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Allow tftpd to run as a specified user, not just `nobody'.

Browse Source 
Update documentation to reflect new option.  Also fix documentation
style and add missing references.

PR:		21268
Submitted by:	"Aleksandr A. Babaylov" <babolo@links.ru>
Reviewed by:	imp
This commit is contained in:
Garrett Wollman 2000-09-14 19:08:29 +00:00
parent c137d6780d
commit f62eaadff1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=65850
2 changed files with 55 additions and 28 deletions
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73
libexec/tftpd/tftpd.8
View File

@ -41,16 +41,16 @@
Internet Trivial File Transfer Protocol server
.Sh SYNOPSIS
.Nm /usr/libexec/tftpd
.Op Fl l
.Op Fl n
.Op Fl ln
.Op Fl s Ar directory
.Op Fl u Ar user
.Op Ar directory ...
.Sh DESCRIPTION
.Nm Tftpd
is a server which supports the
Internet Trivial File Transfer
Protocol (\c
.Tn RFC 783).
Protocol
.Pq Tn RFC 1350 .
The
.Tn TFTP
server operates
@ -90,25 +90,39 @@ names are prefixed by the one of the given directories.
The given directories are also treated as a search path for
relative filename requests.
.Pp
The chroot option provides additional security by restricting access
of
.Nm
to only a chroot'd file system. This is useful when moving
from an OS that supported
The
.Fl s
as a boot server. Because chroot is restricted to root, you must run
option provides additional security by changing
.Nm tftpd Ns No 's
root directory, thereby prohibiting accesses outside of the specified
.Ar directory .
Because
.Xr chroot 2
requires super-user privileges,
.Nm
as root. However, if you chroot, then
must be run as root.
However, after performing the
.Fn chroot ,
.Nm
will set its user id to nobody.
will set its user id to that of the specified
.Ar user ,
or
.Dq nobody
if no
.Fl u
option is specified.
.Pp
The options are:
.Bl -tag -width Ds
.It Fl l
Log all requests using
.Xr syslog 3
with the facility of LOG_FTP. Note: Logging of LOG_FTP messages
will also need to be enabled in the syslog configuration file
with the facility of
.Dv LOG_FTP .
Note: Logging of
.Dv LOG_FTP
messages
must also be enabled in the syslog configuration file,
.Xr syslog.conf 5 .
.It Fl n
Suppress negative acknowledgement of requests for nonexistent
@ -116,23 +130,32 @@ relative filenames.
.It Fl s Ar directory
Cause
.Nm
to chroot to
.Pa directory
before accepting commands. In addition, the user id is set to
nobody.
.Pp
If you are not running
.Fl s ,
no user id change will be
attempted. You should not run
to change its root directory to
.Pa directory .
After changing roots but before accepting commands,
.Nm
as root unless you are using
.Fl s .
will switch credentials to an unprivileged user.
.It Fl u Ar user
Switch credentials to
.Ar user
(default
.Dq nobody )
when the
.Fl s
option is used.
The user must be specified by name, not a numeric UID.
.El
.Sh SEE ALSO
.Xr tftp 1 ,
.Xr chroot 2 ,
.Xr inetd 8 ,
.Xr syslogd 8
.Rs
.%A K. R. Sollins
.%T The TFTP Protocol (Revision 2)
.%D July 1992
.%O RFC 1350, STD 33
.Re
.Sh HISTORY
The
.Nm

10
libexec/tftpd/tftpd.c
View File

@ -121,9 +121,10 @@ main(argc, argv)
struct sockaddr_in sin;
char *chroot_dir = NULL;
struct passwd *nobody;
char *chuser = "nobody";
openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
while ((ch = getopt(argc, argv, "lns:")) != -1) {
while ((ch = getopt(argc, argv, "lns:u:")) != -1) {
switch (ch) {
case 'l':
logging = 1;
@ -134,6 +135,9 @@ main(argc, argv)
case 's':
chroot_dir = optarg;
break;
case 'u':
chuser = optarg;
break;
default:
syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
}
@ -226,8 +230,8 @@ main(argc, argv)
*/
if (chroot_dir) {
/* Must get this before chroot because /etc might go away */
if ((nobody = getpwnam("nobody")) == NULL) {
syslog(LOG_ERR, "nobody: no such user");
if ((nobody = getpwnam(chuser)) == NULL) {
syslog(LOG_ERR, "%s: no such user", chuser);
exit(1);
}
if (chroot(chroot_dir)) {