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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 42804C35671 for ; Sun, 23 Feb 2020 02:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 14E0C20659 for ; Sun, 23 Feb 2020 02:37:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582425423; bh=DlmwdQDlQ9+dL/5tK1OOSNXQg1vVFb3H4mk64k4cgLY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FRz1T7GEd4xdDMeVVm3AIP4NM9UdN7hY9+q+bsJGCKpPB65/PtftagiimXDfyNq8b 54y3hcQcbZVz2IWW6R4YeDIa10G9zE94GXUD5F7TwG8THaaI3X97hdec3f2L0RnbZ9 KppwWcDQaySXcyDyxszvmEkBaKQA2eMKgI4wvX4E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727758AbgBWCVu (ORCPT ); Sat, 22 Feb 2020 21:21:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:50090 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727584AbgBWCVk (ORCPT ); Sat, 22 Feb 2020 21:21:40 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F23E3214DB; Sun, 23 Feb 2020 02:21:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582424499; bh=DlmwdQDlQ9+dL/5tK1OOSNXQg1vVFb3H4mk64k4cgLY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d/wiWVxhT2D5Kpk8Pxkc8zwYBZaZsKY9DMopvXnX6xKznxw9/g85+6Cx9L0iChyge +lcsqQz0aJlMCABR4yJCQNF8XGeNc2Vj/K5Umj2zGCyWxuyL/3En45dzbwZOQM7vqD agb6TOXBzGKuv6TFei//1+/txFRQE8GKGNHs75V8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Suren Baghdasaryan , Peter Zijlstra , Ingo Molnar , Johannes Weiner , Sasha Levin Subject: [PATCH AUTOSEL 5.5 16/58] sched/psi: Fix OOB write when writing 0 bytes to PSI files Date: Sat, 22 Feb 2020 21:20:37 -0500 Message-Id: <20200223022119.707-16-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200223022119.707-1-sashal@kernel.org> References: <20200223022119.707-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Suren Baghdasaryan [ Upstream commit 6fcca0fa48118e6d63733eb4644c6cd880c15b8f ] Issuing write() with count parameter set to 0 on any file under /proc/pressure/ will cause an OOB write because of the access to buf[buf_size-1] when NUL-termination is performed. Fix this by checking for buf_size to be non-zero. Signed-off-by: Suren Baghdasaryan Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Acked-by: Johannes Weiner Link: https://lkml.kernel.org/r/20200203212216.7076-1-surenb@google.com Signed-off-by: Sasha Levin --- kernel/sched/psi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c index ce8f6748678a2..9154e745f0978 100644 --- a/kernel/sched/psi.c +++ b/kernel/sched/psi.c @@ -1199,6 +1199,9 @@ static ssize_t psi_write(struct file *file, const char __user *user_buf, if (static_branch_likely(&psi_disabled)) return -EOPNOTSUPP; + if (!nbytes) + return -EINVAL; + buf_size = min(nbytes, sizeof(buf)); if (copy_from_user(buf, user_buf, buf_size)) return -EFAULT; -- 2.20.1