From patchwork Mon Aug 28 21:34:56 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9926247 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5452360375 for ; Mon, 28 Aug 2017 21:36:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 47BBC287D2 for ; Mon, 28 Aug 2017 21:36:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3B7E9287D7; Mon, 28 Aug 2017 21:36:34 +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=-5.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, URIBL_BLACK 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 A9C3B287D2 for ; Mon, 28 Aug 2017 21:36:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751263AbdH1VgU (ORCPT ); Mon, 28 Aug 2017 17:36:20 -0400 Received: from mail-pg0-f54.google.com ([74.125.83.54]:35407 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751589AbdH1Vf2 (ORCPT ); Mon, 28 Aug 2017 17:35:28 -0400 Received: by mail-pg0-f54.google.com with SMTP id 63so4970950pgc.2 for ; Mon, 28 Aug 2017 14:35:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=DI6AZ0VrY7a3rBeIJqKk0k9HCGfwqO+sZ//akucZR68=; b=U++Ax4/CrRcnmITxI1xQLYXQGv8Q2Q/zMeO4pcUmzB7fPoAQxx3KbxLeawdXUMHeMs zpiQ7pasveALK4xZkF7ET3bNHwllcH/u10EBD0h0tka4vx8A4KgK2lktGbIDB2+QlEas A1GQ8eXAjAQ0fYTNiam1MF7Xtdlqd599xUKzc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=DI6AZ0VrY7a3rBeIJqKk0k9HCGfwqO+sZ//akucZR68=; b=mhK+dFoFRrQoSVssv4jTRkyCJtYPNuCFpCt+g+fXWsauvmD2xDeH5EWsRK8DnEw6sU FUcJPtbmwl2jfKtY0NrX0maE/SypmFm7HieOoon5rTMjRyzTAx6z/FtpwEPD3wN15Mmb Jrx2XaDbzjn8j/ZGZhBrQ6R8k8siLZyCqVkes+PcJeshUb/u3rLjbmcTVquM3Zw5/Kwf /HI5I8lCk2hoHHS2dL7zxYQ7RXOoRZy966kkfw/YTzQKTjvJBgNdogi+hUfI2Ww46fUF z7PZcSv0FlOq+mxfC/HfNyf1V8pnKwPwXuNSZdjwjXS1b0tN0d7ObjbLyN1RJ9ksV15Q clOg== X-Gm-Message-State: AHYfb5iWxaoJ2Ufvfx0qdpEiukeLUeK64UAjfxhZzvsu68XTTe017MYS fYhXczj4yFG+ultF X-Received: by 10.84.217.152 with SMTP id p24mr2413436pli.162.1503956127712; Mon, 28 Aug 2017 14:35:27 -0700 (PDT) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id b29sm2485369pfh.22.2017.08.28.14.35.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Aug 2017 14:35:24 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , "Darrick J. Wong" , linux-xfs@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Subject: [PATCH v2 15/30] xfs: Define usercopy region in xfs_inode slab cache Date: Mon, 28 Aug 2017 14:34:56 -0700 Message-Id: <1503956111-36652-16-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503956111-36652-1-git-send-email-keescook@chromium.org> References: <1503956111-36652-1-git-send-email-keescook@chromium.org> Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor The XFS inline inode data, stored in struct xfs_inode_t field i_df.if_u2.if_inline_data and therefore contained in the xfs_inode slab cache, needs to be copied to/from userspace. cache object allocation: fs/xfs/xfs_icache.c: xfs_inode_alloc(...): ... ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP); fs/xfs/libxfs/xfs_inode_fork.c: xfs_init_local_fork(...): ... if (mem_size <= sizeof(ifp->if_u2.if_inline_data)) ifp->if_u1.if_data = ifp->if_u2.if_inline_data; ... fs/xfs/xfs_symlink.c: xfs_symlink(...): ... xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen); example usage trace: readlink_copy+0x43/0x70 vfs_readlink+0x62/0x110 SyS_readlinkat+0x100/0x130 fs/xfs/xfs_iops.c: (via inode->i_op->get_link) xfs_vn_get_link_inline(...): ... return XFS_I(inode)->i_df.if_u1.if_data; fs/namei.c: readlink_copy(..., link): ... copy_to_user(..., link, len); generic_readlink(dentry, ...): struct inode *inode = d_inode(dentry); const char *link = inode->i_link; ... if (!link) { link = inode->i_op->get_link(dentry, inode, &done); ... readlink_copy(..., link); In support of usercopy hardening, this patch defines a region in the xfs_inode slab cache in which userspace copy operations are allowed. This region is known as the slab cache's usercopy region. Slab caches can now check that each copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor [kees: adjust commit log, provide usage trace] Cc: "Darrick J. Wong" Cc: linux-xfs@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Darrick J. Wong --- fs/xfs/kmem.h | 10 ++++++++++ fs/xfs/xfs_super.c | 7 +++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h index 4d85992d75b2..08358f38dee6 100644 --- a/fs/xfs/kmem.h +++ b/fs/xfs/kmem.h @@ -110,6 +110,16 @@ kmem_zone_init_flags(int size, char *zone_name, unsigned long flags, return kmem_cache_create(zone_name, size, 0, flags, construct); } +static inline kmem_zone_t * +kmem_zone_init_flags_usercopy(int size, char *zone_name, unsigned long flags, + size_t useroffset, size_t usersize, + void (*construct)(void *)) +{ + return kmem_cache_create_usercopy(zone_name, size, 0, flags, + useroffset, usersize, construct); +} + + static inline void kmem_zone_free(kmem_zone_t *zone, void *ptr) { diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c index 38aaacdbb8b3..6ca428c6f943 100644 --- a/fs/xfs/xfs_super.c +++ b/fs/xfs/xfs_super.c @@ -1829,9 +1829,12 @@ xfs_init_zones(void) goto out_destroy_efd_zone; xfs_inode_zone = - kmem_zone_init_flags(sizeof(xfs_inode_t), "xfs_inode", + kmem_zone_init_flags_usercopy(sizeof(xfs_inode_t), "xfs_inode", KM_ZONE_HWALIGN | KM_ZONE_RECLAIM | KM_ZONE_SPREAD | - KM_ZONE_ACCOUNT, xfs_fs_inode_init_once); + KM_ZONE_ACCOUNT, + offsetof(xfs_inode_t, i_df.if_u2.if_inline_data), + sizeof_field(xfs_inode_t, i_df.if_u2.if_inline_data), + xfs_fs_inode_init_once); if (!xfs_inode_zone) goto out_destroy_efi_zone;