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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DCF0C43215 for ; Sat, 16 Nov 2019 16:04:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 363E0206C0 for ; Sat, 16 Nov 2019 16:04:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573920245; bh=AV/zQ3grI4g6c2Q6sjeaJCpxGDoltA1NpCB4s6lo8/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=e9nFv9y/N2ObvBfQ6pVddLeHUTtl2V7WLqf6SQB7hdPEqkui9pEpc5bRVI4mLNFnN cL2vAzbK4QJdUvrZ9MXR+gtACxNenmBseTef7/vMHdMd+epNj9qJ0/QwXgts1otYvs 1JdddBkYiljpZw9kiWQ9Ow4U+dPYkCK9iE/FTndQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730856AbfKPPvx (ORCPT ); Sat, 16 Nov 2019 10:51:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:60682 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730848AbfKPPvx (ORCPT ); Sat, 16 Nov 2019 10:51:53 -0500 Received: from sasha-vm.mshome.net (unknown [50.234.116.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D89CE20859; Sat, 16 Nov 2019 15:51:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573919512; bh=AV/zQ3grI4g6c2Q6sjeaJCpxGDoltA1NpCB4s6lo8/0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b4yIvZnbYaQquROQWgvPxWIXsSZ4PLahV7uz4mK+b5RMvB7fUE9jrDtOI0sOhkb0R lSvOZT3tDiqWMPn3KiyPU51S/bupN+jx2SkF8TnnBXtzpl2rIopudrXIg8eLd9reSe kCi0uCLp5S3GjyU0lytnk5ffh87oWWdj8IftqQXk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "J. Bruce Fields" , Trond Myklebust , Sasha Levin , linux-nfs@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 34/99] sunrpc: safely reallow resvport min/max inversion Date: Sat, 16 Nov 2019 10:49:57 -0500 Message-Id: <20191116155103.10971-34-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191116155103.10971-1-sashal@kernel.org> References: <20191116155103.10971-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: "J. Bruce Fields" [ Upstream commit 826799e66e8683e5698e140bb9ef69afc8c0014e ] Commits ffb6ca33b04b and e08ea3a96fc7 prevent setting xprt_min_resvport greater than xprt_max_resvport, but may also break simple code that sets one parameter then the other, if the new range does not overlap the old. Also it looks racy to me, unless there's some serialization I'm not seeing. Granted it would probably require malicious privileged processes (unless there's a chance these might eventually be settable in unprivileged containers), but still it seems better not to let userspace panic the kernel. Simpler seems to be to allow setting the parameters to whatever you want but interpret xprt_min_resvport > xprt_max_resvport as the empty range. Fixes: ffb6ca33b04b "sunrpc: Prevent resvport min/max inversion..." Fixes: e08ea3a96fc7 "sunrpc: Prevent rexvport min/max inversion..." Signed-off-by: J. Bruce Fields Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin --- net/sunrpc/xprtsock.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 280fb31787084..f3f05148922a1 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -124,7 +124,7 @@ static struct ctl_table xs_tunables_table[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = &xprt_min_resvport_limit, - .extra2 = &xprt_max_resvport + .extra2 = &xprt_max_resvport_limit }, { .procname = "max_resvport", @@ -132,7 +132,7 @@ static struct ctl_table xs_tunables_table[] = { .maxlen = sizeof(unsigned int), .mode = 0644, .proc_handler = proc_dointvec_minmax, - .extra1 = &xprt_min_resvport, + .extra1 = &xprt_min_resvport_limit, .extra2 = &xprt_max_resvport_limit }, { @@ -1737,11 +1737,17 @@ static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task) xprt_adjust_cwnd(xprt, task, -ETIMEDOUT); } -static unsigned short xs_get_random_port(void) +static int xs_get_random_port(void) { - unsigned short range = xprt_max_resvport - xprt_min_resvport + 1; - unsigned short rand = (unsigned short) prandom_u32() % range; - return rand + xprt_min_resvport; + unsigned short min = xprt_min_resvport, max = xprt_max_resvport; + unsigned short range; + unsigned short rand; + + if (max < min) + return -EADDRINUSE; + range = max - min + 1; + rand = (unsigned short) prandom_u32() % range; + return rand + min; } /** @@ -1798,9 +1804,9 @@ static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock) transport->srcport = xs_sock_getport(sock); } -static unsigned short xs_get_srcport(struct sock_xprt *transport) +static int xs_get_srcport(struct sock_xprt *transport) { - unsigned short port = transport->srcport; + int port = transport->srcport; if (port == 0 && transport->xprt.resvport) port = xs_get_random_port(); @@ -1821,7 +1827,7 @@ static int xs_bind(struct sock_xprt *transport, struct socket *sock) { struct sockaddr_storage myaddr; int err, nloop = 0; - unsigned short port = xs_get_srcport(transport); + int port = xs_get_srcport(transport); unsigned short last; /* @@ -1839,8 +1845,8 @@ static int xs_bind(struct sock_xprt *transport, struct socket *sock) * transport->xprt.resvport == 1) xs_get_srcport above will * ensure that port is non-zero and we will bind as needed. */ - if (port == 0) - return 0; + if (port <= 0) + return port; memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen); do { @@ -3223,12 +3229,8 @@ static int param_set_uint_minmax(const char *val, static int param_set_portnr(const char *val, const struct kernel_param *kp) { - if (kp->arg == &xprt_min_resvport) - return param_set_uint_minmax(val, kp, - RPC_MIN_RESVPORT, - xprt_max_resvport); return param_set_uint_minmax(val, kp, - xprt_min_resvport, + RPC_MIN_RESVPORT, RPC_MAX_RESVPORT); } -- 2.20.1