Fix more ident lookup bugs

[michaelortmann]

Found by: michaelortmann
Patch by: michaelortmann
Fixes:

One-line summary:
Fix more ident lookup bugs

Additional description (if needed):

If a socket is set O_NONBLOCK and connect() returns EINPROGRESS, it must be checked for ECONNREFUSED.
Here, this was done properly:

eggdrop/src/net.c

Lines 560 to 580 in 2a6a368

	rc = connect(sock, &addr->addr.sa, addr->addrlen);
	/* To minimize a proven race condition, call ident here (especially when
	* rc < 0 and errno == EINPROGRESS)
	*/
	if (dcc[i].status & STAT_SERV) {
	check_tcl_event("ident");
	}
	if (rc < 0) {
	if (errno == EINPROGRESS) {
	/* Async connection... don't return socket descriptor
	* until after we confirm if it was successful or not */
	tv.tv_sec = 1;
	tv.tv_usec = 0;
	FD_ZERO(&sockset);
	FD_SET(sock, &sockset);
	select(sock + 1, &sockset, NULL, NULL, &tv);
	res_len = sizeof(res);
	getsockopt(sock, SOL_SOCKET, SO_ERROR, &res, &res_len);
	if (res == EINPROGRESS) /* Operation now in progress */
	return sock; /* This could probably fail somewhere */
	if (res == ECONNREFUSED) { /* Connection refused */

But here it was not and a write was committed:

eggdrop/src/dcc.c

Lines 1383 to 1404 in 2a6a368

	if (connect(dcc[j].sock, &dcc[j].sockname.addr.sa,
	dcc[j].sockname.addrlen) < 0 && (errno != EINPROGRESS)) {
	killsock(dcc[j].sock);
	lostdcc(j);
	putlog(LOG_MISC, "*", DCC_IDENTFAIL, dcc[i].host, strerror(errno));
	j = 0;
	}
	sock = dcc[j].sock;
	}
	}
	if (j < 0) {
	dcc_telnet_got_ident(i, userhost);
	return;
	}
	dcc[j].sock = sock;
	dcc[j].port = 113;
	dcc[j].addr = dcc[i].addr;
	strcpy(dcc[j].host, dcc[i].host);
	strcpy(dcc[j].nick, "*");
	dcc[j].u.ident_sock = dcc[i].sock;
	dcc[j].timeval = now;
	dprintf(j, "%d, %d\n", dcc[i].port, dcc[idx].port);

Additionally O_NONBLOCK is POSIX 2001 and old quirk code is removed, see: https://www.gaertner.de/~neitzel/susv3/basedefs/fcntl.h.html

Additionally also the proper code mentioned above had an issue, it did select() with an arbitrary timeout of 1 sec, when it should be nonblocking.

Additionally there was a bug here:

eggdrop/src/dcc.c

Lines 1388 to 1403 in 2a6a368

	j = 0;
	}
	sock = dcc[j].sock;
	}
	}
	if (j < 0) {
	dcc_telnet_got_ident(i, userhost);
	return;
	}
	dcc[j].sock = sock;
	dcc[j].port = 113;
	dcc[j].addr = dcc[i].addr;
	strcpy(dcc[j].host, dcc[i].host);
	strcpy(dcc[j].nick, "*");
	dcc[j].u.ident_sock = dcc[i].sock;
	dcc[j].timeval = now;

Were this line j = 0 ever executed, the gates of tartaros would have opened for dcc[0].

Test cases demonstrating functionality (if applicable):
Without this fix:
When telnetting to the bot and the user has no identd running, the bot would log like:

[21:01:18] Telnet connection: localhost.home.arpa/45052
[21:01:18] net: eof!(write) socket 13 (Broken pipe,32)

With this fix:
Test without identd:

[12:24:02] Telnet connection: localhost.home.arpa/52216
[12:24:02] net: attempted socket connection refused: 127.0.0.1:113
[12:24:02] Ident failed for localhost.home.arpa: Connection refused
[12:24:09] pbkdf2 method SHA256 rounds 16000, user 12.493ms sys 0.416ms
[12:24:09] Logged in: testuser (telnet@localhost.home.arpa/52216)
*** testuser joined the party line.

Test wih identd:

[12:24:25] Telnet connection: localhost.home.arpa/42944
[12:24:28] pbkdf2 method SHA256 rounds 16000, user 16.223ms sys 6.315ms
[12:24:28] Logged in: testuser (michael@localhost.home.arpa/42944)
*** testuser joined the party line.

Additionally i applied this patch to windrop and it also works under cygwin.

[michaelortmann]

Maybe related/fixing #809?

[vanosg]

Please resolve conflicts, thanks

[michaelortmann]

Please resolve conflicts, thanks

done. ready for review again.