From patchwork Thu Apr 8 18:28:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12192193 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 038BBC43470 for ; Thu, 8 Apr 2021 18:29:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D37CA61158 for ; Thu, 8 Apr 2021 18:29:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233017AbhDHS36 (ORCPT ); Thu, 8 Apr 2021 14:29:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232918AbhDHS3j (ORCPT ); Thu, 8 Apr 2021 14:29:39 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DAECC0613A8 for ; Thu, 8 Apr 2021 11:29:05 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id n67so2873231ybf.11 for ; Thu, 08 Apr 2021 11:29:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=A4KMkUZrl4YbLTqlF2GjjNGTYuxFr+/F8S0sGB79SBc=; b=rt9fOxKnB9y0igHfYBfQLlswurHVd9akIm8mQ7xCsufNWiBYdR3JhCpYM7Uax/eLvb Ihhz4rq6HcyX7REf0u2fqx7LVp4ukkmU+QC5NvoPcxJetx0GLnWLloqncFHy9GmoYMBn XjIhO8wNOL3YaZSw+9n6f8hcXwGNa5EVXVYOv+TLwmMSwMQDUKpz6OfnrIlesqFMkgkR XwLL5SN+XXLMayXhC5sCImEanWSuJTwkFWqMibje/hh2cGiFwv4rge6/fnMF/5m4/W6v 2KS84+T3ETJUQYWmacNH46sk/sKcVZ9rguitgtGIPddtwdEI5YDOujUYGBTToDSb8o4O GYVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=A4KMkUZrl4YbLTqlF2GjjNGTYuxFr+/F8S0sGB79SBc=; b=QmYUebTAh5pYjihrd6M5XxouBd71nBZpvgDwK/p4IGtYljL71k5r3TyS4Ub5A2cRMB v8W/RB37RIMo8JEXDPFxUWXnLnPT5OMc0fYHzkWEsFJgzcQAQvxIURJBPSfN0Dc4pYh5 GDLLqfE4fn01alz3E91DH68HSh0LuCAy4cFRVgYrFKJ1thOlxIavXWorDSTQeeqL8Z5E QagtIkg40pj4Nja9QCqBedj6nxk2V93DLwVrVh5SWn6U3mJbwIwMfmRt5ZGHVZ3yQQX5 Qg6V1tTL2xuAH6P7mr9DaCtPLZy7gwdMoM2bhYauB66rE9e5eBCLiYET6X8X9iGWVRMr /fhg== X-Gm-Message-State: AOAM530u5rLI16C9+LTQ84MC6zunbdQ0UkMMPexTaNEfcCS9aeANv/mQ pzmYMDfc9KIk6rnIxFSxDo35A+CUI4Hyw+Ishj0= X-Google-Smtp-Source: ABdhPJy9XDHY4+uyYXn6KtdLMb9MXbOaRaW45MMiG7dZpwvMKLXKIxABytCBmfYEFzzpAYPpLEY0MfZ524rYOheFYP8= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:3560:8505:40a2:e021]) (user=samitolvanen job=sendgmr) by 2002:a25:ea44:: with SMTP id o4mr9706249ybe.506.1617906544646; Thu, 08 Apr 2021 11:29:04 -0700 (PDT) Date: Thu, 8 Apr 2021 11:28:35 -0700 In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com> Message-Id: <20210408182843.1754385-11-samitolvanen@google.com> Mime-Version: 1.0 References: <20210408182843.1754385-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.1.295.g9ea45b61b8-goog Subject: [PATCH v6 10/18] lkdtm: use function_nocfi From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org To ensure we take the actual address of a function in kernel text, use function_nocfi. Otherwise, with CONFIG_CFI_CLANG, the compiler replaces the address with a pointer to the CFI jump table, which is actually in the module when compiled with CONFIG_LKDTM=m. Signed-off-by: Sami Tolvanen Acked-by: Kees Cook Tested-by: Nathan Chancellor --- drivers/misc/lkdtm/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index 109e8d4302c1..15d220ef35a5 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -314,7 +314,7 @@ void lkdtm_USERCOPY_KERNEL(void) pr_info("attempting bad copy_to_user from kernel text: %px\n", vm_mmap); - if (copy_to_user((void __user *)user_addr, vm_mmap, + if (copy_to_user((void __user *)user_addr, function_nocfi(vm_mmap), unconst + PAGE_SIZE)) { pr_warn("copy_to_user failed, but lacked Oops\n"); goto free_user;