From patchwork Wed Jul 20 20:27:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9240493 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 9246B6077C for ; Wed, 20 Jul 2016 20:29:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8463A27C39 for ; Wed, 20 Jul 2016 20:29:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7890627D5E; Wed, 20 Jul 2016 20:29:02 +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 91F8A27C39 for ; Wed, 20 Jul 2016 20:29:01 +0000 (UTC) Received: (qmail 9805 invoked by uid 550); 20 Jul 2016 20:27:41 -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 9575 invoked from network); 20 Jul 2016 20:27:35 -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=0MPQsN6aA0t9gZEW0aiBDC5li+z+8lKE/uD//oHccL0=; b=bzsIK4L5QScRZz1IX6GykayiEz95aXyj6s2cIfGk/t4kfqinneXmv0+GFnFCHKhOh1 hpGt7JPZglMDvAMc+CubvA0h3WKakAzyzU08uNx2vw6G32NzwL/kwxLCBjSQ3SCC7Q0Y BHurbCM5no6xluIIQ5tA35lIIzRWaww8wkoQo= 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=0MPQsN6aA0t9gZEW0aiBDC5li+z+8lKE/uD//oHccL0=; b=lw/CKsmIxeCBUkZ8YSapykbbEzf7fhtQbIjJWq/RpoXSb3ayTVntXvFGllKiYmwQsr xsjjPOakCNJEzrDliaU3evP7/7TTjZsOejtN/O6C0WbsT3jdVGGrSPTkvwogV2F2nevt knhY2lW248kuCrTZIPv1J/IoPPDRm633rry6zPdGVji7xV7/TDyRGirdvKlTjCGn0roS EZYflIwM7d73XVFbRr+Yg//ZuG7XYjDKnypy/WUNG/r31zyAM8orTqY1+DYyAUniWOLZ GSAB3XnHyxxQWR3k5ygSbysHbA3b51mwRTpV8l8D/I0dlVf7cn8Wt2GOeYaklEr/Li0w mbrg== X-Gm-Message-State: ALyK8tIP8KElEbpwPbsr4B0SwXfxMA6ibSBo/pjQEJRbvZWPHBHJb+DSM4jcKPbjFNqkclqV X-Received: by 10.66.193.163 with SMTP id hp3mr72154780pac.73.1469046443490; Wed, 20 Jul 2016 13:27:23 -0700 (PDT) From: Kees Cook To: kernel-hardening@lists.openwall.com Cc: Kees Cook , Laura Abbott , 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 , 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, linux-kernel@vger.kernel.org Date: Wed, 20 Jul 2016 13:27:07 -0700 Message-Id: <1469046427-12696-13-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1469046427-12696-1-git-send-email-keescook@chromium.org> References: <1469046427-12696-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH v4 12/12] mm: SLUB hardened usercopy support X-Virus-Scanned: ClamAV using ClamSMTP Under CONFIG_HARDENED_USERCOPY, this adds object size checking to the SLUB allocator to catch any copies that may span objects. Includes a redzone handling fix discovered by Michael Ellerman. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook Tested-by: Michael Ellerman --- init/Kconfig | 1 + mm/slub.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/init/Kconfig b/init/Kconfig index 798c2020ee7c..1c4711819dfd 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1765,6 +1765,7 @@ config SLAB config SLUB bool "SLUB (Unqueued Allocator)" + select HAVE_HARDENED_USERCOPY_ALLOCATOR help SLUB is a slab allocator that minimizes cache line usage instead of managing queues of cached objects (SLAB approach). diff --git a/mm/slub.c b/mm/slub.c index 825ff4505336..7dee3d9a5843 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3614,6 +3614,42 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) EXPORT_SYMBOL(__kmalloc_node); #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 *s; + unsigned long offset; + size_t object_size; + + /* Find object and usable object size. */ + s = page->slab_cache; + object_size = slab_ksize(s); + + /* Find offset within object. */ + offset = (ptr - page_address(page)) % s->size; + + /* Adjust for redzone and reject if within the redzone. */ + if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) { + if (offset < s->red_left_pad) + return s->name; + offset -= s->red_left_pad; + } + + /* Allow address range falling entirely within object size. */ + if (offset <= object_size && n <= object_size - offset) + return NULL; + + return s->name; +} +#endif /* CONFIG_HARDENED_USERCOPY */ + static size_t __ksize(const void *object) { struct page *page;