[src/trunk]: src/sys/external/bsd/drm2/dist/drm/i915 Don't pass null pointer ...

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

details:   https://anonhg.NetBSD.org/src/rev/7af1a9c08505
branches:  trunk
changeset: 455361:7af1a9c08505
user:      msaitoh <msaitoh%NetBSD.org@localhost>
date:      Tue Oct 15 18:50:44 2019 +0000

description:
Don't pass null pointer as argument 2 of memcpy(). Same as Linux.
Found by kUBSan.

diffstat:

 sys/external/bsd/drm2/dist/drm/i915/intel_dp.c |  9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diffs (30 lines):

diff -r b998aaa6eca4 -r 7af1a9c08505 sys/external/bsd/drm2/dist/drm/i915/intel_dp.c
--- a/sys/external/bsd/drm2/dist/drm/i915/intel_dp.c    Tue Oct 15 18:36:38 2019 +0000
+++ b/sys/external/bsd/drm2/dist/drm/i915/intel_dp.c    Tue Oct 15 18:50:44 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: intel_dp.c,v 1.19 2018/09/13 08:25:55 mrg Exp $        */
+/*     $NetBSD: intel_dp.c,v 1.20 2019/10/15 18:50:44 msaitoh Exp $    */
 
 /*
  * Copyright © 2008 Intel Corporation
@@ -28,7 +28,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: intel_dp.c,v 1.19 2018/09/13 08:25:55 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: intel_dp.c,v 1.20 2019/10/15 18:50:44 msaitoh Exp $");
 
 #include <linux/i2c.h>
 #include <linux/slab.h>
@@ -989,7 +989,10 @@
                if (WARN_ON(txsize > 20))
                        return -E2BIG;
 
-               memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);
+               WARN_ON(!msg->buffer != !msg->size);
+
+               if (msg->buffer)
+                       memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);
 
                ret = intel_dp_aux_ch(intel_dp, txbuf, txsize, rxbuf, rxsize);
                if (ret > 0) {