stop on BITS download errors

reject 0 byte dsa-collector.exe before launching
2026-09-30 09:46:37 -04:00
parent 35c1904d0d
commit 4e6c35a8f4
6 changed files with 119 additions and 5 deletions
@@ -0,0 +1,64 @@
+#Requires -Version 5.0
+# Offline regression tests. BITS and URL resolution are mocked.
+$ErrorActionPreference = 'Stop'
+$DownloadToolsPath = Join-Path (Split-Path $PSScriptRoot -Parent) 'Tools.ps1'
+$DownloadTokens = $null
+$DownloadParseErrors = $null
+$DownloadAst = [Management.Automation.Language.Parser]::ParseFile($DownloadToolsPath, [ref]$DownloadTokens, [ref]$DownloadParseErrors)
+If ($DownloadParseErrors.Count) { Throw ($DownloadParseErrors | Out-String) }
+$DownloadDefinition = $DownloadAst.Find({
+    param($Node)
+    $Node -is [Management.Automation.Language.FunctionDefinitionAst] -and $Node.Name -eq 'Download-File'
+}, $true)
+. ([scriptblock]::Create($DownloadDefinition.Extent.Text))
+
+Function Get-AbsoluteURI { param($URL) Return $URL }
+Function Start-BitsTransfer {
+    [CmdletBinding()]
+    param($Source, $Destination)
+    If ($script:DownloadTestMode -eq 'success') {
+        [IO.File]::WriteAllText($Destination, 'Synthetic download.')
+        Return
+    }
+    [IO.File]::WriteAllBytes($Destination, [byte[]]@())
+    If ($script:DownloadTestMode -eq 'terminating-error') { Throw 'Synthetic BITS connection failure.' }
+    Microsoft.PowerShell.Utility\Write-Error 'Synthetic BITS TLS failure.'
+}
+
+$DownloadTestRoot = Join-Path ([IO.Path]::GetTempPath()) ('download-file-tests-' + [guid]::NewGuid().ToString('N'))
+$null = New-Item -Path $DownloadTestRoot -ItemType Directory
+Try {
+    $DownloadTestFile = Join-Path $DownloadTestRoot 'collector $test.exe'
+    $script:DownloadTestMode = 'success'
+    $DownloadResult = Download-File -URL 'https://example.invalid/collector.exe' -File $DownloadTestFile
+    If ($DownloadResult -cne $DownloadTestFile -or [IO.File]::ReadAllText($DownloadResult) -cne 'Synthetic download.') {
+        Throw 'Successful download did not return the completed file.'
+    }
+    Write-Host 'PASS: successful download returns its destination.'
+
+    Foreach ($script:DownloadTestMode in @('nonterminating-error','terminating-error')) {
+        # Match an RMM that uses the normal Continue preference and does not pass -ErrorAction.
+        $ErrorActionPreference = 'Continue'
+        $DownloadCaught = $null
+        $DownloadReturnedPaths = @()
+        Try {
+            Download-File -URL 'https://example.invalid/collector.exe' -File $DownloadTestFile |
+                ForEach-Object { $DownloadReturnedPaths += $_ }
+        }
+        Catch { $DownloadCaught = $_ }
+        Finally { $ErrorActionPreference = 'Stop' }
+        If ($null -eq $DownloadCaught -or $DownloadCaught.Exception.Message -notlike '*Synthetic BITS*failure*') {
+            Throw 'Failed transfer must throw and preserve the BITS error.'
+        }
+        If ($DownloadReturnedPaths.Count -ne 0) { Throw 'Failed transfer returned a success path.' }
+        Write-Host "PASS: $script:DownloadTestMode stops the caller and preserves the transfer error."
+    }
+    Write-Host "All Download-File tests passed on PowerShell $($PSVersionTable.PSVersion), $([IntPtr]::Size * 8)-bit."
+}
+Finally {
+    $DownloadResolvedRoot = (Resolve-Path -LiteralPath $DownloadTestRoot).Path
+    $DownloadTempRoot = [IO.Path]::GetFullPath([IO.Path]::GetTempPath()).TrimEnd('\') + '\'
+    If (!$DownloadResolvedRoot.StartsWith($DownloadTempRoot, [StringComparison]::OrdinalIgnoreCase) -or
+        (Split-Path $DownloadResolvedRoot -Leaf) -notlike 'download-file-tests-*') { Throw 'Unexpected cleanup directory.' }
+    Remove-Item -LiteralPath $DownloadResolvedRoot -Recurse -Force
+}