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Message-ID: <20170607123505.16629-1-igor.stoppa@huawei.com>
Date: Wed, 7 Jun 2017 15:35:01 +0300
From: Igor Stoppa <igor.stoppa@...wei.com>
To: <keescook@...omium.org>, <mhocko@...nel.org>, <jmorris@...ei.org>
CC: <penguin-kernel@...ove.SAKURA.ne.jp>, <paul@...l-moore.com>,
<sds@...ho.nsa.gov>, <casey@...aufler-ca.com>, <hch@...radead.org>,
<labbott@...hat.com>, <linux-security-module@...r.kernel.org>,
<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
<kernel-hardening@...ts.openwall.com>,
Igor Stoppa <igor.stoppa@...wei.com>
Subject: [PATCH v6 0/4] ro protection for dynamic data
Hi,
please consider for inclusion.
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).
Changes since the v5 version:
- use unsigned long for __PMALLOC_ALIGNED alignment
- fixed a regression where size in bytes was used instead of size in words
- tightened the update of the pools list during removal, by doing
earlier the decrement of the atomic counter
The only question still open is if there should be a possibility for
unprotecting a memory pool in other cases than destruction.
The only cases found for this topic are:
- protecting the LSM header structure between creation and insertion of a
security module that was not built as part of the kernel
(but the module can protect the headers after it has loaded)
- unloading SELinux from RedHat, if the system has booted, but no policy
has been loaded yet - this feature is going away, according to Casey.
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
list_head
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 | 339 +++++++++++++++++++++++++++++++++
mm/usercopy.c | 24 ++-
security/security.c | 49 +++--
10 files changed, 631 insertions(+), 230 deletions(-)
create mode 100644 include/linux/pmalloc.h
create mode 100644 mm/pmalloc.c
--
2.9.3
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