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 08:17:57 -0700 [thread overview]
Message-ID: <20170917151757.GA14262@infradead.org> (raw)
In-Reply-To: <CA+55aFxmeff53zeioTiQY6m=F18ekgX1-HWZyQUor=NJYrxM9A@mail.gmail.com>
On Sat, Sep 16, 2017 at 11:20:47AM -0700, Linus Torvalds wrote:
> Sure, generic_file_write_iter() does take that lock exclusively, but
> not everybody uses generic_file_write_iter() at all for writing.
>
> For example, xfs still uses that i_rwsem, but for block-aligned writes
> it will only get it shared. And I'm not convinced some other
> filesystem might not end up using some other lock entirely.
Only for direct I/O, and IMA and direct I/O don't work together.
>From ima_collect_measurement:
if (file->f_flags & O_DIRECT) {
audit_cause = "failed(directio)";
result = -EACCES;
goto out;
}
(and yes, it should be checking for IOCB_DIRECT to avoid racy
f_flags manipulations, but that's another issue)
> The filesystem can do its own locking, and I'm starting to think that
> it would be better to just pass this "this is an integrity read" down
> to the filesystem, and expect the filesystem to do the locking based
> on that.
Well, that's exactly the point of the new ->integrity_read routine
I proposed and prototype. The important thing is that it is called
with i_rwsem held because code mugh higher in the chain already
acquired it, but except for that it's entirely up to the file system.
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next prev parent reply other threads:[~2017-09-17 15:17 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 [this message]
2017-09-17 15:28 ` Linus Torvalds
2017-09-17 15:37 ` Christoph Hellwig
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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