Date: Thu, 3 Jan 2013 17:45:11 -0800 (PST) From: Keith Sklower <sklower@cs.berkeley.edu> To: FreeBSD-gnats-submit@FreeBSD.org Cc: deter-ops@isi.edu Subject: kern/174959: [patch] rnh_walktree_from visits spurious nodes Message-ID: <201301040145.r041jBwb003568@users.isi.deterlab.net> Resent-Message-ID: <201301040210.r042A0g8091541@freefall.freebsd.org>
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>Number: 174959
>Category: kern
>Synopsis: [patch] rnh_walktree_from visits spurious nodes
>Confidential: no
>Severity: serious
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jan 04 02:10:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator: Keith Sklower
>Release: FreeBSD 9.1-RC2 i386
>Organization:
University of California, Berkeley
>Environment:
System: FreeBSD users.isi.deterlab.net 9.1-RC2 FreeBSD 9.1-RC2 #7: Tue Oct 9 19:14:50 PDT 2012 root@users.isi.deterlab.net:/usr/obj/usr/src/sys/USERS9 i386
any machine, any version of FreeBSD after 2.3
>Description:
The radix tree method rnh_walktree_from (as implemented
by rn_walktree_from in /sys/net/radix.c) invokes the helper
function f on nodes that it should not, even when supplied with
inputs adhering to its unreasonably strict assumptions.
It is low priority because nothing in the source
distribution uses this function anymore. We have a local need for it.
>How-To-Repeat:
Construct a routing tree with the following 4 routes:
128.32.8.0/24
128.32.9.0/24
128.32.8.1 (host)
128.32.8.2 (host)
invoke rn_walktree_from(tree, 128.32.9.0, 255.255.255.0, f, 0)
where f prints the IP address in each leaf visited.
[I can supply 94 line C program that demonstrates this at user level]
It should only visit 128.32.9.0/24; instead it visits the entire
tree.
>Fix:
--- radix.c 2012-11-28 10:23:37.000000000 -0800
+++ radix.c.pfix 2013-01-03 16:12:33.000000000 -0800
@@ -1009,11 +1009,11 @@
/*
* Two cases: either we stepped off the end of our mask,
* in which case last == rn, or we reached a leaf, in which
- * case we want to start from the last node we looked at.
- * Either way, last is the node we want to start from.
+ * case we want to start from the leaf.
*/
- rn = last;
- lastb = rn->rn_bit;
+ if (rn-> rn_bit >= 0)
+ rn = last;
+ lastb = last->rn_bit;
/* printf("rn %p, lastb %d\n", rn, lastb);*/
>Release-Note:
>Audit-Trail:
>Unformatted:
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