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Last update: Nov 27 1994 for logdaemon release 4.5. A change log can be found at the end of this document. Introduction: ============= This archive contains the result of years of gradual transformations on BSD source. The code works with SunOS 4, SunOS 5 (Solaris), Ultrix 4.x and other BSD/SYSV4 clones. Some code may also work with HP-UX 9.0. (1) rsh and rlogin daemons that log the remote username and perform logging and access control in tcp/ip wrapper style. By default these daemons do not accept wildcards in hosts.equiv or .rhosts files. Both daemons have an '-l' option to disable user .rhosts files. (2) ftpd, rexecd and login software with fascist login failure logging and with optional support for S/Key one-time passwords. The rexecd daemon disallows root logins, once my favourite backdoor. The support for S/Key one-time passwords is optional, and completely invisible to users that do not need it. UNIX passwords are still permitted by default. A short description of how to use S/Key can be found in the skey subdirectory. Binaries for DOS and other systems can be found on thumper.bellcore.com. (3) an S/Key login shell for sites that cannot replace the login program. Users first log into a password-less dummy account. The S/Key login shell prompts for their real account name and presents the corresponding S/Key challenge. The S/Key support uses the MD4 or MD5 hash function. The mode (MD4 by default, for backwards compatibility) is selected in skey/Makefile. The rshd and rlogind programs need the libwrap.a library that comes with recent (version >= 7.0) tcp/ip daemon wrapper implementations. In order to build rshd and rlogind you will have to do a setenv LOG_TCP /directory/with/libwrap.a Contents per directory: ======================= rlogind logging and access control in tcp wrapper style. Regular access is logged (by default) with priority daemon.info. Rejected access is logged with daemon.warn or more urgent. SunOS 4.x, SunOS 5.x and Ultrix 4.x. In order to use the "-l" (ignore user .rhosts files) option you will also need to install the login clone (see below). May work with HP-UX 9.0 rshd logging and access control in tcp wrapper style. Regular access is logged (by default) with priority daemon.info. Rejected access is logged with daemon.warn or more urgent. SunOS 4.x, SunOS 5.x and Ultrix 4.x. May work with HP-UX 9.0 login hacked for SunOS 4.x, SunOS 5.x, with optional access control per (user,host) or per (user, tty); fbtab(5) security; fascist login failure logging. Regular logins are logged with priority auth.info, unusual or rejected logins with auth.notice. S/Key support. Can also be used with Ultrix 4.x for logins on non-graphics consoles. Appears to work with HP-UX 9.0. rexecd Regular access is logged with priority daemon.info. Fascist login failure logging. Rejected access is logged with auth.warn or more urgent. Access to the root account is prohibited. S/Key support. Tested with SunOS 4.x, SunOS 5.x. Should also work with Ultrix. May work with HP-UX 9.0 ftpd ftp daemon with fascist logging and login failure detection much like the login clone. Also logs anonymous ftp transfers. Tested with SunOS [45]. S/Key support. Should also work with Ultrix 4.x. May work with HP-UX 9.0 telnetd pretty dumb BSD 4.3 telnetd. No access control or logging, but compatible with SunOS 4.x, Ultrix 4.x, SunOS 5.x. May work with HP-UX 9.0. keysu NET/2 BSD su command ported back to SunOS 4.x, with S/Key support. Tested with FreeBSD and SunOS 4.1.3. May work with HP-UX 9.0. skeysh An S/key login shell for sites that cannot replace the login program. The solution is to create a dummy account with skeysh as the login shell. skeysh is nothing but a stripped-down skey-only login program. People first log into the dummy account. This drops them into skeysh that prompts them for their real account name and presents the corresponding S/Key challenge. Tested with SunOS 4.1.3 and with Solaris 2.3. Should work anywhere the login clone works. lib additional routines used by login and by some daemons. Includes the ruserok() function that understands NIS, NFS (yuck) and that optionally skips user .rhosts files. skey Portions of S/Key source from thumper.bellcore.com, plus that I hacked together myself. All bugs are my own. Edit the Makefile to choose between the MD4 or MD5 secure hash function. MD4 is default, for backwards compatibility. The README* files in the respective subdirectories give more details. Please report any problems to: Wietse Venema (wietse@wzv.win.tue.nl) Eindhoven University of Technology Eindhoven, The Netherlands Change log: =========== 901218 Fixed a problem with NOFLSH in login.c that caused interrupts to not flush the terminal input queue. 