Commit 4a2dd02b authored by Pedro Falcato's avatar Pedro Falcato Committed by Andrew Morton
Browse files

mm/mprotect: replace can_modify_mm with can_modify_vma 

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: default avatarPedro Falcato <pedro.falcato@gmail.com>
Reviewed-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: default avatarLorenzo 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent df2a7df9

mm/mprotect.c

+3 −9
Original line number Diff line number Diff line
@@ -611,6 +611,9 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, 
	unsigned long charged = 0;

	int error;



	if (!can_modify_vma(vma))

		return -EPERM;



	if (newflags == oldflags) {

		*pprev = vma;

		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);

	if (start > vma->vm_start)

		prev = vma;