Skip to content

Commit

Permalink
[windows_kext] Improve documentation
Browse files Browse the repository at this point in the history
  • Loading branch information
vlabo committed Oct 18, 2024
1 parent d26ab22 commit 4907ae8
Show file tree
Hide file tree
Showing 3 changed files with 60 additions and 16 deletions.
32 changes: 18 additions & 14 deletions windows_kext/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -5,45 +5,49 @@ Implementation of Safing's Portmaster Windows kernel extension in Rust.

- [Driver](driver/README.md) -> entry point.
- [WDK](wdk/README.md) -> Windows Driver Kit interface.
- [Packet Path](PacketDoc.md) -> Detiled documentation of what happens to a packet when it enters the kernel extension.
- [Packet Path](PacketFlow.md) -> Detailed documentation of what happens to a packet when it enters the kernel extension.
- [Release](release/README.md) -> Guide how to do a release build
- [Windows Filtering Platform - MS](https://learn.microsoft.com/en-us/windows-hardware/drivers/network/roadmap-for-developing-wfp-callout-drivers) -> The driver is build on top of WFP.


### Building

The Windows Portmaster Kernel Extension is currently only developed and tested for the amd64 (64-bit) architecture.

__Prerequesites:__
__Prerequirements:__

- Visual Studio 2022
- Install C++ and Windows 11 SDK (22H2) components
- Add `link.exe` and `signtool` in the PATH
- Rust
- Windows Driver Kit
- https://learn.microsoft.com/en-us/windows-hardware/drivers/download-the-wdk
- Rust (Can be separate machine)
- https://www.rust-lang.org/tools/install
- Cargo make(optional)
- https://github.com/sagiegurari/cargo-make

__Setup Test Signing:__

In order to test the driver on your machine, you will have to test sign it (starting with Windows 10).
> Not recommended for a work machine. Usually done on virtual machine dedicated for testing.
In order to test the driver on your machine, you will have to sign it (starting with Windows 10).

Create a new certificate for test signing:

:: Open a *x64 Free Build Environment* console as Administrator.
```ps
# Open a *x64 Free Build Environment* console as Administrator.
:: Run the MakeCert.exe tool to create a test certificate:
# Run the MakeCert.exe tool to create a test certificate:
MakeCert -r -pe -ss PrivateCertStore -n "CN=DriverCertificate" DriverCertificate.cer
:: Install the test certificate with CertMgr.exe:
# Install the test certificate with CertMgr.exe:
CertMgr /add DriverCertificate.cer /s /r localMachine root

```

Enable Test Signing on the dev machine:

:: Before you can load test-signed drivers, you must enable Windows test mode. To do this, run this command:
```ps
# Before you can load test-signed drivers, you must enable Windows test mode. To do this, run this command:
Bcdedit.exe -set TESTSIGNING ON
:: Then, restart Windows. For more information, see The TESTSIGNING Boot Configuration Option.

# Then, restart Windows. For more information, see The TESTSIGNING Boot Configuration Option.
```

__Build driver:__

Expand Down
39 changes: 39 additions & 0 deletions windows_kext/protocol/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -2,3 +2,42 @@

Defines protocol that communicates with `kextinterface` / Portmaster.

The crate implements simple binary protocol. The communications is designed to be concurrent stream of packets.
Input and output work independent of each other.
- Pormtaster can read multiple info packets from the queue with single read request.
- Portmaster can write one command packet to the kernel extension with single write request.

## Info: Kext -> Portmaster

Info is a packet that sends information/events from the kernel extension to portmaster.
For example: `new connection`, `end of connection`, `bandwidth stats` ... check `info.rs` for full list.

The Info packet contains a header that is 5 bytes
```
0 1 2 3 4
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Info Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
```
> Note that one tick mark represents one bit position.
The header is followed by the info data.


## Command: Portmaster -> Kext

Command is a packet that portmaster sends to the kernel extension.
For example: `verdict response`, `shutdown`, `get logs` ... check `command.rs` for full list.

The header of the command packet is 1 byte
```
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
| Command Type |
+-+-+-+-+-+-+-+-+
```
> Note that one tick mark represents one bit position.
Rest of the packet will be the payload of the command (some commands don't contain payload just the command type).

5 changes: 3 additions & 2 deletions windows_kext/release/README.md
Original file line number Diff line number Diff line change
Expand Up @@ -7,12 +7,13 @@

### Generate the cab file
- Copy the zip and extract it on a windows machine.
* Some version Visual Studio needs to be installed.
* Visual Studio 2022 and WDK need to be installed.
- From VS Command Prompt / PowerShell run:
```
cd kext_release_v.../
./build_cab.bat
```
> Script is written for VS `$SDK_Version = "10.0.22621.0"`. If different version is used update the script.
3. Sing the cab file

Expand All @@ -25,4 +26,4 @@ cd kext_release_v.../
- Wait for the process to finish, download the `.zip`.

The zip will contain the release files.
> Optionally sign the .sys file.
> Optionally sign the .sys file, with company certificate.

0 comments on commit 4907ae8

Please sign in to comment.