2023-07-19 09:07:14

by Christian Göttsche

[permalink] [raw]
Subject: Re: [PATCH v2 3/4] selinux: use vma_is_initial_stack() and vma_is_initial_heap()

On Wed, 19 Jul 2023 at 09:40, Kefeng Wang <[email protected]> wrote:
>
> Use the helpers to simplify code.
>
> Cc: Paul Moore <[email protected]>
> Cc: Stephen Smalley <[email protected]>
> Cc: Eric Paris <[email protected]>
> Acked-by: Paul Moore <[email protected]>
> Signed-off-by: Kefeng Wang <[email protected]>
> ---
> security/selinux/hooks.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index d06e350fedee..ee8575540a8e 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -3762,13 +3762,10 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
> if (default_noexec &&
> (prot & PROT_EXEC) && !(vma->vm_flags & VM_EXEC)) {
> int rc = 0;
> - if (vma->vm_start >= vma->vm_mm->start_brk &&
> - vma->vm_end <= vma->vm_mm->brk) {
> + if (vma_is_initial_heap(vma)) {

This seems to change the condition from

vma->vm_start >= vma->vm_mm->start_brk && vma->vm_end <= vma->vm_mm->brk

to

vma->vm_start <= vma->vm_mm->brk && vma->vm_end >= vma->vm_mm->start_brk

(or AND arguments swapped)

vma->vm_end >= vma->vm_mm->start_brk && vma->vm_start <= vma->vm_mm->brk

Is this intended?

> rc = avc_has_perm(sid, sid, SECCLASS_PROCESS,
> PROCESS__EXECHEAP, NULL);
> - } else if (!vma->vm_file &&
> - ((vma->vm_start <= vma->vm_mm->start_stack &&
> - vma->vm_end >= vma->vm_mm->start_stack) ||
> + } else if (!vma->vm_file && (vma_is_initial_stack(vma) ||
> vma_is_stack_for_current(vma))) {
> rc = avc_has_perm(sid, sid, SECCLASS_PROCESS,
> PROCESS__EXECSTACK, NULL);
> --
> 2.27.0
>