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Date: Tue, 6 Jun 2017 21:24:49 +0300
From: Igor Stoppa <>
To: <>, <>, <>
CC: <>, <>,
        <>, <>, <>,
        <>, <>,
        <>, <>,
        Igor Stoppa <>
Subject: [RFC v5 PATCH 0/4] NOT FOR MERGE - ro protection for dynamic data 

This patchset introduces the possibility of protecting memory that has
been allocated dynamically.

The memory is managed in pools: when a pool is made R/O, all the memory
that is part of it, will become R/O.

A R/O pool can be destroyed to recover its memory, but it cannot be
turned back into R/W mode.

This is intentional. This feature is meant for data that doesn't need
further modifications, after initialization.

An example is provided, showing how to turn into a boot-time option the
writable state of the security hooks.
Prior to this patch, it was a compile-time option.

This is made possible, thanks to Tetsuo Handa's rework of the hooks
structure (included in the patchset).

Since the previous version, I have applied fixes for all the issues
discovered that had a clear resolution:

- %p -> pK
- make the feature depend on ARCH_HAS_SET_MEMORY
- fix the range of the page scanning for hardened user copy
- fixed pointer checking for NULL dereferencing

And a couple of issues I found myself:
- return NULL in case someone asks memory from a locked pool
- turn the "protected" flag into atomic type

Still open (at least I didn't get the impression there was a closure):
- need for specific __PMALLOC_ALIGNED ?
- is it really needed to unprotect a pool?
  can't it wait for the implementation of write-seldom?

Igor Stoppa (3):
  Protectable Memory Allocator
  Protectable Memory Allocator - Debug interface
  Make LSM Writable Hooks a command line option

Tetsuo Handa (1):
  LSM: Convert security_hook_heads into explicit array of struct

 include/linux/lsm_hooks.h      | 412 ++++++++++++++++++++---------------------
 include/linux/page-flags.h     |   2 +
 include/linux/pmalloc.h        |  20 ++
 include/trace/events/mmflags.h |   1 +
 init/main.c                    |   2 +
 mm/Kconfig                     |  11 ++
 mm/Makefile                    |   1 +
 mm/pmalloc.c                   | 340 ++++++++++++++++++++++++++++++++++
 mm/usercopy.c                  |  24 ++-
 security/security.c            |  49 +++--
 10 files changed, 632 insertions(+), 230 deletions(-)
 create mode 100644 include/linux/pmalloc.h
 create mode 100644 mm/pmalloc.c


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