If accept(), etc. return a larger addrlen than was supplied,
ignore it and use the original buffer length.

diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -1573,6 +1573,7 @@ sock_accept(PySocketSockObject *s)
 	sock_addr_t addrbuf;
 	SOCKET_T newfd = INVALID_SOCKET;
 	socklen_t addrlen;
+	socklen_t buflen;
 	PyObject *sock = NULL;
 	PyObject *addr = NULL;
 	PyObject *res = NULL;
@@ -1580,6 +1581,7 @@ sock_accept(PySocketSockObject *s)
 
 	if (!getsockaddrlen(s, &addrlen))
 		return NULL;
+	buflen = addrlen;
 	memset(&addrbuf, 0, addrlen);
 
 	if (!IS_SELECTABLE(s))
@@ -1606,7 +1608,8 @@ sock_accept(PySocketSockObject *s)
 	}
 
 	addr = makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
-			    addrlen, s->sock_proto);
+			    (addrlen > buflen) ? buflen : addrlen,
+			    s->sock_proto);
 	if (addr == NULL)
 		goto finally;
 
@@ -2040,16 +2043,19 @@ sock_getsockname(PySocketSockObject *s)
 	sock_addr_t addrbuf;
 	int res;
 	socklen_t addrlen;
+	socklen_t buflen;
 
 	if (!getsockaddrlen(s, &addrlen))
 		return NULL;
+	buflen = addrlen;
 	memset(&addrbuf, 0, addrlen);
 	Py_BEGIN_ALLOW_THREADS
 	res = getsockname(s->sock_fd, SAS2SA(&addrbuf), &addrlen);
 	Py_END_ALLOW_THREADS
 	if (res < 0)
 		return s->errorhandler();
-	return makesockaddr(s->sock_fd, SAS2SA(&addrbuf), addrlen,
+	return makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
+			    (addrlen > buflen) ? buflen : addrlen,
 			    s->sock_proto);
 }
 
@@ -2069,16 +2075,19 @@ sock_getpeername(PySocketSockObject *s)
 	sock_addr_t addrbuf;
 	int res;
 	socklen_t addrlen;
+	socklen_t buflen;
 
 	if (!getsockaddrlen(s, &addrlen))
 		return NULL;
+	buflen = addrlen;
 	memset(&addrbuf, 0, addrlen);
 	Py_BEGIN_ALLOW_THREADS
 	res = getpeername(s->sock_fd, SAS2SA(&addrbuf), &addrlen);
 	Py_END_ALLOW_THREADS
 	if (res < 0)
 		return s->errorhandler();
-	return makesockaddr(s->sock_fd, SAS2SA(&addrbuf), addrlen,
+	return makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
+			    (addrlen > buflen) ? buflen : addrlen,
 			    s->sock_proto);
 }
 
@@ -2340,11 +2349,13 @@ sock_recvfrom_guts(PySocketSockObject *s
 	int timeout;
 	ssize_t n = -1;
 	socklen_t addrlen;
+	socklen_t buflen;
 
 	*addr = NULL;
 
 	if (!getsockaddrlen(s, &addrlen))
 		return -1;
+	buflen = addrlen;
 
 	if (!IS_SELECTABLE(s)) {
 		select_error();
@@ -2380,7 +2391,8 @@ sock_recvfrom_guts(PySocketSockObject *s
 	}
 
 	if (!(*addr = makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
-				   addrlen, s->sock_proto)))
+				   (addrlen > buflen) ? buflen : addrlen,
+				   s->sock_proto)))
 		return -1;
 
 	return n;