get an unreserved port if not root; required now that rresvport fails

for non-root per bugno 70

diff --git a/usr.bin/rlogin/kcmd.c b/usr.bin/rlogin/kcmd.c
index cee5203..3da92f4 100644 (file)
--- a/usr.bin/rlogin/kcmd.c
+++ b/usr.bin/rlogin/kcmd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kcmd.c,v 1.6 1996/10/18 17:17:09 tholo Exp $  */
+/*     $OpenBSD: kcmd.c,v 1.7 1997/04/12 19:54:50 rees Exp $   */
 /*     $NetBSD: kcmd.c,v 1.2 1995/03/21 07:58:32 cgd Exp $     */
 
 /*
@@ -39,7 +39,7 @@
 static char Xsccsid[] = "derived from @(#)rcmd.c 5.17 (Berkeley) 6/27/88";
 static char sccsid[] = "@(#)kcmd.c     8.2 (Berkeley) 8/19/93";
 #else
-static char rcsid[] = "$OpenBSD: kcmd.c,v 1.6 1996/10/18 17:17:09 tholo Exp $";
+static char rcsid[] = "$OpenBSD: kcmd.c,v 1.7 1997/04/12 19:54:50 rees Exp $";
 #endif
 #endif /* not lint */
 
@@ -71,6 +71,8 @@ static char rcsid[] = "$OpenBSD: kcmd.c,v 1.6 1996/10/18 17:17:09 tholo Exp $";
 
 #define        START_PORT      5120     /* arbitrary */
 
+int    getport __P((int *));
+
 int
 kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
     cred, schedule, msg_data, laddr, faddr, authopts)
@@ -92,11 +94,7 @@ kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
        long oldmask;
        struct sockaddr_in sin, from;
        char c;
-#ifdef ATHENA_COMPAT
        int lport = IPPORT_RESERVED - 1;
-#else
-       int lport = START_PORT;
-#endif
        struct hostent *hp;
        int rc;
        char *host_save;
@@ -120,7 +118,7 @@ kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
 
        oldmask = sigblock(sigmask(SIGURG));
        for (;;) {
-               s = rresvport(&lport);
+               s = getport(&lport);
                if (s < 0) {
                        if (errno == EAGAIN)
                                fprintf(stderr,
@@ -175,7 +173,7 @@ kcmd(sock, ahost, rport, locuser, remuser, cmd, fd2p, ticket, service, realm,
                lport = 0;
        } else {
                char num[8];
-               int s2 = rresvport(&lport), s3;
+               int s2 = getport(&lport), s3;
                int len = sizeof(from);
 
                if (s2 < 0) {
@@ -276,3 +274,47 @@ bad:
        sigsetmask(oldmask);
        return (status);
 }
+
+int
+getport(alport)
+       int *alport;
+{
+       struct sockaddr_in sin;
+       int s;
+
+       /* First try to get a "reserved" [sic] port, for interoperability with
+          broken klogind (aix, e.g.) */
+
+       s = rresvport(alport);
+       if (s >= 0)
+               return s;
+
+       /* Failed; if EACCES, we're not root, so just get an unreserved port
+          and hope that's good enough */
+
+       if (errno != EACCES)
+               return -1;
+
+       if (*alport < IPPORT_RESERVED)
+               *alport = START_PORT;
+       sin.sin_family = AF_INET;
+       sin.sin_addr.s_addr = INADDR_ANY;
+       s = socket(AF_INET, SOCK_STREAM, 0);
+       if (s < 0)
+               return (-1);
+       for (;;) {
+               sin.sin_port = htons((u_short)*alport);
+               if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
+                       return (s);
+               if (errno != EADDRINUSE) {
+                       (void) close(s);
+                       return (-1);
+               }
+               (*alport)--;
+               if (*alport == IPPORT_RESERVED) {
+                       (void) close(s);
+                       errno = EAGAIN;         /* close */
+                       return (-1);
+               }
+       }
+}