[Bug]: saltutil.runner drops privileges to the salt-api eauth user during orchestration

What happened?

saltutil.runner drops privileges to the salt-api eauth user during orchestration.
master_user_runas() reads opts["user"], which state.orchestrate overwrites with the publishing user. The pwd.getpwnam() guard added in #69600 only filters synthetic sudo values; PAM/LDAP eauth users are real local accounts, so master-side runners execute under the API caller's uid instead of the master daemon's.
Repro: master running as root, orchestration invoked via salt-api as a PAM user, orch contains a salt.runner state.
Symptom is obscured by a second bug: SyncClientMixin.low() references proc_fn in its finally block before it is assigned, so the real exception is replaced by UnboundLocalError: cannot access local variable 'proc_fn'.

Type of salt install

Official deb

Major version

3008.x

What supported OS are you seeing the problem on? Can select multiple. (If bug appears on an unsupported OS, please open a GitHub Discussion instead)

centos-stream-9, windows-2022, windows-2025, debian-13, amazonlinux-2023, rhel-9, ubuntu-22.04

salt --versions-report output

Salt Version:
            Salt: 3008.2

Python Version:
          Python: 3.14.6 (main, Jun 11 2026, 02:19:05) [GCC 11.2.0]

Dependency Versions:
            cffi: 2.0.0
        cherrypy: 18.10.0
    cryptography: 48.0.0
        dateutil: 2.9.0.post0
       docker-py: Not Installed
           gitdb: 4.0.12
       gitpython: 3.1.50
          Jinja2: 3.1.6
         libgit2: Not Installed
    looseversion: 1.3.0
        M2Crypto: Not Installed
            Mako: Not Installed
         msgpack: 1.1.2
    msgpack-pure: Not Installed
    mysql-python: Not Installed
       packaging: 24.0
       pycparser: 3.00
        pycrypto: 3.23.0
    pycryptodome: 3.23.0
          pygit2: Not Installed
    python-gnupg: 0.5.6
          PyYAML: 6.0.3
           PyZMQ: 27.1.0
          relenv: 0.22.14
           smmap: 5.0.2
         timelib: 0.3.0
         Tornado: 6.5.7
             ZMQ: 4.3.5

Salt Extensions:
 saltext.azurerm: 4.4.1

Salt Package Information:
    Package Type: onedir

System Versions:
            dist: ubuntu 22.04.5 jammy
          locale: utf-8
         machine: x86_64
         release: 6.8.0-1053-aws
          system: Linux
         version: Ubuntu 22.04.5 jammy

Start by tracing _master_user_runas() through state.orchestrate and the salt-api PAM/LDAP execution path, then inspect SyncClientMixin.low() and the guard introduced in #69600. Reproduce with a root master, a PAM eauth user, and an orchestration containing a salt.runner state. Done means master-side runners retain the daemon identity and the underlying exception is no longer replaced by UnboundLocalError.