Add guarded recovery for one selected leaf-file audit ACE

scripts/FileSaclRecovery.ps1

@@ -0,0 +1,183 @@
+# Recovery is limited to a single proven explicit addition on an existing leaf file.
+function Get-WelaFileSaclRecoveryKey {param($Value) ConvertTo-Json -InputObject $Value -Depth 30 -Compress}
+function Initialize-WelaFileSaclRecoveryNative {
+    $path=Join-Path $PSScriptRoot 'FileSaclRecoveryNative.cs';$bytes=[IO.File]::ReadAllBytes($path);$hash=Get-WelaArrivalHash $bytes
+    if (-not ('Wela.FileSaclRecovery.Descriptor' -as [type])) {
+        $source=[Text.UTF8Encoding]::new($false,$true).GetString($bytes).TrimStart([char]0xfeff)
+        $marker='__WELA_FILE_SACL_RECOVERY_SOURCE_SHA256__'
+        if (($source.Split(@($marker),[StringSplitOptions]::None)).Count -ne 2) {throw 'Unexpected native recovery source binding.'}
+        Add-Type -TypeDefinition $source.Replace($marker,$hash) -ErrorAction Stop
+    }
+    if ([Wela.FileSaclRecovery.Descriptor]::SourceSha256 -cne $hash) {throw 'Loaded file recovery helper differs from current source; start a fresh PowerShell process.'}
+}
+function Get-WelaFileSaclRecoverySources {
+    $sources=[ordered]@{}
+    foreach ($path in @('WELA.ps1','scripts/FileSaclRecovery.ps1','scripts/FileSaclRecoveryNative.cs','scripts/SelectedSaclConfiguration.ps1','scripts/SelectedSaclNative.cs','scripts/SelectedSaclDescendants.ps1','scripts/TargetedSaclPlanning.ps1','scripts/ControlApplicability.ps1','scripts/Configuration.ps1','config/control_applicability.json','modules/NativeProviders.psm1','scripts/EvtxRecovery.ps1','scripts/WefArrival.ps1','modules/AuditProfiles.psm1','modules/AuditCatalog.psm1','config/audit_profiles.json','config/audit_sacl_targets.json')) {
+        $sources[$path]=(Get-FileHash -LiteralPath (Join-Path (Split-Path $PSScriptRoot -Parent) $path) -Algorithm SHA256 -ErrorAction Stop).Hash.ToLowerInvariant()
+    }
+    [pscustomobject]$sources
+}
+function Get-WelaFileSaclRecoveryOperator {
+    if ($env:OS -ne 'Windows_NT' -or -not [Environment]::Is64BitProcess) {throw 'File SACL recovery requires native 64-bit Windows.'}
+    $thread=[Security.Principal.WindowsIdentity]::GetCurrent($true)
+    if ($thread) {$thread.Dispose();throw 'Impersonated recovery is unsupported.'}
+    $identity=[Security.Principal.WindowsIdentity]::GetCurrent()
+    try {
+        if (-not ([Security.Principal.WindowsPrincipal]::new($identity)).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) {throw 'File SACL recovery requires the actual elevated operator.'}
+        $key=[Microsoft.Win32.Registry]::LocalMachine.OpenSubKey('SOFTWARE\Microsoft\Cryptography',$false)
+        if (-not $key) {throw 'Machine identity is unavailable.'}
+        try {$machine=$key.GetValue('MachineGuid');if ($key.GetValueKind('MachineGuid') -ne 'String' -or $machine -isnot [string]) {throw 'Machine identity is mistyped.'}} finally {$key.Dispose()}
+        [guid]$parsed=[guid]::Empty;if (-not [guid]::TryParse($machine,[ref]$parsed) -or $parsed -eq [guid]::Empty) {throw 'Machine identity is invalid.'}
+        [pscustomobject][ordered]@{Computer=[Environment]::MachineName;MachineGuid=$parsed.ToString();UserSid=$identity.User.Value;Groups=@($identity.Groups|ForEach-Object Value|Sort-Object);ElevatedAdministrator=$true;Impersonation='Absent'}
+    } finally {$identity.Dispose()}
+}
+function Read-WelaFileSaclRecoveryInput {
+    param([string]$Path)
+    $full=Resolve-WelaArrivalPath $Path
+    $stream=[IO.File]::Open($full,[IO.FileMode]::Open,[IO.FileAccess]::Read,[IO.FileShare]::Read)
+    try {
+        if ($stream.Length -lt 1 -or $stream.Length -gt 4194304) {throw 'Recovery JSON must contain 1 byte through four MiB.'}
+        $bytes=New-Object byte[] ([int]$stream.Length);$offset=0
+        while ($offset -lt $bytes.Length) {$count=$stream.Read($bytes,$offset,$bytes.Length-$offset);if ($count -eq 0) {throw 'Recovery input changed during reading.'};$offset+=$count}
+        if ($stream.Length -ne $bytes.Length) {throw 'Recovery input length changed.'}
+    } finally {$stream.Dispose()}
+    $text=[Text.UTF8Encoding]::new($false,$true).GetString($bytes).TrimStart([char]0xfeff)
+    [pscustomobject]@{Path=$full;Sha256=(Get-WelaArrivalHash $bytes);Bytes=$bytes.Length;Data=(ConvertFrom-WelaEvtxJson $text)}
+}
+function Assert-WelaFileSaclRecoverySnapshot {
+    param($Snapshot,$Definition)
