selinux: apply execstack check on thread stacks

The execstack check was only being applied on the main
process stack.  Thread stacks allocated via mmap were
only subject to the execmem permission check.  Augment
the check to apply to the current thread stack as well.
Note that this does NOT prevent making a different thread's
stack executable.

Suggested-by: Nick Kralevich <nnk@google.com>
Acked-by: Nick Kralevich <nnk@google.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Stephen Smalley 2016-04-08 13:55:03 -04:00 committed by Paul Moore
parent 8e4ff6f228
commit c2316dbf12

View file

@ -3479,8 +3479,9 @@ static int selinux_file_mprotect(struct vm_area_struct *vma,
vma->vm_end <= vma->vm_mm->brk) {
rc = cred_has_perm(cred, cred, PROCESS__EXECHEAP);
} else if (!vma->vm_file &&
vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack) {
((vma->vm_start <= vma->vm_mm->start_stack &&
vma->vm_end >= vma->vm_mm->start_stack) ||
vma_is_stack_for_task(vma, current))) {
rc = current_has_perm(current, PROCESS__EXECSTACK);
} else if (vma->vm_file && vma->anon_vma) {
/*