KEYS: Reinstate EPERM for a key type name beginning with a '.'

Reinstate the generation of EPERM for a key type name beginning with a '.' in
a userspace call.  Types whose name begins with a '.' are internal only.

The test was removed by:

	commit a4e3b8d79a5c6d40f4a9703abf7fe3abcc6c3b8d
	Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
	Date:   Thu May 22 14:02:23 2014 -0400
	Subject: KEYS: special dot prefixed keyring name bug fix

I think we want to keep the restriction on type name so that userspace can't
add keys of a special internal type.

Note that removal of the test causes several of the tests in the keyutils
testsuite to fail.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
cc: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index e26f860e5f2e..eff88a5f5d40 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -37,6 +37,8 @@ static int key_get_type_from_user(char *type,
                 return ret;
         if (ret == 0 || ret >= len)
                 return -EINVAL;
+        if (type[0] == '.')
+                return -EPERM;
         type[len - 1] = '\0';
         return 0;
 }