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			60 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			60 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
| # Trusted Computing
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| 
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| LinuxKit has support for using [Trusted Computing](http://trustedcomputinggroup.org) Platform Modules (tpm) chips.
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| 
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| Supporting tpm requires support at three levels:
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| 
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| * Hardware
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| * Kernel
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| * Software - The Trusted Computing Software Stack (TSS)
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| 
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| ## Hardware
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| You need to have a tpm chip installed in your computer to use tpm. Alternatively, you can use one of the virtual tpms implemented in software, provided that either:
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| 
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| * your kernel supports it
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| * your hardware virtualization platform supports it
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| 
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| ## Kernel
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| As of [PR 2234](https://github.com/linuxkit/linuxkit/pull/2234), the in-tree linux kernel modules that support tpm are shipped with LinuxKit by default.
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| 
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| The shipped modules support both tpm chip versions 1.2 and tpm 2.0.
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| 
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| ## Software
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| The software stack (TSS) functions differently between tpm versions 1.2 and 2.0.
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| 
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| ### tss 1.2
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| In tss 1.2, the character device `/dev/tpm0` is meant to be addresses only by a single process. All other clients are expected to communicate with this single client that handles multiplexing of requests and various other low-level functionality.
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| 
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| The single client normally used is [TrouSerS](https://sourceforge.net/p/trousers/trousers/). It creates a daemon, `tcsd`, that communicates with the character device (and via the character device and the kernel module to the actual tpm).
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| 
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| `tcsd` in turn listens on `localhost:30003` for tpm commands. All other clients are expected to communicate via tcp to `tcsd`.
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| 
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| LinuxKit provides the `linuxkit/tss` image which includes:
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| 
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| * `tcsd`
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| * the various `tpm_*` tools
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| 
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| To make a `tcsd` available to your LinuxKit image, just include it:
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| 
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| ```yml
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| services:
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|   - name: tss
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|     image: linuxkit/tss:<hash>
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| ```
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| 
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| For a full example, see [tpm.yml](../examples/tpm.yml)
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| 
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| ### tss 2.0
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| In tss 2.0, the character device `/dev/tpmrm0` can be addressed by as many processes, in parallel, as desired. All of the multiplexing and low-level services are built into the kernel module.
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| 
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| To use a tpm 2.0 device, you do **not** need any special tss container. You just need an container that:
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| 
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| 1. Bind-mounts `/dev` in
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| 2. Has your tools or libraries installed
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| 3. Talks directly to `/dev/tpmrm0`
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| 
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| 
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| The image `linuxkit/tss` ships with the version 1.2 `tcsd` and the `tpm_*` tools for tpm version 1.2. The tools for tpm version 2.0 `tpm2_*` and its attendant libs are _not_ included in the image.
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| 
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| We intend to release a tss 2.0 compatible image in the near future. In the meantime, nothing prevents you from using and compiling your own tss and including it in a LinuxKit image.
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