open-nomad/helper/subproc/doc.go
Seth Hoenig 51a2212d3d
client: sandbox go-getter subprocess with landlock (#15328)
* client: sandbox go-getter subprocess with landlock

This PR re-implements the getter package for artifact downloads as a subprocess.

Key changes include

On all platforms, run getter as a child process of the Nomad agent.
On Linux platforms running as root, run the child process as the nobody user.
On supporting Linux kernels, uses landlock for filesystem isolation (via go-landlock).
On all platforms, restrict environment variables of the child process to a static set.
notably TMP/TEMP now points within the allocation's task directory
kernel.landlock attribute is fingerprinted (version number or unavailable)
These changes make Nomad client more resilient against a faulty go-getter implementation that may panic, and more secure against bad actors attempting to use artifact downloads as a privilege escalation vector.

Adds new e2e/artifact suite for ensuring artifact downloading works.

TODO: Windows git test (need to modify the image, etc... followup PR)

* landlock: fixup items from cr

* cr: fixup tests and go.mod file
2022-12-07 16:02:25 -06:00

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Go

// Package subproc provides helper utilities for executing the Nomad binary as
// a child process of the Nomad agent.
//
// The main entrypoint is the Do function, in which the given MainFunc will be
// executed as a sub-process if the first argument matches the subcommand.
//
// Context can be used to create a context.Context object with a given timeout,
// and is expected to be used in conjunction with SetExpiration which uses the
// context's termination to forcefully terminate the child process if it has not
// exited by itself.
package subproc