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 844E8C2D0C0 for ; Mon, 23 Dec 2019 08:21:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56090207FF for ; Mon, 23 Dec 2019 08:21:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577089271; bh=yhFKFV2M8IVRdKt/jk/YAVP+IDJiL/eZhJKGWL/fJmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=hTjhoeNRkhMXHFNqXQjQ9SnF+q4G96+jdhJY2uIpVsoTIsyl6OdxonR+bg/UxheON 1Jf3EwFp89a7AOb7rMztKzXW2wTl/0isNzqiMYXNl9KeNofo/HcPdjNrhPoYEW0YzL e29WllrLZErXg4nFtRXDGC+w0igUIk0I1WSnxnqo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726733AbfLWIVK (ORCPT ); Mon, 23 Dec 2019 03:21:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:38772 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726680AbfLWIVJ (ORCPT ); Mon, 23 Dec 2019 03:21:09 -0500 Received: from localhost (36-236-5-169.dynamic-ip.hinet.net [36.236.5.169]) (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 53A862073A; Mon, 23 Dec 2019 08:21:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577089268; bh=yhFKFV2M8IVRdKt/jk/YAVP+IDJiL/eZhJKGWL/fJmw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LP5/95pzggJ/fF7QjTRyw5EkeWW7uhGq0dh2s7OfKwpm/EeAeFyGB5OMU7pV6R38Y 2gt10UaeFCR7EMKrE8YVRQD3hAH+1sJPwDUtyaj0AXM88mEs2+2Pe9uYh3mqSmn0pZ 5XAchGRv2tYQa+cSRdo/+ChDo9tzZkDGgAWbca0A= From: Andy Lutomirski To: Ted Ts'o Cc: LKML , Linux API , Kees Cook , "Jason A. Donenfeld" , "Ahmed S. Darwish" , Lennart Poettering , "Eric W. Biederman" , "Alexander E. Patrakov" , Michael Kerrisk , Willy Tarreau , Matthew Garrett , Ext4 Developers List , linux-man , Stephan Mueller , Andy Lutomirski Subject: [PATCH v3 3/8] random: Add GRND_INSECURE to return best-effort non-cryptographic bytes Date: Mon, 23 Dec 2019 00:20:46 -0800 Message-Id: X-Mailer: git-send-email 2.23.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@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 7b46751772e5..675b8a48e18a 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2193,7 +2193,14 @@ 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) @@ -2202,7 +2209,7 @@ 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 */ -- 2.23.0