{"id":816515,"url":"http://patchwork.ozlabs.org/api/patches/816515/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/patch/1505940337-79069-5-git-send-email-keescook@chromium.org/","project":{"id":7,"url":"http://patchwork.ozlabs.org/api/projects/7/?format=json","name":"Linux network development","link_name":"netdev","list_id":"netdev.vger.kernel.org","list_email":"netdev@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<1505940337-79069-5-git-send-email-keescook@chromium.org>","list_archive_url":null,"date":"2017-09-20T20:45:10","name":"[v3,04/31] dcache: Define usercopy region in dentry_cache slab cache","commit_ref":null,"pull_url":null,"state":"not-applicable","archived":true,"hash":"4224cdf91ef4a3b2bdcdc808d3d79bc75982de7a","submitter":{"id":10641,"url":"http://patchwork.ozlabs.org/api/people/10641/?format=json","name":"Kees Cook","email":"keescook@chromium.org"},"delegate":{"id":34,"url":"http://patchwork.ozlabs.org/api/users/34/?format=json","username":"davem","first_name":"David","last_name":"Miller","email":"davem@davemloft.net"},"mbox":"http://patchwork.ozlabs.org/project/netdev/patch/1505940337-79069-5-git-send-email-keescook@chromium.org/mbox/","series":[{"id":4231,"url":"http://patchwork.ozlabs.org/api/series/4231/?format=json","web_url":"http://patchwork.ozlabs.org/project/netdev/list/?series=4231","date":"2017-09-20T20:45:22","name":"Hardened usercopy whitelisting","version":3,"mbox":"http://patchwork.ozlabs.org/series/4231/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/816515/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/816515/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"patchwork-incoming@ozlabs.org","Delivered-To":"patchwork-incoming@ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=netdev-owner@vger.kernel.org;\n\treceiver=)","ozlabs.org; dkim=pass (1024-bit key;\n\tunprotected) header.d=chromium.org header.i=@chromium.org\n\theader.b=\"aDvAvQ1S\"; dkim-atps=neutral"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xyByq1cH2z9s8J\n\tfor ;\n\tThu, 21 Sep 2017 07:02:43 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751734AbdITUp7 (ORCPT );\n\tWed, 20 Sep 2017 16:45:59 -0400","from mail-pg0-f52.google.com ([74.125.83.52]:44959 \"EHLO\n\tmail-pg0-f52.google.com\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1751641AbdITUp5 (ORCPT\n\t); Wed, 20 Sep 2017 16:45:57 -0400","by mail-pg0-f52.google.com with SMTP id j16so2342142pga.1\n\tfor ; Wed, 20 Sep 2017 13:45:57 -0700 (PDT)","from www.outflux.net\n\t(173-164-112-133-Oregon.hfc.comcastbusiness.net. [173.164.112.133])\n\tby smtp.gmail.com with ESMTPSA id\n\td186sm8641346pfd.117.2017.09.20.13.45.53\n\t(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);\n\tWed, 20 Sep 2017 13:45:54 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=chromium.org; s=google;\n\th=from:to:cc:subject:date:message-id:in-reply-to:references;\n\tbh=AItuPkxoXP2lQMo2mwVBJC43AWaOTOyiRxkn5bbYjPo=;\n\tb=aDvAvQ1SkZDGOJoKFajT7ucBgLpCSyAEM1GVYDpk9EiYwozOjHJf/Xah/pcvkTbuDE\n\tIrk28pRpF3CruIXTkLfZvixIh9dEbOmQcrBPX50oysuUEfbvgznnH/L7RlM2+TBueAv9\n\t4N85YzvLW1rzVR636P4DvtgGBeojP76B4LWQs=","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to\n\t:references;\n\tbh=AItuPkxoXP2lQMo2mwVBJC43AWaOTOyiRxkn5bbYjPo=;\n\tb=pSTCSDCB17towbfFo0zS8khw6DWOhmWQYsRsruTNKQD1OqEi7EiUo4CBSZPSKPjK3B\n\t/PiwoDUF+hyV5m1AqeksjQdinpJ0rhu8jIY4COWsVIHuONdqk9NQ8Ug/BJqwpt8oKDEh\n\tmbWfP/wxx1f05mGHw2CPfY25ZRCN0B36BRICuGfLtf1yEnaKuQ+r/Rd6nfwfXEg9opB6\n\tDZ4JNPc8v0D58s1q7DqYlZ5dwMPrmpLstWalLY16WQvdeIK9GuLCgbO21tJXfw/jSn+X\n\tkETe285PhOo6Ayvm6d1WbXXB72Agt7m6FhKA89q1FB25lPw0E3ZUN00FjKCv4P2LtJFZ\n\taUGw==","X-Gm-Message-State":"AHPjjUiaSVHb6hwDSxjBXuVaVbXxrx4Hljem7tXXQQTjJv5RcnuVnMUr\n\tqs7+5q+AyfPbMQconuRMCrUadQ==","X-Google-Smtp-Source":"AOwi7QDbpkm9vl3CE7hQ/RcbWT8LJgDOcR21yLCjyMYy4jx0MyRy+XPcYxPO22PAAvc9fdu3cA+7Cw==","X-Received":"by 