[Bug 1983359] Re: [SRU] hwrng drivers missing in initrd.img

[Heinrich Schuchardt]

I tested the fix on Jammy successfully:

On top of ubuntu-22.04.1-preinstalled-server-riscv64+unmatched.img.xz I
installed

initramfs-tools-bin_0.140ubuntu13.2_riscv64.deb
initramfs-tools-core_0.140ubuntu13.2_all.deb
initramfs-tools_0.140ubuntu13.2_all.deb

from jammy-proposed.

The initrd contained 
lib/modules/5.15.0-1016-generic/kernel/drivers/char/hw_random/virtio-rng.ko
and other RNG drivers.

The system rebooted without problems.

sudo dmesg | grep 'uninitialized urandom'

returned no record.

** Tags removed: verification-needed verification-needed-jammy
** Tags added: verification-done verification-done-jammy

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Title:
  [SRU] hwrng drivers missing in initrd.img

Status in initramfs-tools package in Ubuntu:
  Fix Released
Status in initramfs-tools source package in Jammy:
  Fix Committed
Status in initramfs-tools source package in Kinetic:
  Fix Released

Bug description:
  [Impact]

  The initialization of the entropy buffer of the urandom device is
  critical for security.

  When booting Jammy 22.04.1 on QEMU riscv64 I see the following
  warnings:

  [   14.654546] random: lvm: uninitialized urandom read (4 bytes read)
  [   15.247995] random: lvm: uninitialized urandom read (2 bytes read)
  [   22.484719] random: lvm: uninitialized urandom read (4 bytes read)
  [   43.161846] random: lvmconfig: uninitialized urandom read (4 bytes read)
  [   48.862281] random: lvm: uninitialized urandom read (4 bytes read)

  Module virtio-rng.ko is missing in initrd.img.
  Adding virtio_rng to /etc/initramfs-tools/modules avoids the warnings.

  Hardware RNG drivers should generally be included in the initrd to
  provide early entropy.

  [Test case]

  To reproduce the issue:

  Install the prerequisites:
  sudo apt-get update
  sudo apt-get install opensbi qemu-system-misc u-boot-qemu

  Download https://old-
  releases.ubuntu.com/releases/22.04.1/ubuntu-22.04.1-preinstalled-
  server-riscv64+unmatched.img.xz.

  Decompress it with
  xz -d ubuntu-22.04.1-preinstalled-server-riscv64+unmatched.img.xz

  Run it in QEMU with

  qemu-system-riscv64 \
  -machine virt -nographic -m 2048 -smp 4 \
  -bios /usr/lib/riscv64-linux-gnu/opensbi/generic/fw_jump.bin \
  -kernel /usr/lib/u-boot/qemu-riscv64_smode/uboot.elf \
  -device virtio-net-device,netdev=eth0 -netdev user,id=eth0 \
  -device virtio-rng-pci \
  -drive file=ubuntu-22.04.1-preinstalled-server-riscv64+unmatched.img,format=raw,if=virtio

  You can log into the system with user ubuntu, password ubuntu after
  seeing the message "Cloud-init v. 22.2-0ubuntu1~22.04.3 finished"

  Run 'sudo dmesg | grep 'uninitialized urandom'

  To test the fix:

  Update the initramfs-tools package.

  Run 'update-initramfs -k $(uname -r) -u' with MODULES=most (defined in
  /etc/initramfs-tools/initramfs.conf or in /etc/initramfs-
  tools/conf.d/*.conf)

  Unpack the initrd with 'unmkinitramfs /boot/initrd.img-$(uname -r)'

  Check that [main/]lib/modules/$(uname
  -r)/kernel/drivers/char/hw_random/ exists and contains kernel modules.
  When running on QEMU the relevant module is virtio-rng.ko.

  Reboot and check the kernel log by running 'sudo dmesg | grep
  'uninitialized urandom'.

  [Where problems could occur]

  Adding more drivers increases the size of the initrd. The larger
  initrd might not fit onto the boot partition. The total size of
  hw_random drivers on amd64 is less than 150 KiB so this seem
  improbable.

  [Other Info]

  n/a

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