Merge pull request #57 from kevinmehall/windows-interfaces

windows: Allow claiming interfaces that require WinUsb_GetAssociatedInterface

Cargo.toml

@@ -30,3 +30,6 @@ windows-sys = { version = "0.48.0", features = ["Win32_Devices_Usb", "Win32_Devi
 core-foundation = "0.9.3"
 core-foundation-sys = "0.8.4"
 io-kit-sys = "0.4.0"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(fuzzing)'] }

src/descriptors.rs

@@ -28,6 +28,8 @@ pub(crate) const DESCRIPTOR_LEN_INTERFACE: u8 = 9;
 pub(crate) const DESCRIPTOR_TYPE_ENDPOINT: u8 = 0x05;
 pub(crate) const DESCRIPTOR_LEN_ENDPOINT: u8 = 7;
 
+pub(crate) const DESCRIPTOR_TYPE_STRING: u8 = 0x03;
+
 /// USB defined language IDs for string descriptors.
 ///
 /// In practice, different language IDs are not used,
@@ -352,6 +354,13 @@ impl<'a> InterfaceGroup<'a> {
     pub fn alt_settings(&self) -> impl Iterator<Item = InterfaceAltSetting> {
         self.interfaces.iter().cloned()
     }
+
+    /// Get the descriptor for the first alt setting.
+    ///
+    /// There is guaranteed to be at least one alt setting or this would not have been found.
+    pub fn first_alt_setting(&self) -> InterfaceAltSetting<'a> {
+        self.interfaces[0].clone()
+    }
 }
 
 /// Information about a USB interface alternate setting, with access to associated endpoints and other descriptors.
@@ -549,6 +558,24 @@ pub(crate) fn parse_concatenated_config_descriptors(mut buf: &[u8]) -> impl Iter
     })
 }
 
+pub(crate) fn validate_string_descriptor(data: &[u8]) -> bool {
+    data.len() >= 2 && data[0] as usize == data.len() && data[1] == DESCRIPTOR_TYPE_STRING
+}
+
+pub(crate) fn decode_string_descriptor(data: &[u8]) -> Result<String, ()> {
+    if !validate_string_descriptor(data) {
+        return Err(());
+    }
+
+    Ok(char::decode_utf16(
+        data[2..]
+            .chunks_exact(2)
+            .map(|c| u16::from_le_bytes(c.try_into().unwrap())),
+    )
+    .map(|r| r.unwrap_or(char::REPLACEMENT_CHARACTER))
+    .collect::<String>())
+}
+
 /// Make public when fuzzing
 #[cfg(fuzzing)]
 pub fn fuzz_parse_concatenated_config_descriptors(buf: &[u8]) -> impl Iterator<Item = &[u8]> {

src/device.rs

@@ -3,7 +3,10 @@ use std::{io::ErrorKind, sync::Arc, time::Duration};
 use log::error;
 
 use crate::{
-    descriptors::{ActiveConfigurationError, Configuration, InterfaceAltSetting},
+    descriptors::{
+        decode_string_descriptor, validate_string_descriptor, ActiveConfigurationError,
+        Configuration, InterfaceAltSetting, DESCRIPTOR_TYPE_STRING,
+    },
     platform,
     transfer::{
         Control, ControlIn, ControlOut, EndpointType, Queue, RequestBuffer, TransferError,
@@ -12,9 +15,6 @@ use crate::{
     DeviceInfo, Error,
 };
 
-const STANDARD_REQUEST_GET_DESCRIPTOR: u8 = 0x06;
-const DESCRIPTOR_TYPE_STRING: u8 = 0x03;
-
 /// An opened USB device.
 ///
 /// Obtain a `Device` by calling [`DeviceInfo::open`]:
@@ -123,6 +123,7 @@ impl Device {
 
         #[cfg(not(target_os = "windows"))]
         {
+            const STANDARD_REQUEST_GET_DESCRIPTOR: u8 = 0x06;
             use crate::transfer::{ControlType, Recipient};
 
             let mut buf = vec![0; 4096];
@@ -153,7 +154,14 @@ impl Device {
         timeout: Duration,
     ) -> Result<impl Iterator<Item = u16>, Error> {
         let data = self.get_descriptor(DESCRIPTOR_TYPE_STRING, 0, 0, timeout)?;
-        validate_string_descriptor(&data)?;
+
+        if !validate_string_descriptor(&data) {
+            error!("String descriptor language list read {data:?}, not a valid string descriptor");
+            return Err(Error::new(
+                ErrorKind::InvalidData,
+                "string descriptor data was invalid",
+            ));
+        }
 
         //TODO: Use array_chunks once stable
         let mut iter = data.into_iter().skip(2);
@@ -184,15 +192,9 @@ impl Device {
             ));
         }
         let data = self.get_descriptor(DESCRIPTOR_TYPE_STRING, desc_index, language_id, timeout)?;
-        validate_string_descriptor(&data)?;
-
-        Ok(char::decode_utf16(
-            data[2..]
-                .chunks_exact(2)
-                .map(|c| u16::from_le_bytes(c.try_into().unwrap())),
-        )
-        .map(|r| r.unwrap_or(char::REPLACEMENT_CHARACTER))
-        .collect::<String>())
+
+        decode_string_descriptor(&data)
+            .map_err(|_| Error::new(ErrorKind::InvalidData, "string descriptor data was invalid"))
     }
 
     /// Reset the device, forcing it to re-enumerate.
@@ -309,17 +311,6 @@ impl Device {
     }
 }
 
-fn validate_string_descriptor(data: &[u8]) -> Result<(), Error> {
-    if data.len() < 2 || data[0] as usize != data.len() || data[1] != DESCRIPTOR_TYPE_STRING {
-        error!("String descriptor language list read {data:?}, not a valid string descriptor");
-        return Err(Error::new(
-            ErrorKind::InvalidData,
-            "string descriptor data was invalid",
-        ));
-    }
-    Ok(())
-}
-
 /// An opened interface of a USB device.
 ///
 /// Obtain an `Interface` with the [`Device::claim_interface`] method.