Re: Sycall Rules vs Watch Rules

[Steve Grubb <sgrubb@redhat.com>]

On Thursday, September 21, 2023 4:02:49 PM EDT Amjad Gabbar wrote:
> > The best solution would be a kernel modification so that there are no
> > mismatched lists.
>
> I agree as well....This would be the cleanest solution. This would also
> solve the userspace problem of maintaining different lists which can get
> out of hand fairly quickly.

After looking into this, a kernel patch would also not work well. It has to 
be arch specific
 
> > I guess we can warn on that to rewrite in syscall notation.
> 
> We certainly should. I think the user should know that there is a
> performance cost associated with watches and we should explicitly mention
> how it can be optimized in the manpages also. The reason being I am pretty
> sure, numerous users/repos still do make use of the -w notation and we do
> want to let them know the issue here. We also need to make quite a few
> changes to the manpages also regarding this. Because, initially even I was
> very confused when reading the man pages and seeing the actual
> implementation of and results were not quite in sync.

I have made the changes to the master and audit-3.1-maint branches. Please 
everyone concerned give them tests. The short of it is that if you use the '-
w' notation for watches, it will remain the same and slower. If you use the 
syscall notation without "-F arch", you will get a warning that it cannot be 
optimized without adding "-Farch". If you add "-F arch", you will possibly 
need one for both arches which means doubling the rules. If you do not want 
to double the rules, you might place a syscall rule for any 32 system call 
(21-no32bit.rules). Or you can leave it as is and not care. The sample rules 
and all man pages have been updated.

Please, let me know if this works out better.

-Steve


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