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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 212EAC43334 for ; Thu, 23 Jun 2022 17:20:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233480AbiFWRUL (ORCPT ); Thu, 23 Jun 2022 13:20:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233889AbiFWRSQ (ORCPT ); Thu, 23 Jun 2022 13:18:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C29B988B23; Thu, 23 Jun 2022 10:00:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 17DEF615E2; Thu, 23 Jun 2022 17:00:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D08BDC385A2; Thu, 23 Jun 2022 17:00:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656003615; bh=KUyaYx+e07AqBn8aUU+8AeMNrUoj9SxwJLatg/eXu74=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WPKb43OaW8jkKoXWzIm9pqkxDAGeWkwggyp440sZXkEBu/Q3iCxKLaWMlQnN/uVVR tTk7mPmKIupMZ+7RNtCPrlzprykKu3DU5iFrE5DlB0YF6PiZWa5bBgEi8uBNqB4idG RUSXSq45cu4/FSzZrLu1J7SRAc/Sb9jXu46WHao8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Theodore Tso , "Jason A. Donenfeld" Subject: [PATCH 4.14 031/237] random: add GRND_INSECURE to return best-effort non-cryptographic bytes Date: Thu, 23 Jun 2022 18:41:05 +0200 Message-Id: <20220623164344.052180658@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164343.132308638@linuxfoundation.org> References: <20220623164343.132308638@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andy Lutomirski commit 75551dbf112c992bc6c99a972990b3f272247e23 upstream. Signed-off-by: Andy Lutomirski Link: https://lore.kernel.org/r/d5473b56cf1fa900ca4bd2b3fc1e5b8874399919.1577088521.git.luto@kernel.org Signed-off-by: Theodore Ts'o Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 11 +++++++++-- include/uapi/linux/random.h | 2 ++ 2 files changed, 11 insertions(+), 2 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2134,7 +2134,14 @@ SYSCALL_DEFINE3(getrandom, char __user * { 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) @@ -2143,7 +2150,7 @@ SYSCALL_DEFINE3(getrandom, char __user * 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(); --- 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 */