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| 1 | +##Documentation for Customized Rules in PowerShell Scripts |
| 2 | +PSScriptAnalyzer uses MEF(Managed Extensibility Framework) to import all rules defined in the assembly. It can also consume rules written in PowerShell scripts. When calling Invoke-ScriptAnalyzer, users can pass customized rules using parameter -CustomizedRulePath to apply rule checkings on the scripts. |
| 3 | + |
| 4 | +This documentation serves as a basic guideline on how to define customized rules. |
| 5 | + |
| 6 | +###Basics |
| 7 | +- Functions should have comment-based help. Make sure .DESCRIPTION field is there, as it will be consumed as rule description for the customized rule. |
| 8 | +``` |
| 9 | +<# |
| 10 | +.SYNOPSIS |
| 11 | + Name of your rule. |
| 12 | +.DESCRIPTION |
| 13 | + This would be the description of your rule. Please refer to Rule Documentation for consistent rule messages. |
| 14 | +.EXAMPLE |
| 15 | +.INPUTS |
| 16 | +.OUTPUTS |
| 17 | +.NOTES |
| 18 | +#> |
| 19 | +``` |
| 20 | + |
| 21 | +- Output type should be DiagnosticRecord: |
| 22 | +``` |
| 23 | +[OutputType([Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]])] |
| 24 | +``` |
| 25 | + |
| 26 | +- Make sure each function takes either a Token or an Ast as a parameter |
| 27 | +``` |
| 28 | +Param |
| 29 | + ( |
| 30 | + [Parameter(Mandatory = $true)] |
| 31 | + [ValidateNotNullOrEmpty()] |
| 32 | + [System.Management.Automation.Language.ScriptBlockAst] |
| 33 | + $testAst |
| 34 | + ) |
| 35 | +``` |
| 36 | + |
| 37 | +- DiagnosticRecord should have four properties: Message, Extent, RuleName and Severity |
| 38 | +``` |
| 39 | +$result = [Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]]@{"Message" = "This is a sample rule"; |
| 40 | + "Extent" = $ast.Extent; |
| 41 | + "RuleName" = $PSCmdlet.MyInvocation.InvocationName; |
| 42 | + "Severity" = "Warning"} |
| 43 | +``` |
| 44 | + |
| 45 | +- Make sure you export the function(s) at the end of the script using Export-ModuleMember |
| 46 | +``` |
| 47 | +Export-ModuleMember -Function (FunctionName) |
| 48 | +``` |
| 49 | + |
| 50 | +###Example |
| 51 | +``` |
| 52 | +<# |
| 53 | +.SYNOPSIS |
| 54 | + Uses #Requires -RunAsAdministrator instead of your own methods. |
| 55 | +.DESCRIPTION |
| 56 | + The #Requires statement prevents a script from running unless the Windows PowerShell version, modules, snap-ins, and module and snap-in version prerequisites are met. |
| 57 | + From Windows PowerShell 4.0, the #Requires statement let script developers require that sessions be run with elevated user rights (run as Administrator). |
| 58 | + Script developers does not need to write their own methods any more. |
| 59 | + To fix a violation of this rule, please consider to use #Requires -RunAsAdministrator instead of your own methods. |
| 60 | +.EXAMPLE |
| 61 | + Measure-RequiresRunAsAdministrator -ScriptBlockAst $ScriptBlockAst |
| 62 | +.INPUTS |
| 63 | + [System.Management.Automation.Language.ScriptBlockAst] |
| 64 | +.OUTPUTS |
| 65 | + [Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]] |
| 66 | +.NOTES |
| 67 | + None |
| 68 | +#> |
| 69 | +function Measure-RequiresRunAsAdministrator |
| 70 | +{ |
| 71 | + [CmdletBinding()] |
| 72 | + [OutputType([Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord[]])] |
| 73 | + Param |
| 74 | + ( |
| 75 | + [Parameter(Mandatory = $true)] |
| 76 | + [ValidateNotNullOrEmpty()] |
