Fix CVE-2018-20685:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-20685

Patch copied from upstream source repository:

https://github.com/openssh/openssh-portable/commit/6010c0303a422a9c5fa8860c061bf7105eb7f8b2

From 6010c0303a422a9c5fa8860c061bf7105eb7f8b2 Mon Sep 17 00:00:00 2001
From: "djm@openbsd.org" <djm@openbsd.org>
Date: Fri, 16 Nov 2018 03:03:10 +0000
Subject: [PATCH] upstream: disallow empty incoming filename or ones that refer
 to the

current directory; based on report/patch from Harry Sintonen

OpenBSD-Commit-ID: f27651b30eaee2df49540ab68d030865c04f6de9
---
 scp.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/scp.c b/scp.c
index 60682c68..4f3fdcd3 100644
--- a/scp.c
+++ b/scp.c
#@@ -1,4 +1,4 @@
#-/* $OpenBSD: scp.c,v 1.197 2018/06/01 04:31:48 dtucker Exp $ */
#+/* $OpenBSD: scp.c,v 1.198 2018/11/16 03:03:10 djm Exp $ */
# /*
#  * scp - secure remote copy.  This is basically patched BSD rcp which
#  * uses ssh to do the data transfer (instead of using rcmd).
@@ -1106,7 +1106,8 @@ sink(int argc, char **argv)
 			SCREWUP("size out of range");
 		size = (off_t)ull;
 
-		if ((strchr(cp, '/') != NULL) || (strcmp(cp, "..") == 0)) {
+		if (*cp == '\0' || strchr(cp, '/') != NULL ||
+		    strcmp(cp, ".") == 0 || strcmp(cp, "..") == 0) {
 			run_err("error: unexpected filename: %s", cp);
 			exit(1);
 		}
-- 
2.20.1

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<tr><td><span title='2021-04-12 18:42:23 +0200'>2021-04-12</span></td><td><a href='/guix/commit/gnu/tests/networking.scm?id=68c9e0a56e008f19427bd213cf5b24bdd8fe5922'>gnu: tests: Test basic funtionality of the IPFS service.</a><span class='msg-avail'>...<span class='msg-tooltip'>It is tested whether the IPFS service listens
at the gateway and API ports and whether it
is possible to upload and download a bytevector.

* gnu/tests/networking.scm
  (%ipfs-os): New variable.
  (run-ipfs-test): New procedure.
  (%test-ipfs): New system test.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2020-07-11 23:36:32 +0200'>2020-07-11</span></td><td><a href='/guix/commit/gnu/tests/networking.scm?id=54461153dac6096a018e35a1d959e45b2c9dbb82'>tests: networking: Use 'net.ifnames=0' for the Open vSwitch test.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/tests/networking.scm (%openvswitch-os): Override KERNEL-ARGUMENTS.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-04-10 20:20:11 +0200'>2020-04-10</span></td><td><a href='/guix/commit/gnu/tests/networking.scm?id=6720616daaf711314827c157a660339990e5cb07'>tests: openvswitch: Use the absolute file name of ovs-vsctl.</a><span class='msg-avail'>...<span class='msg-tooltip'>This fixes a regression introduced in 8b9cad01e9619f53dc5a65892ca6a09ca5de3447
where ovs-vsctl would no longer be available in PATH.

* gnu/tests/networking.scm (run-openvswitch-test): Qualify "ovs-vsctl"
invocation by ungexping the OPENVSWITCH variable instead of assuming it's
available on PATH.
</span></span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2020-03-16 14:05:52 +0100'>2020-03-16</span></td><td><a href='/guix/commit/gnu/tests/networking.scm?id=ef0f5ff2a74e5e4dc49dfdd0ba6509a91281ddd5'>tests: dhcpd: Adjust network interface name.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a followup to 8e53fe2b91d2776bc1529e7b34967c8f1d9edc32.

* gnu/tests/networking.scm (dhcpd-v4-configuration)
(%dhcpd-os): Use "ens3" instead of "eth0".
</span></span></td><td>Ludovic Courtès</td></tr>