fa6b053b5c mempool: persist with XOR (MarcoFalke)
Pull request description:
Currently the `mempool.dat` file stores data received from remote peers as-is. This may be problematic when a program other than Bitcoin Core tries to interpret them by accident. For example, an anti-virus program or other program may scan the file and move it into quarantine, or delete it, or corrupt it.
While the local wallet is expected to re-submit any pending transactions, unrelated transactions may be missing from the mempool after a restart. This may cause fee estimates to be off, or may cause block relay to be slower.
Fix this, similar to https://github.com/bitcoin/bitcoin/pull/6650, by rolling a random XOR pattern over the dat file when writing or reading it.
Obviously this can only protect against programs that accidentally and unintentionally are trying to mess with the dat file. Any program that intentionally wants to mess with the dat file can still trivially do so.
ACKs for top commit:
achow101:
re-ACK fa6b053b5c
glozow:
reACK fa6b053b5c
ismaelsadeeq:
ACK fa6b053b5c
Tree-SHA512: ded2ce3d81bc944b828263534e3178a1e45a914fe8e024f4a14c6561a73e301820944ecc75dd704b3d4221a7a3a5c0597ccab79546250c1197609ee981fe324e
32c1dd1ad6 [test] mempool coins disappearing mid-package evaluation (glozow)
a67f460c3f [refactor] split setup in mempool_limit test (glozow)
d08696120e [test framework] add ability to spend only confirmed utxos (glozow)
3ea71feb11 [validation] don't LimitMempoolSize in any subpackage submissions (glozow)
d227b7234c [validation] return correct result when already-in-mempool tx gets evicted (glozow)
9698b81828 [refactor] back-fill results in AcceptPackage (glozow)
8ad7ad3392 [validation] make PackageMempoolAcceptResult members mutable (glozow)
03b87c11ca [validation] add AcceptSubPackage to delegate Accept* calls and clean up m_view (glozow)
3f01a3dab1 [CCoinsViewMemPool] track non-base coins and allow Reset (glozow)
7d7f7a1189 [policy] check for duplicate txids in package (glozow)
Pull request description:
While we are evaluating a package, we split it into "subpackages" for evaluation (currently subpackages all have size 1 except the last one). If a subpackage has size 1, we may add a tx to mempool and call `LimitMempoolSize()`, which evicts transactions if the mempool gets full. We handle the case where the just-submitted transaction is evicted immediately, but we don't handle the case in which a transaction from a previous subpackage (either just submitted or already in mempool) is evicted. Mainly, since the coins created by the evicted transaction are cached in `m_view`, we don't realize the UTXO has disappeared until `CheckInputsFromMempoolAndCache` asserts that they exist. Also, the returned `PackageMempoolAcceptResult` reports that the transaction is in mempool even though it isn't anymore.
Fix this by not calling `LimitMempoolSize()` until the very end, and editing the results map with "mempool full" if things fall out.
Pointed out by instagibbs in faeed687e5 on top of the v3 PR.
ACKs for top commit:
instagibbs:
reACK https://github.com/bitcoin/bitcoin/pull/28251/commits/32c1dd1ad65af0ad4d36a56d2ca32a8481237e68
Tree-SHA512: 61e7f69db4712e5e5bfa27d037ab66bdd97f1bf60a8d9ffb96adb1f0609af012c810d681102ee5c7baec7b5fe8cb7c304a60c63ccc445d00d86a2b7f0e7ddb90
