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=-8.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 66F9EC04AAF for ; Fri, 17 May 2019 02:53:18 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 20C172082E for ; Fri, 17 May 2019 02:53:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="cGU7oRev" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20C172082E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:40285 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hRSzl-00081p-DB for qemu-devel@archiver.kernel.org; Thu, 16 May 2019 22:53:17 -0400 Received: from eggs.gnu.org ([209.51.188.92]:39058) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hRSmc-0005WJ-Mp for qemu-devel@nongnu.org; Thu, 16 May 2019 22:39:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hRSmb-00027B-0B for qemu-devel@nongnu.org; Thu, 16 May 2019 22:39:42 -0400 Received: from mail-pf1-x444.google.com ([2607:f8b0:4864:20::444]:44263) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hRSma-00026S-Lr for qemu-devel@nongnu.org; Thu, 16 May 2019 22:39:40 -0400 Received: by mail-pf1-x444.google.com with SMTP id g9so2857696pfo.11 for ; Thu, 16 May 2019 19:39:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=4MrsM8HWkl5HnptGJNmid/oZc3Q7MB8Exr59LxaGIMY=; b=cGU7oRev0s/zz1mO46oi6pyQu7KKEY0tYpiTGOo1MaO24Y1uEAnV+rfgDeyi1GPAsL dJQNNn8i+jmPuwdvgggGg/cQdqjb1p5NNtjj4n6dqN7skGXPLJhNGBCDDAeHhrJSyc98 +pITmixniajrzdOw83mfFNtdXkGsF/E8iYWwK4BVIq+/2ZoBu1yjzStP0NHnzaZ7JPdI rvpz6Zm4EaQJ0JCK1r3guMjJPPDKeuvdx9YR2IrG1vGQkU3djQ5p53pq2scFruXNiicB pKtoEFDEiqQbDjAI3wIszA2eZMqfb+N1LXlaWuSTRGpTgBnvlQTHwyyxIzyBqD4FfzRo SH4A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=4MrsM8HWkl5HnptGJNmid/oZc3Q7MB8Exr59LxaGIMY=; b=qgZGCs1+v0FancpZdewNJwbHxsa+sdwAPeZ/eZbQ4q+hNzCdflPGiLHmxe9AqvNuH5 tqqA1UPF3qFz3XJeavMkPHc5cG6huFHUl+95XO0H6ZjPnGbLyZFb92hUZxpz5bYgfIIY Y7YiTWhX3rmVpDLZXbk1yiku182Uzbz1rJv8VLSW7utMEd02gAIbTMtRrxSLn/fj3tuW rDYRcUNp+8CRz3Y6Qi8vhruaUqwBbEPMNQRRnYhLku5AFOp2PDgUK1iyr0C+iFv4roau RM2Ib5Ognn0cY5RUYZz029nJw/l61xxuML1ts3LlkeMPaJ685k6fXz9REuh59SXrOQXe MOkQ== X-Gm-Message-State: APjAAAUhBiQFNY2VR8yG8JTN+8srvYkgf+svqc9E6IPYTy6RtQVlalVS Wt/nde+dfeIkWo3IpvcimeJsrlDXT7E= X-Google-Smtp-Source: APXvYqwYzmb/JnS/apu9OPzq1FItV1NWFiXz53Cpqy8V/hoAgE+pwKfihEvvmLbyMDRG7/tURTVWYg== X-Received: by 2002:a63:550c:: with SMTP id j12mr53738475pgb.450.1558060779255; Thu, 16 May 2019 19:39:39 -0700 (PDT) Received: from localhost.localdomain (97-113-13-231.tukw.qwest.net. [97.113.13.231]) by smtp.gmail.com with ESMTPSA id w6sm6984152pge.30.2019.05.16.19.39.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 May 2019 19:39:38 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Thu, 16 May 2019 19:39:09 -0700 Message-Id: <20190517023924.1686-11-richard.henderson@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190517023924.1686-1-richard.henderson@linaro.org> References: <20190517023924.1686-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::444 Subject: [Qemu-devel] [PATCH v8 10/25] util: Add qemu_guest_getrandom and associated routines X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lvivier@redhat.com, berrange@redhat.com, armbru@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This routine is intended to produce high-quality random numbers to the guest. Normally, such numbers are crypto quality from the host, but a command-line option can force the use of a fully deterministic sequence for use while debugging. Reviewed-by: Laurent Vivier Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Daniel P. Berrangé Signed-off-by: Richard Henderson --- include/qemu/guest-random.h | 68 +++++++++++++++++++++++++++ util/guest-random.c | 93 +++++++++++++++++++++++++++++++++++++ util/Makefile.objs | 1 + 3 files changed, 162 insertions(+) create mode 100644 include/qemu/guest-random.h create mode 100644 util/guest-random.c diff --git a/include/qemu/guest-random.h b/include/qemu/guest-random.h new file mode 100644 index 0000000000..09ff9c2236 --- /dev/null +++ b/include/qemu/guest-random.h @@ -0,0 +1,68 @@ +/* + * QEMU guest-visible random functions + * + * Copyright 2019 Linaro, Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#ifndef QEMU_GUEST_RANDOM_H +#define QEMU_GUEST_RANDOM_H + +/** + * qemu_guest_random_seed_main(const