Skip to content
master
Switch branches/tags
Code

Latest commit

 

Git stats

Files

Permalink
Failed to load latest commit information.
Type
Name
Latest commit message
Commit time
 
 
lib
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Sisyphus Logo

sh Template Tag

Build Status Dependencies Status npm Coverage Status Install Size Known Vulnerabilities

Provides a string template tag that makes it easy to compose sh and bash command strings by escaping dynamic values based on the context in which they appear.

Usage Example

const { sh, ShFragment } = require('sh-template-tag')

function echoCommand (a, b, c) {
  return sh`echo -- ${a} "${b}" 'c: ${c}'`
}

console.log(
  '%s',
  echoCommand(
    '; rm -rf / #',
    '$(cat /etc/shadow)',
    '\'"$(cat /etc/shadow)"\n#'))

/*

Logs the below which does not spawn any subshells:

echo -- '; rm -rf / #' "\$(cat /etc/shadow)" 'c: '"'"'"$(cat /etc/shadow)"
#'

*/

API

sh`...`

A tag handler that escapes values so that they contribute the literal characters, returning an ShFragment.

ShFragments are not escaped when they appear outside quotes.

ShFragment(str)

A TypedString subclass that specifies a fragment of a shell command suitable for embedding outside a quoted string and which has balanced delimiters.

ShFragments are mintable so to create one, do

const { Mintable } = require('node-sec-patterns')
const { ShFragment } = require('sh-template-tag')

const makeShFragment = Mintable.minterFor(ShFragment, (x) => String(x))

const myShFragment = makeShFragment('echo Hello;')

Caveats

"Library support for Safe Coding Practices"

Solving shell injection is a much harder problem than query injection since shell scripts tend to call other shell scripts, so properly escaping arguments to one script doesn't help if the script sloppily composes a sub-shell.

About

NPM package that provides a string template tag for safely composing sh/bash shell commands

Resources

License

Packages

No packages published