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: 9240521 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 1440D6077C for ; Wed, 20 Jul 2016 20:31:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0586227C26 for ; Wed, 20 Jul 2016 20:31:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EE0FB27D4D; Wed, 20 Jul 2016 20:31:48 +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=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A44E727C26 for ; Wed, 20 Jul 2016 20:31:48 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bPy8P-0002i7-EQ; Wed, 20 Jul 2016 20:30:25 +0000 Received: from mail-pa0-x234.google.com ([2607:f8b0:400e:c03::234]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bPy5o-0007lh-8c for linux-arm-kernel@lists.infradead.org; Wed, 20 Jul 2016 20:27:47 +0000 Received: by mail-pa0-x234.google.com with SMTP id ks6so21478098pab.0 for ; Wed, 20 Jul 2016 13:27:23 -0700 (PDT) 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=imODsVFN3HMxj9HMEoqM6v93PtBJvEpSn7Wxfz4DRSrj+j5v2lE04Y3yNmp5WYNNTi rN6Bmy03/KIQw5h/+kz/SChdj5Wfzeck1Lp+UuEVnR6MTpgJDKio+kwLe/xj7V6C2cUR eDcIOfnQB/R9BHwDBtCJFTA1tERFh+MBZx/OjUueLeUOM2TZTlCOFBTo2y04dH9ralLd rTRNzkVrMo4fUgioZ9tFu2GWixdbfU9zttMM53fMHy4CIxYQATfDwkdppgWzpbAbB3Kv y/g2ZU/PkJWnOo0ZLQnCa2N8DJO78VO+AteVZmNp3g+J94ksAlsuLxitnLgI/VCr20fR NNgw== X-Gm-Message-State: ALyK8tLCsoXuwR/26yUUMF7pjz7mzJExkBs+l+RdAOoKF3SEPZxZjvl8dTPhAOA/xghowYze X-Received: by 10.66.193.163 with SMTP id hp3mr72154780pac.73.1469046443490; Wed, 20 Jul 2016 13:27:23 -0700 (PDT) Received: from www.outflux.net ([2002:ada4:7085:0:ae16:2dff:fe07:4fb6]) by smtp.gmail.com with ESMTPSA id m24sm6607617pfi.34.2016.07.20.13.27.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Jul 2016 13:27:22 -0700 (PDT) From: Kees Cook To: kernel-hardening@lists.openwall.com Subject: [PATCH v4 12/12] mm: SLUB hardened usercopy support 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160720_132744_650373_63C96BF7 X-CRM114-Status: GOOD ( 14.67 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jan Kara , Benjamin Herrenschmidt , Balbir Singh , Will Deacon , linux-mm@kvack.org, sparclinux@vger.kernel.org, linux-ia64@vger.kernel.org, Christoph Lameter , Andrea Arcangeli , linux-arch@vger.kernel.org, Michael Ellerman , x86@kernel.org, Russell King , linux-arm-kernel@lists.infradead.org, Catalin Marinas , PaX Team , Borislav Petkov , Mathias Krause , Fenghua Yu , Rik van Riel , Kees Cook , Vitaly Wool , David Rientjes , Tony Luck , Andy Lutomirski , Josh Poimboeuf , Andrew Morton , Dmitry Vyukov , Laura Abbott , Brad Spengler , Ard Biesheuvel , linux-kernel@vger.kernel.org, Pekka Enberg , Daniel Micay , Casey Schaufler , Joonsoo Kim , linuxppc-dev@lists.ozlabs.org, "David S. Miller" MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org 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;