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 70006C433EF for ; Mon, 20 Jun 2022 13:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348517AbiFTNpt (ORCPT ); Mon, 20 Jun 2022 09:45:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348903AbiFTNn7 (ORCPT ); Mon, 20 Jun 2022 09:43:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D77532C653; Mon, 20 Jun 2022 06:16:03 -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 ams.source.kernel.org (Postfix) with ESMTPS id 8257CB811E3; Mon, 20 Jun 2022 13:10:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0040C3411B; Mon, 20 Jun 2022 13:10:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655730642; bh=HE8iMqlHztMzX9EeQuj+Az3zcpbQEHqL2jzZjC7T6Eg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TPs1IIkz8uCA1Howki+DKBgltfLI96WthIyEq7aEM0zAlD1hBSMr1hN29RDVhGQwj b3p/wDZtXfQwSr/tziVP8NJ7fw10DTSgJDgV+mhRJyGUWjVPsKV2X/afW8+R76d71a F5To29ITvOoKyqFrt4c0+vdnlsQyOzmY0FwB9QEA= 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 5.4 011/240] random: add GRND_INSECURE to return best-effort non-cryptographic bytes Date: Mon, 20 Jun 2022 14:48:32 +0200 Message-Id: <20220620124738.135287998@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220620124737.799371052@linuxfoundation.org> References: <20220620124737.799371052@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 @@ -2217,7 +2217,14 @@ 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) @@ -2226,7 +2233,7 @@ 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 */