DocSpace-buildtools/common/services/ASC.ApiSystem/Classes/AuthHandler.cs

// (c) Copyright Ascensio System SIA 2010-2022
//
// This program is a free software product.
// You can redistribute it and/or modify it under the terms
// of the GNU Affero General Public License (AGPL) version 3 as published by the Free Software
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// to the effect that Ascensio System SIA expressly excludes the warranty of non-infringement of
// any third-party rights.
//
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For details, see
// the GNU AGPL at: http://www.gnu.org/licenses/agpl-3.0.html
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// content are licensed under the terms of the Creative Commons Attribution-ShareAlike 4.0
// International. See the License terms at http://creativecommons.org/licenses/by-sa/4.0/legalcode


namespace ASC.ApiSystem.Classes;

[Scope]
public class AuthHandler : AuthenticationHandler<AuthenticationSchemeOptions>
{
    public AuthHandler(IOptionsMonitor<AuthenticationSchemeOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock) :
        base(options, logger, encoder, clock)
    {
    }

    public AuthHandler(
        IOptionsMonitor<AuthenticationSchemeOptions> options,
        ILoggerFactory logger,
        UrlEncoder encoder,
        ISystemClock clock,
        IConfiguration configuration,
        ILogger<AuthHandler> log,
        ApiSystemHelper apiSystemHelper,
        MachinePseudoKeys machinePseudoKeys,
        IHttpContextAccessor httpContextAccessor) :
        base(options, logger, encoder, clock)
    {
        Configuration = configuration;

        Log = log;

        ApiSystemHelper = apiSystemHelper;
        MachinePseudoKeys = machinePseudoKeys;
        HttpContextAccessor = httpContextAccessor;
    }

    private ILogger<AuthHandler> Log { get; }

    private IConfiguration Configuration { get; }

    private ApiSystemHelper ApiSystemHelper { get; }
    private MachinePseudoKeys MachinePseudoKeys { get; }
    private IHttpContextAccessor HttpContextAccessor { get; }

    protected override Task<AuthenticateResult> HandleAuthenticateAsync()
    {
        if (Convert.ToBoolean(Configuration[Scheme.Name] ?? "false"))
        {
            Log.LogDebug("Auth for {0} skipped", Scheme.Name);

            return Task.FromResult(AuthenticateResult.Success(new AuthenticationTicket(Context.User, new AuthenticationProperties(), Scheme.Name)));
        }

        try
        {
            Context.Request.Headers.TryGetValue("Authorization", out var headers);

            var header = headers.FirstOrDefault();

            if (string.IsNullOrEmpty(header))
            {
                Log.LogDebug("Auth header is NULL");

                return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.Unauthorized))));
            }

            var substring = "ASC";

            if (header.StartsWith(substring, StringComparison.InvariantCultureIgnoreCase))
            {
                var splitted = header.Substring(substring.Length).Trim().Split(':', StringSplitOptions.RemoveEmptyEntries);

                if (splitted.Length < 3)
                {
                    Log.LogDebug("Auth failed: invalid token {0}.", header);

                    return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.Unauthorized))));
                }

                var pkey = splitted[0];
                var date = splitted[1];
                var orighash = splitted[2];

                Log.LogDebug("Variant of correct auth:" + ApiSystemHelper.CreateAuthToken(pkey));

                if (!string.IsNullOrWhiteSpace(date))
                {
                    var timestamp = DateTime.ParseExact(date, "yyyyMMddHHmmss", CultureInfo.InvariantCulture);

                    var trustInterval = TimeSpan.FromMinutes(Convert.ToDouble(Configuration["auth:trust-interval"] ?? "5"));

                    if (DateTime.UtcNow > timestamp.Add(trustInterval))
                    {
                        Log.LogDebug("Auth failed: invalid timesatmp {0}, now {1}.", timestamp, DateTime.UtcNow);

                        return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.Forbidden))));
                    }
                }

                var skey = MachinePseudoKeys.GetMachineConstant();
                using var hasher = new HMACSHA1(skey);
                var data = string.Join("\n", date, pkey);
                var hash = hasher.ComputeHash(Encoding.UTF8.GetBytes(data));

                if (WebEncoders.Base64UrlEncode(hash) != orighash && Convert.ToBase64String(hash) != orighash)
                {
                    Log.LogDebug("Auth failed: invalid token {0}, expect {1} or {2}.", orighash, WebEncoders.Base64UrlEncode(hash), Convert.ToBase64String(hash));

                    return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.Forbidden))));
                }
            }
            else
            {
                Log.LogDebug("Auth failed: invalid auth header. Sheme: {0}, parameter: {1}.", Scheme.Name, header);

                return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.Forbidden))));
            }
        }
        catch (Exception ex)
        {
            Log.LogError(ex, "auth error");

            return Task.FromResult(AuthenticateResult.Fail(new AuthenticationException(nameof(HttpStatusCode.InternalServerError))));
        }
        var identity = new ClaimsIdentity(Scheme.Name);

        Log.LogInformation("Auth success {0}", Scheme.Name);
        if (HttpContextAccessor?.HttpContext != null) HttpContextAccessor.HttpContext.User = new CustomClaimsPrincipal(new ClaimsIdentity(Scheme.Name), identity);
        return Task.FromResult(AuthenticateResult.Success(new AuthenticationTicket(Context.User, new AuthenticationProperties(), Scheme.Name)));
    }
}