Re: [PATCH 2/2] auvirt: Remove workaround for VM name searching
On Thursday, February 09, 2012 12:51:24 PM Marcelo Cerri wrote:
On 02/09/2012 11:35 AM, Steve Grubb wrote:
> On Thursday, February 09, 2012 08:22:34 AM Marcelo Cerri wrote:
>> Thanks for your explanation. I hadn't notice how escaped fields work.
>>
>> Regarding the search algorithm fix, sorry but it is not clear to me
>> where you meant to say to add the type check and the escape. Did you
>> mean inside the ausearch_add_item or in the function which is calling
>> the ausearch_add_item function?
>
> I think its best to put it inside the function so that app writers do not
> have to think about it. They just pass a string and its fixed up. I was
> also thinking about the alternative, which is to decode the fields
> during search and then compare. But this would be slower because we
> decode every field value whether it matches or not. So, we can just
> encode the item being searched for and then compare raw values. I
> suppose the man page should clarify this for app writers just in case.
Digging into auparse source code, I noticed there is an "interpreted"
version of ausearch_add_item (ausearch_add_interpreted_item). I could
get matches for the "vm" field using this function.
Sure. That makes it easier. :)
Do you think that it's still necessary to change
ausearch_add_item?
I guess not.
>> I'll submit a patch to libvirt instead and then update
auvirt.
>
> I wished I caught that sooner, too. As for auvirt, since you know vm is
> an escaped field, you don't actually need to put the "if" statement
to
> check its type. You can just call the interpret function unconditionally
> and use its output.
Probably it'll also be necessary to add the "old-net" and
"new-net"
fields to the typetab.h file.
Why? They look like MAC addresses to me.
If a field isn't in typetab.h, what type is considered for it? Is
it considered
just a regular string?
Yes. Generally to need to be in the type tab there might need to some kind of
transformation from a binary form into a more readable presentation. For
example, uid=500, what does 500 mean? exit=-2, what does -2 mean? In terms of
transformations, areas that I think needs more work is translating some of the
syscall parameters so ausearch output is more meaningful. But this is low on the
list of things to do.
I guess at this point you can make a simple patch to auvirt that cleans it up.
-Steve