Files
codeql/javascript/ql/lib/semmle/javascript/Arrays.qll
2022-02-21 15:02:21 +01:00

410 lines
14 KiB
Plaintext

import javascript
private import semmle.javascript.dataflow.InferredTypes
private import semmle.javascript.dataflow.internal.PreCallGraphStep
/**
* Classes and predicates for modeling TaintTracking steps for arrays.
*/
module ArrayTaintTracking {
/**
* A taint propagating data flow edge caused by the builtin array functions.
*/
private class ArrayFunctionTaintStep extends TaintTracking::SharedTaintStep {
override predicate arrayStep(DataFlow::Node pred, DataFlow::Node succ) {
arrayFunctionTaintStep(pred, succ, _)
}
}
/**
* Holds if there is a taint propagating data flow edge from `pred` to `succ` caused by a call `call` to a builtin array functions.
*/
predicate arrayFunctionTaintStep(DataFlow::Node pred, DataFlow::Node succ, DataFlow::CallNode call) {
// `array.map(function (elt, i, ary) { ... })`: if `array` is tainted, then so are
// `elt` and `ary`; similar for `forEach`
exists(Function f |
call.getArgument(0).getAFunctionValue(0).getFunction() = f and
call.(DataFlow::MethodCallNode).getMethodName() = ["map", "forEach"] and
pred = call.getReceiver() and
succ = DataFlow::parameterNode(f.getParameter([0, 2]))
)
or
// `array.map` with tainted return value in callback
exists(DataFlow::FunctionNode f |
call.(DataFlow::MethodCallNode).getMethodName() = "map" and
call.getArgument(0) = f and // Require the argument to be a closure to avoid spurious call/return flow
pred = f.getAReturn() and
succ = call
)
or
// `array.filter(x => x)` keeps the taint
call.(DataFlow::MethodCallNode).getMethodName() = "filter" and
pred = call.getReceiver() and
succ = call and
exists(DataFlow::FunctionNode callback | callback = call.getArgument(0).getAFunctionValue() |
callback.getParameter(0).getALocalUse() = callback.getAReturn()
)
or
// `array.reduce` with tainted value in callback
call.(DataFlow::MethodCallNode).getMethodName() = "reduce" and
pred = call.getArgument(0).(DataFlow::FunctionNode).getAReturn() and // Require the argument to be a closure to avoid spurious call/return flow
succ = call
or
// `array.push(e)`, `array.unshift(e)`: if `e` is tainted, then so is `array`.
pred = call.getAnArgument() and
succ.(DataFlow::SourceNode).getAMethodCall(["push", "unshift"]) = call
or
// `array.push(...e)`, `array.unshift(...e)`: if `e` is tainted, then so is `array`.
pred = call.getASpreadArgument() and
// Make sure we handle reflective calls
succ = call.getReceiver().getALocalSource() and
call.getCalleeName() = ["push", "unshift"]
or
// `array.splice(i, del, e)`: if `e` is tainted, then so is `array`.
pred = call.getArgument(2) and
succ.(DataFlow::SourceNode).getAMethodCall("splice") = call
or
// `e = array.pop()`, `e = array.shift()`, or similar: if `array` is tainted, then so is `e`.
call.(DataFlow::MethodCallNode).calls(pred, ["pop", "shift", "slice", "splice"]) and
succ = call
or
// `e = Array.from(x)`: if `x` is tainted, then so is `e`.
call = arrayFromCall() and
pred = call.getAnArgument() and
succ = call
or
// `e = arr1.concat(arr2, arr3)`: if any of the `arr` is tainted, then so is `e`.
call.(DataFlow::MethodCallNode).calls(pred, "concat") and
succ = call
or
call.(DataFlow::MethodCallNode).getMethodName() = "concat" and
succ = call and
pred = call.getAnArgument()
or
// find
// `e = arr.find(callback)`
call = arrayFindCall(pred) and
succ = call
}
}
/**
* Classes and predicates for modeling data-flow for arrays.
*/
private module ArrayDataFlow {
private import DataFlow::PseudoProperties
/**
* A step modeling the creation of an Array using the `Array.from(x)` method.
* The step copies the elements of the argument (set, array, or iterator elements) into the resulting array.
*/
private class ArrayFrom extends DataFlow::SharedFlowStep {
override predicate loadStoreStep(
DataFlow::Node pred, DataFlow::Node succ, string fromProp, string toProp
) {
exists(DataFlow::CallNode call |
call = arrayFromCall() and
pred = call.getArgument(0) and
succ = call and
fromProp = arrayLikeElement() and
toProp = arrayElement()
)
}
}
/**
* A step modeling an array copy where the spread operator is used.
