pkg_select: fix buffer overflow

expanding the macro with ++len for size meant our memset to zero was
one bigger than the above allocated size.

while here simplify the problematic macro - malloc+memset zero is calloc.

bump pkgrevision


(maya)

$NetBSD: patch-file.c,v 1.1 2017/12/29 17:55:13 maya Exp $

Avoid buffer overflow from magical side effecting macro expansion

--- file.c.orig	2009-03-08 14:25:53.000000000 +0000
+++ file.c
@@ -156,7 +156,9 @@ loadfile(const char *path)
 	if (len == 0)
 		return(NULL);
 
-	XMALLOC(lfile, ++len * sizeof(char *));
+	++len;
+
+	XMALLOC(lfile, len * sizeof(char *));
 
 	for (i = 0; i < len; i++)
 		lfile[i] = NULL;

$NetBSD: patch-tools.h,v 1.1 2017/12/29 17:55:13 maya Exp $

malloc+memset to calloc

--- tools.h.orig	2009-03-08 14:25:53.000000000 +0000
+++ tools.h
@@ -74,10 +74,9 @@
 
 #define XMALLOC(elm, size)						\
 	do {								\
-		elm = malloc(size);					\
+		elm = calloc(1, size);					\
 		if (elm == NULL)					\
 			err(1, "can't allocate memory\n");		\
-		memset(elm, 0, size);					\
 	} while (/* CONSTCOND */ 0)
 
 #define XSTRDUP(dest, src)						\