At least in 2.5.2, there appear to be only two places in the standard 
library where an arbitrary and unchecked size is passed directly to 
_socketobject.recv.  _fileobject.read is one such place and the other 
is in logging/config.py.  In both cases, the pattern is something like

while len(data) < size:
    data = data + sock.recv(size - len(data))

Of course, the same pattern may exist in any number of instances of 
user code that performs a socket.recv, and all of these would be 
subject to the same memory thrashing problem that originally beset 
imaplib.

As such, I now agree with Ralf that the fix ultimately belongs in 
_socketobject.  However, deploying a fix for 2.5.2 is probably easier 
if it's in socket.py than if it requires a recompile.