udp_diag: Fix socket skipping within chain

udp_diag: Fix socket skipping within chain

[Herbert Xu]

While working on rhashtable walking I noticed that the UDP diag
dumping code is buggy.  In particular, the socket skipping within
a chain never happens, even though we record the number of sockets
that should be skipped.

As this code was supposedly copied from TCP, this patch does what
TCP does and resets num before we walk a chain.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
index 7927db0..4a000f1 100644
--- a/net/ipv4/udp_diag.c
+++ b/net/ipv4/udp_diag.c
@@ -99,11 +99,13 @@ static void udp_dump(struct udp_table *table, struct sk_buff *skb, struct netlin
 	s_slot = cb->args[0];
 	num = s_num = cb->args[1];
 
-	for (slot = s_slot; slot <= table->mask; num = s_num = 0, slot++) {
+	for (slot = s_slot; slot <= table->mask; s_num = 0, slot++) {
 		struct sock *sk;
 		struct hlist_nulls_node *node;
 		struct udp_hslot *hslot = &table->hash[slot];
 
+		num = 0;
+
 		if (hlist_nulls_empty(&hslot->head))
 			continue;
 
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

Re: udp_diag: Fix socket skipping within chain

[Pavel Emelyanov]

On 01/24/2015 12:02 AM, Herbert Xu wrote:
> While working on rhashtable walking I noticed that the UDP diag
> dumping code is buggy.  In particular, the socket skipping within
> a chain never happens, even though we record the number of sockets
> that should be skipped.
> 
> As this code was supposedly copied from TCP, this patch does what
> TCP does and resets num before we walk a chain.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Acked-by: Pavel Emelyanov <xemul@parallels.com>

Thanks,
Pavel

> diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
> index 7927db0..4a000f1 100644
> --- a/net/ipv4/udp_diag.c
> +++ b/net/ipv4/udp_diag.c
> @@ -99,11 +99,13 @@ static void udp_dump(struct udp_table *table, struct sk_buff *skb, struct netlin
>  	s_slot = cb->args[0];
>  	num = s_num = cb->args[1];
>  
> -	for (slot = s_slot; slot <= table->mask; num = s_num = 0, slot++) {
> +	for (slot = s_slot; slot <= table->mask; s_num = 0, slot++) {
>  		struct sock *sk;
>  		struct hlist_nulls_node *node;
>  		struct udp_hslot *hslot = &table->hash[slot];
>  
> +		num = 0;
> +
>  		if (hlist_nulls_empty(&hslot->head))
>  			continue;
>  
> 

Re: udp_diag: Fix socket skipping within chain

[David Miller]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Sat, 24 Jan 2015 08:02:40 +1100

> While working on rhashtable walking I noticed that the UDP diag
> dumping code is buggy.  In particular, the socket skipping within
> a chain never happens, even though we record the number of sockets
> that should be skipped.
> 
> As this code was supposedly copied from TCP, this patch does what
> TCP does and resets num before we walk a chain.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Applied and queued up for -stable, thanks Herbert.