Fix client_name to work on when INET6 is enabled but using a 4-part IPv4

[rsync/rsync.git] / clientname.c

diff --git a/clientname.c b/clientname.c
index 6602052..93ca68e 100644 (file)
--- a/clientname.c
+++ b/clientname.c
@@ -43,6 +43,7 @@ char *client_addr(int fd)
 {
        struct sockaddr_storage ss;
        socklen_t length = sizeof ss;
+       char *ssh_client, *p;
        static char addr_buf[100];
        static int initialised;
 
@@ -50,11 +51,20 @@ char *client_addr(int fd)
 
        initialised = 1;
 
-       client_sockaddr(fd, &ss, &length);
+       if ((ssh_client = getenv("SSH_CLIENT")) != NULL) {
+               strlcpy(addr_buf, ssh_client, sizeof(addr_buf));
+               /* truncate SSH_CLIENT to just IP address */
+               p = strchr(addr_buf, ' ');
+               if (p)
+                       *p = '\0';
+               else
+                       strlcpy(addr_buf, "0.0.0.0", sizeof("0.0.0.0"));
+       } else
+               client_sockaddr(fd, &ss, &length);
 
        getnameinfo((struct sockaddr *)&ss, length,
-                   addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
-       
+               addr_buf, sizeof(addr_buf), NULL, 0, NI_NUMERICHOST);
+
        return addr_buf;
 }
 
@@ -74,24 +84,66 @@ static int get_sockaddr_family(const struct sockaddr_storage *ss)
  * If anything goes wrong, including the name->addr->name check, then
  * we just use "UNKNOWN", so you can use that value in hosts allow
  * lines.
+ *
+ * After translation from sockaddr to name we do a forward lookup to
+ * make sure nobody is spoofing PTR records.
  **/
 char *client_name(int fd)
 {
-       struct sockaddr_storage ss;
-       socklen_t ss_len = sizeof ss;
        static char name_buf[100];
        static char port_buf[100];
        static int initialised;
+       struct sockaddr_storage *ssp;
+       socklen_t ss_len;
 
        if (initialised) return name_buf;
 
        strcpy(name_buf, default_name);
        initialised = 1;
 
-       client_sockaddr(fd, &ss, &ss_len);
+       if (getenv("SSH_CLIENT") != NULL) {
+               /* Look up name of IP address given in $SSH_CLIENT */
+               char *addr = client_addr(fd);
+               struct sockaddr_in sin;
+#ifdef INET6
+               int dots = 0;
+               char *p;
+               struct sockaddr_in6 sin6;
+
+               for (p = addr; *p && (dots < 3); p++) {
+                   if (*p == '.')
+                       dots++;
+               }
+               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.s6_addr);
+                       sin6.sin6_family = AF_INET6;
+               } else
+#endif
+               {
+                       ssp = (struct sockaddr_storage *) &sin;
+                       ss_len = sizeof sin;
+                       memset(ssp, 0, ss_len);
+                       inet_pton(AF_INET, addr, &sin.sin_addr.s_addr);
+                       sin.sin_family = AF_INET;
+               }
 
-       if (!lookup_name(fd, &ss, ss_len, name_buf, sizeof name_buf, port_buf, sizeof port_buf))
-               check_name(fd, &ss, name_buf, port_buf);
+       } else {
+               struct sockaddr_storage ss;
+
+               ss_len = sizeof ss;
+               ssp = &ss;
+
+               client_sockaddr(fd, &ss, &ss_len);
+
+       }
+
+       if (!lookup_name(fd, ssp, ss_len, name_buf, sizeof name_buf, 
+                       port_buf, sizeof port_buf))
+               check_name(fd, ssp, name_buf);
 
        return name_buf;
 }
@@ -149,6 +201,8 @@ void client_sockaddr(int fd,
 
 /**
  * Look up a name from @p ss into @p name_buf.
+ *
+ * @param fd file descriptor for client socket.
  **/
 int lookup_name(int fd, const struct sockaddr_storage *ss,
                socklen_t ss_len,
@@ -226,11 +280,14 @@ int compare_addrinfo_sockaddr(const struct addrinfo *ai,
  * @p ss -- otherwise we may be being spoofed.  If we suspect we are,
  * then we don't abort the connection but just emit a warning, and
  * change @p name_buf to be "UNKNOWN".
+ *
+ * We don't do anything with the service when checking the name,
+ * because it doesn't seem that it could be spoofed in any way, and
+ * getaddrinfo on random service names seems to cause problems on AIX.
  **/
 int check_name(int fd,
               const struct sockaddr_storage *ss,
-              char *name_buf,
-              const char *port_buf)
+              char *name_buf)
 {
        struct addrinfo hints, *res, *res0;
        int error;
@@ -240,7 +297,7 @@ int check_name(int fd,
        hints.ai_family = ss_family;
        hints.ai_flags = AI_CANONNAME;
        hints.ai_socktype = SOCK_STREAM;
-       error = getaddrinfo(name_buf, port_buf, &hints, &res0);
+       error = getaddrinfo(name_buf, NULL, &hints, &res0);
        if (error) {
                rprintf(FERROR,
                        RSYNC_NAME ": forward name lookup for %s failed: %s\n",