Problem - Kevin Tafuro

if (socketpool_limit > 0 && socketpool_used >= socketpool_limit) {
if (!block) {
avail = 0;
errno = EMFILE;
} else {
while (socketpool_limit > 0 && socketpool_used >= socketpool_limit)
SPC_WAIT_COND(socketpool_cond, socketpool_mutex);
}
}
if (avail && (new_sd = socket(domain, type, protocol)) != -1)
socketpool_used++;
SPC_CLEANUP_POP(1);
return new_sd;
}
When a socket that was obtained using spc_socketpool_accept( ) or spc_socketpool_
socket( ) is no longer needed, close it by calling spc_socketpool_close( ). Do not call
spc_socketpool_close( ) with file or socket descriptors that were not obtained from
one of the wrapper functions; otherwise, the socket count will become corrupted.
This implementation does not keep a list of the actual descriptors that have been
allocated, so it is the responsibility of the caller to do so. If a socket being closed
makes room for another socket to be created, the condition that the accept( ) and
socket( ) wrapper functions wait on will be signaled.
int spc_socketpool_close(int sd) {
if (closesocket(sd) = = SOCKET_ERROR) return -1;
SPC_ACQUIRE_MUTEX(socketpool_mutex);
if (socketpool_limit > 0 && socketpool_used = = socketpool_limit)
SPC_SIGNAL_COND(socketpool_cond);
socketpool_used--;
SPC_RELEASE_MUTEX(socketpool_mutex);
return 0;
}
13.9 Guarding Against Resource Starvation
Attacks on Unix
Problem
You need to prevent resource starvation attacks against your application.
Solution
The operating system does not trust the applications that it allows to run. For this
reason, the operating system imposes limits on certain resources. The limitations are
imposed to prevent an application from using up all of the available system
resources, thus denying other running applications the ability to run. The default
Guarding Against Resource Starvation Attacks on Unix | 727
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