[Xen-devel] Re: [PATCH, v4]: xl: randomly generate UUID''s

Christoph Egger
Mon, 30 Aug 2010 12:51:23 -0000

On Friday 27 August 2010 19:34:00 Gianni Tedesco wrote:
> Changes since v3:
>  - Fix LIBXL_UUID_BYTES on NetBSD. Note that the code assumes
>    uint8_t[16] to always be interchangeable with libxl_uuid_t.
>  - Return error messages when uuid_parse fails, spotted by Owen Smith
>  - Implement "uuid" parameter in xl and exit with an error if
parse
>    fails
> Changes since v2:
>  - Re-based to remove orthogonal concern of UUID string formatting fixed
>    in 22001:0b6f82eaaea9 "xl: make libxl_uuid2string internal to
> libxenlight" - Incorporated Christoph Egger''s suggestions

I will test this.

Christoph


> 8<---------------------------------------------------------------
> This patch converts xl to randomly generate UUID''s rather than
using a
> dodgy time-seeded PRNG. I have ignored various suggestions so far on
> auto-generation of MAC addresses and left it as a topic for a future
> patch to solve. In other words the behaviour stays the same it''s
just
> using a true random source. This patch also implements the "uuid"
config
> file parameter in xl.
>
> Signed-off-by: Gianni Tedesco <gianni.tedesco@citrix.com>
>
> diff -r 3c4c3d48a835 tools/libxl/Makefile
> --- a/tools/libxl/Makefile      Thu Aug 26 11:16:56 2010 +0100
> +++ b/tools/libxl/Makefile      Fri Aug 27 18:27:27 2010 +0100
> @@ -16,6 +16,9 @@ CFLAGS += -I. -fPIC
>  CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest) $(CFLAGS_libxenstore)
> $(CFLAGS_libblktapctl)
>
>  LIBS = $(LDLIBS_libxenctrl) $(LDLIBS_libxenguest) $(LDLIBS_libxenstore)
> $(LDLIBS_libblktapctl) $(UTIL_LIBS) +ifeq ($(CONFIG_Linux),y)
> +LIBS += -luuid
> +endif
>
>  LIBXL_OBJS-y = osdeps.o libxl_paths.o libxl_bootloader.o
>  ifeq ($(LIBXL_BLKTAP),y)
> diff -r 3c4c3d48a835 tools/libxl/libxl.c
> --- a/tools/libxl/libxl.c       Thu Aug 26 11:16:56 2010 +0100
> +++ b/tools/libxl/libxl.c       Fri Aug 27 18:27:27 2010 +0100
> @@ -127,7 +127,7 @@ int libxl_domain_make(libxl_ctx *ctx, li
>      *domid = -1;
>
>      /* Ultimately, handle is an array of 16 uint8_t, same as uuid */
> -    memcpy(handle, info->uuid, sizeof(xen_domain_handle_t));
> +    libxl_uuid_copy((libxl_uuid *)handle, &info->uuid);
>
>      ret = xc_domain_create(ctx->xch, info->ssidref, handle, flags,
domid);
>      if (ret < 0) {
> @@ -1502,8 +1502,8 @@ static int libxl_create_stubdom(libxl_ct
>      memset(&c_info, 0x00, sizeof(libxl_domain_create_info));
>      c_info.hvm = 0;
>      c_info.name = libxl_sprintf(&gc, "%s-dm",
_libxl_domid_to_name(&gc,
> info->domid)); -    for (i = 0; i < 16; i++)
> -        c_info.uuid[i] = info->uuid[i];
> +
> +    libxl_uuid_copy(&c_info.uuid, &info->uuid);
>
>      memset(&b_info, 0x00, sizeof(libxl_domain_build_info));
>      b_info.max_vcpus = 1;
> diff -r 3c4c3d48a835 tools/libxl/libxl.h
> --- a/tools/libxl/libxl.h       Thu Aug 26 11:16:56 2010 +0100
> +++ b/tools/libxl/libxl.h       Fri Aug 27 18:27:27 2010 +0100
> @@ -131,13 +131,7 @@
>  #include <xs.h>
>  #include <sys/wait.h> /* for pid_t */
>
> -typedef uint8_t libxl_uuid[16];
> -#define LIBXL_UUID_FMT
>
"%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02h
>hx%02hhx%02hhx%02hhx%02hhx" -#define LIBXL_UUID_BYTES(uuid) uuid[0],
> uuid[1], uuid[2], uuid[3], \ -            uuid[4], uuid[5], uuid[6],
> uuid[7], \
> -            uuid[8], uuid[9], uuid[10], uuid[11], \
> -            uuid[12], uuid[13], uuid[14], uuid[15] \
> -
> +#include "libxl_uuid.h"
>
>  typedef uint8_t libxl_mac[6];
>
> diff -r 3c4c3d48a835 tools/libxl/libxl_uuid.h
> --- /dev/null   Thu Jan 01 00:00:00 1970 +0000
> +++ b/tools/libxl/libxl_uuid.h  Fri Aug 27 18:27:27 2010 +0100
> @@ -0,0 +1,156 @@
> +/* Copyright (c) 2008, XenSource Inc.
