On Fri, Apr 25, 2014 at 01:45:17PM -0700, Eric W. Biederman wrote: > IMA-appraisal is fundamentally broken because I can take a mandatory > file lock and prevent IMA-apprasial. > > Using kernel_read is what allows this. > > > Isn't it a clear motivating case??? > > kernel_read is not appropriate for IMA use. The rest of this is just > the messenger. > > IMA needs to use a cousin of kernel_read that operates at a lower level > than vfs_read. A function that all of the permission checks and the > fsnotify work.
It's worse than that, actually ;-/ IMA hooks in __fput() have interesting interplay with revoke-related stuff as well. Another very messy thing in the same area is that it actually does ->read() from under ->i_mutex, leading to all kinds of interesting locking issues... I doubt that your "let's open-code vfs_read() guts" would be a good idea; if nothing else, it might make more sense to make rw_verify_area() skip the mandlock and security theatre when called in such situation. What a mess... ;-/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/