From mboxrd@z Thu Jan 1 00:00:00 1970 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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 autolearn=unavailable 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 D6EFBC433DB for ; Mon, 15 Feb 2021 16:42:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A67C864E0F for ; Mon, 15 Feb 2021 16:42:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230142AbhBOQmS (ORCPT ); Mon, 15 Feb 2021 11:42:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:50360 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231567AbhBOPiB (ORCPT ); Mon, 15 Feb 2021 10:38:01 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 51F3C64EE9; Mon, 15 Feb 2021 15:33:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613403230; bh=ft4G97VhIjJwaES8UFkwK1Ab7kaT0oqcang245BltCQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xF0EwvTAQJvQc7BzyRaxUdpqfOvdHZX5yrtLZ262gP1z5C4SmpfyASuI+xgUWw9ym hfHpFMhI034FzW0Rx0XbVM5ElKQu5SrlAGsXzV+veuSDcGAWmyZ9NuR2AlSSsYUg18 Fq1Kp0RAXqDqgFbVJZDq4OEQObAplcqY5wsGaQJc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Will Deacon , Russell King , Sasha Levin Subject: [PATCH 5.10 041/104] ARM: ensure the signal page contains defined contents Date: Mon, 15 Feb 2021 16:26:54 +0100 Message-Id: <20210215152720.801524308@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210215152719.459796636@linuxfoundation.org> References: <20210215152719.459796636@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Russell King [ Upstream commit 9c698bff66ab4914bb3d71da7dc6112519bde23e ] Ensure that the signal page contains our poison instruction to increase the protection against ROP attacks and also contains well defined contents. Acked-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Sasha Levin --- arch/arm/kernel/signal.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 585edbfccf6df..2f81d3af5f9af 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -693,18 +693,20 @@ struct page *get_signal_page(void) addr = page_address(page); + /* Poison the entire page */ + memset32(addr, __opcode_to_mem_arm(0xe7fddef1), + PAGE_SIZE / sizeof(u32)); + /* Give the signal return code some randomness */ offset = 0x200 + (get_random_int() & 0x7fc); signal_return_offset = offset; - /* - * Copy signal return handlers into the vector page, and - * set sigreturn to be a pointer to these. - */ + /* Copy signal return handlers into the page */ memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes)); - ptr = (unsigned long)addr + offset; - flush_icache_range(ptr, ptr + sizeof(sigreturn_codes)); + /* Flush out all instructions in this page */ + ptr = (unsigned long)addr; + flush_icache_range(ptr, ptr + PAGE_SIZE); return page; } -- 2.27.0