> + * All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions are
> met: + *     * Redistributions of source code must retain the above
> copyright + *     notice, this list of conditions and the following
> disclaimer. + *     * Redistributions in binary form must reproduce the
> above copyright + *     notice, this list of conditions and the following
> disclaimer in the + *     documentation and/or other materials provided
> with the distribution. + *     * Neither the name of XenSource Inc. nor the
> names of its contributors + *     may be used to endorse or promote
> products derived from this software + *     without specific prior written
> permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
NOT
> + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> OWNER + * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> +*/
> +#ifndef __LIBXL_UUID_H__
> +#define __LIBXL_UUID_H__
> +
> +#define LIBXL_UUID_FMT
>
"%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02h
>hx%02hhx%02hhx%02hhx%02hhx" +
> +#if defined(__linux__)
> +
> +#include <uuid/uuid.h>
> +
> +typedef struct {
> +    uuid_t uuid;
> +} libxl_uuid;
> +
> +#define LIBXL__UUID_BYTES(uuid) uuid[0], uuid[1], uuid[2], uuid[3], \
> +                                uuid[4], uuid[5], uuid[6], uuid[7], \
> +                                uuid[8], uuid[9], uuid[10], uuid[11], \
> +                                uuid[12], uuid[13], uuid[14], uuid[15]
> +#define LIBXL_UUID_BYTES(arg) LIBXL__UUID_BYTES(((uint8_t *)arg.uuid))
> +
> +static inline int libxl_uuid_is_nil(libxl_uuid *uuid)
> +{
> +     return uuid_is_null(uuid->uuid);
> +}
> +
> +static inline void libxl_uuid_generate(libxl_uuid *uuid)
> +{
> +     uuid_generate(uuid->uuid);
> +}
> +
> +static inline void libxl_uuido_string(libxl_uuid *uuid, char *out, size_t
> size) +{
> +     uuid_unparse(uuid->uuid, out);
> +}
> +
> +static inline int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
> +{
> +     return uuid_parse(in, uuid->uuid);
> +}
> +
> +static inline void libxl_uuid_copy(libxl_uuid *dst, libxl_uuid *src)
> +{
> +     uuid_copy(dst->uuid, src->uuid);
> +}
> +
> +static inline void libxl_uuid_clear(libxl_uuid *uuid)
> +{
> +     uuid_clear(uuid->uuid);
> +}
> +
> +static inline int libxl_uuid_compare(libxl_uuid *uuid1, libxl_uuid *uuid2)
> +{
> +     return uuid_compare(uuid1->uuid, uuid2->uuid);
> +}
> +
> +static inline const uint8_t *libxl_uuid_bytearray(libxl_uuid *uuid)
> +{
> +    return uuid->uuid;
> +}
> +
> +#elif defined(__NetBSD__)
> +
> +#include <uuid.h>
> +#include <string.h>
> +#include <stdlib.h>
> +
> +typedef uuid_t libxl_uuid;
> +#define LIBXL__UUID_BYTES(uuid) uuid[0], uuid[1], uuid[2], uuid[3], \
> +                                uuid[4], uuid[5], uuid[6], uuid[7], \
> +                                uuid[8], uuid[9], uuid[10], uuid[11], \
> +                                uuid[12], uuid[13], uuid[14], uuid[15]
