[v17] fix: tsh label based commands always running serially#63611
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rosstimothy merged 1 commit intobranch/v17from Feb 9, 2026
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[v17] fix: tsh label based commands always running serially#63611rosstimothy merged 1 commit intobranch/v17from
rosstimothy merged 1 commit intobranch/v17from
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When using tsh ssh user@foo=bar uptime, the command is supposed to be run in parallel on all matching hosts unless Per-Session MFA is required, or the user has a restriction on the number of concurrent sessions. To determine if limits are enforced, tsh would list roles and take the maximum from all of them and add with a small buffer to prevent exceeding the limit. It turns out that this only works for users that have permissions to read Role resources. ListRoles does **not** return the roles of the current user if they do not have permissions to read roles like GetRole does. The result is that users that cannot read roles have all of the command run serially instead of in parallel even if they have _no_ connection limits in their roles. It looks like this has been the case for GetRoles and ListRoles since their inception. This has likely gone unnoticed because this is either a very uncommon workflow, or the users performing this regularly have read permissions for Role resources. There does exist an RPC that provides a user with all of the roles they are assigned regardless of their permissions: GetCurrentUserRoles. This RPC is now used in place of ListRoles when determining connection limits in tsh label based ssh.
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When using tsh ssh user@foo=bar uptime, the command is supposed to be run in parallel on all matching hosts unless Per-Session MFA is required, or the user has a restriction on the number of concurrent sessions. To determine if limits are enforced, tsh would list roles and take the maximum from all of them and add with a small buffer to prevent exceeding the limit. It turns out that this only works for users that have permissions to read Role resources. ListRoles does **not** return the roles of the current user if they do not have permissions to read roles like GetRole does. The result is that users that cannot read roles have all of the command run serially instead of in parallel even if they have _no_ connection limits in their roles. It looks like this has been the case for GetRoles and ListRoles since their inception. This has likely gone unnoticed because this is either a very uncommon workflow, or the users performing this regularly have read permissions for Role resources. There does exist an RPC that provides a user with all of the roles they are assigned regardless of their permissions: GetCurrentUserRoles. This RPC is now used in place of ListRoles when determining connection limits in tsh label based ssh.
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Backport #63555 to branch/v17
changelog: Fixed
tsh ssh user@foo=bar uptimefrom running serially if users did not haverole:readpermissions.