From: sashiko-bot@kernel.org
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: kvmarm@lists.linux.dev,
"Alexander Gordeev" <agordeev@linux.ibm.com>,
dri-devel@lists.freedesktop.org,
"Christian Borntraeger" <borntraeger@linux.ibm.com>,
"Marc Zyngier" <maz@kernel.org>,
linux-perf-users@vger.kernel.org, linux-s390@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-scsi@vger.kernel.org, kvm@vger.kernel.org,
"Heiko Carstens" <hca@linux.ibm.com>,
selinux@vger.kernel.org, "Vasily Gorbik" <gor@linux.ibm.com>,
bpf@vger.kernel.org, "Oliver Upton" <oupton@kernel.org>
Subject: Re: [PATCH v2 12/40] selinux: reject writable opens of policy file, drop mmap shared/write check
Date: Mon, 14 Sep 2026 17:57:09 +0000 [thread overview]
Message-ID: <20260914175710.39AD51F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20260914-b4-mmap-prepare-vma-flag-sanify-v2-12-7d9781ed5361@kernel.org>
> The policy file has no write method and is exposed read-only (S_IRUGO in
> selinux_files[]), yet sel_open_policy() performs no open mode check, so a
> CAP_DAC_OVERRIDE caller can open it O_RDWR. Reject FMODE_WRITE at open, as
> kernfs does.
>
> The file can then never be mapped with FMODE_WRITE, so do_mmap() always
> clears VM_MAYWRITE and VM_SHARED for MAP_SHARED mappings and the VM_SHARED
> check in sel_mmap_policy() cannot be reached. Remove it.
>
> This also stops sel_mmap_policy() clearing VM_MAYWRITE on a mapping that is
> neither a PFN map nor a mixed map, ahead of the core enforcing that only
> such mappings may do so.
>
> Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
> Reviewed-by: Jann Horn <jannh@google.com>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260914-b4-mmap-prepare-vma-flag-sanify-v2-0-7d9781ed5361@kernel.org?part=12
next prev parent reply other threads:[~2026-09-14 17:57 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 14:57 [PATCH v2 00/40] mm: make VMA flag semantics explicit, eliminate VM_SPECIAL Lorenzo Stoakes (ARM)
2026-09-14 14:57 ` [PATCH v2 01/40] mm/vma: fix mmap_prepare file handling, remove file_doesnt_need_get Lorenzo Stoakes (ARM)
2026-09-14 15:40 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 02/40] mm/vma: predicate setting mmap_prepare VMA fields on new vma alloc Lorenzo Stoakes (ARM)
2026-09-14 15:55 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 03/40] mm/vma: introduce and use vma_[flags_]can_merge() Lorenzo Stoakes (ARM)
2026-09-14 15:59 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 04/40] mm: consistently validate VMA state after mmap[_prepare] hooks Lorenzo Stoakes (ARM)
2026-09-14 16:18 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 05/40] mm/vma: ensure mmap_prepare doesn't set actions on a mergeable vma Lorenzo Stoakes (ARM)
2026-09-14 16:45 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 06/40] mm: make map_kernel_pages_[prepare,complete] internal and unexported Lorenzo Stoakes (ARM)
2026-09-14 16:47 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 07/40] mm/vma: tidy up map kernel pages enum values Lorenzo Stoakes (ARM)
2026-09-14 16:50 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 08/40] mm: add mmap action for discontiguous kernel page mapping Lorenzo Stoakes (ARM)
2026-09-14 17:03 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 09/40] docs: filesystems: update mmap_prepare docs for discontig kernel pgs Lorenzo Stoakes (ARM)
2026-09-14 17:07 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 10/40] drivers/usb/mon: update to use mmap_prepare + map kernel pages Lorenzo Stoakes (ARM)
2026-09-14 17:18 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 11/40] infiniband: update hfi1 to use remap_vmalloc_range() Lorenzo Stoakes (ARM)
2026-09-14 17:39 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 12/40] selinux: reject writable opens of policy file, drop mmap shared/write check Lorenzo Stoakes (ARM)
2026-09-14 17:57 ` sashiko-bot [this message]
2026-09-14 19:57 ` Paul Moore
2026-09-14 14:57 ` [PATCH v2 13/40] ALSA: pcm: use vm_insert_page() to map PCM status page Lorenzo Stoakes (ARM)
