ncat: close on EOF by default

new --no-terminate option for backward compatibility (#2082270)

close-on-EOF.patch

@@ -0,0 +1,116 @@
+From c9e091aceaded2d2f82674609d060036ace9d22e Mon Sep 17 00:00:00 2001
+From: Tobias Girstmair <t-nmap@girst.at>
+Date: Sun, 7 Feb 2021 15:49:21 +0100
+Subject: [PATCH] Ncat: match traditional and OpenBSD netcat behaviour of
+ terminating on EOF
+
+Also implements a switch for backwards compatibility with the previous
+behaviour, --no-terminate. Previously discussed at
+https://seclists.org/nmap-dev/2017/q2/94
+
+Fixes #1779, #894 and #1413.
+---
+ ncat/docs/ncat.xml  | 13 +++++++++++++
+ ncat/ncat_connect.c |  8 ++++----
+ ncat/ncat_core.c    |  1 +
+ ncat/ncat_core.h    |  1 +
+ ncat/ncat_main.c    |  2 ++
+ 5 files changed, 21 insertions(+), 4 deletions(-)
+
+diff --git a/ncat/docs/ncat.xml b/ncat/docs/ncat.xml
+index 653ae36a2..39c4d587b 100644
+--- a/ncat/docs/ncat.xml
++++ b/ncat/docs/ncat.xml
+@@ -874,6 +874,19 @@
+         </listitem>
+       </varlistentry>
+ 
++      <varlistentry>
++        <term>
++          <option>--no-terminate</option> (Do not terminate on stdin/socket EOF)
++          <indexterm><primary><option>--no-terminate</option> (Ncat option)</primary></indexterm>
++        </term>
++        <listitem>
++          <para>If this option is passed, Ncat will not terminate when EOF is
++          seen on the socket or stdin when connected over TCP. This used to be
++          the default in Ncat in the past, and is provided for
++          backwards-compatibility.</para>
++        </listitem>
++      </varlistentry>
++
+       <varlistentry>
+         <term>
+           <option>-n</option>,
+diff --git a/ncat/ncat_connect.c b/ncat/ncat_connect.c
+index f59dd4372..dffec9a91 100644
+--- a/ncat/ncat_connect.c
++++ b/ncat/ncat_connect.c
+@@ -1274,8 +1274,8 @@ static void read_stdin_handler(nsock_pool nsp, nsock_event evt, void *data)
+     if (status == NSE_STATUS_EOF) {
+         if (!o.noshutdown)
+             shutdown(nsock_iod_get_sd(cs.sock_nsi), SHUT_WR);
+-        /* In --send-only mode or non-TCP mode, exit after EOF on stdin. */
+-        if (o.proto != IPPROTO_TCP || (o.proto == IPPROTO_TCP && o.sendonly))
++        /* Unless --no-terminate is specified, exit after EOF on stdin. */
++        if (o.proto != IPPROTO_TCP || !o.noterminate)
+             nsock_loop_quit(nsp);
+         return;
+     } else if (status == NSE_STATUS_ERROR) {
+@@ -1325,8 +1325,8 @@ static void read_socket_handler(nsock_pool nsp, nsock_event evt, void *data)
+ #else
+         Close(STDOUT_FILENO);
+ #endif
+-        /* In --recv-only mode or non-TCP mode, exit after EOF on the socket. */
+-        if (o.proto != IPPROTO_TCP || (o.proto == IPPROTO_TCP && o.recvonly))
++        /* Unless --no-terminate is specified, exit after EOF on the socket. */
++        if (o.proto != IPPROTO_TCP || !o.noterminate)
+             nsock_loop_quit(nsp);
+         return;
+     } else if (status == NSE_STATUS_ERROR) {
+diff --git a/ncat/ncat_core.c b/ncat/ncat_core.c
+index 7c39e5d36..d5e5d7d68 100644
+--- a/ncat/ncat_core.c
++++ b/ncat/ncat_core.c
+@@ -107,6 +107,7 @@ void options_init(void)
+     o.sendonly = 0;
+     o.recvonly = 0;
+     o.noshutdown = 0;
++    o.noterminate = 0;
+     o.telnet = 0;
+     o.linedelay = 0;
+     o.chat = 0;
+diff --git a/ncat/ncat_core.h b/ncat/ncat_core.h
+index f03813dc5..9bd751264 100644
+--- a/ncat/ncat_core.h
++++ b/ncat/ncat_core.h
+@@ -111,6 +111,7 @@ struct options {
+     int sendonly;
+     int recvonly;
+     int noshutdown;
++    int noterminate;
+     int telnet;
+     int linedelay;
+     int chat;
+diff --git a/ncat/ncat_main.c b/ncat/ncat_main.c
+index 2792a6ac2..d49398f5f 100644
+--- a/ncat/ncat_main.c
++++ b/ncat/ncat_main.c
+@@ -263,6 +263,7 @@ int main(int argc, char *argv[])
+         {"source",          required_argument,  NULL,         's'},
+         {"send-only",       no_argument,        &o.sendonly,  1},
+         {"no-shutdown",     no_argument,        &o.noshutdown,1},
++        {"no-terminate",    no_argument,        &o.noterminate,1},
+         {"broker",          no_argument,        NULL,         0},
+         {"chat",            no_argument,        NULL,         0},
+         {"talk",            no_argument,        NULL,         0},
+@@ -615,6 +616,7 @@ int main(int argc, char *argv[])
+ "      --send-only            Only send data, ignoring received; quit on EOF\n"
+ "      --recv-only            Only receive data, never send anything\n"
+ "      --no-shutdown          Continue half-duplex when receiving EOF on stdin\n"
++"      --no-terminate         Do not exit when EOF is received on socket/stdin\n"
+ "      --allow                Allow only given hosts to connect to Ncat\n"
+ "      --allowfile            A file of hosts allowed to connect to Ncat\n"
+ "      --deny                 Deny given hosts from connecting to Ncat\n"
+-- 
+2.35.1
+

nmap.spec

@@ -7,7 +7,7 @@ Name: nmap
 Epoch: 3
 Version: 7.92
 #global prerelease TEST5
-Release: 2%{?dist}
+Release: 3%{?dist}
 Summary: Network exploration tool and security scanner
 URL: http://nmap.org/
 # Uses combination of licenses based on GPL license, but with extra modification
@@ -30,6 +30,7 @@ Patch3: ncat_reg_stdin.diff
 Patch4: nmap-6.25-displayerror.patch
 # https://github.com/nmap/nmap/pull/2247
 Patch7: nmap_resolve_config.patch
+Patch8: close-on-EOF.patch
 
 
 BuildRequires: automake make
@@ -153,6 +154,10 @@ fi
 %{_mandir}/man1/ncat.1.gz
 
 %changelog
+* Thu May 05 2022 Martin Osvald <mosvald@redhat.com> - 3:7.92-3
+- ncat: close on EOF by default, new --no-terminate option
+  for backward compatibility (#2082270)
+
 * Tue Feb 22 2022 Martin Osvald <mosvald@redhat.com> - 3:7.92-1
 - New version 7.92