| --- | --- |
| `setup-windows.bat` | Entry point. Runs the winget installs, then launches the elevated half and prints its log, then runs the non-elevated script. |
| `setup-windows-no-uac.ps1` | The non-elevated, per-user half: WinMerge and BinSkim on the user `PATH`, and the global git config (identity, plus `core.sshCommand`). Can also be run directly from an ordinary prompt. |
-| `setup-windows-with-uac.ps1` | The elevated half, started via UAC by the batch file. Enables `ssh-agent`, installs the OpenSSH Client and Server capabilities and starts `sshd`, unpacks the `rsync-windows` release zip for this architecture (`rsync.exe` plus the `ssh.exe` it runs) into `C:\Tools\rsync` on the machine `PATH`, then installs Visual Studio 2022 Community with the required components, the WDK, and the Windows Performance Toolkit, and finally grants one ordinary account the rights to collect ETW traces without elevation. Can also be run directly from an Administrator prompt — pass `-TraceUser DOMAIN\user` to say who gets those rights, and `-EtwRightsOnly` to do that step alone. |
+| `setup-windows-with-uac.ps1` | The elevated half, started via UAC by the batch file. Enables `ssh-agent`, installs the OpenSSH Client and Server capabilities and starts `sshd`, unpacks the `rsync-windows` release zip for this architecture (`rsync.exe` plus the `ssh.exe` it runs) into `C:\Tools\rsync` on the machine `PATH`, then installs Visual Studio 2022 Community with the required components, the WDK, and the Windows Performance Toolkit, and reports whether Intel VTune Profiler is present. It also puts one ordinary account into `Performance Log Users`, so it can run user-mode ETW sessions unelevated. Can also be run directly from an Administrator prompt — pass `-TraceUser DOMAIN\user` to name that account, and `-EtwRightsOnly` to do that step alone. |
| `setup-windows-7-test-env.bat` | Prepares a **Windows 7 VM** as a test target driven from the host by `VBoxManage guestcontrol`. Copy it into the guest and run it there; it is idempotent, so re-run it after any snapshot restore. The per-user half needs no UAC (crash-dialog suppression, no screen blanking, a staging directory, the shared folder on `Z:`); the machine-wide half is skipped with a notice unless run elevated inside the guest. It then reports what the box can actually test: DWM composition, printers, audio capture devices. |
## Usage
— the Linux driver can be handed to a `vtune` group, but on Windows the
documented answer is to run as administrator.
-- **Tracing without a UAC prompt.** `xperf` and `wpr` fail for a standard user in
- two different ways, because two different things are missing:
+- **User-mode ETW tracing without a UAC prompt — and the kernel logger's hard
+ limit.** Out of the box a standard user cannot start *any* event tracing
+ session, not even a user-mode one naming a single provider:
```text
- xperf -on base -> NT Kernel Logger: Access is denied. (0x5)
- wpr -start GeneralProfile -> Failed to enable the policy to profile system performance.
+ xperf -start T -on Microsoft-Windows-Kernel-Process -f trace.etl
+ -> Access is denied. (0x5)
```
- Three separate things are in the way, and all three have to be dealt with:
-
- 1. Creating or controlling *any* ETW session — even a user-mode one naming a
- single provider — is checked against the security descriptor ETW keeps per
- provider GUID under `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`,
- whose **default** grants the session-control rights to SYSTEM,
- Administrators, the service accounts and `BUILTIN\Performance Log Users`,
- and to nobody else.
- 2. Switching on the *kernel* provider needs the `SeSystemProfilePrivilege` user
- right ("Profile system performance"), held by default only by
- Administrators and `NT SERVICE\WdiServiceHost` — that is the one `wpr`
- names.
- 3. The kernel logger is not covered by that default descriptor.
- `SystemTraceControlGuid` — the session both `xperf -on` and `wpr` drive —
- carries an explicit one that does not mention Performance Log Users. With
- 1 and 2 in place a user-mode session starts and the privilege is held, and
- `xperf -on base` *still* answers "NT Kernel Logger: Access is denied" while
- `wpr`'s error changes to a bare `0x80070005`; even reading that descriptor
- comes back access-denied, which is the tell. So an ACE for the group is
- added with `EventAccessControl`, `TRACELOG_ACCESS_KERNEL_LOGGER` included.
-
- The privilege and the ACE both go to the **group**, and the account then goes
- into the group, so membership alone is the switch and enabling another account
- afterwards is just `net localgroup "Performance Log Users" <user> /add`.