910209 Added per-user login access control. 911128 Added support to login for SunOS 4.x style /etc/fbtab, a table of devices whose protection and ownership is to be adjusted when a user logs in. 920609 Added tcp wrapper (log_tcp) style access control to rlogind and rshd. Improved the remote host name verification code. Added the LD_xxx environment fix to login. 920624 Login no longer just dies when the connection is broken, but first reports a login failure. This exposes an old cracker's trick. 921029 Ported to Ultrix 4.2. Most of the work was finding out why the login process did not have a controlling terminal. 921208 Ported to Solaris 2.0. rlogind can now work with the /bin/login that comes with most UNIXes. This was desirable because not everyone is in a position to replace /bin/login. Moreover, some SYSV logins can't even support the '-f' option at all (or everyone could login without a password). 2alpha version released. 921229 Tested with Solaris 2.1; some cleanups after looking at modified 4.4BSD sources from Charles Hedrick (hedrick@cs.rutgers.edu). The sources can be found on farside.rutgers.edu. 930103 Most of the sensible SYSV login features implemented. Frozen after check, check and double check. The source really suffered from porting and has become too ugly. It becomes a lot more readable after running through the unifdef program. Version 2beta released. 930119 Version 2 released after compatibility patches: rshd path; disabling the local domain stripping in login.c; cleanup utmpx file after rejecting an rlogin connection. 930221 Added group support to the login access control code, so that we can disallow off-site logins to wheel group members. Group matches work only for accounts that are explicitly listed in the group file: the matching is not based on group id values. 930222 Stole the code for the EXCEPT operator from the tcp wrapper. This, and the previous change, allows me to replace: # Disallow non-local logins into the wheel accounts +:foo bar baz:LOCAL .my.domain -:foo bar baz:ALL into the much easier to understand: -:wheel:ALL EXCEPT LOCAL .my.domain Assuming, of course, that the default is to permit access. 930331 Added per-program hints on how to configure syslogd. Added __svr4__ to the Solaris CFLAGS macro because the unbundled C compiler does not define it. 930925 Upped the number of ptys that telnetd and rlogind will attempt to open. The original versions would give up after 64 ptys. 930925 rshd now preserves TZ info when running under SunOS 5. We were too compatible with SunOS 5. 930925 login will now syslog() all regular logins, too. It took me too much time to examine individual wtmp files. 930929 Ultrix last minute patch to fix rshd environment handling. The fix must be ok for SunOS too but no time to verify this. 931206 With SunOS 5.x, Do not pass the "-p" option to login. 931212 Added logindevperm support for compatibility with SunOS 5.3. 931212 Added support to the login command for secure (DES) RPC (only for SunOS [45].x). This requires that the cleartext password be kept around until we have dropped privileges. Had to jump some hoops to prevent the program from ever dropping core with a cleartext password. 931212 Print error message when the login.access file exists but cannot be opened. 931225 Added S/Key support to login 'cause I was going on a trip. 931229 While on my trip, added S/Key support to ftpd. 940106 Woke up at 5am and realized there was a problem in my S/Key stuff. 940107 S/Key Solaris portability fixes from Douglas Lee Schales. 940110 Make sure that keyinit does not produce world-writable files. 940112 SysV4.0 wtmpx portability fixes from Baruch Cochavy. 940124 Fixed some ftpd and skey things that broke for Ultrix 4.x. 940125 Fix for Solaris uname(2) >0 return value. I fixed this before but somehow the change got misplaced. From Douglas Lee Schales. 940130 Made initial seed from skeyinit.c more random (use seconds instead of minutes). I managed to produce the same seed on multiple machines. The whole seed generation procedure sucks anyway: taking the first two letters of a host name. 940205 Made initial seed from skeyinit.c more random (use last 5 digits of current time in seconds). 