Merge pull request #125 from microsoft/global-parameters

PS: Global parameter support

powershell/ql/lib/semmle/code/powershell/Function.qll

@@ -69,6 +69,8 @@ abstract private class AbstractFunction extends Ast {
   EntryBasicBlock getEntryBasicBlock() { result.getScope() = this.getBody() }
 }
 
+final class Function = AbstractFunction;
+
 /**
  * A function definition.
  */
@@ -114,4 +116,12 @@ class Constructor extends Method {
   Constructor() { this.isConstructor() }
 }
 
-final class Function = FunctionBase;
+class TopLevel extends AbstractFunction instanceof TopLevelScriptBlock {
+  final override string getName() { result = "toplevel" }
+
+  final override ScriptBlock getBody() { result = this }
+
+  final override Parameter getFunctionParameter(int i) { none() }
+
+  final override Type getDeclaringType() { none() }
+}

powershell/ql/lib/semmle/code/powershell/ScriptBlock.qll

@@ -10,7 +10,7 @@ class ScriptBlock extends @script_block, Ast {
     else result = "{...}"
   }
 
-  override SourceLocation getLocation() { script_block_location(this, result) }
+  override Location getLocation() { script_block_location(this, result) }
 
   int getNumUsings() { script_block(this, result, _, _, _, _) }
 
@@ -51,6 +51,42 @@ class ScriptBlock extends @script_block, Ast {
   ModuleSpecification getAModuleSpecification() { result = this.getModuleSpecification(_) }
 
   final override Scope getEnclosingScope() { result = this }
+
+  /**
+   * Gets the `i`'th paramter in this scope.
+   *
+   * This may be both function paramters and parameter block parameters.
+   */
+  Parameter getParameter(int i) {
+    exists(Function func |
+      func.getBody() = this and
+      result = func.getParameter(i)
+    )
+    or
+    this.isTopLevel() and
+    result = this.getParamBlock().getParameter(i)
+  }
+
+  /**
+   * Gets a paramter in this scope.
+   *
+   * This may be both function parameters and parameter block parameters.
+   */
+  Parameter getAParameter() { result = this.getParameter(_) }
+
+  Parameter getThisParameter() {
+    exists(Function func |
+      func.getBody() = this and
+      result = func.getThisParameter()
+    )
+  }
+
+  /** Gets the number of function parameters. */
+  final int getNumberOfParameters() { result = count(this.getAParameter()) }
+
+  final Parameter getParameterExcludingPiplines(int i) {
+    result = this.getParamBlock().getParameterExcludingPiplines(i)
+  }
 }
 
 /** A `process` block. */
@@ -69,3 +105,7 @@ class ProcessBlock extends NamedBlock {
     result = scriptBlock.getEnclosingFunction().getAParameter()
   }
 }
+
+class TopLevelScriptBlock extends ScriptBlock {
+  TopLevelScriptBlock() { this.isTopLevel() }
+}

powershell/ql/lib/semmle/code/powershell/controlflow/internal/Scope.qll

@@ -14,33 +14,7 @@ Scope scopeOf(Ast n) {
  * A variable scope. This is either a top-level (file), a module, a class,
  * or a callable.
  */
-class Scope extends Ast, @script_block {
+class Scope extends Ast, ScriptBlock {
   /** Gets the outer scope, if any. */
   Scope getOuterScope() { result = scopeOf(this) }
-
-  /**
-   * Gets the `i`'th paramter in this scope.
-   *
-   * This may be both function paramters and parameter block parameters.
-   */
-  Parameter getParameter(int i) {
-    exists(Function func |
-      func.getBody() = this and
-      result = func.getParameter(i)
-    )
-  }
-
-  /**
-   * Gets a paramter in this scope.
-   *
-   * This may be both function paramters and parameter block parameters.
-   */
-  Parameter getAParameter() { result = this.getParameter(_) }
-
-  Parameter getThisParameter() {
-    exists(Function func |
-      func.getBody() = this and
-      result = func.getThisParameter()
-    )
-  }
 }

