abstract_tcp_server2: add missing return
What the developer wrote
Authored by selsta
abstract_tcp_server2: add missing return
What changed, and why it matters
A single missing 'return' statement was added in Monero's networking code. Without it, after starting an asynchronous network write, the function could continue executing additional code that was only meant to run when no write was started. This could lead to unexpected behavior such as duplicate write operations, connection state corruption, or a crash, but the exact security impact is unclear from the tiny patch alone.
Review the complete function around the patched location to confirm whether the fall-through could cause a double write, use-after-free, or other state corruption. If the project maintains a bug bounty or security contact, consider treating this as a low-to-moderate networking bug pending further analysis. Users should update to the fixed commit once a release is available.
Security signals we found
Missing control-flow return after initiating asynchronous I/O
Potential violation of connection send-state invariants
Network-facing code path in Monero P2P server implementation
Evidence from the diff
In contrib/epee/include/net/abstract_tcp_server2.inl, a lambda calls start_write() to initiate an async send and then falls through because the ‘return’ was missing. The surrounding context suggests the code after the lambda was intended only for the case where start_write() was not called. The missing return therefore causes the post-write code path to execute immediately after scheduling the async write, potentially violating invariants in the connection’s send state machine. The patch is one line and does not show the full function, so the precise bug class (use-after-free, double-write, logic bug) cannot be determined from the diff alone.
Changed components
contrib/epee/include/net/abstract_tcp_server2.inlMonero P2P networking layer (abstract_tcp_server2)Inspect captured patch +1 / −0
diff --git a/contrib/epee/include/net/abstract_tcp_server2.inl b/contrib/epee/include/net/abstract_tcp_server2.inl
index d344119..736583b 100644
--- a/contrib/epee/include/net/abstract_tcp_server2.inl
+++ b/contrib/epee/include/net/abstract_tcp_server2.inl
@@ -518,6 +518,7 @@ namespace net_utils
start_write();
}
});
+ return;
}
}
Why this scored 44/100
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