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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19E6AC00140 for ; Mon, 15 Aug 2022 19:54:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241961AbiHOTyH (ORCPT ); Mon, 15 Aug 2022 15:54:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42840 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241858AbiHOTxD (ORCPT ); Mon, 15 Aug 2022 15:53:03 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7023AE3A; Mon, 15 Aug 2022 11:50:58 -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 84D16B810A0; Mon, 15 Aug 2022 18:50:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B49BBC433D6; Mon, 15 Aug 2022 18:50:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660589455; bh=PjvIlGHNLRN6F/T3nDYHHiN9EJ37PSPnqadsUE8gwZo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GmEh6MvrhqmWHwp9dPhNc00L1+oWLTWAiYHrysx1cXWbrEpdtpwGaUyZP1KyvcgVW H+5EIJlbl/16jjLO+2QfCHPWuy5z2W4sBZkc4sIw8YoNVd8XRx5V8/P+tYqNkkQ/QU AVZzbDypRBaiZIoJ7rh4VeuxDx/3bs2hn+DdW1KU= 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 5.15 723/779] timekeeping: contribute wall clock to rng on time change Date: Mon, 15 Aug 2022 20:06:07 +0200 Message-Id: <20220815180408.368575578@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 871c912860ed..d6a0ff68df41 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "tick-internal.h" #include "ntp_internal.h" @@ -1326,8 +1327,10 @@ int do_settimeofday64(const struct timespec64 *ts) /* Signal hrtimers about time change */ clock_was_set(CLOCK_SET_WALL); - if (!ret) + if (!ret) { audit_tk_injoffset(ts_delta); + add_device_randomness(ts, sizeof(*ts)); + } return ret; } @@ -2413,6 +2416,7 @@ int do_adjtimex(struct __kernel_timex *txc) ret = timekeeping_validate_timex(txc); if (ret) return ret; + add_device_randomness(txc, sizeof(*txc)); if (txc->modes & ADJ_SETOFFSET) { struct timespec64 delta; @@ -2430,6 +2434,7 @@ int do_adjtimex(struct __kernel_timex *txc) audit_ntp_init(&ad); ktime_get_real_ts64(&ts); + add_device_randomness(&ts, sizeof(ts)); raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); -- 2.35.1