- `SeDebugPrivilege` is deliberately *not* granted: CPU sampling and stack walks
- of your own processes do not need it, and it is equivalent to handing out
- administrator. Worth being clear about the cost: a member of that group can
- capture system-wide kernel traces — process, image, file and registry activity
- across every account on the box, paths and command lines included.
-
- Two consequences worth knowing. A privilege and a group membership are both
- read into the access token **at logon**, so the account must sign out and back
- in for 1 and 2 — any new logon does it, and an `ssh` login into the box is the
- quick way to check without dropping the desktop. The ACE in 3 is machine state
- instead, and a logon does nothing for it: ETW reads these descriptors into a
- cache, so it takes a **reboot** — with the ACE written and readable, `xperf -on
- base` was still denied from a fresh shell on the running system. Plan on both
- on a first run. And this only
- helps a **non-admin** account: UAC hands an administrator a filtered token
- carrying just five harmless privileges, so an admin's ordinary shell still
- cannot trace however the policy reads. Verify from the target account,
- unelevated:
-
- ```powershell
- whoami /priv | findstr SeSystemProfilePrivilege
- xperf -on base ; xperf -stop C:\Temp\trace.etl
- ```
-
- Analysis never needed any of this — `wpa.exe` opens an existing `.etl` as a
- plain user. This is only about collection.
-
- The rights step runs **first** in the elevated half, and `-EtwRightsOnly` runs
- it and nothing else. It is seconds of LSA and registry work where a full run is
- dominated by the three Visual Studio passes, which take minutes even with
- nothing to do:
+ Session control is checked against the security descriptor ETW keeps per
+ provider GUID under `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`, whose
+ default grants those rights to SYSTEM, Administrators, the service accounts and
+ `BUILTIN\Performance Log Users` — and to nobody else. So the elevated half puts
+ the account named by `-TraceUser` into that group, and the command above then
+ works unelevated; enabling another account later is just
+ `net localgroup "Performance Log Users" <user> /add`. Membership is read into
+ the access token **at logon**, so sign out and back in first — any new logon
+ does it, and an `ssh` login into the box is the quick way to check without
+ dropping the desktop.
+
+ **Kernel traces are not available this way, and cannot be made to be.**
+ `xperf -on base` and `wpr -start` drive the *NT Kernel Logger*, which is
+ reserved for Administrators and LocalSystem — Microsoft documents Performance
+ Log Users access as explicitly not extending to it. That was measured rather
+ than assumed, and the negative result is recorded here so nobody repeats the
+ experiment: with the account in the group, `SeSystemProfilePrivilege` ("Profile
+ system performance") granted to that group, and an explicit ACE giving the
+ group `TRACELOG_ACCESS_KERNEL_LOGGER` on `SystemTraceControlGuid` — all three
+ in place, across a reboot — `xperf -on base` still answered `NT Kernel Logger:
+ Access is denied. (0x5)`. It is not a check an ACE overrides. The privilege
+ grant and the ACE were dropped again rather than left on the box earning
+ nothing: CPU sampling and whole-system traces are elevated work, with `xperf`,
+ `wpr` or VTune from an Administrator prompt.
+
+ Analysis was never affected — `wpa.exe` opens an existing `.etl` as a plain
+ user. This is only about collection.
+
+ The step runs **first** in the elevated half, and `-EtwRightsOnly` runs it and
+ nothing else, which matters because a full run is dominated by the three Visual
+ Studio passes that take minutes even with nothing to do:
```powershell
Start-Process powershell -Verb RunAs -ArgumentList '-NoProfile','-ExecutionPolicy','Bypass',
'-File','<repo>\setup-windows-with-uac.ps1','-TraceUser','DOMAIN\user','-EtwRightsOnly'
```
+
+ If you ran an earlier revision of this script, it left both of the grants above
+ on the box. Undo the privilege in `secpol.msc` > Local Policies > User Rights
+ Assignment > "Profile system performance" by removing Performance Log Users.
+ The ACEs sit in the `{9e814aad-3204-11d2-9a82-006008a86939}` value under
+ `HKLM\SYSTEM\CurrentControlSet\Control\WMI\Security`: strip the `LU` entries
+ from that descriptor rather than deleting the value, which also carries entries
+ for SYSTEM, Administrators and two service accounts.
- The scripts were extracted from a native Windows project, so the component
selection is tuned for that: Spectre-mitigated runtimes, the v141/XP toolset,
and driver-kit headers. Trim the component lists in the `.ps1` if you don't
vilimpoc.org / repos / dotfiles / blobdiff