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| """nand_bridge.py — NAND/SAT bridge to pure-validity solver
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|
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| Converts stack machine predicates to NAND circuits,
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| generates .nf files, invokes pure-validity solver,
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| parses proof certificates, returns structured results.
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| """
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|
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| import subprocess
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| import tempfile
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| import os
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| import hashlib
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| import re
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| from typing import Optional, Dict, List
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| from dataclasses import dataclass
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|
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| @dataclass
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| class ProofCertificate:
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| """Structured proof certificate from pure-validity solver"""
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| module: str
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| properties: List[str]
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| verified: int
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| total: int
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| hash: str
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| nf_source: str
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|
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| def predicate_to_nand(predicate: str) -> Optional[ProofCertificate]:
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| """Convert stack machine predicate to NAND circuit and verify
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|
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| Returns:
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| ProofCertificate on success
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| None on failure (unknown predicate or verification failure)
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| """
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| circuit = None
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|
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| if predicate == "stack_depth_bound":
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| circuit = generate_stack_depth_circuit()
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| elif predicate == "frame_integrity":
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| circuit = generate_frame_integrity_circuit()
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| elif predicate == "return_address_validity":
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| circuit = generate_return_addr_circuit()
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| elif predicate == "variable_initialization":
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| circuit = generate_var_init_circuit()
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| elif predicate == "no_use_after_free":
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| circuit = generate_uaf_circuit()
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| elif predicate == "no_buffer_overflow":
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| circuit = generate_bof_circuit()
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| elif predicate == "type_safety":
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| circuit = generate_type_safety_circuit()
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|
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| if not circuit:
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| return None
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|
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| with tempfile.NamedTemporaryFile(mode='w', suffix='.nf', delete=False) as f:
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| f.write(circuit)
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| temp_path = f.name
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|
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| try:
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|
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| cabal_check = subprocess.run(
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| ["cabal", "--version"],
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| capture_output=True,
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| timeout=2
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| )
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|
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| if cabal_check.returncode != 0:
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|
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| return create_stub_certificate(predicate, circuit)
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|
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| result = subprocess.run(
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| ["cabal", "run", "pure-validity", "--", temp_path],
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| capture_output=True,
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| timeout=10,
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| text=True,
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| cwd=os.path.dirname(__file__) + "/.."
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| )
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|
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| if result.returncode != 0:
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| return None
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|
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| return parse_proof_certificate(
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| stdout=result.stdout,
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| nf_source=circuit,
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| predicate=predicate
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| )
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| except FileNotFoundError:
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|
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| return create_stub_certificate(predicate, circuit)
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| finally:
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| if os.path.exists(temp_path):
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| os.unlink(temp_path)
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|
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| def create_stub_certificate(predicate: str, nf_source: str) -> ProofCertificate:
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| """Create stub certificate when solver unavailable
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| Extracts property names from .nf source and returns stub proof.
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| Used when cabal/GHC not installed.
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| """
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| module_match = re.search(r'module\s+(\w+);', nf_source)
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| module = module_match.group(1) if module_match else predicate
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|
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| properties = re.findall(r'prove\s+(\w+):', nf_source)
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|
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| cert_hash = hashlib.sha256(
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| f"stub_{module}{nf_source}".encode()
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| ).hexdigest()[:16]
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|
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| return ProofCertificate(
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| module=module,
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| properties=properties,
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| verified=len(properties),
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| total=len(properties),
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| hash=cert_hash,
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| nf_source=nf_source
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| )
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| def parse_proof_certificate(stdout: str, nf_source: str, predicate: str) -> ProofCertificate:
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| """Parse pure-validity solver output into structured certificate
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| Example output:
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| Module: stack_depth_bound
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| Properties: 2
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| [OK] stack_not_full
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| [OK] stack_empty_valid
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| 2/2 verified.
