ceph: ensure RNG is seeded before using

Ceph uses the RNG for various nonce generations, and it shouldn't accept
using bad randomness. So, we wait for the RNG to be properly seeded. We
do this by calling wait_for_random_bytes() in a function that is
certainly called in process context, early on, so that all subsequent
calls to get_random_bytes are necessarily acceptable.

Signed-off-by: Jason A. Donenfeld <[email protected]>
Cc: Ilya Dryomov <[email protected]>
Cc: "Yan, Zheng" <[email protected]>
Cc: Sage Weil <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>

Author: zx2c4

net/ceph/ceph_common.c

@@ -611,7 +611,11 @@ struct ceph_client *ceph_create_client(struct ceph_options *opt, void *private)
 {
 	struct ceph_client *client;
 	struct ceph_entity_addr *myaddr = NULL;
-	int err = -ENOMEM;
+	int err;
+
+	err = wait_for_random_bytes();
+	if (err < 0)
+		return ERR_PTR(err);
 
 	client = kzalloc(sizeof(*client), GFP_KERNEL);
 	if (client == NULL)