linux-kernel - Re: [PATCH 4/6] fuse: enable close

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: <53FB55E3.1050806@parallels.com>
Date:	Mon, 25 Aug 2014 19:27:31 +0400
From:	Maxim Patlasov <mpatlasov@...allels.com>
To:	Miklos Szeredi <miklos@...redi.hu>
CC:	fuse-devel <fuse-devel@...ts.sourceforge.net>,
	Anand Avati <avati@...ster.org>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/6] fuse: enable close_wait synchronous release

On 08/22/2014 06:04 PM, Miklos Szeredi wrote:
> On Thu, Aug 21, 2014 at 6:09 PM, Maxim Patlasov <MPatlasov@...allels.com> wrote:
>> The patch enables the feature by passing 'true' to fuse_file_put in
>> fuse_release_common.
>>
>> Previously, this was safe only in special cases when we sure that
>> multi-threaded userspace won't deadlock if we'll synchronously send
>> FUSE_RELEASE in the context of read-ahead or write-back callback. Now, it's
>> always safe because callbacks don't send requests to userspace anymore.
> But we do want to make this privileged, as there are unlikely but
> possible DoS scenarios with a sync release.

The latest patch of the set implements DISABLE_SYNC_RELEASE mount 
option. We can instrument fusermount to use the option by default for 
unprivileged mounts (allowing system administrator to configure it like 
"user_allow_other"). Do you have a better way to implement DoS 
protection in mind?

Thanks,
Maxim
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/