HDFS-9123. Copying from the root to a subdirectory should be forbidden. (Wei-Chiu Chuang via Yongjun Zhang)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/CommandWithDestination.java

@@ -238,7 +238,13 @@ abstract class CommandWithDestination extends FsCommand {
         e.setTargetPath(dstPath.toString());
         throw e;
       }
-      if (dstPath.startsWith(srcPath+Path.SEPARATOR)) {
+      // When a path is normalized, all trailing slashes are removed
+      // except for the root
+      if(!srcPath.endsWith(Path.SEPARATOR)) {
+        srcPath += Path.SEPARATOR;
+      }
+
+      if(dstPath.startsWith(srcPath)) {
         PathIOException e = new PathIOException(src.toString(),
             "is a subdirectory of itself");
         e.setTargetPath(target.toString());

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1409,6 +1409,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-9076. Log full path instead of inodeId in DFSClient
     #closeAllFilesBeingWritten() (Surendra Singh Lilhore via vinayakumarb)
 
+    HDFS-9123. Copying from the root to a subdirectory should be forbidden.
+    (Wei-Chiu Chuang via Yongjun Zhang)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java

@@ -1384,6 +1384,19 @@ public class TestDFSShell {
                              e.getLocalizedMessage());
         }
         assertEquals(0, val);
+
+        // this should fail
+        args1[0] = "-cp";
+        args1[1] = "/";
+        args1[2] = "/test";
+        val = 0;
+        try {
+          val = shell.run(args1);
+        } catch (Exception e) {
+          System.err.println("Exception raised from DFSShell.run " +
+              e.getLocalizedMessage());
+        }
+        assertEquals(1, val);
       }
 
       // Verify -test -f negative case (missing file)