940206 Fixed some login Makefile things that broke for Ultrix 4.x. 940206 Had some real fun with (argh) NIS+. The old BSD login code would blindly close all filedescriptors > 2 right AFTER it had processed the command-line options. I had to move the closing of open files right to the top of the main program. The reason for this is that all kinds of nisplus library routines secretly open sockets or files and keep them open forever. They get very upset when you unexpectedly close their open files. 940306 Finally got so disgusted from the BSD/SYSV #ifdefs that I began to clean up the login program. From now on we use POSIX instead of BSD/SYSV ifdefs. Many of my personal enhancements are no longer conditional. Ultrix misses some definitions so login won't compile there anymore. Kerberos code for login.c (John DiMarco <jdd@cdf.toronto.edu>). 940312 Security feature: when S/Key decides whether UNIX passwords are ok, skip IP addresses listed for the remote host that appear to belong to someone else. Cleaned up the rlogind/telnetd code (POSIX interfaces instead of BSD/SYSV ifdefs). Changed the ftpd S/Key password prompt so that the MS-DOS `termkey' TSR can parse it. 940314 Cleaned up the ftpd code (POSIX interfaces instead of BSD/SYSV ifdefs). Ultrix misses some definitions so ftpd won't compile there anymore. All code now compiles and works on freebsd, which has become my development platform while traveling. The code compiles OK on an Indy running IRIX 5.something: just pretend to be sunos5. 940317 The telnetd/login programs no longer assume 7 or 8 bits, but leave CS7/CS8 tty settings alone. 940321 Modern rloginds seem to prefer 8-bit clean settings, so we force CS8 from now on. 940326 Our system administrator wanted netgroup support in the login access control file. This took only a few lines of code. A netgroup is written as @name, and can be used in host patterns and in user patterns. Included the keyinfo command and documentation, after getting rid of localisms. keyinit now restores the tty settings when it is interrupted. logdaemon-4.1.tar.Z released. 940426 Backwards compatibility code for Ultrix in login and ftpd. Added keysu (s/key su) command. This has little to do with daemon stuff but it just makes the package complete. This has been tested only with SunOS 4.x and FreeBSD. Unset FLUSHO in login.c, in case it helps. 940430 rexecd and rlogind now use the fd_set macros, to shut up the ANSI C compiler. converted net/2 su.1 man page to old -man macro style. William C. DenBesten asked for user@host patterns in the login access control files, so he could control many machines with just one set of rules. Fortunately, this took only a few lines of code. The hostpart is matched against the local host name. With user@host patterns and netgroups you can build impressive patterns such as @usergroup@@hostgroup. 940505 Peter Kossakowski (dfn cert) mentioned he usefulness of the -l option to ignore user .rhosts files. On most systems, the ruserok() library function have no support for that, so a modified version is provided. As a bonus, '+' wildcards are by default no longer accepted. Instead a loud complaint is sent to the syslogd. The programs must be compiled without -DNOPLUS to re-enable '+' wildcards. The -l option is supported by rshd, rlogind and by the login program (rlogind must pass on the -l option when the login program does the hosts.equiv/rhosts processing). Thus, in order to use -l you will have to replace both rlogind and login (and, of course, rshd). Most path names and syslog logging classes are now configurable from the Makefile. 940516 Fixed the README and released version 4.2. 940523 Just like the login, the ftpd now tries to avoid dumping core with cleartext or encrypted (shadow) passwords. 940628 Generalized the format of the /etc/skey.access file so you can permit/deny UNIX passwords depending on user, tty and/or host. There is a new manual page, skey/skey.access.5 that documents this new format. 940718 Fixed another thing that broke with Ultrix: in lib/rcmd.c moved an #endif up to above the rresvport() routine. Now that you can specify what terminals are secure, the S/Key code has been modified to always permit UNIX passwords on the console. This saves you the embarrasment of having to break into your own machine. Alas, on some systems the console is not called /dev/console. Released version 4.3. 