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/*
* Ident-2 - an Identity server for UNIX
* Copyright (C) 1998-2001 Michael Bacarella
* Copyright (C) 2003 Netgraft Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Please view the file README for program information.
*/
/*
* Support for Linux machine dependancies
*/
#include "ident2.h"
#define PID_FILE "/var/run/ident2.pid"
/**
** drop to the lowest permission level
** possible. 'nobody' is ideal for linux
**/
int
m_reduce_rights (void)
{
struct passwd *pw;
if ((geteuid() && getuid())
|| Dont_Change_Uid == TRUE)
return 0;
if ((pw = getpwnam ("nobody")) == NULL) {
syslog (LOG_ERR, "error: getpwnam(nobody): %s",
strerror (errno));
return -1;
}
if (setuid (pw->pw_uid) == -1) {
syslog (LOG_ERR, "error: setuid(%d): %s",
pw->pw_uid, strerror (errno));
return -1;
}
return 0;
}
/**
** find what user belongs to the connection
** described by LPORT, RPORT, RADDR, and LADDR.
** return the uid.
**/
int
m_get_uid (struct in_addr *laddr, u_short lp,
struct in_addr *raddr, u_short rp)
{
FILE *fp;
char buf[150];
if ((fp = fopen ("/proc/net/tcp", "r")) == NULL) {
syslog (LOG_ERR, "error reading /proc/net/tcp: %s",
strerror (errno));
return -1;
}
fgets (buf, 149, fp); /* eat header!)*$ */
while (fgets (buf, 149, fp)) {
unsigned long local_addr, remote_addr;
unsigned long tx_queue, rx_queue, tm_when;
int sl, uid, retrnsmt, st, tr, local_port, remote_port;
if (sscanf (buf, "%d: %lX:%x %lX:%x %x %lX:%lX %x:%lX %x %d",
&sl, &local_addr, &local_port, &remote_addr,
&remote_port, &st, &tx_queue, &rx_queue,
&tr, &tm_when, &retrnsmt, &uid) == 12) {
if (lp == local_port && rp == remote_port
&& remote_addr == raddr->s_addr) {
if (laddr == NULL) {
fclose (fp);
return uid;
}
else if (laddr->s_addr
== local_addr) {
fclose (fp);
return uid;
}
}
}
}
fclose (fp);
return -1;
}
/*
* records the pid for service management purposes.
* example: under Red Hat,Debian,etc pid is written to
* /var/run/identd.pid
* PID support suggested (and previously implemented)
* by Alexander Reelsen.
*/
int
m_register_pid (void)
{
#ifdef HAS_VAR_RUN
FILE *fp;
if ((fp = fopen (PID_FILE, "w")) == NULL) {
syslog (LOG_WARNING, "couldn't record pid in %s: %s -- "
"automatic shutdown with system not available",
PID_FILE, strerror (errno));
return -1;
}
fprintf (fp, "%u\n", getpid ());
fclose (fp);
#endif
return 0;
}
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