From nobody Mon Sep 29 21:08:02 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5A92C00140 for ; Tue, 16 Aug 2022 00:59:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244043AbiHPA6v (ORCPT ); Mon, 15 Aug 2022 20:58:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347923AbiHPAv4 (ORCPT ); Mon, 15 Aug 2022 20:51:56 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E764DA3C1; Mon, 15 Aug 2022 13:47:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 29BF8B8114A; Mon, 15 Aug 2022 20:47:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BFE6C433D6; Mon, 15 Aug 2022 20:47:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660596430; bh=b36WB6IAy6WVS7Me8ov6v93+IVXEGpv3YEPhTmt49s0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RCyoz3fkCNrky7aByoQ+LF6NT2WJu7Hl9kkkG+DrsaF2OL6yVa6EG0dorhcKmXera UPhqOcCAZTZUIL71BHVnWiUBMAwUbZBHX1ReGNlZyGNmq1tUl/KpVevMo3jcIGa6HY V9qUA1PATiyj9dmCpSXpQBtzKI/8UjbqttXyiYuA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Thomas Gleixner , Eric Biggers , "Jason A. Donenfeld" , Sasha Levin Subject: [PATCH 5.19 1076/1157] timekeeping: contribute wall clock to rng on time change Date: Mon, 15 Aug 2022 20:07:12 +0200 Message-Id: <20220815180523.167658976@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Jason A. Donenfeld [ Upstream commit b8ac29b40183a6038919768b5d189c9bd91ce9b4 ] The rng's random_init() function contributes the real time to the rng at boot time, so that events can at least start in relation to something particular in the real world. But this clock might not yet be set that point in boot, so nothing is contributed. In addition, the relation between minor clock changes from, say, NTP, and the cycle counter is potentially useful entropic data. This commit addresses this by mixing in a time stamp on calls to settimeofday and adjtimex. No entropy is credited in doing so, so it doesn't make initialization faster, but it is still useful input to have. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reviewed-by: Thomas Gleixner Reviewed-by: Eric Biggers Signed-off-by: Jason A. Donenfeld Signed-off-by: Sasha Levin --- kernel/time/timekeeping.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 8e4b3c32fcf9..f72b9f1de178 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -23,6 +23,7 @@ #include #include #include +#include =20 #include "tick-internal.h" #include "ntp_internal.h" @@ -1343,8 +1344,10 @@ int do_settimeofday64(const struct timespec64 *ts) /* Signal hrtimers about time change */ clock_was_set(CLOCK_SET_WALL); =20 - if (!ret) + if (!ret) { audit_tk_injoffset(ts_delta); + add_device_randomness(ts, sizeof(*ts)); + } =20 return ret; } @@ -2430,6 +2433,7 @@ int do_adjtimex(struct __kernel_timex *txc) ret =3D timekeeping_validate_timex(txc); if (ret) return ret; + add_device_randomness(txc, sizeof(*txc)); =20 if (txc->modes & ADJ_SETOFFSET) { struct timespec64 delta; @@ -2447,6 +2451,7 @@ int do_adjtimex(struct __kernel_timex *txc) audit_ntp_init(&ad); =20 ktime_get_real_ts64(&ts); + add_device_randomness(&ts, sizeof(ts)); =20 raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); --=20 2.35.1