From patchwork Tue Jul 23 17:58:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11054961 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 799B014DB for ; Tue, 23 Jul 2019 18:00:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6AB9C20602 for ; Tue, 23 Jul 2019 18:00:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5E7B3212DB; Tue, 23 Jul 2019 18:00:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 05A0526CF9 for ; Tue, 23 Jul 2019 18:00:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391323AbfGWR7c (ORCPT ); Tue, 23 Jul 2019 13:59:32 -0400 Received: from mail-qk1-f201.google.com ([209.85.222.201]:47614 "EHLO mail-qk1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391313AbfGWR7a (ORCPT ); Tue, 23 Jul 2019 13:59:30 -0400 Received: by mail-qk1-f201.google.com with SMTP id x17so37121675qkf.14 for ; Tue, 23 Jul 2019 10:59:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=SnCe+Mtnf/4IPVX5vctz2kNHbLvxo+cXn+T1BQBMjSY=; b=H4TiQUgRdi4EHpYB8nTtg37yn9l3JyAu6VKcW2CQCTgny+vzJbtQEYhMy5VYJWq/CI KrIVgxdlW5aj4Az2DGaszv74HRn6o+lrlFDsTrBfmff9rY/9V5Ds2Mgw7VHb0yVnzniX zHDvZt7zGQFLcaS9bQ85+7iz8VxXg9au1eNOrVwptdD22wpczsG2wyPaMM6iHM1fn6oB qEapo2f+2AfPvvpteYPs6gKu7O45lNfI0gMeElG1uz04IPRB0pwyBE+bIPD+sqfvkwBv pd2Qci5+NW7JO2WHQGIVKZzYhqd9oRhn7n0TTqLXoH+DCmlggKEuaPlzaJC7NBCKpdOt X82Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=SnCe+Mtnf/4IPVX5vctz2kNHbLvxo+cXn+T1BQBMjSY=; b=uB149A3GuiYONviUprUOYiiR0fUmAUamKe98ToZHWdkeAZ8Wv60S7PU+GV6e9x3oBL sZOirtpveMEjwtm2hhIH4liL+s+LmUuZ2MUon9jsJbDqdzPEQBPlWbCE1SKbtcJVk4uP M6d1Uf86qo0/JyQpXTtx/Qvog/oqMG1Ns+R6xIoyIxh2+1OtaKtu2YDJ4s4D9KQGHzfa YGID/tKjpj4plO4AQcrOAdtbreKLPxIRnjySG+DYjVqAD8bljkizuMPDjljbTABFyiJs N0nbhnnQZgWAzKKKxEPMuKSOjnTHrM9r+5CnfApCd14M7vdWtsva0IZEbSH55i+st8Ex vw9g== X-Gm-Message-State: APjAAAWKQ1cng8NKpat3wbLSNQqu23LmqSQ+vB/BAXkHhnyPYG+KB2ZT W6NTz8kKy4uedi1lrYnq2+3dzS2LN/1Fu70k X-Google-Smtp-Source: APXvYqysiVBCmSbfWLll2amFKEEXBGqGWfbcKcVshytrTMG9pLoartROQI2FKjRVOxEkpepSHwC8IxHzKKAn6one X-Received: by 2002:ac8:66ce:: with SMTP id m14mr12433817qtp.206.1563904768802; Tue, 23 Jul 2019 10:59:28 -0700 (PDT) Date: Tue, 23 Jul 2019 19:58:44 +0200 In-Reply-To: Message-Id: <1de225e4a54204bfd7f25dac2635e31aa4aa1d90.1563904656.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.22.0.709.g102302147b-goog Subject: [PATCH v19 07/15] fs/namespace: untag user pointers in copy_mount_options From: Andrey Konovalov To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Luc Van Oostenryck , Dave Martin , Khalid Aziz , enh , Jason Gunthorpe , Christoph Hellwig , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. In copy_mount_options a user address is being subtracted from TASK_SIZE. If the address is lower than TASK_SIZE, the size is calculated to not allow the exact_copy_from_user() call to cross TASK_SIZE boundary. However if the address is tagged, then the size will be calculated incorrectly. Untag the address before subtracting. Reviewed-by: Khalid Aziz Reviewed-by: Vincenzo Frascino Reviewed-by: Kees Cook Reviewed-by: Catalin Marinas Signed-off-by: Andrey Konovalov --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 6464ea4acba9..b32eb26af8bf 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2994,7 +2994,7 @@ void *copy_mount_options(const void __user * data) * the remainder of the page. */ /* copy_from_user cannot cross TASK_SIZE ! */ - size = TASK_SIZE - (unsigned long)data; + size = TASK_SIZE - (unsigned long)untagged_addr(data); if (size > PAGE_SIZE) size = PAGE_SIZE;