Files
Open_Ultra_SAST/src/openultrasast/cpg/queries/dominance.sc
T

76 lines
4.1 KiB
Python
Raw Normal View History

// Guard dominance for the absence families (model-grounded-detection Req 6.2).
//
// An access-control bug is the ABSENCE of a guard: there is no flow to follow and no crash to reproduce.
// What the model can establish is a consistency violation -- an obligated operation that no discharging guard
// governs, in a file where its siblings are governed by one.
//
// "Governed" is not one relation, because a guard discharges an obligation in three different shapes, and
// asking pure CFG dominance of the operation gets two of them wrong:
//
// 1. identity constraint the guard is INSIDE the operation's own arguments
// Note.query.filter_by(owner_id = current_user.id)
// 2. identity branch the method branches on identity, and the denial is controlled by that condition
// note = ...filter_by(id=nid); if note.owner_id != current_user.id: abort(403)
// (measured: abort(403).controlledBy == [note.owner_id != current_user.id])
// 3. dominating guard a call naming a discharger that dominates the operation -- a check before it
//
// Shape 2 is why `controlledBy` is used rather than `dominatedBy`: the ownership check runs AFTER the fetch,
// so it never dominates the operation, but it does control whether the value escapes.
//
// Parameters: cpgFile, operations, dischargers, function (optional; reported, never used to filter, because
// the sibling comparison needs every operation in the CPG).
//
// Output: a fenced JSON array of {operation, opLine, opMethod, dominatingGuards}.
@main def exec(cpgFile: String, operations: String, dischargers: String, function: String = "") = {
importCpg(cpgFile)
def split(raw: String): List[String] = raw.split(",").map(_.trim).filter(_.nonEmpty).toList
val opNames = split(operations)
val guardTokens = split(dischargers)
// Word-boundary matching, never substring. A discharger token like `user` matched as a substring hits
// `users` inside "SELECT * FROM users WHERE id = ?", marking a textbook IDOR as guarded -- a silent false
// negative on the one family this arbiter exists for.
def mentionsGuard(code: String): Boolean =
guardTokens.exists(g => java.util.regex.Pattern.compile("(?<![A-Za-z0-9_])" + java.util.regex.Pattern.quote(g) + "(?![A-Za-z0-9_])").matcher(code).find())
// Match by CALL NAME, never by code containment: the frontend desugars `Note.query.filter_by(x).first()`
// into a chain of temporaries, and matching on code yields four or five rows for one operation -- some of
// them the bare `tmp1.filter_by` receiver, which carries none of the guards the real call does. A `leaky`
// verdict computed over those extra rows would flag a guarded operation. A dotted spec (`query.get`)
// matches on its trailing segment, which is how the call is named in the graph.
def matchesOperation(name: String): Boolean =
opNames.exists(n => name == n || name == n.split("\\.").last)
val opCalls = cpg.call.filter(c => matchesOperation(c.name)).l
val rows = opCalls.map { op =>
val method = op.method
// 1. identity constraint: a discharger inside the operation's own arguments.
val inArguments = op.argument.code.l.filter(mentionsGuard)
// 2. identity branch: a control structure in this method whose condition names a discharger. The denial
// it guards need not dominate the operation -- it controls whether the fetched value escapes.
val inCondition = method.controlStructure.condition.code.l.filter(mentionsGuard)
// 3. dominating guard: a call naming a discharger that actually dominates the operation.
val dominating = op.dominatedBy.isCall.code.l.filter(mentionsGuard)
val guards = (inArguments ++ inCondition ++ dominating).distinct.map(_.take(120))
ujson.Obj(
"operation" -> op.code.take(200),
"opLine" -> op.lineNumber.getOrElse(-1).toString,
"opMethod" -> method.name,
"dominatingGuards" -> ujson.Arr(guards.map(ujson.Str(_)): _*)
)
}
println("---OUSAST-CPG-BEGIN---")
println(ujson.write(ujson.Arr(rows: _*)))
println("---OUSAST-CPG-END---")
}