[PATCH] recognize MAP_LOCKED in mmap() call

[Hubertus Franke]

--------------Boundary-00=_E46NZG7A4M3X1RKLRVT1
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 8bit

Andrew, at the current time an mmap() ignores a MAP_LOCKED passed to it.
The only way we can get VM_LOCKED associated with the newly created VMA
is to have previously called mlockall() on the process which sets the 
mm->def_flags != VM_LOCKED or subsequently call mlock() on the
newly created VMA.

The attached patch checks for MAP_LOCKED being passed and if so checks
the capabilities of the process. Limit checks were already in place.
-- 
-- Hubertus Franke  ([e-mail])

--------------------------------< PATCH >------------------------------
--- linux-2.5.35/mm/mmap.c	Wed Sep 18 11:12:13 2002
+++ linux-2.5.35-fix/mm/mmap.c	Wed Sep 18 11:44:32 2002
@@ -461,6 +461,11 @@
 	 */
 	vm_flags = calc_vm_flags(prot,flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
+	if (flags & MAP_LOCKED) {
+		if (!capable(CAP_IPC_LOCK))
+			return -EPERM;
+		vm_flags |= VM_LOCKED;
+	}
 	/* mlock MCL_FUTURE? */
 	if (vm_flags & VM_LOCKED) {
 		unsigned long locked = mm->locked_vm << PAGE_SHIFT;

--------------Boundary-00=_E46NZG7A4M3X1RKLRVT1
Content-Type: text/x-diff;
  charset="iso-8859-1";
  name="patch.2.5.35.mmap_locked"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="patch.2.5.35.mmap_locked"

--- linux-2.5.35/mm/mmap.c	Wed Sep 18 11:12:13 2002
+++ linux-2.5.35-fix/mm/mmap.c	Wed Sep 18 11:44:32 2002
@@ -461,6 +461,11 @@
 	 */
 	vm_flags = calc_vm_flags(prot,flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
+	if (flags & MAP_LOCKED) {
+		if (!capable(CAP_IPC_LOCK))
+			return -EPERM;
+		vm_flags |= VM_LOCKED;
+	}
 	/* mlock MCL_FUTURE? */
 	if (vm_flags & VM_LOCKED) {
 		unsigned long locked = mm->locked_vm << PAGE_SHIFT;

--------------Boundary-00=_E46NZG7A4M3X1RKLRVT1--