From patchwork Fri Jul 15 21:44:24 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9232801 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 1919560865 for ; Fri, 15 Jul 2016 21:46:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0B81926D08 for ; Fri, 15 Jul 2016 21:46:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F353D27BF9; Fri, 15 Jul 2016 21:46:02 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 D7E1226D08 for ; Fri, 15 Jul 2016 21:46:01 +0000 (UTC) Received: (qmail 17952 invoked by uid 550); 15 Jul 2016 21:44:54 -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: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 17751 invoked from network); 15 Jul 2016 21:44:48 -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=O1WrJK+bkVI7D0upgvjY1waXnYQIGeUKeqmx7i8hvGo=; b=ebeURLJHVzcOyaNh6oZ5tqu3ptTsucTXasETgtXjRtnNMBAlVmiE8Iy5gIxPno1BKL fIlMn1Erl/vrY2xFaf0HP5Xg8No9ibvW/OZzQ+8mJlAAwM0EvUY+RKu2xZiaqNuAuQGp tbBFGsO2SsQcowmdfiES6EeAntilJVRL3Tilo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=O1WrJK+bkVI7D0upgvjY1waXnYQIGeUKeqmx7i8hvGo=; b=Zh77qWSezaQG6sTJZBGhwwN5y11Jqwo8Qx1HM0Gl68lyRLZeRZgMI4Ceo8awuVOqVZ WZxI+smhEsBQl2qc2Vd/hLZ7auOnP7XngRY2neP0uoQJxxbIaLvyfwr4UL0KgmBPIFez GNNVTNbZGn6MePJnjdaEgK5Pi6cDzXhr5GTZGbVwk99SAjpqkCTJ+72bBlUZ9sNxhUhS OFZdFNOcUC2uE8ixIDND2kzCpDogQlX4M067YZxOys8GOfn0AMJ843h9IkUWB8+tz6NH RLyyvlxHYKI/JI7dJQINyArTWYFXufDnYmTv04LtwBNFuUp5ClICHKxDAiEFpUvnp7q8 WFog== X-Gm-Message-State: ALyK8tI5MY9eL/0tLskQ2lPrsDHkH3GCkBeVB3cbkKgmGC4E6/nyGH5ikfrbYO5EzStNl7Hz X-Received: by 10.67.8.69 with SMTP id di5mr35099016pad.123.1468619077072; Fri, 15 Jul 2016 14:44:37 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , Balbir Singh , Daniel Micay , Josh Poimboeuf , Rik van Riel , Casey Schaufler , PaX Team , Brad Spengler , Russell King , Catalin Marinas , Will Deacon , Ard Biesheuvel , Benjamin Herrenschmidt , Michael Ellerman , Tony Luck , Fenghua Yu , "David S. Miller" , x86@kernel.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Andy Lutomirski , Borislav Petkov , Mathias Krause , Jan Kara , Vitaly Wool , Andrea Arcangeli , Dmitry Vyukov , Laura Abbott , linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Date: Fri, 15 Jul 2016 14:44:24 -0700 Message-Id: <1468619065-3222-11-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1468619065-3222-1-git-send-email-keescook@chromium.org> References: <1468619065-3222-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH v3 10/11] mm: SLAB hardened usercopy support X-Virus-Scanned: ClamAV using ClamSMTP Under CONFIG_HARDENED_USERCOPY, this adds object size checking to the SLAB allocator to catch any copies that may span objects. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook Tested-By: Valdis Kletnieks --- init/Kconfig | 1 + mm/slab.c | 30 ++++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/init/Kconfig b/init/Kconfig index f755a602d4a1..798c2020ee7c 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1757,6 +1757,7 @@ choice config SLAB bool "SLAB" + select HAVE_HARDENED_USERCOPY_ALLOCATOR help The regular slab allocator that is established and known to work well in all environments. It organizes cache hot objects in diff --git a/mm/slab.c b/mm/slab.c index cc8bbc1e6bc9..5e2d5f349aca 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4477,6 +4477,36 @@ static int __init slab_proc_init(void) module_init(slab_proc_init); #endif +#ifdef CONFIG_HARDENED_USERCOPY +/* + * Rejects objects that are incorrectly sized. + * + * Returns NULL if check passes, otherwise const char * to name of cache + * to indicate an error. + */ +const char *__check_heap_object(const void *ptr, unsigned long n, + struct page *page) +{ + struct kmem_cache *cachep; + unsigned int objnr; + unsigned long offset; + + /* Find and validate object. */ + cachep = page->slab_cache; + objnr = obj_to_index(cachep, page, (void *)ptr); + BUG_ON(objnr >= cachep->num); + + /* Find offset within object. */ + offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); + + /* Allow address range falling entirely within object size. */ + if (offset <= cachep->object_size && n <= cachep->object_size - offset) + return NULL; + + return cachep->name; +} +#endif /* CONFIG_HARDENED_USERCOPY */ + /** * ksize - get the actual amount of memory allocated for a given object * @objp: Pointer to the object