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From: David Miller <>
Subject: Re: [PATCH v8 0/2] KEYS: Read keys to internal buffer & then copy to userspace
Date: Wed, 25 Mar 2020 19:30:56 -0700 (PDT)
Message-ID: <> (raw)
In-Reply-To: <>

From: Waiman Long <>
Date: Sat, 21 Mar 2020 21:11:23 -0400

> The current security key read methods are called with the key semaphore
> held.  The methods then copy out the key data to userspace which is
> subjected to page fault and may acquire the mmap semaphore. That can
> result in circular lock dependency and hence a chance to get into
> deadlock.
> To avoid such a deadlock, an internal buffer is now allocated for getting
> out the necessary data first. After releasing the key semaphore, the
> key data are then copied out to userspace sidestepping the circular
> lock dependency.
> The keyutils test suite was run and the test passed with these patchset
> applied without any falure.

Who will integrate these changes?

  parent reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-22  1:11 Waiman Long
2020-03-22  1:11 ` [PATCH v8 1/2] KEYS: Don't write out to userspace while holding key semaphore Waiman Long
2020-03-22  1:11 ` [PATCH v8 2/2] KEYS: Avoid false positive ENOMEM error on key read Waiman Long
2020-03-26  2:30 ` David Miller [this message]
2020-03-26 18:12 ` [PATCH v8 0/2] KEYS: Read keys to internal buffer & then copy to userspace David Howells
2020-03-26 22:37   ` Jarkko Sakkinen

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