pageant: fall back to GetUserNameA when GetUserNameExA fails - #726
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GetUserNameExA(NameUserPrincipal) requires a UPN, which does not exist on non-domain-joined Windows machines (standalone/workgroup). On such machines the API fails with ERROR_NONE_MAPPED (0x80070534), preventing any named-pipe connection to Pageant. The original PuTTY Pageant falls back to GetUserNameA in this case, but the Rust port was missing this fallback. Instead, fall back to the USERNAME environment variable, which provides the SAM account name and matches what GetUserNameA would return on local accounts. Fixes: inability to connect to Pageant on non-domain Windows setups
This was referenced Aug 13, 2026
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Can confirm on Windows 11 with a local (non-domain) account: GetUserNameExA(NameUserPrincipal) fails with 0x80070534, so the transport never gets a pipe name even though the pipe is right there as The USERNAME fallback would've produced the correct name for us. Hit this while evaluating russh 0.62.6 for a desktop app. +1 for merging. |
Eugeny
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Thanks - I've updated it to fall back to GetUserNameA to match what putty is actually doing |
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@all-contributors add @cwatanab for code |
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Problem
GetUserNameExA(NameUserPrincipal)requires a UPN (User Principal Name), which does not exist on non-domain-joined Windows machines (standalone/workgroup). On such machines the API fails withERROR_NONE_MAPPED(0x80070534), preventing any named-pipe connection to a running Pageant instance.This affects applications like DBX (Database Explorer) and the
pageantcrate itself.Root Cause
The original PuTTY Pageant (C implementation) falls back to
GetUserNameAwhenGetUserNameExAfails. The code comment acknowledges this but the Rust port chose not to implement the fallback, under the assumption that all modern Windows versions supportGetUserNameExA. However, even on modern Windows 10/11, a non-domain-joined machine has no UPN configured, and the API call fails.Fix
Fall back to the
USERNAMEenvironment variable whenGetUserNameExA(NameUserPrincipal)fails. This provides the SAM account name, which matches what the original PuTTY Pageant'sGetUserNameAfallback would return on local accounts.Testing
GetUserNameExA(NameUserPrincipal)consistently fails withERROR_NONE_MAPPEDUSERNAMEenv var contains the correct SAM account nameThis is consistent with how the reference PuTTY Pageant implementation handles this edge case.