linux-kernel - Re: Alloc cap limit for 9p xattrs (Was: WARNING in __alloc_frozen_pages

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: <CAHk-=wiH+FmLBGKk86ung9Qbrwd0S-7iAnEAbV9QDvX5vAjL7A@mail.gmail.com>
Date: Wed, 11 Dec 2024 13:32:26 -0800
From: Linus Torvalds <torvalds@...ux-foundation.org>
To: asmadeus@...ewreck.org
Cc: Leo Stone <leocstone@...il.com>, 
	syzbot+03fb58296859d8dbab4d@...kaller.appspotmail.com, ericvh@...il.com, 
	ericvh@...nel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux_oss@...debyte.com, lucho@...kov.net, 
	syzkaller-bugs@...glegroups.com, v9fs-developer@...ts.sourceforge.net, 
	v9fs@...ts.linux.dev, viro@...iv.linux.org.uk, 
	Fedor Pchelkin <pchelkin@...ras.ru>, Seth Forshee <sforshee@...nel.org>, 
	Christian Brauner <brauner@...nel.org>
Subject: Re: Alloc cap limit for 9p xattrs (Was: WARNING in __alloc_frozen_pages_noprof)

On Wed, 11 Dec 2024 at 13:04, <asmadeus@...ewreck.org> wrote:
>
> Christian Schoenebeck's suggestion was something like this -- I guess
> that's good enough for now and won't break anything (e.g. ACLs bigger
> than XATTR_SIZE_MAX), so shall we go with that instead?

Please use XATTR_SIZE_MAX. The KMALLOC_MAX_SIZE limit seems to make no
sense in this context.

Afaik the VFS layer doesn't allow getting an xattr bigger than
XATTR_SIZE_MAX anyway, and would return E2BIG for them later
regardless, so returning anything bigger wouldn't work anyway, even if
p9 tried to return such a thing up to some bigger limit.

No?

           Linus