Pull hardening updates from Kees Cook:

 - lib/string_choices:
    - Add str_up_down() helper (Michal Wajdeczko)
    - Add str_true_false()/str_false_true() helper  (Hongbo Li)
    - Introduce several opposite string choice helpers  (Hongbo Li)

 - lib/string_helpers:
    - rework overflow-dependent code (Justin Stitt)

 - fortify: refactor test_fortify Makefile to fix some build problems
   (Masahiro Yamada)

 - string: Check for "nonstring" attribute on strscpy() arguments

 - virt: vbox: Replace 1-element arrays with flexible arrays

 - media: venus: hfi_cmds: Replace 1-element arrays with flexible arrays

* tag 'hardening-v6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  lib/string_choices: Add some comments to make more clear for string choices helpers.
  lib/string_choices: Introduce several opposite string choice helpers
  lib/string_choices: Add str_true_false()/str_false_true() helper
  string: Check for "nonstring" attribute on strscpy() arguments
  media: venus: hfi_cmds: struct hfi_session_release_buffer_pkt: Add __counted_by annotation
  media: venus: hfi_cmds: struct hfi_session_release_buffer_pkt: Replace 1-element array with flexible array
  virt: vbox: struct vmmdev_hgcm_pagelist: Replace 1-element array with flexible array
  lib/string_helpers: rework overflow-dependent code
  coccinelle: Add rules to find str_down_up() replacements
  string_choices: Add wrapper for str_down_up()
  coccinelle: Add rules to find str_up_down() replacements
  lib/string_choices: Add str_up_down() helper
  fortify: use if_changed_dep to record header dependency in *.cmd files
  fortify: move test_fortify.sh to lib/test_fortify/
  fortify: refactor test_fortify Makefile to fix some build problems