From patchwork Wed Aug 29 22:59:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Edgecombe, Rick P" X-Patchwork-Id: 10581043 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D9EF51390 for ; Wed, 29 Aug 2018 23:00:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CBE072B177 for ; Wed, 29 Aug 2018 23:00:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BE18C2B174; Wed, 29 Aug 2018 23:00:13 +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=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED 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 CEE6D2B174 for ; Wed, 29 Aug 2018 23:00:12 +0000 (UTC) Received: (qmail 13342 invoked by uid 550); 29 Aug 2018 22:59:55 -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 13324 invoked from network); 29 Aug 2018 22:59:55 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,305,1531810800"; d="scan'208";a="85609392" From: Rick Edgecombe To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, daniel@iogearbox.net, jannh@google.com, keescook@chromium.org Cc: kristen@linux.intel.com, dave.hansen@intel.com, arjan@linux.intel.com, Rick Edgecombe Subject: [PATCH v4 0/3] KASLR feature to randomize each loadable module Date: Wed, 29 Aug 2018 15:59:36 -0700 Message-Id: <1535583579-6138-1-git-send-email-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.7.4 X-Virus-Scanned: ClamAV using ClamSMTP Hi, This is v4 of the "KASLR feature to randomize each loadable module" patchset. The purpose is to increase the randomization and also to make the modules randomized in relation to each other instead of just the base, so that if one module leaks the location of the others can't be inferred. It is enabled for x86_64 for now. V4 is a few small fixes. I humbly think this is in pretty good shape at this point, unless anyone has any comments. The only other big change I was considering was moving the new randomization algorithm into vmalloc so it could be re-used for other architectures or possibly other vmalloc usages. A few words on how this was tested - As previously mentioned, the entropy estimates were done using extracted module text sizes from the in-tree modules. These were also used to run 100,000's of simulated module allocations by calling module_alloc from a test module, including testing until allocation failure. The simulations kept track of every allocation address to make sure there were no collisions, and verified memory was actually mapped. In addition the __vmalloc_node_try_addr function has a suite of unit tests that verify for a bunch of edge cases that it: - Allows for allocations when it should - Reports the right error code if it collides with a lazy-free area or real allocation - Verifies it frees a lazy free area when it should These synthetic tests were also how the performance metrics were gathered. Changes for V4: - Fix issue caused by KASAN, kmemleak being provided different allocation lengths (padding). - Avoid kmalloc until sure its needed in __vmalloc_node_try_addr. - Fix for debug file hang when the last VA is a lazy purge area - Fixed issues reported by 0-day build system. Changes for V3: - Code cleanup based on internal feedback. (thanks to Dave Hansen and Andriy Shevchenko) - Slight refactor of existing algorithm to more cleanly live along side new one. - BPF synthetic benchmark Changes for V2: - New implementation of __vmalloc_node_try_addr based on the __vmalloc_node_range implementation, that only flushes TLB when needed. - Modified module loading algorithm to try to reduce the TLB flushes further. - Increase "random area" tries in order to increase the number of modules that can get high randomness. - Increase "random area" size to 2/3 of module area in order to increase the number of modules that can get high randomness. - Fix for 0day failures on other architectures. - Fix for wrong debugfs permissions. (thanks to Jann Horn) - Spelling fix. (thanks to Jann Horn) - Data on module_alloc performance and TLB flushes. (brought up by Kees Cook and Jann Horn) - Data on memory usage. (suggested by Jann) Rick Edgecombe (3): vmalloc: Add __vmalloc_node_try_addr function x86/modules: Increase randomization for modules vmalloc: Add debugfs modfraginfo arch/x86/include/asm/pgtable_64_types.h | 7 + arch/x86/kernel/module.c | 165 ++++++++++++++++--- include/linux/vmalloc.h | 3 + mm/vmalloc.c | 279 +++++++++++++++++++++++++++++++- 4 files changed, 429 insertions(+), 25 deletions(-)