Syslinux - Jan 2004 - tftpd-hpa suggestions

Hello, Peter and others!

there are some issues regarding the tftp-hpa server:

1. Running as Windows service seems to require that the application does
   not detach (otherwise "net start" says smth. like "could not
start,
   the service didn't report any errors").

   The attached patch adds the option "-n", which can be used to have
   tftpd run in foreground.

2. By default, tftpd tries to drop privileges. Under Windows, this
   requires:

   * creation of user "nobody", not present by default;

   * granting special privileges to the user running the daemon (the
     default choice is "SYSTEM" if run as a service) -- namely,
running
     processes as another user without giving the password (smth.
     similar to SUID).

   This leads to the following problems:

   * I don't see much sense in granting powerful privileges in order to
     immediately drop them.

   * According to one of the leading cygwin developers, this would not
     work under Windows 2003 since the system drops these privileges
     automatically before starting the service
     (http://marc.theaimsgroup.com/?l=cygwin&m=107003209905031&w=2).

   That is why it was recommended to me to use the daemon without
   switching to nobody. In order to further minimize the risk, one can
   run the service as some special user, created specifically for that
   purpose.

   The attached patch #ifdefs the relevant code -- I didn't implement it
   as an option since I couldn't imagine a scenario where one could need
   it as an option.

3. The server seems to have at least one command line syntax example
   where the directory name is not required. I have changed the man page
   accordingly.

I suggest to include these changes in the distribution. What do you
think?

With kind regards,
Baurjan.

Hello,

I was asked to resend the patches, here they are.

With kind regards,
Baurjan.

--
CT SE 2
Siemens AG, Mch P


nodetach:

diff -NaurPX ./dontdiff.ibr tftp-hpa-0.35.orig/tftpd/tftpd.8.in
tftp-hpa-0.35/tftpd/tftpd.8.in
--- tftp-hpa-0.35.orig/tftpd/tftpd.8.in	2003-08-23 02:33:15.000000000 +0200
+++ tftp-hpa-0.35/tftpd/tftpd.8.in	2004-01-12 17:19:54.000000000 +0100
@@ -162,6 +162,10 @@
 .B \-V
 Print the version number and configuration to standard output, then
 exit gracefully.
+.TP
+.B \-n
+Do not detach the daemon. This option is necessary to run as Windows
+service, but can be also used for debugging purposes.
 .SH "RFC 2347 OPTION NEGOTIATION"
 This version of
 .B tftpd
diff -NaurPX ./dontdiff.ibr tftp-hpa-0.35.orig/tftpd/tftpd.c
tftp-hpa-0.35/tftpd/tftpd.c
--- tftp-hpa-0.35.orig/tftpd/tftpd.c	2004-01-08 21:48:30.000000000 +0100
+++ tftp-hpa-0.35/tftpd/tftpd.c	2004-01-12 17:34:40.000000000 +0100
@@ -107,6 +107,7 @@
 int	secure = 0;
 int	cancreate = 0;
 int	unixperms = 0;
+int	daemonize = 1;
 
 int verbosity = 0;
 
@@ -162,7 +163,7 @@
 static void
 usage(void)
 {
-  syslog(LOG_ERR, "Usage: %s [-vcl][-a address][-m mappings][-u user][-t
inetd_timeout][-T pkt_timeout][-r option...] [-s] [directory ...]",
+  syslog(LOG_ERR, "Usage: %s [-vcl][-a address][-m mappings][-n][-u
user][-t inetd_timeout][-T pkt_timeout][-r option...] [-s] [directory
...]",
 	 __progname);
   exit(EX_USAGE);
 }
@@ -281,7 +282,7 @@
   
   openlog(__progname, LOG_PID|LOG_NDELAY, LOG_DAEMON);
   
-  while ((c = getopt(argc, argv, "cspvVla:B:u:U:r:t:T:m:")) != -1)
+  while ((c = getopt(argc, argv, "cspvVnla:B:u:U:r:t:T:m:")) != -1)
     switch (c) {
     case 'c':
       cancreate = 1;
@@ -364,6 +365,9 @@
       printf("%s\n", TFTPD_CONFIG_STR);
       exit(0);
       break;
+    case 'n':
+      daemonize = 0;
+      break;
     default:
       usage();
       break;
@@ -463,14 +467,18 @@
 
