Bug 1326474

Description of problem:

Wipefs doesn't appear to see all of the partition maps in this hybrid map used by Fedora installation ISOs. It sees and wipes the MBR and APM signatures, but leaves the GPT signature intact.



Version-Release number of selected component (if applicable):
util-linux-2.27.1-2.fc23.x86_64

How reproducible:
Always

Steps to Reproduce:
1. dd if=<any Fedora ISO> of=<USB flash> bs=1M count=20
2. wipefs -a /dev/sdb[123] 
3. wipefs -a /dev/sdb


Actual results:


# wipefs -a /dev/sdb[123]
/dev/sdb1: 5 bytes were erased at offset 0x00008001 (iso9660): 43 44 30 30 31
wipefs: /dev/sdb1: ignoring nested "dos" partition table on non-whole disk device
wipefs: /dev/sdb1: ignoring nested "mac" partition table on non-whole disk device
wipefs: Use the --force option to force erase.
/dev/sdb2: 8 bytes were erased at offset 0x00000036 (vfat): 46 41 54 31 32 20 20 20
/dev/sdb2: 1 byte was erased at offset 0x00000000 (vfat): eb
/dev/sdb2: 2 bytes were erased at offset 0x000001fe (vfat): 55 aa
/dev/sdb3: 2 bytes were erased at offset 0x00000400 (hfsplus): 48 2b

# wipefs -a /dev/sdb
/dev/sdb: 2 bytes were erased at offset 0x000001fe (dos): 55 aa
/dev/sdb: 2 bytes were erased at offset 0x00000000 (mac): 45 52
/dev/sdb: calling ioctl to re-read partition table: Success

# parted /dev/sdb u s p
Error: /dev/sdb: unrecognised disk label
Model: Kingston DT R500 (scsi)                                            
Disk /dev/sdb: 31277056s
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags: 

# gdisk -l /dev/sdb
GPT fdisk (gdisk) version 1.0.1

Partition table scan:
  MBR: not present
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with corrupt MBR; using GPT and will write new
protective MBR on save.
Warning! Main partition table overlaps the first partition by 48 blocks!
You will need to delete this partition or resize it in another utility.
Disk /dev/sdb: 31277056 sectors, 14.9 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 93475653-E08A-4F1E-B3B0-D325D32C6283
Partition table holds up to 128 entries
First usable sector is 48, last usable sector is 2873310
Partitions will be aligned on 4-sector boundaries
Total free space is 1539 sectors (769.5 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   2          102844          113479   5.2 MiB     0700  ISOHybrid
   3          113480          136823   11.4 MiB    AF00  ISOHybrid




Expected results:

gdisk shouldn't see this as a valid GPT; I can't tell off hand if this is a valid GPT, but wipefs hasn't tried to wipe the GPT signature. It looks like at offset 0x200 these 8 bytes should be removed 45 46 49 20 50 41 52 54.

Even though this GPT is half broken due to missing backup GPT, the primary seems valid still? So it probably should have the signature wiped.

Additional info:

I used Fedora-Workstation-Live-x86_64-24_Alpha-7.iso for this test.


/dev/sdb1: UUID="2016-03-22-21-57-41-00" LABEL="Fedora-WS-Live-24_A-7" TYPE="iso9660" PTUUID="08549cf5" PTTYPE="dos" PARTUUID="08549cf5-01"
/dev/sdb2: SEC_TYPE="msdos" LABEL="ANACONDA" UUID="FC75-9AAF" TYPE="vfat" PARTUUID="08549cf5-02"
/dev/sdb3: UUID="b5a043c2-e705-30c1-ae04-3e45bd601a39" LABEL="ANACONDA" TYPE="hfsplus" PARTUUID="08549cf5-03"


# wipefs -np /dev/sdb[123]
# offset,uuid,label,type
0x0,,,mac
0x1fe,,,dos
0x8001,2016-03-22-21-57-41-00,Fedora-WS-Live-24_A-7,iso9660
# offset,uuid,label,type
0x36,FC75-9AAF,ANACONDA,vfat
# offset,uuid,label,type
0x400,b5a043c2-e705-30c1-ae04-3e45bd601a39,ANACONDA,hfsplus


# wipefs -np /dev/sdb
# offset,uuid,label,type
0x0,,,mac
0x1fe,,,dos
0x8001,2016-03-22-21-57-41-00,Fedora-WS-Live-24_A-7,iso9660