Messages in this thread | | | Subject | Re: [PATCH] vfs: fix IMA lockdep circular locking dependency | From | Mimi Zohar <> | Date | Tue, 15 May 2012 16:07:26 -0400 |
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On Tue, 2012-05-15 at 15:42 -0400, Eric Paris wrote: > On Tue, May 15, 2012 at 2:41 PM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: > > On Tue, May 15, 2012 at 10:19 AM, Linus Torvalds > > <torvalds@linux-foundation.org> wrote: > >> > >> - move the whole call to security_file_mmap() to outside the > >> mmap_sem, and test the *suggested* address (which is not the same as > >> the final address) > > > > Actually, I think I have a simpler approach. > > > > We already actually have two *different* security_file_mmap() calls: > > it's just that currently the difference is shown by the last argument > > to the function ("addr_only"). > > I'm the one who introduced that bit of horrific. I originally did it > the way you describe and someone (it was a long time ago, and I think > it was Ted Tso, but I am probably very very wrong on that) ask me to > tack it on the end like this. I'd be very happy with the split you > describe. > > I'd rather not, however, move the address call site like you described > above, as I don't want to allow NULL + ~MAP_FIXED to be tested until > it has been resolved to a real address. I don't want someone to find > a way to get the kernel to choose 4096 and avoid the check....
If the security_file_mmap() moves to before taking the mmap_sem and the new security_mmap_addr() hook would be at the current security_file_mmap() location, I don't see the problem. The addr test would remain in the same place.
> Mimi, would you like to do this (slightly) larger change? Should I?
np, I'll make the changes.
Mimi
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