[PATCH] ipv6: fix flowlabel seqfile handling

[PATCH] ipv6: fix flowlabel seqfile handling

[James Morris]

There's a bug in the seqfile show operation for flowlabel objects, where 
each hash chain is traversed cumulatively for each element.  The following 
function is called for each element of each chain:

static void ip6fl_fl_seq_show(struct seq_file *seq, struct ip6_flowlabel *fl)
{
        while(fl) {
                seq_printf...
		
		fl = fl->next;
	}
}

Thus, objects can appear mutliple times when reading 
/proc/net/ip6_flowlabel, as the above is called for each element in the 
chain.

The solution is to remove the while() loop from the above, and traverse 
each chain exactly once, per the patch below.  This also removes the 
ip6fl_fl_seq_show() function, which does nothing else.

Please apply.

Signed-off-by: James Morris <jmorris@namei.org>

---

 net/ipv6/ip6_flowlabel.c |   18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)


diff -purN --minimal -X dontdiff linux-2.6.p/net/ipv6/ip6_flowlabel.c linux-2.6.w/net/ipv6/ip6_flowlabel.c
--- linux-2.6.p/net/ipv6/ip6_flowlabel.c	2006-10-30 23:11:02.000000000 -0500
+++ linux-2.6.w/net/ipv6/ip6_flowlabel.c	2006-10-31 00:18:11.000000000 -0500
@@ -627,9 +627,13 @@ static void ip6fl_seq_stop(struct seq_fi
 	read_unlock_bh(&ip6_fl_lock);
 }
 
-static void ip6fl_fl_seq_show(struct seq_file *seq, struct ip6_flowlabel *fl)
+static int ip6fl_seq_show(struct seq_file *seq, void *v)
 {
-	while(fl) {
+	if (v == SEQ_START_TOKEN)
+		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
+			   "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
+	else {
+		struct ip6_flowlabel *fl = v;
 		seq_printf(seq,
 			   "%05X %-1d %-6d %-6d %-6ld %-8ld " NIP6_SEQFMT " %-4d\n",
 			   (unsigned)ntohl(fl->label),
@@ -640,17 +644,7 @@ static void ip6fl_fl_seq_show(struct seq
 			   (long)(fl->expires - jiffies)/HZ,
 			   NIP6(fl->dst),
 			   fl->opt ? fl->opt->opt_nflen : 0);
-		fl = fl->next;
 	}
-}
-
-static int ip6fl_seq_show(struct seq_file *seq, void *v)
-{
-	if (v == SEQ_START_TOKEN)
-		seq_printf(seq, "%-5s %-1s %-6s %-6s %-6s %-8s %-32s %s\n",
-			   "Label", "S", "Owner", "Users", "Linger", "Expires", "Dst", "Opt");
-	else
-		ip6fl_fl_seq_show(seq, v);
 	return 0;
 }
 

Re: [PATCH] ipv6: fix flowlabel seqfile handling

[David Miller]

From: James Morris <jmorris@namei.org>
Date: Tue, 31 Oct 2006 01:20:21 -0500 (EST)

> There's a bug in the seqfile show operation for flowlabel objects, where 
> each hash chain is traversed cumulatively for each element.  The following 
> function is called for each element of each chain:

Wow, there are tons of bugs in the flowlabel code, at least
judging by the number of them you've found in the past few
days :-)

Applied, thanks a lot for all of these fixes James.

Re: [PATCH] ipv6: fix flowlabel seqfile handling

[James Morris]

On Tue, 31 Oct 2006, David Miller wrote:

> From: James Morris <jmorris@namei.org>
> Date: Tue, 31 Oct 2006 01:20:21 -0500 (EST)
> 
> > There's a bug in the seqfile show operation for flowlabel objects, where 
> > each hash chain is traversed cumulatively for each element.  The following 
> > function is called for each element of each chain:
> 
> Wow, there are tons of bugs in the flowlabel code, at least
> judging by the number of them you've found in the past few
> days :-)

It seems that nobody is using them, otherwise they'd have hit these bugs 
long ago.



- James
-- 
James Morris
<jmorris@namei.org>