netdev - Re: [v2 PATCH] net: Stop decapitating clones that have a head

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 03 May 2012 06:33:58 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Alexander Duyck <alexander.h.duyck@...el.com>
Cc:	netdev@...r.kernel.org, davem@...emloft.net,
	Eric Dumazet <edumazet@...gle.com>,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: Re: [v2 PATCH] net: Stop decapitating clones that have a head_frag

On Wed, 2012-05-02 at 21:18 -0700, Alexander Duyck wrote:
> This change is meant ot prevent stealing the skb->head to use as a page in
> the event that the skb->head was cloned.  This allows the other clones to
> track each other via shinfo->dataref.
> 
> Without this we break down to two methods for tracking the reference count,
> one being dataref, the other being the page count.  As a result it becomes
> difficult to track how many references there are to skb->head.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
> Cc: Eric Dumazet <edumazet@...gle.com>
> Cc: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
> ---
> 
>  net/core/skbuff.c    |    9 +++++----
>  net/ipv4/tcp_input.c |    9 ++-------
>  2 files changed, 7 insertions(+), 11 deletions(-)
> 
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 52ba2b5..9e8caa0 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -1699,17 +1699,18 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
>  			      struct splice_pipe_desc *spd, struct sock *sk)
>  {
>  	int seg;
> -	bool head_is_linear = !skb->head_frag;
> +	bool head_is_locked = !skb->head_frag || skb_cloned(skb);
>  

Thanks

Acked-by: Eric Dumazet <edumazet@...gle.com>



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html