linux-kernel - [PATCH 0/2] mm: update mips to use do_mmap(), make mmap

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <cover.1735819274.git.lorenzo.stoakes@oracle.com>
Date: Thu,  2 Jan 2025 12:10:50 +0000
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
        "Liam R . Howlett" <Liam.Howlett@...cle.com>
Cc: Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Vlastimil Babka <vbabka@...e.cz>, Jann Horn <jannh@...gle.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-mips@...r.kernel.org
Subject: [PATCH 0/2] mm: update mips to use do_mmap(), make mmap_region() internal

Currently the only user of mmap_region() outside of the memory management
code is the MIPS VDSO implementation.

This uses mmap_region() to map a 'delay slot emulation page' at the top of
the stack which is read-only and executable.

This mapping requires that an already-acquired mmap write lock is utilised
and that uffd and populate logic is ignored. This rules out vm_mmap(),
however do_mmap() fits the bill.

Adapt this code to use do_mmap() and then once done, make mmap_region()
internal and userland testable, and avoid any other uses of mmap_region(),
which is absolutely and strictly an internal mm function which bypasses a
great number of checks and logic.

v1:
* Stripped RFC, as Thomas indicated that the approach seemed correct from MIPS
  side.
* Avoided whitespace error as pointed out by Matthew.
* Rebased on tip mm-unstable, as previously a conflict emerged after I submitted
  the patch (quite possibly one I caused :P).

RFC:
https://lore.kernel.org/all/cover.1734017293.git.lorenzo.stoakes@oracle.com/

Lorenzo Stoakes (2):
  mips: vdso: prefer do_mmap() to mmap_region()
  mm: make mmap_region() internal

 arch/mips/kernel/vdso.c          | 10 +++--
 include/linux/mm.h               |  3 --
 mm/mmap.c                        | 59 -----------------------------
 mm/vma.c                         | 61 +++++++++++++++++++++++++++++-
 mm/vma.h                         |  2 +-
 tools/testing/vma/vma_internal.h | 65 ++++++++++++++++++++++++++++++++
 6 files changed, 132 insertions(+), 68 deletions(-)

--
2.47.1