[PATCH net 0/3] Netfilter fixes for net

[PATCH net 0/3] Netfilter fixes for net

[Pablo Neira Ayuso]

Hi,

The following patchset contains Netfilter fixes for net:

1) Restore ctnetlink zero mark in events and dump, from Ivan Delalande.

2) Fix deadlock due to missing disabled bh in tproxy, from Florian Westphal.

3) Safer maximum chain load in conntrack, from Eric Dumazet.

Please, pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git

Thanks.

----------------------------------------------------------------

The following changes since commit 528125268588a18a2f257002af051b62b14bb282:

  Merge branch 'nfp-ipsec-csum' (2023-03-03 08:28:44 +0000)

are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git HEAD

for you to fetch changes up to c77737b736ceb50fdf150434347dbd81ec76dbb1:

  netfilter: conntrack: adopt safer max chain length (2023-03-07 10:58:06 +0100)

----------------------------------------------------------------
Eric Dumazet (1):
      netfilter: conntrack: adopt safer max chain length

Florian Westphal (1):
      netfilter: tproxy: fix deadlock due to missing BH disable

Ivan Delalande (1):
      netfilter: ctnetlink: revert to dumping mark regardless of event type

 include/net/netfilter/nf_tproxy.h    |  7 +++++++
 net/ipv4/netfilter/nf_tproxy_ipv4.c  |  2 +-
 net/ipv6/netfilter/nf_tproxy_ipv6.c  |  2 +-
 net/netfilter/nf_conntrack_core.c    |  4 ++--
 net/netfilter/nf_conntrack_netlink.c | 14 +++++++-------
 5 files changed, 18 insertions(+), 11 deletions(-)

[PATCH net 1/3] netfilter: ctnetlink: revert to dumping mark regardless of event type

[Pablo Neira Ayuso]

From: Ivan Delalande <colona@arista.com>

It seems that change was unintentional, we have userspace code that
needs the mark while listening for events like REPLY, DESTROY, etc.
Also include 0-marks in requested dumps, as they were before that fix.

Fixes: 1feeae071507 ("netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark")
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_netlink.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index c11dff91d52d..bfc3aaa2c872 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -328,11 +328,12 @@ ctnetlink_dump_timestamp(struct sk_buff *skb, const struct nf_conn *ct)
 }
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
+static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct,
+			       bool dump)
 {
 	u32 mark = READ_ONCE(ct->mark);
 
-	if (!mark)
+	if (!mark && !dump)
 		return 0;
 
 	if (nla_put_be32(skb, CTA_MARK, htonl(mark)))
@@ -343,7 +344,7 @@ static int ctnetlink_dump_mark(struct sk_buff *skb, const struct nf_conn *ct)
 	return -1;
 }
 #else
-#define ctnetlink_dump_mark(a, b) (0)
+#define ctnetlink_dump_mark(a, b, c) (0)
 #endif
 
 #ifdef CONFIG_NF_CONNTRACK_SECMARK
@@ -548,7 +549,7 @@ static int ctnetlink_dump_extinfo(struct sk_buff *skb,
 static int ctnetlink_dump_info(struct sk_buff *skb, struct nf_conn *ct)
 {
 	if (ctnetlink_dump_status(skb, ct) < 0 ||
-	    ctnetlink_dump_mark(skb, ct) < 0 ||
+	    ctnetlink_dump_mark(skb, ct, true) < 0 ||
 	    ctnetlink_dump_secctx(skb, ct) < 0 ||
 	    ctnetlink_dump_id(skb, ct) < 0 ||
 	    ctnetlink_dump_use(skb, ct) < 0 ||
@@ -831,8 +832,7 @@ ctnetlink_conntrack_event(unsigned int events, const struct nf_ct_event *item)
 	}
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-	if (events & (1 << IPCT_MARK) &&
-	    ctnetlink_dump_mark(skb, ct) < 0)
+	if (ctnetlink_dump_mark(skb, ct, events & (1 << IPCT_MARK)))
 		goto nla_put_failure;
 #endif
 	nlmsg_end(skb, nlh);
@@ -2735,7 +2735,7 @@ static int __ctnetlink_glue_build(struct sk_buff *skb, struct nf_conn *ct)
 		goto nla_put_failure;
 
 #ifdef CONFIG_NF_CONNTRACK_MARK
-	if (ctnetlink_dump_mark(skb, ct) < 0)
+	if (ctnetlink_dump_mark(skb, ct, true) < 0)
 		goto nla_put_failure;
 #endif
 	if (ctnetlink_dump_labels(skb, ct) < 0)
-- 
2.30.2

Re: [PATCH net 1/3] netfilter: ctnetlink: revert to dumping mark regardless of event type

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Pablo Neira Ayuso <pablo@netfilter.org>:

On Tue,  7 Mar 2023 11:04:22 +0100 you wrote:
> From: Ivan Delalande <colona@arista.com>
> 
> It seems that change was unintentional, we have userspace code that
> needs the mark while listening for events like REPLY, DESTROY, etc.
> Also include 0-marks in requested dumps, as they were before that fix.
> 
> Fixes: 1feeae071507 ("netfilter: ctnetlink: fix compilation warning after data race fixes in ct mark")
> Signed-off-by: Ivan Delalande <colona@arista.com>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
> 
> [...]