> +#define LIBXL_UUID_BYTES(uuid) LIBXL__UUID_BYTES(((uint8_t *)uuid))
> +
> +static inline int libxl_uuid_is_nil(libxl_uuid *uuid)
> +{
> +     uint32_t status;
> +     return uuid_is_nil((uuid_t *)uuid, &status);
> +}
> +
> +static inline void libxl_uuid_generate(libxl_uuid *uuid)
> +{
> +     uint32_t status;
> +     uuid_create((uuid_t *)uuid, &status);
> +}
> +
> +static inline void libxl_uuido_string(libxl_uuid *uuid, char *out, size_t
> size) +{
> +     uint32_t status;
> +     char *_out = NULL;
> +     uuid_to_string((uuid_t *)uuid, &_out, &status);
> +     strlcpy(out, _out, size);
> +     free(_out);
> +}
> +
> +static inline int libxl_uuid_from_string(libxl_uuid *uuid, const char *in)
> +{
> +    uint32_t status;
> +    uuid_from_string(in, (uuid_t *)uuid, &status);
> +    if ( status != uuid_s_ok )
> +        return -1;
> +    return 0;
> +}
> +
> +static inline void libxl_uuid_copy(libxl_uuid *dst, libxl_uuid *src)
> +{
> +     memcpy((uuid_t *)dst, (uuid_t *)src, sizeof(uuid_t));
> +}
> +
> +static inline void libxl_uuid_clear(libxl_uuid *uuid)
> +{
> +     memset((uuid_t *)uuid, 0, sizeof(uuid_t));
> +}
> +
> +static inline int libxl_uuid_compare(libxl_uuid *uuid1, libxl_uuid *uuid2)
> +{
> +     uint32_t status;
> +     return uuid_compare((uuid_t *)uuid1, (uuid_t *)uuid2, &status);
> +}
> +
> +static inline const uint8_t *libxl_uuid_bytearray(libxl_uuid *uuid)
> +{
> +    return uuid;
> +}
> +
> +#else
> +
> +#error "Please update libxl_uuid.h for your OS"
> +
> +#endif
> +
> +#endif /* __LIBXL_UUID_H__ */
> diff -r 3c4c3d48a835 tools/libxl/xl.c
> --- a/tools/libxl/xl.c  Thu Aug 26 11:16:56 2010 +0100
> +++ b/tools/libxl/xl.c  Fri Aug 27 18:27:27 2010 +0100
> @@ -74,8 +74,6 @@ int main(int argc, char **argv)
>      argc -= optind;
>      optind = 1;
>
> -    srand(time(0));
> -
>      cspec = cmdtable_lookup(cmd);
>      if (cspec)
>          ret = cspec->cmd_impl(argc, argv);
> diff -r 3c4c3d48a835 tools/libxl/xl_cmdimpl.c
> --- a/tools/libxl/xl_cmdimpl.c  Thu Aug 26 11:16:56 2010 +0100
> +++ b/tools/libxl/xl_cmdimpl.c  Fri Aug 27 18:27:27 2010 +0100
> @@ -286,19 +286,12 @@ static void init_build_info(libxl_domain
>      }
>  }
>
> -static void random_uuid(libxl_uuid *uuid)
> -{
> -    int i;
> -    for (i = 0; i < 16; i++)
> -        (*uuid)[i] = rand();
> -}
> -
>  static void init_dm_info(libxl_device_model_info *dm_info,
>          libxl_domain_create_info *c_info, libxl_domain_build_info *b_info)
>  {
>      memset(dm_info, ''\0'', sizeof(*dm_info));
>
> -    random_uuid(&dm_info->uuid);
> +    libxl_uuid_generate(&dm_info->uuid);
>
>      dm_info->dom_name = c_info->name;
>      dm_info->device_model = "qemu-dm";
> @@ -325,6 +318,11 @@ static void init_dm_info(libxl_device_mo
>
>  static void init_nic_info(libxl_device_nic *nic_info, int devnum)
>  {
> +    const uint8_t *r;
> +    libxl_uuid uuid;
> +
> +    libxl_uuid_generate(&uuid);
> +    r = libxl_uuid_bytearray(&uuid);
