/*
* Workarounds for known system software bugs. This module provides wrappers
* around library functions and system calls that are known to have problems
* on some systems. Most of these workarounds won't do any harm on regular
* systems.
*
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
*
* $FreeBSD$
*/
#ifndef lint
char sccsid[] = "@(#) workarounds.c 1.6 96/03/19 16:22:25";
#endif
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <stdio.h>
#include <syslog.h>
#include <string.h>
#ifdef USE_GETDOMAIN
#include <unistd.h>
#endif
#include "tcpd.h"
/*
* Some AIX versions advertise a too small MAXHOSTNAMELEN value (32).
* Result: long hostnames would be truncated, and connections would be
* dropped because of host name verification failures. Adrian van Bloois
* (A.vanBloois@info.nic.surfnet.nl) figured out what was the problem.
*/
#if (MAXHOSTNAMELEN < 64)
#undef MAXHOSTNAMELEN
#endif
/* In case not defined in <sys/param.h>. */
#ifndef MAXHOSTNAMELEN
#define MAXHOSTNAMELEN 256 /* storage for host name */
#endif
/*
* Some DG/UX inet_addr() versions return a struct/union instead of a long.
* You have this problem when the compiler complains about illegal lvalues
* or something like that. The following code fixes this mutant behaviour.
* It should not be enabled on "normal" systems.
*
* Bug reported by ben@piglet.cr.usgs.gov (Rev. Ben A. Mesander).
*/
#ifdef INET_ADDR_BUG
#undef inet_addr
long fix_inet_addr(char *string)
{
return (inet_addr(string).s_addr);
}
#endif /* INET_ADDR_BUG */
/*
* With some System-V versions, the fgets() library function does not
* account for partial reads from e.g. sockets. The result is that fgets()
* gives up too soon, causing username lookups to fail. Problem first
* reported for IRIX 4.0.5, by Steve Kotsopoulos <steve@ecf.toronto.edu>.
* The following code works around the problem. It does no harm on "normal"
* systems.
*/
#ifdef BROKEN_FGETS
#undef fgets
char *fix_fgets(char *buf, int len, FILE *fp)
{
char *cp = buf;
int c;
/*
* Copy until the buffer fills up, until EOF, or until a newline is
* found.
*/
while (len > 1 && (c = getc(fp)) != EOF) {
len--;
*cp++ = c;
if (c == '\n')
break;
}
/*
* Return 0 if nothing was read. This is correct even when a silly buffer
* length was specified.
*/
if (cp > buf) {
*cp = 0;
return (buf);
} else {
return (0);
}
}
#endif /* BROKEN_FGETS */
/*
* With early SunOS 5 versions, recvfrom() does not completely fill in the
* source address structure when doing a non-destructive read. The following
* code works around the problem. It does no harm on "normal" systems.
*/
#ifdef RECVFROM_BUG
#undef recvfrom
int fix_recvfrom(int sock, char *buf, int buflen, int flags,
struct sockaddr *from, int *fromlen)
{
int ret;
/* Assume that both ends of a socket belong to the same address family. */
if ((ret = recvfrom(sock, buf, buflen, flags, from, fromlen)) >= 0) {
if (from->sa_family == 0) {
struct sockaddr my_addr;
int my_addr_len = sizeof(my_addr);
if (getsockname(0, &my_addr, &my_addr_len)) {
tcpd_warn("getsockname: %m");
} else {
from->sa_family = my_addr.sa_family;
}
}
}
return (ret);
}
#endif /* RECVFROM_BUG */
/*
* The Apollo SR10.3 and some SYSV4 getpeername(2) versions do not return an
* error in case of a datagram-oriented socket. Instead, they claim that all
* UDP requests come from address 0.0.0.0. The following code works around
* the problem. It does no harm on "normal" systems.
