usb-linux: Refuse iso packets when max packet size is 0 (alt setting 0)

Refuse iso usb packets when then max packet size for the endpoint is 0,
this avoids an abort in usb_host_alloc_iso() caused by trying to qemu_malloc
a 0 bytes large buffer.

diff --git a/usb-linux.c b/usb-linux.c
index 6aef7a5db0d12a02f8c0aca259f5501083fbe2a1..4c42fe181aa7cb03c0e18d0bef0006e5152f88d4 100644 (file)
--- a/usb-linux.c
+++ b/usb-linux.c
@@ -549,7 +549,11 @@ static int urb_status_to_usb_ret(int status)
 static int usb_host_handle_iso_data(USBHostDevice *s, USBPacket *p)
 {
     AsyncURB *aurb;
-    int i, j, ret, len = 0;
+    int i, j, ret, max_packet_size, len = 0;
+
+    max_packet_size = get_max_packet_size(s, p->devep);
+    if (max_packet_size == 0)
+        return USB_RET_NAK;
 
     aurb = get_iso_urb(s, p->devep);
     if (!aurb) {