+    Assert-WelaEvtxObject $Snapshot @('Path','Kind','Identity','IsDirectory','DescriptorBase64','Owner','Group','DaclBase64','ControlFlags','SecurityInformation','DescriptorScope','Aces')
+    if ($Snapshot.Kind -cne 'FileSystem' -or $Snapshot.IsDirectory -isnot [bool] -or $Snapshot.IsDirectory -or $Snapshot.Path -cne $Definition.Path -or $Snapshot.Identity -cnotmatch '^[0-9]+:[0-9]+:[0-9]+:[0-9]+$' -or $Snapshot.Aces -isnot [array]) {throw 'Only exact historical leaf-file snapshots are supported.'}
+    $null=Get-WelaSelectedSaclSnapshotKey $Snapshot
+    foreach ($ace in $Snapshot.Aces) {
+        Assert-WelaEvtxObject $ace @('Binary','Type','Flags','Mask','Sid','Ordinary')
+        if ($ace.Ordinary -isnot [bool]) {throw 'Mistyped ACE metadata.'}
+        foreach ($name in @('Type','Flags','Mask')) {if ($ace.$name -isnot [int] -and $ace.$name -isnot [long]) {throw 'Mistyped ACE metadata.'}}
+    }
+    Initialize-WelaFileSaclRecoveryNative
+    $parsed=[Wela.FileSaclRecovery.Descriptor]::Observe($Snapshot.Path,$Snapshot.Identity,[Convert]::FromBase64String($Snapshot.DescriptorBase64))
+    if ((Get-WelaSelectedSaclSnapshotKey $parsed) -cne (Get-WelaSelectedSaclSnapshotKey $Snapshot)) {throw 'Historical snapshot metadata differs from its actual descriptor bytes.'}
+}
+function Get-WelaFileSaclRecoverySnapshot {
+    param($Definition)
+    if ($Definition.Kind -cne 'FileSystem') {throw 'Only leaf FileSystem targets are supported.'}
+    $path=Resolve-WelaSelectedSaclNativePath $Definition;Initialize-WelaFileSaclRecoveryNative
+    $target=[Wela.FileSaclRecovery.Target]::new($path)
+    try {$target.Read()} finally {$target.Dispose()}
+}
+function Get-WelaFileSaclRecoveryAddition {
+    param($Before,$After,$Ace)
+    Initialize-WelaFileSaclRecoveryNative
+    [Wela.FileSaclRecovery.Descriptor]::AddedAce($Before.DescriptorBase64,$After.DescriptorBase64,$Ace.Sid,$Ace.Mask,$Ace.Flags)
+}
+function New-WelaFileSaclRecoveryPlan {
+    param([string]$OriginalPlanPath,[string]$PendingPath,[string]$ConfirmedPath,[string]$ResultsPath)
+    $operator=Get-WelaFileSaclRecoveryOperator;$context=Get-WelaSelectedSaclContext;$sources=Get-WelaFileSaclRecoverySources
+    $files=[ordered]@{};foreach ($entry in @(@('OriginalPlan',$OriginalPlanPath),@('Pending',$PendingPath),@('Confirmed',$ConfirmedPath),@('Results',$ResultsPath))) {$files[$entry[0]]=Read-WelaFileSaclRecoveryInput $entry[1]}
+    if (@($files.Values.Path|Sort-Object -Unique).Count -ne 4) {throw 'Four distinct original evidence files are required.'}
+    $plan=$files.OriginalPlan.Data;$pending=$files.Pending.Data;$confirmed=$files.Confirmed.Data;$result=$files.Results.Data
+    Assert-WelaEvtxObject $plan @('SchemaVersion','Kind','CapturedUtc','Profile','IncludeOptional','IncludeChildren','Context','Sources','Rows','GenerationReadiness','UsableRuleCredit','Catalog','UserInventory')
+    foreach ($value in @($plan,$pending,$confirmed,$result)) {if (($value.SchemaVersion -isnot [int] -and $value.SchemaVersion -isnot [long]) -or $value.SchemaVersion -ne 1) {throw 'Unsupported original evidence schema.'}}
+    if ($plan.Kind -cne 'WelaSelectedSaclPlan' -or $plan.IncludeChildren -isnot [bool] -or $plan.IncludeChildren -or $plan.IncludeOptional -isnot [bool] -or $plan.Rows -isnot [array] -or $plan.Rows.Count -ne 1) {throw 'Require one original selected target, without child consent.'}
+    $row=$plan.Rows[0]
+    if ($row.Status -cne 'ChangeRequired' -or $row.After -or $row.DescendantsBefore -or $row.DescendantsAfter -or $row.DescendantVerification -or $row.Id -cnotmatch '^sacl-[a-f0-9]{24}$' -or $row.Definition.Kind -cne 'FileSystem' -or $row.Definition.Inheritance -cne 'None' -or $row.Definition.Propagation -cne 'None') {throw 'Original plan must describe one explicit leaf-file addition without inheritance.'}
+    Assert-WelaSelectedSaclSources $plan.Sources
+    if ($plan.Context.Key -cne $context.Key -or $plan.Context.Computer -cne $operator.Computer) {throw 'Original host context differs from the actual recovery host.'}
+    $catalog=Get-WelaSelectedSaclCatalog -Profile $plan.Profile -IncludeOptional:$plan.IncludeOptional -Context $context
+    $selected=@($catalog.Rows|Where-Object Id -CEQ $row.Id)
+    if ($selected.Count -ne 1 -or $selected[0].DefinitionKey -cne $row.DefinitionKey -or (Get-WelaSelectedSaclDefinitionKey $row.Definition) -cne $row.DefinitionKey -or (Get-WelaFileSaclRecoveryKey $selected[0].Definition) -cne (Get-WelaFileSaclRecoveryKey $row.Definition)) {throw 'Original target is not the exact currently source-bound catalog selection.'}
