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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4986ECCFA13 for ; Thu, 30 Apr 2026 10:37:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:Cc:To:From: Subject:Message-ID:Mime-Version:Date:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=CE7ryhQPSrXB5CO15AITdkHOu/b63A3t1puDBO48YFY=; b=ShJ3v4jvMpNUAILNURkMB9xdZa z2eGoJf0pNojz+1ryWleGm1bFYf60GNsrGeWLqQSNbN7fNrGS0X2fTfIugvEHg2NuuLTkQpBUqjWf o+BijywEVdWXuZqCD2wUtmRQA7JzVtMhPDal0NdwDbeZmXIFTVyQOcnmVdmoR+3uhegdQn6tvDC/S yXb94IP55wnkoWuKvnxDhIhUmenggCKk+nO3Owe+7fETcLV/7Sies5hhckej4ybjFNZcY9rkL6Vub LOXgsWKAv9khXSZ633Eo4+1sgWWaTTvK4ToIa2hgp5NePDzcx8tu3vmdYPtkpSauGpKnRxjwcZWaO WatjI1pA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wIOm1-00000005D6u-4Aoc; Thu, 30 Apr 2026 10:37:38 +0000 Received: from mail-wr1-x44a.google.com ([2a00:1450:4864:20::44a]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wIOlz-00000005D5n-3nhc for linux-arm-kernel@lists.infradead.org; Thu, 30 Apr 2026 10:37:37 +0000 Received: by mail-wr1-x44a.google.com with SMTP id ffacd0b85a97d-43d03065782so450305f8f.0 for ; Thu, 30 Apr 2026 03:37:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1777545453; x=1778150253; darn=lists.infradead.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=CE7ryhQPSrXB5CO15AITdkHOu/b63A3t1puDBO48YFY=; b=D4XdDSdydLNjw779SokUUeQ5++d9+8gy+kY+E4RwzOH9dHcymJ3D2gJZf8qY4jN6Dp 97hYw2GBMXbv+8oQtoWnEPNIPSEnKg4ov58zqvdSGydEXhBc353mZn585kwOuQHoLcXN ND2Rkk43fAzyZz/WoFWyjWiRcMvvK9TznPR+xihLnAdR+/EcSTVwTGhQUK4Wz7g8lXs/ jRwgwCaeWkPp9iRXPFnq6WdyyMhDk5iSCFbIamWsDtuKURxH1tOT05izD0Aa7WXWvtrQ V83RHbIE0Z1Rrpi5E/jHYhV6HQNZZsCCrTYcanVRLHFJXnUIaRfjg5S+Of+z314rf1IK 5woA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777545453; x=1778150253; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CE7ryhQPSrXB5CO15AITdkHOu/b63A3t1puDBO48YFY=; b=aBHp/dmZdOemjfma7Cediqezud7DkEc6Cjs7E+3Z9eI3Avi+KoJnNNkHpQmTOg1UII LxB1Xg53V+jZXFL89OcI3FMe5iLcq4h1BXF3v/yDfcXMI5VfuppGOGsOHJgfQQOwCEcm Aa4pOk9iwt1/OGRM1o9sVHNi049NKDy9RhPeQv+z3lq5CXp/OfYXo9HuCl3vrimNhnB3 +ILu1xTEbqww4nAa+Dm5lPiUDkstLqDkTY4Kk7bE1ThFy3i0ncdp/0i4toJnZbaZqhWY ypjraIantDkEFRK6Wcsmo1sFW53E8kfWeznPqZEMOYGuG8ECPw65si6Melzm2xosHfoN t5/A== X-Gm-Message-State: AOJu0YywUo+wVlcql1bCTG29eEI8+g6aXJr/3lzJ0exMd1JunRBN2EdM /iprTTT+FD3wmASHDLEAaxkZR56LAVW6JK+0Jx+i6yTXHrlFrMZeVMQ7CtnGSMS6F+dCkbid+pZ SlbkzGIYflgBLKEbaHLGe27dUuylg41eButzhlfXymOD1OzO4QCeEHumLISnx+Ib1VttuX8aZxM NGsyxNjnB+3s46FXW5XujjSiyGjtxNjkneTzL+/nTkPqMgbOvywoSuQAexmoVYMopJGA== X-Received: from wrbfm1.prod.google.com ([2002:a05:6000:2801:b0:43f:df99:cb43]) (user=smostafa job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6000:2906:b0:43d:613:4036 with SMTP id ffacd0b85a97d-4493eb6d792mr3587302f8f.37.1777545452617; Thu, 30 Apr 2026 03:37:32 -0700 (PDT) Date: Thu, 30 Apr 2026 10:37:24 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.54.0.545.g6539524ca2-goog Message-ID: <20260430103724.2151625-1-smostafa@google.com> Subject: [PATCH] KVM: arm64: Harden clock for nvhe/pKVM From: Mostafa Saleh To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev Cc: catalin.marinas@arm.com, will@kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, vdonnefort@google.com, tabba@google.com, Mostafa Saleh Content-Type: text/plain; charset="UTF-8" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260430_033735_951528_574E83A0 X-CRM114-Status: GOOD ( 10.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Sashiko(locally) reports possiblity of division by zero and out-of-bounds bitwise shift in trace_clock_update(). Although the clock update is untrusted, we should at least have some basic checks to avoid the clock value getting out of sync if the host is buggy. Signed-off-by: Mostafa Saleh --- arch/arm64/kvm/hyp/nvhe/clock.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/arm64/kvm/hyp/nvhe/clock.c b/arch/arm64/kvm/hyp/nvhe/clock.c index 32fc4313fe43..a7fc61976fd0 100644 --- a/arch/arm64/kvm/hyp/nvhe/clock.c +++ b/arch/arm64/kvm/hyp/nvhe/clock.c @@ -35,6 +35,9 @@ void trace_clock_update(u32 mult, u32 shift, u64 epoch_ns, u64 epoch_cyc) struct clock_data *clock = &trace_clock_data; u64 bank = clock->cur ^ 1; + if (!mult || shift >= 64) + return; + clock->data[bank].mult = mult; clock->data[bank].shift = shift; clock->data[bank].epoch_ns = epoch_ns; -- 2.54.0.545.g6539524ca2-goog