Fix crashes in Clojure-related hooks: NPE on nil var root and CCE in traceGenericCmp - #1065
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The AFTER hook on clojure.lang.Var.getRawRoot dereferenced the result without a null check, throwing a NullPointerException for non-dynamic vars with a nil root (e.g. riddley 0.2.2) and aborting fuzzing during target class loading. Skip the contains check when the result is null and add a regression test.
mapHookInternal and setHookInternal find bracketing keys/elements via compareTo, which can succeed across incompatible Number implementations (e.g. clojure.lang.Ratio vs. java.lang.Double). The unboxing in traceGenericCmp requires both operands to have the same runtime class and otherwise throws a ClassCastException. Only trace comparisons when the bracketing key/element has the same class as the lookup key and add regression tests.
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Summary
Two fixes for crashes in built-in hooks discovered while fuzzing Clojure projects.
In both cases the exception is thrown from inside the fuzz target's class loading (
ExceptionInInitializerError) and aborts fuzzing before any iteration runs.1. NPE in
ClojureLangHooks.clojureMarkContainson nil var rootThe AFTER hook on
clojure.lang.Var.getRawRootdereferenced the hook result without a null check. Reading a non-dynamic var with anilroot (e.g.(def ^:private bb? (System/getProperty "babashka.version"))inriddley 0.2.2, pulled in transitively bymanifold->potemkin->riddley) passesresult = nullinto the hook, throwing an NPE.Skip the contains check when the result is
null.2.
ClassCastExceptioninTraceCmpHooks.mapHookInternal/setHookInternalBracketing keys/elements are found via
compareTo, which can succeed across incompatibleNumberimplementations (e.g.clojure.lang.Ratiovs.java.lang.Doublein a sorted map). The unboxing intraceGenericCmprequires both operands to have the same runtime class and otherwise throws aClassCastException.Only trace comparisons when the bracketing key/element has the same runtime class as the lookup key/element.
Testing
ClojureLangHooksTestandTraceCmpHooksTest.mainand pass with the fix.