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[209.132.180.67]) by mx.google.com with ESMTP id t2si4877786otq.196.2019.12.23.00.21.26; Mon, 23 Dec 2019 00:21:35 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b="LP5/95pz"; spf=pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-ext4-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726717AbfLWIVK (ORCPT + 99 others); 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