| 77 | + [System.Management.Automation.Language.ScriptBlockAst] |
| 78 | + $ScriptBlockAst |
| 79 | + ) |
| 80 | +
|
| 81 | + Process |
| 82 | + { |
| 83 | + $results = @() |
| 84 | + try |
| 85 | + { |
| 86 | + #region Define predicates to find ASTs. |
| 87 | + # Finds specific method, IsInRole. |
| 88 | + [ScriptBlock]$predicate1 = { |
| 89 | + param ([System.Management.Automation.Language.Ast]$Ast) |
| 90 | + [bool]$returnValue = $false |
| 91 | + if ($Ast -is [System.Management.Automation.Language.MemberExpressionAst]) |
| 92 | + { |
| 93 | + [System.Management.Automation.Language.MemberExpressionAst]$meAst = $ast; |
| 94 | + if ($meAst.Member -is [System.Management.Automation.Language.StringConstantExpressionAst]) |
| 95 | + { |
| 96 | + [System.Management.Automation.Language.StringConstantExpressionAst]$sceAst = $meAst.Member; |
| 97 | + if ($sceAst.Value -eq "isinrole") |
| 98 | + { |
| 99 | + $returnValue = $true; |
| 100 | + } |
| 101 | + } |
| 102 | + } |
| 103 | + return $returnValue |
| 104 | + } |
| 105 | +
|
| 106 | + # Finds specific value, [system.security.principal.windowsbuiltinrole]::administrator. |
| 107 | + [ScriptBlock]$predicate2 = { |
| 108 | + param ([System.Management.Automation.Language.Ast]$Ast) |
| 109 | + [bool]$returnValue = $false |
| 110 | + if ($ast -is [System.Management.Automation.Language.AssignmentStatementAst]) |
| 111 | + { |
| 112 | + [System.Management.Automation.Language.AssignmentStatementAst]$asAst = $Ast; |
| 113 | + if ($asAst.Right.ToString().ToLower() -eq "[system.security.principal.windowsbuiltinrole]::administrator") |
| 114 | + { |
| 115 | + $returnValue = $true |
| 116 | + } |
| 117 | + } |
| 118 | + return $returnValue |
| 119 | + } |
| 120 | + #endregion |
| 121 | + #region Finds ASTs that match the predicates. |
| 122 | + |
| 123 | + [System.Management.Automation.Language.Ast[]]$methodAst = $ScriptBlockAst.FindAll($predicate1, $true) |
| 124 | + [System.Management.Automation.Language.Ast[]]$assignmentAst = $ScriptBlockAst.FindAll($predicate2, $true) |
| 125 | + if ($null -ne $ScriptBlockAst.ScriptRequirements) |
| 126 | + { |
| 127 | + if ((!$ScriptBlockAst.ScriptRequirements.IsElevationRequired) -and |
| 128 | + ($methodAst.Count -ne 0) -and ($assignmentAst.Count -ne 0)) |
| 129 | + { |
| 130 | + $result = [Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord]@{"Message" = $Messages.MeasureRequiresRunAsAdministrator; |
| 131 | + "Extent" = $assignmentAst.Extent; |
| 132 | + "RuleName" = $PSCmdlet.MyInvocation.InvocationName; |
| 133 | + "Severity" = "Information"} |
| 134 | + $results += $result |
| 135 | + } |
| 136 | + } |
| 137 | + else |
| 138 | + { |
| 139 | + if (($methodAst.Count -ne 0) -and ($assignmentAst.Count -ne 0)) |
| 140 | + { |
| 141 | + $result = [Microsoft.Windows.Powershell.ScriptAnalyzer.Generic.DiagnosticRecord]@{"Message" = $Messages.MeasureRequiresRunAsAdministrator; |
| 142 | + "Extent" = $assignmentAst.Extent; |
| 143 | + "RuleName" = $PSCmdlet.MyInvocation.InvocationName; |
| 144 | + "Severity" = "Information"} |
| 145 | + $results += $result |
| 146 | + } |
| 147 | + } |
| 148 | + return $results |
| 149 | + #endregion |
| 150 | + } |
| 151 | + catch |
| 152 | + { |
| 153 | + $PSCmdlet.ThrowTerminatingError($PSItem) |
| 154 | + } |
| 155 | + } |
| 156 | +} |
| 157 | +``` |
| 158 | +More examples can be found in *Tests\Engine\CommunityRules* |
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