+    Assert-WelaFileSaclRecoverySnapshot $row.Before $row.Definition
+    $ace=Get-WelaSelectedSaclAce $row.Definition $row.Before
+    if ((Get-WelaFileSaclRecoveryKey $ace) -cne (Get-WelaFileSaclRecoveryKey $row.Ace) -or $ace.Flags -notin @(64,128,192) -or (Test-WelaSelectedSaclAce $row.Before $ace)) {throw 'Original selected audit ACE is mistyped, inherited or already covered.'}
+    $receiptFields=@('SchemaVersion','Kind','State','RecordedUtc','Computer','ContextKey','Id','Sources','Definition','Before','Ace','After','DescendantsBefore','DescendantsAfter','DescendantVerification','Ownership')
+    foreach ($receipt in @($pending,$confirmed)) {
+        Assert-WelaEvtxObject $receipt $receiptFields
+        if ($receipt.Kind -cne 'WelaSelectedSaclReceipt' -or $receipt.Computer -cne $operator.Computer -or $receipt.ContextKey -cne $context.Key -or $receipt.Id -cne $row.Id -or $receipt.DescendantsBefore -or $receipt.DescendantsAfter -or $receipt.DescendantVerification -or $receipt.Ownership -cne 'Only the verified explicit selected-root addition; never descendant ACE ownership or bulk rollback authority.') {throw 'Original receipt scope or ownership is unsupported.'}
+        Assert-WelaSelectedSaclSources $receipt.Sources
+        foreach ($name in @('Definition','Ace')) {if ((Get-WelaFileSaclRecoveryKey $receipt.$name) -cne (Get-WelaFileSaclRecoveryKey $row.$name)) {throw 'Original receipt differs from the selected plan.'}}
+        Assert-WelaFileSaclRecoverySnapshot $receipt.Before $row.Definition
+        if ((Get-WelaSelectedSaclSnapshotKey $receipt.Before) -cne (Get-WelaSelectedSaclSnapshotKey $row.Before)) {throw 'Original before-state differs across records.'}
+    }
+    if ($pending.State -cne 'Pending' -or $pending.After -or $confirmed.State -cne 'Confirmed' -or -not $confirmed.After -or $pending.RecordedUtc -cne $confirmed.RecordedUtc) {throw 'A matching pending and confirmed receipt pair is required.'}
+    Assert-WelaFileSaclRecoverySnapshot $confirmed.After $row.Definition
+    if ($confirmed.After.Identity -cne $row.Before.Identity) {throw 'The original operation changed file identity.'}
+    $added=Get-WelaFileSaclRecoveryAddition $row.Before $confirmed.After $ace
+    Assert-WelaEvtxObject $result @('SchemaVersion','Kind','ExitCode','DryRun','BackupPath','Plan','Results','GenerationReadiness','UsableRuleCredit')
+    if ($result.Kind -cne 'WelaSelectedSaclResult' -or ($result.ExitCode -isnot [int] -and $result.ExitCode -isnot [long]) -or $result.ExitCode -ne 0 -or $result.DryRun -isnot [bool] -or $result.DryRun -or $result.Results -isnot [array] -or $result.Results.Count -ne 1 -or $result.Results[0].Status -cne 'Applied') {throw 'Require a completed successful, non-dry-run selected operation.'}
+    $applied=$result.Results[0]
+    if ($result.Plan.Kind -cne 'WelaSelectedSaclPlan' -or $result.Plan.Rows -isnot [array] -or $result.Plan.Rows.Count -ne 1 -or (Get-WelaFileSaclRecoveryKey $applied) -cne (Get-WelaFileSaclRecoveryKey $result.Plan.Rows[0]) -or $applied.Id -cne $row.Id -or $applied.DefinitionKey -cne $row.DefinitionKey -or $applied.DescendantsBefore -or $applied.DescendantsAfter -or $applied.DescendantVerification) {throw 'Completed result rows or scope disagree.'}
+    foreach ($name in @('Definition','Ace')) {if ((Get-WelaFileSaclRecoveryKey $applied.$name) -cne (Get-WelaFileSaclRecoveryKey $row.$name)) {throw 'Completed selection differs from original plan.'}}
+    if ((Get-WelaSelectedSaclSnapshotKey $applied.Before) -cne (Get-WelaSelectedSaclSnapshotKey $row.Before) -or (Get-WelaSelectedSaclSnapshotKey $applied.After) -cne (Get-WelaSelectedSaclSnapshotKey $confirmed.After)) {throw 'Completed descriptor evidence disagrees.'}
+    foreach ($name in @('Profile','IncludeOptional','IncludeChildren','Context','Sources')) {if ((Get-WelaFileSaclRecoveryKey $result.Plan.$name) -cne (Get-WelaFileSaclRecoveryKey $plan.$name)) {throw 'Completed plan context differs from the original selection.'}}
+    $backup=Resolve-WelaArrivalPath $result.BackupPath
+    if ($files.Pending.Path -ine (Join-Path $backup ($row.Id+'.pending.json')) -or $files.Confirmed.Path -ine (Join-Path $backup ($row.Id+'.confirmed.json'))) {throw 'Receipt paths do not match the original recorded backup directory.'}
+    $originalTime=ConvertTo-WelaEvtxUtc $plan.CapturedUtc;$configuredTime=ConvertTo-WelaEvtxUtc $result.Plan.CapturedUtc;$receiptTime=ConvertTo-WelaEvtxUtc $pending.RecordedUtc
