0c9ab0f8f8
167df7a98cnet: fix use-after-free with v2->v1 reconnection logic (Eugene Siegel) Pull request description: `CConnman::Stop()` resets `semOutbound`, yet `m_reconnections` is not cleared in `Stop`. Each `ReconnectionInfo` contains a `grant` member that points to the memory that `semOutbound` pointed to and `~CConnman` will attempt to access the grant field (memory that was already freed) when destroying `m_reconnections`. Fix this by calling `m_reconnections.clear()` in `CConnman::Stop()` and add appropriate annotations. I was able to reproduce the original issue https://github.com/bitcoin/bitcoin/issues/33615 with the following diff by randomly stopping my node while it was attempting to reconnect (and verified that this patch fixes the issue, at least in my ~40-50 runs): <details> <summary> diff </summary> ```diff diff --git a/src/net.cpp b/src/net.cpp index ef1c63044a..9c1d161d8b 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -1918,8 +1918,8 @@ void CConnman::DisconnectNodes() { LOCK(m_nodes_mutex); - const bool network_active{fNetworkActive}; - if (!network_active) { +// const bool network_active{fNetworkActive}; +// if (!network_active) { // Disconnect any connected nodes for (CNode* pnode : m_nodes) { if (!pnode->fDisconnect) { @@ -1927,7 +1927,7 @@ void CConnman::DisconnectNodes() pnode->fDisconnect = true; } } - } +// } // Disconnect unused nodes std::vector<CNode*> nodes_copy = m_nodes; @@ -1941,7 +1941,7 @@ void CConnman::DisconnectNodes() // Add to reconnection list if appropriate. We don't reconnect right here, because // the creation of a connection is a blocking operation (up to several seconds), // and we don't want to hold up the socket handler thread for that long. - if (network_active && pnode->m_transport->ShouldReconnectV1()) { + if (true) { reconnections_to_add.push_back({ .addr_connect = pnode->addr, .grant = std::move(pnode->grantOutbound), ``` </details> I'm curious to see if others can reproduce as well. ACKs for top commit: dergoegge: Code review ACK167df7a98cdarosior: utACK167df7a98cmzumsande: ACK167df7a98cTree-SHA512: 33fdfb110a7cdae182b5cd5400eea8a271308a62dd56491e0aef8865eff24a9ea908be74e4e2e2ee00ac1cb698e46f270f56dffffe34cf2cfd79e9b1079d6531
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