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mm/mprotect: replace can_modify_mm with can_modify_vma

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Avoid taking an extra trip down the mmap tree by checking the vmas
directly.  mprotect (per POSIX) tolerates partial failure.

Link: https://lkml.kernel.org/r/20240817-mseal-depessimize-v3-3-d8d2e037df30@gmail.com
Signed-off-by: Pedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Pedro Falcato 2024-08-17 01:18:30 +01:00 committed by Andrew Morton
parent df2a7df9a9
commit 4a2dd02b09
1 changed files with 3 additions and 9 deletions
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12
mm/mprotect.c
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@ -611,6 +611,9 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb,
unsigned long charged = 0; unsigned long charged = 0;
int error; int error;
if (!can_modify_vma(vma))
return -EPERM;
if (newflags == oldflags) { if (newflags == oldflags) {
*pprev = vma; *pprev = vma;
return 0; return 0;
@ -769,15 +772,6 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
} }
} }
/*
* checking if memory is sealed.
* can_modify_mm assumes we have acquired the lock on MM.
*/
if (unlikely(!can_modify_mm(current->mm, start, end))) {
error = -EPERM;
goto out;
}
prev = vma_prev(&vmi); prev = vma_prev(&vmi);
if (start > vma->vm_start) if (start > vma->vm_start)
prev = vma; prev = vma;