940908 Added -user and -host support to ruserok(). No-one complained sofar, but most systems document it. Looks like one feature that Berkeley dropped. HP-UX and BSDI support from Howard Chu for login, keysu and s/key. Replaced Howard's "vendor" #ifdefs by "feature" #ifdefs. (s/key) When built with -DSECURETTY, the keysu command will not accept the root password unless it is invoked from a secure terminal. Idea from Howard Chu. (s/key) "keyinit -s" would ask for counts up to 10000 but the actual limit is 9999 (Howard Chu). (s/key) Eliminated a possible localhost vs localhost.domain clash (Howard Chu). 940910 Collected system dependencies in one central file (sys_defs.h) and cleaned up the Makefiles. This may help when porting to other systems. 940911 After discussions with Guido van Rooij, documented several host name and address spoofing loopholes that may cause S/Key to permit UNIX passwords to unauthorized clients. 940914/5 Porting rexecd, ftpd, rlogind and telnetd to HP-UX 9.0 was not impossibly difficult. The effort may be useful to someone. 940917 Disabled the `site' extensions (umask, chmod) for ftp guest logins. 940922 Replaced the MD4 code by the byte-order independent versions from the NRL distribution on thumper.bellcore.com. MD4 is still the default. Edit skey/Makefile to switch to MD5. 941001 Idea from *Hobbit*: sites that cannot replace their login program create a dummy s/key account with as login shell a very much stripped-down skey-only login program. The skeysh program is my result of such an exercise. 941002 Cleaned up docs and comments. Released version 4.4. 941014 setenv() was missing an argument in skeysh/skeysh.c. This should not cause problems, but gcc barfs on it. sigh. 941022 Fixed pointer indirection level in lib/utmp_login.c. This would produce unpredictable results for HP-UX. 941105 Parametrized some hard-coded lengths for environment variables and fixed some rather short limits on username length. 941121 Changed the default console from /dev/console to none. This is more compatible with SysV (Kevin Davidson). 941121 Dropped ptyopen() etc. support for HP-UX. Having to support BSD and SYSV ptys is bad enough. 941126 It seems that assignments of static data to the environ variable may cause trouble on non-BSD systems. Instead of environ = envinit; execl(...); we no longer replace environ but truncate it and use putenv(): environ[0] = 0; putenv(...); 941127 On System V all daemons now preserve the complete initial environment. There were several reports of missing TZ values. I was unable to reproduce them with Solaris 2.3 and gcc. 941127 Fixed skey/skeylogin.c to look at more than just the first 8 characters of the login name. 941127 Fixed something in the skeysh/Makefile that broke on Ultrix. Released version 4.5. 941129 With Solaris 2.x, keysu would recognize '-' as a user name. This is due to getopt() incompatibilities. Fix: SysV su does not support options anyway, so drop the getopt loop. Reported by in1052@wlv.ac.uk (A.Parkes). 941129 Found another static assignment to environ in keysu.c. 941130 Should have used setenv() to set the user's path in keysu. Reported by Patrick Cipiere <Patrick.Cipiere@sophia.inria.fr>. 941209 With passive open, do not wait forever in accept(). Idea from casper@fwi.uva.nl in article <3asnqc$1h0@mail.fwi.uva.nl>. 941218 Changed rlogind and rshd to use the open-ended tcp wrapper 7.0 programmatic interface, so that banners can be used. 950101 Patches from David Mazieres: close redundant file descriptors in rshd and rexecd; workaround for broken HPUX setsid(); also, the HP-UX baud-rate codes differ from those on other platforms. 950101 Ftpd would send bare linefeeds when listing files over an ASCII-mode data connection, causing problems with wattcp clients (reported by Shou-Chuan Lai). 950108 Released 4.6, together with TCP wrappers 7.0. 950111 David Mazieres: HPUX cc is pickier than I expected. What's worse, they already define a struct request_info. Time for a horrible workaround. 950111 In S/Key passwords, accept commas instead of blanks, to work around stupid software that collapses blanks in passwords. 950121 Added SYSV shadow support to keysu (suggestion: Leif Hedstrom). 950213 skeyaccess could dereference a null pointer when host lookup failed (Larry J. Blunk @ Merit.edu). How embarrassing. 950222 Make ftpd try again when the data port bind() fails with EADDRINUSE. 950222 keysu did not strip the "/dev/" from the device name when looking for a secure terminal (Rob Liebschutz). Released 4.7.