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Message-ID: <20240128103732.18185-2-kuniyu@amazon.com>
Date: Sun, 28 Jan 2024 02:37:31 -0800
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>
CC: Kent Overstreet <kent.overstreet@...ux.dev>, Kuniyuki Iwashima
<kuniyu@...zon.com>, Kuniyuki Iwashima <kuni1840@...il.com>,
<netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 1/2] af_unix: Set sk_peer_pid/sk_peer_cred locklessly for new socket.
init_peercred() is called in 3 places:
1. socketpair() : both sockets
2. connect() : child socket
3. listen() : listening socket
The first two need not hold sk_peer_lock because no one can
touch the socket.
Let's set cred/pid without holding lock for the two cases and
rename the old init_peercred() to update_peercred() to properly
reflect the use case.
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
net/unix/af_unix.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 1720419d93d6..f07374d31f7c 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -684,6 +684,12 @@ static void unix_release_sock(struct sock *sk, int embrion)
}
static void init_peercred(struct sock *sk)
+{
+ sk->sk_peer_pid = get_pid(task_tgid(current));
+ sk->sk_peer_cred = get_current_cred();
+}
+
+static void update_peercred(struct sock *sk)
{
const struct cred *old_cred;
struct pid *old_pid;
@@ -691,8 +697,7 @@ static void init_peercred(struct sock *sk)
spin_lock(&sk->sk_peer_lock);
old_pid = sk->sk_peer_pid;
old_cred = sk->sk_peer_cred;
- sk->sk_peer_pid = get_pid(task_tgid(current));
- sk->sk_peer_cred = get_current_cred();
+ init_peercred(sk);
spin_unlock(&sk->sk_peer_lock);
put_pid(old_pid);
@@ -743,7 +748,7 @@ static int unix_listen(struct socket *sock, int backlog)
sk->sk_max_ack_backlog = backlog;
sk->sk_state = TCP_LISTEN;
/* set credentials so connect can copy them */
- init_peercred(sk);
+ update_peercred(sk);
err = 0;
out_unlock:
--
2.30.2
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