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
@@ -1572,6 +1572,7 @@ 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;
@@ -1579,6 +1580,7 @@ sock_accept(PySocketSockObject *s)
 
     if (!getsockaddrlen(s, &addrlen))
         return NULL;
+    buflen = addrlen;
     memset(&addrbuf, 0, addrlen);
 
     if (!IS_SELECTABLE(s))
@@ -1605,7 +1607,7 @@ 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;
 
@@ -2055,17 +2057,19 @@ 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,
-                        s->sock_proto);
+    return makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
+                        (addrlen > buflen) ? buflen : addrlen, s->sock_proto);
 }
 
 PyDoc_STRVAR(getsockname_doc,
@@ -2084,17 +2088,19 @@ 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,
-                        s->sock_proto);
+    return makesockaddr(s->sock_fd, SAS2SA(&addrbuf),
+                        (addrlen > buflen) ? buflen : addrlen, s->sock_proto);
 }
 
 PyDoc_STRVAR(getpeername_doc,
@@ -2354,11 +2360,13 @@ sock_recvfrom_guts(PySocketSockObject *s
     int timeout;
     Py_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();
@@ -2394,7 +2402,8 @@ 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;