SELinux: create new open permission

Adds a new open permission inside SELinux when 'opening' a file.  The idea
is that opening a file and reading/writing to that file are not the same
thing.  Its different if a program had its stdout redirected to /tmp/output
than if the program tried to directly open /tmp/output. This should allow
policy writers to more liberally give read/write permissions across the
policy while still blocking many design and programing flaws SELinux is so
good at catching today.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/selinux/ss/services.c

@@ -61,6 +61,7 @@ extern void selnl_notify_policyload(u32 seqno);
 unsigned int policydb_loaded_version;
 
 int selinux_policycap_netpeer;
+int selinux_policycap_openperm;
 
 /*
  * This is declared in avc.c
@@ -1308,6 +1309,8 @@ static void security_load_policycaps(void)
 {
 	selinux_policycap_netpeer = ebitmap_get_bit(&policydb.policycaps,
 						  POLICYDB_CAPABILITY_NETPEER);
+	selinux_policycap_openperm = ebitmap_get_bit(&policydb.policycaps,
+						  POLICYDB_CAPABILITY_OPENPERM);
 }
 
 extern void selinux_complete_init(void);