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/*
* Copyright (c) 2010, Oracle America, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
* * Neither the name of the "Oracle America, Inc." nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <libc-lock.h>
#define STARTPORT 600
#define LOWPORT 512
#define ENDPORT (IPPORT_RESERVED - 1)
#define NPORTS (ENDPORT - STARTPORT + 1)
/*
* Read the file /etc/rpc.blacklisted, so that we don't bind
* to this ports.
*/
static int blacklist_read;
static int *list;
static int list_size = 0;
static void
load_blacklist (void)
{
FILE *fp;
char *buf = NULL;
size_t buflen = 0;
int size = 0, ptr = 0;
blacklist_read = 1;
fp = fopen ("/etc/bindresvport.blacklist", "r");
if (NULL == fp)
return;
while (!feof_unlocked (fp))
{
unsigned long port;
char *tmp, *cp;
ssize_t n = __getline (&buf, &buflen, fp);
if (n < 1)
break;
cp = buf;
tmp = strchr (cp, '#'); /* remove comments */
if (tmp)
*tmp = '\0';
while (isspace ((int)*cp)) /* remove spaces and tabs */
++cp;
if (*cp == '\0') /* ignore empty lines */
continue;
if (cp[strlen (cp) - 1] == '\n')
cp[strlen (cp) - 1] = '\0';
port = strtoul (cp, &tmp, 0);
while (isspace(*tmp))
++tmp;
if (*tmp != '\0' || (port == ULONG_MAX && errno == ERANGE))
continue;
/* Don't bother with out-of-range ports */
if (port < LOWPORT || port > ENDPORT)
continue;
if (ptr >= size)
{
size += 10;
list = realloc (list, size * sizeof (int));
if (list == NULL)
{
free (buf);
return;
}
}
list[ptr++] = port;
}
fclose (fp);
if (buf)
free (buf);
list_size = ptr;
}
/*
* Locks the static variables in this file.
*/
__libc_lock_define_initialized (static, lock);
/*
* Bind a socket to a privileged IP port
*/
int
bindresvport (int sd, struct sockaddr_in *sin)
{
static short startport = STARTPORT;
static short port;
struct sockaddr_in myaddr;
int i;
if (!blacklist_read)
load_blacklist ();
if (sin == (struct sockaddr_in *) 0)
{
sin = &myaddr;
__bzero (sin, sizeof (*sin));
sin->sin_family = AF_INET;
}
else if (sin->sin_family != AF_INET)
{
__set_errno (EAFNOSUPPORT);
return -1;
}
if (port == 0)
{
port = (__getpid () % NPORTS) + STARTPORT;
}
__set_errno (EADDRINUSE);
/* Initialize to make gcc happy. */
int res = -1;
int nports = ENDPORT - startport + 1;
int endport = ENDPORT;
__libc_lock_lock (lock);
again:
for (i = 0; i < nports; ++i)
{
int j;
sin->sin_port = htons (port);
/* Check, if this port is not blacklisted. */
for (j = 0; j < list_size; j++)
if (port == list[j])
goto try_next_port;
res = __bind (sd, sin, sizeof (struct sockaddr_in));
if (res >= 0 || errno != EADDRINUSE)
break;
try_next_port:
if (++port > endport)
port = startport;
}
if (i == nports && startport != LOWPORT)
{
startport = LOWPORT;
endport = STARTPORT - 1;
nports = STARTPORT - LOWPORT;
port = LOWPORT + port % (STARTPORT - LOWPORT);
goto again;
}
__libc_lock_unlock (lock);
return res;
}
libc_hidden_def (bindresvport)
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