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[23.128.96.18]) by mx.google.com with ESMTP id d11si7385140edv.203.2020.04.15.18.07.45; Wed, 15 Apr 2020 18:08:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2636968AbgDOVG0 (ORCPT + 99 others); Wed, 15 Apr 2020 17:06:26 -0400 Received: from mga03.intel.com ([134.134.136.65]:64170 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2442224AbgDOVFb (ORCPT ); Wed, 15 Apr 2020 17:05:31 -0400 IronPort-SDR: jiIgtiYM3WeGGNc0wk1n7TUWtkENP409LXoGjU3HQI5NIFp8az/dalw3bsMiQnQingqIWVBmVy Ej7Ye2V+5pYg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 14:05:18 -0700 IronPort-SDR: 7n8pRWt0V1GeJc9ECBQITu9uGiTez3QAZq7Wl8D0+wef+n1oKTjTuiwn6XciFIP7visxU7Khkz sHR9mObX3jFA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,388,1580803200"; d="scan'208";a="455035542" Received: from kcaccard-mobl.amr.corp.intel.com (HELO kcaccard-mobl1.jf.intel.com) ([10.209.116.191]) by fmsmga006.fm.intel.com with ESMTP; 15 Apr 2020 14:05:12 -0700 From: Kristen Carlson Accardi To: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org Cc: arjan@linux.intel.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecomb@intel.com Subject: [PATCH 3/9] x86/boot: Allow a "silent" kaslr random byte fetch Date: Wed, 15 Apr 2020 14:04:45 -0700 Message-Id: <20200415210452.27436-4-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200415210452.27436-1-kristen@linux.intel.com> References: <20200415210452.27436-1-kristen@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook Under earlyprintk, each RNG call produces a debug report line. When shuffling hundreds of functions, this is not useful information (each line is identical and tells us nothing new). Instead, allow for a NULL "purpose" to suppress the debug reporting. Signed-off-by: Kees Cook Signed-off-by: Kristen Carlson Accardi --- arch/x86/lib/kaslr.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/arch/x86/lib/kaslr.c b/arch/x86/lib/kaslr.c index a53665116458..2b3eb8c948a3 100644 --- a/arch/x86/lib/kaslr.c +++ b/arch/x86/lib/kaslr.c @@ -56,11 +56,14 @@ unsigned long kaslr_get_random_long(const char *purpose) unsigned long raw, random = get_boot_seed(); bool use_i8254 = true; - debug_putstr(purpose); - debug_putstr(" KASLR using"); + if (purpose) { + debug_putstr(purpose); + debug_putstr(" KASLR using"); + } if (has_cpuflag(X86_FEATURE_RDRAND)) { - debug_putstr(" RDRAND"); + if (purpose) + debug_putstr(" RDRAND"); if (rdrand_long(&raw)) { random ^= raw; use_i8254 = false; @@ -68,7 +71,8 @@ unsigned long kaslr_get_random_long(const char *purpose) } if (has_cpuflag(X86_FEATURE_TSC)) { - debug_putstr(" RDTSC"); + if (purpose) + debug_putstr(" RDTSC"); raw = rdtsc(); random ^= raw; @@ -76,7 +80,8 @@ unsigned long kaslr_get_random_long(const char *purpose) } if (use_i8254) { - debug_putstr(" i8254"); + if (purpose) + debug_putstr(" i8254"); random ^= i8254(); } @@ -86,7 +91,8 @@ unsigned long kaslr_get_random_long(const char *purpose) : "a" (random), "rm" (mix_const)); random += raw; - debug_putstr("...\n"); + if (purpose) + debug_putstr("...\n"); return random; } -- 2.20.1