From patchwork Thu Jan 11 02:02:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10156559 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 BF9C6605BA for ; Thu, 11 Jan 2018 02:10:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AE4252873F for ; Thu, 11 Jan 2018 02:10:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A250428743; Thu, 11 Jan 2018 02:10:45 +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 A1BEF2873F for ; Thu, 11 Jan 2018 02:10:44 +0000 (UTC) Received: (qmail 28508 invoked by uid 550); 11 Jan 2018 02:09:50 -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 28323 invoked from network); 11 Jan 2018 02:09:48 -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=hHtbKFKBbHrG1TnQjzBGyPhAG6ELUBqSox0kQKy0IJ7aUpe+DpIX2IRr5J+95kB9Tc Hysf8DYOUZ9T9qdpRaYXtvMUFyTl3LdfDjMxXNKNed0YgC/xfyQ6gDEd5aw2L04bZkc/ GsxJ9H+q20YM3x3u+1pekkUeZPn7EhdZ++4Lk= 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=f8i9wlplLxKr1DjlvDy4fUe+I8A+TLg4D7lhYvApASPiWh3BjpB7wgXmXoC5mSMR78 +lFzfE8CS5LMTAlpwLtOYLwMqB8CigyQmT3TjDzCYcL7VA9kiWdetxbicX7K7fagWtkN UHWbZJP64Oxm6ynb2jC+Vb/hwGwO5F4NxevKBfYnGCe1LVvtm61i2HRFou4n/gcrq4J2 Q7uMWqnYemeBr/n341D6Xy0XC/WIJABKoaQZ3tR5hUNDspokN2bzSzW9kzOIig+5uPzD hh6govsHiEf8xWGxgxLDlhThqKxKahhcdja/7mcAhDgiHKAIWkflqTuZq35OSCREiN24 M1UA== X-Gm-Message-State: AKwxytdQ1KbfljfoHMBClzBX3/NasM0Dc71FeBNrj5N7fNbB8sgyUJd1 0wTWLzgIqKJwEXxZAswershTAg== X-Google-Smtp-Source: ACJfBouY2Y6X/T6HVhKUN/J/vbIpbVK7YjUc3Mo5VJZbGC85AmBqklmACAwthIxtrWeoTDmjcFeXjw== X-Received: by 10.101.99.211 with SMTP id n19mr2733895pgv.147.1515636576630; Wed, 10 Jan 2018 18:09:36 -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: Wed, 10 Jan 2018 18:02:53 -0800 Message-Id: <1515636190-24061-22-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1515636190-24061-1-git-send-email-keescook@chromium.org> References: <1515636190-24061-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH 21/38] 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);