From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 17 Jan 2018 10:56:52 +0000 (+0100)
Subject: fs-util: extra safety checks on chase_symlinks() root parameter
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=d569509362723ee91d86feb0f139f2e874cce9d9;p=elogind.git

fs-util: extra safety checks on chase_symlinks() root parameter

Let's handle root="" and root="/" safely.
---

diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index 32b1fb605..7a05e22ea 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -39,6 +39,7 @@
 #include "mkdir.h"
 #include "parse-util.h"
 #include "path-util.h"
+//#include "process-util.h"
 #include "stat-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
@@ -671,6 +672,14 @@ int chase_symlinks(const char *path, const char *original_root, unsigned flags,
          * function what to do when encountering a symlink with an absolute path as directory: prefix it by the
          * specified path. */
 
+        if (original_root) {
+                if (isempty(original_root)) /* What's this even supposed to mean? */
+                        return -EINVAL;
+
+                if (path_equal(original_root, "/")) /* A root directory of "/" is identical to none */
+                        original_root = NULL;
+        }
+
         if (original_root) {
                 r = path_make_absolute_cwd(original_root, &root);
                 if (r < 0)