[src/trunk]: src/sys/dev/usb usbdi(9): Make usb_desc_iter_next_interface reje...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/a4bade64b46a
branches:  trunk
changeset: 365284:a4bade64b46a
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Apr 17 13:16:52 2022 +0000

description:
usbdi(9): Make usb_desc_iter_next_interface reject truncated descs.

Currently callers have to check whether the descriptor is truncated,
which is willy.

diffstat:

 sys/dev/usb/usbdi_util.c |  10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diffs (31 lines):

diff -r 7c49c37fa795 -r a4bade64b46a sys/dev/usb/usbdi_util.c
--- a/sys/dev/usb/usbdi_util.c  Sun Apr 17 13:16:43 2022 +0000
+++ b/sys/dev/usb/usbdi_util.c  Sun Apr 17 13:16:52 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: usbdi_util.c,v 1.86 2022/04/17 13:16:43 riastradh Exp $        */
+/*     $NetBSD: usbdi_util.c,v 1.87 2022/04/17 13:16:52 riastradh Exp $        */
 
 /*
  * Copyright (c) 1998, 2012 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: usbdi_util.c,v 1.86 2022/04/17 13:16:43 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: usbdi_util.c,v 1.87 2022/04/17 13:16:52 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -769,7 +769,11 @@
                usb_desc_iter_next(iter);
        }
 
-       return (const usb_interface_descriptor_t *)usb_desc_iter_next(iter);
+       if ((desc = usb_desc_iter_next(iter)) == NULL ||
+           desc->bLength < sizeof(usb_interface_descriptor_t))
+               return NULL;
+       KASSERT(desc->bDescriptorType == UDESC_INTERFACE);
+       return (const usb_interface_descriptor_t *)desc;
 }
 
 /*