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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 31E49C65BAF for ; Sun, 9 Dec 2018 21:57:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0022420661 for ; Sun, 9 Dec 2018 21:57:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0022420661 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727000AbeLIV5E (ORCPT ); Sun, 9 Dec 2018 16:57:04 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36462 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726823AbeLIVzo (ORCPT ); Sun, 9 Dec 2018 16:55:44 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW738-0002po-6G; Sun, 09 Dec 2018 21:55:42 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72f-0003Te-Mf; Sun, 09 Dec 2018 21:55:13 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jason Gunthorpe" , "Jann Horn" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 191/328] RDMA/ucma: check fd type in ucma_migrate_id() In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit 0d23ba6034b9cf48b8918404367506da3e4b3ee5 upstream. The current code grabs the private_data of whatever file descriptor userspace has supplied and implicitly casts it to a `struct ucma_file *`, potentially causing a type confusion. This is probably fine in practice because the pointer is only used for comparisons, it is never actually dereferenced; and even in the comparisons, it is unlikely that a file from another filesystem would have a ->private_data pointer that happens to also be valid in this context. But ->private_data is not always guaranteed to be a valid pointer to an object owned by the file's filesystem; for example, some filesystems just cram numbers in there. Check the type of the supplied file descriptor to be safe, analogous to how other places in the kernel do it. Fixes: 88314e4dda1e ("RDMA/cma: add support for rdma_migrate_id()") Signed-off-by: Jann Horn Signed-off-by: Jason Gunthorpe Signed-off-by: Ben Hutchings --- drivers/infiniband/core/ucma.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -113,6 +113,8 @@ static DEFINE_MUTEX(mut); static DEFINE_IDR(ctx_idr); static DEFINE_IDR(multicast_idr); +static const struct file_operations ucma_fops; + static inline struct ucma_context *_ucma_find_context(int id, struct ucma_file *file) { @@ -1448,6 +1450,10 @@ static ssize_t ucma_migrate_id(struct uc f = fdget(cmd.fd); if (!f.file) return -ENOENT; + if (f.file->f_op != &ucma_fops) { + ret = -EINVAL; + goto file_put; + } /* Validate current fd and prevent destruction of id. */ ctx = ucma_get_ctx(f.file->private_data, cmd.id);