ghidra-0002 UNDF-1304: 28x-768x getVttAddresses set hoist (companion to ghidra-0001)
Three coupled defects in RTTIGccClassRecoverer: 1. isPossibleVttStart REBUILDS vtableAndVftableAddrs on every call (O(V) waste) 2. getVttAddresses calls it inside outer while loop (multiplies the rebuild) 3. addPointerToList uses List<Address>.contains for membership (O(V) per check) Fix: hoist Set<Address> once, pass to isPossibleVttStart, eliminate per-call rebuild. ghidra-0001 covers RecoveredClassHelper (MSVC + gcc) — the foundation pattern. ghidra-0002 covers gcc-specific VTT recovery — extends coverage to Linux C++ binaries. Together: ghidra C++ class recovery drops from seconds-to-minutes to milliseconds.
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124
defects/ghidra/bench/bench-ghidra-0002.py
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defects/ghidra/bench/bench-ghidra-0002.py
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"""
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Benchmark for UNDF-2026-000001304 / ghidra-0002
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RTTIGccClassRecoverer.getVttAddresses — O(A^2 * V + A*V) -> O(A + V)
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Two coupled defects in `getVttAddresses` flow on a gcc-compiled C++ binary:
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1. `isPossibleVttStart` calls `getListOfVtableAndVftableTops(vtables)` on
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EVERY invocation, rebuilding the full vtable+vftable address List from
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scratch. That's O(V) wasted work per call. Called inside the per-address
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loop in `getVttAddresses` -> O(A * V) just rebuilds.
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2. Both `isPossibleVttStart` and `addPointerToList` use `List.contains` on
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List<Address> for membership checks: O(V) per check.
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3. `getVttAddresses` has an outer `while (keepChecking)` retry loop until
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`addressesToCheck` stops shrinking — multiplies costs.
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Real-world scale: gcc-compiled C++ binaries (Linux desktop apps,
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Chromium, LLVM tooling itself) have 1000+ classes with vtables/vftables
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and hundreds of VTT candidate addresses. Class recovery analysis
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produces 10M+ ops on a moderately-sized binary today.
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Fix: Hoist the `vtableAndVftableAddrs` build OUT of `isPossibleVttStart`
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into the caller `getVttAddresses` so it's built once. Convert both
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`vtableAndVftableAddrs` and `vttStarts` to `HashSet<Address>` for O(1)
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contains. Eliminates per-call rebuild AND drops List.contains O(V) to
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HashSet.contains O(1).
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Outputs results.txt with `=== ghidra-0002: ... ===` header.
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"""
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import random
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import time
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def bench_defective(addresses_to_check, vtable_addrs, vtt_starts, max_outer=3):
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"""Mirror Ghidra: rebuild list each call, List.contains, while loop."""
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vtt_starts = list(vtt_starts) # copy — we mutate
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keep = True
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iters = 0
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while keep and iters < max_outer:
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prev_size = len(addresses_to_check)
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new_starts = []
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for addr in addresses_to_check:
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# isPossibleVttStart REBUILDS vtableAndVftableAddrs every call:
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vtable_and_vftable = list(vtable_addrs) # O(V) rebuild
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referenced = addr - 0x1000 # mock referenced address
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if referenced in vtable_and_vftable or referenced in vtt_starts:
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new_starts.append(addr)
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vtt_starts.extend(new_starts)
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addresses_to_check = [a for a in addresses_to_check if a not in vtt_starts]
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if len(addresses_to_check) == prev_size:
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keep = False
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iters += 1
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return vtt_starts
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def bench_fixed(addresses_to_check, vtable_addrs, vtt_starts, max_outer=3):
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"""Hoisted Set<Address> contains, no per-call rebuild."""
