From patchwork Mon Aug 28 21:34:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9926295 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 B3D4C60383 for ; Mon, 28 Aug 2017 21:39:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A85E1287D2 for ; Mon, 28 Aug 2017 21:39:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9D45A287D5; Mon, 28 Aug 2017 21:39:00 +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 2A7A9287D6 for ; Mon, 28 Aug 2017 21:38:56 +0000 (UTC) Received: (qmail 13701 invoked by uid 550); 28 Aug 2017 21:35:51 -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 12283 invoked from network); 28 Aug 2017 21:35:40 -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=78PkItnmHHE4XmBKrwQW0Z4l9f2I/SjGvrmyoOkINk0=; b=Neblj7tq82cAL46qssrrCvQ8U/a2Y778FehDlUMlqHNIQJe12HL5VAxNf3AVhV8rY8 TQMy4ExBVT8WYbsPb93NV8nbkINOdSyxZWU4J2btyRkYKVtMEkJavNl3eByXTKVhCFOh +A6dNYaZ/zBpH7PGEPf+d7FlAvN42vO9Znpcs= 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=78PkItnmHHE4XmBKrwQW0Z4l9f2I/SjGvrmyoOkINk0=; b=RofQ45NA0imVdnfbP/IMp9DIZtwP7cqJ3ljQDikYE8BcqcITf4aDU5ZHEW2SqjXoSH h+fhTGBlFREfHo6+GLWWvixTJkQvsvY4DlnjXV8y0MApB5xh7AMNLLkDf7eEDV+fznk5 wGgK25+2An0BZxh3ifK+nsOcTYVT1s0tnfo6SfZ2EIiB6W+dNRKXCFeTMmA3Wt/DOhxA fGcyeiC/LX+zAe86DDquJkbDA8S0l6/PL2f0ptmSmKsb6mAbwhLh7VMWX4Y2BMMkAR2B CWLjlzfJuO0hyHKGFvZidEaeLjr0D8iCigd8g25qVj4dh8he1WLYKawyZyQ02pvEnIkp 4Kkg== X-Gm-Message-State: AHYfb5hTiD1UKcZxuw4nqE0ZZHphAcT5UvhxNTEVqAx3/JaGvGquPqtB KS2hhdUhtLwXTCRLFj9FNA== X-Received: by 10.84.215.152 with SMTP id l24mr2278317pli.193.1503956128411; Mon, 28 Aug 2017 14:35:28 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Evgeniy Dushistov , linux-mm@kvack.org, kernel-hardening@lists.openwall.com Date: Mon, 28 Aug 2017 14:34:54 -0700 Message-Id: <1503956111-36652-14-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 13/30] ufs: Define usercopy region in ufs_inode_cache slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor The ufs symlink pathnames, stored in struct ufs_inode_info.i_u1.i_symlink and therefore contained in the ufs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/ufs/super.c: ufs_alloc_inode(...): ... ei = kmem_cache_alloc(ufs_inode_cachep, GFP_NOFS); ... return &ei->vfs_inode; fs/ufs/ufs.h: UFS_I(struct inode *inode): return container_of(inode, struct ufs_inode_info, vfs_inode); fs/ufs/namei.c: ufs_symlink(...): ... inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink; example usage trace: readlink_copy+0x43/0x70 vfs_readlink+0x62/0x110 SyS_readlinkat+0x100/0x130 fs/namei.c: readlink_copy(..., link): ... copy_to_user(..., link, len); (inlined in vfs_readlink) generic_readlink(dentry, ...): struct inode *inode = d_inode(dentry); const char *link = inode->i_link; ... readlink_copy(..., link); In support of usercopy hardening, this patch defines a region in the ufs_inode_cache 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: Evgeniy Dushistov Signed-off-by: Kees Cook --- fs/ufs/super.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index 0a4f58a5073c..646f971067bc 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1466,11 +1466,14 @@ static void init_once(void *foo) static int __init init_inodecache(void) { - ufs_inode_cachep = kmem_cache_create("ufs_inode_cache", - sizeof(struct ufs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT), - init_once); + ufs_inode_cachep = kmem_cache_create_usercopy("ufs_inode_cache", + sizeof(struct ufs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + offsetof(struct ufs_inode_info, i_u1.i_symlink), + sizeof_field(struct ufs_inode_info, + i_u1.i_symlink), + init_once); if (ufs_inode_cachep == NULL) return -ENOMEM; return 0;