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: 10153349 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 C5E08602CA for ; Tue, 9 Jan 2018 21:00:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BBC6625404 for ; Tue, 9 Jan 2018 21:00:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BA2CB25E13; Tue, 9 Jan 2018 21:00:05 +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 4721C25404 for ; Tue, 9 Jan 2018 21:00:04 +0000 (UTC) Received: (qmail 9380 invoked by uid 550); 9 Jan 2018 20:57:25 -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 8052 invoked from network); 9 Jan 2018 20:57:16 -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=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=XBM4Ts9BI35stLjzy/M/+7G4RFH++b3GF9nfr/oM7vUGBgTr6FqGygh564U10wftLe W2Yj3C9UiH19eDPI+JVQs8umSy/+MA112g+LoJyBNwjCAe9aUt4BY7etVCkJhWGYxW6U sZEJAyLrA4hWs9P5B7PckUw23ccCYEUJ4zwtSH66S/0a5vfDiCHcAs6/mrhlMOyINDe1 tnJ9k5gXoS1t/+dUXoA9owyta/xJH2v/YfThpiwv75rVOHYF20yC78LoBR2hY1k1Mi91 vIU7LPju5T/1uWaAcPR6fYKVI+6gXJFLzTagbSTt1d6yFQGmElQdUtV0qUTNsnTZogBC 9qLA== X-Gm-Message-State: AKGB3mJc2sbph8cLKeE7lagj8AfPbZwNCOPqX0gPVhTfHLrHjDIA+rDX CWsUEot3qwhrc+B0ZO480eKA4Q== 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) 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 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> Subject: [kernel-hardening] [PATCH 18/36] cifs: Define usercopy region in cifs_request slab cache X-Virus-Scanned: ClamAV using ClamSMTP 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);