feat: Introduce shell metacharacter escaping for exec

[servusdei2018]

In order to mitigate potential security vulnerabilities arising from shell injection attacks, this PR introduces a function to escape shell metacharacters which may be present in command-line arguments.

It's worth noting that two potential vulnerabilities still exist in

nvidia-container-toolkit/tools/container/nvidia-toolkit/run.go

Lines 249 to 252 in 973a663

	cmdline := fmt.Sprintf("%v setup %v %v\n", o.runtime, o.runtimeArgs, toolkitDir)
	//nolint:gosec // TODO: Can we harden this so that there is less risk of command injection
	cmd := exec.Command("sh", "-c", cmdline)

and

nvidia-container-toolkit/tools/container/nvidia-toolkit/run.go

Lines 275 to 278 in 973a663

	cmdline := fmt.Sprintf("%v cleanup %v %v\n", o.runtime, o.runtimeArgs, toolkitDir)
	//nolint:gosec // TODO: Can we harden this so that there is less risk of command injection
	cmd := exec.Command("sh", "-c", cmdline)

where the string o.runtimeArgs is directly interpolated into cmdline, leaving it susceptible to injection attacks. To address this, a more comprehensive solution would involve reimplementing o.runtimeArgs as []string, allowing for proper sanitization using the introduced oci.Escape() function; however, this likely involves a breaking change.

[servusdei2018]

cc @elezar

[elezar]

My one question would be whether the logic that we're implementing here exists in some third-pary package somewhere. I'm sure that runc for example needs to also check the arguments that are passed to its hooks.

[servusdei2018]

Hmm I believe I did look at runc and couldn't find the exact logic they used. I also looked at Docker and they use shellescape internally.