From: claudio <claudio@openbsd.org>
Date: Thu, 16 Dec 2021 09:33:56 +0000 (+0000)
Subject: When adding the extra 10% of space to a needed sysctl buffer use math
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=e966ab902416b0cd0b8ed2c3734bf4956e68c211;p=openbsd

When adding the extra 10% of space to a needed sysctl buffer use math
that is less likely to overflow the int type used. A BGP fullfeed is
now so big that this calculation overflowed and then got sign extended.
The result was for example 'route -n show' failures.
Problem identified with deraadt@
OK deraadt@ (more cleanup needed but this fix is a good start)
---

diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index a717d112eb9..b35beb260eb 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtsock.c,v 1.322 2021/09/14 09:15:55 mvs Exp $	*/
+/*	$OpenBSD: rtsock.c,v 1.323 2021/12/16 09:33:56 claudio Exp $	*/
 /*	$NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $	*/
 
 /*
@@ -2219,7 +2219,7 @@ sysctl_rtable(int *name, u_int namelen, void *where, size_t *given, void *new,
 		if (*given < w.w_needed)
 			return (ENOMEM);
 	} else
-		*given = (11 * w.w_needed) / 10;
+		*given = w.w_needed + w.w_needed / 10;
 
 	return (error);
 }