Avoid using unsanitized user input with sendFile

Documentos > Code Analysis > Static Analysis Rules > Avoid using unsanitized user input with sendFile

This page is not yet available in Spanish. We are working on its translation.
If you have any questions or feedback about our current translation project, feel free to reach out to us!

Metadata

ID: typescript-express/external-filename-upload

Language: TypeScript

Severity: Warning

Category: Security

CWE: 73

Description

Using unsanitized user input in a sendFile method can allow attackers to access unintended resources.

Set the root option directly in your sendFile options will make this rule not report a violation.

Learn More

Express sendFile API reference

Non-Compliant Code Examples

app.post("/upload", (req: Request, res: Response) => {
    res.sendFile(req.params.filename)

    res.sendFile(req.params.filename, { maxAge: 0 })

    res.sendFile(req.params.filename, { maxAge: 0 }, (err) => console.log(err))
})

Compliant Code Examples

app.post("/upload", (req: Request, res: Response) => {
    res.sendFile("foo")

    const options = { maxAge: 0, root: path.join(__dirname, "upload") }

    res.sendFile(req.params.filename, options)
    res.sendFile(req.params.filename, { maxAge: 0, root: path.join(__dirname, "upload") })

    res.sendFile(req.params.filename, options, (err) => console.log(err))
    res.sendFile(req.params.filename, { maxAge: 0, root: path.join(__dirname, "upload") }, (err) => console.log(err))
})