View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0011367 | Taler | wallet (all platforms) | public | 2026-04-30 11:06 | 2026-04-30 15:26 |
| Reporter | Christian Grothoff | Assigned To | Florian Dold | ||
| Priority | urgent | Severity | major | Reproducibility | always |
| Status | assigned | Resolution | open | ||
| Platform | i7 | OS | Debian GNU/Linux | OS Version | squeeze |
| Product Version | git (master) | ||||
| Target Version | 1.6 | ||||
| Summary | 0011367: double-spending fun with pending transactions | ||||
| Description | Torsten on iphone managed the following: - Balance: 5 CHF - p2p send: 4.5 CHF -- transaction: pending (receiver did not yet accept) - p2p send AGAIN: 4.5 CHF *allowed* -- failed to generate QR code (but did NOT say insufficient balance) Main screen then shows 9 CHF outgoing pending transactions with 5 CHF balance. Abort 1st transaction -- hangs in cancellation. Abort 2st transaction -- also hangs in cancellation. AFAIK full balance is not inaccessible to the user. | ||||
| Tags | No tags attached. | ||||
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Please check which wallets are affected, if a wallet-core API change is needed, and plan a way to get locked-up balances unstuck for users where this happened (=> DB fixup?). |
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Strange. First tx should reserve coins internally in the DB, then send them to the Exchange (if necessary spawn a task to withdraw change), receive the purse data back, and THEN generate the talerURI for the receiver. Thus if the user was able to see a QR code and send the talerURI to the receiver, the coins have already arrived at the Exchange. It should never be possible for a second tx to use these reserved coins. Wallet-core should show that (at most) 50Rp are available - or even less if the change didn't arrive yet. Affected wallets: Of course all, since all wallets only display what wallet-core tells them. |
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Could not reproduce "double spending" on Android, second p2p send reports correct available balance (minus pending outgoing). However, p2p send transactions cannot be aborted, they get stuck on "aborting" state. |
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I can't confirm Ivan's finding. On iOS, I could successfully abort a P2P send tx, and the amount was then available for spending. �"id":52 abortTransaction{"transactionId":"txn:peer-push-debit:JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0"} Timestamp: 2026-04-30 15:02:29.483587+02:00 handleStateTransition: Aborting: txn:peer-push-debit:JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0 Timestamp: 2026-04-30 15:02:29.499770+02:00 [9] 15:02:29.501 � WalletCore.swift:157 WalletCore#1 handleResponse(_:_:) {"type":"response","operation":"abortTransaction","id":52,"result":{}} [9] 15:02:29.513 � WalletCore.swift:319 WalletCore#1 handleNotification(_:_:) {"type":"notification","payload":{"type":"transaction-state-transition","transactionId":"txn:peer-push-debit:JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0","oldTxState":{"major":"aborting","minor":"delete-purse"},"newTxState":{"major":"aborting","minor":"delete-purse"},"newStId":16973824}} after that wallet-core made the https call to the exchange: ❓52 DELETE https://exchange.demo.taler.net/purses/JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0 Timestamp: 2026-04-30 15:02:29.514536+02:00 the network answer came after 308ms: ❗️ 52 https://exchange.demo.taler.net/purses/JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0 Timestamp: 2026-04-30 15:02:29.822869+02:00 then the state changed to aborted: [9] 15:02:29.917 � WalletCore.swift:319 WalletCore#1 handleNotification(_:_:) {"type":"notification","payload":{"type":"transaction-state-transition","oldTxState":{"major":"aborting","minor":"delete-purse"},"newTxState":{"major":"aborted"},"transactionId":"txn:peer-push-debit:JR0AFSB8X3Q0WV9D795Z576KEXFZPZJ8EBQ5KX5E43HD39HR9DS0","newStId":84082688}} Took all in all 434 ms. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2026-04-30 11:06 | Christian Grothoff | New Issue | |
| 2026-04-30 11:06 | Christian Grothoff | Status | new => assigned |
| 2026-04-30 11:06 | Christian Grothoff | Assigned To | => Florian Dold |
| 2026-04-30 11:07 | Christian Grothoff | Note Added: 0028495 | |
| 2026-04-30 11:59 | MarcS | Note Added: 0028497 | |
| 2026-04-30 13:34 | avalos | Note Added: 0028499 | |
| 2026-04-30 15:26 | MarcS | Note Added: 0028500 |
