private static void SetHash(HttpContext context, string key, CSPHashType algorithm, string hash)
{
var hashes = context.Items[key] as List <string>;
if (hashes is null)
{
hashes = new List <string>();
context.Items[key] = hashes;
}
hashes.Add(GetSource(algorithm, hash));
}
private static string GetSource(CSPHashType algorithm, string hash)
{
switch (algorithm)
{
case CSPHashType.SHA256:
return($"'sha256-{hash}'");
case CSPHashType.SHA384:
return($"'sha384-{hash}'");
case CSPHashType.SHA512:
return($"'sha512-{hash}'");
default:
throw new InvalidOperationException($"Unknown CSP hash algorithm: {algorithm}");
}
}
/// <summary>
/// Create an instance of the required hashing algorithm
/// </summary>
/// <param name="algorithm">The CSP algorithm to create</param>
/// <returns>The hashing algorithm instance</returns>
public static HashAlgorithm Create(CSPHashType algorithm)
{
switch (algorithm)
{
case CSPHashType.SHA256:
return(CreateSHA256());
case CSPHashType.SHA384:
return(CreateSHA384());
case CSPHashType.SHA512:
return(CreateSHA512());
default:
throw new InvalidOperationException($"Unknown CSP Hash Type: {algorithm}");
}
}
/// <summary>
/// Adds a CSP hash to the collection of sources for style-src
/// </summary>
/// <param name="context">The <see cref="HttpContext"/> for the request</param>
/// <param name="algorithm">The algorithm used to calcualte the hash</param>
/// <param name="hash">The hash generated from the content</param>
public static void SetStylesCSPHash(this HttpContext context, CSPHashType algorithm, string hash)
{
SetHash(context, Constants.DefaultStylesHashKey, algorithm, hash);
}
