telnetd: if FEATURE_IPV6 is on, telnet will NOT work on IPv4

which is kind of stupid

1 files changed, 65 insertions, 21 deletions

diff --git a/networking/telnetd.c b/networking/telnetd.c
index 549488507..d524ac891 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -37,10 +37,8 @@
 #define BUFSIZE 4000
 
 #if ENABLE_FEATURE_IPV6
-#define SOCKET_TYPE	AF_INET6
 typedef struct sockaddr_in6 sockaddr_type;
 #else
-#define SOCKET_TYPE	AF_INET
 typedef struct sockaddr_in sockaddr_type;
 #endif
 
@@ -357,31 +355,77 @@ free_session(struct tsession *ts)
 }
 
 static int
-create_socket(int port, const char *opt_bindaddr)
+dotted2sockaddr(const char *dotted, struct sockaddr* sp, int socklen)
+{
+	union {
+		struct in_addr a4;
+#if ENABLE_FEATURE_IPV6
+		struct in6_addr a6;
+#endif
+	} a;
+
+#if ENABLE_FEATURE_IPV6
+	if (socklen >= sizeof(struct sockaddr_in6)
+	 && inet_pton(AF_INET6, dotted, &a) > 0
+	) {
+		((struct sockaddr_in6*)sp)->sin6_family = AF_INET6;
+		((struct sockaddr_in6*)sp)->sin6_addr = a.a6;
+	} else
+#endif
+	if (socklen >= sizeof(struct sockaddr_in)
+	 && inet_pton(AF_INET, dotted, &a) > 0
+	) {
+		((struct sockaddr_in*)sp)->sin_family = AF_INET;
+		((struct sockaddr_in*)sp)->sin_addr = a.a4;
+	} else
+		return 1;
+
+	return 0; /* success */
+}
+
+static int
+xsocket_stream_ip4or6(sa_family_t *fp)
+{
+	int fd = socket(AF_INET6, SOCK_STREAM, 0);
+	if (fp) *fp = AF_INET6;
+	if (fd < 0) {
+		fd = xsocket(AF_INET, SOCK_STREAM, 0);
+		if (fp) *fp = AF_INET;
+	}
+	return fd;
+}
+
+static int
+create_socket(const char *hostaddr, int port)
 {
 	static const int on = 1;
 	int fd;
-	sockaddr_type sa;
-#if !ENABLE_FEATURE_IPV6
-	struct in_addr bind_addr = { .s_addr = 0x0 };
+	union {
+		struct sockaddr sa;
+		struct sockaddr_in sin;
+#if ENABLE_FEATURE_IPV6
+		struct sockaddr_in6 sin6;
+#endif
+	} sa;
 
-	/* TODO: generic string -> sockaddr converter */
-	if (opt_bindaddr && inet_aton(opt_bindaddr, &bind_addr) == 0)
+	memset(&sa, 0, sizeof(sa));
+	if (hostaddr && dotted2sockaddr(hostaddr, &sa.sa, sizeof(sa)))
 		bb_show_usage();
-#endif
-	fd = xsocket(SOCKET_TYPE, SOCK_STREAM, 0);
+
+	if (!sa.sa.sa_family)
+		fd = xsocket_stream_ip4or6(&sa.sa.sa_family);
+	else /* user specified -b ADDR dictates family */
+		fd = xsocket(sa.sa.sa_family, SOCK_STREAM, 0);
 	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
-	memset((void *)&sa, 0, sizeof(sa));
+
 #if ENABLE_FEATURE_IPV6
-	sa.sin6_family = AF_INET6;
-	sa.sin6_port = htons(port);
-	/* sa.sin6_addr = bind_addr6; */
-#else
-	sa.sin_family = AF_INET;
-	sa.sin_port = htons(port);
-	sa.sin_addr = bind_addr;
+	if (sa.sa.sa_family == AF_INET6)
+		sa.sin6.sin6_port = htons(port);
 #endif
-	xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
+	if (sa.sa.sa_family == AF_INET)
+		sa.sin.sin_port = htons(port);
+
+	xbind(fd, &sa.sa, sizeof(sa));
 	xlisten(fd, 1);
 	return fd;
 }
@@ -390,7 +434,7 @@ create_socket(int port, const char *opt_bindaddr)
 
 /* Never actually called */
 void free_session(struct tsession *ts);
-int create_socket(int port, const char *opt_bindaddr);
+int create_socket(const char *hostaddr, int port);
 
 #endif
 
@@ -447,7 +491,7 @@ telnetd_main(int argc, char **argv)
 	if (IS_INETD) {
 		sessions = make_new_session(0, 1);
 	} else {
-		master_fd = create_socket(portnbr, opt_bindaddr);
+		master_fd = create_socket(opt_bindaddr, portnbr);
 		if (!(opt & OPT_FOREGROUND))
 			xdaemon(0, 0);
 	}