| Package | Affected versions | Patched versions |
|---|---|---|
| github.com/open-policy-agent/opa | ≥ 0.33.1, < 0.37.2 | 0.37.2 |
| open policy agent | ≥ 0.33.1, < 0.37.0 | 0.37.0 |
Under certain conditions, pretty-printing an AST that contains synthetic nodes could change the logic of some statements by reordering array literals. Example of policies impacted are those that parse and compare web paths, see the example below.
All of these three conditions have to be met to create an adverse effect:
github.com/open-policy-agent/opa/format package.If any of these three conditions are not met, you are not affected.
Notably, all three would be true if using optimized bundles, i.e. bundles created with opa build -O=1 or higher.
In that case, the optimizer would fulfil condition (1.), the result of that would be pretty-printed when writing the bundle to disk, fulfilling (2.). When the bundle was then used, we'd satisfy (3.).
For example, the process outlined above could turn this rule
hello {
["foo", _] = split(input.resource, "/")
}
into
hello {
[_, "foo"] = split(input.resource, "/")
}
with an input of
{
"resource": "foo/bar"
}
the result would change from
{
"hello": true
}
to (no default value of hello)
{}
The severity was determined to be moderate because the conditions are quite particular. Please note that its only the OPA bundle build process thats affected. An OPA sidecar of version 0.36.0 with an optimized bundle built by OPA 0.32.1 would not face this bug.
Fixed in version 0.37.2.
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