2026-09-14 18:30 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 14/40] bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-14 18:46 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 15/40] mm/vma: add vma[_flags]_is_kernel_owned() predicates Lorenzo Stoakes (ARM)
2026-09-14 18:50 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 16/40] mm/vma: only allow mmap to clear VMA_MAYWRITE_BIT if kernel-owned Lorenzo Stoakes (ARM)
2026-09-14 19:14 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 17/40] mm/vma: add and use vma_[flags]_is_fixed_mapping Lorenzo Stoakes (ARM)
2026-09-14 19:24 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 18/40] scsi: sg: convert mmap hook to mmap_prepare and rework Lorenzo Stoakes (ARM)
2026-09-14 19:30 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 19/40] fbdev: defio: assert FBINFO_VIRTFB, drop VM_IO, add VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-14 19:44 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 20/40] HSI: cmt_speech: convert mmap hook to mmap_prepare, refactor Lorenzo Stoakes (ARM)
2026-09-14 20:15 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 21/40] mm/gup: error out early on !VMA_MAYREAD_BIT VMAs Lorenzo Stoakes (ARM)
2026-09-14 20:33 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 22/40] uprobes: remove VM_IO, set VM_MIXEDMAP for mapped kernel pages Lorenzo Stoakes (ARM)
2026-09-14 20:47 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 23/40] mm/mlock: clear VMA_LOCKED_MASK over mmap callback Lorenzo Stoakes (ARM)
2026-09-14 21:09 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 24/40] mm/mlock: eliminate weird VMA_IO_BIT abuse and simplify Lorenzo Stoakes (ARM)
2026-09-14 21:44 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 25/40] mm/vma: enforce that only kernel-owned mappings may set VMA_IO_BIT Lorenzo Stoakes (ARM)
2026-09-14 22:18 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 26/40] mm: remove VMA_IO_BIT check in vma[_flags]_is_kernel_owned() Lorenzo Stoakes (ARM)
2026-09-14 22:09 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 27/40] mm: remove hugetlb_inline.h Lorenzo Stoakes (ARM)
2026-09-14 22:09 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 28/40] mm: rename is_vm_hugetlb_page() to vma_is_hugetlb() Lorenzo Stoakes (ARM)
2026-09-14 14:57 ` [PATCH v2 29/40] mm: drop some redundant checks around hugetlb VMAs Lorenzo Stoakes (ARM)
2026-09-14 22:08 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 30/40] mm/madvise: update is_valid_guard_vma() to use vma_can_merge() Lorenzo Stoakes (ARM)
2026-09-14 22:14 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 31/40] mm/vma: introduce vma[_flags]_is_persistent() Lorenzo Stoakes (ARM)
2026-09-14 22:12 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 32/40] mm/uffd: use predicates for userfaultfd checks Lorenzo Stoakes (ARM)
2026-09-14 22:16 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 33/40] mm/madvise: use predicates for madvise(..., MADV_DOFORK) Lorenzo Stoakes (ARM)
2026-09-14 22:18 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 34/40] mm: eliminate VMA_SPECIAL_FLAGS usage when hugetlb explicitly tested Lorenzo Stoakes (ARM)
2026-09-14 22:21 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 35/40] mm: eliminate VMA_SPECIAL_FLAGS check in lru_gen_look_around() Lorenzo Stoakes (ARM)
2026-09-14 22:22 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 36/40] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup() Lorenzo Stoakes (ARM)
2026-09-14 22:23 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 37/40] mm: eliminate VM_SPECIAL, VMA_SPECIAL_FLAGS Lorenzo Stoakes (ARM)
2026-09-14 22:19 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 38/40] fuse: dax: do not set VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-14 22:30 ` sashiko-bot
2026-09-14 14:57 ` [PATCH v2 39/40] mm/huge_memory: remove vma_is_special_huge() Lorenzo Stoakes (ARM)
2026-09-14 22:26 ` sashiko-bot
2026-09-14 14:58 ` [PATCH v2 40/40] mm/vma: introduce and use vma[_flags]_can_gup() Lorenzo Stoakes (ARM)
2026-09-14 22:25 ` sashiko-bot
2026-09-15 1:08 ` [PATCH v2 00/40] mm: make VMA flag semantics explicit, eliminate VM_SPECIAL Andrew Morton
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