From patchwork Tue Jan 9 20:55:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 857778 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-cifs-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.b="afNjOAwL"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3zGPyW5GgGz9s75 for ; Wed, 10 Jan 2018 08:13:55 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753898AbeAIVMz (ORCPT ); Tue, 9 Jan 2018 16:12:55 -0500 Received: from mail-pf0-f195.google.com ([209.85.192.195]:35332 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758284AbeAIU5F (ORCPT ); Tue, 9 Jan 2018 15:57:05 -0500 Received: by mail-pf0-f195.google.com with SMTP id t12so6599488pfg.2 for ; Tue, 09 Jan 2018 12:57:05 -0800 (PST) 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=KMjmaJOqJJKmi5iyPNqoLhDPnngT3NZrdMVoOHoyv88=; b=afNjOAwLUk71vJpKsj7HzEDpRdxk4y7xT62b7u3xa2/FHKe9mEEX7fBd0LK+p7zYN3 K7Q6vFw0MZY16Um7i15s3lJZR0tNqDY3O5FCzOW7y2Tsvusrh12+gXLWn2cdkxGyan2V L5x0zljeHcRQk8NCJi1ntGXXYZ015IUUAVWs0= 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=KMjmaJOqJJKmi5iyPNqoLhDPnngT3NZrdMVoOHoyv88=; b=p3QmHPC37C3zG/tdSjNKd0IMYicVRYznfyswMbepXePPQfHI6/2OhoKpIBdte7Coty mxDZfogP8cn5GKonFH4FJhHTiQ8u3VDTuI3XfRw2rjeMZErsSP86Ubx1wTAN5WV1LtgX 8vIG9FCAHDTI/OmscE6AVJlpm7eFJ70Ocw/r178BrtJwpx/vMhesByYPrDltXzjBPa1g /L/OX8X/edc/x+wmsTlA4EK7LoSr2ZdIogxEAKEOlLTpiphoteO5c35k5wdxa9SRmU8W VyKbHsplLt1zXZJDzqwLsy5jzaXXmfdwmX8uPdpxYQoDf28lYvIk4xCDP2V98UemF+xb dJ2g== X-Gm-Message-State: AKGB3mIYDQVNrNXdDd7JemJ8WtNDuqjN8VgwdWSf6UvJcMCEz1rccW9G bB7CWbfNQquDtAsOYVHeeSRoGQ== X-Google-Smtp-Source: ACJfBossLq5UiG7nP3Nx1M0F4C8vmWxfPaFihsxXlGw8L/IKhrZ7WTqdqW/kC8GI1g3cS+e5ijqGaQ== X-Received: by 10.98.6.130 with SMTP id 124mr14676532pfg.8.1515531424912; Tue, 09 Jan 2018 12:57:04 -0800 (PST) Received: from www.outflux.net (173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133]) by smtp.gmail.com with ESMTPSA id g19sm31568660pfb.65.2018.01.09.12.57.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Jan 2018 12:57:03 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Steve French , linux-cifs@vger.kernel.org, Linus Torvalds , Alexander Viro , Andrew Morton , Andy Lutomirski , Christoph Hellwig , Christoph Lameter , "David S. Miller" , Laura Abbott , Mark Rutland , "Martin K. Petersen" , Paolo Bonzini , Christian Borntraeger , Christoffer Dall , Dave Kleikamp , Jan Kara , Luis de Bethencourt , Marc Zyngier , Rik van Riel , Matthew Garrett , linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Subject: [PATCH 18/36] cifs: Define usercopy region in cifs_request slab cache Date: Tue, 9 Jan 2018 12:55:47 -0800 Message-Id: <1515531365-37423-19-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1515531365-37423-1-git-send-email-keescook@chromium.org> References: <1515531365-37423-1-git-send-email-keescook@chromium.org> Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org From: David Windsor CIFS request buffers, stored in the cifs_request slab cache, need to be copied to/from userspace. cache object allocation: fs/cifs/cifsfs.c: cifs_init_request_bufs(): ... cifs_req_poolp = mempool_create_slab_pool(cifs_min_rcv, cifs_req_cachep); fs/cifs/misc.c: cifs_buf_get(): ... ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS); ... return ret_buf; In support of usercopy hardening, this patch defines a region in the cifs_request 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 dynamically sized copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is verbatim 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: Steve French Cc: linux-cifs@vger.kernel.org Signed-off-by: Kees Cook --- fs/cifs/cifsfs.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 31b7565b1617..29f4b0290fbd 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -1231,9 +1231,11 @@ cifs_init_request_bufs(void) cifs_dbg(VFS, "CIFSMaxBufSize %d 0x%x\n", CIFSMaxBufSize, CIFSMaxBufSize); */ - cifs_req_cachep = kmem_cache_create("cifs_request", + cifs_req_cachep = kmem_cache_create_usercopy("cifs_request", CIFSMaxBufSize + max_hdr_size, 0, - SLAB_HWCACHE_ALIGN, NULL); + SLAB_HWCACHE_ALIGN, 0, + CIFSMaxBufSize + max_hdr_size, + NULL); if (cifs_req_cachep == NULL) return -ENOMEM; @@ -1259,9 +1261,9 @@ cifs_init_request_bufs(void) more SMBs to use small buffer alloc and is still much more efficient to alloc 1 per page off the slab compared to 17K (5page) alloc of large cifs buffers even when page debugging is on */ - cifs_sm_req_cachep = kmem_cache_create("cifs_small_rq", + cifs_sm_req_cachep = kmem_cache_create_usercopy("cifs_small_rq", MAX_CIFS_SMALL_BUFFER_SIZE, 0, SLAB_HWCACHE_ALIGN, - NULL); + 0, MAX_CIFS_SMALL_BUFFER_SIZE, NULL); if (cifs_sm_req_cachep == NULL) { mempool_destroy(cifs_req_poolp); kmem_cache_destroy(cifs_req_cachep);