From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f73.google.com (mail-wr1-f73.google.com [209.85.221.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5F8E7373BE4 for ; Thu, 30 Apr 2026 10:37:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777545455; cv=none; b=GEKEohy+WR8GSBpC+ameRQYvPgzjXbIxnrwgSdgI2RVTZDwjNiGpOhlnkC/hLB39gB08vP4nq2qa88NPXS7z7j+Ea+7mTxqbyynQXgpHGT6wmILraYuJ/SODtDjGVjVFOZvyz085HiEqNb9dqTbN+f6x0b6Z5tZU9dSh4P+kNtg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777545455; c=relaxed/simple; bh=aBUqyz+8tZ7QS3WaHaFr3XJxACwh+4bujNo3pg9HJpg=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=Nlrwv1bzvGShKBD/oDu3/Ddptj+JSjHgx+5qE+AEnUsk07azDMxYaZoxOfVx6bHm4hsqg2t/cEeeIQoPQWEqirJ3t4jDtN106kUPbQf2bJTu3FJv9cf3JAJ6hLa2d8Le9L9DDjp+bTlMfcT2+D1Z+Mkg+j9vkh+lb7wnepZFRxc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=QNmkRWNl; arc=none smtp.client-ip=209.85.221.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--smostafa.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="QNmkRWNl" Received: by mail-wr1-f73.google.com with SMTP id ffacd0b85a97d-43d03065782so450301f8f.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=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=CE7ryhQPSrXB5CO15AITdkHOu/b63A3t1puDBO48YFY=; b=QNmkRWNllXaDwFHf4L7WPAGg0ut4o/xYNR+IxuEIeb/YIb163mwTfoKDwDGLKIDKje 0HInMlSYNbLmnqmuTv5XS/M3uL3sZGvdwTtAi447xfUv4w9qNgAJ2LRiJ52ZV5IAHQsH FMeYTfOBhhPf8nf3MLEiMRKFuAckJfOYGGTbylHek4lAE1pj2DFkqZemvXHLM2sA2jHE +gJCcsa3Z8tiNOO9YN3pgTPQwwjmkTSIZbaYtT1srPDkS9WXxR0obVuW/UjIH7XfzM8e M7rkDIMIc5GizBavAtz4vyUMLfYxJTcj62TWnWNPpR+Zk0EyAMwpz62SPzJ47jJqkyhW 5Oig== 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=tKpnIIKbLNJ3adH8BS15qq4cRQdYoCCjgBN2J39UNjEchalHBNfHFsGKTyMzyc7Dtx eKtuOo/7P/KFZ0wd4ILYYT/TlWo6jHkom/I1OEfLs/IOyMd/232NNGDdfsfzw4eWVDuJ 2MdLfsSpXnFkW3w+ZAoRugtbDigFo/VAarJZxrCN8zcG5vyX/sHP4eVnlAlX+UQbqF9b qCYfEkVaDBiwTKnrm0FBIXHd06mn1aL15q2R/PJ2rf2xrDj2/U45msSwSUf0fY9BUVgc IegUq4DGwms4eCkm9t3bZsZGS/cCGrg3clqPZoG4dhPYpwUO9v5HecD5fFdHHj1Rglfc cGtg== X-Forwarded-Encrypted: i=1; AFNElJ/vEHBycJ9j1vdcuhmc+QvUcW7WzzTzGuVdc2FQjYyB4BqcLCZgYrzQhY0OE6hG+l7Ky4CFEbnJUZJtrvo=@vger.kernel.org X-Gm-Message-State: AOJu0YyTRhdGKZC531bh/J+0iUYvKR8plutt66RDM0ej4qhDIeN/DJBB aMB2300Q64oZHUTrY9xXn6mPLEjS50n9KxwlOHiOyfMkQwb0aZbh0Z69KPONYDbRE+DBuXHKtKH 2/9BtN07096KRjQ== 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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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" 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