char *optarg, Error **errp) + * @optarg: a non-NULL pointer to a C string + * @errp: an error indicator + * + * The @optarg value is that which accompanies the -seed argument. + * This forces qemu_guest_getrandom into deterministic mode. + * + * Returns 0 on success, < 0 on failure while setting *errp. + */ +int qemu_guest_random_seed_main(const char *optarg, Error **errp); + +/** + * qemu_guest_random_seed_thread_part1(void) + * + * If qemu_getrandom is in deterministic mode, returns an + * independent seed for the new thread. Otherwise returns 0. + */ +uint64_t qemu_guest_random_seed_thread_part1(void); + +/** + * qemu_guest_random_seed_thread_part2(uint64_t seed) + * @seed: a value for the new thread. + * + * If qemu_guest_getrandom is in deterministic mode, this stores an + * independent seed for the new thread. Otherwise a no-op. + */ +void qemu_guest_random_seed_thread_part2(uint64_t seed); + +/** + * qemu_guest_getrandom(void *buf, size_t len, Error **errp) + * @buf: a buffer of bytes to be written + * @len: the number of bytes in @buf + * @errp: an error indicator + * + * Fills len bytes in buf with random data. This should only be used + * for data presented to the guest. Host-side crypto services should + * use qcrypto_random_bytes. + * + * Returns 0 on success, < 0 on failure while setting *errp. + */ +int qemu_guest_getrandom(void *buf, size_t len, Error **errp); + +/** + * qemu_guest_getrandom_nofail(void *buf, size_t len) + * @buf: a buffer of bytes to be written + * @len: the number of bytes in @buf + * + * Like qemu_guest_getrandom, but will assert for failure. + * Use this when there is no reasonable recovery. + */ +void qemu_guest_getrandom_nofail(void *buf, size_t len); + +#endif /* QEMU_GUEST_RANDOM_H */ diff --git a/util/guest-random.c b/util/guest-random.c new file mode 100644 index 0000000000..e8124a3cad --- /dev/null +++ b/util/guest-random.c @@ -0,0 +1,93 @@ +/* + * QEMU guest-visible random functions + * + * Copyright 2019 Linaro, Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include "qemu/osdep.h" +#include "qemu-common.h" +#include "qemu/cutils.h" +#include "qapi/error.h" +#include "qemu/guest-random.h" +#include "crypto/random.h" + + +static __thread GRand *thread_rand; +static bool deterministic; + + +static int glib_random_bytes(void *buf, size_t len) +{ + GRand *rand = thread_rand; + size_t i; + uint32_t x; + + if (unlikely(rand == NULL)) { + /* Thread not initialized for a cpu, or main w/o -seed. */ + thread_rand = rand = g_rand_new(); + } + + for (i = 0; i + 4 <= len; i += 4) { + x = g_rand_int(rand); + __builtin_memcpy(buf + i, &x, 4); + } + if (i < len) { + x = g_rand_int(rand); + __builtin_memcpy(buf + i, &x, i - len); + } + return 0; +} + +int qemu_guest_getrandom(void *buf, size_t len, Error **errp) +{ + if (unlikely(deterministic)) { + /* Deterministic implementation using Glib's Mersenne Twister. */ + return glib_random_bytes(buf, len); + } else { + /* Non-deterministic implementation using crypto routines. */ + return qcrypto_random_bytes(buf, len, errp); + } +} + +void qemu_guest_getrandom_nofail(void *buf, size_t len) +{ + qemu_guest_getrandom(buf, len, &error_fatal); +} + +uint64_t qemu_guest_random_seed_thread_part1(void) +{ + if (deterministic) { + uint64_t ret; + glib_random_bytes(&ret, sizeof(ret)); + return ret; + } + return 0; +} + +void qemu_guest_random_seed_thread_part2(uint64_t seed) +{ + g_assert(thread_rand == NULL); + if (deterministic) { + thread_rand = + g_rand_new_with_seed_array((const guint32 *)&seed, + sizeof(seed) / sizeof(guint32)); + } +} + +int qemu_guest_random_seed_main(const char *optarg, Error **errp) +{ + unsigned long long seed; + if (parse_uint_full(optarg, &seed, 0)) { + error_setg(errp, "Invalid seed number: %s", optarg); + return -1; + } else { + deterministic = true; + qemu_guest_random_seed_thread_part2(seed); + return 0; + } +} diff --git a/util/Makefile.objs b/util/Makefile.objs index 9206878dec..c27a923dbe 100644 --- a/util/Makefile.objs +++ b/util/Makefile.objs @@ -54,5 +54,6 @@ util-obj-y += iova-tree.o util-obj-$(CONFIG_INOTIFY1) += filemonitor-inotify.o util-obj-$(CONFIG_LINUX) += vfio-helpers.o util-obj-$(CONFIG_OPENGL) += drm.o +util-obj-y += guest-random.o stub-obj-y += filemonitor-stub.o -- 2.17.1