Messages in this thread | | | Subject | Re: xfs: commit 6552321831dc "xfs: remove i_iolock and use i_rwsem in the VFS inode instead" change causes hang | From | Mimi Zohar <> | Date | Sun, 08 Jan 2017 10:03:09 -0500 |
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On Sun, 2017-01-08 at 15:52 +0100, Christoph Hellwig wrote: > On Sun, Jan 08, 2017 at 09:48:44AM -0500, Mimi Zohar wrote: > > IMA takes the i_rwsem (fomerly i_mutex) before reading the file to > > synchronize calculating the file hash and validating the file's > > hash/signature stored as security.ima xattr > > Well, it shouldn't do that. In the I/O path i_rwsem is up to the > fs to use. Various other file systems also take it internally for > reads, although mostly only for direct I/O.
But not normally for a normal file read. For direct I/O, IMA fails the file hash/signature verification, measurement, audit unless the IMA "permit_directio" rule is defined.
> So the answer here is that ima needs to stop playing with i_rwsem.
Unless something has changed recently, to synchronize reading files to calculate the file hash and writing xattrs it has to take the i_rwsem prior to reading the file.
Mimi
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