From: Jarkko Sakkinen <jarkko@kernel.org>
To: Chengfeng Ye <nicoyip.dev@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
Paul Moore <paul@paul-moore.com>,
James Morris <jmorris@namei.org>,
"Serge E . Hallyn" <serge@hallyn.com>,
keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v4 2/2] keys: Serialize ownership transfers with key accounting
Date: Wed, 14 Oct 2026 14:44:22 +0300 [thread overview]
Message-ID: <as9rFtolVVn0NVD1@kernel.org> (raw)
In-Reply-To: <as9pUYoOmLI2l5oB@kernel.org>
On Wed, Oct 14, 2026 at 02:36:53PM +0300, Jarkko Sakkinen wrote:
> On Tue, Oct 13, 2026 at 05:03:58PM +0800, Chengfeng Ye wrote:
> > Protecting individual accesses to key->user does not make ownership
> > transfers atomic with accounting updates. keyctl_chown_key() holds
> > key->sem, but instantiation is serialized by key_construction_mutex and
> > need not hold that semaphore. KEY_LOOKUP_PARTIAL also permits chown of
> > an uninstantiated key.
> >
> > The instantiated-key count can therefore be charged to the wrong owner:
> >
> > instantiate keyctl_chown_key()
> > increment old->nikeys
> > observe KEY_IS_UNINSTANTIATED
> > skip the nikeys transfer
> > replace key->user
> > mark key instantiated
>
>
> Same here there's another below.
This was also asked last time. Actually last time (since I missed the
spurious comment), this was the only thing that wask from you.
Br, Jarkko
next prev parent reply other threads:[~2026-10-14 11:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 8:40 [PATCH v4 0/2] keys: Fix quota-owner reads and ownership accounting Chengfeng Ye
2026-10-13 9:03 ` [PATCH v4 1/2] keys: Protect quota-owner reads in namespace filters Chengfeng Ye
2026-10-13 9:28 ` sashiko-bot
2026-10-14 11:15 ` Jarkko Sakkinen
2026-10-14 11:34 ` Jarkko Sakkinen
2026-10-13 9:03 ` [PATCH v4 2/2] keys: Serialize ownership transfers with key accounting Chengfeng Ye
2026-10-13 9:39 ` sashiko-bot
2026-10-14 11:36 ` Jarkko Sakkinen
2026-10-14 11:44 ` Jarkko Sakkinen [this message]
2026-10-13 17:43 ` [PATCH v4 0/2] keys: Fix quota-owner reads and ownership accounting Jarkko Sakkinen
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