+    if ($originalTime -gt $configuredTime -or $configuredTime -gt $receiptTime -or $receiptTime -gt [DateTimeOffset]::UtcNow) {throw 'Original evidence timestamps are out of order or in the future.'}
+    $current=Get-WelaFileSaclRecoverySnapshot $row.Definition
+    if ((Get-WelaSelectedSaclSnapshotKey $current) -cne (Get-WelaSelectedSaclSnapshotKey $confirmed.After)) {throw 'Current file identity or descriptor differs from the completed operation; manual review required.'}
+    if ((Get-WelaSelectedSaclSnapshotKey (Get-WelaFileSaclRecoverySnapshot $row.Definition)) -cne (Get-WelaSelectedSaclSnapshotKey $current)) {throw 'File changed during recovery planning.'}
+    $inputFiles=[ordered]@{};foreach ($name in $files.Keys) {$file=$files[$name];$inputFiles[$name]=[pscustomobject]@{Path=$file.Path;Sha256=$file.Sha256;Bytes=$file.Bytes}}
+    $recovery=[pscustomobject][ordered]@{SchemaVersion=1;Kind='WelaFileSaclRecoveryPlan';Id=$row.Id;Profile=$plan.Profile;Operator=$operator;ContextKey=$context.Key;Sources=$sources;OriginalFiles=[pscustomobject]$inputFiles;Definition=$row.Definition;BeforeAddition=$row.Before;Expected=$current;AddedAce=$added;Outcome='Remove one proven explicit ordinary audit ACE; an empty present SACL can remain.';ReadyRuleCredit=0}
+    Assert-WelaFileSaclRecoveryFresh $recovery
+    $recovery
+}
+function Assert-WelaFileSaclRecoveryFresh {
+    param($Plan)
+    if ((Get-WelaFileSaclRecoveryKey (Get-WelaFileSaclRecoverySources)) -cne (Get-WelaFileSaclRecoveryKey $Plan.Sources) -or (Get-WelaFileSaclRecoveryKey (Get-WelaFileSaclRecoveryOperator)) -cne (Get-WelaFileSaclRecoveryKey $Plan.Operator) -or (Get-WelaSelectedSaclContext).Key -cne $Plan.ContextKey) {throw 'Recovery implementation, operator or host context changed.'}
+    foreach ($entry in $Plan.OriginalFiles.PSObject.Properties) {$file=Read-WelaFileSaclRecoveryInput $entry.Value.Path;if ($file.Sha256 -cne $entry.Value.Sha256 -or $file.Bytes -ne $entry.Value.Bytes) {throw 'Original recovery evidence changed.'}}
+    if ((Get-WelaSelectedSaclSnapshotKey (Get-WelaFileSaclRecoverySnapshot $Plan.Definition)) -cne (Get-WelaSelectedSaclSnapshotKey $Plan.Expected)) {throw 'Reviewed file changed before removal.'}
+}
+function Invoke-WelaFileSaclRecovery {
+    param([ValidateSet('Plan','Restore')][string]$Action='Plan',[string]$OriginalPlanPath,[string]$PendingPath,[string]$ConfirmedPath,[string]$ResultsPath,[string]$PlanPath,[string]$PlanHash,[string]$OutputPath,[switch]$Auto,[switch]$DryRun)
+    if ($Action -eq 'Plan') {
+        if ($PlanPath -or $PlanHash -or $Auto -or $DryRun -or -not $OriginalPlanPath -or -not $PendingPath -or -not $ConfirmedPath -or -not $ResultsPath -or -not $OutputPath) {throw 'Plan requires four original evidence paths and a new output directory only.'}
+        $plan=New-WelaFileSaclRecoveryPlan $OriginalPlanPath $PendingPath $ConfirmedPath $ResultsPath
+        $output=New-WelaArrivalOutput -Path $OutputPath -SourcePath (Split-Path $PSScriptRoot -Parent)
+        $artifact=Write-WelaFileSaclRecoveryArtifact $output 'plan.json' (Get-WelaFileSaclRecoveryKey $plan)
+        return [pscustomobject]@{Status='Planned';ExitCode=0;PlanPath=(Join-Path $output 'plan.json');PlanHash=$artifact.Sha256;ReadyRuleCredit=0}
+    }
+    if ($OriginalPlanPath -or $PendingPath -or $ConfirmedPath -or $ResultsPath -or -not $PlanPath -or $PlanHash -cnotmatch '^[a-f0-9]{64}$' -or ($DryRun -and ($OutputPath -or $Auto)) -or (-not $DryRun -and (-not $Auto -or -not $OutputPath))) {throw 'Restore requires PlanPath/PlanHash and either DryRun or Auto with a new output directory.'}
+    $reviewed=Read-WelaFileSaclRecoveryInput $PlanPath
+    if ($reviewed.Sha256 -cne $PlanHash -or $reviewed.Data.Kind -cne 'WelaFileSaclRecoveryPlan') {throw 'Reviewed recovery plan hash or kind differs.'}
+    $plan=$reviewed.Data;$inputs=$plan.OriginalFiles
+    $rebuilt=New-WelaFileSaclRecoveryPlan $inputs.OriginalPlan.Path $inputs.Pending.Path $inputs.Confirmed.Path $inputs.Results.Path
+    if ((Get-WelaFileSaclRecoveryKey $plan) -cne (Get-WelaFileSaclRecoveryKey $rebuilt)) {throw 'Reviewed recovery plan is stale or modified.'}
+    if ($DryRun) {return [pscustomobject]@{Status='WouldRemoveAddedAce';ExitCode=0;Target=$plan.Definition.Path;ReadyRuleCredit=0}}
+    $output=New-WelaArrivalOutput -Path $OutputPath -SourcePath (Split-Path $reviewed.Path -Parent)
