HighFile-scopeC# Plug & play

Always Validate `ModelState.IsValid` in Controllers

Failing to check `ModelState.IsValid` before processing user input can result in invalid or unverified data being accepted.

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Why this matters

Failing to check `ModelState.IsValid` before processing user input can result in invalid or unverified data being accepted.

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

public async Task<IActionResult> Create(Movie movie) // Noncompliant: model validity check is missing
{
    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Prefer

public async Task<IActionResult> Create(Movie movie)
{
    if (!ModelState.IsValid)
    {
        return View(movie);
    }

    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

More snippets

Bad

public async Task<IActionResult> Create(Movie movie) // Noncompliant: model validity check is missing
{
    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Good

public async Task<IActionResult> Create(Movie movie)
{
    if (!ModelState.IsValid)
    {
        return View(movie);
    }

    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Related rules

From the same buckets as this rule.

Critical
Always sanitize user inputs
Check if user inputs are sanitized before being used in rendering or database queries. Unsanitized inputs can lead to injection vulnerabilities like XSS or SQL injection.
security-hardening
Critical
Always Verify Server Certificates in SSL/TLS Connections
Ensure that SSL/TLS certificate validation is always enabled to prevent Man-in-the-Middle (MitM) attacks.
security-hardening
Critical
Avoid modifying built-in prototypes
Detect modifications to built-in prototypes. Modifying built-in objects can lead to compatibility issues and unexpected behavior. Recommend creating helper functions instead.
maintainabilitysecurity-hardening

Bad vs. good

Side-by-side examples engineers can pattern-match during review.

Avoid

public async Task<IActionResult> Create(Movie movie) // Noncompliant: model validity check is missing
{
    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Prefer

public async Task<IActionResult> Create(Movie movie)
{
    if (!ModelState.IsValid)
    {
        return View(movie);
    }

    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

More snippets

Bad

public async Task<IActionResult> Create(Movie movie) // Noncompliant: model validity check is missing
{
    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Good

public async Task<IActionResult> Create(Movie movie)
{
    if (!ModelState.IsValid)
    {
        return View(movie);
    }

    _context.Movies.Add(movie);
    await _context.SaveChangesAsync();

    return RedirectToAction(titleof(Index));
}

Related rules

From the same buckets as this rule.

Critical

Always sanitize user inputs

Check if user inputs are sanitized before being used in rendering or database queries. Unsanitized inputs can lead to injection vulnerabilities like XSS or SQL injection.

security-hardening

Critical

Always Verify Server Certificates in SSL/TLS Connections

Ensure that SSL/TLS certificate validation is always enabled to prevent Man-in-the-Middle (MitM) attacks.

security-hardening

Critical

Avoid modifying built-in prototypes

Detect modifications to built-in prototypes. Modifying built-in objects can lead to compatibility issues and unexpected behavior. Recommend creating helper functions instead.

maintainabilitysecurity-hardening