auditing syscalls made 'by' an inode?

Steve Grubb sgrubb at redhat.com
Fri Jun 8 13:51:25 UTC 2012


On Friday, June 08, 2012 09:35:01 AM Steve Grubb wrote:
> On Thursday, June 07, 2012 06:31:47 PM Peter Moody wrote:
> > Is there anyway to audit syscalls made by a particular, not yet
> > running, application?
> 
> No...its one of the things I've been interested in for a long time. About
> as close as you get is using the selinux process context. But if its
> bin_t...there's a couple thousand processes with the same label.
> 
> > For example, if I'm interested in seeing all
> > exec's by google-chrome, can I do something like the following?
> > 
> > auditctl -a exit,always -F arch=b64 -S execve -F success=1 -F
> > inode=inode-of-chrome
> > 
> > experimenting seems to indicate that will only tell me when
> > inode-of-chrome is exec'd, basically a watch rule.
> > 
> > The sort of inverse of this rule that got me thinking about this
> > initially was auditing a syscall and seeing if it was/wasn't called by
> > a particular program. For example, audting all bind() calls which
> > *aren't* made by chrome (a silly rule to be sure, but just thrown out
> > as a hypothetical)
> > 
> > If it's not possible to do this now, is there interest in adding this
> > feature?
> 
> Yes. I'd be interested in seeing this available. But if you do implement
> it, its more natural to express the rule by process name. But the kernel
> does not do string comparisons. So, what you would likely need to do is
> lookup the path to get the inode, then when it executes a new kind of pid
> rule gets created probably off the list like watches do. There are some
> apps like apache which fork multiple copies and that adds a wrinkle
> because you would want to audit all of them. And then there are 
> threads...

The other thing that was discussed a lot maybe 5 years ago (and I don't think it 
was ever created) was the ability to audit syscalls of a processes children and 
their children...on and on.  I think Al Viro mentioned he had some ideas about 
how to do this. But if you add audit by process name, its only natural to 
optionally track all child processes, too.

Where you might want this is like setting a rule on apache for any EPERM or any 
access to /home. Same could go for bind.

-Steve




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