From b115a99907618d7ff04e8d9323b2c66ce40c970a Mon Sep 17 00:00:00 2001
From: l-jonas <43265000+l-jonas@users.noreply.github.com>
Date: Sun, 9 Dec 2018 12:00:40 +0100
Subject: [PATCH] Path validation (#122)

* Remove isTrimmed path validation rule

* Include exact reason in path validation exceptions
---
 .../syncthing/java/core/utils/PathUtils.kt    | 47 ++++++++++++-------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/syncthing-core/src/main/kotlin/net/syncthing/java/core/utils/PathUtils.kt b/syncthing-core/src/main/kotlin/net/syncthing/java/core/utils/PathUtils.kt
index 9967005..4f6371b 100644
--- a/syncthing-core/src/main/kotlin/net/syncthing/java/core/utils/PathUtils.kt
+++ b/syncthing-core/src/main/kotlin/net/syncthing/java/core/utils/PathUtils.kt
@@ -34,42 +34,57 @@ object PathUtils {
         return pathSegments.contains(PARENT_PATH) or pathSegments.contains(CURRENT_PATH)
     }
 
-    private fun isTrimmed(value: String) = value.trim() == value
     private fun containsWindowsPathSeparator(path: String) = path.contains(PATH_SEPARATOR_WIN)
-    private fun startsWithPathSeperator(path: String) = path.startsWith(PATH_SEPARATOR)
-    private fun isValidPath(path: String) = (!containsRelativeElements(path)) and
-            (!containsWindowsPathSeparator(path)) and
-            path.isNotEmpty() and
-            (!startsWithPathSeperator(path)) and
-            isTrimmed(path)
+    private fun startsWithPathSeparator(path: String) = path.startsWith(PATH_SEPARATOR)
 
     private fun containsPathSeparator(file: String) = file.contains(PATH_SEPARATOR) or file.contains(PATH_SEPARATOR_WIN)
-    private fun isFilenameValid(file: String) = file.isNotBlank() and
-            (!containsPathSeparator(file)) and
-            isTrimmed(file)
 
     private fun assertPathValid(path: String) {
-        if (!isValidPath(path)) {
+        fun throwException(reason: String) {
             throw ExceptionDetailException(
-                    IllegalArgumentException("provided path is invalid"),
+                    IllegalArgumentException("provided path is invalid because it $reason"),
                     ExceptionDetails(
                             component = "PathUtils",
-                            details = "processed path: $path"
+                            details = "processed path: \"$path\""
                     )
             )
         }
+
+        if (containsRelativeElements(path)) {
+            throwException("contains relative path elements")
+        }
+
+        if (containsWindowsPathSeparator(path)) {
+            throwException("contains windows path separators")
+        }
+
+        if (path.isEmpty()) {
+            throwException("is empty")
+        }
+
+        if (startsWithPathSeparator(path)) {
+            throwException("starts with a path separator")
+        }
     }
 
     private fun assertFilenameValid(filename: String) {
-        if (!isFilenameValid(filename)) {
+        fun throwException(reason: String) {
             throw ExceptionDetailException(
-                    IllegalArgumentException("provided filename is invalid"),
+                    IllegalArgumentException("provided filename is invalid because the filename $reason"),
                     ExceptionDetails(
                             component = "PathUtils",
-                            details = "processed filename: $filename"
+                            details = "processed filename: \"$filename\""
                     )
             )
         }
+
+        if (filename.isBlank()) {
+            throwException("is blank")
+        }
+
+        if (containsPathSeparator(filename)) {
+            throwException("contains a path separator")
+        }
     }
 
     fun isParent(path: String): Boolean {