3 files changed, 81 insertions, 0 deletions

diff --git a/src/jailcheck/jailcheck.h b/src/jailcheck/jailcheck.h
index 32be1c978..be3104da3 100644
--- a/src/jailcheck/jailcheck.h
+++ b/src/jailcheck/jailcheck.h
@@ -53,6 +53,8 @@ void apparmor_test(pid_t pid);
 // seccomp.c
 void seccomp_test(pid_t pid);
 
+// network.c
+void network_test(void);
 // utils.c
 char *get_sudo_user(void);
 char *get_homedir(const char *user, uid_t *uid, gid_t *gid);
diff --git a/src/jailcheck/main.c b/src/jailcheck/main.c
index 4d642bf96..812ac5808 100644
--- a/src/jailcheck/main.c
+++ b/src/jailcheck/main.c
@@ -157,6 +157,7 @@ int main(int argc, char **argv) {
                         seccomp_test(pid);
                         fflush(0);
 
+                        // filesystem tests
                         pid_t child = fork();
                         if (child == -1)
                                 errExit("fork");
@@ -185,6 +186,28 @@ int main(int argc, char **argv) {
                         }
                         int status;
                         wait(&status);
+
+                        // network test
+                        child = fork();
+                        if (child == -1)
+                                errExit("fork");
+                        if (child == 0) {
+                                int rv = join_namespace(pid, "net");
+                                if (rv == 0)
+                                        network_test();
+                                else {
+                                        printf("   Error: I cannot join the process network stack\n");
+                                        exit(1);
+                                }
+
+                                // drop privileges in order not to trigger cleanup()
+                                if (setgid(user_gid) != 0)
+                                        errExit("setgid");
+                                if (setuid(user_uid) != 0)
+                                        errExit("setuid");
+                                return 0;
+                        }
+                        wait(&status);
                 }
         }
 
diff --git a/src/jailcheck/network.c b/src/jailcheck/network.c
new file mode 100644
index 000000000..636344e77
--- /dev/null
+++ b/src/jailcheck/network.c
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2014-2021 Firejail Authors
+ *
+ * This file is part of firejail project
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+#include "jailcheck.h"
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <linux/connector.h>
+#include <linux/netlink.h>
+#include <linux/if_link.h>
+#include <linux/sockios.h>
+#include <sys/ioctl.h>
+
+
+void network_test(void) {
+        // I am root running in a network namespace
+        struct ifaddrs *ifaddr, *ifa;
+        int found = 0;
+
+        // walk through the linked list
+        if (getifaddrs(&ifaddr) == -1)
+                errExit("getifaddrs");
+        for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+                if (strcmp(ifa->ifa_name, "lo") == 0)
+                        continue;
+                found = 1;
+                break;
+        }
+
+        freeifaddrs(ifaddr);
+
+        if (found)
+                printf("   Networking: enabled\n");
+        else
+                printf("   Networking: disabled\n");
+}
+
+
+