selinux: ignore unknown extended permissions

commit 900f83cf376bdaf798b6f5dcb2eae0c822e908b6 upstream.

When evaluating extended permissions, ignore unknown permissions instead
of calling BUG(). This commit ensures that future permissions can be
added without interfering with older kernels.

Cc: stable@vger.kernel.org
Fixes: fa1aa143ac4a ("selinux: extended permissions for ioctls")
Signed-off-by: Thiébaud Weksteen <tweek@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 2b8ebd390e3755a5b3c662fb2660c5e16b3614b5..25599cd5d6ae82194993dba802cca4fd376dbe60 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -969,7 +969,10 @@ void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
                                        xpermd->driver))
                        return;
        } else {
-               BUG();
+               pr_warn_once(
+                       "SELinux: unknown extended permission (%u) will be ignored\n",
+                       node->datum.u.xperms->specified);
+               return;
        }
 
        if (node->key.specified == AVTAB_XPERMS_ALLOWED) {
@@ -1006,7 +1009,8 @@ void services_compute_xperms_decision(struct extended_perms_decision *xpermd,
                                        node->datum.u.xperms->perms.p[i];
                }
        } else {
-               BUG();
+               pr_warn_once("SELinux: unknown specified key (%u)\n",
+                            node->key.specified);
        }
 }