Messages in this thread | | | From | Tvrtko Ursulin <> | Subject | Re: what's the replace for the big kernel lock after kernel version 2.6.39 for system call. | Date | Wed, 30 Nov 2011 09:44:27 +0000 |
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On Tuesday 29 Nov 2011 21:41:36 Al Viro wrote: > On Mon, Nov 28, 2011 at 01:03:07AM -0800, Wen Yan Xin wrote: > > Hi all, > > > > I have a trouble of working on kernel 2.6.39 and later. Originally when > > our kernel module startups, it hooks some file system call, like > > sys_open... , and the big kernel lock - lock_kernel() - will be held > > before creating the hook to prevent user application use system calls, > > and be released after the hook created. > > > > > > But after the kernel 2.6.39, the big kernel lock has been removed. I'm > > thinking there should be one or more lock that should be used. > > > > So, my question is which lock should be held now, when we hook the system > > call of file system? > > > > I'd really appreciate your answer in advance. > > 1) your rootkit has always been racy; taking BKL does *NOT* prevent another > CPU from entering a system call. > > 2) none; just don't do it.
Hi Al,
Why not be a nice guy when you already took the effort of replying and mention fanotify? Because I am sure you know the history and when you see a security vendor asking these things, you never know, maybe it fits their requirements. Maybe it is not your favourite thing as well, but not a reason not to mention it.
And strictly speaking, rootkits actively try to hide themselves hence whatever unsafe, ugly and wrong stuff they might have it is not a rootkit. :)
Regards,
Tvrtko
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