.buf, v.len)) {
+    uint16_t appkey = (app << 8) | key;
+    mp_buffer_info_t value;
+    mp_get_buffer_raise(args[2], &value, MP_BUFFER_READ);
+    if (sectrue != storage_set(appkey, value.buf, value.len)) {
         mp_raise_msg(&mp_type_RuntimeError, "Could not save value");
     }
     return mp_const_none;
 }
-STATIC MP_DEFINE_CONST_FUN_OBJ_3(mod_trezorconfig_set_obj, mod_trezorconfig_set);
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mod_trezorconfig_set_obj, 3, 4, mod_trezorconfig_set);
 
 /// def wipe() -> None:
 ///     '''

embed/extmod/modtrezorconfig/storage.c

@@ -169,7 +169,13 @@ secbool storage_unlock(const uint32_t pin, mp_obj_t callback)
 
 secbool storage_get(uint16_t key, const void **val, uint16_t *len)
 {
-    if (sectrue != initialized || sectrue != unlocked || (key >> 8) == 0) {
+    const uint8_t app = key >> 8;
+    // APP == 0 is reserved for PIN related values
+    if (sectrue != initialized || app == 0) {
+        return secfalse;
+    }
+    // top bit of APP set indicates the value can be read from unlocked device
+    if (sectrue != unlocked && ((app & 0x80) == 0)) {
         return secfalse;
     }
     return norcow_get(key, val, len);
@@ -177,7 +183,9 @@ secbool storage_get(uint16_t key, const void **val, uint16_t *len)
 
 secbool storage_set(uint16_t key, const void *val, uint16_t len)
 {
-    if (sectrue != initialized || sectrue != unlocked || (key >> 8) == 0) {
+    const uint8_t app = key >> 8;
+    // APP == 0 is reserved for PIN related values
+    if (sectrue != initialized || sectrue != unlocked || app == 0) {
         return secfalse;
     }
     return norcow_set(key, val, len);

tests/test_trezor.config.py

@@ -11,7 +11,7 @@ PINKEY = 0x00
 
 def random_entry():
     while True:
-        appid, key = 1 + random.uniform(255), random.uniform(256)
+        appid, key = 1 + random.uniform(127), random.uniform(256)
         if appid != PINAPP or key != PINKEY:
             break
     return appid, key
@@ -56,6 +56,33 @@ class TestConfig(unittest.TestCase):
         config.wipe()
         self.assertEqual(config.change_pin(pin_to_int(''), pin_to_int('000'), None), False)
 
+    def test_public(self):
+        config.init()
+        config.wipe()
+        self.assertEqual(config.unlock(pin_to_int(''), None), True)
+
+        appid, key = random_entry()
+
+        value32 = random.bytes(32)
+        config.set(appid, key, value32)
+        value16 = random.bytes(16)
+        config.set(appid, key, value16, True)
+
+        v1 = config.get(appid, key)
+        v2 = config.get(appid, key, True)
+        self.assertNotEqual(v1, v2)
+        self.assertEqual(v1, value32)
+        self.assertEqual(v2, value16)
+
+        config.init()
+
+        v1 = config.get(appid, key)
+        v2 = config.get(appid, key, True)
+        self.assertNotEqual(v1, v2)
+        self.assertEqual(v1, bytes())
+        self.assertEqual(v2, value16)
+
+
     def test_change_pin(self):
         config.init()
         config.wipe()