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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 87263C43612 for ; Tue, 15 Jan 2019 17:00:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58AF120859 for ; Tue, 15 Jan 2019 17:00:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547571602; bh=WeCkk4n1fVMDf8UFp0B6h5kL+b+aJenhZUHz0i+xZGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FRSd184HWMyF4X7cm6TzN6baFOSOGZJ/n5PBXgByDM5OjwmjTBfK3fvPW4gnyIasL tRnNDBARfS0h2yDnqGvvKL6PFeXvYNvV8xoyUeM06OdtSXWOCMlhBAosZ8QFsOwm6L W/F/Cw8g+aCWZWDc+mg/K9CMJr4MHlszmedif1tQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727618AbfAOQiv (ORCPT ); Tue, 15 Jan 2019 11:38:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:54876 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728745AbfAOQiu (ORCPT ); Tue, 15 Jan 2019 11:38:50 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 48D0620859; Tue, 15 Jan 2019 16:38:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1547570329; bh=WeCkk4n1fVMDf8UFp0B6h5kL+b+aJenhZUHz0i+xZGQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GWanbG9PVR3SRyT9ajILHEOr4aDidI44G63EUSWzfGRBEeUIujwUd/yi/4mURx0eG YTmT36O9csgOws/6uDOmFWzT6Sacdxzm0pAMvHdLnzeWIL454TsvK/dEQquoAKa/kt M0HA+S+D2oLP/EC3ypUrDXVDuRUSJBUUAozcn05I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vasily Averin , "J. Bruce Fields" Subject: [PATCH 4.4 51/51] sunrpc: use-after-free in svc_process_common() Date: Tue, 15 Jan 2019 17:35:47 +0100 Message-Id: <20190115154854.340253552@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190115154846.928796000@linuxfoundation.org> References: <20190115154846.928796000@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vasily Averin commit d4b09acf924b84bae77cad090a9d108e70b43643 upstream. if node have NFSv41+ mounts inside several net namespaces it can lead to use-after-free in svc_process_common() svc_process_common() /* Setup reply header */ rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); <<< HERE svc_process_common() can use incorrect rqstp->rq_xprt, its caller function bc_svc_process() takes it from serv->sv_bc_xprt. The problem is that serv is global structure but sv_bc_xprt is assigned per-netnamespace. According to Trond, the whole "let's set up rqstp->rq_xprt for the back channel" is nothing but a giant hack in order to work around the fact that svc_process_common() uses it to find the xpt_ops, and perform a couple of (meaningless for the back channel) tests of xpt_flags. All we really need in svc_process_common() is to be able to run rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr() Bruce J Fields points that this xpo_prep_reply_hdr() call is an awfully roundabout way just to do "svc_putnl(resv, 0);" in the tcp case. This patch does not initialiuze rqstp->rq_xprt in bc_svc_process(), now it calls svc_process_common() with rqstp->rq_xprt = NULL. To adjust reply header svc_process_common() just check rqstp->rq_prot and calls svc_tcp_prep_reply_hdr() for tcp case. To handle rqstp->rq_xprt = NULL case in functions called from svc_process_common() patch intruduces net namespace pointer svc_rqst->rq_bc_net and adjust SVC_NET() definition. Some other function was also adopted to properly handle described case. Signed-off-by: Vasily Averin Cc: stable@vger.kernel.org Fixes: 23c20ecd4475 ("NFS: callback up - users counting cleanup") Signed-off-by: J. Bruce Fields v2: - added lost extern svc_tcp_prep_reply_hdr() - dropped trace_svc_process() changes - context fixes in svc_process_common() Signed-off-by: Vasily Averin Signed-off-by: Greg Kroah-Hartman --- include/linux/sunrpc/svc.h | 5 ++++- net/sunrpc/svc.c | 10 +++++++--- net/sunrpc/svc_xprt.c | 5 +++-- net/sunrpc/svcsock.c | 2 +- 4 files changed, 15 insertions(+), 7 deletions(-) --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -290,9 +290,12 @@ struct svc_rqst { struct svc_cacherep * rq_cacherep; /* cache info */ struct task_struct *rq_task; /* service thread */ spinlock_t rq_lock; /* per-request lock */ + struct net *rq_bc_net; /* pointer to backchannel's + * net namespace + */ }; -#define SVC_NET(svc_rqst) (svc_rqst->rq_xprt->xpt_net) +#define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net) /* * Rigorous type checking on sockaddr type conversions --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1062,6 +1062,8 @@ void svc_printk(struct svc_rqst *rqstp, static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {} #endif +extern void svc_tcp_prep_reply_hdr(struct svc_rqst *); + /* * Common routine for processing the RPC request. */ @@ -1091,7 +1093,8 @@ svc_process_common(struct svc_rqst *rqst clear_bit(RQ_DROPME, &rqstp->rq_flags); /* Setup reply header */ - rqstp->rq_xprt->xpt_ops->xpo_prep_reply_hdr(rqstp); + if (rqstp->rq_prot == IPPROTO_TCP) + svc_tcp_prep_reply_hdr(rqstp); svc_putu32(resv, rqstp->rq_xid); @@ -1138,7 +1141,8 @@ svc_process_common(struct svc_rqst *rqst case SVC_DENIED: goto err_bad_auth; case SVC_CLOSE: - if (test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) + if (rqstp->rq_xprt && + test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags)) svc_close_xprt(rqstp->rq_xprt); case SVC_DROP: goto dropit; @@ -1360,10 +1364,10 @@ bc_svc_process(struct svc_serv *serv, st dprintk("svc: %s(%p)\n", __func__, req); /* Build the svc_rqst used by the common processing routine */ - rqstp->rq_xprt = serv->sv_bc_xprt; rqstp->rq_xid = req->rq_xid; rqstp->rq_prot = req->rq_xprt->prot; rqstp->rq_server = serv; + rqstp->rq_bc_net = req->rq_xprt->xprt_net; rqstp->rq_addrlen = sizeof(req->rq_xprt->addr); memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen); --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -454,10 +454,11 @@ out: */ void svc_reserve(struct svc_rqst *rqstp, int space) { + struct svc_xprt *xprt = rqstp->rq_xprt; + space += rqstp->rq_res.head[0].iov_len; - if (space < rqstp->rq_reserved) { - struct svc_xprt *xprt = rqstp->rq_xprt; + if (xprt && space < rqstp->rq_reserved) { atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved); rqstp->rq_reserved = space; --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1240,7 +1240,7 @@ static int svc_tcp_sendto(struct svc_rqs /* * Setup response header. TCP has a 4B record length field. */ -static void svc_tcp_prep_reply_hdr(struct svc_rqst *rqstp) +void svc_tcp_prep_reply_hdr(struct svc_rqst *rqstp) { struct kvec *resv = &rqstp->rq_res.head[0];