[patch] net/rsync: problems in client name lookup code

[Wayne Davison]

On Thu, Apr 01, 2004 at 11:31:00AM -0500, Alex Vasylenko wrote:
> 	- detection of IPv6 via counting dots is plain silly and doesn't work;

Thanks, I've tweaked your patch for this a little and checked it in.
It's attached to this email.

> 	- fails to set ss_len member of struct sockaddr_storage, which when
> 	  passed to getnameinfo causes the latter to fail;

Not everyone has ss_len in sockaddr_storage, so this part of the patch
doesn't work.  It looked like the only place you set the value was after
calling client_sockaddr() (though you only affected one of the two
places it was called).  So, might it be better to set the value inside
the client_sockaddr() routine?

Attached is my guess at how this might be fixed.  This looks odd,
though, so I think this is probably not the right fix.  Can you (or
anyone with access to a system that uses ss_len) let me know if this
second patch is what we need, and if not, what the correct fix is.

Thanks,

..wayne..
-------------- next part --------------
--- clientname.c	1 Apr 2004 21:08:24 -0000	1.20
+++ clientname.c	1 Apr 2004 21:36:31 -0000
@@ -100,11 +100,7 @@ char *client_name(int fd)
 	static char name_buf[100];
 	static char port_buf[100];
 	static int initialised;
-	struct sockaddr_storage ss, *ssp;
-	struct sockaddr_in sin;
-#ifdef INET6
-	struct sockaddr_in6 sin6;
-#endif
+	struct sockaddr_storage ss;
 	socklen_t ss_len;
 
 	if (initialised)
@@ -113,43 +109,45 @@ char *client_name(int fd)
 	strcpy(name_buf, default_name);
 	initialised = 1;
 
+	memset(&ss, 0, sizeof ss);
+
 	if (am_server) {	/* daemon over --rsh mode */
 		char *addr = client_addr(fd);
-#ifdef INET6
-		int dots = 0;
-		char *p;
+		struct addrinfo hint, *answer;
+		int err;
+
+		memset(&hint, 0, sizeof hint);
 
-		for (p = addr; *p && (dots <= 3); p++) {
-			if (*p == '.')
-				dots++;
+		hint.ai_flags = AI_NUMERICHOST;
+		hint.ai_socktype = SOCK_STREAM;
+
+		if ((err = getaddrinfo(addr, NULL, &hint, &answer)) != 0) {
+			rprintf(FERROR, RSYNC_NAME ": malformed address %s: %s\n",
+			        addr, gai_strerror(err));
+			return name_buf;
 		}
-		if (dots > 3) {
-			/* more than 4 parts to IP address, must be ipv6 */
-			ssp = (struct sockaddr_storage *) &sin6;
-			ss_len = sizeof sin6;
-			memset(ssp, 0, ss_len);
-			inet_pton(AF_INET6, addr, &sin6.sin6_addr);
-			sin6.sin6_family = AF_INET6;
-		} else
+
+		switch (answer->ai_family) {
+		case AF_INET:
+			ss_len = sizeof (struct sockaddr_in);
+			memcpy(&ss, answer->ai_addr, ss_len);
+			break;
+#ifdef INET6
+		case AF_INET6:
+			ss_len = sizeof (struct sockaddr_in6);
+			memcpy(&ss, answer->ai_addr, ss_len);
+			break;
 #endif
-		{
-			ssp = (struct sockaddr_storage *) &sin;
-			ss_len = sizeof sin;
-			memset(ssp, 0, ss_len);
-			inet_pton(AF_INET, addr, &sin.sin_addr);
-			sin.sin_family = AF_INET;
 		}
-
+		freeaddrinfo(answer);
 	} else {
 		ss_len = sizeof ss;
-		ssp = &ss;
-
 		client_sockaddr(fd, &ss, &ss_len);
 	}
 
-	if (!lookup_name(fd, ssp, ss_len, name_buf, sizeof name_buf,
+	if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf,
 			port_buf, sizeof port_buf))
-		check_name(fd, ssp, name_buf);
+		check_name(fd, &ss, name_buf);
 
 	return name_buf;
 }
-------------- next part --------------
--- clientname.c	1 Apr 2004 21:39:35 -0000	1.21
+++ clientname.c	1 Apr 2004 22:00:22 -0000
@@ -190,9 +190,6 @@ void client_sockaddr(int fd,
 		memset(sin, 0, sizeof *sin);
 		sin->sin_family = AF_INET;
 		*ss_len = sizeof (struct sockaddr_in);
-#if HAVE_SOCKADDR_IN_LEN
-		sin->sin_len = *ss_len;
-#endif
 		sin->sin_port = sin6.sin6_port;
 
 		/* There is a macro to extract the mapped part
@@ -201,6 +198,10 @@ void client_sockaddr(int fd,
 		memcpy(&sin->sin_addr, &sin6.sin6_addr.s6_addr[12],
 		    sizeof sin->sin_addr);
 	}
+#endif /* INET6 */
+
+#if HAVE_SOCKADDR_IN_LEN
+	ss->ss_len = *ss_len;
 #endif
 }