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 92d4f93c59c7f4c462314f04564022d0b5f7d4c3..464d2c71453157ed3eada7d926b1bc4fa5cd60c0 100644 (file)
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -971,7 +971,10 @@ 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) {
@@ -1008,7 +1011,8 @@ 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);
        }
 }