From: Florian Westphal <fw@strlen.de>
Date: Fri, 3 Mar 2023 10:58:56 +0100
Subject: [PATCH] netfilter: tproxy: fix deadlock due to missing BH disable
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References: bsc#1012628
Patch-mainline: 6.2.7
Git-commit: 4a02426787bf024dafdb79b362285ee325de3f5e
[ Upstream commit 4a02426787bf024dafdb79b362285ee325de3f5e ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 82d0e41b..faa108b1 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 b22b2c74..69e33179 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 929502e5..52f828bb 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;
}
}
--
2.35.3