+/* This is copied from portmap 4.0-29 in RedHat. */
+
+ /*
+ * pmap_check - additional portmap security.
+ *
+ * Always reject non-local requests to update the portmapper tables.
+ *
+ * Refuse to forward mount requests to the nfs mount daemon. Otherwise, the
+ * requests would appear to come from the local system, and nfs export
+ * restrictions could be bypassed.
+ *
+ * Refuse to forward requests to the nfsd process.
+ *
+ * Refuse to forward requests to NIS (YP) daemons; The only exception is the
+ * YPPROC_DOMAIN_NONACK broadcast rpc call that is used to establish initial
+ * contact with the NIS server.
+ *
+ * Always allocate an unprivileged port when forwarding a request.
+ *
+ * If compiled with -DCHECK_PORT, require that requests to register or
+ * unregister a privileged port come from a privileged port. This makes it
+ * more difficult to replace a critical service by a trojan.
+ *
+ * If compiled with -DHOSTS_ACCESS, reject requests from hosts that are not
+ * authorized by the /etc/hosts.{allow,deny} files. The local system is
+ * always treated as an authorized host. The access control tables are never
+ * consulted for requests from the local system, and are always consulted
+ * for requests from other hosts. Access control is based on IP addresses
+ * only; attempts to map an address to a host name might cause the
+ * portmapper to hang.
+ *
+ * Author: Wietse Venema (wietse@wzv.win.tue.nl), dept. of Mathematics and
+ * Computing Science, Eindhoven University of Technology, The Netherlands.
+ */
+
+#include "tcpwrapper.h"
+
+#include <unistd.h>
+#include <string.h>
+#include <rpc/rpc.h>
+#include <rpc/pmap_prot.h>
+#include <syslog.h>
+#include <netdb.h>
+#include <pwd.h>
+#include <sys/types.h>
+#include <sys/signal.h>
+#ifdef SYSV40
+#include <netinet/in.h>
+#include <rpc/rpcent.h>
+#endif
+
+static void logit();
+static void toggle_verboselog();
+int verboselog = 0;
+int allow_severity = LOG_INFO;
+int deny_severity = LOG_WARNING;
+
+/* A handful of macros for "readability". */
+
+/* coming from libwrap.a (tcp_wrappers) */
+extern int hosts_ctl(char *daemon, char *name, char *addr, char *user);
+
+#define legal_port(a,p) \
+ (ntohs((a)->sin_port) < IPPORT_RESERVED || (p) >= IPPORT_RESERVED)
+
+#define log_bad_port(addr, proc, prog) \
+ logit(deny_severity, addr, proc, prog, ": request from unprivileged port")
+
+#define log_bad_host(addr, proc, prog) \
+ logit(deny_severity, addr, proc, prog, ": request from unauthorized host")
+
+#define log_bad_owner(addr, proc, prog) \
+ logit(deny_severity, addr, proc, prog, ": request from non-local host")
+
+#define log_no_forward(addr, proc, prog) \
+ logit(deny_severity, addr, proc, prog, ": request not forwarded")
+
+#define log_client(addr, proc, prog) \
+ logit(allow_severity, addr, proc, prog, "")
+
+int
+good_client(daemon, addr)
+char *daemon;
+struct sockaddr_in *addr;
+{
+ struct hostent *hp;
+ char **sp;
+ char *tmpname;
+
+ /* Check the IP address first. */
+ if (hosts_ctl(daemon, "", inet_ntoa(addr->sin_addr), ""))
+ return 1;
+
+ /* Check the hostname. */
+ hp = gethostbyaddr ((const char *) &(addr->sin_addr),
+ sizeof (addr->sin_addr), AF_INET);
+
+ if (!hp)
+ return 0;
+
+ /* must make sure the hostent is authorative. */
+ tmpname = alloca (strlen (hp->h_name) + 1);
+ strcpy (tmpname, hp->h_name);
+ hp = gethostbyname(tmpname);
+ if (hp) {
+ /* now make sure the "addr->sin_addr" is on the list */
+ for (sp = hp->h_addr_list ; *sp ; sp++) {
+ if (memcmp(*sp, &(addr->sin_addr), hp->h_length)==0)
+ break;
+ }
+ if (!*sp)
+ /* it was a FAKE. */
+ return 0;
+ }
+ else
+ /* never heard of it. misconfigured DNS? */
+ return 0;
+
+ /* Check the official name first. */
+ if (hosts_ctl(daemon, "", hp->h_name, ""))
+ return 1;
+
+ /* Check aliases. */
+ for (sp = hp->h_aliases; *sp ; sp++) {
+ if (hosts_ctl(daemon, "", *sp, ""))
+ return 1;
+ }
+
+ /* No match */
+ return 0;
+}
+
+/* check_startup - additional startup code */
+
+void check_startup()
+{
+
+ /*
+ * Give up root privileges so that we can never allocate a privileged
+ * port when forwarding an rpc request.