powershell/ql/lib/semmle/code/powershell/dataflow/TaintTracking.qll

@@ -0,0 +1,12 @@
+/**
+ * Provides classes for performing local (intra-procedural) and
+ * global (inter-procedural) taint-tracking analyses.
+ */
+module TaintTracking {
+  import semmle.code.powershell.dataflow.internal.TaintTrackingImpl::Public
+  private import semmle.code.powershell.dataflow.internal.DataFlowImplSpecific
+  private import semmle.code.powershell.dataflow.internal.TaintTrackingImplSpecific
+  private import codeql.dataflow.TaintTracking
+  private import powershell
+  import TaintFlowMake<Location, PowershellDataFlow, PowershellTaintTracking>
+}

powershell/ql/lib/semmle/code/powershell/dataflow/internal/TaintTrackingImpl.qll

@@ -0,0 +1,7 @@
+import semmle.code.powershell.dataflow.internal.TaintTrackingPublic as Public
+
+module Private {
+  import semmle.code.powershell.dataflow.DataFlow::DataFlow as DataFlow
+  import semmle.code.powershell.dataflow.internal.DataFlowImpl as DataFlowInternal
+  import semmle.code.powershell.dataflow.internal.TaintTrackingPrivate
+}

powershell/ql/test/TestUtilities/InlineFlowTestUtil.qll

@@ -7,6 +7,8 @@ import semmle.code.powershell.dataflow.DataFlow
 
 predicate defaultSource(DataFlow::Node src) {
   src.asStmt().getStmt().(Cmd).getCommandName() = ["Source", "Taint"]
+  or
+  src.asParameter().getName().matches(["Source%", "Taint%"])
 }
 
 predicate defaultSink(DataFlow::Node sink) {
@@ -15,5 +17,9 @@ predicate defaultSink(DataFlow::Node sink) {
 
 string getSourceArgString(DataFlow::Node src) {
   defaultSource(src) and
-  src.asStmt().getStmt().(Cmd).getAnArgument().(StringConstExpr).getValue().getValue() = result
+  (
+    src.asStmt().getStmt().(Cmd).getAnArgument().(StringConstExpr).getValue().getValue() = result
+    or
+    src.asParameter().getName().regexpCapture(["Source(.+)", "Taint(.+)"], 1) = result
+  )
 }

powershell/ql/test/library-tests/dataflow/params/global.ps1

@@ -0,0 +1,3 @@
+param([string]$Source)
+
+Sink $Source # $ hasValueFlow

powershell/ql/test/library-tests/dataflow/params/test.expected

@@ -1,5 +1,6 @@
 models
 edges
+| global.ps1:1:7:1:22 | Source | global.ps1:3:6:3:13 | Source | provenance |  |
 | test.ps1:1:14:1:16 | a | test.ps1:2:10:2:12 | a | provenance |  |
 | test.ps1:5:6:5:16 | Source | test.ps1:6:5:6:7 | x | provenance |  |
 | test.ps1:6:5:6:7 | x | test.ps1:1:14:1:16 | a | provenance |  |
@@ -139,6 +140,8 @@ edges
 | test.ps1:39:24:39:31 | second | test.ps1:8:24:8:26 | y | provenance |  |
 | test.ps1:39:32:39:38 | first | test.ps1:8:20:8:22 | x | provenance |  |
 nodes
+| global.ps1:1:7:1:22 | Source | semmle.label | Source |
+| global.ps1:3:6:3:13 | Source | semmle.label | Source |
 | test.ps1:1:14:1:16 | a | semmle.label | a |
 | test.ps1:2:10:2:12 | a | semmle.label | a |
 | test.ps1:5:6:5:16 | Source | semmle.label | Source |
@@ -221,6 +224,7 @@ nodes
 subpaths
 testFailures
 #select
+| global.ps1:3:6:3:13 | Source | global.ps1:1:7:1:22 | Source | global.ps1:3:6:3:13 | Source | $@ | global.ps1:1:7:1:22 | Source | Source |
 | test.ps1:2:10:2:12 | a | test.ps1:5:6:5:16 | Source | test.ps1:2:10:2:12 | a | $@ | test.ps1:5:6:5:16 | Source | Source |
 | test.ps1:9:10:9:12 | x | test.ps1:14:10:14:20 | Source | test.ps1:9:10:9:12 | x | $@ | test.ps1:14:10:14:20 | Source | Source |
 | test.ps1:10:10:10:12 | y | test.ps1:15:11:15:21 | Source | test.ps1:10:10:10:12 | y | $@ | test.ps1:15:11:15:21 | Source | Source |