     /* Daemonize this process */
     {
-      pid_t f = fork();
       int nfd;
-      if ( f > 0 )
-	exit(0);
-      if ( f < 0 ) {
-	syslog(LOG_ERR, "cannot fork: %m");
-	exit(EX_OSERR);
+
+      if (daemonize) {
+        pid_t f = fork();
+        if ( f > 0 )
+	  exit(0);
+        if ( f < 0 ) {
+	  syslog(LOG_ERR, "cannot fork: %m");
+	  exit(EX_OSERR);
+        }
       }
+
       nfd = open("/dev/null", O_RDWR);
       if ( nfd >= 3 ) {
 #ifdef HAVE_DUP2


nodrop:

diff -NaurPX ./dontdiff.ibr tftp-hpa-0.35-nodetach/tftpd/tftpd.c
tftp-hpa-0.35/tftpd/tftpd.c
--- tftp-hpa-0.35-nodetach/tftpd/tftpd.c	2004-01-12 17:34:40.000000000 +0100
+++ tftp-hpa-0.35/tftpd/tftpd.c	2004-01-13 11:28:32.000000000 +0100
@@ -254,7 +254,6 @@
 main(int argc, char **argv)
 {
   struct tftphdr *tp;
-  struct passwd *pw;
   struct options *opt;
   struct sockaddr_in myaddr;
   struct sockaddr_in bindaddr;
@@ -266,14 +265,17 @@
   mode_t my_umask = 0;
   int spec_umask = 0;
   int c;
-  int setrv;
   int waittime = 900;		/* Default time to wait for a connect*/
-  const char *user = "nobody";	/* Default user */
   char *p, *ep;
 #ifdef WITH_REGEX
   char *rewrite_file = NULL;
 #endif
   u_short tp_opcode;
+#ifndef __CYGWIN__
+  struct passwd *pw;
+  int setrv;
+  const char *user = "nobody";	/* Default user */
+#endif  /* __CYGWIN__ */
 
   /* basename() is way too much of a pain from a portability standpoint */
 
@@ -326,7 +328,11 @@
       }
       break;
     case 'u':
+#ifndef __CYGWIN__
       user = optarg;
+#else
+      syslog(LOG_WARNING, "\"-u\" option has no effect in the
Cygwin port.");
+#endif  /* __CYGWIN__ */
       break;
     case 'U':
       my_umask = strtoul(optarg, &ep, 8);
@@ -394,11 +400,13 @@
     }
   }
   
+#ifndef __CYGWIN__
   pw = getpwnam(user);
   if (!pw) {
     syslog(LOG_ERR, "no user %s: %m", user);
     exit(EX_NOUSER);
   }
+#endif  /* __CYGWIN__ */
 
   if ( spec_umask || !unixperms )
     umask(my_umask);
@@ -636,6 +644,7 @@
     exit(EX_IOERR);
   }
 
+#ifndef __CYGWIN__
   /* Set up the supplementary group access list if possible */
   /* /etc/group still need to be accessible at this point */
 #ifdef HAVE_INITGROUPS
@@ -651,6 +660,7 @@
   }
 #endif
 #endif
+#endif  /* __CYGWIN__ */
 
   /* Chroot and drop privileges */
   if (secure) {
@@ -663,6 +673,7 @@
 #endif
   }
 
+#ifndef __CYGWIN__
 #ifdef HAVE_SETREGID
   setrv = setregid(pw->pw_gid, pw->pw_gid);
 #else
@@ -681,6 +692,7 @@
     syslog(LOG_ERR, "cannot drop privileges: %m");
     exit(EX_OSERR);
   }
+#endif  /* __CYGWIN__ */
   
   /* Other basic setup */
   from.sin_family = AF_INET;


man:

diff -NaurPX ./dontdiff.ibr tftp-hpa-0.34-nodetach/tftpd/tftpd.8.in
tftp-hpa-0.34/tftpd/tftpd.8.in
--- tftp-hpa-0.34-nodetach/tftpd/tftpd.8.in	2003-12-10 11:22:32.000000000 +0100
+++ tftp-hpa-0.34/tftpd/tftpd.8.in	2003-12-10 14:05:21.000000000 +0100
@@ -38,7 +38,7 @@
 .SH SYNOPSIS
 .B in.tftpd
 .RI [ options... ]
-.I directory...
+.RI [ directory... ]
 .SH DESCRIPTION
 .B tftpd
 is a server for the IPv4 Trivial File Transfer Protocol.  The TFTP