Merge branch 'bug-fixes-for-net-handshake'

Chuck Lever says:

====================
Bug fixes for net/handshake

Paolo observed that there is a possible leak of sock->file. I
haven't looked into that yet, but it seems to be separate from
the fixes in this series, so no need to hold these up.
====================

The submissions mentions net-next but it means netdev (perhaps
merge window left over when trees are converged). In any case,
it should have gone into net, but was instead applied to net-next
as commit deb2e48 ("Merge branch 'net-handshake-fixes'").
These are fixes tho, and Chuck needs them to make progress with
the client so double-merging them into net... it is what it is :(

Link: https://lore.kernel.org/r/168381978252.84244.1933636428135211300.stgit@91.116.238.104.host.secureserver.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

Documentation/netlink/specs/handshake.yaml

@@ -68,6 +68,9 @@ attribute-sets:
         type: nest
         nested-attributes: x509
         multi-attr: true
+      -
+        name: peername
+        type: string
   -
     name: done
     attributes:
@@ -105,6 +108,7 @@ operations:
             - auth-mode
             - peer-identity
             - certificate
+            - peername
     -
       name: done
       doc: Handler reports handshake completion

Documentation/networking/tls-handshake.rst

@@ -53,6 +53,7 @@ fills in a structure that contains the parameters of the request:
         struct socket   *ta_sock;
         tls_done_func_t ta_done;
         void            *ta_data;
+        const char      *ta_peername;
         unsigned int    ta_timeout_ms;
         key_serial_t    ta_keyring;
         key_serial_t    ta_my_cert;
@@ -71,6 +72,10 @@ instantiated a struct file in sock->file.
 has completed. Further explanation of this function is in the "Handshake
 Completion" sesction below.
 
+The consumer can provide a NUL-terminated hostname in the @ta_peername
+field that is sent as part of ClientHello. If no peername is provided,
+the DNS hostname associated with the server's IP address is used instead.
+
 The consumer can fill in the @ta_timeout_ms field to force the servicing
 handshake agent to exit after a number of milliseconds. This enables the
 socket to be fully closed once both the kernel and the handshake agent

include/net/handshake.h

@@ -24,6 +24,7 @@ struct tls_handshake_args {
 	struct socket		*ta_sock;
 	tls_done_func_t		ta_done;
 	void			*ta_data;
+	const char		*ta_peername;
 	unsigned int		ta_timeout_ms;
 	key_serial_t		ta_keyring;
 	key_serial_t		ta_my_cert;

include/uapi/linux/handshake.h

@@ -44,6 +44,7 @@ enum {
 	HANDSHAKE_A_ACCEPT_AUTH_MODE,
 	HANDSHAKE_A_ACCEPT_PEER_IDENTITY,
 	HANDSHAKE_A_ACCEPT_CERTIFICATE,
+	HANDSHAKE_A_ACCEPT_PEERNAME,
 
 	__HANDSHAKE_A_ACCEPT_MAX,
 	HANDSHAKE_A_ACCEPT_MAX = (__HANDSHAKE_A_ACCEPT_MAX - 1)

net/handshake/handshake.h

@@ -31,6 +31,7 @@ struct handshake_req {
 	struct list_head		hr_list;
 	struct rhash_head		hr_rhash;
 	unsigned long			hr_flags;
+	struct file			*hr_file;
 	const struct handshake_proto	*hr_proto;
 	struct sock			*hr_sk;
 	void				(*hr_odestruct)(struct sock *sk);

net/handshake/netlink.c

@@ -48,7 +48,7 @@ int handshake_genl_notify(struct net *net, const struct handshake_proto *proto,
 				proto->hp_handler_class))
 		return -ESRCH;
 
-	msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	msg = genlmsg_new(GENLMSG_DEFAULT_SIZE, flags);
 	if (!msg)
 		return -ENOMEM;
 
@@ -99,9 +99,6 @@ static int handshake_dup(struct socket *sock)
 	struct file *file;
 	int newfd;
 
-	if (!sock->file)
-		return -EBADF;
-
 	file = get_file(sock->file);
 	newfd = get_unused_fd_flags(O_CLOEXEC);
 	if (newfd < 0) {
@@ -142,15 +139,16 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 		goto out_complete;
 	}
 	err = req->hr_proto->hp_accept(req, info, fd);
-	if (err)
+	if (err) {
+		fput(sock->file);
 		goto out_complete;
+	}
 
 	trace_handshake_cmd_accept(net, req, req->hr_sk, fd);
 	return 0;
 
 out_complete:
 	handshake_complete(req, -EIO, NULL);
-	fput(sock->file);
 out_status:
 	trace_handshake_cmd_accept_err(net, req, NULL, err);
 	return err;
@@ -159,8 +157,8 @@ int handshake_nl_accept_doit(struct sk_buff *skb, struct genl_info *info)
 int handshake_nl_done_doit(struct sk_buff *skb, struct genl_info *info)
 {
 	struct net *net = sock_net(skb->sk);
+	struct handshake_req *req = NULL;
 	struct socket *sock = NULL;
-	struct handshake_req *req;
 	int fd, status, err;
 
 	if (GENL_REQ_ATTR_CHECK(info, HANDSHAKE_A_DONE_SOCKFD))

net/handshake/request.c

@@ -239,6 +239,7 @@ int handshake_req_submit(struct socket *sock, struct handshake_req *req,
 	}
 	req->hr_odestruct = req->hr_sk->sk_destruct;
 	req->hr_sk->sk_destruct = handshake_sk_destruct;
+	req->hr_file = sock->file;
 
 	ret = -EOPNOTSUPP;
 	net = sock_net(req->hr_sk);
@@ -334,6 +335,9 @@ bool handshake_req_cancel(struct sock *sk)
 		return false;
 	}
 
+	/* Request accepted and waiting for DONE */
+	fput(req->hr_file);
+
 out_true:
 	trace_handshake_cancel(net, req, sk);
 

net/handshake/tlshd.c

@@ -31,6 +31,7 @@ struct tls_handshake_req {
 	int			th_type;
 	unsigned int		th_timeout_ms;
 	int			th_auth_mode;
+	const char		*th_peername;
 	key_serial_t		th_keyring;
 	key_serial_t		th_certificate;
 	key_serial_t		th_privkey;
@@ -48,6 +49,7 @@ tls_handshake_req_init(struct handshake_req *req,
 	treq->th_timeout_ms = args->ta_timeout_ms;
 	treq->th_consumer_done = args->ta_done;
 	treq->th_consumer_data = args->ta_data;
+	treq->th_peername = args->ta_peername;
 	treq->th_keyring = args->ta_keyring;
 	treq->th_num_peerids = 0;
 	treq->th_certificate = TLS_NO_CERT;
@@ -214,6 +216,12 @@ static int tls_handshake_accept(struct handshake_req *req,
 	ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_MESSAGE_TYPE, treq->th_type);
 	if (ret < 0)
 		goto out_cancel;
+	if (treq->th_peername) {
+		ret = nla_put_string(msg, HANDSHAKE_A_ACCEPT_PEERNAME,
+				     treq->th_peername);
+		if (ret < 0)
+			goto out_cancel;
+	}
 	if (treq->th_timeout_ms) {
 		ret = nla_put_u32(msg, HANDSHAKE_A_ACCEPT_TIMEOUT, treq->th_timeout_ms);
 		if (ret < 0)