This looks for nodes annotated with `t[never]` in the test that are
reachable in the CFG. This should not happen (it messes with various
queries, e.g. the "mixed returns" query), but the test shows that in a
few particular cases (involving the `match` statement where all cases
contain `return`s), we _do_ have reachable nodes that shouldn't be.
This one demonstrates a bug in the current CFG. In a dictionary
comprehension `{k: v for k, v in d.items()}`, we evaluate the value
before the key, which is incorrect. (A fix for this bug has been
implemented in a separate PR.)
These use the annotated, self-verifying test files to check various
consistency requirements.
Some of these may be expressing the same thing in different ways, but
it's fairly cheap to keep them around, so I have not attempted to
produce a minimal set of queries for this.
These tests consist of various Python constructions (hopefully a
somewhat comprehensive set) with specific timestamp annotations
scattered throughout. When the tests are run using the Python 3
interpreter, these annotations are checked and compared to the "current
timestamp" to see that they are in agreement. This is what makes the
tests "self-validating".
There are a few different kinds of annotations: the basic `t[4]` style
(meaning this is executed at timestamp 4), the `t[dead(4)]` variant
(meaning this _would_ happen at timestamp 4, but it is in a dead
branch), and `t[never]` (meaning this is never executed at all).
In addition to this, there is a query, MissingAnnotations, which checks
whether we have applied these annotations maximally. Many expression
nodes are not actually annotatable, so there is a sizeable list of
excluded nodes for that query.
We won't be able to run these tests until Python 3.15 is actually out
(and our CI is using it), so it seemed easiest to just put them in their
own test directory.
Looking at the results of the the previous DCA run, there was a bunch of
false positives where `bind` was being used with a `AF_UNIX` socket (a
filesystem path encoded as a string), not a `(host, port)` tuple. These
results should be excluded from the query, as they are not vulnerable.
Ideally, we would just add `.TupleElement[0]` to the MaD sink, except we
don't actually support this in Python MaD...
So, instead I opted for a more low-tech solution: check that the
argument in question flows from a tuple in the local scope.
This eliminates a bunch of false positives on `python/cpython` leaving
behind four true positive results.
This takes care of most of the false negatives from the preceding
commit.
Additionally, we add models for some known wrappers of `socket.socket`
from the `gevent` and `eventlet` packages.
Adds test cases from github/codeql#21582 demonstrating false negatives:
- Address stored in class attribute (`self.bind_addr`)
- `os.environ.get` with insecure default value
- `gevent.socket` (alternative socket module)
The fix may look a bit obscure, so here's what's going on.
When we see `from . import helper`, we create an `ImportExpr` with level
equal to 1 (corresponding to the number of dots). To resolve such
imports, we compute the name of the enclosing package, as part of
`ImportExpr.qualifiedTopName()`. For this form of import expression, it
is equivalent to `this.getEnclosingModule().getPackageName()`. But
`qualifiedTopName` requires that `valid_module_name` holds for its
result, and this was _not_ the case for namespace packages.
To fix this, we extend `valid_module_name` to include the module names
of _any_ folder, not just regular package (which are the ones where
there's a `__init__.py` in the folder). Note that this doesn't simply
include all folders -- only the ones that result in valid module names
in Python.
Adds `hasOverloadDecorator` as a predicate on functions. It looks for
decorators called `overload` or `something.overload` (usually
`typing.overload` or `t.overload`). These are then filtered out in the
predicates that (approximate) resolving methods according to the MRO.
As the test introduced in the previous commit shows, this removes the
spurious resolutions we had before.
The ones that no longer require points-to no longer import
`LegacyPointsTo`. The ones that do use the specific
`...MetricsWithPointsTo` classes that are applicable.