+    $report=[pscustomobject][ordered]@{SchemaVersion=1;Kind='WelaFileSaclRecoveryResult';Status='Refused';ExitCode=1;StartedUtc=[DateTime]::UtcNow.ToString('o');CompletedUtc=$null;PlanHash=$PlanHash;Before=$plan.Expected;After=$null;WriteAttempted=$false;Artifacts=@();OriginalDescriptorBytesMatch=$false;Diagnostic='';OutputPath=$output;ReadyRuleCredit=0;PolicyChanges=0;Scope='Remove only one proven explicit leaf-file audit ACE; preserve other ACE bytes/counts and observed descriptor components. No descendant, exact historical descriptor, event or Sigma claim.'}
+    $target=$null
+    try {
+        $report.Artifacts+=Write-WelaFileSaclRecoveryArtifact $output 'reviewed-plan.json' (Get-WelaFileSaclRecoveryKey $plan)
+        $report.Artifacts+=Write-WelaFileSaclRecoveryArtifact $output 'pending.json' (Get-WelaFileSaclRecoveryKey ([pscustomobject]@{Kind='WelaFileSaclRecoveryIntent';PlanHash=$PlanHash;Before=$plan.Expected;RemoveAce=$plan.AddedAce;RecordedUtc=[DateTime]::UtcNow.ToString('o')}))
+        Assert-WelaFileSaclRecoveryFresh $plan
+        if ((Read-WelaFileSaclRecoveryInput $reviewed.Path).Sha256 -cne $PlanHash) {throw 'Reviewed recovery plan changed before write.'}
+        Initialize-WelaFileSaclRecoveryNative
+        $target=[Wela.FileSaclRecovery.Target]::new((Resolve-WelaSelectedSaclNativePath $plan.Definition))
+        try {$report.After=$target.Remove($plan.Expected.Identity,$plan.Expected.DescriptorBase64,$plan.AddedAce)} finally {$report.WriteAttempted=$target.WriteAttempted}
+        $target.Dispose();$target=$null
+        $fresh=Get-WelaFileSaclRecoverySnapshot $plan.Definition
+        if ((Get-WelaSelectedSaclSnapshotKey $fresh) -cne (Get-WelaSelectedSaclSnapshotKey $report.After)) {throw 'File identity or descriptor changed after removal.'}
+        if ((Get-WelaFileSaclRecoveryKey (Get-WelaFileSaclRecoverySources)) -cne (Get-WelaFileSaclRecoveryKey $plan.Sources) -or (Get-WelaFileSaclRecoveryKey (Get-WelaFileSaclRecoveryOperator)) -cne (Get-WelaFileSaclRecoveryKey $plan.Operator) -or (Get-WelaSelectedSaclContext).Key -cne $plan.ContextKey) {throw 'Recovery context changed after removal.'}
+        foreach ($entry in $plan.OriginalFiles.PSObject.Properties) {if ((Read-WelaFileSaclRecoveryInput $entry.Value.Path).Sha256 -cne $entry.Value.Sha256) {throw 'Original recovery evidence changed after removal.'}}
+        if ((Read-WelaFileSaclRecoveryInput $reviewed.Path).Sha256 -cne $PlanHash) {throw 'Reviewed plan changed after removal.'}
+        foreach ($artifact in $report.Artifacts) {if ((Get-FileHash -LiteralPath (Join-Path $output $artifact.Name) -Algorithm SHA256).Hash.ToLowerInvariant() -cne $artifact.Sha256) {throw 'Recovery artifact changed after writing.'}}
+        if ((Get-WelaSelectedSaclSnapshotKey (Get-WelaFileSaclRecoverySnapshot $plan.Definition)) -cne (Get-WelaSelectedSaclSnapshotKey $report.After)) {throw 'Final reopened file differs after recovery.'}
+        $report.OriginalDescriptorBytesMatch=$report.After.DescriptorBase64 -ceq $plan.BeforeAddition.DescriptorBase64
+        $report.Status='AddedAceRemoved';$report.ExitCode=0
+    } catch {$report.Diagnostic=$_.Exception.Message;if ($report.WriteAttempted) {$report.Status='WriteAttemptedUnverified'}}
+    finally {if ($target) {try {$target.Dispose()} catch {$report.Status='WriteAttemptedUnverified';$report.ExitCode=1;$report.Diagnostic+=' Native cleanup failed: '+$_.Exception.Message}}}
+    $report.CompletedUtc=[DateTime]::UtcNow.ToString('o')
+    $null=Write-WelaFileSaclRecoveryArtifact $output 'result.json' (Get-WelaFileSaclRecoveryKey $report)
+    $report
+}
+
+function Write-WelaFileSaclRecoveryArtifact {
+    param([string]$Root,[string]$Name,[string]$Text)
+    $null=Resolve-WelaArrivalPath $Root
+    $bytes=[Text.UTF8Encoding]::new($false).GetBytes($Text);$path=Join-Path $Root $Name
+    $stream=[IO.File]::Open($path,[IO.FileMode]::CreateNew,[IO.FileAccess]::Write,[IO.FileShare]::None)
+    try {$stream.Write($bytes,0,$bytes.Length);$stream.Flush($true)} finally {$stream.Dispose()}
+    $hash=Get-WelaArrivalHash $bytes
+    if ((Get-FileHash -LiteralPath $path -Algorithm SHA256 -ErrorAction Stop).Hash.ToLowerInvariant() -cne $hash) {throw 'Recovery artifact readback differs.'}
+    [pscustomobject]@{Name=$Name;Sha256=$hash;Bytes=$bytes.Length}
+}

scripts/FileSaclRecoveryNative.cs

@@ -0,0 +1,110 @@
+// Narrow leaf-file recovery: remove one proven explicit ordinary audit ACE.
