114 lines
4.0 KiB
Diff
114 lines
4.0 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Cong Wang <xiyou.wangcong@gmail.com>
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Date: Tue, 16 Jun 2020 11:03:52 -0700
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Subject: [PATCH] cgroup: fix cgroup_sk_alloc() for sk_clone_lock()
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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When we clone a socket in sk_clone_lock(), its sk_cgrp_data is
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copied, so the cgroup refcnt must be taken too. And, unlike the
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sk_alloc() path, sock_update_netprioidx() is not called here.
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Therefore, it is safe and necessary to grab the cgroup refcnt
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even when cgroup_sk_alloc is disabled.
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sk_clone_lock() is in BH context anyway, the in_interrupt()
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would terminate this function if called there. And for sk_alloc()
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skcd->val is always zero. So it's safe to factor out the code
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to make it more readable.
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Fixes: 090e28b229af92dc5b ("netprio_cgroup: Fix unlimited memory leak of v2 cgroups")
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Reported-by: Cameron Berkenpas <cam@neo-zeon.de>
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Reported-by: Peter Geis <pgwipeout@gmail.com>
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Reported-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
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Reported-by: Daniël Sonck <dsonck92@gmail.com>
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Tested-by: Cameron Berkenpas <cam@neo-zeon.de>
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Cc: Daniel Borkmann <daniel@iogearbox.net>
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Cc: Zefan Li <lizefan@huawei.com>
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Cc: Tejun Heo <tj@kernel.org>
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Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
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Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
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---
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include/linux/cgroup.h | 2 ++
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kernel/cgroup/cgroup.c | 26 ++++++++++++++------------
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net/core/sock.c | 2 +-
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3 files changed, 17 insertions(+), 13 deletions(-)
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diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
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index 57577075d204..14452a801d95 100644
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--- a/include/linux/cgroup.h
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+++ b/include/linux/cgroup.h
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@@ -822,6 +822,7 @@ extern spinlock_t cgroup_sk_update_lock;
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void cgroup_sk_alloc_disable(void);
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void cgroup_sk_alloc(struct sock_cgroup_data *skcd);
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+void cgroup_sk_clone(struct sock_cgroup_data *skcd);
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void cgroup_sk_free(struct sock_cgroup_data *skcd);
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static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
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@@ -847,6 +848,7 @@ static inline struct cgroup *sock_cgroup_ptr(struct sock_cgroup_data *skcd)
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#else /* CONFIG_CGROUP_DATA */
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static inline void cgroup_sk_alloc(struct sock_cgroup_data *skcd) {}
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+static inline void cgroup_sk_clone(struct sock_cgroup_data *skcd) {}
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static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
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#endif /* CONFIG_CGROUP_DATA */
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diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
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index 7c9e97553a00..d56ee72f4a07 100644
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--- a/kernel/cgroup/cgroup.c
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+++ b/kernel/cgroup/cgroup.c
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@@ -6382,18 +6382,6 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
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if (cgroup_sk_alloc_disabled)
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return;
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- /* Socket clone path */
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- if (skcd->val) {
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- /*
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- * We might be cloning a socket which is left in an empty
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- * cgroup and the cgroup might have already been rmdir'd.
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- * Don't use cgroup_get_live().
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- */
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- cgroup_get(sock_cgroup_ptr(skcd));
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- cgroup_bpf_get(sock_cgroup_ptr(skcd));
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- return;
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- }
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-
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/* Don't associate the sock with unrelated interrupted task's cgroup. */
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if (in_interrupt())
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return;
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@@ -6415,6 +6403,20 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
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rcu_read_unlock();
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}
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+void cgroup_sk_clone(struct sock_cgroup_data *skcd)
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+{
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+ /* Socket clone path */
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+ if (skcd->val) {
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+ /*
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+ * We might be cloning a socket which is left in an empty
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+ * cgroup and the cgroup might have already been rmdir'd.
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+ * Don't use cgroup_get_live().
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+ */
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+ cgroup_get(sock_cgroup_ptr(skcd));
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+ cgroup_bpf_get(sock_cgroup_ptr(skcd));
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+ }
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+}
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+
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void cgroup_sk_free(struct sock_cgroup_data *skcd)
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{
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struct cgroup *cgrp = sock_cgroup_ptr(skcd);
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diff --git a/net/core/sock.c b/net/core/sock.c
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index 0adf7a9e5a90..6ef468767ab0 100644
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--- a/net/core/sock.c
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+++ b/net/core/sock.c
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@@ -1836,7 +1836,7 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority)
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/* sk->sk_memcg will be populated at accept() time */
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newsk->sk_memcg = NULL;
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- cgroup_sk_alloc(&newsk->sk_cgrp_data);
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+ cgroup_sk_clone(&newsk->sk_cgrp_data);
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rcu_read_lock();
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filter = rcu_dereference(sk->sk_filter);
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