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Message-Id: <20210924220507.24543-2-xiyou.wangcong@gmail.com>
Date: Fri, 24 Sep 2021 15:05:05 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org, Cong Wang <cong.wang@...edance.com>,
John Fastabend <john.fastabend@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
Jakub Sitnicki <jakub@...udflare.com>,
Lorenz Bauer <lmb@...udflare.com>
Subject: [Patch bpf 1/3] skmsg: introduce sk_psock_get_checked()
From: Cong Wang <cong.wang@...edance.com>
Although we have sk_psock_get(), it assumes the psock
retrieved from sk_user_data is for sockmap, this is not
sufficient if we call it outside of sockmap, for example,
reuseport_array.
Fortunately sock_map_psock_get_checked() is more strict
and checks for sock_map_close before using psock. So we can
refactor it and rename it to sk_psock_get_checked(), which
can be safely called outside of sockmap.
Cc: John Fastabend <john.fastabend@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Jakub Sitnicki <jakub@...udflare.com>
Cc: Lorenz Bauer <lmb@...udflare.com>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
include/linux/skmsg.h | 20 ++++++++++++++++++++
net/core/sock_map.c | 22 +---------------------
2 files changed, 21 insertions(+), 21 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14ab0c0bc924..d47097f2c8c0 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -452,6 +452,26 @@ static inline struct sk_psock *sk_psock_get(struct sock *sk)
return psock;
}
+static inline struct sk_psock *sk_psock_get_checked(struct sock *sk)
+{
+ struct sk_psock *psock;
+
+ rcu_read_lock();
+ psock = sk_psock(sk);
+ if (psock) {
+ if (sk->sk_prot->close != sock_map_close) {
+ psock = ERR_PTR(-EBUSY);
+ goto out;
+ }
+
+ if (!refcount_inc_not_zero(&psock->refcnt))
+ psock = ERR_PTR(-EBUSY);
+ }
+out:
+ rcu_read_unlock();
+ return psock;
+}
+
void sk_psock_drop(struct sock *sk, struct sk_psock *psock);
static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index e252b8ec2b85..6612bb0b95b5 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -191,26 +191,6 @@ static int sock_map_init_proto(struct sock *sk, struct sk_psock *psock)
return sk->sk_prot->psock_update_sk_prot(sk, psock, false);
}
-static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
-{
- struct sk_psock *psock;
-
- rcu_read_lock();
- psock = sk_psock(sk);
- if (psock) {
- if (sk->sk_prot->close != sock_map_close) {
- psock = ERR_PTR(-EBUSY);
- goto out;
- }
-
- if (!refcount_inc_not_zero(&psock->refcnt))
- psock = ERR_PTR(-EBUSY);
- }
-out:
- rcu_read_unlock();
- return psock;
-}
-
static int sock_map_link(struct bpf_map *map, struct sock *sk)
{
struct sk_psock_progs *progs = sock_map_progs(map);
@@ -255,7 +235,7 @@ static int sock_map_link(struct bpf_map *map, struct sock *sk)
}
}
- psock = sock_map_psock_get_checked(sk);
+ psock = sk_psock_get_checked(sk);
if (IS_ERR(psock)) {
ret = PTR_ERR(psock);
goto out_progs;
--
2.30.2
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