KEYS: Propagate error code instead of returning -EINVAL

This is from a Smatch check I'm writing.

strncpy_from_user() returns -EFAULT on error so the first change just
silences a warning but doesn't change how the code works.

The other change is a bug fix because install_thread_keyring_to_cred()
can return a variety of errors such as -EINVAL, -EEXIST, -ENOMEM or
-EKEYREVOKED.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

security/keys/keyctl.c

@@ -33,7 +33,7 @@ static int key_get_type_from_user(char *type,
 	ret = strncpy_from_user(type, _type, len);
 
 	if (ret < 0)
-		return -EFAULT;
+		return ret;
 
 	if (ret == 0 || ret >= len)
 		return -EINVAL;
@@ -1080,7 +1080,7 @@ set:
 	return old_setting;
 error:
 	abort_creds(new);
-	return -EINVAL;
+	return ret;
 
 } /* end keyctl_set_reqkey_keyring() */