selinux: change handling of invalid classes (Was: Re: 2.6.26-rc5-mm1 selinux whine)

On Mon, 2008-06-09 at 01:24 -0700, Andrew Morton wrote:
> Getting a few of these with FC5:
>
> SELinux: context_struct_compute_av:  unrecognized class 69
> SELinux: context_struct_compute_av:  unrecognized class 69
>
> one came out when I logged in.
>
> No other symptoms, yet.

Change handling of invalid classes by SELinux, reporting class values
unknown to the kernel as errors (w/ ratelimit applied) and handling
class values unknown to policy as normal denials.

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

1 files changed, 13 insertions, 3 deletions

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 543fd0f31b33..04c0b70c8012 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -407,9 +407,19 @@ static int context_struct_compute_av(struct context *scontext,
         return 0;
 
 inval_class:
-        printk(KERN_ERR "SELinux: %s:  unrecognized class %d\n", __func__,
-                tclass);
-        return -EINVAL;
+        if (!tclass || tclass > kdefs->cts_len ||
+            !kdefs->class_to_string[tclass]) {
+                if (printk_ratelimit())
+                        printk(KERN_ERR "SELinux: %s:  unrecognized class %d\n",
+                               __func__, tclass);
+                return -EINVAL;
+        }
+
+        /*
+         * Known to the kernel, but not to the policy.
+         * Handle as a denial (allowed is 0).
+         */
+        return 0;
 }
 
 /*