feat(ast): Add initial variable support

Author: GeekMasher

ql/lib/codeql/bicep/ast/Stmts.qll

@@ -141,7 +141,9 @@ class UserDefinedFunction extends AstNode instanceof UserDefinedFunctionImpl {
  */
 class Parameter extends AstNode instanceof ParameterImpl {
   /** Gets the name of the parameter. */
-  Idents getName() { result = ParameterImpl.super.getName() }
+  Idents getIdentifier() { result = ParameterImpl.super.getName() }
+
+  string getName() { result = this.getIdentifier().getName() }
 
   /** Gets the type of the parameter. */
   Type getType() { result = ParameterImpl.super.getType() }

ql/lib/codeql/bicep/ast/Variables.qll

@@ -1,8 +1,10 @@
 /**
  *  Bicep variable declarations.
  */
+
 private import bicep
 private import AstNodes
+private import Calls
 private import Idents
 private import Stmts
 private import codeql.bicep.controlflow.BasicBlocks as BasicBlocks
@@ -14,13 +16,198 @@ private import internal.VariableDeclaration
  *  A VariableDeclaration unknown AST node.
  */
 class VariableDeclaration extends AstNode instanceof VariableDeclarationImpl {
-    /**
-     * Gets the identifier of the variable declaration.
-     */
-    Idents getIdentifier() { result = VariableDeclarationImpl.super.getIdentifier() }
-    
-    /**
-     * Gets the initializer expression of the variable declaration.
-     */
-    Expr getInitializer() { result = VariableDeclarationImpl.super.getInitializer() }
+  /**
+   * Gets the identifier of the variable declaration.
+   */
+  Idents getIdentifier() { result = VariableDeclarationImpl.super.getIdentifier() }
+
+  /**
+   * Gets the initializer expression of the variable declaration.
+   */
+  Expr getInitializer() { result = VariableDeclarationImpl.super.getInitializer() }
+}
+
+private predicate variableDecl(AstNode node, string name) {
+  exists(ParameterDeclaration param |
+    param.getName() = name and
+    node = param
+  )
+  or
+  exists(VariableDeclaration vardelc |
+    vardelc.getIdentifier().getName() = name and
+    node = vardelc
+  )
+  or
+  exists(OutputDeclaration output |
+    output.getIdentifier().getName() = name and
+    node = output
+  )
+}
+
+/**
+ * Variable represents a variable defination.
+ */
+class Variable extends MkVariable {
+  private AstNode node;
+  private string name;
+
+  Variable() { this = MkVariable(node, name) }
+
+  string getName() { result = name }
+
+  string toString() { result = "Variable[" + name + "]" }
+
+  AstNode getAstNode() { result = node }
+
+  /**
+   *  Get the location of this variable.
+   */
+  Location getLocation() { result = node.getLocation() }
+
+  /**
+   * Geta the inner variable of this variable.
+   */
+  VariableAccess getAnAccess() { result.getVariable() = this }
+
+  /**
+   *  Gets the type of this variable, if any.
+   */
+  Type getType() {
+    result = this.getParameter().getType()
+    or
+    result = this.getOutput().getType() 
+  }
+  
+  /**
+   * Gets the parameter of this variable, if any.
+   */
+  ParameterDeclaration getParameter() {
+    exists(ParameterDeclaration param |
+      param.getName() = this.getName() and
+      param.getEnclosingCfgScope() = this.getEnclosingCfgScope() and
+      result = param
+    )
+  }
+
+  /**
+   * Gets the variable declaration of this variable, if any.
+   */
+  OutputDeclaration getOutput() {
+    exists(OutputDeclaration output |
+      output.getIdentifier().getName() = this.getName() and
+      output.getEnclosingCfgScope() = this.getEnclosingCfgScope() and
+      result = output
+    )
+  }
+
+  /**
+   *  Gets the enclosing scope of this variable, if any.
+   */
+  CfgScope getEnclosingCfgScope() { result = node.getEnclosingCfgScope() }
+
+  // Expr getInitializer() { }
+  string getAPrimaryQlClass() { result = "Variable" }
+}
+
+private predicate access(AstNode node, Variable v, string name) {
+  exists(Identifier ident |
+    ident.getName() = name and
+    // Make sure they are not in a declare statement
+    not ident.getParent() instanceof VariableDeclaration and
+    // not ident.getParent() instanceof ParameterDeclaration and
+    // not ident.getParent() instanceof OutputDeclaration and
+    // Make sure they are in the same scope
+    ident.getName() = v.getName() and
+    ident.getEnclosingCfgScope() = v.getEnclosingCfgScope() and
+    ident = node
+  )
+}
+
+/**
+ *  VariableAccess is a class that represents the access to a variable.
+ */
+class VariableAccess extends MkVariableAccess, TVariableAccess {
+  private string name;
+  private AstNode node;
+  private Variable v;
+
+  VariableAccess() { this = MkVariableAccess(node, v, name) }
+
+  string getName() { result = name }
+
+  AstNode getAstNode() { result = node }
+
+  Variable getVariable() { result = v }
+
+  string toString() { result = "VariableAccess[" + name + "]" }
+
+  /**
+   *  Get the location of this variable.
+   */
+  Location getLocation() { result = node.getLocation() }
+
+  /**
+   *  Gets the type of this variable, if any.
+   */
+  Type getType() { result = this.getVariable().getType() }
+
+  /**
+   *  Gets the enclosing scope of this variable, if any.
+   */
+  CfgScope getEnclosingCfgScope() { result = v.getEnclosingCfgScope() }
+
+  string getAPrimaryQlClass() { result = "VariableAccess" }
 }
+
+class VariableWriteAccess extends VariableAccess {
+  VariableWriteAccess() {
+    // Parameter
+    this.getAstNode().getParent() instanceof ParameterDeclaration
+    or
+    // SET
+    this.getAstNode().getParent() instanceof VariableDeclaration
+    or
+    // Output
+    this.getAstNode().getParent() instanceof OutputDeclaration
+  }
+
+  override string getAPrimaryQlClass() { result = "VariableWrite" }
+}
+
+class VariableReadAccess extends VariableAccess {
+  VariableReadAccess() { not this instanceof VariableWriteAccess }
+
+  override string getAPrimaryQlClass() { result = "VariableRead" }
+}
+
+/**
+ * Holds if the variable is written too.
+ */
+// private predicate variableWrite(Variable node) {
+//   exists(Parameter param |
+//     param.getName() = node.getName() and
+//     param.getEnclosingCfgScope() = node.getEnclosingCfgScope()
+//   )
+// }
+cached
+private module Cached {
+  cached
+  newtype TVariable =
+    TResource(Resource resource, string name) { resource.getName() = name } or
+    TVariableDecl(VariableDeclaration varDecl, string name) {
+      varDecl.getIdentifier().getName() = name
+    } or
+    TParameter(ParameterDeclaration param, string name) { param.getName() = name } or
+    TOutput(OutputDeclaration output, string name) { output.getIdentifier().getName() = name } or
+    MkVariable(AstNode definingNode, string name) { variableDecl(definingNode, name) }
+
+  cached
+  newtype TVariableAccess =
+    TIdent(Identifier ident, string name) { ident.getName() = name } or
+    MkVariableAccess(AstNode node, Variable v, string name) { variableAccess(node, v, name) }
+
+  cached
+  predicate variableAccess(AstNode node, Variable v, string name) { access(node, v, name) }
+}
+
+private import Cached