Here is the summary with links:
  - [net,1/3] netfilter: ctnetlink: revert to dumping mark regardless of event type
    https://git.kernel.org/netdev/net/c/9f7dd42f0db1
  - [net,2/3] netfilter: tproxy: fix deadlock due to missing BH disable
    https://git.kernel.org/netdev/net/c/4a02426787bf
  - [net,3/3] netfilter: conntrack: adopt safer max chain length
    https://git.kernel.org/netdev/net/c/c77737b736ce

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

[PATCH net 2/3] netfilter: tproxy: fix deadlock due to missing BH disable

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

The xtables packet traverser performs an unconditional local_bh_disable(),
but the nf_tables evaluation loop does not.

Functions that are called from either xtables or nftables must assume
that they can be called in process context.

inet_twsk_deschedule_put() assumes that no softirq interrupt can occur.
If tproxy is used from nf_tables its possible that we'll deadlock
trying to aquire a lock already held in process context.

Add a small helper that takes care of this and use it.

Link: https://lore.kernel.org/netfilter-devel/401bd6ed-314a-a196-1cdc-e13c720cc8f2@balasys.hu/
Fixes: 4ed8eb6570a4 ("netfilter: nf_tables: Add native tproxy support")
Reported-and-tested-by: Major Dávid <major.david@balasys.hu>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_tproxy.h   | 7 +++++++
 net/ipv4/netfilter/nf_tproxy_ipv4.c | 2 +-
 net/ipv6/netfilter/nf_tproxy_ipv6.c | 2 +-
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/net/netfilter/nf_tproxy.h b/include/net/netfilter/nf_tproxy.h
index 82d0e41b76f2..faa108b1ba67 100644
--- a/include/net/netfilter/nf_tproxy.h
+++ b/include/net/netfilter/nf_tproxy.h
@@ -17,6 +17,13 @@ static inline bool nf_tproxy_sk_is_transparent(struct sock *sk)
 	return false;
 }
 
+static inline void nf_tproxy_twsk_deschedule_put(struct inet_timewait_sock *tw)
+{
+	local_bh_disable();
+	inet_twsk_deschedule_put(tw);
+	local_bh_enable();
+}
+
 /* assign a socket to the skb -- consumes sk */
 static inline void nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
 {
diff --git a/net/ipv4/netfilter/nf_tproxy_ipv4.c b/net/ipv4/netfilter/nf_tproxy_ipv4.c
index b22b2c745c76..69e331799604 100644
--- a/net/ipv4/netfilter/nf_tproxy_ipv4.c
+++ b/net/ipv4/netfilter/nf_tproxy_ipv4.c
@@ -38,7 +38,7 @@ nf_tproxy_handle_time_wait4(struct net *net, struct sk_buff *skb,
 					    hp->source, lport ? lport : hp->dest,
 					    skb->dev, NF_TPROXY_LOOKUP_LISTENER);
 		if (sk2) {
-			inet_twsk_deschedule_put(inet_twsk(sk));
+			nf_tproxy_twsk_deschedule_put(inet_twsk(sk));
 			sk = sk2;
 		}
 	}
diff --git a/net/ipv6/netfilter/nf_tproxy_ipv6.c b/net/ipv6/netfilter/nf_tproxy_ipv6.c
index 929502e51203..52f828bb5a83 100644
--- a/net/ipv6/netfilter/nf_tproxy_ipv6.c
+++ b/net/ipv6/netfilter/nf_tproxy_ipv6.c
@@ -63,7 +63,7 @@ nf_tproxy_handle_time_wait6(struct sk_buff *skb, int tproto, int thoff,
 					    lport ? lport : hp->dest,
 					    skb->dev, NF_TPROXY_LOOKUP_LISTENER);
 		if (sk2) {
-			inet_twsk_deschedule_put(inet_twsk(sk));
+			nf_tproxy_twsk_deschedule_put(inet_twsk(sk));
 			sk = sk2;
 		}
 	}
-- 
2.30.2

[PATCH net 3/3] netfilter: conntrack: adopt safer max chain length

[Pablo Neira Ayuso]

From: Eric Dumazet <edumazet@google.com>

Customers using GKE 1.25 and 1.26 are facing conntrack issues
root caused to commit c9c3b6811f74 ("netfilter: conntrack: make
max chain length random").

