netdev - nft hash set expansion problem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 08 Feb 2015 13:38:59 -0600
From:	Josh Hunt <johunt@...mai.com>
To:	Thomas Graf <tgraf@...g.ch>
CC:	Pablo Neira Ayuso <pablo@...filter.org>, kaber@...sh.net,
	netdev@...r.kernel.org, netfilter-devel@...r.kernel.org
Subject: nft hash set expansion problem

Nft hash sets are unable to expand past the initial # of buckets. This 
is b/c nft hash sets don't define the max_shift parameter and so 
rht_grow_above_75():

         return atomic_read(&ht->nelems) > (new_size / 4 * 3) &&
                (ht->p.max_shift && atomic_read(&ht->shift) < 
ht->p.max_shift);

can't return true.

It's not clear to me if this is intentional; requiring users of 
rhashtables define a max_shift in order to support expansion, or a bug 
in the grow decision function?

Here's a possible fix if it's the latter. Let me know and I can submit 
something formal if that's the case.

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index e96fc00..2c51617 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -250,7 +250,7 @@ bool rht_grow_above_75(const struct rhashtable *ht, 
size_t new_size)
  {
         /* Expand table when exceeding 75% load */
         return atomic_read(&ht->nelems) > (new_size / 4 * 3) &&
-              (ht->p.max_shift && atomic_read(&ht->shift) < 
ht->p.max_shift);
+              (ht->p.max_shift ? atomic_read(&ht->shift) < 
ht->p.max_shift : 1);
  }
  EXPORT_SYMBOL_GPL(rht_grow_above_75);

Thanks
Josh


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html