[src/trunk]: src/sys/uvm Change 'npgs' from int to size_t. Otherwise the 64bi...

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

details:   https://anonhg.NetBSD.org/src/rev/337f599ce3b4
branches:  trunk
changeset: 463035:337f599ce3b4
user:      maxv <maxv%NetBSD.org@localhost>
date:      Tue Aug 06 08:10:27 2019 +0000

description:
Change 'npgs' from int to size_t. Otherwise the 64bit->32bit conversion
could lead to npgs=0, which is not expected. It later triggers a panic
in uvm_vsunlock().

Found by TriforceAFL (Akul Pillai).

diffstat:

 sys/uvm/uvm_mmap.c |  7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diffs (28 lines):

diff -r 3171cd7ed2c5 -r 337f599ce3b4 sys/uvm/uvm_mmap.c
--- a/sys/uvm/uvm_mmap.c        Tue Aug 06 05:37:30 2019 +0000
+++ b/sys/uvm/uvm_mmap.c        Tue Aug 06 08:10:27 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_mmap.c,v 1.172 2019/04/06 03:06:29 thorpej Exp $   */
+/*     $NetBSD: uvm_mmap.c,v 1.173 2019/08/06 08:10:27 maxv Exp $      */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -46,7 +46,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_mmap.c,v 1.172 2019/04/06 03:06:29 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_mmap.c,v 1.173 2019/08/06 08:10:27 maxv Exp $");
 
 #include "opt_compat_netbsd.h"
 #include "opt_pax.h"
@@ -132,7 +132,8 @@
        vaddr_t start, end, lim;
        struct vm_map *map;
        vsize_t len;
-       int error = 0, npgs;
+       int error = 0;
+       size_t npgs;
 
        map = &p->p_vmspace->vm_map;