*/
#ifdef GETPEERNAME_BUG
#undef getpeername
int fix_getpeername(int sock, struct sockaddr *sa, int *len)
{
int ret;
#ifdef INET6
struct sockaddr *sin = sa;
#else
struct sockaddr_in *sin = (struct sockaddr_in *) sa;
#endif
if ((ret = getpeername(sock, sa, len)) >= 0
#ifdef INET6
&& ((sin->su_si.si_family == AF_INET6
&& IN6_IS_ADDR_UNSPECIFIED(&sin->su_sin6.sin6_addr))
|| (sin->su_si.si_family == AF_INET
&& sin->su_sin.sin_addr.s_addr == 0))) {
#else
&& sa->sa_family == AF_INET
&& sin->sin_addr.s_addr == 0) {
#endif
errno = ENOTCONN;
return (-1);
} else {
return (ret);
}
}
#endif /* GETPEERNAME_BUG */
/*
* According to Karl Vogel (vogelke@c-17igp.wpafb.af.mil) some Pyramid
* versions have no yp_default_domain() function. We use getdomainname()
* instead.
*/
#ifdef USE_GETDOMAIN
int yp_get_default_domain(char **ptr)
{
static char mydomain[MAXHOSTNAMELEN];
*ptr = mydomain;
return (getdomainname(mydomain, MAXHOSTNAMELEN));
}
#endif /* USE_GETDOMAIN */
#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif
/*
* Solaris 2.4 gethostbyname() has problems with multihomed hosts. When
* doing DNS through NIS, only one host address ends up in the address list.
* All other addresses end up in the hostname alias list, interspersed with
* copies of the official host name. This would wreak havoc with tcpd's
* hostname double checks. Below is a workaround that should do no harm when
* accidentally left in. A side effect of the workaround is that address
* list members are no longer properly aligned for structure access.
*/
#ifdef SOLARIS_24_GETHOSTBYNAME_BUG
#undef gethostbyname
struct hostent *fix_gethostbyname(char *name)
{
struct hostent *hp;
struct in_addr addr;
char **o_addr_list;
char **o_aliases;
char **n_addr_list;
int broken_gethostbyname = 0;
if ((hp = gethostbyname(name)) && !hp->h_addr_list[1] && hp->h_aliases[1]) {
for (o_aliases = n_addr_list = hp->h_aliases; *o_aliases; o_aliases++) {
if ((addr.s_addr = inet_addr(*o_aliases)) != INADDR_NONE) {
memcpy(*n_addr_list++, (char *) &addr, hp->h_length);
broken_gethostbyname = 1;
}
}
if (broken_gethostbyname) {
o_addr_list = hp->h_addr_list;
memcpy(*n_addr_list++, *o_addr_list, hp->h_length);
*n_addr_list = 0;
hp->h_addr_list = hp->h_aliases;
hp->h_aliases = o_addr_list + 1;
}
}
return (hp);
}
#endif /* SOLARIS_24_GETHOSTBYNAME_BUG */
/*
* Horror! Some FreeBSD 2.0 libc routines call strtok(). Since tcpd depends
* heavily on strtok(), strange things may happen. Workaround: use our
* private strtok(). This has been fixed in the meantime.
*/
#ifdef USE_STRSEP
char *fix_strtok(char *buf, char *sep)
{
static char *state;
char *result;
if (buf)
state = buf;
while ((result = strsep(&state, sep)) && result[0] == 0)
/* void */ ;
return (result);
}
#endif /* USE_STRSEP */
/*
* IRIX 5.3 (and possibly earlier versions, too) library routines call the
* non-reentrant strtok() library routine, causing hosts to slip through
* allow/deny filters. Workaround: don't rely on the vendor and use our own
* strtok() function. FreeBSD 2.0 has a similar problem (fixed in 2.0.5).
*/
#ifdef LIBC_CALLS_STRTOK
char *my_strtok(char *buf, char *sep)
{
static char *state;
char *result;
if (buf)
state = buf;
/*
* Skip over separator characters and detect end of string.
*/
if (*(state += strspn(state, sep)) == 0)
return (0);
/*
* Skip over non-separator characters and terminate result.
*/
result = state;
if (*(state += strcspn(state, sep)) != 0)
*state++ = 0;
return (result);
}
#endif /* LIBC_CALLS_STRTOK */