Even if we assume Uniform Hashing, a bucket often reachs 8 chained
items while the load factor of the hash table is smaller than 0.5

With a limit of 16, we reach load factors of 3.
With a limit of 32, we reach load factors of 11.
With a limit of 40, we reach load factors of 15.
With a limit of 50, we reach load factors of 24.

This patch changes MIN_CHAINLEN to 50, to minimize risks.

Ideally, we could in the future add a cushion based on expected
load factor (2 * nf_conntrack_max / nf_conntrack_buckets),
because some setups might expect unusual values.

Fixes: c9c3b6811f74 ("netfilter: conntrack: make max chain length random")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 7250082e7de5..c6a6a6099b4e 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -96,8 +96,8 @@ static DEFINE_MUTEX(nf_conntrack_mutex);
 #define GC_SCAN_MAX_DURATION	msecs_to_jiffies(10)
 #define GC_SCAN_EXPIRED_MAX	(64000u / HZ)
 
-#define MIN_CHAINLEN	8u
-#define MAX_CHAINLEN	(32u - MIN_CHAINLEN)
+#define MIN_CHAINLEN	50u
+#define MAX_CHAINLEN	(80u - MIN_CHAINLEN)
 
 static struct conntrack_gc_work conntrack_gc_work;
 
-- 
2.30.2

Re: [PATCH net 0/3] Netfilter fixes for net

[Paolo Abeni]

On Tue, 2023-03-07 at 11:04 +0100, Pablo Neira Ayuso wrote:
> Hi,
> 
> The following patchset contains Netfilter fixes for net:
> 
> 1) Restore ctnetlink zero mark in events and dump, from Ivan Delalande.
> 
> 2) Fix deadlock due to missing disabled bh in tproxy, from Florian Westphal.
> 
> 3) Safer maximum chain load in conntrack, from Eric Dumazet.
> 
> Please, pull these changes from:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git
> 
> Thanks.
> 
> ----------------------------------------------------------------
> 
> The following changes since commit 528125268588a18a2f257002af051b62b14bb282:
> 
>   Merge branch 'nfp-ipsec-csum' (2023-03-03 08:28:44 +0000)
> 
> are available in the Git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git HEAD

It's not clear to me the root cause, but pulling from the above ref.
yields nothing. I have to replace 'HEAD' with main to get the expected
patches.

Cheers,

Paolo

Re: [PATCH net 0/3] Netfilter fixes for net

[Jakub Kicinski]

On Tue, 07 Mar 2023 13:57:07 +0100 Paolo Abeni wrote:
> On Tue, 2023-03-07 at 11:04 +0100, Pablo Neira Ayuso wrote:
> > The following changes since commit 528125268588a18a2f257002af051b62b14bb282:
> > 
> >   Merge branch 'nfp-ipsec-csum' (2023-03-03 08:28:44 +0000)
> > 
> > are available in the Git repository at:
> > 
> >   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git HEAD  
> 
> It's not clear to me the root cause, but pulling from the above ref.
> yields nothing. I have to replace 'HEAD' with main to get the expected
> patches.

Possibly netfilter folks did not update HEAD to point to main?

ssh git@gitolite.kernel.org symbolic-ref \
    pub/scm/linux/kernel/git/netfilter/nf \
    HEAD refs/heads/main

Re: [PATCH net 0/3] Netfilter fixes for net

[Pablo Neira Ayuso]

On Tue, Mar 07, 2023 at 09:26:04AM -0800, Jakub Kicinski wrote:
> On Tue, 07 Mar 2023 13:57:07 +0100 Paolo Abeni wrote:
> > On Tue, 2023-03-07 at 11:04 +0100, Pablo Neira Ayuso wrote:
> > > The following changes since commit 528125268588a18a2f257002af051b62b14bb282:
> > > 
> > >   Merge branch 'nfp-ipsec-csum' (2023-03-03 08:28:44 +0000)
> > > 
> > > are available in the Git repository at:
> > > 
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf.git HEAD  
> > 
> > It's not clear to me the root cause, but pulling from the above ref.
> > yields nothing. I have to replace 'HEAD' with main to get the expected
> > patches.
> 
> Possibly netfilter folks did not update HEAD to point to main?
> 
> ssh git@gitolite.kernel.org symbolic-ref \
>     pub/scm/linux/kernel/git/netfilter/nf \
>     HEAD refs/heads/main

Fixed, thanks.

I will also review my pull request scripts to check if someone got
unadjusted after the switch to the main branch.