From f1ec26a07ce7b93b19dab0f9f330f01205bc4e82 Mon Sep 17 00:00:00 2001
From: binki <devnull@localhost>
Date: Fri, 28 May 2010 04:30:22 +0000
Subject: [PATCH] - Partially fixed bug where IPv4 addresses were randomly
 mishandled by the cgiirc code, resulting in the sockhost/hostmask being set
 to something like ::ffff:127.0.0.1, which confused the s2s protocol. Reported
 by tabrisnet (#0003907). Also, reject incorrectly formed hostnames from
 WEBIRC command.

---
 Changes              |  4 ++++
 include/h.h          |  1 +
 src/modules/m_pass.c | 39 +++++++++++++++++++++++++--------------
 src/res.c            |  5 +++++
 src/s_bsd.c          |  2 +-
 src/socket.c         |  3 +++
 6 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/Changes b/Changes
index 1dc23c985..84ed2b5f4 100644
--- a/Changes
+++ b/Changes
@@ -1971,3 +1971,7 @@
 - Fixed bug in CVS where the ban exempt (+e) handling was reversed: if a
   non-matching +e was present, one could walk through bans. Reported by
   tabrisnet (#0003909). Bug was caused by chained/stacked extbans.
+- Partially fixed bug where IPv4 addresses were randomly mishandled by the
+  cgiirc code, resulting in the sockhost/hostmask being set to something like
+  ::ffff:127.0.0.1, which confused the s2s protocol. Reported by tabrisnet
+  (#0003907). Also, reject incorrectly formed hostnames from WEBIRC command.
diff --git a/include/h.h b/include/h.h
index ee68650da..fce954c70 100644
--- a/include/h.h
+++ b/include/h.h
@@ -256,6 +256,7 @@ extern int get_sockerr(aClient *);
 extern int inetport(aClient *, char *, int);
 extern void init_sys();
 extern void init_modef();
+extern int verify_hostname(char *name);
 
 #ifdef NO_FDLIST
 extern int read_message(time_t);
diff --git a/src/modules/m_pass.c b/src/modules/m_pass.c
index ca03f9fc8..76c2ba688 100644
--- a/src/modules/m_pass.c
+++ b/src/modules/m_pass.c
@@ -148,8 +148,9 @@ ConfigItem_ban *bconf;
 int docgiirc(aClient *cptr, char *ip, char *host)
 {
 #ifdef INET6
-char ipbuf[64], crap[32];
+	char ipbuf[64];
 #endif
+	char *sockhost;
 
 	if (IsCGIIRC(cptr))
 		return exit_client(cptr, cptr, &me, "Double CGI:IRC request (already identified)");
@@ -157,18 +158,20 @@ char ipbuf[64], crap[32];
 	if (host && !strcmp(ip, host))
 		host = NULL; /* host did not resolve, make it NULL */
 
-	/* STEP 1: Update cptr->ip */
-#ifdef INET6
-	/* Transform ipv4 to ::ffff:ipv4 if needed */
-	if (inet_pton(AF_INET, ip, crap) != 0)
+	/* STEP 1: Update cptr->ip
+	   inet_pton() returns 1 on success, 0 on bad input, -1 on bad AF */
+	if(inet_pton(AFINET, ip, &cptr->ip) != 1)
 	{
-		snprintf(ipbuf, sizeof(ipbuf), "::ffff:%s", ip);
-		ip = ipbuf;
-	}
-#endif
-
-	if (inet_pton(AFINET, ip, &cptr->ip) <= 0)
+#ifndef INET6
+		/* then we have an invalid IP */
 		return exit_client(cptr, cptr, &me, "Invalid IP address");
+#else
+		/* The address may be IPv4. We have to try ::ffff:ipv4 */
+		snprintf(ipbuf, sizeof(ipbuf), "::ffff:%s", ip);
+		if(inet_pton(AFINET, ipbuf, &cptr->ip) != 1)
+			return exit_client(cptr, cptr, &me, "Invalid IP address");
+#endif
+	}
 
 	/* STEP 2: Update GetIP() */
 	if (cptr->user)
@@ -187,11 +190,19 @@ char ipbuf[64], crap[32];
 		cptr->hostp = NULL;
 	}
 	/* (create new) */
-	if (host)
+	if (host && verify_hostname(host))
 		cptr->hostp = unreal_create_hostent(host, &cptr->ip);
 
-	/* STEP 4: Update sockhost */		
-	strlcpy(cptr->sockhost, ip, sizeof(cptr->sockhost));
+	/* STEP 4: Update sockhost
+	   Make sure that if this any IPv4 address is _not_ prefixed with
+	   "::ffff:" by using Inet_ia2p().
+	 */
+	sockhost = Inet_ia2p(&cptr->ip);
+	if(!sockhost)
+	{
+		return exit_client(cptr, cptr, &me, "Error processing CGI:IRC IP address.");
+	}
+	strlcpy(cptr->sockhost, sockhost, sizeof(cptr->sockhost));
 
 	SetCGIIRC(cptr);
 
diff --git a/src/res.c b/src/res.c
index 38e4618dd..3a3213dcf 100644
--- a/src/res.c
+++ b/src/res.c
@@ -282,6 +282,11 @@ char ipv6 = r->ipv6;
 #endif
 }
 
+/*
+  returns:
+  1 = good hostname
+  0 = bad hostname
+ */
 int verify_hostname(char *name)
 {
 char *p;
diff --git a/src/s_bsd.c b/src/s_bsd.c
index c4a0d5f46..ff49081ee 100644
--- a/src/s_bsd.c
+++ b/src/s_bsd.c
@@ -1041,7 +1041,7 @@ void set_sock_opts(int fd, aClient *cptr)
 	/* We deal with both IPv4 and IPv6 in one (listen) socket.
 	 * This used to be on by default, but FreeBSD, and much later Linux
 	 * sometimes as well, seem to default it to IPv6 only ('1').
-	 * We now have this new fancy option to turn it on in Unreal,
+	 * We now have this new fancy option to turn it off in Unreal,
 	 * instead of requiring our users to sysctl.
 	 */
 	opt = 0;
diff --git a/src/socket.c b/src/socket.c
index 8c1d69f1f..eb004a0dc 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -199,6 +199,9 @@ char	*Inet_si2p(struct SOCKADDR_IN *sin)
 	return (Inet_si2pB(sin, buf, sizeof(buf)));
 }
 
+/*
+  May return NULL if inet_ntop() fails.
+ */
 char	*Inet_ia2p(struct IN_ADDR *ia)
 {
 #ifndef INET6