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set close-on-exec on all sockets so forked children can't inherit them #475

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Merged
astronomerdave merged 1 commit into from
Aug 1, 2026
+13 −6
Merged

set close-on-exec on all sockets so forked children can't inherit them #475

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19 changes: 13 additions & 6 deletions utils/network.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -137,7 +137,7 @@ namespace Network {

// now that there is a group and port, create the socket
//
if ( (this->fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 ) {
if ( (this->fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0)) == -1 ) {
errstm << "error " << errno << " creating socket: " << strerror(errno);
logwrite(function, errstm.str());
return(-1);
Expand Down Expand Up @@ -240,7 +240,7 @@ namespace Network {

// now that there is a group and port, create the socket
//
if ( ( this->fd = socket( AF_INET, SOCK_DGRAM, 0 ) ) < 0 ) {
if ( ( this->fd = socket( AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0 ) ) < 0 ) {
message << "error " << errno << " creating socket: " << strerror( errno );
logwrite(function, message.str());
return(-1);
Expand Down Expand Up @@ -563,10 +563,15 @@ namespace Network {
* Create new listening socket for pending connection on this->listenfd
* and returns a new connected socket this->fd
*
* accept4() with SOCK_CLOEXEC is used here rather than accept() because a
* descriptor from accept() never inherits close-on-exec from the listening
* socket, and setting it afterwards would leave a window in which a fork
* from another thread could inherit the connection.
*
*/
int TcpSocket::Accept() {
this->clilen = (socklen_t)sizeof(this->cliaddr);
this->fd = accept(this->listenfd, (struct sockaddr *) &this->cliaddr, &this->clilen);
this->fd = accept4(this->listenfd, (struct sockaddr *) &this->cliaddr, &this->clilen, SOCK_CLOEXEC);
if (this->fd < 0) { perror("(Network::TcpSocket::Accept) error calling accept"); return -1; }
return (this->fd);
}
Expand All @@ -586,9 +591,11 @@ namespace Network {
std::string function = "Network::TcpSocket::Listen";
std::stringstream errstm;

// create the socket
// create the socket, close-on-exec so that a process spawned by this one
// (E.G. Sequencer::Sequence::daemon_restart) cannot inherit the listening
// port and hold it after this process exits
//
if ( (this->listenfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1 ) {
if ( (this->listenfd = socket(PF_INET, SOCK_STREAM | SOCK_CLOEXEC, IPPROTO_TCP)) == -1 ) {
errstm << "error " << errno << " creating socket: " << strerror(errno);
logwrite(function, errstm.str());
return(-1);
Expand Down Expand Up @@ -731,7 +738,7 @@ namespace Network {
for (struct addrinfo *sa = this->addrs; sa != NULL; sa = sa->ai_next) {
// create the socket, which returns a file descriptor on success
//
this->fd = socket(sa->ai_family, sa->ai_socktype, sa->ai_protocol);
this->fd = socket(sa->ai_family, sa->ai_socktype | SOCK_CLOEXEC, sa->ai_protocol);

if (this->fd == -1) continue; // try another entry in the sock addr struct

Expand Down
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