* [iptables PATCH] xtables: Fix typo in nft_rebuild_cache()
@ 2019-05-14 8:51 Phil Sutter
2019-05-14 11:45 ` Phil Sutter
0 siblings, 1 reply; 2+ messages in thread
From: Phil Sutter @ 2019-05-14 8:51 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: netfilter-devel
Conditional cache flush logic was inverted.
Fixes: 862818ac3a0de ("xtables: add and use nft_build_cache")
Signed-off-by: Phil Sutter <phil@nwl.cc>
---
iptables/nft.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/iptables/nft.c b/iptables/nft.c
index 6354b7e8e72fe..83e0d9a69b37c 100644
--- a/iptables/nft.c
+++ b/iptables/nft.c
@@ -1541,7 +1541,7 @@ void nft_build_cache(struct nft_handle *h)
void nft_rebuild_cache(struct nft_handle *h)
{
- if (!h->have_cache)
+ if (h->have_cache)
flush_chain_cache(h, NULL);
__nft_build_cache(h);
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [iptables PATCH] xtables: Fix typo in nft_rebuild_cache()
2019-05-14 8:51 [iptables PATCH] xtables: Fix typo in nft_rebuild_cache() Phil Sutter
@ 2019-05-14 11:45 ` Phil Sutter
0 siblings, 0 replies; 2+ messages in thread
From: Phil Sutter @ 2019-05-14 11:45 UTC (permalink / raw)
To: Florian Westphal; +Cc: Pablo Neira Ayuso, netfilter-devel
Hi,
On Tue, May 14, 2019 at 10:51:33AM +0200, Phil Sutter wrote:
> Conditional cache flush logic was inverted.
>
> Fixes: 862818ac3a0de ("xtables: add and use nft_build_cache")
> Signed-off-by: Phil Sutter <phil@nwl.cc>
> ---
> iptables/nft.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/iptables/nft.c b/iptables/nft.c
> index 6354b7e8e72fe..83e0d9a69b37c 100644
> --- a/iptables/nft.c
> +++ b/iptables/nft.c
> @@ -1541,7 +1541,7 @@ void nft_build_cache(struct nft_handle *h)
>
> void nft_rebuild_cache(struct nft_handle *h)
> {
> - if (!h->have_cache)
> + if (h->have_cache)
> flush_chain_cache(h, NULL);
>
> __nft_build_cache(h);
So with this change I broke your transaction reload logic. The problem
is that data in h->obj_list potentially sits in cache, too. At least
rules have to be there so insert with index works correctly. If the
cache is flushed before regenerating the batch, use-after-free occurs
which crashes the program.
We need to either keep the old cache around or keep locally generated
entries when flushing (which might require more intelligent cache
update, too).
I also have a fix for your testcase, will submit that in a minute as
well.
Cheers, Phil
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2019-05-14 11:45 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-14 8:51 [iptables PATCH] xtables: Fix typo in nft_rebuild_cache() Phil Sutter
2019-05-14 11:45 ` Phil Sutter
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).