[src/trunk]: src/tests/modules Avoid undefined behavior in get_modstat_info

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

details:   https://anonhg.NetBSD.org/src/rev/6fa93b85c6b0
branches:  trunk
changeset: 745036:6fa93b85c6b0
user:      kamil <kamil%NetBSD.org@localhost>
date:      Sat Feb 22 00:24:15 2020 +0000

description:
Avoid undefined behavior in get_modstat_info

t_modctl.c:114:16, member access within misaligned address 0x71bf5bcede84
for type 'struct modstat_t'

t_modctl.c:116:13, load of misaligned address 0x7e81bc3c9104 for type
'struct modstat_t' which requires 8 byte alignment

diffstat:

 tests/modules/t_modctl.c |  10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diffs (39 lines):

diff -r b05543dec4ad -r 6fa93b85c6b0 tests/modules/t_modctl.c
--- a/tests/modules/t_modctl.c  Sat Feb 22 00:18:55 2020 +0000
+++ b/tests/modules/t_modctl.c  Sat Feb 22 00:24:15 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: t_modctl.c,v 1.14 2019/04/21 11:45:09 maya Exp $       */
+/*     $NetBSD: t_modctl.c,v 1.15 2020/02/22 00:24:15 kamil Exp $      */
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
  * All rights reserved.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: t_modctl.c,v 1.14 2019/04/21 11:45:09 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: t_modctl.c,v 1.15 2020/02/22 00:24:15 kamil Exp $");
 
 #include <sys/module.h>
 #include <sys/sysctl.h>
@@ -87,6 +87,7 @@
        int count;
        struct iovec iov;
        modstat_t *ms;
+       modstat_t m;
 
        check_permission();
        for (len = 8192; ;) {
@@ -111,9 +112,10 @@
        count = *(int *)iov.iov_base;
        ms = (modstat_t *)((char *)iov.iov_base + sizeof(int));
        while ( count ) {
-               if (strcmp(ms->ms_name, name) == 0) {
+               memcpy(&m, ms, sizeof(m));
+               if (strcmp(m.ms_name, name) == 0) {
                        if (msdest != NULL)
-                               *msdest = *ms;
+                               memcpy(msdest, &m, sizeof(*msdest));
                        found = true;
                        break;
                }