From: hch@infradead.org (Christoph Hellwig)
To: linux-security-module@vger.kernel.org
Subject: [PATCH 3/3] ima: use fs method to read integrity data (updated patch description)
Date: Sun, 17 Sep 2017 08:37:55 -0700 [thread overview]
Message-ID: <20170917153755.GA21193@infradead.org> (raw)
In-Reply-To: <CA+55aFyrZ=YsfNc1vp=vArNgotLXGPr4F6uZiz22Uj2XHGUvaw@mail.gmail.com>
On Sun, Sep 17, 2017 at 08:28:40AM -0700, Linus Torvalds wrote:
> The issue is that somebody else can come in - using direct IO - at the
> same time as the first person is collecting measurements, and thus
> race with the collector.
>
> So now the measurements are not trustworthy any more.
Yes. And it's always been that way with IMA.
> .. and *my* point is that it's the wrong lock for actually checking
> integrity (it doesn't actually guarantee exclusion, even though in
> practice it's almost always the case), and so we're adding a nasty
> callback that in 99% of all cases is the same as the normal read, and
> we *could* have just added it with a RWF flag instead.
>
> Is there some reason why integrity has to use that particular lock
> that is so inconvenient for the filesystems it wants to check?
I'll have to defer that to Mimi - I just jumped into this whole mess
to help fixing the deadlocks we saw on XFS and NFS.
Unfortunately the whole security code is a giant mess that doesn't
document assumptions, threat models or gets any sort of verification
of those through automated testing.
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next prev parent reply other threads:[~2017-09-17 15:37 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-15 4:58 [PATCH 0/3] ima: only call integrity_kernel_read to calc file hash Mimi Zohar
2017-09-15 4:58 ` [PATCH 1/3] vfs: constify path argument to kernel_read_file_from_path Mimi Zohar
2017-09-15 18:37 ` Linus Torvalds
2017-09-15 4:58 ` [PATCH 2/3] integrity: replace call to integrity_read_file with kernel version Mimi Zohar
2017-09-15 4:58 ` [PATCH 3/3] ima: use fs method to read integrity data Mimi Zohar
[not found] ` <CA+55aFwVujvsdaq09O216u-uBbBbo5i_1d6aw3ksottR_uiJ6w@mail.gmail.com>
2017-09-15 9:04 ` Mimi Zohar
2017-09-15 9:09 ` Mimi Zohar
2017-09-15 18:05 ` Linus Torvalds
2017-09-15 14:49 ` Christoph Hellwig
2017-09-15 15:21 ` Mimi Zohar
2017-09-15 20:25 ` [PATCH 3/3] ima: use fs method to read integrity data (updated patch description) Mimi Zohar
2017-09-16 18:20 ` Linus Torvalds
2017-09-17 5:47 ` Mimi Zohar
2017-09-17 15:17 ` Christoph Hellwig
2017-09-17 15:28 ` Linus Torvalds
2017-09-17 15:37 ` Christoph Hellwig [this message]
2017-09-17 16:15 ` Mimi Zohar
2017-09-17 16:34 ` Linus Torvalds
2017-09-17 16:38 ` Al Viro
2017-09-18 9:19 ` Steven Whitehouse
2017-09-18 10:13 ` Jan Kara
2017-09-18 14:55 ` Mimi Zohar
2017-09-24 22:55 ` Mimi Zohar
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