From patchwork Thu Jan 11 02:02:49 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10156579 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 A772D605BA for ; Thu, 11 Jan 2018 02:11:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 962602874B for ; Thu, 11 Jan 2018 02:11:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 89B9C2874E; Thu, 11 Jan 2018 02:11:54 +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 8C6AD2874B for ; Thu, 11 Jan 2018 02:11:53 +0000 (UTC) Received: (qmail 29917 invoked by uid 550); 11 Jan 2018 02:10:06 -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 29746 invoked from network); 11 Jan 2018 02:09:59 -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=JqFi5G7opA+pmMKcq45uOyjduNd/cOyB71gO8jYxW4E=; b=oa72h4U3rwr4J61m+IsPFPK4Yw3Wr41FwP6/vzpSSbV4aGFlHSj0upN41bXfCTYmCF IqnkfdluasBUfiabVkwVYlK7EB+qICDYffkVakLppyBXTTh4dkuHIJhqdnzHjuE3Vm4A H0DA+Qc0uUHec7i0LsbI3eEOfkWbqBv6IgomI= 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=JqFi5G7opA+pmMKcq45uOyjduNd/cOyB71gO8jYxW4E=; b=itVaudB1Vhokf+zUCeKm6jyThO24SKMK14MxzbyFJ30x6CkzmrdSfd99a0qbFhawqt PLyvFUbdX5bQRA1diatSK6zydvCtc5vE6fM4m3AHYOxRprm32e/AFxBHYOp80+dmSlci GntalgNCIGXrRQ9u38jz/28YxfZ2yXCtBshS722yjS7JJshpKgj8our130H4k2PEkDIF ti73gkeSI6tWG+drDlYv6CJpM+YeAMVYmP8c6spjnOKIfyfCG3vTNO5jhwlwJYNl/8a4 7sQ4+yJhKIIggpDuOoXDr3jHJ8L0n3Q0TTpyhoFdTsQ1WKIi2uW+V00FxPuWjg+EN4c+ 2Wbg== X-Gm-Message-State: AKGB3mIqlFNyAJh6lAet/g5ETBrr+21Z/U7NLx2bUAFbE0Vcd2oQBUZi QSQCEkGPgO88d7oVM3W5P2eCLA== X-Google-Smtp-Source: ACJfBot9TeXq2kD7Ky7A5VKy7oFL/5yovBVcdwhrjgQbqYll2J20kH8K0cMcdbNCPq4rxDtfZRKLew== X-Received: by 10.99.94.69 with SMTP id s66mr16256282pgb.155.1515636587484; Wed, 10 Jan 2018 18:09:47 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Boaz Harrosh , 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 18:02:49 -0800 Message-Id: <1515636190-24061-18-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 17/38] exofs: Define usercopy region in exofs_inode_cache slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor The exofs short symlink names, stored in struct exofs_i_info.i_data and therefore contained in the exofs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/exofs/super.c: exofs_alloc_inode(...): ... oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL); ... return &oi->vfs_inode; fs/exofs/namei.c: exofs_symlink(...): ... inode->i_link = (char *)oi->i_data; 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 exofs_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 dynamically sized 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: Boaz Harrosh Signed-off-by: Kees Cook --- fs/exofs/super.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/exofs/super.c b/fs/exofs/super.c index 819624cfc8da..e5c532875bb7 100644 --- a/fs/exofs/super.c +++ b/fs/exofs/super.c @@ -192,10 +192,13 @@ static void exofs_init_once(void *foo) */ static int init_inodecache(void) { - exofs_inode_cachep = kmem_cache_create("exofs_inode_cache", + exofs_inode_cachep = kmem_cache_create_usercopy("exofs_inode_cache", sizeof(struct exofs_i_info), 0, SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | - SLAB_ACCOUNT, exofs_init_once); + SLAB_ACCOUNT, + offsetof(struct exofs_i_info, i_data), + sizeof_field(struct exofs_i_info, i_data), + exofs_init_once); if (exofs_inode_cachep == NULL) return -ENOMEM; return 0;