Merge pull request #124 from pwssOrg/46-compare-hash-values-previous-vs-new-scans

Hash comparison between scans

Author: lilstiffy

File-Integrity-Scanner/src/main/java/org/pwss/file_integrity_scanner/component/FileHashComputer.java

@@ -1,7 +1,9 @@
 package org.pwss.file_integrity_scanner.component;
 
 import lib.pwss.hash.FileHashHandler;
+import lib.pwss.hash.compare.util.HashCompareUtil;
 import lib.pwss.hash.model.HashForFilesOutput;
+import org.pwss.file_integrity_scanner.msr.domain.model.entities.checksum.Checksum;
 import org.springframework.stereotype.Component;
 
 import java.io.File;
@@ -27,4 +29,21 @@ public FileHashComputer() {
     public HashForFilesOutput computeHashes(File file) {
         return fileHashHandler.GetAllHashes(file);
     }
+
+    /**
+     * Compares the hashes of two checksum objects.
+     * <p>
+     * This method compares the SHA-256, SHA-3, and Blake2b hashes of the provided
+     * checksum objects using XOR and Java's equals method. It returns true only if
+     * all three hash comparisons match.
+     *
+     * @param first  the first checksum object to compare
+     * @param second the second checksum object to compare
+     * @return true if all hash comparisons match, false otherwise
+     */
+    public boolean compareHashes(Checksum first, Checksum second) {
+        return HashCompareUtil.compareUsingXorAndJavaEquals(first.getChecksumSha256(), second.getChecksumSha256()) &&
+                HashCompareUtil.compareUsingXorAndJavaEquals(first.getChecksumSha3(), second.getChecksumSha3()) &&
+                HashCompareUtil.compareUsingXorAndJavaEquals(first.getChecksumBlake2b(), second.getChecksumBlake2b());
+    }
 }

File-Integrity-Scanner/src/main/java/org/pwss/file_integrity_scanner/msr/repository/ChecksumRepository.java

@@ -1,9 +1,14 @@
 package org.pwss.file_integrity_scanner.msr.repository;
 
 import org.pwss.file_integrity_scanner.msr.domain.model.entities.checksum.Checksum;
+import org.pwss.file_integrity_scanner.msr.domain.model.entities.file.File;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
+import java.util.List;
+import java.util.Optional;
+
 @Repository
 public interface ChecksumRepository extends JpaRepository<Checksum, Long> {
+    Optional<List<Checksum>> findByFile(File file);
 }

File-Integrity-Scanner/src/main/java/org/pwss/file_integrity_scanner/msr/service/checksum/ChecksumService.java

@@ -2,8 +2,23 @@
 
 
 import org.pwss.file_integrity_scanner.msr.domain.model.entities.checksum.Checksum;
+import org.pwss.file_integrity_scanner.msr.domain.model.entities.file.File;
+
+import java.util.List;
 
 public interface ChecksumService {
+
+    /**
+     * Retrieves a list of checksums associated with the specified file.
+     * <p>
+     * This method queries the database to find all checksum entities
+     * that are linked to the given file.
+     *
+     * @param file the file for which to retrieve associated checksums
+     * @return a list of checksums associated with the specified file
+     */
+    List<Checksum> findByFile(File file);
+
     /**
      * Saves a checksum entity to the database.
      *

File-Integrity-Scanner/src/main/java/org/pwss/file_integrity_scanner/msr/service/checksum/ChecksumServiceImpl.java

@@ -1,16 +1,37 @@
 package org.pwss.file_integrity_scanner.msr.service.checksum;
 
 import org.pwss.file_integrity_scanner.msr.domain.model.entities.checksum.Checksum;
+import org.pwss.file_integrity_scanner.msr.domain.model.entities.file.File;
 import org.pwss.file_integrity_scanner.msr.repository.ChecksumRepository;
 import org.pwss.file_integrity_scanner.msr.service.BaseService;
 import org.springframework.stereotype.Service;
 
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
 
 @Service
 public class ChecksumServiceImpl extends BaseService<ChecksumRepository> implements ChecksumService {
 
+    private final org.slf4j.Logger log;
+
     public ChecksumServiceImpl(ChecksumRepository repository) {
         super(repository);
+        this.log = org.slf4j.LoggerFactory.getLogger(ChecksumServiceImpl.class);
+    }
+
+    @Override
+    public List<Checksum> findByFile(File file) {
+        Optional<List<Checksum>> mOptional = repository.findByFile(file);
+
+        if (mOptional.isPresent()) {
+            return mOptional.get();
+        } else {
+            log.warn("No checksums found for file: {}", file.getPath());
+            return Collections.emptyList();
+        }
+
     }
 
