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=-20.2 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 8E302C433EF for ; Mon, 20 Sep 2021 18:24:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 70FD961AD0 for ; Mon, 20 Sep 2021 18:24:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346709AbhITSZf (ORCPT ); Mon, 20 Sep 2021 14:25:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:40990 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344009AbhITSS5 (ORCPT ); Mon, 20 Sep 2021 14:18:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id A6DF9632AB; Mon, 20 Sep 2021 17:23:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632158593; bh=nFgCtX4TUZ4Is7S8X4Jxx5TU8pPnTOTTKO3PHLhqnzU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RklfHSS0yBz1QEEi3ZNwrA9Lh9/qWxkf0TOOJjLMee1nR5ai/yxYzNpIwC2/sZw5t u7Z1bozKHIv9YIgoIqKS+rXhVRrpMUUzGzfyAk8hTWFEyP7vRG50ko/xSCGhaPLTL+ kbE+nQVZnXb8fkcC6p4aBiFRnOi3hCGfjHz1i3yo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Brown , Catalin Marinas Subject: [PATCH 5.4 195/260] arm64/sve: Use correct size when reinitialising SVE state Date: Mon, 20 Sep 2021 18:43:33 +0200 Message-Id: <20210920163937.737954530@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210920163931.123590023@linuxfoundation.org> References: <20210920163931.123590023@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: Mark Brown commit e35ac9d0b56e9efefaeeb84b635ea26c2839ea86 upstream. When we need a buffer for SVE register state we call sve_alloc() to make sure that one is there. In order to avoid repeated allocations and frees we keep the buffer around unless we change vector length and just memset() it to ensure a clean register state. The function that deals with this takes the task to operate on as an argument, however in the case where we do a memset() we initialise using the SVE state size for the current task rather than the task passed as an argument. This is only an issue in the case where we are setting the register state for a task via ptrace and the task being configured has a different vector length to the task tracing it. In the case where the buffer is larger in the traced process we will leak old state from the traced process to itself, in the case where the buffer is smaller in the traced process we will overflow the buffer and corrupt memory. Fixes: bc0ee4760364 ("arm64/sve: Core task context handling") Cc: # 4.15.x Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20210909165356.10675-1-broonie@kernel.org Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/fpsimd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -498,7 +498,7 @@ size_t sve_state_size(struct task_struct void sve_alloc(struct task_struct *task) { if (task->thread.sve_state) { - memset(task->thread.sve_state, 0, sve_state_size(current)); + memset(task->thread.sve_state, 0, sve_state_size(task)); return; }