From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Dave Chinner <david@fromorbit.com>,
LSM List <linux-security-module@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-integrity@vger.kernel.org,
Christoph Hellwig <hch@infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jan Kara <jack@suse.cz>, "Theodore Ts'o" <tytso@mit.edu>
Subject: Re: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date: Thu, 28 Sep 2017 20:26:15 -0700 [thread overview]
Message-ID: <CA+55aFzZXBBn+HgLD_4C6DgpSiOMAP2WzuGPWRUkEXZJuz+QBQ@mail.gmail.com> (raw)
In-Reply-To: <1506649980.5691.100.camel@linux.vnet.ibm.com>
On Thu, Sep 28, 2017 at 6:53 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
>
> The locking issue isn't with validating the file hash, but with the
> setxattr, chmod, chown syscalls. Each of these syscalls takes the
> i_rwsem exclusively before IMA (or EVM) is called.
Read my email again.
> In setxattr, chmod, chown syscalls, IMA (and EVM) are called after the
> i_rwsem is already taken. So the locking would be:
>
> lock: i_rwsem
> lock: iint->mutex
No.
Two locks. One inner, one outer. Only the actual ones that calculates
the hash would take the outer one. Read my email.
Linus
WARNING: multiple messages have this Message-ID (diff)
From: torvalds@linux-foundation.org (Linus Torvalds)
To: linux-security-module@vger.kernel.org
Subject: [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively
Date: Thu, 28 Sep 2017 20:26:15 -0700 [thread overview]
Message-ID: <CA+55aFzZXBBn+HgLD_4C6DgpSiOMAP2WzuGPWRUkEXZJuz+QBQ@mail.gmail.com> (raw)
In-Reply-To: <1506649980.5691.100.camel@linux.vnet.ibm.com>
On Thu, Sep 28, 2017 at 6:53 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
>
> The locking issue isn't with validating the file hash, but with the
> setxattr, chmod, chown syscalls. Each of these syscalls takes the
> i_rwsem exclusively before IMA (or EVM) is called.
Read my email again.
> In setxattr, chmod, chown syscalls, IMA (and EVM) are called after the
> i_rwsem is already taken. So the locking would be:
>
> lock: i_rwsem
> lock: iint->mutex
No.
Two locks. One inner, one outer. Only the actual ones that calculates
the hash would take the outer one. Read my email.
Linus
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next prev parent reply other threads:[~2017-09-29 3:26 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 12:39 [RFC PATCH 0/3] define new read_iter file operation rwf flag Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 12:39 ` [RFC PATCH 1/3] fs: define new read_iter " Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 13:54 ` Matthew Wilcox
2017-09-28 13:54 ` Matthew Wilcox
2017-09-28 14:33 ` Mimi Zohar
2017-09-28 14:33 ` Mimi Zohar
2017-09-28 15:51 ` Linus Torvalds
2017-09-28 15:51 ` Linus Torvalds
2017-09-28 12:39 ` [RFC PATCH 2/3] integrity: use call_read_iter to calculate the file hash Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 12:39 ` [RFC PATCH 3/3] fs: detect that the i_rwsem has already been taken exclusively Mimi Zohar
2017-09-28 12:39 ` Mimi Zohar
2017-09-28 22:02 ` Dave Chinner
2017-09-28 22:02 ` Dave Chinner
2017-09-28 23:39 ` Linus Torvalds
2017-09-28 23:39 ` Linus Torvalds
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:12 ` Mimi Zohar
2017-09-29 0:33 ` Linus Torvalds
2017-09-29 0:33 ` Linus Torvalds
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 1:53 ` Mimi Zohar
2017-09-29 3:26 ` Linus Torvalds [this message]
2017-09-29 3:26 ` Linus Torvalds
2017-10-01 1:33 ` Eric W. Biederman
2017-10-01 1:33 ` Eric W. Biederman
[not found] ` <CA+55aFx726wT4VprN-sHm6s8Q_PV_VjhTBC4goEbMcerYU1Tig@mail.gmail.com>
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 12:08 ` Mimi Zohar
2017-10-01 18:41 ` Linus Torvalds
2017-10-01 18:41 ` Linus Torvalds
2017-10-01 22:34 ` Dave Chinner
2017-10-01 22:34 ` Dave Chinner
2017-10-01 23:15 ` Linus Torvalds
2017-10-01 23:15 ` Linus Torvalds
2017-10-02 3:54 ` Dave Chinner
2017-10-02 3:54 ` Dave Chinner
2017-10-01 23:42 ` Mimi Zohar
2017-10-01 23:42 ` Mimi Zohar
2017-10-01 23:42 ` Mimi Zohar
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 3:25 ` Eric W. Biederman
2017-10-02 12:25 ` Mimi Zohar
2017-10-02 12:25 ` Mimi Zohar
2017-10-02 12:25 ` Mimi Zohar
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 4:35 ` Dave Chinner
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:09 ` Mimi Zohar
2017-10-02 12:43 ` Jeff Layton
2017-10-02 12:43 ` Jeff Layton
2017-10-01 22:06 ` Eric W. Biederman
2017-10-01 22:06 ` Eric W. Biederman
2017-10-01 22:20 ` Linus Torvalds
2017-10-01 22:20 ` Linus Torvalds
2017-10-01 23:54 ` Mimi Zohar
2017-10-01 23:54 ` Mimi Zohar
2017-10-01 23:54 ` Mimi Zohar
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