nc: fix "nc -nl -p LPORT RHOST" case (was expecting remote port 0). closes bug 837

function                                             old     new   delta
dolisten                                             742     830     +88

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 22 insertions, 9 deletions

diff --git a/networking/nc_bloaty.c b/networking/nc_bloaty.c
index 9d7c23dee..e14d512ed 100644
--- a/networking/nc_bloaty.c
+++ b/networking/nc_bloaty.c
@@ -340,16 +340,29 @@ create new one, and bind() it. TODO */
                         rr = accept(netfd, &remend.u.sa, &remend.len);
                         if (rr < 0)
                                 bb_perror_msg_and_die("accept");
-                        if (themaddr && memcmp(&remend.u.sa, &themaddr->u.sa, remend.len) != 0) {
-                                /* nc 1.10 bails out instead, and its error message
-                                 * is not suppressed by o_verbose */
-                                if (o_verbose) {
-                                        char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
-                                        bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
-                                        free(remaddr);
+                        if (themaddr) {
+                                int sv_port, port, r;
+
+                                sv_port = get_nport(&remend.u.sa); /* save */
+                                port = get_nport(&themaddr->u.sa);
+                                if (port == 0) {
+                                        /* "nc -nl -p LPORT RHOST" (w/o RPORT!):
+                                         * we should accept any remote port */
+                                        set_nport(&remend, 0); /* blot out remote port# */
+                                }
+                                r = memcmp(&remend.u.sa, &themaddr->u.sa, remend.len);
+                                set_nport(&remend, sv_port); /* restore */
+                                if (r != 0) {
+                                        /* nc 1.10 bails out instead, and its error message
+                                         * is not suppressed by o_verbose */
+                                        if (o_verbose) {
+                                                char *remaddr = xmalloc_sockaddr2dotted(&remend.u.sa);
+                                                bb_error_msg("connect from wrong ip/port %s ignored", remaddr);
+                                                free(remaddr);
+                                        }
+                                        close(rr);
+                                        goto again;
                                 }
-                                close(rr);
-                                goto again;
                         }
                         unarm();
                 } else