From nobody Fri Sep 5 20:11:09 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 4F20DC32792 for ; Tue, 23 Aug 2022 11:45:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1358305AbiHWLpQ (ORCPT ); Tue, 23 Aug 2022 07:45:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358401AbiHWLlq (ORCPT ); Tue, 23 Aug 2022 07:41:46 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10A98CCE06; Tue, 23 Aug 2022 02:29:16 -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 F27ABB81C89; Tue, 23 Aug 2022 09:29:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49C52C433C1; Tue, 23 Aug 2022 09:29:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1661246953; bh=63vkLkyEoeEDrcdO9ortIL1p5PxwtfRUw7TLH+InspY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Qp5Bsez6hhF/ctgZTbQ4/TAFD5/XwBHFc0exxSG4V5TAF+5ehnTgC8A9NQ0+APo6i 1BFNpv3OxNnnHj6m0T2ueWt2cJfFuhUAQQSNNYyPloEI7r2Rv3QlS1AdbZlwSMzxqQ sc26C6hA2c5thAJq0I/4D7/r9YuM99Xoi0ntv5sg= 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" Subject: [PATCH 5.4 272/389] timekeeping: contribute wall clock to rng on time change Date: Tue, 23 Aug 2022 10:25:50 +0200 Message-Id: <20220823080126.919788970@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220823080115.331990024@linuxfoundation.org> References: <20220823080115.331990024@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 commit b8ac29b40183a6038919768b5d189c9bd91ce9b4 upstream. 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: Greg Kroah-Hartman --- kernel/time/timekeeping.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- 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" @@ -1256,8 +1257,10 @@ out: /* 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; } @@ -2336,6 +2339,7 @@ int do_adjtimex(struct __kernel_timex *t 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; @@ -2353,6 +2357,7 @@ int do_adjtimex(struct __kernel_timex *t 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);