[src/trunk]: src/sys/compat/common - make sure size is not used uninitialized

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

details:   https://anonhg.NetBSD.org/src/rev/4250a0f55252
branches:  trunk
changeset: 744356:4250a0f55252
user:      christos <christos%NetBSD.org@localhost>
date:      Thu Jan 30 14:07:40 2020 +0000

description:
- make sure size is not used uninitialized
- limit size range
- fix type botch for "size"
from maxv@

diffstat:

 sys/compat/common/kern_info_43.c |  18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diffs (41 lines):

diff -r dc30942ea7db -r 4250a0f55252 sys/compat/common/kern_info_43.c
--- a/sys/compat/common/kern_info_43.c  Thu Jan 30 13:56:48 2020 +0000
+++ b/sys/compat/common/kern_info_43.c  Thu Jan 30 14:07:40 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_info_43.c,v 1.38 2020/01/02 15:42:26 thorpej Exp $        */
+/*     $NetBSD: kern_info_43.c,v 1.39 2020/01/30 14:07:40 christos Exp $       */
 
 /*
  * Copyright (c) 1982, 1986, 1991, 1993
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_info_43.c,v 1.38 2020/01/02 15:42:26 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_info_43.c,v 1.39 2020/01/30 14:07:40 christos Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_compat_netbsd.h"
@@ -172,11 +172,19 @@
                syscallarg(int) arg;
        } */
        int error, name[6];
+       int isize;
        size_t size;
 
-       if (SCARG(uap, size) && (error = copyin((void *)SCARG(uap, size),
-           (void *)&size, sizeof(size))))
-               return (error);
+       if (!SCARG(uap, size))
+               return EINVAL;
+
+       if ((error = copyin(SCARG(uap, size), &isize, sizeof(isize))) != 0)
+               return error;
+
+       if (isize < 0 || isize > 4096)
+               return EINVAL;
+
+       size = isize;
 
        switch (SCARG(uap, op) & 0xff00) {