netdev - Re: A couple of questions about the SKB fragments

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] [day] [month] [year] [list]

Date:	Sat, 7 May 2016 12:21:01 +0300
From:	Ilya Matveychikov <matvejchikov@...il.com>
To:	Edward Cree <ecree@...arflare.com>
Cc:	netdev@...r.kernel.org, Aleksey.Baulin@...il.com
Subject: Re: A couple of questions about the SKB fragments

2016-05-05 14:13 GMT+03:00 Edward Cree <ecree@...arflare.com>:
> On 05/05/16 08:40, Ilya Matveychikov wrote:
> > Is there any docs except the kernel sources itself to refer to?

> davem has some docs up at http://vger.kernel.org/~davem/skb.html and
> http://vger.kernel.org/~davem/skb_data.html
> In particular note the following:
> "The frag_list is used to maintain a chain of SKBs organized for
>  fragmentation purposes, it is _not_ used for maintaining paged data."
> So my reading would suggest there is no way to multiple-layer-fragment
> an SKB; the frags are page pointers and offsets, not entire sk_buff
> structs in their own right.
>

Seems that the docs is slightly outdated. I think the structure of SKB does
not impose any restrictions on the nesting of the fragments. But is there
any of them in the kernel's code?