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Runtime.InteropServices;
+using System.Security.AccessControl;
+using System.Security.Principal;
+using System.Text;
+namespace Wela.FileSaclRecovery {
+ public sealed class Ace { public string Binary; public int Type,Flags,Mask; public string Sid; public bool Ordinary; }
+ public sealed class Snapshot {
+  public string Path,Kind,Identity; public bool IsDirectory;
+  public string DescriptorBase64,Owner,Group,DaclBase64; public int ControlFlags,SecurityInformation;
+  public string DescriptorScope; public Ace[] Aces;
+ }
+ public static class Descriptor {
+  public const string SourceSha256="__WELA_FILE_SACL_RECOVERY_SOURCE_SHA256__";
+  public static string Bytes(GenericAcl value) { if(value==null)return null;byte[] b=new byte[value.BinaryLength];value.GetBinaryForm(b,0);return Convert.ToBase64String(b); }
+  public static string Bytes(GenericAce value) { byte[] b=new byte[value.BinaryLength];value.GetBinaryForm(b,0);return Convert.ToBase64String(b); }
+  static string Sid(SecurityIdentifier value) {return value==null?null:value.Value;}
+  public static RawSecurityDescriptor Parse(string value) {
+   byte[] b=Convert.FromBase64String(value);
+   if(b.Length<20||b.Length>1048576||Convert.ToBase64String(b)!=value)throw new InvalidOperationException("Invalid or noncanonical descriptor bytes.");
+   RawSecurityDescriptor sd=new RawSecurityDescriptor(b,0);
+   return sd;
+  }
+  static Dictionary<string,int> Counts(RawAcl acl) {
+   Dictionary<string,int> counts=new Dictionary<string,int>(StringComparer.Ordinal);
+   if(acl!=null)foreach(GenericAce ace in acl){string b=Bytes(ace);if(!counts.ContainsKey(b))counts[b]=0;counts[b]++;}
+   return counts;
+  }
+  static void Outside(RawSecurityDescriptor before,RawSecurityDescriptor after,bool allowPresence) {
+   int mask=allowPresence?~16:~0;
+   if(Sid(before.Owner)!=Sid(after.Owner)||Sid(before.Group)!=Sid(after.Group)||Bytes(before.DiscretionaryAcl)!=Bytes(after.DiscretionaryAcl)||before.ResourceManagerControl!=after.ResourceManagerControl||(((int)before.ControlFlags)&mask)!=(((int)after.ControlFlags)&mask))throw new InvalidOperationException("Owner, group, DACL or preserved control/header fields differ.");
+  }
+  public static string AddedAce(string beforeBytes,string afterBytes,string sid,int mask,int flags) {
+   if((sid!="S-1-1-0"&&sid!="S-1-5-11")||mask<=0||(flags!=64&&flags!=128&&flags!=192))throw new InvalidOperationException("Only an explicit ordinary non-inherited selected audit ACE is supported.");
+   RawSecurityDescriptor before=Parse(beforeBytes),after=Parse(afterBytes);Outside(before,after,true);
+   if(after.SystemAcl==null||after.SystemAcl.Revision!=(before.SystemAcl==null?2:before.SystemAcl.Revision))throw new InvalidOperationException("SACL revision changed during the claimed addition.");
+   if(before.SystemAcl!=null)foreach(GenericAce entry in before.SystemAcl){CommonAce common=entry as CommonAce;if(common!=null&&!common.IsCallback&&common.AceType==AceType.SystemAudit&&common.SecurityIdentifier.Value==sid&&(int)common.AceFlags==flags&&(common.AccessMask&mask)==mask)throw new InvalidOperationException("Original descriptor already covered the requested audit ACE.");}
+   string added=Bytes(new CommonAce((AceFlags)flags,AceQualifier.SystemAudit,mask,new SecurityIdentifier(sid),false,null));
+   Dictionary<string,int> remaining=Counts(after.SystemAcl);
+   if(!remaining.ContainsKey(added)||remaining[added]!=1)throw new InvalidOperationException("Expected exactly one new matching audit ACE.");
+   remaining[added]--;
+   if(before.SystemAcl!=null)foreach(GenericAce entry in before.SystemAcl){string b=Bytes(entry);if(!remaining.ContainsKey(b)||remaining[b]<1)throw new InvalidOperationException("An original ACE was changed or removed.");remaining[b]--;}
+   foreach(int count in remaining.Values)if(count!=0)throw new InvalidOperationException("The completed operation changed more than one audit ACE.");
+   return added;
+  }
+  public static void Removed(string beforeBytes,string afterBytes,string added) {
+   RawSecurityDescriptor before=Parse(beforeBytes),after=Parse(afterBytes);Outside(before,after,false);
+   if(before.SystemAcl==null||after.SystemAcl==null||before.SystemAcl.Revision!=after.SystemAcl.Revision)throw new InvalidOperationException("SACL revision or presence changed during removal.");
+   Dictionary<string,int> expected=Counts(before.SystemAcl),actual=Counts(after.SystemAcl);
