[src/trunk]: src/sys/rump/librump/rumpvfs Avoid copying zero-sized objects (f...

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

details:   https://anonhg.NetBSD.org/src/rev/e728ff4a6a1d
branches:  trunk
changeset: 1008861:e728ff4a6a1d
user:      kamil <kamil%NetBSD.org@localhost>
date:      Sat Apr 04 19:24:51 2020 +0000

description:
Avoid copying zero-sized objects (from the NULL address)

Detected with UBSan

diffstat:

 sys/rump/librump/rumpvfs/rumpfs.c |  10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diffs (38 lines):

diff -r bfdc2e6f94b5 -r e728ff4a6a1d sys/rump/librump/rumpvfs/rumpfs.c
--- a/sys/rump/librump/rumpvfs/rumpfs.c Sat Apr 04 19:02:53 2020 +0000
+++ b/sys/rump/librump/rumpvfs/rumpfs.c Sat Apr 04 19:24:51 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rumpfs.c,v 1.154 2020/01/17 20:08:09 ad Exp $  */
+/*     $NetBSD: rumpfs.c,v 1.155 2020/04/04 19:24:51 kamil Exp $       */
 
 /*
  * Copyright (c) 2009, 2010, 2011 Antti Kantee.  All Rights Reserved.
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rumpfs.c,v 1.154 2020/01/17 20:08:09 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rumpfs.c,v 1.155 2020/04/04 19:24:51 kamil Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -977,7 +977,8 @@
                        return ENOSPC;
 
                copylen = MIN(rn->rn_dlen, newlen);
-               memcpy(newdata, rn->rn_data, copylen);
+               if (copylen > 0)
+                       memcpy(newdata, rn->rn_data, copylen);
                memset((char *)newdata + copylen, 0, newlen - copylen);
 
                if ((rn->rn_flags & RUMPNODE_EXTSTORAGE) == 0) {
@@ -1492,7 +1493,8 @@
                        return ENOSPC;
                rn->rn_dlen = newlen;
                memset(rn->rn_data, 0, newlen);
-               memcpy(rn->rn_data, olddata, oldlen);
+               if (oldlen > 0)
+                       memcpy(rn->rn_data, olddata, oldlen);
                allocd = true;
                uvm_vnp_setsize(vp, newlen);
        }