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bug#35714: Parted destroys mbr_signature (Disk Identifier) when adding M
From: |
Matthijs Kooijman |
Subject: |
bug#35714: Parted destroys mbr_signature (Disk Identifier) when adding MBR bootcode |
Date: |
Mon, 13 May 2019 16:30:32 +0200 |
User-agent: |
NeoMutt/20170113 (1.7.2) |
Hi folks,
one more addition: Below is an example of reproducing this problem on an
Ubuntu Disco system running parted 3.2-25. I haven't tried git master,
but looking at the code, I'm pretty sure the problem stil exists there.
Gr.
Matthijs
# Use fdisk to create an empty partition table without any boot code
address@hidden:~$ truncate -s 8M tmp.img
address@hidden:~$ echo -e 'o\nw' | fdisk tmp.img
Welcome to fdisk (util-linux 2.33.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x0298967f.
Command (m for help): Created a new DOS disklabel with disk identifier
0x94bfb6ca.
Command (m for help): The partition table has been altered.
Syncing disks.
address@hidden:~$ fdisk -l tmp.img | grep identifier
Disk identifier: 0x94bfb6ca
address@hidden:~$ head -c 512 tmp.img | hd
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001b0 00 00 00 00 00 00 00 00 ca b6 bf 94 00 00 00 00 |................|
000001c0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200
# Then use parted to add a partition
address@hidden:~$ parted tmp.img mkpart p fat32 4096s 8191s
/sys/firmware/dmi/tables/smbios_entry_point: Permission denied
/dev/mem: Permission denied
WARNING: You are not superuser. Watch out for permissions.
# This has changed the disk identifier (and added bootcode)
address@hidden:~$ fdisk -l tmp.img | grep identifier
Disk identifier: 0x5d7de418
address@hidden:~$ head -c 512 tmp.img | hd
00000000 fa b8 00 10 8e d0 bc 00 b0 b8 00 00 8e d8 8e c0 |................|
00000010 fb be 00 7c bf 00 06 b9 00 02 f3 a4 ea 21 06 00 |...|.........!..|
00000020 00 be be 07 38 04 75 0b 83 c6 10 81 fe fe 07 75 |....8.u........u|
00000030 f3 eb 16 b4 02 b0 01 bb 00 7c b2 80 8a 74 01 8b |.........|...t..|
00000040 4c 02 cd 13 ea 00 7c 00 00 eb fe 00 00 00 00 00 |L.....|.........|
00000050 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001b0 00 00 00 00 00 00 00 00 18 e4 7d 5d 00 00 00 00 |..........}]....|
000001c0 01 20 0c 03 20 3f 00 10 00 00 00 10 00 00 00 00 |. .. ?..........|
000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200
signature.asc
Description: PGP signature