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From: Christoph Hellwig <hch@infradead.org>
To: James Morris <jmorris@namei.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	LSM List <linux-security-module@vger.kernel.org>,
	Mimi Zohar <zohar@linux.vnet.ibm.com>,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [GIT PULL] Security subsystem updates for 4.14
Date: Fri, 8 Sep 2017 00:09:43 -0700	[thread overview]
Message-ID: <20170908070943.GA26549@infradead.org> (raw)
In-Reply-To: <alpine.LRH.2.21.1709081448090.7880@namei.org>

The reason why I send out the original version of this patch
is because IMA used to call ->read under i_rwsem, and that deadlocked
on XFS and NFS, or ext3/4 with DAX.  The call path for that is

process_measurement (takes i_rwsem)
  -> ima_collect_measurement
    -> ima_calc_file_hash
       -> ima_calc_file_ahash / ima_calc_file_shash
         -> ima_calc_file_hash_atfm / ima_calc_file_hash_tfm
	   -> integrity_kernel_read

ima_check_last_writer (takes i_rwsem)
  -> ima_update_xattr
    -> ima_collect_measurement
       -> (as above)

But yes, for the init-time integrity_read_file this is incorrect.
It never tripped up, and I explicitly added the lockdep annotations
so that anything would show up, and it's been half a year since
I sent that first RFC patch..

WARNING: multiple messages have this Message-ID (diff)
From: hch@infradead.org (Christoph Hellwig)
To: linux-security-module@vger.kernel.org
Subject: [GIT PULL] Security subsystem updates for 4.14
Date: Fri, 8 Sep 2017 00:09:43 -0700	[thread overview]
Message-ID: <20170908070943.GA26549@infradead.org> (raw)
In-Reply-To: <alpine.LRH.2.21.1709081448090.7880@namei.org>

The reason why I send out the original version of this patch
is because IMA used to call ->read under i_rwsem, and that deadlocked
on XFS and NFS, or ext3/4 with DAX.  The call path for that is

process_measurement (takes i_rwsem)
  -> ima_collect_measurement
    -> ima_calc_file_hash
       -> ima_calc_file_ahash / ima_calc_file_shash
         -> ima_calc_file_hash_atfm / ima_calc_file_hash_tfm
	   -> integrity_kernel_read

ima_check_last_writer (takes i_rwsem)
  -> ima_update_xattr
    -> ima_collect_measurement
       -> (as above)

But yes, for the init-time integrity_read_file this is incorrect.
It never tripped up, and I explicitly added the lockdep annotations
so that anything would show up, and it's been half a year since
I sent that first RFC patch..
--
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  reply	other threads:[~2017-09-08  7:09 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-04 10:29 [GIT PULL] Security subsystem updates for 4.14 James Morris
2017-09-04 10:29 ` James Morris
2017-09-07 18:19 ` Linus Torvalds
2017-09-07 18:19   ` Linus Torvalds
2017-09-08  4:48   ` James Morris
2017-09-08  4:48     ` James Morris
2017-09-08  7:09     ` Christoph Hellwig [this message]
2017-09-08  7:09       ` Christoph Hellwig
2017-09-08 17:25       ` Linus Torvalds
2017-09-08 17:25         ` Linus Torvalds
2017-09-08 17:36         ` Paul Moore
2017-09-08 17:36           ` Paul Moore
2017-09-10  4:32           ` James Morris
2017-09-10  4:32             ` James Morris
2017-09-10  4:53             ` James Morris
2017-09-10  4:53               ` James Morris
2017-09-11 22:30             ` Paul Moore
2017-09-11 22:30               ` Paul Moore
2017-09-14 21:09             ` Kees Cook
2017-09-14 21:09               ` Kees Cook
2017-09-14 21:13               ` James Morris
2017-09-14 21:13                 ` James Morris
2017-09-14 21:25                 ` Kees Cook
2017-09-14 21:25                   ` Kees Cook
2017-09-08 19:57         ` James Morris
2017-09-08 19:57           ` James Morris
2017-09-17  7:36           ` Mimi Zohar
2017-09-17  7:36             ` Mimi Zohar
2017-09-10  8:10         ` Christoph Hellwig
2017-09-10  8:10           ` Christoph Hellwig
2017-09-10 14:02           ` Mimi Zohar
2017-09-10 14:02             ` Mimi Zohar
2017-09-11  6:38             ` Christoph Hellwig
2017-09-11  6:38               ` Christoph Hellwig
2017-09-11 21:34               ` Mimi Zohar
2017-09-11 21:34                 ` Mimi Zohar
2017-09-08 22:38     ` Theodore Ts'o
2017-09-08 22:38       ` Theodore Ts'o
2017-09-10  2:08       ` James Morris
2017-09-10  2:08         ` James Morris
2017-09-10  7:13       ` Mimi Zohar
2017-09-10  7:13         ` Mimi Zohar
2017-09-10 12:17         ` Theodore Ts'o
2017-09-10 12:17           ` Theodore Ts'o
2017-09-10  6:46   ` Mimi Zohar
2017-09-10  6:46     ` Mimi Zohar

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