KEYS: Add a new keyctl op to reject a key with a specified error code
Add a new keyctl op to reject a key with a specified error code. This works
much the same as negating a key, and so keyctl_negate_key() is made a special
case of keyctl_reject_key(). The difference is that keyctl_negate_key()
selects ENOKEY as the error to be reported.
Typically the key would be rejected with EKEYEXPIRED, EKEYREVOKED or
EKEYREJECTED, but this is not mandatory.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/keys/compat.c b/security/keys/compat.c
index 07a5f35..17c99d0 100644
--- a/security/keys/compat.c
+++ b/security/keys/compat.c
@@ -85,6 +85,9 @@
case KEYCTL_SESSION_TO_PARENT:
return keyctl_session_to_parent();
+ case KEYCTL_REJECT:
+ return keyctl_reject_key(arg2, arg3, arg4, arg5);
+
default:
return -EOPNOTSUPP;
}
diff --git a/security/keys/internal.h b/security/keys/internal.h
index a52aa7c..286c095 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -214,6 +214,7 @@
extern long keyctl_get_security(key_serial_t keyid, char __user *buffer,
size_t buflen);
extern long keyctl_session_to_parent(void);
+extern long keyctl_reject_key(key_serial_t, unsigned, unsigned, key_serial_t);
/*
* Debugging key validation
diff --git a/security/keys/key.c b/security/keys/key.c
index 8e315ef..f7f9d93 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -511,26 +511,29 @@
EXPORT_SYMBOL(key_instantiate_and_link);
/**
- * key_negate_and_link - Negatively instantiate a key and link it into the keyring.
+ * key_reject_and_link - Negatively instantiate a key and link it into the keyring.
* @key: The key to instantiate.
* @timeout: The timeout on the negative key.
+ * @error: The error to return when the key is hit.
* @keyring: Keyring to create a link in on success (or NULL).
* @authkey: The authorisation token permitting instantiation.
*
* Negatively instantiate a key that's in the uninstantiated state and, if
- * successful, set its timeout and link it in to the destination keyring if one
- * is supplied. The key and any links to the key will be automatically garbage
- * collected after the timeout expires.
+ * successful, set its timeout and stored error and link it in to the
+ * destination keyring if one is supplied. The key and any links to the key
+ * will be automatically garbage collected after the timeout expires.
*
* Negative keys are used to rate limit repeated request_key() calls by causing
- * them to return -ENOKEY until the negative key expires.
+ * them to return the stored error code (typically ENOKEY) until the negative
+ * key expires.
*
* If successful, 0 is returned, the authorisation token is revoked and anyone
* waiting for the key is woken up. If the key was already instantiated,
* -EBUSY will be returned.
*/
-int key_negate_and_link(struct key *key,
+int key_reject_and_link(struct key *key,
unsigned timeout,
+ unsigned error,
struct key *keyring,
struct key *authkey)
{
@@ -556,6 +559,7 @@
atomic_inc(&key->user->nikeys);
set_bit(KEY_FLAG_NEGATIVE, &key->flags);
set_bit(KEY_FLAG_INSTANTIATED, &key->flags);
+ key->type_data.reject_error = -error;
now = current_kernel_time();
key->expiry = now.tv_sec + timeout;
key_schedule_gc(key->expiry + key_gc_delay);
@@ -585,8 +589,7 @@
return ret == 0 ? link_ret : ret;
}
-
-EXPORT_SYMBOL(key_negate_and_link);
+EXPORT_SYMBOL(key_reject_and_link);
/*
* Garbage collect keys in process context so that we don't have to disable
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 31a0fd8..0d7b194 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -1013,12 +1013,42 @@
*/
long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
{
+ return keyctl_reject_key(id, timeout, ENOKEY, ringid);
+}
+
+/*
+ * Negatively instantiate the key with the given timeout (in seconds) and error
+ * code and link the key into the destination keyring if one is given.
+ *
+ * The caller must have the appropriate instantiation permit set for this to
+ * work (see keyctl_assume_authority). No other permissions are required.
+ *
+ * The key and any links to the key will be automatically garbage collected
+ * after the timeout expires.
+ *
+ * Negative keys are used to rate limit repeated request_key() calls by causing
+ * them to return the specified error code until the negative key expires.
+ *
+ * If successful, 0 will be returned.
+ */
+long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
+ key_serial_t ringid)
+{
const struct cred *cred = current_cred();
struct request_key_auth *rka;
struct key *instkey, *dest_keyring;
long ret;
- kenter("%d,%u,%d", id, timeout, ringid);
+ kenter("%d,%u,%u,%d", id, timeout, error, ringid);
+
+ /* must be a valid error code and mustn't be a kernel special */
+ if (error <= 0 ||
+ error >= MAX_ERRNO ||
+ error == ERESTARTSYS ||
+ error == ERESTARTNOINTR ||
+ error == ERESTARTNOHAND ||
+ error == ERESTART_RESTARTBLOCK)
+ return -EINVAL;
/* the appropriate instantiation authorisation key must have been
* assumed before calling this */
@@ -1038,7 +1068,7 @@
goto error;
/* instantiate the key and link it into a keyring */
- ret = key_negate_and_link(rka->target_key, timeout,
+ ret = key_reject_and_link(rka->target_key, timeout, error,
dest_keyring, instkey);
key_put(dest_keyring);
@@ -1492,6 +1522,12 @@
case KEYCTL_SESSION_TO_PARENT:
return keyctl_session_to_parent();
+ case KEYCTL_REJECT:
+ return keyctl_reject_key((key_serial_t) arg2,
+ (unsigned) arg3,
+ (unsigned) arg4,
+ (key_serial_t) arg5);
+
default:
return -EOPNOTSUPP;
}
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 5620f08..cdd2f3f 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -352,7 +352,7 @@
goto error_2;
if (key->expiry && now.tv_sec >= key->expiry)
goto error_2;
- key_ref = ERR_PTR(-ENOKEY);
+ key_ref = ERR_PTR(key->type_data.reject_error);
if (kflags & (1 << KEY_FLAG_NEGATIVE))
goto error_2;
goto found;
@@ -401,7 +401,7 @@
/* we set a different error code if we pass a negative key */
if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
- err = -ENOKEY;
+ err = key->type_data.reject_error;
continue;
}
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index a3dc0d4..df3c041 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -585,7 +585,7 @@
if (ret < 0)
return ret;
if (test_bit(KEY_FLAG_NEGATIVE, &key->flags))
- return -ENOKEY;
+ return key->type_data.reject_error;
return key_validate(key);
}
EXPORT_SYMBOL(wait_for_key_construction);