* The result is essentially array concatenation.
*
* Such a step can occur both with the `push` and `unshift` methods, or when creating a new array.
*/
private class ArrayCopySpread extends DataFlow::SharedFlowStep {
override predicate loadStoreStep(
DataFlow::Node pred, DataFlow::Node succ, string fromProp, string toProp
) {
fromProp = arrayLikeElement() and
toProp = arrayElement() and
(
exists(DataFlow::MethodCallNode mcn |
mcn.getMethodName() = ["push", "unshift"] and
pred = mcn.getASpreadArgument() and
succ = mcn.getReceiver().getALocalSource()
)
or
pred = succ.(DataFlow::ArrayCreationNode).getASpreadArgument()
)
}
}
/**
* A step for storing an element on an array using `arr.push(e)` or `arr.unshift(e)`.
*/
private class ArrayAppendStep extends DataFlow::SharedFlowStep {
override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
prop = arrayElement() and
exists(DataFlow::MethodCallNode call |
call.getMethodName() = ["push", "unshift"] and
element = call.getAnArgument() and
obj.getAMethodCall() = call
)
}
}
/**
* A node that reads or writes an element from an array inside a for-loop.
*/
private class ArrayIndexingAccess extends DataFlow::Node {
DataFlow::PropRef read;
ArrayIndexingAccess() {
read = this and
TTNumber() =
unique(InferredType type | type = read.getPropertyNameExpr().flow().analyze().getAType()) and
exists(VarAccess i, ExprOrVarDecl init |
i = read.getPropertyNameExpr() and init = any(ForStmt f).getInit()
|
i.getVariable().getADefinition() = init or
i.getVariable().getADefinition().(VariableDeclarator).getDeclStmt() = init
)
}
}
/**
* A step for reading/writing an element from an array inside a for-loop.
* E.g. a read from `foo[i]` to `bar` in `for(var i = 0; i < arr.length; i++) {bar = foo[i]}`.
*/
private class ArrayIndexingStep extends DataFlow::SharedFlowStep {
override predicate loadStep(DataFlow::Node obj, DataFlow::Node element, string prop) {
exists(ArrayIndexingAccess access |
prop = arrayElement() and
obj = access.(DataFlow::PropRead).getBase() and
element = access
)
}
override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
exists(ArrayIndexingAccess access |
prop = arrayElement() and
element = access.(DataFlow::PropWrite).getRhs() and
access = obj.getAPropertyWrite()
)
}
}
/**
* A step for retrieving an element from an array using `.pop()` or `.shift()`.
* E.g. `array.pop()`.
*/
private class ArrayPopStep extends DataFlow::SharedFlowStep {
override predicate loadStep(DataFlow::Node obj, DataFlow::Node element, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = ["pop", "shift"] and
prop = arrayElement() and
obj = call.getReceiver() and
element = call
)
}
}
/**
* A step for iterating an array using `map` or `forEach`.
*
* Array elements can be loaded from the array `arr` to `e` in e.g: `arr.forEach(e => ...)`.
*
* And array elements can be stored into a resulting array using `map(...)`.
* E.g. in `arr.map(e => foo)`, the resulting array (`arr.map(e => foo)`) will contain the element `foo`.
*
* And the second parameter in the callback is the array ifself, so there is a `loadStoreStep` from the array to that second parameter.
*/
private class ArrayIteration extends PreCallGraphStep {
override predicate loadStep(DataFlow::Node obj, DataFlow::Node element, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = ["map", "forEach"] and
prop = arrayElement() and
obj = call.getReceiver() and
element = call.getCallback(0).getParameter(0)
)
}
override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = "map" and
prop = arrayElement() and
element = call.getCallback(0).getAReturn() and
obj = call
)
}
override predicate loadStoreStep(DataFlow::Node pred, DataFlow::SourceNode succ, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = ["map", "forEach"] and
prop = arrayElement() and
pred = call.getReceiver() and
succ = call.getCallback(0).getParameter(2)
)
}
}
/**
* A step for creating an array and storing the elements in the array.
*/
private class ArrayCreationStep extends DataFlow::SharedFlowStep {
override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
exists(DataFlow::ArrayCreationNode array, int i |
element = array.getElement(i) and
obj = array and
if array = any(PromiseAllCreation c).getArrayNode()
then prop = arrayElement(i)
else prop = arrayElement()
)
}
}
/**
* A step modeling that `splice` can insert elements into an array.
