[Bug 2154120] Re: [SRU] gpg buggy on RISC-V when vector length /= 128B

[Valentin Haudiquet]

Can confirm that the upstream commit fixes the issue.
Fix is available for stonking in ppa: 

https://launchpad.net/~vhaudiquet/+archive/ubuntu/lp2154120-gpg/+packages

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https://bugs.launchpad.net/bugs/2154120

Title:
  [SRU] gpg buggy on RISC-V when vector length /= 128B

Status in gnupg2 package in Ubuntu:
  Invalid
Status in libgcrypt20 package in Ubuntu:
  In Progress
Status in gnupg2 source package in Questing:
  Invalid
Status in libgcrypt20 source package in Questing:
  Invalid
Status in gnupg2 source package in Resolute:
  Invalid
Status in libgcrypt20 source package in Resolute:
  In Progress
Status in gnupg2 source package in Stonking:
  Invalid
Status in libgcrypt20 source package in Stonking:
  In Progress

Bug description:
  [ Impact ]

  GPG is broken on RISC-V when vector length (VLEN) doesn't equal 128B.

  This has been fixed upstream:
  https://github.com/gpg/libgcrypt/commit/3f684fc6ab3ac98320e245a06b3563ad37ec56f5

  The upload backports the upstream commit as debian patch.

  [ Test Plan ]

  Start a RISC-V VM with QEMU, setting vector length to >128.

  For this, check

  https://documentation.ubuntu.com/hardware-support/boards/how-
  to/ubuntu_supported/qemu-riscv/

  for the full command, and modify it to set vlen:

  qemu-system-riscv64 -cpu max,vlen=256 ...

  Then, in the VM, run the following commands:

  head -c 10000 /dev/urandom > in.bin
  PW="testpw-correct-horse-battery-staple"
  gpg --batch --pinentry-mode loopback --passphrase "$PW" --yes --symmetric \
      --cipher-algo AES256 --output out.gpg in.bin
  gpg --batch --pinentry-mode loopback --passphrase "$PW" --yes \
     --decrypt --output dec.bin out.gpg

  This should succeed with only a success message from gpg. However, it
  currently returns:

  gpg: AES256.CFB encrypted data
  gpg: encrypted with 1 passphrase
  gpg: WARNING: encrypted message has been manipulated!

  It might also be useful to check that basic GPG functionality still
  works.

  [ Where problems could occur ]

  Given that this is a change in a library used by GPG, we need to make
  sure that basic GPG features still work, or that could introduce
  issues around apt and any other GPG user.

  [ Other Info ]

  Only Resolute and Stonking are affected. Questing does not have the
  bug. Plucky, Noble and below do not have RISC-V vector support.

  Original bug report:

  GPG is broken on RISC-V when vector length (VLEN) doesn't equal 128B.

  This has been fixed upstream:
  https://github.com/gpg/libgcrypt/commit/3f684fc6ab3ac98320e245a06b3563ad37ec56f5

  Test:

  head -c 10000 /dev/urandom > in.bin
  PW="testpw-correct-horse-battery-staple"
  gpg --batch --pinentry-mode loopback --passphrase "$PW" --yes --symmetric \
      --cipher-algo AES256 --output out.gpg in.bin
  gpg --batch --pinentry-mode loopback --passphrase "$PW" --yes \
     --decrypt --output dec.bin out.gpg
  if cmp -s in.bin dec.bin; then
    echo "PASS encrypt/decrypt"
  else
    echo "MISMATCH"
  fi

  Run this on x86 it works fine but run it on SpacemiT K3 with VLEN=256
  it fails.

  ProblemType: Bug
  DistroRelease: Ubuntu 26.04
  Package: gpg 2.4.8-4ubuntu3
  Uname: Linux 6.18.3-5-spacemit-generic riscv64
  ApportVersion: 2.34.0-0ubuntu2
  Architecture: riscv64
  CasperMD5CheckResult: unknown
  CloudArchitecture: riscv64
  CloudID: nocloud
  CloudName: unknown
  CloudPlatform: nocloud
  CloudSubPlatform: config-disk (/dev/sda2)
  Date: Sun May 24 10:40:29 2026
  ProcEnviron:
   LANG=C.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=tmux-256color
   XDG_RUNTIME_DIR=<set>
  SourcePackage: gnupg2
  UpgradeStatus: No upgrade log present (probably fresh install)

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