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: 9926301 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 02D3960375 for ; Mon, 28 Aug 2017 21:40:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E29DB2886C for ; Mon, 28 Aug 2017 21:40:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DF80A28802; Mon, 28 Aug 2017 21:40:08 +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=-2.4 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, URIBL_BLACK autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id E924528811 for ; Mon, 28 Aug 2017 21:40:03 +0000 (UTC) Received: (qmail 13744 invoked by uid 550); 28 Aug 2017 21:35:53 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 12241 invoked from network); 28 Aug 2017 21:35:39 -0000 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=gCxzVuJ5zryLcuALLwCoiPB4yKYTYrj/CazxhaXyhomQs0MerI9TNUw+CwLhd31tBo tAYJgwX4khoG2Gg39dlimiVnAcBv48TKSAVFgB7etvjMqYCFbJdH3qSTgUyCJ5+LBIvA ASg5A2YszCD3qPqgywuS6x418RBayNhuVZklOiGjUKDQdEQca9EgyUh4zQppxqGUERgL g7q48WF6H43wUU7PzWgULZWbYrJvKcScKkfGYAFl1z1bUdfPzUorF7dww8Q6ebi4ojvM SnUdp3nYEujArcoiCQrWt6/xY1DkcQSoOveT9Y5GNKDvJpBvQff4NdwpcYc51Ob9fW7v sLxg== X-Gm-Message-State: AHYfb5jRZChHGuyIM3q52R4Jyn2vlDpdDofiGniP+HqLHSrtP30VWXlw 5VoWHRmbPx4Z0Iax X-Received: by 10.84.217.152 with SMTP id p24mr2413436pli.162.1503956127712; Mon, 28 Aug 2017 14:35:27 -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 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> Subject: [kernel-hardening] [PATCH v2 15/30] xfs: Define usercopy region in xfs_inode slab cache 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;