From patchwork Thu Jan 11 02:02:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10156555 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 A578E605BA for ; Thu, 11 Jan 2018 02:10:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9150A2873F for ; Thu, 11 Jan 2018 02:10:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8534628743; Thu, 11 Jan 2018 02:10:35 +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 8894F2873F for ; Thu, 11 Jan 2018 02:10:34 +0000 (UTC) Received: (qmail 28391 invoked by uid 550); 11 Jan 2018 02:09:48 -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 28300 invoked from network); 11 Jan 2018 02:09:47 -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=J+XcHHVNOJAQb9tKM5ZC8hGOlYsu++RQBcLLYJMGa1I=; b=ncoFBIToxB+qIWvfbbzJOfxAey8NFgWuY6Z5uxxEdH6wFvLyRaNC3dvX32kH6YSZeQ rj/BHfUPh4h9+P64qVPRkpYlvQDsV+7uT9DnaY4GRpwT9AB9/abwl4wTL1zdAE37b3Jq nSaIdJ3Zq+4e3hjoCLazuUdi2HwoHuBeja3aQ= 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=J+XcHHVNOJAQb9tKM5ZC8hGOlYsu++RQBcLLYJMGa1I=; b=e9Cddg8fxhcjW+eU7yzMliXEVCCrBCJRKkdht+f/ZjXx4qF+OYKPBrX6otG31ADaSC qlPg6uNXIRm02z8Z+h7d/SfE1mXRCeFodtTE1TOALt37qg9VCOOAXCrHMC50HNxKivOk Ea+Vr5Nb7kqueim1nrWARX9b6mcQbQMSV/D79B4Q5nRu+CmDDwTptpMOwg0tcCrUO2Oe 17nqRlSo+5TxM8Yy0r2ubfH3gFh7H72Yp9p4GnSn4POml8KcWLFT6Vi8wrTgNWkHllht 36BkvbcYDKQYsH0QcHycQ9k3e/JY6sZsRMYfsXbEvNonlap50Kodr4G6jRB2N2PUI6b1 lrRQ== X-Gm-Message-State: AKwxytfB/Ttt52hMf2zzCdZzIiAV2ufLtWYpOvjn4aO26nZQ2tXIsO1p y6uogDa0Uoib+f7T5O6PEfkx4w== X-Google-Smtp-Source: ACJfBou8NwMVpnobf0aIoGDBNicK5p60946DbP/rxn63UQYxy1UZ71iFTogsPcEdZ8JBbbT876oLTw== X-Received: by 10.159.251.136 with SMTP id m8mr248384pls.432.1515636575695; Wed, 10 Jan 2018 18:09:35 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Christoph Hellwig , Linus Torvalds , Alexander Viro , Andrew Morton , Andy Lutomirski , 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 18:02:52 -0800 Message-Id: <1515636190-24061-21-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 20/38] vxfs: Define usercopy region in vxfs_inode slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor vxfs symlink pathnames, stored in struct vxfs_inode_info field vii_immed.vi_immed and therefore contained in the vxfs_inode slab cache, need to be copied to/from userspace. cache object allocation: fs/freevxfs/vxfs_super.c: vxfs_alloc_inode(...): ... vi = kmem_cache_alloc(vxfs_inode_cachep, GFP_KERNEL); ... return &vi->vfs_inode; fs/freevxfs/vxfs_inode.c: cxfs_iget(...): ... inode->i_link = vip->vii_immed.vi_immed; 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 vxfs_inode 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: Christoph Hellwig Signed-off-by: Kees Cook --- fs/freevxfs/vxfs_super.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c index f989efa051a0..48b24bb50d02 100644 --- a/fs/freevxfs/vxfs_super.c +++ b/fs/freevxfs/vxfs_super.c @@ -332,9 +332,13 @@ vxfs_init(void) { int rv; - vxfs_inode_cachep = kmem_cache_create("vxfs_inode", + vxfs_inode_cachep = kmem_cache_create_usercopy("vxfs_inode", sizeof(struct vxfs_inode_info), 0, - SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, NULL); + SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD, + offsetof(struct vxfs_inode_info, vii_immed.vi_immed), + sizeof_field(struct vxfs_inode_info, + vii_immed.vi_immed), + NULL); if (!vxfs_inode_cachep) return -ENOMEM; rv = register_filesystem(&vxfs_fs_type);