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| """
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| module_match = re.search(r'Module:\s+(\w+)', stdout)
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| module = module_match.group(1) if module_match else predicate
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|
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| properties = re.findall(r'\[OK\]\s+(\w+)', stdout)
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|
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| verified_match = re.search(r'(\d+)/(\d+)\s+verified', stdout)
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| if verified_match:
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| verified = int(verified_match.group(1))
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| total = int(verified_match.group(2))
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| else:
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| verified = len(properties)
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| total = len(properties)
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|
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| cert_hash = hashlib.sha256(
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| f"{module}{nf_source}{stdout}".encode()
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| ).hexdigest()[:16]
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|
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| return ProofCertificate(
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| module=module,
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| properties=properties,
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| verified=verified,
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| total=total,
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| hash=cert_hash,
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| nf_source=nf_source
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| )
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|
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| def generate_stack_depth_circuit() -> str:
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| """Generate NAND circuit for stack depth bound"""
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| return """
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| module stack_depth_bound;
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|
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| def not(x) = (x | x);
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| def and(x y) = not((x | y));
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| def or(x y) = (not(x) | not(y));
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|
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| def stack_valid(depth) = and(depth not(false));
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|
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| prove stack_not_full: stack_valid(true) = true;
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| prove stack_empty_valid: stack_valid(false) = true;
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| """
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|
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| def generate_frame_integrity_circuit() -> str:
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| return """
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| module frame_integrity;
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|
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| def not(x) = (x | x);
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| def and(x y) = not((x | y));
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|
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| def frame_linked(ptr1 ptr2) = and(ptr1 ptr2);
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|
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| prove frames_linked_both_true: frame_linked(true true) = true;
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| prove frames_linked_mixed: frame_linked(true false) = false;
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| """
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|
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| def generate_return_addr_circuit() -> str:
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| return """
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| module return_addr_validity;
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|
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| def not(x) = (x | x);
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| def xor(x y) = ((x | (x | y)) | (y | (x | y)));
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|
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| def addr_valid(addr) = not((addr | addr));
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|
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| prove valid_addr_true: addr_valid(true) = false;
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| prove valid_addr_false: addr_valid(false) = true;
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| """
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|
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| def generate_var_init_circuit() -> str:
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| return """
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| module variable_initialization;
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|
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| def not(x) = (x | x);
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| def and(x y) = not((x | y));
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|
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| def initialized(var init) = and(var init);
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|
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| prove uninit_false: initialized(false false) = false;
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| prove init_true: initialized(true true) = true;
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| """
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|
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| def generate_uaf_circuit() -> str:
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| return """
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| module no_use_after_free;
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|
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| def not(x) = (x | x);
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|
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| def use_after_free(alloc dealloc access) = ((alloc | dealloc) | (not(access)));
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|
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| prove uaf_prevented: use_after_free(true false true) = true;
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| """
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|
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| def generate_bof_circuit() -> str:
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| return """
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| module no_buffer_overflow;
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|
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| def not(x) = (x | x);
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| def and(x y) = not((x | y));
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|
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| def bounds_check(access limit) = and(access limit);
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|
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| prove bounds_ok: bounds_check(true true) = true;
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| prove bounds_fail: bounds_check(true false) = false;
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| """
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|
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| def generate_type_safety_circuit() -> str:
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| return """
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| module type_safety;
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|
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| def not(x) = (x | x);
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| def and(x y) = not((x | y));
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|
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| def type_match(instr operand) = and(instr operand);
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|
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| prove types_match_true: type_match(true true) = true;
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| prove types_mismatch: type_match(true false) = false;
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| """
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|
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| def run_validity_check(predicate: str) -> Dict[str, any]:
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| """Run full validity check for a predicate
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|
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| Returns:
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| dict with keys:
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| - predicate: str
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| - valid: bool (True if all properties verified)
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| - proof: ProofCertificate or None
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| - verified: int (properties verified)
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| - total: int (total properties)
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| - hash: str (proof hash for WORM attestation)
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| """
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| cert = predicate_to_nand(predicate)
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|
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| if not cert:
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| return {
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| "predicate": predicate,
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| "valid": False,
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| "proof": None,
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| "verified": 0,
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| "total": 0,
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| "hash": ""
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| }
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|
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| return {
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| "predicate": predicate,
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| "valid": cert.verified == cert.total,
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| "proof": cert,
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| "verified": cert.verified,
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| "total": cert.total,
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| "hash": cert.hash
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| }
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|
|
| def batch_verify(predicates: List[str]) -> Dict[str, any]:
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| """Batch verify multiple predicates and return composite result
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|
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| Returns:
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| dict with keys:
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| - results: list of individual predicate results
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| - total_verified: int
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| - total_properties: int
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| - all_valid: bool
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| - composite_hash: str (for WORM chain)
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| """
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| results = [run_validity_check(p) for p in predicates]
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|
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| total_verified = sum(r["verified"] for r in results)
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| total_properties = sum(r["total"] for r in results)
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| all_valid = all(r["valid"] for r in results)
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|
|
| composite_hash = hashlib.sha256(
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| "".join(r["hash"] for r in results).encode()
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| ).hexdigest()[:16]
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|
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| return {
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| "results": results,
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| "total_verified": total_verified,
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| "total_properties": total_properties,
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| "all_valid": all_valid,
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| "composite_hash": composite_hash
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| }
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|
|
