From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97D37C433F5 for ; Mon, 14 Feb 2022 10:33:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347992AbiBNKdN (ORCPT ); Mon, 14 Feb 2022 05:33:13 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:41908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348031AbiBNKbu (ORCPT ); Mon, 14 Feb 2022 05:31:50 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11FFB2AD7; Mon, 14 Feb 2022 02:00:14 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 53C35B80DCE; Mon, 14 Feb 2022 10:00:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76B90C340E9; Mon, 14 Feb 2022 10:00:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644832810; bh=0cCVy52/8FGsLChq8XKfbof1AzX4yIpQTcxqagmp5gg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FUyzuvQ+0eW+mJk48ytz6oURLkMUe46SQ5Nht+LFGOv/jDPkauu0tHnzT/PkGMvcx vUf3xq1u2V6iB/OhXBS4ZACDR/gyWF4od2sHX+V6kSQmM1R9JBo3SJfI7TfAE9d31o 4+LFDEkexx5FQw9Q79T6HuxbbENOzjtj0ukiFAHU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, NeilBrown , Anna Schumaker , Sasha Levin Subject: [PATCH 5.16 131/203] SUNRPC: lock against ->sock changing during sysfs read Date: Mon, 14 Feb 2022 10:26:15 +0100 Message-Id: <20220214092514.683072285@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220214092510.221474733@linuxfoundation.org> References: <20220214092510.221474733@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: NeilBrown [ Upstream commit b49ea673e119f59c71645e2f65b3ccad857c90ee ] ->sock can be set to NULL asynchronously unless ->recv_mutex is held. So it is important to hold that mutex. Otherwise a sysfs read can trigger an oops. Commit 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads") appears to attempt to fix this problem, but it only narrows the race window. Fixes: 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads") Fixes: a8482488a7d6 ("SUNRPC query transport's source port") Signed-off-by: NeilBrown Signed-off-by: Anna Schumaker Signed-off-by: Sasha Levin --- net/sunrpc/sysfs.c | 5 ++++- net/sunrpc/xprtsock.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/sysfs.c b/net/sunrpc/sysfs.c index 8f309bcdf84fe..0c28280dd3bcb 100644 --- a/net/sunrpc/sysfs.c +++ b/net/sunrpc/sysfs.c @@ -115,11 +115,14 @@ static ssize_t rpc_sysfs_xprt_srcaddr_show(struct kobject *kobj, } sock = container_of(xprt, struct sock_xprt, xprt); - if (kernel_getsockname(sock->sock, (struct sockaddr *)&saddr) < 0) + mutex_lock(&sock->recv_mutex); + if (sock->sock == NULL || + kernel_getsockname(sock->sock, (struct sockaddr *)&saddr) < 0) goto out; ret = sprintf(buf, "%pISc\n", &saddr); out: + mutex_unlock(&sock->recv_mutex); xprt_put(xprt); return ret + 1; } diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index d8ee06a9650a1..03770e56df361 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1641,7 +1641,12 @@ static int xs_get_srcport(struct sock_xprt *transport) unsigned short get_srcport(struct rpc_xprt *xprt) { struct sock_xprt *sock = container_of(xprt, struct sock_xprt, xprt); - return xs_sock_getport(sock->sock); + unsigned short ret = 0; + mutex_lock(&sock->recv_mutex); + if (sock->sock) + ret = xs_sock_getport(sock->sock); + mutex_unlock(&sock->recv_mutex); + return ret; } EXPORT_SYMBOL(get_srcport); -- 2.34.1