From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 13 Sep 2021 08:43:04 +0000 (+0200)
Subject: 5.4-stable patches
X-Git-Tag: v5.4.146~37
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=296532650d308bdc18c5abcbcd6175b060b3a248;p=thirdparty%2Fkernel%2Fstable-queue.git

5.4-stable patches

added patches:
	netns-protect-netns-id-lookups-with-rcu.patch
---

diff --git a/queue-5.4/netns-protect-netns-id-lookups-with-rcu.patch b/queue-5.4/netns-protect-netns-id-lookups-with-rcu.patch
new file mode 100644
index 00000000000..ba36b0d3652
--- /dev/null
+++ b/queue-5.4/netns-protect-netns-id-lookups-with-rcu.patch
@@ -0,0 +1,94 @@
+From 2dce224f469f060b9998a5a869151ef83c08ce77 Mon Sep 17 00:00:00 2001
+From: Guillaume Nault <gnault@redhat.com>
+Date: Mon, 13 Jan 2020 22:39:22 +0100
+Subject: netns: protect netns ID lookups with RCU
+
+From: Guillaume Nault <gnault@redhat.com>
+
+commit 2dce224f469f060b9998a5a869151ef83c08ce77 upstream.
+
+__peernet2id() can be protected by RCU as it only calls idr_for_each(),
+which is RCU-safe, and never modifies the nsid table.
+
+rtnl_net_dumpid() can also do lockless lookups. It does two nested
+idr_for_each() calls on nsid tables (one direct call and one indirect
+call because of rtnl_net_dumpid_one() calling __peernet2id()). The
+netnsid tables are never updated. Therefore it is safe to not take the
+nsid_lock and run within an RCU-critical section instead.
+
+Signed-off-by: Guillaume Nault <gnault@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Signed-off-by: HÃ¥kon Bugge <haakon.bugge@oracle.com>
+
+---
+ net/core/net_namespace.c |   28 ++++++++++------------------
+ 1 file changed, 10 insertions(+), 18 deletions(-)
+
+--- a/net/core/net_namespace.c
++++ b/net/core/net_namespace.c
+@@ -211,9 +211,9 @@ static int net_eq_idr(int id, void *net,
+ 	return 0;
+ }
+ 
+-/* Should be called with nsid_lock held. If a new id is assigned, the bool alloc
+- * is set to true, thus the caller knows that the new id must be notified via
+- * rtnl.
++/* Must be called from RCU-critical section or with nsid_lock held. If
++ * a new id is assigned, the bool alloc is set to true, thus the
++ * caller knows that the new id must be notified via rtnl.
+  */
+ static int __peernet2id_alloc(struct net *net, struct net *peer, bool *alloc)
+ {
+@@ -237,7 +237,7 @@ static int __peernet2id_alloc(struct net
+ 	return NETNSA_NSID_NOT_ASSIGNED;
+ }
+ 
+-/* should be called with nsid_lock held */
++/* Must be called from RCU-critical section or with nsid_lock held */
+ static int __peernet2id(struct net *net, struct net *peer)
+ {
+ 	bool no = false;
+@@ -281,9 +281,10 @@ int peernet2id(struct net *net, struct n
+ {
+ 	int id;
+ 
+-	spin_lock_bh(&net->nsid_lock);
++	rcu_read_lock();
+ 	id = __peernet2id(net, peer);
+-	spin_unlock_bh(&net->nsid_lock);
++	rcu_read_unlock();
++
+ 	return id;
+ }
+ EXPORT_SYMBOL(peernet2id);
+@@ -962,6 +963,7 @@ struct rtnl_net_dump_cb {
+ 	int s_idx;
+ };
+ 
++/* Runs in RCU-critical section. */
+ static int rtnl_net_dumpid_one(int id, void *peer, void *data)
+ {
+ 	struct rtnl_net_dump_cb *net_cb = (struct rtnl_net_dump_cb *)data;
+@@ -1046,19 +1048,9 @@ static int rtnl_net_dumpid(struct sk_buf
+ 			goto end;
+ 	}
+ 
+-	spin_lock_bh(&net_cb.tgt_net->nsid_lock);
+-	if (net_cb.fillargs.add_ref &&
+-	    !net_eq(net_cb.ref_net, net_cb.tgt_net) &&
+-	    !spin_trylock_bh(&net_cb.ref_net->nsid_lock)) {
+-		spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
+-		err = -EAGAIN;
+-		goto end;
+-	}
++	rcu_read_lock();
+ 	idr_for_each(&net_cb.tgt_net->netns_ids, rtnl_net_dumpid_one, &net_cb);
+-	if (net_cb.fillargs.add_ref &&
+-	    !net_eq(net_cb.ref_net, net_cb.tgt_net))
+-		spin_unlock_bh(&net_cb.ref_net->nsid_lock);
+-	spin_unlock_bh(&net_cb.tgt_net->nsid_lock);
++	rcu_read_unlock();
+ 
+ 	cb->args[0] = net_cb.idx;
+ end:
diff --git a/queue-5.4/series b/queue-5.4/series
index a8ca7a6ba28..21f681fa20c 100644
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -59,6 +59,7 @@ media-go7007-remove-redundant-initialization.patch
 media-coda-fix-frame_mem_ctrl-for-yuv420-and-yvu420-.patch
 bluetooth-sco-prevent-information-leak-in-sco_conn_d.patch
 6lowpan-iphc-fix-an-off-by-one-check-of-array-index.patch
+netns-protect-netns-id-lookups-with-rcu.patch
 drm-amdgpu-acp-make-pm-domain-really-work.patch
 tcp-seq_file-avoid-skipping-sk-during-tcp_seek_last_.patch
 arm-dts-meson8-use-a-higher-default-gpu-clock-freque.patch