[New-bugs-announce] [issue5104] getsockaddrarg() casts port number from int to short without any warning

[Roman Zeyde]

New submission from Roman Zeyde <roman.zeyde at gmail.com>:

The following code shouldn't fail without any warning at all:

>>> import socket
>>> s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>>> s.bind(('localhost', 70000))
>>> print(s.getsockname())
('127.0.0.1', 4464)

After looking through socketmodule.c (rev. 68450), it seems that AF_INET
case casts an "int port" into a "short addr->sin_port", and does not
checks for overflows:

	case AF_INET:
	{
		struct sockaddr_in* addr;
		char *host;
		int port, result;
		if (!PyTuple_Check(args)) {
			PyErr_Format(
				PyExc_TypeError,
				"getsockaddrarg: "
				"AF_INET address must be tuple, not %.500s",
				Py_TYPE(args)->tp_name);
			return 0;
		}
		if (!PyArg_ParseTuple(args, "eti:getsockaddrarg",
				      "idna", &host, &port))
			return 0;
		addr=(struct sockaddr_in*)addr_ret;
                result = setipaddr(host, (struct sockaddr *)addr,
                                   sizeof(*addr),  AF_INET);
                PyMem_Free(host);
                if (result < 0)
			return 0;
		addr->sin_family = AF_INET;
		addr->sin_port = htons((short)port);
		*len_ret = sizeof *addr;
		return 1;
	}

----------
components: None
messages: 80794
nosy: roman.zeyde
severity: normal
status: open
title: getsockaddrarg() casts port number from int to short without any warning
versions: Python 2.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue5104>
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