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$NetBSD: patch-ai,v 1.4 2008/06/07 20:22:18 tonnerre Exp $
--- appl/telnet/telnetd/sys_term.c.orig 2008-06-07 15:55:51.000000000 +0200
+++ appl/telnet/telnetd/sys_term.c
@@ -1287,6 +1287,16 @@ start_login(host, autologin, name)
#endif
#if defined (AUTHENTICATION)
if (auth_level >= 0 && autologin == AUTH_VALID) {
+ if (name[0] == '-') {
+ /* Authenticated and authorized to log in to an
+ account starting with '-'? Even if that
+ unlikely case comes to pass, the current login
+ program will not parse the resulting command
+ line properly. */
+ syslog(LOG_ERR, "user name cannot start with '-'");
+ fatal(net, "user name cannot start with '-'");
+ exit(1);
+ }
# if !defined(NO_LOGIN_F)
#if defined(LOGIN_CAP_F)
argv = addarg(argv, "-F");
@@ -1377,12 +1387,20 @@ start_login(host, autologin, name)
} else
#endif
if (getenv("USER")) {
- argv = addarg(argv, getenv("USER"));
+ char *user = getenv("USER");
+ if (user[0] == '-') {
+ /* "telnet -l-x ..." */
+ syslog(LOG_ERR, "user name cannot start with '-'");
+ fatal(net, "user name cannot start with '-'");
+ exit(EXIT_FAILURE);
+ }
+ argv = addarg(argv, user);
#if defined(LOGIN_ARGS) && defined(NO_LOGIN_P)
{
register char **cpp;
for (cpp = environ; *cpp; cpp++)
- argv = addarg(argv, *cpp);
+ if ((*cpp)[0] != '-')
+ argv = addarg(argv, *cpp);
}
#endif
/*
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