* For example in `array.splice(i, del, e)`: if `e` is tainted, then so is `array
*/
private class ArraySpliceStep extends DataFlow::SharedFlowStep {
override predicate storeStep(DataFlow::Node element, DataFlow::SourceNode obj, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = "splice" and
prop = arrayElement() and
element = call.getArgument(2) and
call = obj.getAMethodCall()
)
}
}
/**
* A step for modeling `concat`.
* For example in `e = arr1.concat(arr2, arr3)`: if any of the `arr` is tainted, then so is `e`.
*/
private class ArrayConcatStep extends DataFlow::SharedFlowStep {
override predicate loadStoreStep(DataFlow::Node pred, DataFlow::Node succ, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = "concat" and
prop = arrayElement() and
(pred = call.getReceiver() or pred = call.getAnArgument()) and
succ = call
)
}
}
/**
* A step for modeling that elements from an array `arr` also appear in the result from calling `slice`/`splice`/`filter`.
*/
private class ArraySliceStep extends DataFlow::SharedFlowStep {
override predicate loadStoreStep(DataFlow::Node pred, DataFlow::Node succ, string prop) {
exists(DataFlow::MethodCallNode call |
call.getMethodName() = ["slice", "splice", "filter"] and
prop = arrayElement() and
pred = call.getReceiver() and
succ = call
)
}
}
/**
* A step modeling that elements from an array `arr` are received by calling `find`.
*/
private class ArrayFindStep extends DataFlow::SharedFlowStep {
override predicate loadStep(DataFlow::Node pred, DataFlow::Node succ, string prop) {
exists(DataFlow::CallNode call |
call = arrayFindCall(pred) and
succ = call and
prop = arrayElement()
)
}
}
}
private import ArrayLibraries
/**
* Classes and predicates modeling various libraries that work on arrays or array-like structures.
*/
private module ArrayLibraries {
private import DataFlow::PseudoProperties
/**
* Gets a call to `Array.from` or a polyfill implementing the same functionality.
*/
DataFlow::CallNode arrayFromCall() {
result = DataFlow::globalVarRef("Array").getAMemberCall("from")
or
result = DataFlow::moduleImport("array-from").getACall()
}
/**
* Gets a call to `Array.prototype.find` or a polyfill implementing the same functionality.
*/
DataFlow::CallNode arrayFindCall(DataFlow::Node array) {
result.(DataFlow::MethodCallNode).getMethodName() = "find" and
array = result.getReceiver()
or
result = DataFlow::moduleImport(["array.prototype.find", "array-find"]).getACall() and
array = result.getArgument(0)
}
/**
* A taint step through the `arrify` library, or other libraries that (maybe) convert values into arrays.
*/
private class ArrayifyStep extends TaintTracking::SharedTaintStep {
override predicate step(DataFlow::Node pred, DataFlow::Node succ) {
exists(API::CallNode call | call = API::moduleImport(["arrify", "array-ify"]).getACall() |
pred = call.getArgument(0) and succ = call
)
}
}
/**
* Gets a call to a library that copies the elements of an array into another array.
* E.g. `array-union` that creates a union of multiple arrays, or `array-uniq` that creates an array with unique elements.
*/
DataFlow::CallNode arrayCopyCall(DataFlow::Node array) {
result = API::moduleImport(["array-union", "array-uniq", "uniq"]).getACall() and
array = result.getAnArgument()
}
/**
* A taint step for a library that copies the elements of an array into another array.
*/
private class ArrayCopyTaint extends TaintTracking::SharedTaintStep {
override predicate step(DataFlow::Node pred, DataFlow::Node succ) {
exists(DataFlow::CallNode call |
call = arrayCopyCall(pred) and
succ = call
)
}
}
/**
* A loadStoreStep for a library that copies the elements of an array into another array.
*/
private class ArrayCopyLoadStore extends DataFlow::SharedFlowStep {
override predicate loadStoreStep(DataFlow::Node pred, DataFlow::Node succ, string prop) {
exists(DataFlow::CallNode call |
call = arrayCopyCall(pred) and
succ = call and
prop = arrayElement()
)
}
}
/**
* A taint step through a call to `Array.prototype.flat` or a polyfill implementing array flattening.
*/
private class ArrayFlatStep extends TaintTracking::SharedTaintStep {
override predicate step(DataFlow::Node pred, DataFlow::Node succ) {
exists(DataFlow::CallNode call | succ = call |
call.(DataFlow::MethodCallNode).getMethodName() = "flat" and
pred = call.getReceiver()
or
call =
API::moduleImport(["array-flatten", "arr-flatten", "flatten", "array.prototype.flat"])
.getACall() and
pred = call.getAnArgument()
)
}
}
}