[PATCH v4 0/6] initramfs: test and improve cpio hex header validation

[David Disseldorp <ddiss@suse.de>]

Changes v4:
- rework initramfs_test changes to use an inject_ox parameter instead of
  having tests pass through an unvalidated format string.
  + drop Andy's reviewed-by from 1/6 and 2/6 to account for changed test
  + 4/6 minor changes for test context and comment
- add review tags for 3/6, 5/6 and 6/6 following list feedback

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v3: 20260323150054.3587083-1-andriy.shevchenko@linux.intel.com

The series that introduced simple_strntoul() had passed into kernel
without proper review and hence reinvented a wheel that's not needed.
Here is the refactoring to show that. It can go via PRINTK or VFS
tree.

I have tested this on x86, but I believe the same result will be
on big-endian CPUs (I deduced that from how strtox() works).

I also run KUnit tests.

Changelog v3:
- rebased on top of latest kernel
- squashed patches proposed by David

v2: 20260121172749.32322-1-ddiss@suse.de
v1: 20260119204151.1447503-1-andriy.shevchenko@linux.intel.com

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Andy Shevchenko (4):
      initramfs: Sort headers alphabetically
      initramfs: Refactor to use hex2bin() instead of custom approach
      vsprintf: Revert "add simple_strntoul"
      kstrtox: Drop extern keyword in the simple_strtox() declarations

David Disseldorp (2):
      initramfs_test: add fill_cpio() inject_ox parameter
      initramfs_test: test header fields with 0x hex prefix

 include/linux/kstrtox.h |  9 +++--
 init/initramfs.c        | 68 ++++++++++++++++++++----------------
 init/initramfs_test.c   | 76 ++++++++++++++++++++++++++++++++++-------
 lib/vsprintf.c          |  7 ----
 4 files changed, 105 insertions(+), 55 deletions(-)