Received-SPF: pass (google.com: domain of linux-kernel+bounces-49778-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Fri, 02 Feb 2024 12:40:10 +0100
Subject: [PATCH net-next 4/5] mptcp: annotate lockless access for token
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <20240202-upstream-net-next-20240202-mptcp-annotate-lockless-access-v1-4-031d6680afdc@kernel.org>
References: <20240202-upstream-net-next-20240202-mptcp-annotate-lockless-access-v1-0-031d6680afdc@kernel.org>
In-Reply-To: <20240202-upstream-net-next-20240202-mptcp-annotate-lockless-access-v1-0-031d6680afdc@kernel.org>
To: mptcp@lists.linux.dev, Mat Martineau <martineau@kernel.org>, 
 Geliang Tang <geliang.tang@linux.dev>, 
 "David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
 Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, 
 "Matthieu Baerts (NGI0)" <matttbe@kernel.org>

From: Paolo Abeni <pabeni@redhat.com>

The token field is manipulated under the msk socket lock
and accessed lockless in a few spots, add proper ONCE annotation

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 net/mptcp/pm.c         |  2 +-
 net/mptcp/pm_netlink.c | 10 +++++-----
 net/mptcp/protocol.c   |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 4ae19113b8eb..53e0b08b1123 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -77,7 +77,7 @@ void mptcp_pm_new_connection(struct mptcp_sock *msk, const struct sock *ssk, int
 {
 	struct mptcp_pm_data *pm = &msk->pm;
 
-	pr_debug("msk=%p, token=%u side=%d", msk, msk->token, server_side);
+	pr_debug("msk=%p, token=%u side=%d", msk, READ_ONCE(msk->token), server_side);
 
 	WRITE_ONCE(pm->server_side, server_side);
 	mptcp_event(MPTCP_EVENT_CREATED, msk, ssk, GFP_ATOMIC);
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 287a60381eae..d9ad45959219 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -1997,7 +1997,7 @@ static int mptcp_event_put_token_and_ssk(struct sk_buff *skb,
 	const struct mptcp_subflow_context *sf;
 	u8 sk_err;
 
-	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)))
 		return -EMSGSIZE;
 
 	if (mptcp_event_add_subflow(skb, ssk))
@@ -2055,7 +2055,7 @@ static int mptcp_event_created(struct sk_buff *skb,
 			       const struct mptcp_sock *msk,
 			       const struct sock *ssk)
 {
-	int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token);
+	int err = nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token));
 
 	if (err)
 		return err;
@@ -2083,7 +2083,7 @@ void mptcp_event_addr_removed(const struct mptcp_sock *msk, uint8_t id)
 	if (!nlh)
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)))
 		goto nla_put_failure;
 
 	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, id))
@@ -2118,7 +2118,7 @@ void mptcp_event_addr_announced(const struct sock *ssk,
 	if (!nlh)
 		goto nla_put_failure;
 
-	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token))
+	if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)))
 		goto nla_put_failure;
 
 	if (nla_put_u8(skb, MPTCP_ATTR_REM_ID, info->id))
@@ -2234,7 +2234,7 @@ void mptcp_event(enum mptcp_event_type type, const struct mptcp_sock *msk,
 			goto nla_put_failure;
 		break;
 	case MPTCP_EVENT_CLOSED:
-		if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, msk->token) < 0)
+		if (nla_put_u32(skb, MPTCP_ATTR_TOKEN, READ_ONCE(msk->token)) < 0)
 			goto nla_put_failure;
 		break;
 	case MPTCP_EVENT_ANNOUNCED:
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 90804e7fb7f6..4478ddd3b5fa 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3199,7 +3199,7 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 
 	msk = mptcp_sk(nsk);
 	WRITE_ONCE(msk->local_key, subflow_req->local_key);
-	msk->token = subflow_req->token;
+	WRITE_ONCE(msk->token, subflow_req->token);
 	msk->in_accept_queue = 1;
 	WRITE_ONCE(msk->fully_established, false);
 	if (mp_opt->suboptions & OPTION_MPTCP_CSUMREQD)

-- 
2.43.0