[Bug 1877089] Re: zfcpdump kernel can not be IPLed, wrong file name

[Dimitri John Ledkov]

On Tue, Nov 3, 2020 at 10:15 PM Brian Murray <1877089 at bugs.launchpad.net>
wrote:

> Could somebody address Robie's remaining questions in comment #15?
>
>
Rovies' questions got address the same day.

Upload was made to groovy.

This kernel image has no relationship to the running OS, it is a kdump-like
kernel image, which firmware (HMC) loads whilst all processes and execution
is stopped. Thus is independent from the OS/kernel/userspace that is being
dumped.

However, the filenames in the package must be compatible with the userspace
tooling to prepare firmware to load this kernel.

Jump to v5.4 is because 4.15 will go end of life and out of support, whilst
focal one will remain. Nonetheless it is not expected that there will be
further updates to the zfcpdump kernel, the config of this kernel flavour
is tiny and doesn't have network access thus is hard to exploit, and it is
not signed for secureboot.

-- 
Regards,

Dimitri.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to s390-tools in Ubuntu.
https://bugs.launchpad.net/bugs/1877089

Title:
  zfcpdump kernel can not be IPLed, wrong file name

Status in Ubuntu on IBM z Systems:
  In Progress
Status in s390-tools package in Ubuntu:
  Invalid
Status in zfcpdump-kernel package in Ubuntu:
  Fix Released
Status in zfcpdump-kernel source package in Focal:
  Confirmed
Status in zfcpdump-kernel source package in Groovy:
  Fix Released

Bug description:
  [Impact]

   * zfcpdump-kernel incompatible with s390-tools in focal, due to wrong file name, needed in focal and up
   * zfcpdump-kernel incompatible with SIPL (secure IPL), and will not be fixed.

   * Upgrade to the v5.4 kernel
   * Signing will not be enabled
   * Update the path of the image, to the one that `zipl -d` in focal expects

  [Test Case]

   * Prepare sda1 drive for SCSI dump
   * Stop all processes from the HMC
   * Perform SCSI dump load from HMC
   * Observe that dump is successful and used v5.4 kernel from the Operating System Messages
   * Perform regular boot
   * Mount the dump, and observe it is there in full

   * Can be performed on the canonical z13 hmc without SIPL
   * zfcpdump with secureboot will not be possible

  [Publication]

   * zfcpdump-kernel image is OS series independant, and thus can be
  build in focal with copies up to groovy.

  [Regression Potential]

   * The kernel image used for zfcpdump is fairly static, doesn't have
  loadable modules, but it does allow reading kernel memory which in
  theory is not in the same spirit as lockdown. However, stopping all
  processes and triggering scsi-dump is a priviledged HMC operation that
  is otheriwse has a much higher access restrictions than lockdown can
  provide.

  [Other Info]

   * Original bug report

  I installed Ubuntu 20.04 on IBM z15 with secure=1 in zipl conf.
  System can be secure booted, /sys/firmware/ipl/secure shows "1".
  I prepared zfcp dump disk as described in LTC bug 185713.
  Stopped the system and performed a SCSI dump with "Enable Secure Boot for Linux" enabled.

  Operating System Messages on HMC:
  Preparing system.
  Starting system.
  System version 8.
  Watchdog enabled.
  Running 'ZBootLoader' version '1.0.0' level 'D41C.D41C_0014'.
  ZBootLoader 2.1.0.
  MLOLOA6269064E Secure IPL: There are no signed components available on device HB
  A=0.0.1800, WWPN=500507630309D327, LUN=4046400900000000.
  IPL failed.

  Without "Enable Secure Boot for Linux" the dump kernel was IPLed and a
  dump created.

  Then I tried to rewrite the zfcp dump kernel with explicite setting of --secure=1:
  root at t35lp25:~# zipl --secure=1 -d /dev/disk/by-id/scsi-36005076303ffd3270000000000004609-part1
  Building bootmap directly on partition '/dev/disk/by-id/scsi-36005076303ffd3270000000000004609-part1'
  Adding dump section
    initial ramdisk...: /lib/s390-tools/zfcpdump/zfcpdump-initrd
    kernel image......: /lib/s390-tools/zfcpdump/zfcpdump-image
    kernel parmline...: 'root=/dev/ram0 dump_mem=1 possible_cpus=1 cgroup_disable=memory '
    component address:
      heap area.......: 0x00002000-0x00005fff
      stack area......: 0x0000f000-0x0000ffff
      internal loader.: 0x0000a000-0x0000dfff
      parameters......: 0x00009000-0x000091ff
      kernel image....: 0x00010000-0x001b9fff
      parmline........: 0x001ba000-0x001ba1ff
      initial ramdisk.: 0x001c0000-0x0020edff
  Preparing boot device: sde.
  Done.

  ...and tried to SCSI dump this device again. But the same  failure occured.
  Again, without "Enable Secure Boot for Linux" the dump kernel was IPLed and a dump created.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu-z-systems/+bug/1877089/+subscriptions