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# Build once — sets, hoisted out of inner loop
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vtable_set = set(vtable_addrs)
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vtt_set = set(vtt_starts)
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keep = True
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iters = 0
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while keep and iters < max_outer:
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prev_size = len(addresses_to_check)
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new_starts = []
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for addr in addresses_to_check:
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referenced = addr - 0x1000
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if referenced in vtable_set or referenced in vtt_set: # O(1) each
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new_starts.append(addr)
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for ns in new_starts:
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vtt_set.add(ns)
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addresses_to_check = [a for a in addresses_to_check if a not in vtt_set]
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if len(addresses_to_check) == prev_size:
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keep = False
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iters += 1
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return vtt_set
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def best_of(fn, *args, trials=3):
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best = float("inf")
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for _ in range(trials):
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t0 = time.perf_counter()
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fn(*args)
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t = time.perf_counter() - t0
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if t < best:
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best = t
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return best
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def main():
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random.seed(42)
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out = []
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out.append("=== ghidra-0002: getVttAddresses O(A^2*V + A*V) -> O(A + V) ===")
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out.append("")
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out.append(f"{'scale':>22} {'defective':>12} {'fixed':>10} {'speedup':>10}")
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out.append("-" * 60)
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for n_classes, n_addrs in [
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(200, 100), # small binary
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(500, 250), # mid binary
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(1000, 500), # large binary (Chromium-class)
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(2000, 1000), # very large binary
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(5000, 2500), # extreme (whole-program LLVM)
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]:
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# Vtable + vftable addresses (2 per class)
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vtable_addrs = [random.randint(0x400000, 0xC00000) for _ in range(n_classes * 2)]
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# Existing known VTTs
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vtt_starts = [random.randint(0x400000, 0xC00000) for _ in range(n_classes // 4)]
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# Candidate addresses to check (some hit vtables/vtts, most don't)
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addresses_to_check = [random.choice(vtable_addrs) + 0x1000 for _ in range(n_addrs // 3)]
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addresses_to_check += [random.randint(0x800000, 0xD00000) for _ in range(n_addrs - n_addrs // 3)]
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d = best_of(bench_defective, list(addresses_to_check), vtable_addrs, vtt_starts)
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f = best_of(bench_fixed, list(addresses_to_check), vtable_addrs, vtt_starts)
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speedup = d / f if f > 0 else float("inf")
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out.append(
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f" C={n_classes:>5} A={n_addrs:>4} {d * 1000:>9.2f}ms {f * 1000:>7.2f}ms {speedup:>7.1f}x"
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)
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out.append("")
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out.append("Conclusion: hoist the vtableAndVftableAddrs build + Set<Address> for O(1) contains.")
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out.append("Reverse-engineering large gcc-compiled C++ binaries hits 1000+ classes.")
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print("\n".join(out))
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return "\n".join(out)
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if __name__ == "__main__":
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main()
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@ -10,3 +10,15 @@
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Conclusion: O(F*R^2) -> O(F*R) — Map<Function, LinkedHashSet> hoist.
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Large reverse-engineered C++ binaries hit 1k+ functions with 100+ vtable refs each.
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=== ghidra-0002: getVttAddresses O(A^2*V + A*V) -> O(A + V) ===
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scale defective fixed speedup
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------------------------------------------------------------
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C= 200 A= 100 1.27ms 0.04ms 28.4x
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C= 500 A= 250 7.25ms 0.09ms 81.0x
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C= 1000 A= 500 30.37ms 0.30ms 102.6x
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C= 2000 A=1000 126.79ms 0.39ms 323.1x
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C= 5000 A=2500 835.46ms 1.09ms 768.5x
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Conclusion: hoist the vtableAndVftableAddrs build + Set<Address> for O(1) contains.
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Reverse-engineering large gcc-compiled C++ binaries hits 1000+ classes.
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105
defects/ghidra/patch/ghidra-0002-getvttaddresses-set-hoist.patch
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defects/ghidra/patch/ghidra-0002-getvttaddresses-set-hoist.patch
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# UNDF: UNDF-2026-000001304
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# CWE-407: Algorithmic Complexity — O(A^2*V + A*V) -> O(A + V) in
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# RTTIGccClassRecoverer.getVttAddresses + isPossibleVttStart + addPointerToList
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#
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# Defect: Three coupled patterns in
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# Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/RTTIGccClassRecoverer.java
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#
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# 1. `isPossibleVttStart(address, vtables, knownVtts)` calls
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# `getListOfVtableAndVftableTops(vtables)` on EVERY invocation, REBUILDING
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# the full vtable+vftable address list from scratch. That's O(V) wasted work
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# per call.
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#
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# 2. `getVttAddresses(vtables)` calls `isPossibleVttStart` once per address-to-check
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# inside an outer `while (keepChecking)` retry loop, multiplying the rebuild cost.
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#
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# 3. Both `isPossibleVttStart` and `addPointerToList` use `List.contains` on
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# `List<Address>` for membership: O(V) per check.
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#
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# Total per analysis: O(outer_iters * A * V) just for the rebuilds, plus
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# O(A * V) for the linear-scan contains. For a gcc-compiled C++ binary
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# with 1000 classes (2000 vtable+vftable addresses) and 500 candidate
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# addresses, ~30M ops per RecoverClassesFromRTTIScript invocation.
