From mboxrd@z Thu Jan 1 00:00:00 1970 Delivery-date: Wed, 28 May 2025 18:28:58 +0200 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by lore.white.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uKJeE-001FPy-2A for lore@lore.pengutronix.de; Wed, 28 May 2025 18:28:58 +0200 Received: from bombadil.infradead.org ([2607:7c80:54:3::133]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uKJe9-0001r5-9W for lore@pengutronix.de; Wed, 28 May 2025 18:28:58 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=O+yPci6s8Wv08ZUISc+/NSbB/VfpPotTjCVEuk8TVjM=; b=SP/gE3rev/Av04e9GoWaGIJlyR baQaZhdPWhY5m3+6gWg3lHz4UKINXWh6McAjp3jmkJw5kd+ra6WJSabLnY/zWu1K6kGo1A0Geqqx6 ndoi0a3ihdIYTadaNXLDPoXiHWZKxLCC0+bgWMyB61dJ4zoKXcPRdusajILRfTaFJ4QCtXE8+b43E /gll7vzxhTeCzuzZrGoXix7W3tt3ZDSm5bQeXIPBAc/fuTeQEPbMZylXiLpspX+LcnhSTiiusBFec d7e2SR+/UxQwAvTgy5tCHALSTf2QmKAhqCWfui17ZLpwye9SM+3xJt9+3eMmdqxbbLtNpipJUDbRc lWLrPrug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uKJdU-0000000Df1I-1apB; Wed, 28 May 2025 16:28:12 +0000 Received: from metis.whiteo.stw.pengutronix.de ([2a0a:edc0:2:b01:1d::104]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uKIqC-0000000DZNc-33if for barebox@lists.infradead.org; Wed, 28 May 2025 15:37:17 +0000 Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1uKIqB-0005Ol-Bm; Wed, 28 May 2025 17:37:15 +0200 Received: from dude05.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::54]) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1uKIqB-000c2y-0a; Wed, 28 May 2025 17:37:15 +0200 Received: from localhost ([::1] helo=dude05.red.stw.pengutronix.de) by dude05.red.stw.pengutronix.de with esmtp (Exim 4.96) (envelope-from ) id 1uKIqB-002fZp-0I; Wed, 28 May 2025 17:37:15 +0200 From: Ahmad Fatoum To: barebox@lists.infradead.org Cc: Ahmad Fatoum Date: Wed, 28 May 2025 17:37:09 +0200 Message-Id: <20250528153709.636444-1-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.39.5 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250528_083716_767381_39BD1FC2 X-CRM114-Status: GOOD ( 10.50 ) X-BeenThere: barebox@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "barebox" X-SA-Exim-Connect-IP: 2607:7c80:54:3::133 X-SA-Exim-Mail-From: barebox-bounces+lore=pengutronix.de@lists.infradead.org X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on metis.whiteo.stw.pengutronix.de X-Spam-Level: X-Spam-Status: No, score=-6.7 required=4.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Subject: [PATCH] lib: random: add CONFIG_INSECURE logging of seeds X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on metis.whiteo.stw.pengutronix.de) clocksource_srand() can be called after events that take a varying amount of time to extract some entropy. To get an idea about how much entropy we are getting out, add a CONFIG_INSECURE-guarded debug print that prints the seeds out as-is. Signed-off-by: Ahmad Fatoum --- lib/random.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lib/random.c b/lib/random.c index 889d314e0fad..632f361c4627 100644 --- a/lib/random.c +++ b/lib/random.c @@ -11,6 +11,8 @@ * CONFIG_ALLOW_PRNG_FALLBACK set, which will emit a warning at runtime. */ +#define pr_fmt(fmt) "random: " fmt + #include #include #include @@ -75,6 +77,12 @@ void randbuf_r(u64 *x, void *buf, size_t len) */ void srand_xor(u64 entropy) { + /* The PRNG shouldn't be used for crypto anyway, but still let's not + * divulge the whole state in secure configurations. + */ + if (IS_ENABLED(CONFIG_INSECURE)) + pr_debug("PRNG seeded with %llu\n", entropy); + prng_state ^= entropy; /* Ensure prng_state is never zero */ prng_state += !prng_state; -- 2.39.5