From patchwork Tue Mar 24 20:32:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 11456473 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2D6E1913 for ; Tue, 24 Mar 2020 20:33:58 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E65C52080C for ; Tue, 24 Mar 2020 20:33:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UW5sT42F"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="S9Srk3vt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E65C52080C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lBwmX6m8RZxjD1zr1ZU86KFvj4Yx4LxjWtVsHo9i6h0=; b=UW5sT42FjisypD nTA9TwobqADBgiCRzisB/k4EnoElrAs1lnjijns0xSqIyzxx85PWpzPwm9tfikgzeOAdzhEtKIP45 OUPXoE5+6hBczZbypIQEOJpYwA/E6hCISC9wl/oIhEDlPC0U8lxpmY9X41jcRLxfUhQtNqfGHBU7Q klX72t9RVccL8cVEtyVP3msqSV6RbnaeI2NEuj9N/cNpu4solwxVTw6QS1vIKzrCGubVf+Fy8fbPp 9CjeGuD9Jjcek0dQVeDVk0JE8zYcebMzquRvlalQEqxJuSmROIs7hRIw1z7TjC7AgitZK8A/tXypu xt9WsHnUyZedUMhRzesg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jGqFH-0003Hw-1O; Tue, 24 Mar 2020 20:33:55 +0000 Received: from mail-pl1-x642.google.com ([2607:f8b0:4864:20::642]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jGqE8-0001xW-3i for linux-arm-kernel@lists.infradead.org; Tue, 24 Mar 2020 20:32:45 +0000 Received: by mail-pl1-x642.google.com with SMTP id w3so7900893plz.5 for ; Tue, 24 Mar 2020 13:32:43 -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 :mime-version:content-transfer-encoding; bh=c3b1sjWFJGWk+HhbHvBn4evu301M7fqA/kMQ4pyC4tI=; b=S9Srk3vtm/u5AWxb5Lq0VLBe/+/+CUvcc/nWuriifzbcDxo3ZwBkLe8Zpl+BamGg/O HO1v1zWZwiU7plLhdxR37s1Jaqc0uJSA8G7tsY4VxqWCO/G2fiHTxNvERagnEIgId99M jOOdb0wJUrZaXGZR5SVzv7rR8cyPHnbBh6gDc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=c3b1sjWFJGWk+HhbHvBn4evu301M7fqA/kMQ4pyC4tI=; b=J+TFYYZVpYtdpHKV+7bYUJLrNRgCAcJs3XJWmNprnnkmQrckHKd3CMpfQsGuAcXEJf 7f8VovNlzu9p5s+1L3kqhEfNv2IgOPKfX2OeKRBltwpI2OnAQCNrPcuDn0asur00CCW7 sWHuGkJwbMYmjZ/K2wyvLpF3844cnhmmimEpjLiAwO79zjXJ21GQTg+oPth1waI30omt Y6Ovr88Y4ExaOpUKQV0yh5LIpYVsBQQG3NuOcn1EdYYer+NtZUgf/WMhdTd9RJ4T56/u e165RD8RFrfHw/Bg9kNg+0fP/a6sMgIvlUzlKUmBnRZaXlsWRj9a5dtnHeXzBuwRwdpt ujIQ== X-Gm-Message-State: ANhLgQ2meKgQS2P7GEbYsZa6rpz5o9DHPsDwyExeKJddf6BJm6fsm+Pn Uhhnr+89CkrXdZLOQXXEjblJZw== X-Google-Smtp-Source: ADFU+vtXBHEgdg26RkMBmCkSMYW4AGLyko9MzjPWEETXma0en8jpa6fm5D16S9175yT7TTEUnSU+xQ== X-Received: by 2002:a17:90a:1911:: with SMTP id 17mr205762pjg.65.1585081963230; Tue, 24 Mar 2020 13:32:43 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id v26sm3813241pfn.51.2020.03.24.13.32.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Mar 2020 13:32:41 -0700 (PDT) From: Kees Cook To: Thomas Gleixner Subject: [PATCH v2 5/5] arm64: entry: Enable random_kstack_offset support Date: Tue, 24 Mar 2020 13:32:31 -0700 Message-Id: <20200324203231.64324-6-keescook@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200324203231.64324-1-keescook@chromium.org> References: <20200324203231.64324-1-keescook@chromium.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200324_133244_192085_1766C480 X-CRM114-Status: GOOD ( 14.08 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.3 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:642 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Kees Cook , Jann Horn , Ard Biesheuvel , Peter Zijlstra , Catalin Marinas , x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Andy Lutomirski , kernel-hardening@lists.openwall.com, "Perla, Enrico" , Will Deacon , Elena Reshetova Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Allow for a randomized stack offset on a per-syscall basis, with roughly 5 bits of entropy. Signed-off-by: Kees Cook Acked-by: Mark Rutland Acked-by: Will Deacon --- arch/arm64/Kconfig | 1 + arch/arm64/kernel/syscall.c | 10 ++++++++++ 2 files changed, 11 insertions(+) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 0b30e884e088..4d5aa4959f72 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -127,6 +127,7 @@ config ARM64 select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_PREL32_RELOCATIONS + select HAVE_ARCH_RANDOMIZE_KSTACK_OFFSET select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_STACKLEAK select HAVE_ARCH_THREAD_STRUCT_WHITELIST diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c index a12c0c88d345..238dbd753b44 100644 --- a/arch/arm64/kernel/syscall.c +++ b/arch/arm64/kernel/syscall.c @@ -5,6 +5,7 @@ #include #include #include +#include #include #include @@ -42,6 +43,8 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, { long ret; + add_random_kstack_offset(); + if (scno < sc_nr) { syscall_fn_t syscall_fn; syscall_fn = syscall_table[array_index_nospec(scno, sc_nr)]; @@ -51,6 +54,13 @@ static void invoke_syscall(struct pt_regs *regs, unsigned int scno, } regs->regs[0] = ret; + + /* + * Since the compiler chooses a 4 bit alignment for the stack, + * let's save one additional bit (9 total), which gets us up + * near 5 bits of entropy. + */ + choose_random_kstack_offset(get_random_int() & 0x1FF); } static inline bool has_syscall_work(unsigned long flags)