- add `getCallable`, `getArg` and `getNode`
- these are `none` for summary calls
- revert "external" uses (they had been changed to `DataFlowSourceCall`)
- still identifying summarized callables by name.
I think ther shoudl perhaps be a `getAUse` next to `getACall`.
- also fix tests, adding a standard taint configuration
Two classes have been inserted into the hierarchies:
- `NonLibraryDataFlowCallable` with a method `getACall2`.
This method implements "get a call, not considering flow summaries".
For `NonLibraryDataFlowCallable`s, `getACall` will defer to `getACall2`.
While you could have a synthesised call to such a callable,
it would not correspond to a `CallNode`.
- `NonLibraryDataFlowSourceCall` with methods
`getArg2` and `getCallable2`. These also refer to a call graph that
does not consider flow summaries.
`getArg2` is used to synthesise pre-update nodes for arguments.
`getCallable2` is used in `connects` to compute argument passing.
This is used to define data flow nodes for overflow arguments.
`getACall2` ensures that `LibraryCallableValue::getACall` is not called
when the charpred of `FunctionCall` is evaluated.
- Branch predicates are made simple. In particular, they do not try to detect library calls.
- All branches based on `CallNode`s are gathered into one.
- That branch has been given a class `NonSpecialCall`, which is the new parent of call classes based on `CallNode`s. (Those classes now have more involved charpreds.)
- A new such class, 'LambdaCall` has been split out from `FunctionCall` to allow the latter to replace its
general `CallNode` field with a specific `FunctionValue` one.
- `NonSpecialCall` is not an abstract class, but it has some abstract overrides. Therefor, it is not
considered a resolved call in the test `UnresolvedCalls.qll`.
I think we should write our tests in a way that puts points-to in the
best condition to resolve calls. Although this specific change did not
change much, it should help set us up for success in the future 👍
Since that apparently impacts call graph resolution with points-to :O
Also interesting that global flow was only not working for those cases
because of the tricky ifs... still need to 100% figure out how those ifs
are messing up the analysis :|
By giving all variables unique names
I also added a comment with the function name from the normal tests, so
its' easily visible what these tests are testing
In `x.arg = TAINTED_STRING` there is a store step to the attribute `arg`
of `x`. In our taint modeling, we allow _any_ store step with the code
below. This means that we also say there is a taint-step directly from
`TAINTED_STRING` to `x` :|
```codeql
// construction by literal
// TODO: Not limiting the content argument here feels like a BIG hack, but we currently get nothing for free :|
DataFlowPrivate::storeStep(nodeFrom, _, nodeTo)
```
