+
+#ifdef USE_BTMP
+ /*
+ * Logs failed login attempts in _PATH_BTMP if that exists.
+ * The most common login failure is to give password instead of username.
+ * So the _PATH_BTMP file checked for the correct permission, so that
+ * only root can read it.
+ */
+
+void
+record_failed_login(const char *username, const char *hostname,
+ const char *ttyn)
+{
+ int fd;
+ struct utmp ut;
+ struct sockaddr_storage from;
+ socklen_t fromlen = sizeof(from);
+ struct sockaddr_in *a4;
+ struct sockaddr_in6 *a6;
+ time_t t;
+ struct stat fst;
+
+ if (geteuid() != 0)
+ return;
+ if ((fd = open(_PATH_BTMP, O_WRONLY | O_APPEND)) < 0) {
+ debug("Unable to open the btmp file %s: %s", _PATH_BTMP,
+ strerror(errno));
+ return;
+ }
+ if (fstat(fd, &fst) < 0) {
+ logit("%s: fstat of %s failed: %s", __func__, _PATH_BTMP,
+ strerror(errno));
+ goto out;
+ }
+ if((fst.st_mode & (S_IRWXG | S_IRWXO)) || (fst.st_uid != 0)){
+ logit("Excess permission or bad ownership on file %s",
+ _PATH_BTMP);
+ goto out;
+ }
+
+ memset(&ut, 0, sizeof(ut));
+ /* strncpy because we don't necessarily want nul termination */
+ strncpy(ut.ut_user, username, sizeof(ut.ut_user));
+ strlcpy(ut.ut_line, "ssh:notty", sizeof(ut.ut_line));
+
+ time(&t);
+ ut.ut_time = t; /* ut_time is not always a time_t */
+ ut.ut_type = LOGIN_PROCESS;
+ ut.ut_pid = getpid();
+
+ /* strncpy because we don't necessarily want nul termination */
+ strncpy(ut.ut_host, hostname, sizeof(ut.ut_host));
+
+ if (packet_connection_is_on_socket() &&
+ getpeername(packet_get_connection_in(),
+ (struct sockaddr *)&from, &fromlen) == 0) {
+ ipv64_normalise_mapped(&from, &fromlen);
+ if (from.ss_family == AF_INET) {
+ a4 = (struct sockaddr_in *)&from;
+ memcpy(&ut.ut_addr, &(a4->sin_addr),
+ MIN_SIZEOF(ut.ut_addr, a4->sin_addr));
+ }
+#ifdef HAVE_ADDR_V6_IN_UTMP
+ if (from.ss_family == AF_INET6) {
+ a6 = (struct sockaddr_in6 *)&from;
+ memcpy(&ut.ut_addr_v6, &(a6->sin6_addr),
+ MIN_SIZEOF(ut.ut_addr_v6, a6->sin6_addr));
+ }
+#endif
+ }
+
+ if (atomicio(vwrite, fd, &ut, sizeof(ut)) != sizeof(ut))
+ error("Failed to write to %s: %s", _PATH_BTMP,
+ strerror(errno));
+
+out:
+ close(fd);
+}
+#endif /* USE_BTMP */