From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 8 Jul 2010 14:00:26 -0400
Subject: [security] keys: new key flag for add_key from userspace
Message-id: <1278597627-23193-2-git-send-email-jlayton@redhat.com>
Patchwork-id: 26762
O-Subject: [RHEL5.6 PATCH 1/2] BZ#612171: keys: new key flag to indicate an
	add_key from userspace
Bugzilla: 612171
CVE: CVE-2010-2524
RH-Acked-by: Steve Dickson <SteveD@redhat.com>
RH-Acked-by: David Howells <dhowells@redhat.com>

For some keys, we don't really want to allow users to stuff the keyring
with values of their own choosing. Add a new key flag that indicates that
an instantiation request is for an add_key() call from userspace. The
instantiation routine for the key can then reject requests based on this
if it needs to.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

diff --git a/include/linux/key.h b/include/linux/key.h
index 451063a..51c1bcb 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -150,6 +150,7 @@ struct key {
 #define KEY_FLAG_IN_QUOTA	3	/* set if key consumes quota */
 #define KEY_FLAG_USER_CONSTRUCT	4	/* set if key is being constructed in userspace */
 #define KEY_FLAG_NEGATIVE	5	/* set if key is negative */
+#define KEY_FLAG_ADDED		6	/* set if key is being added via userspace add_key */
 
 	/* the description string
 	 * - this is used to match a key against search criteria
diff --git a/security/keys/key.c b/security/keys/key.c
index 98f1f85..52b7b55 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -839,6 +839,9 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 		goto error_3;
 	}
 
+	/* this is an unsolicited add_key() call from userspace */
+	set_bit(KEY_FLAG_ADDED, &key->flags);
+
 	/* instantiate it and link it into the target keyring */
 	ret = __key_instantiate_and_link(key, payload, plen, keyring, NULL);
 	if (ret < 0) {