1 files changed, 48 insertions, 5 deletions

diff --git a/src/firejail/fs_hostname.c b/src/firejail/fs_hostname.c
index b2e1b4a99..535526409 100644
--- a/src/firejail/fs_hostname.c
+++ b/src/firejail/fs_hostname.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014-2016 Firejail Authors
+ * Copyright (C) 2014-2017 Firejail Authors
  *
  * This file is part of firejail project
  *
@@ -42,7 +42,7 @@ void fs_hostname(const char *hostname) {
         }
         
         // create a new /etc/hosts
-        if (stat("/etc/hosts", &s) == 0) {
+        if (cfg.hosts_file == NULL && stat("/etc/hosts", &s) == 0) {
                 if (arg_debug)
                         printf("Creating a new /etc/hosts file\n");
                 // copy /etc/host into our new file, and modify it on the fly
@@ -79,9 +79,7 @@ void fs_hostname(const char *hostname) {
                 fclose(fp2);
                 
                 // bind-mount the file on top of /etc/hostname
-                if (mount(RUN_HOSTS_FILE, "/etc/hosts", NULL, MS_BIND|MS_REC, NULL) < 0)
-                        errExit("mount bind /etc/hosts");
-                fs_logger("create /etc/hosts");
+                fs_mount_hosts_file();
         }
         return;
 
@@ -129,4 +127,49 @@ void fs_resolvconf(void) {
         }
 }
 
+char *fs_check_hosts_fiile(const char *fname) {
+        assert(fname);
+        invalid_filename(fname);
+        char *rv = expand_home(fname, cfg.homedir);
+
+        // no a link
+        if (is_link(rv))
+                goto errexit;
         
+        // the user has read access to the file
+        if (access(rv, R_OK))
+                goto errexit;
+
+        return rv;
+errexit:
+        fprintf(stderr, "Error: invalid file %s\n", fname);
+        exit(1);
+}
+
+void fs_store_hosts_file(void) {
+        copy_file_from_user_to_root(cfg.hosts_file, RUN_HOSTS_FILE, 0, 0, 0644); // root needed
+}
+
+void fs_mount_hosts_file(void) {
+        // check /etc/hosts file
+        struct stat s;
+        if (stat("/etc/hosts", &s) == -1)
+                goto errexit;
+        // not a link
+        if (is_link("/etc/hosts"))
+                goto errexit;
+        // owned by root
+        if (s.st_uid != 0)
+                goto errexit;
+
+        // bind-mount the file on top of /etc/hostname
+        if (mount(RUN_HOSTS_FILE, "/etc/hosts", NULL, MS_BIND|MS_REC, NULL) < 0)
+                errExit("mount bind /etc/hosts");
+        fs_logger("create /etc/hosts");
+        return;
+
+errexit:
+        fprintf(stderr, "Error: invalid /etc/hosts file\n");
+        exit(1);
+}
+