[LTP] [PATCH v2 0/3] Separate ptrace tests for CONFIG_PROC_MEM_FORCE_PTRACE

[Jan Polensky]

thp04 is a CVE-2017-1000405 regression test. If direct
/proc/self/mem writes are blocked by CONFIG_PROC_MEM_FORCE_PTRACE=y,
the CVE cannot be triggered and thp04 should report TCONF.

Add separate ptrace tests for the CONFIG_PROC_MEM_FORCE_PTRACE behavior
instead:

- ptrace12 checks that writing to /proc/self/mem is rejected with EIO.
- ptrace13 checks that a parent can write to a traced child's memory via
  /proc/pid/mem.

Both ptrace tests use read-only mappings, so the writes require
FOLL_FORCE and exercise the CONFIG_PROC_MEM_FORCE_PTRACE enforcement.

Validated on s390x with CONFIG_PROC_MEM_FORCE_PTRACE=y:

- ptrace12: TPASS
- ptrace13: TPASS, 100 iterations

Follow-up to the previous thp04 ptrace mode discussion:
https://lore.kernel.org/all/20260709175927.268677-1-japo@linux.ibm.com/

Changes in v2:
- thp04: Removed .forks_child flag (not needed without actual fork)
- thp04: Changed MAP_SHARED to MAP_PRIVATE for child state mapping
- thp04: Added missing #include <string.h> for memset()
- thp04: Renamed struct child_state → struct thp_state (no longer uses fork)
- thp04: Renamed child → state, child_setup() → thp_setup(), child_cleanup() → thp_cleanup()
- ptrace12: Removed deprecated [Description] line from doc block
- ptrace12: Replaced bare write() with TEST() macro, using TST_RET/TST_ERR
- ptrace12: Adjusted setup comment to clarify page initialization sequence
- ptrace13: Removed deprecated [Description] line from doc block
- ptrace13: Added missing #include <string.h> for memset()
- Both ptrace tests: Added to runtest/syscalls

v1: https://lore.kernel.org/all/20260714150631.250972-1-japo@linux.ibm.com/

Jan Polensky (3):
  thp04: Simplify to focus on CVE-2017-1000405 race test only
  ptrace: add test for /proc/self/mem write rejection
  ptrace: add test for /proc/pid/mem writes under ptrace

 runtest/syscalls                            |   2 +
 testcases/kernel/mem/thp/thp04.c            | 166 +++++++++-----
 testcases/kernel/syscalls/ptrace/.gitignore |   2 +
 testcases/kernel/syscalls/ptrace/ptrace12.c |  96 ++++++++
 testcases/kernel/syscalls/ptrace/ptrace13.c | 235 ++++++++++++++++++++
 5 files changed, 449 insertions(+), 52 deletions(-)
 create mode 100644 testcases/kernel/syscalls/ptrace/ptrace12.c
 create mode 100644 testcases/kernel/syscalls/ptrace/ptrace13.c


base-commit: d139524b04d360c4dabaee61a6066a9a52b0e454
prerequisite-patch-id: fb884fb8843ffadb56383142ca39c8f3f2db898d
prerequisite-patch-id: 16fc00d302aefbf6fb17e972a4390341bfbb0e50
prerequisite-patch-id: 6e77ef09b2259daae915f4a4895bf0879b7b7211
prerequisite-patch-id: 1d13f676c1c1b9b37e97b1e18ae75611a3516f96
prerequisite-patch-id: 11b8f2b102029b41838899f2a78132b50cac12a0
prerequisite-patch-id: 811e85d9a4158f72559de5f551ad93f109362c96
--
2.55.0