     @Override

File-Integrity-Scanner/src/main/java/org/pwss/file_integrity_scanner/msr/service/scan/ScanServiceImpl.java

@@ -53,13 +53,16 @@ public class ScanServiceImpl extends BaseService<ScanRepository> implements Scan
     private final FileHashComputer fileHashComputer;
 
     private final org.slf4j.Logger log;
-
     private final DateTimeFormatter timeAndDateStringForLogFormat;
+
+    // Map to hold active scan tasks, keyed by directory path
     private final ConcurrentMap<String, ScanTaskState> activeScanTasks;
+
     // Flag to indicate if an ongoing scan should be stopped
     private boolean stopRequested = false;
 
-    private final int SCAN_TASK_MONITOR_DELAY = 5000; // Delay in milliseconds for monitoring scan tasks
+    // Delay in milliseconds for monitoring scan tasks
+    private final int SCAN_TASK_MONITOR_DELAY = 5000;
 
     @Autowired
     public ScanServiceImpl(ScanRepository repository,
@@ -282,22 +285,14 @@ private void processFile(File file, Scan scanInstance) {
 
             MonitoredDirectory mDirectory = scanInstance.getMonitoredDirectory();
 
-            if (monitoredDirectoryService.isBaseLineEstablished(mDirectory)) {
-
-                // Compare current hash to previous hash (Ticket #46)
-
-            } else {
-                // Scan without comparing hashes for this Monitored Directory
-            }
-
             if (fileInDatabase) {
                 // Fetch existing entity and update fields
                 fileEntity = fileService.findByPath(file.getPath());
                 fileEntity.setSize(file.length());
                 OffsetDateTime lastModified = Instant.ofEpochMilli(file.lastModified())
                         .atOffset(ZoneOffset.UTC);
                 fileEntity.setMtime(lastModified);
-                log.info("Updating existing file in DB: {}", fileEntity.getPath());
+                log.debug("Updating existing file in DB: {}", fileEntity.getPath());
             } else {
                 // Create new entity
                 fileEntity = new org.pwss.file_integrity_scanner.msr.domain.model.entities.file.File();
@@ -308,22 +303,39 @@ private void processFile(File file, Scan scanInstance) {
                 OffsetDateTime lastModified = Instant.ofEpochMilli(file.lastModified())
                         .atOffset(ZoneOffset.UTC);
                 fileEntity.setMtime(lastModified);
-                log.info("Adding new file to DB: {}", fileEntity.getPath());
+                log.debug("Adding new file to DB: {}", fileEntity.getPath());
             }
 
             fileService.save(fileEntity);
 
-            Checksum checksums = new Checksum();
-            checksums.setChecksumSha256(computedHashes.sha256());
-            checksums.setChecksumSha3(computedHashes.sha3());
-            checksums.setChecksumBlake2b(computedHashes.blake2());
-            checksums.setFile(fileEntity);
-            checksumService.save(checksums);
+            Checksum checksum = new Checksum();
+            checksum.setChecksumSha256(computedHashes.sha256());
+            checksum.setChecksumSha3(computedHashes.sha3());
+            checksum.setChecksumBlake2b(computedHashes.blake2());
+            checksum.setFile(fileEntity);
+            checksumService.save(checksum);
+
+            // If the baseline is established, check if the file has changed
+            if (monitoredDirectoryService.isBaseLineEstablished(mDirectory)) {
+                List<Checksum> dbChecksums = checksumService.findByFile(fileEntity);
+                if (!dbChecksums.isEmpty()) {
+                    // TODO: Maybe not getFirst but let's discuss this later
+                    Checksum oldChecksum = dbChecksums.getFirst();
+                    if (fileHashComputer.compareHashes(oldChecksum, checksum)) {
+                        log.info("File {} has not changed since last scan ✅", fileEntity.getPath());
+                    } else {
+                        log.warn("File {} has changed since last scan ⚠️", fileEntity.getPath());
+                        // TODO: Figure out what to do with changed files, add some notes to scan summary?
+                    }
+                } else {
+                    log.info("No existing checksum found for file from prior scans {}", fileEntity.getPath());
+                }
+            }
 
             ScanSummary scanSummary = new ScanSummary();
             scanSummary.setFile(fileEntity);
             scanSummary.setScan(scanInstance);
-            scanSummary.setChecksum(checksums);
+            scanSummary.setChecksum(checksum);
             scanSummaryService.save(scanSummary);
         } catch (OutOfMemoryError memoryError) {
             log.warn("Out of memory error while processing file: {}. Skipping file.", file.getPath());