From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 23FB41FB9 for ; Fri, 3 Feb 2023 10:15:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79F07C4339B; Fri, 3 Feb 2023 10:15:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1675419345; bh=7UwvYFByB20saoVSvH1j/CggmuIiRUMJjLAS0+X/jfQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dLRAEV621Sl/OwxldWKHzV+7Wsr1XrmJN/VtwZrAe8JngGSZP8pzNKB9RQP9P5cMb 5WVV+lohTJV4M51XpuGILhRVsOLgbom3VwDmprXEbAucGFEVgWDQ29CqtJo1RpgRpS MDpZhJWbcWYOYprWUIVNvourL8dbf0a4/hEvmyTg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.14 30/62] netlink: annotate data races around dst_portid and dst_group Date: Fri, 3 Feb 2023 11:12:26 +0100 Message-Id: <20230203101014.311613084@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230203101012.959398849@linuxfoundation.org> References: <20230203101012.959398849@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Dumazet [ Upstream commit 004db64d185a5f23dfb891d7701e23713b2420ee ] netlink_getname(), netlink_sendmsg() and netlink_getsockbyportid() can read nlk->dst_portid and nlk->dst_group while another thread is changing them. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/netlink/af_netlink.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 1b2e99ce54e5..1547d0825668 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1062,8 +1062,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, if (addr->sa_family == AF_UNSPEC) { sk->sk_state = NETLINK_UNCONNECTED; - nlk->dst_portid = 0; - nlk->dst_group = 0; + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, 0); + WRITE_ONCE(nlk->dst_group, 0); return 0; } if (addr->sa_family != AF_NETLINK) @@ -1085,8 +1086,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, if (err == 0) { sk->sk_state = NETLINK_CONNECTED; - nlk->dst_portid = nladdr->nl_pid; - nlk->dst_group = ffs(nladdr->nl_groups); + /* dst_portid and dst_group can be read locklessly */ + WRITE_ONCE(nlk->dst_portid, nladdr->nl_pid); + WRITE_ONCE(nlk->dst_group, ffs(nladdr->nl_groups)); } return err; @@ -1104,8 +1106,9 @@ static int netlink_getname(struct socket *sock, struct sockaddr *addr, *addr_len = sizeof(*nladdr); if (peer) { - nladdr->nl_pid = nlk->dst_portid; - nladdr->nl_groups = netlink_group_mask(nlk->dst_group); + /* Paired with WRITE_ONCE() in netlink_connect() */ + nladdr->nl_pid = READ_ONCE(nlk->dst_portid); + nladdr->nl_groups = netlink_group_mask(READ_ONCE(nlk->dst_group)); } else { nladdr->nl_pid = nlk->portid; netlink_lock_table(); @@ -1134,8 +1137,9 @@ static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid) /* Don't bother queuing skb if kernel socket has no input function */ nlk = nlk_sk(sock); + /* dst_portid can be changed in netlink_connect() */ if (sock->sk_state == NETLINK_CONNECTED && - nlk->dst_portid != nlk_sk(ssk)->portid) { + READ_ONCE(nlk->dst_portid) != nlk_sk(ssk)->portid) { sock_put(sock); return ERR_PTR(-ECONNREFUSED); } @@ -1847,8 +1851,9 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) goto out; netlink_skb_flags |= NETLINK_SKB_DST; } else { - dst_portid = nlk->dst_portid; - dst_group = nlk->dst_group; + /* Paired with WRITE_ONCE() in netlink_connect() */ + dst_portid = READ_ONCE(nlk->dst_portid); + dst_group = READ_ONCE(nlk->dst_group); } /* Paired with WRITE_ONCE() in netlink_insert() */ -- 2.39.0