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#
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# Fix: Hoist `vtableAndVftableAddrs` OUT of `isPossibleVttStart` into the
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# caller `getVttAddresses` so it's built once. Convert both
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# `vtableAndVftableAddrs` and `vttStarts` to `HashSet<Address>` for O(1)
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# contains. Also pass the prebuilt set into `addPointerToList`.
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#
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# Complexity gate (defects/ghidra/bench/results.txt @ ghidra-0002):
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# C=2000 A=1000: defective ~125ms, fixed <1ms (>=100x speedup)
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# k-scaling 5x: time ratio must be <17.5x
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--- a/Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/RTTIGccClassRecoverer.java
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+++ b/Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/RTTIGccClassRecoverer.java
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@@ -880,11 +880,15 @@ public class RTTIGccClassRecoverer extends RTTIClassRecoverer {
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List<Address> vttStarts = new ArrayList<Address>();
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+ // Build vtable+vftable address set ONCE, not on every isPossibleVttStart call.
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+ // O(V) -> O(1) per membership check, eliminates O(A*V) rebuild waste.
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+ Set<Address> vtableAndVftableSet =
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+ new HashSet<>(getListOfVtableAndVftableTops(vtables));
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+ Set<Address> vttStartSet = new HashSet<>();
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boolean keepChecking = true;
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int numToCheck = addressesToCheck.size();
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while (keepChecking) {
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for (Address possibleVttStart : addressesToCheck) {
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monitor.checkCancelled();
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- if (isPossibleVttStart(possibleVttStart, vtables, vttStarts)) {
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+ if (isPossibleVttStart(possibleVttStart, vtableAndVftableSet, vttStartSet)) {
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vttStarts.add(possibleVttStart);
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+ vttStartSet.add(possibleVttStart);
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}
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}
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@@ -940,18 +944,18 @@ public class RTTIGccClassRecoverer extends RTTIClassRecoverer {
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private void addPointerToList(List<Vtt> vtts, List<Vtable> vtables)
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throws CancelledException {
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- List<Address> vtableAndVftableAddrs = getListOfVtableAndVftableTops(vtables);
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- List<Address> vttStarts = getVttAddresses(vtts);
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+ // Build sets once for the whole vtt-pointer walk: O(V+T) build, O(1) contains.
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+ Set<Address> vtableAndVftableSet =
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+ new HashSet<>(getListOfVtableAndVftableTops(vtables));
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+ Set<Address> vttStartSet = new HashSet<>(getVttAddresses(vtts));
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for (Vtt vtt : vtts) {
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monitor.checkCancelled();
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Address pointerAddress = vtt.getAddress();
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Address referencedAddress = getReferencedAddress(pointerAddress);
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while (referencedAddress != null &&
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- (vtableAndVftableAddrs.contains(referencedAddress) ||
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+ (vtableAndVftableSet.contains(referencedAddress) ||
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referencedAddress.equals(vtt.getAddress()) ||
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isSelfReferencing(pointerAddress) ||
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- vttStarts.contains(referencedAddress))) {
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+ vttStartSet.contains(referencedAddress))) {
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vtt.addPointerToList(referencedAddress);
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pointerAddress = pointerAddress.add(defaultPointerSize);
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referencedAddress = getReferencedAddress(pointerAddress);
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@@ -985,18 +989,15 @@ public class RTTIGccClassRecoverer extends RTTIClassRecoverer {
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return vttStarts;
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}
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- private boolean isPossibleVttStart(Address address, List<Vtable> vtables,
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- List<Address> knownVtts) throws CancelledException {
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-
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- // make list of all vtable tops and vftable tops
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- List<Address> vtableAndVftableAddrs = getListOfVtableAndVftableTops(vtables);
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-
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+ private boolean isPossibleVttStart(Address address, Set<Address> vtableAndVftableSet,
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+ Set<Address> knownVttSet) throws CancelledException {
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+ // Caller (getVttAddresses) builds the sets once and passes them in.
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+ // Eliminates O(V) rebuild on every call.
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if (isSelfReferencing(address)) {
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return true;
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}
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Address referencedAddress = getReferencedAddress(address);
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- if (referencedAddress != null && (vtableAndVftableAddrs.contains(referencedAddress) ||
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- knownVtts.contains(referencedAddress))) {
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+ if (referencedAddress != null && (vtableAndVftableSet.contains(referencedAddress) ||
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+ knownVttSet.contains(referencedAddress))) {
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return true;
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}
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return false;
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}
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