linux-kernel - Re: [PATCH] mm: make __GFP_SKIP_ZERO visible to skip zero operation

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]

Message-ID: <202309011130.7543E1DC9D@keescook>
Date:   Fri, 1 Sep 2023 11:32:37 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Alexander Potapenko <glider@...gle.com>
Cc:     Zhaoyang Huang <huangzhaoyang@...il.com>,
        Matthew Wilcox <willy@...radead.org>,
        "zhaoyang.huang" <zhaoyang.huang@...soc.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, ke.wang@...soc.com,
        Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Michal Hocko <mhocko@...nel.org>,
        Eric Biggers <ebiggers@...nel.org>,
        Mateusz Guzik <mjguzik@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Al Viro <viro@...iv.linux.org.uk>
Subject: Re: [PATCH] mm: make __GFP_SKIP_ZERO visible to skip zero operation

On Fri, Sep 01, 2023 at 02:55:17PM +0200, Alexander Potapenko wrote:
> A draft implementation at
> https://github.com/ramosian-glider/linux/commit/00791be14eb1113eae615c74b652f94b5cc3c336
> (which probably does not apply anymore) may give some insight into how
> this is supposed to work.
> There's plenty of room for bikeshedding here (does the command-line
> flag opt-in or opt-out? should we use function names instead of some
> "keys"? can we allow overriding every allocation site without the need
> for alloc_pages_uninit()?), but if the overall scheme is viable I can
> probably proceed with an RFC.

This is my preferred direction to go with this idea (though I agree some
internals could be partially whitelisted: the "dup" functions need to
wipe the trailing rounded-up bucket size bytes still).

-- 
Kees Cook