diff options
| author | Lorenzo Stoakes <lorenzo.stoakes@oracle.com> | 2025-07-25 09:29:42 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-08-02 12:06:09 -0700 |
| commit | d0b47a6866f1047247061f3a38f12a981825b265 (patch) | |
| tree | dd8535557128e0d5c0c11974b159a641d16dc6e5 /mm/vma.h | |
| parent | f225b34f1e6c81c50e48f6207ddb6d290be1b932 (diff) | |
| download | tip-d0b47a6866f1047247061f3a38f12a981825b265.tar.gz | |
mm/mseal: update madvise() logic
The madvise() logic is inexplicably performed in mm/mseal.c - this ought
to be located in mm/madvise.c.
Additionally can_modify_vma_madv() is inconsistently named and, in
combination with is_ro_anon(), is very confusing logic.
Put a static function in mm/madvise.c instead - can_madvise_modify() -
that spells out exactly what's happening. Also explicitly check for an
anon VMA.
Also add commentary to explain what's going on.
Essentially - we disallow discarding of data in mseal()'d mappings in
instances where the user couldn't otherwise write to that data.
We retain the existing behaviour here regarding MAP_PRIVATE mappings of
file-backed mappings, which entails some complexity - while this, strictly
speaking - appears to violate mseal() semantics, it may interact badly
with users which expect to be able to madvise(MADV_DONTNEED) .text
mappings for instance.
We may revisit this at a later date.
No functional change intended.
Link: https://lkml.kernel.org/r/492a98d9189646e92c8f23f4cce41ed323fe01df.1753431105.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/vma.h')
| -rw-r--r-- | mm/vma.h | 7 |
1 files changed, 0 insertions, 7 deletions
diff --git a/mm/vma.h b/mm/vma.h index acdcc515c459d5..85db5e880fccee 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -577,8 +577,6 @@ static inline bool can_modify_vma(struct vm_area_struct *vma) return true; } -bool can_modify_vma_madv(struct vm_area_struct *vma, int behavior); - #else static inline bool can_modify_vma(struct vm_area_struct *vma) @@ -586,11 +584,6 @@ static inline bool can_modify_vma(struct vm_area_struct *vma) return true; } -static inline bool can_modify_vma_madv(struct vm_area_struct *vma, int behavior) -{ - return true; -} - #endif #if defined(CONFIG_STACK_GROWSUP) |