On Thu, 2012-01-12 at 11:49 -0500, Simo Sorce wrote:
> On Tue, 2012-01-10 at 14:33 -0500, Simo Sorce wrote:
> > On Tue, 2012-01-10 at 10:15 -0500, Simo Sorce wrote:
> > > > Sure, we can talk about it. I'm looking at it from the
users'
> > > > perspectives, who I think would generally expect (and be alright
> > >
> > > with)
> > >
> > > > the fast cache being emptied on service restart. Since we still
> > > > have
> > >
> > > the
> > >
> > > > not-quite-as-fast persistent LDB cache, I think the gain isn't
> > > > worth
> > >
> > > the
> > >
> > > > user confusion.
> > >
> > > Ok, I think I can understand this, it will also simplify the code I
> > > guess so I'll change the patch.
> >
> > Attached new set of patches.
> >
> > I changed the init code to always create a new cache file on restart,
> > incidentally this also got rid of the stat() call, so that problem has
> > been put to rest permanently :)
> >
> > I also changed all functions to use errno_t as the return type in their
> > declaration when they return a errno code.
> >
> > I think all the suggestions seen in the thread so far have been
> > implemented as requested at this point, with the exception of the part
> > where I should implement and use new options as that required
> > additional code instead of mere refactoring. I will add those features
> > in a later rebase.
>
> New revision.
>
> I removed bootid from the cache file header, given we recreate the file
> every time sssd restarts it was useles.
>
> I replaced it with a seed, and made the seed used in the hash table
> randomly regenerated every time the hash table is recreated.
>
> This is used to avoid collision based attacks [1].
>
> Simo.
>
> [1]
https://lwn.net/Articles/474912/
I started looking at these last night. I have yet to complete a full
review, but I'm attaching a set of patches rebased atop the current
master so several of us can start reviewing.
Ok, I finished the review. I am fine with these patches in general, I have just
a few comments and/or questions:
Why only one hash table for both name and uidkey? I think using two would make
things a little bit more simple and fast (of course a tradeoff would be
slightly higher memory consumption).
responder/nss/nsssrv_mmap_cache.c:220
- this condition is unnecessarry because of the condition on line 208
responder/nss/nsssrv_mmap_cache.c:242
- the assignment is redundant
responder/nss/nsssrv_mmap_cache.c:275
- why this condition? I think the following while will cover it
responder/nss/nsssrv_mmap_cache.c:516
- sizeof(uint32_t) -> sizeof(h.status)
responder/nss/nsssrv_mmap_cache.c:517
- sizeof(uint32_t) -> sizeof(h.status)
responder/nss/nsssrv_mmap_cache.c:561
- shouldn't the umask better be 0133?
close vs. munmap
Just out of curiosity: does it matter which should be first? I found two places
in the code where the order is different:
sss_client/nss_mc_common.c:146
responder/nss/nsssrv_mmap_cache.c:717
That's all from my side. As I've said, my comments are rather minor things and
suggestions, so in general I give these patches a green light.
Thanks
Jan