From patchwork Tue Jan 9 20:55:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10153335 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 303CE602CA for ; Tue, 9 Jan 2018 20:59:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 24A552040D for ; Tue, 9 Jan 2018 20:59:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 187E1204C4; Tue, 9 Jan 2018 20:59:14 +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 18E332040D for ; Tue, 9 Jan 2018 20:59:12 +0000 (UTC) Received: (qmail 8147 invoked by uid 550); 9 Jan 2018 20:57:19 -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 7991 invoked from network); 9 Jan 2018 20:57:14 -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=ArY4mmJZq2qSxtBfA5c8RBIOZN8HYA220FFpy+yyeoY=; b=VCSjRWq7ZIt1vecNeFHBrTRAl1ToOBJn+K6h54joSZ6Yt3oB7bkq+CU/9JqXYVKk8u XetZXIFXdAYaeCxDpYFYcqXFoucuVPGede039L0KIYAG5QxSbs2s/Md2N+C5SkvKIpP/ v0n6uQdKrPuTbyvHW2XlPuvz814hJ32cRUCdc= 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=ArY4mmJZq2qSxtBfA5c8RBIOZN8HYA220FFpy+yyeoY=; b=ikbc7HKThstzrB3pOWpFaIDTjisMNSHKhvCBPDNKTCKge8cI0WGQanN/N2VYyi/Z2A JoxghPKazWJjxEFLsoRtoPUoplhl+wNXGdIw1VsZq2CH5M7ui7U+6U6MFvUIyGsTZc67 4qAgb3CzN1ETCxBMXNR/f1Dv5If4jNI+UyjBAAbprFR0yHTTYLmi+aeJjJRKEPDXxbv9 czXPbdu4H5b1/kDrygzBpO8lBmWu3ndkSh6kM4qWQ6408loyJrlVXLyCM935vHLukUvO Ay/ehzxrXXbVfR2hK4I4RDo3fT76c0bzODq+z0FSYZzIgFQO0LfXsWmQYfnzjVg9Xn40 Ethw== X-Gm-Message-State: AKGB3mI4NRk9DrxSSRjc3/39Zs4aRcUIb4qaQaQg2jgvodLKl7egQDks NlO1utv9IbNsFn7v8yEiV4FIIw== X-Google-Smtp-Source: ACJfBou6UBgIjnrzWcxIEGXBeVlJsDK8IAoypo0J+QCFNMQkhCGhMfY1g0RWEehkI3FDJB1a3zPQNg== X-Received: by 10.84.240.131 with SMTP id z3mr10647631plk.404.1515531423094; Tue, 09 Jan 2018 12:57:03 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Evgeniy Dushistov , 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 12:55:45 -0800 Message-Id: <1515531365-37423-17-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 16/36] ufs: Define usercopy region in ufs_inode_cache slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor The ufs symlink pathnames, stored in struct ufs_inode_info.i_u1.i_symlink and therefore contained in the ufs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/ufs/super.c: ufs_alloc_inode(...): ... ei = kmem_cache_alloc(ufs_inode_cachep, GFP_NOFS); ... return &ei->vfs_inode; fs/ufs/ufs.h: UFS_I(struct inode *inode): return container_of(inode, struct ufs_inode_info, vfs_inode); fs/ufs/namei.c: ufs_symlink(...): ... inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink; 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 ufs_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: Evgeniy Dushistov Signed-off-by: Kees Cook --- fs/ufs/super.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index 4d497e9c6883..652a77702aec 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1466,11 +1466,14 @@ static void init_once(void *foo) static int __init init_inodecache(void) { - ufs_inode_cachep = kmem_cache_create("ufs_inode_cache", - sizeof(struct ufs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT), - init_once); + ufs_inode_cachep = kmem_cache_create_usercopy("ufs_inode_cache", + sizeof(struct ufs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + offsetof(struct ufs_inode_info, i_u1.i_symlink), + sizeof_field(struct ufs_inode_info, + i_u1.i_symlink), + init_once); if (ufs_inode_cachep == NULL) return -ENOMEM; return 0;