linux-kernel - Re: [PATCH 3/3] csky: Support kernel non-aligned access

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:   Tue, 20 Aug 2019 19:17:41 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     guoren@...nel.org
Cc:     arnd@...db.de, linux-kernel@...r.kernel.org,
        linux-arch@...r.kernel.org, linux-csky@...r.kernel.org,
        douzhk@...ionalchip.com, Guo Ren <ren_guo@...ky.com>
Subject: Re: [PATCH 3/3] csky: Support kernel non-aligned access

On Tue, Aug 20, 2019 at 08:34:29PM +0800, guoren@...nel.org wrote:
> From: Guo Ren <ren_guo@...ky.com>
> 
> We prohibit non-aligned access in kernel mode, but some special NIC
> driver needs to support kernel-state unaligned access. For example,
> when the bus does not support unaligned access, IP header parsing
> will cause non-aligned access and driver does not recopy the skb
> buffer to dma for performance reasons.
> 
> Added kernel_enable & user_enable to control unaligned access and
> added kernel_count  & user_count for statistical unaligned access.

If the NIC drivers requires this it is buggy.  Kernel code must
use the get_unaligned* / put_unaligned* helpers for that.