+ *
+ * Fix 8/3/00 Philipp Knirsch: First lookup our rpc user. If we find it,
+ * switch to that uid, otherwise simply resue the old bin user and print
+ * out a warning in syslog.
+ */
+
+ struct passwd *pwent;
+
+ pwent = getpwnam("rpc");
+ if (pwent == NULL) {
+ syslog(LOG_WARNING, "user rpc not found, reverting to user bin");
+ if (setuid(1) == -1) {
+ syslog(LOG_ERR, "setuid(1) failed: %m");
+ exit(1);
+ }
+ }
+ else {
+ if (setuid(pwent->pw_uid) == -1) {
+ syslog(LOG_WARNING, "setuid() to rpc user failed: %m");
+ if (setuid(1) == -1) {
+ syslog(LOG_ERR, "setuid(1) failed: %m");
+ exit(1);
+ }
+ }
+ }
+
+ (void) signal(SIGINT, toggle_verboselog);
+}
+
+/* check_default - additional checks for NULL, DUMP, GETPORT and unknown */
+
+int
+check_default(daemon, addr, proc, prog)
+char *daemon;
+struct sockaddr_in *addr;
+u_long proc;
+u_long prog;
+{
+ if (!(from_local(addr) || good_client(daemon, addr))) {
+ log_bad_host(addr, proc, prog);
+ return (FALSE);
+ }
+ if (verboselog)
+ log_client(addr, proc, prog);
+ return (TRUE);
+}
+
+/* check_privileged_port - additional checks for privileged-port updates */
+int
+check_privileged_port(addr, proc, prog, port)
+struct sockaddr_in *addr;
+u_long proc;
+u_long prog;
+u_long port;
+{
+#ifdef CHECK_PORT
+ if (!legal_port(addr, port)) {
+ log_bad_port(addr, proc, prog);
+ return (FALSE);
+ }
+#endif
+ return (TRUE);
+}
+
+/* toggle_verboselog - toggle verbose logging flag */
+
+static void toggle_verboselog(sig)
+int sig;
+{
+ (void) signal(sig, toggle_verboselog);
+ verboselog = !verboselog;
+}
+
+/* logit - report events of interest via the syslog daemon */
+
+static void logit(severity, addr, procnum, prognum, text)
+int severity;
+struct sockaddr_in *addr;
+u_long procnum;
+u_long prognum;
+char *text;
+{
+ char *procname;
+ char procbuf[4 * sizeof(u_long)];
+ char *progname;
+ char progbuf[4 * sizeof(u_long)];
+ struct rpcent *rpc;
+
+ /*
+ * Fork off a process or the portmap daemon might hang while
+ * getrpcbynumber() or syslog() does its thing.
+ */
+
+ if (fork() == 0) {
+
+ /* Try to map program number to name. */
+
+ if (prognum == 0) {
+ progname = "";
+ } else if ((rpc = getrpcbynumber((int) prognum))) {
+ progname = rpc->r_name;
+ } else {
+ sprintf(progname = progbuf, "%lu", prognum);
+ }
+
+ /* Try to map procedure number to name. */
+
+ sprintf(procname = procbuf, "%lu", (u_long) procnum);
+
+ /* Write syslog record. */
+
+ syslog(severity, "connect from %s to %s(%s)%s",
+ inet_ntoa(addr->sin_addr), procname, progname, text);
+ exit(0);
+ }
+}
projects / nfs-utils.git / commitdiff