10.84.252.130 with SMTP id y2mr3175583pll.68.1505940356706;\n\tWed, 20 Sep 2017 13:45:56 -0700 (PDT)","From":"Kees Cook ","To":"linux-kernel@vger.kernel.org","Cc":"Kees Cook , David Windsor ,\n\tAlexander Viro ,\n\tlinux-fsdevel@vger.kernel.org, netdev@vger.kernel.org,\n\tlinux-mm@kvack.org, kernel-hardening@lists.openwall.com","Subject":"[PATCH v3 04/31] dcache: Define usercopy region in dentry_cache\n\tslab cache","Date":"Wed, 20 Sep 2017 13:45:10 -0700","Message-Id":"<1505940337-79069-5-git-send-email-keescook@chromium.org>","X-Mailer":"git-send-email 2.7.4","In-Reply-To":"<1505940337-79069-1-git-send-email-keescook@chromium.org>","References":"<1505940337-79069-1-git-send-email-keescook@chromium.org>","Sender":"netdev-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"netdev@vger.kernel.org"},"content":"From: David Windsor \n\nWhen a dentry name is short enough, it can be stored directly in the\ndentry itself (instead in a separate kmalloc allocation). These dentry\nshort names, stored in struct dentry.d_iname and therefore contained in\nthe dentry_cache slab cache, need to be coped to userspace.\n\ncache object allocation:\n fs/dcache.c:\n __d_alloc(...):\n ...\n dentry = kmem_cache_alloc(dentry_cache, ...);\n ...\n dentry->d_name.name = dentry->d_iname;\n\nexample usage trace:\n filldir+0xb0/0x140\n dcache_readdir+0x82/0x170\n iterate_dir+0x142/0x1b0\n SyS_getdents+0xb5/0x160\n\n fs/readdir.c:\n (called via ctx.actor by dir_emit)\n filldir(..., const char *name, ...):\n ...\n copy_to_user(..., name, namlen)\n\n fs/libfs.c:\n dcache_readdir(...):\n ...\n next = next_positive(dentry, p, 1)\n ...\n dir_emit(..., next->d_name.name, ...)\n\nIn support of usercopy hardening, this patch defines a region in the\ndentry_cache slab cache in which userspace copy operations are allowed.\n\nThis region is known as the slab cache's usercopy region. Slab caches can\nnow check that each copy operation involving cache-managed memory falls\nentirely within the slab's usercopy region.\n\nThis patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY\nwhitelisting code in the last public patch of grsecurity/PaX based on my\nunderstanding of the code. Changes or omissions from the original code are\nmine and don't reflect the original grsecurity/PaX code.\n\nSigned-off-by: David Windsor \n[kees: adjust hunks for kmalloc-specific things moved later]\n[kees: adjust commit log, provide usage trace]\nCc: Alexander Viro \nCc: linux-fsdevel@vger.kernel.org\nSigned-off-by: Kees Cook \n---\n fs/dcache.c | 5 +++--\n 1 file changed, 3 insertions(+), 2 deletions(-)","diff":"diff --git a/fs/dcache.c b/fs/dcache.c\nindex f90141387f01..5f5e7c1fcf4b 100644\n--- a/fs/dcache.c\n+++ b/fs/dcache.c\n@@ -3603,8 +3603,9 @@ static void __init dcache_init(void)\n \t * but it is probably not worth it because of the cache nature\n \t * of the dcache.\n \t */\n-\tdentry_cache = KMEM_CACHE(dentry,\n-\t\tSLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT);\n+\tdentry_cache = KMEM_CACHE_USERCOPY(dentry,\n+\t\tSLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT,\n+\t\td_iname);\n \n \t/* Hash may have been set up in dcache_init_early */\n \tif (!hashdist)\n","prefixes":["v3","04/31"]}