From patchwork Wed Oct 31 22:00:30 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anthony Liguori X-Patchwork-Id: 196020 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 0B74B2C01C6 for ; Thu, 1 Nov 2012 09:21:40 +1100 (EST) Received: from localhost ([::1]:35650 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTgMW-0001rA-89 for incoming@patchwork.ozlabs.org; Wed, 31 Oct 2012 18:02:12 -0400 Received: from eggs.gnu.org ([208.118.235.92]:36410) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTgLr-0000Xa-Pl for qemu-devel@nongnu.org; Wed, 31 Oct 2012 18:01:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TTgLq-0005Gg-DI for qemu-devel@nongnu.org; Wed, 31 Oct 2012 18:01:31 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:52147) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTgLp-0005GG-Ev for qemu-devel@nongnu.org; Wed, 31 Oct 2012 18:01:30 -0400 Received: from /spool/local by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Thu, 1 Nov 2012 03:31:00 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q9VM10Sc40108176 for ; Thu, 1 Nov 2012 03:31:00 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id qA13Up45020846 for ; Thu, 1 Nov 2012 14:30:51 +1100 Received: from titi.austin.rr.com (sig-9-48-82-197.mts.ibm.com [9.48.82.197]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id qA13UWFT019674; Thu, 1 Nov 2012 14:30:48 +1100 From: Anthony Liguori To: qemu-devel@nongnu.org Date: Wed, 31 Oct 2012 17:00:30 -0500 Message-Id: <1351720834-22805-5-git-send-email-aliguori@us.ibm.com> X-Mailer: git-send-email 1.8.0 In-Reply-To: <1351720834-22805-1-git-send-email-aliguori@us.ibm.com> References: <1351720834-22805-1-git-send-email-aliguori@us.ibm.com> x-cbid: 12103122-8878-0000-0000-000004974686 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.4.x-2.6.x [generic] X-Received-From: 122.248.162.7 Cc: Amit Shah , Paolo Bonzini , Anthony Liguori , Andreas Faerber , "H. Peter Anvin" Subject: [Qemu-devel] [PATCH 4/8] rng-random: add an RNG backend that uses /dev/random (v3) X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The filename can be overridden but it expects a non-blocking source of entropy. A typical invocation would be: qemu -object rng-random,id=rng0 -device virtio-rng-pci,rng=rng0 This can also be used with /dev/urandom by using the command line: qemu -object rng-random,filename=/dev/urandom,id=rng0 \ -device virtio-rng-pci,rng=rng0 Signed-off-by: Anthony Liguori --- v1 -> v2 - merged header split patch into this one v2 -> v3 - bug fix in rng-random (Paolo) --- backends/Makefile.objs | 2 +- backends/rng-random.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++ include/qemu/rng-random.h | 22 +++++++ 3 files changed, 184 insertions(+), 1 deletion(-) create mode 100644 backends/rng-random.c create mode 100644 include/qemu/rng-random.h diff --git a/backends/Makefile.objs b/backends/Makefile.objs index 06e08c7..23ca19b 100644 --- a/backends/Makefile.objs +++ b/backends/Makefile.objs @@ -1 +1 @@ -common-obj-y += rng.o +common-obj-y += rng.o rng-random.o diff --git a/backends/rng-random.c b/backends/rng-random.c new file mode 100644 index 0000000..9c9923b --- /dev/null +++ b/backends/rng-random.c @@ -0,0 +1,161 @@ +/* + * QEMU Random Number Generator Backend + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/rng-random.h" +#include "qemu/rng.h" +#include "qerror.h" +#include "main-loop.h" + +struct RndRandom +{ + RngBackend parent; + + int fd; + char *filename; + + EntropyReceiveFunc *receive_func; + void *opaque; + size_t size; +}; + +/** + * A simple and incomplete backend to request entropy from /dev/random. + * + * This backend exposes an additional "filename" property that can be used to + * set the filename to use to open the backend. + */ + +static void entropy_available(void *opaque) +{ + RndRandom *s = RNG_RANDOM(opaque); + uint8_t buffer[s->size]; + ssize_t len; + + len = read(s->fd, buffer, s->size); + g_assert(len != -1); + + s->receive_func(s->opaque, buffer, len); + s->receive_func = NULL; + + qemu_set_fd_handler(s->fd, NULL, NULL, NULL); +} + +static void rng_random_request_entropy(RngBackend *b, size_t size, + EntropyReceiveFunc *receive_entropy, + void *opaque) +{ + RndRandom *s = RNG_RANDOM(b); + + if (s->receive_func) { + s->receive_func(s->opaque, NULL, 0); + } + + s->receive_func = receive_entropy; + s->opaque = opaque; + s->size = size; + + qemu_set_fd_handler(s->fd, entropy_available, NULL, s); +} + +static void rng_random_opened(RngBackend *b, Error **errp) +{ + RndRandom *s = RNG_RANDOM(b); + + if (s->filename == NULL) { + error_set(errp, QERR_INVALID_PARAMETER_VALUE, + "filename", "a valid filename"); + } else { + s->fd = open(s->filename, O_RDONLY | O_NONBLOCK); + + if (s->fd == -1) { + error_set(errp, QERR_OPEN_FILE_FAILED, s->filename); + } + } +} + +static char *rng_random_get_filename(Object *obj, Error **errp) +{ + RndRandom *s = RNG_RANDOM(obj); + + if (s->filename) { + return g_strdup(s->filename); + } + + return NULL; +} + +static void rng_random_set_filename(Object *obj, const char *filename, + Error **errp) +{ + RngBackend *b = RNG_BACKEND(obj); + RndRandom *s = RNG_RANDOM(obj); + + if (b->opened) { + error_set(errp, QERR_PERMISSION_DENIED); + return; + } + + if (s->filename) { + g_free(s->filename); + } + + s->filename = g_strdup(filename); +} + +static void rng_random_init(Object *obj) +{ + RndRandom *s = RNG_RANDOM(obj); + + object_property_add_str(obj, "filename", + rng_random_get_filename, + rng_random_set_filename, + NULL); + + s->filename = g_strdup("/dev/random"); +} + +static void rng_random_finalize(Object *obj) +{ + RndRandom *s = RNG_RANDOM(obj); + + qemu_set_fd_handler(s->fd, NULL, NULL, NULL); + + if (s->fd != -1) { + close(s->fd); + } + + g_free(s->filename); +} + +static void rng_random_class_init(ObjectClass *klass, void *data) +{ + RngBackendClass *rbc = RNG_BACKEND_CLASS(klass); + + rbc->request_entropy = rng_random_request_entropy; + rbc->opened = rng_random_opened; +} + +static TypeInfo rng_random_info = { + .name = TYPE_RNG_RANDOM, + .parent = TYPE_RNG_BACKEND, + .instance_size = sizeof(RndRandom), + .class_init = rng_random_class_init, + .instance_init = rng_random_init, + .instance_finalize = rng_random_finalize, +}; + +static void register_types(void) +{ + type_register_static(&rng_random_info); +} + +type_init(register_types); diff --git a/include/qemu/rng-random.h b/include/qemu/rng-random.h new file mode 100644 index 0000000..6249290 --- /dev/null +++ b/include/qemu/rng-random.h @@ -0,0 +1,22 @@ +/* + * QEMU Random Number Generator Backend + * + * Copyright IBM, Corp. 2012 + * + * Authors: + * Anthony Liguori + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ +#ifndef QEMU_RNG_RANDOM_H +#define QEMU_RNG_RANDOM_H + +#include "qemu/object.h" + +#define TYPE_RNG_RANDOM "rng-random" +#define RNG_RANDOM(obj) OBJECT_CHECK(RndRandom, (obj), TYPE_RNG_RANDOM) + +typedef struct RndRandom RndRandom; + +#endif