This patch adds new permission checks to the SELinux mmap and mprotect hooks
to enable control over the ability to make executable a mapping that can
contain data not covered by the existing file-based permission checks.

The task->self execmem permission controls the ability to create an executable
anonymous mapping or a writable executable private file mapping.  The
task->file execmod permission controls the ability to make executable a
previously written private file mapping, e.g.  for text relocations.  Thanks
to Roland McGrath for input and feedback on earlier versions of this patch.
Signed-off-by: Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: James Morris <jmorris@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>