On Wed, Jan 16, 2013 at 01:08:35PM -0500, Mimi Zohar wrote: > On Wed, 2013-01-16 at 11:34 -0500, Vivek Goyal wrote: > > > I read the comment in ima_bprm_check() being called from > > security_bprm_check(). > > It says that files already open for write can't executed and files already > > open for exec can't be open for writes. That's fine. > > > > I was worried about anonymous pages being modified on swap and then > > faulted back in. It is not necessarily signature verification but making > > sure signed processes memory is not modified later by any unsigned process > > in anyway. And that includes disabling ptrace too. > > > > So IMA stuff does not do anything to protect against process memory being > > modified using ptrace or by playing tricks with swap. > > > I am not sure what will happen if I can bypass the file system and directly > > write on a disk block and modify executable. (Assuming one can get block > > information somehow). Does anything protect such modification? Will IMA > > detect it? > > Sorry, this is out of scope for IMA. Dmitry has looked into this, but > I'm not sure where it stands at the moment.
Ok, so that's one reason that why I wrote these patcehs. IMA currently is not doing following things to make sure address space of signed images is not modified by others. - Protecting against modifications to pages on swap. - Protecting against modifications by ptrace. - Protecting against modifications which bypassed filesystem and directly wrote to the block. Locking down all the pages of signed binaries in memory hopefully should solve above problems. Thanks Vivek -- 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/
