Imported from /home/lorry/working-area/delta_tcp-wrappers/tcp_wrappers_7.6.tar.gz.HEADtcp_wrappers_7.6master

1 files changed, 308 insertions, 0 deletions

diff --git a/workarounds.c b/workarounds.c
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+ /*
+  * 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.
+  */
+
+#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>
+
+extern int errno;
+
+#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(string)
+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(buf, len, fp)
+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(sock, buf, buflen, flags, from, fromlen)
+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(sock, sa, len)
+int     sock;
+struct sockaddr *sa;
+int    *len;
+{
+    int     ret;
+    struct sockaddr_in *sin = (struct sockaddr_in *) sa;
+
+    if ((ret = getpeername(sock, sa, len)) >= 0
+	&& sa->sa_family == AF_INET
+	&& sin->sin_addr.s_addr == 0) {
+	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(ptr)
+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(name)
+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(buf, sep)
+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(buf, sep)
+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 */