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Merge policies updates #527#530

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chlaplan wants to merge 9 commits into
MicrosoftDocs:mainfrom
chlaplan:Merge-policies-updates-#527
Open

Merge policies updates #527#530
chlaplan wants to merge 9 commits into
MicrosoftDocs:mainfrom
chlaplan:Merge-policies-updates-#527

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@chlaplan chlaplan commented Jun 4, 2026

#527

This pull request adds robust post-processing to the policy merge workflow, ensuring that the resulting merged policy is cleaner and less error-prone. The main enhancement is a new deduplication step that removes duplicate rules and references across merged policies, and resets the policy GUID as a best practice. This helps prevent redundant or conflicting rules and keeps the policy consistent.

Policy merge post-processing improvements:

  • After merging policies, the code now (1) generates a new policy GUID and (2) deduplicates rules and references in the merged policy. This is handled in MergePolicies_MergeControl by deserializing the merged policy, applying deduplication, resetting the GUID, and serializing it back.

Deduplication logic (in PolicyHelper):

  • Introduced the DeduplicateRules method, which removes duplicate Signers, FileRules (including Allow, Deny, FileAttrib), and EKUs by comparing their content (excluding IDs). It also remaps references to point to surviving rules and drops duplicate references.
  • Added helper methods to generate content-based keys for rules and signers, and to deduplicate references in arrays such as FileRuleRef, AllowedSigner, DeniedSigner, CiSigner, etc., ensuring all references are unique after merging.
  • Updated using directives to include System.Linq, required for deduplication logic.

chlaplan and others added 9 commits May 4, 2026 17:44
• FolderHashScanForm.cs — New dialog for folder-based hash file scanning with browse, subfolder toggle, file checklist, and hash type selection
Modified Files
CustomRuleConditionsPanel.cs
• Added hash mode panel with Single File, Multiple Files radio buttons and Folder Scan... button
• "Folder Scan..." button directly opens FolderHashScanForm dialog
• Multi-file and folder scan modes batch files into a single FolderScan-type rule using New-CIPolicy -ScanPath (instead of one PowerShell call per file)
• Selected files are copied to a temp folder preserving subfolder structure from the source
• Stores SourceFolderPath and HashTypesToKeep on the rule for downstream processing
FolderHashScanForm.cs
• Browse folder with optional Include subfolders checkbox
• Scan Folder button enumerates files by common PE/script extensions
• Select All / Deselect All for the file checklist
• Hash type checkboxes: Hash SHA1, Hash SHA256, Hash Page SHA1, Hash Page SHA256, and All (toggle)
• Exposes SelectedFiles, SelectedHashTypes, SourceFolderPath, IncludeSubfolders, AllFilesSelected
• Dark mode support
SigningRules_Control.cs
• Added AddRuleToTableWithoutClosing() method to support batch rule insertion without closing the custom rules panel
Policy.cs (PolicyCustomRules class)
• Added HashTypesToKeep property (HashSet<string>) — hash types to retain when filtering generated policy XML
• Added SourceFolderPath property (string) — original folder path for FriendlyName correction
MainForm.cs
• Added using System.Linq
• FriendlyName fix: after scan, replaces temp folder path in each rule's FriendlyName with the original source folder path (preserving subfolders)
• Hash type filtering: removes unwanted hash types (Hash SHA1, Hash Page SHA256, etc.) from generated policy based on user's checkbox selections
• Progress bar improvements:
• ProcessCustomValueRules(BackgroundWorker, SiPolicy) now reports incremental progress 0–25% per rule
• ProcessSignerRules(BackgroundWorker, SiPolicy) shows "Processing rule X of Y ..." with accurate counts
• FolderScan shows phased status: "Scanning folder: ...", "Scan complete. Applying hash type filters ...", "Filtered: kept X of Y hash rules.", "Merging scanned policy rules ..."
• ProgressChanged handler respects custom UserState messages
This reverts commit 162dd88.
• Added -NoLogo -NonInteractive flags to PowerShell invocation to reduce startup overhead
• Fixed potential deadlock: moved StandardOutput.ReadToEnd() and StandardError.ReadToEnd() before WaitForExit() to prevent buffer-full hang

MainForm.cs
• Fixed progress bar stalling at 25% during Folder Scan by reporting progress after skipping non-applicable rules
• Added mid-scan progress report (~55%) before CreateScannedPolicyFromPS(PolicyCustomRules, string, string) so UI shows activity during long scans
• Updated progress status text: "Scanning and processing rules (this may take a few minutes) ..." for the 25-80% range
…cy GUID, and deduplicate rules (signers and file rules with identical content but different IDs).

2. Re-serialize.
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