[src/trunk]: src/sys/dev/rasops Avoid undefined behavior when converting unal...

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

details:   https://anonhg.NetBSD.org/src/rev/ab1556033a1d
branches:  trunk
changeset: 458073:ab1556033a1d
user:      rin <rin%NetBSD.org@localhost>
date:      Mon Jul 29 08:13:50 2019 +0000

description:
Avoid undefined behavior when converting unaligned be32 data to
host integer, found by kUBSan.

Pointed out by msaitoh.

diffstat:

 sys/dev/rasops/rasops.h         |  14 +++++++++++++-
 sys/dev/rasops/rasops1.c        |  10 ++++------
 sys/dev/rasops/rasops_putchar.h |   8 ++++----
 3 files changed, 21 insertions(+), 11 deletions(-)

diffs (95 lines):

diff -r 08960e44478c -r ab1556033a1d sys/dev/rasops/rasops.h
--- a/sys/dev/rasops/rasops.h   Mon Jul 29 08:03:47 2019 +0000
+++ b/sys/dev/rasops/rasops.h   Mon Jul 29 08:13:50 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rasops.h,v 1.37 2019/07/28 12:06:10 rin Exp $ */
+/*     $NetBSD: rasops.h,v 1.38 2019/07/29 08:13:50 rin Exp $ */
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -153,6 +153,18 @@
        ((uint8_t *)(font)->data + ((uc) - ((font)->firstchar)) *       \
            (ri)->ri_fontscale)
 
+static __inline uint32_t
+be32uatoh(uint8_t *p)
+{
+       uint32_t u;
+
+       u  = p[0]; u <<= 8;
+       u |= p[1]; u <<= 8;
+       u |= p[2]; u <<= 8;
+       u |= p[3];
+       return u;
+}
+
 /*
  * rasops_init().
  *
diff -r 08960e44478c -r ab1556033a1d sys/dev/rasops/rasops1.c
--- a/sys/dev/rasops/rasops1.c  Mon Jul 29 08:03:47 2019 +0000
+++ b/sys/dev/rasops/rasops1.c  Mon Jul 29 08:13:50 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rasops1.c,v 1.29 2019/07/29 02:57:41 rin Exp $ */
+/*     $NetBSD: rasops1.c,v 1.30 2019/07/29 08:13:50 rin Exp $ */
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: rasops1.c,v 1.29 2019/07/29 02:57:41 rin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: rasops1.c,v 1.30 2019/07/29 08:13:50 rin Exp $");
 
 #include "opt_rasops.h"
 
@@ -151,8 +151,7 @@
                } else {
                        while (height--) {
                                tmp = *rp & lmask;
-                               fb = fr[3] | (fr[2] << 8) |
-                                   (fr[1] << 16) | (fr[0] << 24);
+                               fb = be32uatoh(fr);
                                fr += fs;
                                if (bg)
                                        fb = ~fb;
@@ -202,8 +201,7 @@
                        while (height--) {
                                tmp0 = rp[0] & lmask;
                                tmp1 = rp[1] & rmask;
-                               fb = fr[3] | (fr[2] << 8) |
-                                   (fr[1] << 16) | (fr[0] << 24);
+                               fb = be32uatoh(fr);
                                fr += fs;
                                if (bg)
                                        fb = ~fb;
diff -r 08960e44478c -r ab1556033a1d sys/dev/rasops/rasops_putchar.h
--- a/sys/dev/rasops/rasops_putchar.h   Mon Jul 29 08:03:47 2019 +0000
+++ b/sys/dev/rasops/rasops_putchar.h   Mon Jul 29 08:13:50 2019 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: rasops_putchar.h,v 1.3 2019/07/28 12:10:52 rin Exp $ */
+/* $NetBSD: rasops_putchar.h,v 1.4 2019/07/29 08:13:50 rin Exp $ */
 
 /* NetBSD: rasops8.c,v 1.41 2019/07/25 03:02:44 rin Exp  */
 /*-
@@ -70,7 +70,8 @@
 {
        struct rasops_info *ri = (struct rasops_info *)cookie;
        struct wsdisplay_font *font = PICK_FONT(ri, uc);
-       int width, height, cnt, fs, fb;
+       int width, height, cnt, fs;
+       uint32_t fb;
        uint8_t *dp, *rp, *hp, *hrp, *fr;
        CLR_TYPE clr[2];
 
@@ -124,8 +125,7 @@
                                hp = hrp;
                                hrp += ri->ri_stride;
                        }
-                       fb = fr[3] | (fr[2] << 8) | (fr[1] << 16) |
-                           (fr[0] << 24);
+                       fb = be32uatoh(fr);
                        fr += fs;
                        for (cnt = width; cnt; cnt--) {
                                SUBST_CLR(dp, (fb >> 31) & 1);