libceph: store session key in cephx authorizer

Session key is required when calculating message signature. Save the session
key in authorizer, this avoid lookup ticket handler for each message

Signed-off-by: Yan, Zheng <[e-mail]>

net/ceph/auth_x.c

···
 	dout("build_authorizer for %s %p\n",
 	     ceph_entity_type_name(th->service), au);
 
+	ceph_crypto_key_destroy(&au->session_key);
+	ret = ceph_crypto_key_clone(&au->session_key, &th->session_key);
+	if (ret)
+		return ret;
+
 	maxlen = sizeof(*msg_a) + sizeof(msg_b) +
 		ceph_x_encrypt_buflen(ticket_blob_len);
 	dout("  need len %d\n", maxlen);
···
 	}
 	if (!au->buf) {
 		au->buf = ceph_buffer_new(maxlen, GFP_NOFS);
-		if (!au->buf)
+		if (!au->buf) {
+			ceph_crypto_key_destroy(&au->session_key);
 			return -ENOMEM;
+		}
 	}
 	au->service = th->service;
 	au->secret_id = th->secret_id;
···
 	get_random_bytes(&au->nonce, sizeof(au->nonce));
 	msg_b.struct_v = 1;
 	msg_b.nonce = cpu_to_le64(au->nonce);
-	ret = ceph_x_encrypt(&th->session_key, &msg_b, sizeof(msg_b),
+	ret = ceph_x_encrypt(&au->session_key, &msg_b, sizeof(msg_b),
 			     p, end - p);
 	if (ret < 0)
 		goto out_buf;
···
 					  struct ceph_authorizer *a, size_t len)
 {
 	struct ceph_x_authorizer *au = (void *)a;
-	struct ceph_x_ticket_handler *th;
 	int ret = 0;
 	struct ceph_x_authorize_reply reply;
 	void *preply = &reply;
 	void *p = au->reply_buf;
 	void *end = p + sizeof(au->reply_buf);
 
-	th = get_ticket_handler(ac, au->service);
-	if (IS_ERR(th))
-		return PTR_ERR(th);
-	ret = ceph_x_decrypt(&th->session_key, &p, end, &preply, sizeof(reply));
+	ret = ceph_x_decrypt(&au->session_key, &p, end, &preply, sizeof(reply));
 	if (ret < 0)
 		return ret;
 	if (ret != sizeof(reply))
···
 {
 	struct ceph_x_authorizer *au = (void *)a;
 
+	ceph_crypto_key_destroy(&au->session_key);
 	ceph_buffer_put(au->buf);
 	kfree(au);
 }

net/ceph/auth_x.h

···
 
 
 struct ceph_x_authorizer {
+	struct ceph_crypto_key session_key;
 	struct ceph_buffer *buf;
 	unsigned int service;
 	u64 nonce;