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32 lines
1.5 KiB
Markdown
32 lines
1.5 KiB
Markdown
# Be cautious when working with child processes
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### One Paragraph Explainer
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As great as child processes are, they should be used with caution. Passing in user input must be sanitized, if not avoided at all.
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The dangers of unsanitized input executing system-level logic are unlimited, reaching from remote code execution to the exposure of
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sensitive system data and even data loss. A check list of preparations could look like this
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- avoid user input in every case, otherwise validate and sanitize it
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- limit the privileges of the parent and child processes using user/group identities
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- run your process inside of an isolated environment to prevent unwanted side-effects if the other preparations fail
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### Code example: Dangers of unsanitized child process executions
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```javascript
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const { exec } = require('child_process');
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...
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// as an example, take a script that takes two arguments, one of them is unsanitized user input
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exec('"/path/to/test file/someScript.sh" --someOption ' + input);
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// -> imagine what could happen if the user simply enters something like '&& rm -rf --no-preserve-root /'
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// you'd be in for an unwanted surprise
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```
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### Additional resources
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From the Node.js child process [documentation](https://nodejs.org/dist/latest-v8.x/docs/api/child_process.html#child_process_child_process_exec_command_options_callback):
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> Never pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.
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