>      memset(nic_info, ''\0'', sizeof(*nic_info));
>
>      nic_info->backend_domid = 0;
> @@ -335,9 +333,9 @@ static void init_nic_info(libxl_device_n
>      nic_info->mac[0] = 0x00;
>      nic_info->mac[1] = 0x16;
>      nic_info->mac[2] = 0x3e;
> -    nic_info->mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX + 1.0)));
> -    nic_info->mac[4] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
> -    nic_info->mac[5] = 1 + (int) (0xff * (rand() / (RAND_MAX + 1.0)));
> +    nic_info->mac[3] = r[0] & 0x7f;
> +    nic_info->mac[4] = r[1];
> +    nic_info->mac[5] = r[2];
>      nic_info->ifname = NULL;
>      nic_info->bridge = strdup("xenbr0");
>      CHK_ERRNO( asprintf(&nic_info->script,
"%s/vif-bridge",
> @@ -347,21 +345,26 @@ static void init_nic_info(libxl_device_n
>
>  static void init_net2_info(libxl_device_net2 *net2_info, int devnum)
>  {
> +    const uint8_t *r;
> +    libxl_uuid uuid;
> +
> +    libxl_uuid_generate(&uuid);
> +    r = libxl_uuid_bytearray(&uuid);
>      memset(net2_info, ''\0'', sizeof(*net2_info));
>
>      net2_info->devid = devnum;
>      net2_info->front_mac[0] = 0x00;
>      net2_info->front_mac[1] = 0x16;
>      net2_info->front_mac[2] = 0x3e;;
> -    net2_info->front_mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX +
> 1.0))); -    net2_info->front_mac[4] = 1 + (int) (0xff * (rand() /
> (RAND_MAX + 1.0))); -    net2_info->front_mac[5] = 1 + (int) (0xff *
> (rand() / (RAND_MAX + 1.0))); +    net2_info->front_mac[3] = 0x7f &
r[0];
> +    net2_info->front_mac[4] = r[1];
> +    net2_info->front_mac[5] = r[2];
>      net2_info->back_mac[0] = 0x00;
>      net2_info->back_mac[1] = 0x16;
>      net2_info->back_mac[2] = 0x3e;
> -    net2_info->back_mac[3] = 1 + (int) (0x7f * (rand() / (RAND_MAX +
> 1.0))); -    net2_info->back_mac[4] = 1 + (int) (0xff * (rand() /
(RAND_MAX
> + 1.0))); -    net2_info->back_mac[5] = 1 + (int) (0xff * (rand() /
> (RAND_MAX + 1.0))); +    net2_info->back_mac[3] = 0x7f & r[3];
> +    net2_info->back_mac[4] = r[4];
> +    net2_info->back_mac[5] = r[5];
>      net2_info->back_trusted = 1;
>      net2_info->filter_mac = 1;
>      net2_info->max_bypasses = 5;
> @@ -604,7 +607,10 @@ static void parse_config_data(const char
>          c_info->name = strdup(buf);
>      else
>          c_info->name = "test";
> -    random_uuid(&c_info->uuid);
> +
> +    if (!xlu_cfg_get_string (config, "uuid", &buf) ||
> +        libxl_uuid_from_string(&c_info->uuid, buf) )
> +        libxl_uuid_generate(&c_info->uuid);
>
>      if (!xlu_cfg_get_long(config, "oos", &l))
>          c_info->oos = l;
> @@ -1206,7 +1212,7 @@ static int preserve_domain(libxl_ctx *ct
>          return 0;
>      }
>
> -    random_uuid(&new_uuid);
> +    libxl_uuid_generate(&new_uuid);
>
>      LOG("Preserving domain %d %s with suffix%s", domid,
> d_config->c_info.name, stime); rc = libxl_domain_preserve(ctx, domid,
> &d_config->c_info, stime, new_uuid);