+static char ttyline[20];
+
+/*
+ * Helper function for sgetpwnam().
+ */
+char *
+sgetsave(s)
+ char *s;
+{
+ char *malloc();
+ char *new = malloc((unsigned) strlen(s) + 1);
+
+ if (new == NULL) {
+ perror_reply(421, "Local resource failure: malloc");
+ dologout(1);
+ /* NOTREACHED */
+ }
+ (void) strcpy(new, s);
+ return (new);
+}
+
+/*
+ * Save the result of a getpwnam. Used for USER command, since
+ * the data returned must not be clobbered by any other command
+ * (e.g., globbing).
+ */
+struct passwd *
+sgetpwnam(name)
+ char *name;
+{
+ static struct passwd save;
+ register struct passwd *p;
+ char *sgetsave();
+
+ if ((p = getpwnam(name)) == NULL)
+ return (p);
+ if (save.pw_name) {
+ free(save.pw_name);
+ free(save.pw_passwd);
+ free(save.pw_gecos);
+ free(save.pw_dir);
+ free(save.pw_shell);
+ }
+ save = *p;
+ save.pw_name = sgetsave(p->pw_name);
+ save.pw_passwd = sgetsave(p->pw_passwd);
+ save.pw_gecos = sgetsave(p->pw_gecos);
+ save.pw_dir = sgetsave(p->pw_dir);
+ save.pw_shell = sgetsave(p->pw_shell);
+ return (&save);
+}
+
+int login_attempts; /* number of failed login attempts */
+int askpasswd; /* had user command, ask for passwd */
+
+/*
+ * USER command.
+ * Sets global passwd pointer pw if named account exists and is acceptable;
+ * sets askpasswd if a PASS command is expected. If logged in previously,
+ * need to reset state. If name is "ftp" or "anonymous", the name is not in
+ * _PATH_FTPUSERS, and ftp account exists, set guest and pw, then just return.
+ * If account doesn't exist, ask for passwd anyway. Otherwise, check user
+ * requesting login privileges. Disallow anyone who does not have a standard
+ * shell as returned by getusershell(). Disallow anyone mentioned in the file
+ * _PATH_FTPUSERS to allow people such as root and uucp to be avoided.
+ */
+user(name)
+ char *name;
+{
+ register char *cp;
+ char *shell;
+ char *getusershell();
+
+ if (logged_in) {
+ if (guest) {
+ reply(530, "Can't change user from guest login.");
+ return;
+ }
+ end_login();
+ }
+
+ guest = 0;
+ if (strcmp(name, "ftp") == 0 || strcmp(name, "anonymous") == 0) {
+ if (checkuser("ftp") || checkuser("anonymous"))
+ reply(530, "User %s access denied.", name);
+ else if ((pw = sgetpwnam("ftp")) != NULL) {
+ guest = 1;
+ askpasswd = 1;
+ reply(331, "Guest login ok, send ident as password.");
+ } else
+ reply(530, "User %s unknown.", name);
+ return;
+ }
+ if (pw = sgetpwnam(name)) {
+ if ((shell = pw->pw_shell) == NULL || *shell == 0)
+ shell = _PATH_BSHELL;
+ while ((cp = getusershell()) != NULL)
+ if (strcmp(cp, shell) == 0)
+ break;
+ endusershell();
+ if (cp == NULL || checkuser(name)) {
+ reply(530, "User %s access denied.", name);
+ if (logging)
+ syslog(LOG_NOTICE,
+ "FTP LOGIN REFUSED FROM %s, %s",
+ remotehost, name);
+ pw = (struct passwd *) NULL;
+ return;
+ }
+ }
+ reply(331, "Password required for %s.", name);
+ askpasswd = 1;
+ /*
+ * Delay before reading passwd after first failed
+ * attempt to slow down passwd-guessing programs.
+ */
+ if (login_attempts)
+ sleep((unsigned) login_attempts);
+}
+
+/*
+ * Check if a user is in the file _PATH_FTPUSERS
+ */
+checkuser(name)
+ char *name;
+{
+ register FILE *fd;
+ register char *p;
+ char line[BUFSIZ];
+
+ if ((fd = fopen(_PATH_FTPUSERS, "r")) != NULL) {
+ while (fgets(line, sizeof(line), fd) != NULL)
+ if ((p = index(line, '\n')) != NULL) {
+ *p = '\0';
+ if (line[0] == '#')
+ continue;
+ if (strcmp(line, name) == 0)
+ return (1);
+ }
+ (void) fclose(fd);
+ }
+ return (0);
+}
+
+/*
+ * Terminate login as previous user, if any, resetting state;
+ * used when USER command is given or login fails.
+ */
+end_login()
+{
+
+ (void) seteuid((uid_t)0);
+ if (logged_in)
+ logwtmp(ttyline, "", "");
+ pw = NULL;
+ logged_in = 0;
+ guest = 0;
+}
+
projects / unix-history / blobdiff