From nobody Tue Dec 16 11:42:49 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 29CA4C28B2B for ; Fri, 19 Aug 2022 16:47:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353967AbiHSQrK (ORCPT ); Fri, 19 Aug 2022 12:47:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1353876AbiHSQpN (ORCPT ); Fri, 19 Aug 2022 12:45:13 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 18364108967; Fri, 19 Aug 2022 09:11:32 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 0C2796181D; Fri, 19 Aug 2022 16:10:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1433EC433D6; Fri, 19 Aug 2022 16:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660925440; bh=hVUJ72nZ/V0jcQbOqOoLv0prB9eEJBlnpXj47lIaUnY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aFMh3TgkLA/KJmSj9ciendWddTY/KR3m48f2aN57aZUtF64xQRWPKxMDCe2nyVX/6 9h7enpOVfT5O/IxWykwhNktBDgVn/9H8qryHGTLTslwOYn4VwFI2POgpAZpVLSRI/H ni5/kwkoKwJv98lZEU24RUYUnu8fShrY3F3TFEls= 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 5.10 491/545] timekeeping: contribute wall clock to rng on time change Date: Fri, 19 Aug 2022 17:44:21 +0200 Message-Id: <20220819153851.426949216@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220819153829.135562864@linuxfoundation.org> References: <20220819153829.135562864@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 e12ce2821dba..d9b48f7a35e0 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" @@ -1330,8 +1331,10 @@ int do_settimeofday64(const struct timespec64 *ts) /* signal hrtimers about time change */ clock_was_set(); =20 - if (!ret) + if (!ret) { audit_tk_injoffset(ts_delta); + add_device_randomness(ts, sizeof(*ts)); + } =20 return ret; } @@ -2410,6 +2413,7 @@ 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; @@ -2427,6 +2431,7 @@ 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