[CRIU] [PATCH 1/2] p.haul: do not use getsockname() as a hash_name, v2

[Pavel Emelyanov]

On 10/23/2014 10:57 PM, Ruslan Kuprieiev wrote:
> Currently xem_rpc is not proxy-resistant.
> It means that if there is a proxy somewhere in
> between client and server, p.haul will fail,
> because getsockname() on client != getpeername()
> on server.
> 
> v2, Pavel suggested to solve it like this:
> 
> 1. On main rpc socket after init_rpc() the server
>    reports back the name by which it sees the client
>    socket.
> 
> 2. After calling connect() on data socket the client
>    should mix the name from step 1 to the data socket
>    name to distinguish his data socket from those
>    created by other clients.
> 
> Signed-off-by: Ruslan Kuprieiev <kupruser at gmail.com>
> ---
>  xem_rpc.py | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/xem_rpc.py b/xem_rpc.py
> index 9718eef..f4a9b21 100644
> --- a/xem_rpc.py
> +++ b/xem_rpc.py
> @@ -3,6 +3,7 @@ import select
>  import threading
>  import traceback
>  import util
> +import struct
>  
>  rpc_port = 12345
>  rpc_sk_buf = 256
> @@ -41,7 +42,7 @@ class _rpc_proxy_caller:
>  class rpc_proxy:
>  	def __init__(self, conn, *args):
>  		self._srv = conn
> -		self._rpc_sk = self._make_sk()
> +		self._rpc_sk = self._make_sk()[0]
>  		util.set_cloexec(self._rpc_sk)
>  		_rpc_proxy_caller(self._rpc_sk, RPC_CMD, "init_rpc")(args)
>  
> @@ -51,12 +52,13 @@ class rpc_proxy:
>  	def _make_sk(self):
>  		sk = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>  		sk.connect((self._srv, rpc_port))
> -		return sk
> +		host = eval(sk.recv(rpc_sk_buf))
> +		return (sk, host)
>  
>  	def open_socket(self, uname):
> -		sk = self._make_sk()
> +		sk, host = self._make_sk()
>  		c = _rpc_proxy_caller(self._rpc_sk, RPC_CMD, "pick_channel")
> -		c(sk.getsockname(), uname)
> +		c(host, uname)
>  		return sk
>  
>  
> @@ -128,6 +130,7 @@ class _rpc_server_ask:
>  
>  	def work(self, mgr):
>  		sk, addr = self._sk.accept()
> +		sk.send(repr(addr))

Don't add new send/recv please. Make use of existing _rpc_proxy_caller,
e.g. look at how the rpc control socket announces itself to the service.

>  		mgr.add(_rpc_server_sk(sk))
>  
>  class _rpc_stop_fd:
>