commit 1f4711a5474d2f0ea4664bd9b54f036af11f96cd
from: Alexander Barton <alex@barton.de>
date: Mon Jan 16 10:43:22 2012 UTC

Implement user mode 'C': require "same channel" to send message

If the target user of a PRIVMSG or NOTICE command has the user mode 'C'
set, it is required that both sender and receiver are on the same channel.

This prevents private flooding by completely unknown clients.

commit - 4d0069c3a8021c32b5bdeeec57f1d41d369587ce
commit + 1f4711a5474d2f0ea4664bd9b54f036af11f96cd
blob - 20e927b6e681a9743b9ae0854001cdca2959556e
blob + 0b0e488f46b212a306ec7ba01e694bf87575fe22
--- doc/Modes.txt
+++ doc/Modes.txt
@@ -23,6 +23,7 @@ channels he is using at the moment.
 
   a	0.3.0	User is away.
   c	17	IRC operator wants to receive connect/disconnect NOTICEs.
+  C	19	Only users that share a channel are allowed to send messages.
   i	0.0.1	User is "invisible".
   o	0.0.1	User is IRC operator.
   r	0.0.1	User is restricted.
blob - e7a14ef88959069a67f7ecb8f53c7c03c5b2071f
blob + 9dc5e92d4f4ec074247bd9f2741a8e4431b3b79f
--- src/ngircd/defines.h
+++ src/ngircd/defines.h
@@ -158,7 +158,7 @@
 #endif
 
 /** Supported user modes. */
-#define USERMODES "aciorRswx"
+#define USERMODES "acCiorRswx"
 
 /** Supported channel modes. */
 #define CHANMODES "biIklmnoOPRstvz"
blob - c85faa04d626f42569fe83c2a7e852bdeb768062
blob + 3dd61e7ca2031ad6727c64579da300b86cd9a038
--- src/ngircd/irc-mode.c
+++ src/ngircd/irc-mode.c
@@ -214,6 +214,7 @@ Client_Mode( CLIENT *Client, REQUEST *Req, CLIENT *Ori
 		/* Validate modes */
 		x[0] = '\0';
 		switch (*mode_ptr) {
+		case 'C': /* Only messages from clients sharing a channel */
 		case 'i': /* Invisible */
 		case 's': /* Server messages */
 		case 'w': /* Wallops messages */
blob - 10e3e45656bdb1cc996ef0d92ad2c0a1cd8fab2f
blob + 2b94e33ac229b44cf509277c23944034bebf5a51
--- src/ngircd/irc.c
+++ src/ngircd/irc.c
@@ -349,6 +349,7 @@ static bool
 Send_Message(CLIENT * Client, REQUEST * Req, int ForceType, bool SendErrors)
 {
 	CLIENT *cl, *from;
+	CL2CHAN *cl2chan;
 	CHANNEL *chan;
 	char *currentTarget = Req->argv[0];
 	char *lastCurrentTarget = NULL;
@@ -485,6 +486,23 @@ Send_Message(CLIENT * Client, REQUEST * Req, int Force
 			}
 #endif
 
+			if (Client_HasMode(cl, 'C')) {
+				cl2chan = Channel_FirstChannelOf(cl);
+				while (cl2chan) {
+					chan = Channel_GetChannel(cl2chan);
+					if (Channel_IsMemberOf(chan, from))
+						break;
+					cl2chan = Channel_NextChannelOf(cl, cl2chan);
+				}
+				if (!cl2chan) {
+					if (SendErrors && !IRC_WriteStrClient(
+					    from, ERR_NOTONSAMECHANNEL_MSG,
+					    Client_ID(from), Client_ID(cl)))
+						return DISCONNECTED;
+					goto send_next_target;
+				}
+			}
+
 			if (SendErrors && (Client_Type(Client) != CLIENT_SERVER)
 			    && strchr(Client_Modes(cl), 'a')) {
 				/* Target is away */
@@ -522,6 +540,7 @@ Send_Message(CLIENT * Client, REQUEST * Req, int Force
 				return DISCONNECTED;
 		}
 
+	send_next_target:
 		currentTarget = strtok_r(NULL, ",", &lastCurrentTarget);
 		if (currentTarget)
 			Conn_SetPenalty(Client_Conn(Client), 1);
blob - 0070e70159f46bd533624e953225854e23975812
blob + 6a784fe9eb97a98ebc8194bee63232e7893f6c82
--- src/ngircd/messages.h
+++ src/ngircd/messages.h
@@ -134,6 +134,7 @@
 #define ERR_CANTKILLSERVER_MSG		"483 %s :You can't kill a server!"
 #define ERR_RESTRICTED_MSG		"484 %s :Your connection is restricted"
 #define ERR_NOOPERHOST_MSG		"491 %s :Not configured for your host"
+#define ERR_NOTONSAMECHANNEL_MSG	"493 %s :You must share a common channel with %s"
 
 #define ERR_UMODEUNKNOWNFLAG_MSG	"501 %s :Unknown mode"
 #define ERR_UMODEUNKNOWNFLAG2_MSG	"501 %s :Unknown mode \"%c%c\""