linux-kernel - Re: [GIT PULL] overlayfs fixes for 5.14-rc6

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:   Mon, 9 Aug 2021 14:25:17 -0700
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Miklos Szeredi <miklos@...redi.hu>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        linux-unionfs@...r.kernel.org
Subject: Re: [GIT PULL] overlayfs fixes for 5.14-rc6

On Mon, Aug 9, 2021 at 10:00 AM Miklos Szeredi <miklos@...redi.hu> wrote:
>
>       ovl: fix mmap denywrite

Ugh. Th edances with denywrite and mapping_unmap_writable are really
really annoying.

I've pulled this, but I really get the feeling that there's duplicated
code for these things, and that all the "if error goto" cases  (some
old, some new) are really really uglky.

I get the feeling that the whole thing with deny_write_access and
mapping_map_writable could possibly be done after-the-fact somehow as
part of actually inserting the vma in the vma tree, rather than done
as the vma is prepared.

And most users of vma_set_file() probably really don't want that whole
thing at all (ie the DRM stuff that just switches out a local thing.
They also don't check for the new error cases you've added.

So I really think this is quite questionable, and those cases should
probably have been done entirely inside ovlfs rather than polluting
the cases that don't care and don't check.

                 Linus