luad

commit 12c7abd3b0299395bb5071cf9313cf45ac896cdb
parent 0d7dfa957070d4c6311472f595846d36873befc3
Author: Daniel Barlow <dan@telent.net>
Date:   Mon,  1 Jun 2026 14:11:45 +0100

if message exceeds buffer size, disconnect instead of running lua

Diffstat:
M
luad.c
 | 
21
++++++++++++++-------

1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/luad.c b/luad.c
@@ -192,6 +192,12 @@ struct peer_entry* find_peer(pid_t pid) {
     return NULL;
 }
 
+void hangup_peer(int socket, struct sockaddr_un * peer_addr,
+                 size_t peer_addr_len,
+                 uint32_t retval) {
+    sendto(socket, (void *) &retval, 4, 0, (struct sockaddr *) peer_addr, peer_addr_len);
+}
+
 int main(int argc, char **argv)
 {
     int status;
@@ -256,7 +262,7 @@ int main(int argc, char **argv)
         if(pollfds[0].revents) {
             if(find_peer(0)) {
                 int len = recvmsg(socket, &msg , 0);
-                if(len<=0) continue;
+                if(len <= 0) continue;
 
                 int peer_fds[3];
                 if(fds_from_msg(&msg, peer_fds)) {
@@ -266,9 +272,12 @@ int main(int argc, char **argv)
                     }
                     memmove(argline, buf, len);
 
-                    pid_t child_pid = fork_lua(L, argline, len, peer_fds);
-                    register_peer(child_pid, &peer_addr, msg.msg_namelen);
-
+                    if(msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) {
+                        hangup_peer(socket, &peer_addr, msg.msg_namelen, 0xffff);
+                    } else {
+                        pid_t child_pid = fork_lua(L, argline, len, peer_fds);
+                        register_peer(child_pid, &peer_addr, msg.msg_namelen);
+                    }
                     /* close peer fds in parent */
                     close(peer_fds[0]);
                     close(peer_fds[1]);
@@ -293,9 +302,7 @@ int main(int argc, char **argv)
                     } else if(WIFSIGNALED(wstatus)) {
                         ret = htonl(128 + WTERMSIG(wstatus));
                     }
-                    sendto(socket, (void *) &ret, 4, 0,
-                           (const struct sockaddr *) &(peer->addr),
-                           peer->addrlen);
+                    hangup_peer(socket, &(peer->addr), peer->addrlen, ret);
                     peer->pid = 0;
                 }
             }