From fde7c96b5cd44962fe08cdb8d23115ed51b30915 Mon Sep 17 00:00:00 2001 From: moneromooo-monero Date: Sun, 15 May 2022 11:50:28 +0000 Subject: [PATCH] wallet2: fix spurious reorg detection with untrusted nodes When forced to deal with an untrusted node, a wallet will quantize its current height to disguise the real height to the adversary, to try and minimize the daemon's ability to distinguish returning wallets. Daemons will thus return more blocks than the wallet needs, starting from earlier in the chain. These extra blocks will be disregarded by the wallet, which had already scanned them. However, for the purposes of reorg size detection, the wallet assumes all blocks the daemon sends are different, which is only correct if the wallet hasn't been coy, which is only the case for trusted daemons (which you should use). This causes an issue when the size of this "fake reorg" is above the sanity check threshold at which the wallet refuses a reorg. To fix this, the reorg size check is moved later on, when the reorg is about to actually happen, after the wallet has checked which blocks are actually different from the ones it expects. --- src/wallet/wallet2.cpp | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp index f4a5a5855..6885db953 100644 --- a/src/wallet/wallet2.cpp +++ b/src/wallet/wallet2.cpp @@ -2882,6 +2882,11 @@ void wallet2::process_parsed_blocks(uint64_t start_height, const std::vector m_max_reorg_depth, error::reorg_depth_error, + tr("reorg exceeds maximum allowed depth, use 'set max-reorg-depth N' to allow it, reorg depth: ") + + std::to_string(reorg_depth)); + detach_blockchain(current_index, output_tracker_cache); process_new_blockchain_entry(bl, blocks[i], parsed_blocks[i], bl_id, current_index, tx_cache_data, tx_cache_data_offset, output_tracker_cache); } @@ -3532,15 +3537,6 @@ void wallet2::refresh(bool trusted_daemon, uint64_t start_height, uint64_t & blo first = false; - if (!next_blocks.empty()) - { - const uint64_t expected_start_height = std::max(static_cast(m_blockchain.size()), uint64_t(1)) - 1; - const uint64_t reorg_depth = expected_start_height - std::min(expected_start_height, next_blocks_start_height); - THROW_WALLET_EXCEPTION_IF(reorg_depth > m_max_reorg_depth, error::reorg_depth_error, - tr("reorg exceeds maximum allowed depth, use 'set max-reorg-depth N' to allow it, reorg depth: ") + - std::to_string(reorg_depth)); - } - // if we've got at least 10 blocks to refresh, assume we're starting // a long refresh, and setup a tracking output cache if we need to if (m_track_uses && (!output_tracker_cache || output_tracker_cache->empty()) && next_blocks.size() >= 10)