From patchwork Thu Jan 11 02:02:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 10156693 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 42A6D60231 for ; Thu, 11 Jan 2018 02:20:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2D2DD2874F for ; Thu, 11 Jan 2018 02:20:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 21ABA28753; Thu, 11 Jan 2018 02:20:28 +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 4A7922874F for ; Thu, 11 Jan 2018 02:20:27 +0000 (UTC) Received: (qmail 28539 invoked by uid 550); 11 Jan 2018 02:19:52 -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 28416 invoked from network); 11 Jan 2018 02:19:49 -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=YKnoLn5y8s2UpHwNQGuC3A7deJajJSC7iR0HkqVn8JQ=; b=MOL98VGcZHEZNVX1V3JbtDAUtQ6LHsvv2omifn9BL58h6d4AoBAuJ0ur9bXptgHNA3 i6/+jVvO+kEHqS4pd5T71PhbsRRMsBmihBb7EU2yDgzsNRN0uTcF0ukPM4J18nJb0nBM la8Nmy3mC+aWorkBEXq+SncVVp3zuhhmyv9a0= 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=YKnoLn5y8s2UpHwNQGuC3A7deJajJSC7iR0HkqVn8JQ=; b=OCqoVmpU9Nq9uiIfuwTDhlxCjHsz2U3dtHqTvW0io+VKKGHBlvNlCppkh98IZu9vsV RVyhWB+gOqFnDubjMXef2bu9EBMkG0Ocer9N6uyHWHX5Cy5bKgYe/ml9Zy7dAevLGqoz OeOoYvO9lFaiJNSW1ciuBmE36dKQ1GO/+oMmSWk3AwAFo7zIBCM6BBytL3idLzpOaA/g 50KonS8wgZxzN/6yhf/1uD23PPVOllTerPaJm/gyiri/mdIJz9eKymLeJbPUI/uLijQP Jn8eXgBJlxd0q1fT+ppMthGxSaAf9qjUypPEPlvsjmsk5/Pkgt73NR48DDrJQ4RHbMR4 Xz6A== X-Gm-Message-State: AKGB3mKbTByxJ0Q2yuCnJlkvFzRdZRDMt8GQmtVocDMHPZLi9N1vyOgu jAGlYQ8rpEN1qQ3Vh8rpulD9JA== X-Google-Smtp-Source: ACJfBos+Z6q8pxTEiLPZrfsAt85vGn6PMpVI1E39WHwxEuQh71PjCwJ3XhsIoXbRfFVraF0PpaJ/+Q== X-Received: by 10.98.79.12 with SMTP id d12mr11414019pfb.186.1515637177486; Wed, 10 Jan 2018 18:19:37 -0800 (PST) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Luis de Bethencourt , Salah Triki , 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 , 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 18:02:48 -0800 Message-Id: <1515636190-24061-17-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 16/38] befs: Define usercopy region in befs_inode_cache slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor befs symlink pathnames, stored in struct befs_inode_info.i_data.symlink and therefore contained in the befs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/befs/linuxvfs.c: befs_alloc_inode(...): ... bi = kmem_cache_alloc(befs_inode_cachep, GFP_KERNEL); ... return &bi->vfs_inode; befs_iget(...): ... strlcpy(befs_ino->i_data.symlink, raw_inode->data.symlink, BEFS_SYMLINK_LEN); ... inode->i_link = befs_ino->i_data.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 befs_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: Luis de Bethencourt Cc: Salah Triki Signed-off-by: Kees Cook Acked-by: Luis de Bethencourt --- fs/befs/linuxvfs.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c index ee236231cafa..af2832aaeec5 100644 --- a/fs/befs/linuxvfs.c +++ b/fs/befs/linuxvfs.c @@ -444,11 +444,15 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino) static int __init befs_init_inodecache(void) { - befs_inode_cachep = kmem_cache_create("befs_inode_cache", - sizeof (struct befs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT), - init_once); + befs_inode_cachep = kmem_cache_create_usercopy("befs_inode_cache", + sizeof(struct befs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + offsetof(struct befs_inode_info, + i_data.symlink), + sizeof_field(struct befs_inode_info, + i_data.symlink), + init_once); if (befs_inode_cachep == NULL) return -ENOMEM;