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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 1622AC5DF63 for ; Wed, 6 Nov 2019 19:02:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4CA220869 for ; Wed, 6 Nov 2019 19:02:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SRRkmXEw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727414AbfKFTCs (ORCPT ); Wed, 6 Nov 2019 14:02:48 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:31195 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727411AbfKFTCr (ORCPT ); Wed, 6 Nov 2019 14:02:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573066966; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=kxdmMHHUCiwD411i+Ffa8FviPIgnmJlk/z+ts63ZbWE=; b=SRRkmXEwJNvL5e7dhX6bb/gdDYlKNsZnJKlx9z7uiExWrY7Y3NnHiuJ1DpfF1ghq0dFx8d aip312DtXPHLrIaTUmxXw9lXDFXXU17g8xYkq7BapJpqFND1ZJQ/TjtoUrB+ZnPZVegG9E xPd3GWQQS7JILyhz6j4aoIyxQthTHUI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-220-7sL43AozOKCWRjovtywQqw-1; Wed, 06 Nov 2019 14:02:44 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E41131005500; Wed, 6 Nov 2019 19:02:43 +0000 (UTC) Received: from max.com (unknown [10.40.206.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id B7A5160872; Wed, 6 Nov 2019 19:02:42 +0000 (UTC) From: Andreas Gruenbacher To: Alexander Viro , linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig , Andreas Gruenbacher Subject: [PATCH] fs: Fix overflow in block_page_mkwrite Date: Wed, 6 Nov 2019 20:02:39 +0100 Message-Id: <20191106190239.20860-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: 7sL43AozOKCWRjovtywQqw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On architectures where ssize_t is wider than pgoff_t, the expression ((page->index + 1) << PAGE_SHIFT) can overflow. Rewrite to use the page offset, which we already compute here anyway. Signed-off-by: Andreas Gruenbacher --- fs/buffer.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index 86a38b979323..da3f33b70249 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2459,21 +2459,21 @@ int block_page_mkwrite(struct vm_area_struct *vma, = struct vm_fault *vmf, =09struct page *page =3D vmf->page; =09struct inode *inode =3D file_inode(vma->vm_file); =09unsigned long end; -=09loff_t size; +=09loff_t offset, size; =09int ret; =20 =09lock_page(page); =09size =3D i_size_read(inode); -=09if ((page->mapping !=3D inode->i_mapping) || -=09 (page_offset(page) > size)) { +=09offset =3D page_offset(page); +=09if (page->mapping !=3D inode->i_mapping || offset > size) { =09=09/* We overload EFAULT to mean page got truncated */ =09=09ret =3D -EFAULT; =09=09goto out_unlock; =09} =20 =09/* page is wholly or partially inside EOF */ -=09if (((page->index + 1) << PAGE_SHIFT) > size) -=09=09end =3D size & ~PAGE_MASK; +=09if (offset > size - PAGE_SIZE) +=09=09end =3D offset_in_page(size); =09else =09=09end =3D PAGE_SIZE; =20 --=20 2.20.1