+   if(!expected.ContainsKey(added)||expected[added]!=1)throw new InvalidOperationException("The selected audit ACE is no longer unique.");
+   expected[added]--;
+   foreach(KeyValuePair<string,int> entry in expected){int count=actual.ContainsKey(entry.Key)?actual[entry.Key]:0;if(count!=entry.Value)throw new InvalidOperationException("Unrelated audit ACEs changed during removal.");actual.Remove(entry.Key);}
+   if(actual.Count!=0)throw new InvalidOperationException("Unexpected ACE appeared during removal.");
+  }
+  public static Snapshot Observe(string path,string identity,byte[] bytes) {
+   string encoded=Convert.ToBase64String(bytes);RawSecurityDescriptor sd=Parse(encoded);List<Ace> entries=new List<Ace>();
+   if(sd.SystemAcl!=null)foreach(GenericAce ace in sd.SystemAcl){CommonAce common=ace as CommonAce;bool ordinary=common!=null&&!common.IsCallback&&common.AceType==AceType.SystemAudit;entries.Add(new Ace {Binary=Bytes(ace),Type=(int)ace.AceType,Flags=(int)ace.AceFlags,Mask=ordinary?common.AccessMask:0,Sid=ordinary?common.SecurityIdentifier.Value:null,Ordinary=ordinary});}
+   return new Snapshot {Path=path,Kind="FileSystem",Identity=identity,IsDirectory=false,DescriptorBase64=encoded,Owner=Sid(sd.Owner),Group=Sid(sd.Group),DaclBase64=Bytes(sd.DiscretionaryAcl),ControlFlags=(int)sd.ControlFlags,SecurityInformation=511,DescriptorScope="WinSDK-defined sections 0x1ff; future sections unobserved",Aces=entries.ToArray()};
+  }
+ }
+ sealed class Privilege : IDisposable {
+  [StructLayout(LayoutKind.Sequential)] struct Luid {public uint Low;public int High;}
+  [StructLayout(LayoutKind.Sequential)] struct TokenPrivileges {public uint Count;public Luid Luid;public uint Attributes;}
+  [DllImport("kernel32.dll")] static extern IntPtr GetCurrentProcess();
+  [DllImport("kernel32.dll")] static extern IntPtr GetCurrentThread();
+  [DllImport("kernel32.dll",SetLastError=true)] static extern bool CloseHandle(IntPtr value);
+  [DllImport("advapi32.dll",SetLastError=true)] static extern bool OpenProcessToken(IntPtr process,uint access,out IntPtr token);
+  [DllImport("advapi32.dll",SetLastError=true)] static extern bool OpenThreadToken(IntPtr thread,uint access,bool self,out IntPtr token);
+  [DllImport("advapi32.dll",CharSet=CharSet.Unicode,SetLastError=true)] static extern bool LookupPrivilegeValue(string system,string name,out Luid luid);
+  [DllImport("advapi32.dll",SetLastError=true)] static extern bool AdjustTokenPrivileges(IntPtr token,bool disable,ref TokenPrivileges value,uint size,out TokenPrivileges previous,out uint required);
+  IntPtr token;TokenPrivileges previous;
+  public Privilege(){IntPtr thread;
+   if(OpenThreadToken(GetCurrentThread(),8,true,out thread)){CloseHandle(thread);throw new InvalidOperationException("Impersonated recovery is unsupported.");}
+   int error=Marshal.GetLastWin32Error();if(error!=1008)throw new Win32Exception(error);
+   if(!OpenProcessToken(GetCurrentProcess(),0x28,out token))throw new Win32Exception(Marshal.GetLastWin32Error());
+   try{Luid luid;if(!LookupPrivilegeValue(null,"SeSecurityPrivilege",out luid))throw new Win32Exception(Marshal.GetLastWin32Error());TokenPrivileges request=new TokenPrivileges {Count=1,Luid=luid,Attributes=2};uint required;bool ok=AdjustTokenPrivileges(token,false,ref request,(uint)Marshal.SizeOf(typeof(TokenPrivileges)),out previous,out required);error=Marshal.GetLastWin32Error();if(!ok||error!=0)throw new Win32Exception(error,"SeSecurityPrivilege is unavailable.");}
+   catch{CloseHandle(token);token=IntPtr.Zero;throw;}
+  }
+  public void Dispose(){if(token==IntPtr.Zero)return;try{TokenPrivileges ignored;uint required;bool ok=AdjustTokenPrivileges(token,false,ref previous,(uint)Marshal.SizeOf(typeof(TokenPrivileges)),out ignored,out required);int error=Marshal.GetLastWin32Error();if(!ok||error!=0)throw new Win32Exception(error,"SeSecurityPrivilege restoration failed.");}finally{CloseHandle(token);token=IntPtr.Zero;}}
+ }
+ public sealed class Target : IDisposable {
+  [StructLayout(LayoutKind.Sequential,Pack=4)] struct FileInfo {public uint Attributes;public long Created,Accessed,Written;public uint Volume,SizeHigh,SizeLow,Links,IndexHigh,IndexLow;}
+  [DllImport("kernel32.dll",CharSet=CharSet.Unicode,SetLastError=true)] static extern IntPtr CreateFile(string name,uint access,uint share,IntPtr security,uint disposition,uint flags,IntPtr template);
