[PATCH v2 0/3] platform/x86: hp-bioscfg: string buffer and password fixes

[Muhammad Bilal <meatuni001@gmail.com>]

This series addresses string buffer issues and password validation
in the hp-bioscfg driver.

Patch 1 fixes bounds checking, prescan OOB read, and character count
accounting in hp_get_string_from_buffer().

Patch 2 replaces the truncating manual conversion loop with a two-stage
conversion: utf16s_to_utf8s() into a scratch buffer followed by
string_escape_mem().

Patch 3 fixes validate_password_input() returning positive
INVALID_BIOS_AUTH (0x0E), which caused userspace writes of
out-of-range passwords to appear successful.

All patches tested on HP EliteBook 840 G2 (Fedora 44, Linux 7.2.7).

Changes in v2:
 - Split hp_get_string_from_buffer() fixes into two logical patches
   (bounds/OOB reads and UTF-8 conversion rewrite), as reviewed by
   Ilpo Järvinen.
 - Dropped lib/string_helpers patch: pass "\\\r\n\t" to string_escape_mem()
   with existing flags (ESCAPE_SPACE | ESCAPE_SPECIAL) to escape the four
   characters without altering quotes, as reviewed by Andy Shevchenko.
 - Added password validation errno fix as patch 3/3.

Muhammad Bilal (3):
  platform/x86: hp-bioscfg: fix OOB reads in hp_get_string_from_buffer()
  platform/x86: hp-bioscfg: fix non-ASCII truncation in
    hp_get_string_from_buffer()
  platform/x86: hp-bioscfg: return -ERANGE from
    validate_password_input()

 drivers/platform/x86/hp/hp-bioscfg/bioscfg.c  | 77 ++++++-------------
 .../x86/hp/hp-bioscfg/passwdobj-attributes.c  |  6 +-
 2 files changed, 27 insertions(+), 56 deletions(-)

-- 
2.55.0