From bf9dd867ef8d4164685cac6451e88b6c32b190b1 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Mon, 15 Feb 2016 09:28:15 +0100 Subject: [PATCH 02/18] vmdk: Use g_random_int to generate CID MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Fam Zheng Message-id: <1455528511-9357-3-git-send-email-famz@redhat.com> Patchwork-id: 69168 O-Subject: [RHEL-7.3 qemu-kvm PATCH 02/18] vmdk: Use g_random_int to generate CID Bugzilla: 1299250 RH-Acked-by: Kevin Wolf RH-Acked-by: Max Reitz RH-Acked-by: Markus Armbruster BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1299250 This replaces two "time(NULL)" invocations with "g_random_int()". According to VMDK spec, CID "is a random 32‐bit value updated the first time the content of the virtual disk is modified after the virtual disk is opened". Using "seconds since epoch" is just a "lame way" to generate it, and not completely safe because of the low precision. Suggested-by: Markus Armbruster Signed-off-by: Fam Zheng Reviewed-by: Markus Armbruster Reviewed-by: Don Koch Reviewed-by: Max Reitz Message-id: 1417649314-13704-2-git-send-email-famz@redhat.com Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf (cherry picked from commit e5dc64b8ff09cc4c186273e4461c7479739db2ae) Signed-off-by: Fam Zheng Signed-off-by: Miroslav Rezanina --- block/vmdk.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/block/vmdk.c b/block/vmdk.c index fa53d2f..a9f5bab 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -28,6 +28,7 @@ #include "qemu/module.h" #include "migration/migration.h" #include +#include #define VMDK3_MAGIC (('C' << 24) | ('O' << 16) | ('W' << 8) | 'D') #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V') @@ -1540,7 +1541,7 @@ static int vmdk_write(BlockDriverState *bs, int64_t sector_num, /* update CID on the first write every time the virtual disk is * opened */ if (!s->cid_updated) { - ret = vmdk_write_cid(bs, time(NULL)); + ret = vmdk_write_cid(bs, g_random_int()); if (ret < 0) { return ret; } @@ -1927,7 +1928,7 @@ static int vmdk_create(const char *filename, QEMUOptionParameter *options, } /* generate descriptor file */ desc = g_strdup_printf(desc_template, - (uint32_t)time(NULL), + g_random_int(), parent_cid, fmt, parent_desc_line, -- 1.8.3.1