ioctl: Allow ZLP control writes

Closes #21 Signed-off-by: Tormod Volden <[email protected]> [Peter: only consider zlp if transfer_buffer_length is zero] Signed-off-by: Peter Dons Tychsen <[email protected]>
mcuee · Oct 17, 2021 · 52521d0 · 52521d0
1 parent ee27cd5
commit 52521d0
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/libusb/src/driver/ioctl.c b/libusb/src/driver/ioctl.c
@@ -669,7 +669,8 @@ NULL : input_buffer + sizeof(libusb_request),
 		dispCtlCode = "CONTROL_WRITE";
 
 		// check if the request and buffer is valid
-		if (!request || !transfer_buffer_mdl || input_buffer_length < sizeof(libusb_request))
+		// allow for zero length control packets
+		if (!request || (!transfer_buffer_mdl && transfer_buffer_length) || input_buffer_length < sizeof(libusb_request))
 		{
 			USBERR("%s: invalid transfer request\n", dispCtlCode);
 			status = STATUS_INVALID_PARAMETER;