[Openvpn-devel] [XS] Change in openvpn[master]: sitnl: set FD_CLOEXEC on socket to prevent abuse

[ordex (C. Review) <ge...@op...>]

Attention is currently required from: flichtenheld, ordex, plaisthos.

Hello flichtenheld, plaisthos, 

I'd like you to reexamine a change. Please visit

    http://gerrit.openvpn.net/c/openvpn/+/1314?usp=email

to look at the new patch set (#4).


Change subject: sitnl: set FD_CLOEXEC on socket to prevent abuse
......................................................................

sitnl: set FD_CLOEXEC on socket to prevent abuse

Since OpenVPN spawns various child processes, it is important
that sockets are closed after calling exec.

The sitnl socket didn't have the right flag set, resulting
in it surviving in, for example, connect/disconnect scripts
and giving the latter a chance to abuse the socket.

Ensure this doesn't happen by setting FD_CLOEXEC on
this socket right after creation.

Reported-by: ZeroPath (https://zeropath.com/)
Change-Id: I54845bf4dd17d06cfc3b402f188795f74f4b1d3e
Signed-off-by: Antonio Quartulli <an...@ma...>
---
M CMakeLists.txt
M src/openvpn/networking_sitnl.c
M tests/unit_tests/openvpn/Makefile.am
3 files changed, 6 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.openvpn.net:29418/openvpn refs/changes/14/1314/4

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5954a6e..bf754f3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -923,6 +923,7 @@
             src/openvpn/crypto_openssl.c
             src/openvpn/crypto.c
             src/openvpn/crypto_epoch.c
+            src/openvpn/fdmisc.c
             src/openvpn/otime.c
             src/openvpn/packet_id.c
             )
diff --git a/src/openvpn/networking_sitnl.c b/src/openvpn/networking_sitnl.c
index b3adb16..3e20b70 100644
--- a/src/openvpn/networking_sitnl.c
+++ b/src/openvpn/networking_sitnl.c
@@ -27,6 +27,7 @@
 
 #include "dco.h"
 #include "errlevel.h"
+#include "fdmisc.h"
 #include "buffer.h"
 #include "misc.h"
 #include "networking.h"
@@ -181,6 +182,9 @@
         return fd;
     }
 
+    /* set close on exec to avoid child processes access the socket */
+    set_cloexec(fd);
+
     if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) < 0)
     {
         msg(M_WARN | M_ERRNO, "%s: SO_SNDBUF", __func__);
diff --git a/tests/unit_tests/openvpn/Makefile.am b/tests/unit_tests/openvpn/Makefile.am
index 997703a..0f13172 100644
--- a/tests/unit_tests/openvpn/Makefile.am
+++ b/tests/unit_tests/openvpn/Makefile.am
@@ -196,6 +196,7 @@
 	$(top_srcdir)/src/openvpn/crypto_epoch.c \
 	$(top_srcdir)/src/openvpn/crypto_mbedtls.c \
 	$(top_srcdir)/src/openvpn/crypto_openssl.c \
+	$(top_srcdir)/src/openvpn/fdmisc.c \
 	$(top_srcdir)/src/openvpn/otime.c \
 	$(top_srcdir)/src/openvpn/packet_id.c \
 	$(top_srcdir)/src/openvpn/platform.c

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Gerrit-MessageType: newpatchset
Gerrit-Project: openvpn
Gerrit-Branch: master
Gerrit-Change-Id: I54845bf4dd17d06cfc3b402f188795f74f4b1d3e
Gerrit-Change-Number: 1314
Gerrit-PatchSet: 4
Gerrit-Owner: ordex <an...@ma...>
Gerrit-Reviewer: flichtenheld <fr...@li...>
Gerrit-Reviewer: plaisthos <arn...@rf...>
Gerrit-CC: openvpn-devel <ope...@li...>
Gerrit-Attention: plaisthos <arn...@rf...>
Gerrit-Attention: flichtenheld <fr...@li...>
Gerrit-Attention: ordex <an...@ma...>