(nifi) branch main updated: NIFI-15653 Fix DeleteSFTP security check for dot directory path

[tu...@apache.org]

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asf-gitbox-commits pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/nifi.git


The following commit(s) were added to refs/heads/main by this push:
     new d7c74c7aeba NIFI-15653 Fix DeleteSFTP security check for dot directory path
d7c74c7aeba is described below

commit d7c74c7aeba36fa06cd2c7190054c8a003957248
Author: Rakesh Kumar Singh <rs...@gmail.com>
AuthorDate: Wed May 20 16:09:52 2026 +0530

    NIFI-15653 Fix DeleteSFTP security check for dot directory path
    
    When the Remote Path property is set to '.' (as produced by ListSFTP),
    Paths.get('.').normalize() returns an empty Path (''). Resolving a
    filename against that empty path yields a single-component relative
    path whose getParent() returns null, causing the directory-traversal
    security check to fail incorrectly and route every FlowFile to the
    failure relationship.
    
    Fix: when fileParent is null (single-component relative path), substitute
    Paths.get('') for the comparison. Both the empty normalized path and a
    null parent represent the implicit current directory, so the check now
    correctly passes. Path-traversal attempts (e.g. '../etc/passwd') still
    produce a non-empty parent that does not equal the empty directoryPath,
    so the security guard remains intact.
    
    Add TestDeleteSFTP.deletesFileWhenDirectoryPathIsDot() to cover the
    regression.
    
    This closes #11266.
    
    Signed-off-by: Peter Turcsanyi <tu...@apache.org>
---
 .../java/org/apache/nifi/processors/standard/DeleteSFTP.java |  3 ++-
 .../org/apache/nifi/processors/standard/TestDeleteSFTP.java  | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/DeleteSFTP.java b/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/DeleteSFTP.java
index 5d284d3437c..29b6845b7bb 100644
--- a/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/DeleteSFTP.java
+++ b/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/main/java/org/apache/nifi/processors/standard/DeleteSFTP.java
@@ -211,7 +211,8 @@ public class DeleteSFTP extends AbstractProcessor {
                         filename = context.getProperty(FILENAME).evaluateAttributeExpressions(flowFile).getValue();
                         final Path filePath = directoryPath.resolve(filename).normalize();
 
-                        if (!directoryPath.equals(filePath.getParent())) {
+                        final Path fileParent = filePath.getParent();
+                        if (!directoryPath.equals(fileParent == null ? Paths.get("") : fileParent)) {
                             final String errorMessage = "Attempting to delete file at path '%s' which is not a direct child of the directory '%s'"
                                     .formatted(filePath, directoryPath);
 
diff --git a/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestDeleteSFTP.java b/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestDeleteSFTP.java
index eeb91b82475..0ce6c5b50cd 100644
--- a/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestDeleteSFTP.java
+++ b/nifi-extension-bundles/nifi-standard-bundle/nifi-standard-processors/src/test/java/org/apache/nifi/processors/standard/TestDeleteSFTP.java
@@ -154,6 +154,18 @@ class TestDeleteSFTP {
         runner.assertAllFlowFilesTransferred(DeleteSFTP.REL_SUCCESS);
     }
 
+    @Test
+    void deletesFileWhenDirectoryPathIsDot() throws IOException {
+        final Path fileToDelete = Files.writeString(sshServerRootPath.resolve("test.txt"), "some text");
+        enqueue(".", fileToDelete.getFileName().toString());
+        assertExists(fileToDelete);
+
+        runner.run();
+
+        assertNotExists(fileToDelete);
+        runner.assertAllFlowFilesTransferred(DeleteSFTP.REL_SUCCESS, 1);
+    }
+
     @Test
     void sendsFlowFileToFailureWhenFileIsNotADirectChildOfTheDirectory() throws IOException {
         final Path directoryPath = Files.createDirectories(sshServerRootPath.resolve("rel/path"));