From 5e8e36e4e3328c5f5a2753b0fac633b2d0ebd0ff Mon Sep 17 00:00:00 2001
From: alufers <alufers@wp.pl>
Date: Tue, 5 Mar 2024 15:41:32 +0100
Subject: [PATCH] fix: panic when trying to iterate over an interface with zero
 endpoints

Some USB classes (UVC, UAC) provide alternate setting descriptors of interfaces with zero endpoints. Trying to call `endpoint_descriptors` on them caused a panic, because NULL was passed to `slice::from_raw_parts`. A branch was introduced to check for that case and create an iterator over an empty slice.

See: https://stackoverflow.com/a/49244874/2948315
---
 src/interface_descriptor.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/src/interface_descriptor.rs b/src/interface_descriptor.rs
index eb6419f..d4c64c3 100644
--- a/src/interface_descriptor.rs
+++ b/src/interface_descriptor.rs
@@ -101,11 +101,9 @@ impl<'a> InterfaceDescriptor<'a> {
 
     /// Returns an iterator over the interface's endpoint descriptors.
     pub fn endpoint_descriptors(&self) -> EndpointDescriptors<'a> {
-        let endpoints = unsafe {
-            slice::from_raw_parts(
-                self.descriptor.endpoint,
-                self.descriptor.bNumEndpoints as usize,
-            )
+        let endpoints = match self.descriptor.bNumEndpoints {
+            0 => &[],
+            n => unsafe { slice::from_raw_parts(self.descriptor.endpoint, n as usize) },
         };
 
         EndpointDescriptors {