[src/trunk]: src/sys/kern Add a check before the memcpy. memcpy is defined to...

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

details:   https://anonhg.NetBSD.org/src/rev/bf89d9cad2f8
branches:  trunk
changeset: 1004146:bf89d9cad2f8
user:      maxv <maxv%NetBSD.org@localhost>
date:      Mon Oct 14 16:27:03 2019 +0000

description:
Add a check before the memcpy. memcpy is defined to never take NULL as
second argument, and the compiler is free to perform optimizations knowing
that this argument is never NULL.

In this particular case, it was harmless. But still good to fix.

Reported-by: syzbot+6f504255accb795eb6b7%syzkaller.appspotmail.com@localhost

diffstat:

 sys/kern/uipc_socket.c |  8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diffs (29 lines):

diff -r 0b9b3558ee0d -r bf89d9cad2f8 sys/kern/uipc_socket.c
--- a/sys/kern/uipc_socket.c    Mon Oct 14 14:48:48 2019 +0000
+++ b/sys/kern/uipc_socket.c    Mon Oct 14 16:27:03 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uipc_socket.c,v 1.284 2019/09/27 00:32:03 pgoyette Exp $       */
+/*     $NetBSD: uipc_socket.c,v 1.285 2019/10/14 16:27:03 maxv Exp $   */
 
 /*
  * Copyright (c) 2002, 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -71,7 +71,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_socket.c,v 1.284 2019/09/27 00:32:03 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_socket.c,v 1.285 2019/10/14 16:27:03 maxv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_compat_netbsd.h"
@@ -2096,7 +2096,9 @@
        }
 
        sopt->sopt_retsize = MIN(sopt->sopt_size, len);
-       memcpy(sopt->sopt_data, buf, sopt->sopt_retsize);
+       if (sopt->sopt_retsize > 0) {
+               memcpy(sopt->sopt_data, buf, sopt->sopt_retsize);
+       }
 
        return 0;
 }