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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 568C5C3A59F for ; Fri, 30 Aug 2019 01:11:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2573821726 for ; Fri, 30 Aug 2019 01:11:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567127512; bh=mXSu3yZoOBiiXKChRyUnZ8uuktrSKvYCEZu71UFxXJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=B5ebKeoabaWs1K8B1nqJrlsmaWdqtKA3kY/k2A3xndMpXRGlktcsR73qeRwJpP7yA laggYepawO9S7esRpYO6dMpzuWrd+ekwqKhSmFaJ5LdDrzvQhHi7XIVS27Rzx8GtWk IGqTZ6mass/xPD4L92Kpv4Qx3cWewozBcJbRN9m8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727770AbfH3BLu (ORCPT ); Thu, 29 Aug 2019 21:11:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:58294 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726825AbfH3BLq (ORCPT ); Thu, 29 Aug 2019 21:11:46 -0400 Received: from localhost (c-67-180-165-146.hsd1.ca.comcast.net [67.180.165.146]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 90E6B21897; Fri, 30 Aug 2019 01:11:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567127505; bh=mXSu3yZoOBiiXKChRyUnZ8uuktrSKvYCEZu71UFxXJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YltCN12jd046f5sNbp6uI9OC6JGi1/KU0s1w5+EGSNFun5EsgUSLKB9/cLSrV0c+i ckdQwy9HT/EFN6ANJn1GVqTA4r1PrsdlZmjULXiQAUSiH0i6NrCxj3c9wFiO2nowU/ XXuNApohlIpeLe7ubokYtkAH+v5eIUSTYAYm6+e0= From: Andy Lutomirski To: Theodore Tso Cc: LKML , Linux API , Kees Cook , "Jason A. Donenfeld" , Andy Lutomirski Subject: [PATCH 2/7] random: Add GRND_INSECURE to return best-effort non-cryptographic bytes Date: Thu, 29 Aug 2019 18:11:37 -0700 Message-Id: X-Mailer: git-send-email 2.21.0 In-Reply-To: References: 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 Signed-off-by: Andy Lutomirski --- drivers/char/random.c | 11 +++++++++-- include/uapi/linux/random.h | 2 ++ 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index d152612e08fc..acabb870f222 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2122,7 +2122,14 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, { int ret; - if (flags & ~(GRND_NONBLOCK|GRND_RANDOM)) + if (flags & ~(GRND_NONBLOCK|GRND_RANDOM|GRND_INSECURE)) + return -EINVAL; + + /* + * Requesting insecure and blocking randomness at the same time makes + * no sense. + */ + if ((flags & (GRND_INSECURE|GRND_RANDOM)) == (GRND_INSECURE|GRND_RANDOM)) return -EINVAL; if (count > INT_MAX) @@ -2131,7 +2138,7 @@ SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, if (flags & GRND_RANDOM) return _random_read(flags & GRND_NONBLOCK, buf, count); - if (!crng_ready()) { + if (!(flags & GRND_INSECURE) && !crng_ready()) { if (flags & GRND_NONBLOCK) return -EAGAIN; ret = wait_for_random_bytes(); diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h index 26ee91300e3e..c092d20088d3 100644 --- a/include/uapi/linux/random.h +++ b/include/uapi/linux/random.h @@ -49,8 +49,10 @@ struct rand_pool_info { * * GRND_NONBLOCK Don't block and return EAGAIN instead * GRND_RANDOM Use the /dev/random pool instead of /dev/urandom + * GRND_INSECURE Return non-cryptographic random bytes */ #define GRND_NONBLOCK 0x0001 #define GRND_RANDOM 0x0002 +#define GRND_INSECURE 0x0004 #endif /* _UAPI_LINUX_RANDOM_H */ -- 2.21.0