fix(postgres): return UnexpectedEof when server closes connection at SSLRequest - #4406
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abonander merged 1 commit intoSep 10, 2026
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…SSLRequest (transact-rs#4395) When a remote peer accepts the TCP socket and immediately closes it without responding to the 8-byte SSLRequest message, socket.read() returns 0 (EOF). Because the read byte count was discarded, the unwritten initial [0u8] buffer was matched against, reporting a fabricated Protocol("unexpected response from SSLRequest: 0x00") error. Check the returned read length and return an io::ErrorKind::UnexpectedEof error when 0 bytes are read, correctly identifying connection closure during the SSLRequest handshake, while preserving Protocol error reporting if the server actually transmits a wire 0x00 byte.
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Does your PR solve an issue?
fixes #4395
Is this a breaking change?
no
Description
When a remote server or intermediate proxy accepts the TCP socket and immediately drops or closes the connection before responding to the 8-byte
SSLRequest,socket.read(&mut &mut response[..])resolves to0bytes (EOF).Previously, the return count was discarded and the unwritten buffer byte
response[0](0u8) was matched against, reporting:Protocol("unexpected response from SSLRequest: 0x00")This misleadingly claimed the server sent an illegal
0x00protocol byte when no bytes were sent.This change inspects the read count
n. Whenn == 0, it returnsio::Error::from(io::ErrorKind::UnexpectedEof).into(), properly categorizing the failure as a transport I/O error (Error::Io).Regression Tests
Includes unit tests in
sqlx-postgres/src/connection/tls.rsverifying the EOF behavior on SSLRequest (test_request_upgrade_eof), which fails before this fix and passes afterwards, as well as confirmingError::Protocolis preserved if the server transmits an actual wire0x00byte (test_request_upgrade_wire_null_byte), along with tests forb'S',b'N', and unexpected byte values.