+  [DllImport("kernel32.dll",SetLastError=true)] static extern bool CloseHandle(IntPtr handle);
+  [DllImport("kernel32.dll",SetLastError=true)] static extern bool GetFileInformationByHandle(IntPtr handle,out FileInfo info);
+  [DllImport("kernel32.dll",CharSet=CharSet.Unicode,SetLastError=true)] static extern uint GetFinalPathNameByHandle(IntPtr handle,StringBuilder path,uint size,uint flags);
+  [DllImport("kernel32.dll")] static extern IntPtr LocalFree(IntPtr value);
+  [DllImport("advapi32.dll")] static extern uint GetSecurityInfo(IntPtr handle,uint kind,uint flags,out IntPtr owner,out IntPtr group,out IntPtr dacl,out IntPtr sacl,out IntPtr descriptor);
+  [DllImport("advapi32.dll")] static extern uint GetSecurityDescriptorLength(IntPtr descriptor);
+  [DllImport("advapi32.dll")] static extern uint SetSecurityInfo(IntPtr handle,uint kind,uint flags,IntPtr owner,IntPtr group,IntPtr dacl,IntPtr sacl);
+  readonly string path;IntPtr handle;Privilege privilege;public bool WriteAttempted {get;private set;}
+  public Target(string path){this.path=path;try{privilege=new Privilege();handle=CreateFile(path,0x01020000,3,IntPtr.Zero,3,0x02200000,IntPtr.Zero);if(handle==new IntPtr(-1)){int error=Marshal.GetLastWin32Error();handle=IntPtr.Zero;throw new Win32Exception(error);}Check();}catch{Dispose();throw;}}
+  string Check(){if(handle==IntPtr.Zero)throw new ObjectDisposedException("Target");FileInfo info;if(!GetFileInformationByHandle(handle,out info))throw new Win32Exception(Marshal.GetLastWin32Error());if((info.Attributes&0x410)!=0)throw new InvalidOperationException("Directories and reparse files are unsupported.");StringBuilder final=new StringBuilder(32768);uint length=GetFinalPathNameByHandle(handle,final,(uint)final.Capacity,0);if(length==0||length>=final.Capacity||!String.Equals(final.ToString(),"\\\\?\\"+path,StringComparison.OrdinalIgnoreCase))throw new InvalidOperationException("Final held file path differs from the reviewed path.");return info.Volume+":"+info.IndexHigh+":"+info.IndexLow+":"+info.Created;}
+  public Snapshot Read(){string identity=Check();IntPtr owner,group,dacl,sacl,descriptor;uint error=GetSecurityInfo(handle,1,511,out owner,out group,out dacl,out sacl,out descriptor);if(error!=0)throw new Win32Exception((int)error,"Full SDK-defined file descriptor read failed.");byte[] bytes;try{uint size=GetSecurityDescriptorLength(descriptor);if(size<20||size>1048576)throw new InvalidOperationException("Invalid descriptor size.");bytes=new byte[size];Marshal.Copy(descriptor,bytes,0,(int)size);}finally{LocalFree(descriptor);}if(Check()!=identity)throw new InvalidOperationException("Held file identity changed.");return Descriptor.Observe(path,identity,bytes);}
+  public Snapshot Remove(string expectedIdentity,string expectedDescriptor,string added){
+   Snapshot before=Read();if(before.Identity!=expectedIdentity||before.DescriptorBase64!=expectedDescriptor)throw new InvalidOperationException("Reviewed file identity or descriptor changed before removal.");
+   RawSecurityDescriptor sd=Descriptor.Parse(before.DescriptorBase64);int index=-1;
+   if(sd.SystemAcl!=null)for(int i=0;i<sd.SystemAcl.Count;i++)if(Descriptor.Bytes(sd.SystemAcl[i])==added){if(index!=-1)throw new InvalidOperationException("Audit ACE is not unique.");index=i;}
+   if(index<0)throw new InvalidOperationException("Audit ACE is absent.");CommonAce ace=sd.SystemAcl[index] as CommonAce;
+   if(ace==null||ace.IsCallback||ace.AceType!=AceType.SystemAudit||((int)ace.AceFlags!=64&&(int)ace.AceFlags!=128&&(int)ace.AceFlags!=192))throw new InvalidOperationException("Only an explicit ordinary audit ACE can be removed.");
+   sd.SystemAcl.RemoveAce(index);byte[] bytes=new byte[sd.SystemAcl.BinaryLength];sd.SystemAcl.GetBinaryForm(bytes,0);IntPtr buffer=Marshal.AllocHGlobal(bytes.Length);
+   try{Marshal.Copy(bytes,0,buffer,bytes.Length);WriteAttempted=true;uint error=SetSecurityInfo(handle,1,8,IntPtr.Zero,IntPtr.Zero,IntPtr.Zero,buffer);if(error!=0)throw new Win32Exception((int)error,"SACL-only removal failed.");}finally{Marshal.FreeHGlobal(buffer);}
+   Snapshot after=Read();if(after.Identity!=before.Identity)throw new InvalidOperationException("File identity changed during removal.");Descriptor.Removed(before.DescriptorBase64,after.DescriptorBase64,added);return after;
+  }
+  public void Dispose(){try{if(handle!=IntPtr.Zero){CloseHandle(handle);handle=IntPtr.Zero;}}finally{if(privilege!=null){privilege.Dispose();privilege=null;}}}
+ }
+}