// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/ssl/ssl_policy.h"

#include "base/bind.h"
#include "base/base_switches.h"
#include "base/command_line.h"
#include "base/memory/singleton.h"
#include "base/string_piece.h"
#include "base/string_util.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/browser/renderer_host/render_view_host_impl.h"
#include "content/browser/site_instance_impl.h"
#include "content/browser/ssl/ssl_cert_error_handler.h"
#include "content/browser/ssl/ssl_request_info.h"
#include "content/browser/web_contents/navigation_entry_impl.h"
#include "content/browser/web_contents/web_contents_impl.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/common/ssl_status.h"
#include "content/public/common/url_constants.h"
#include "net/base/ssl_info.h"
#include "webkit/glue/resource_type.h"

using content::NavigationEntryImpl;
using content::SiteInstance;
using content::SSLStatus;

namespace {

static const char kDot = '.';

static bool IsIntranetHost(const std::string& host) {
  const size_t dot = host.find(kDot);
  return dot == std::string::npos || dot == host.length() - 1;
}

}  // namespace

SSLPolicy::SSLPolicy(SSLPolicyBackend* backend)
    : backend_(backend) {
  DCHECK(backend_);
}

void SSLPolicy::OnCertError(SSLCertErrorHandler* handler) {
  // First we check if we know the policy for this error.
  net::CertPolicy::Judgment judgment =
      backend_->QueryPolicy(handler->ssl_info().cert,
                            handler->request_url().host());

  if (judgment == net::CertPolicy::ALLOWED) {
    handler->ContinueRequest();
    return;
  }

  // The judgment is either DENIED or UNKNOWN.
  // For now we handle the DENIED as the UNKNOWN, which means a blocking
  // page is shown to the user every time he comes back to the page.

  switch (handler->cert_error()) {
    case net::ERR_CERT_COMMON_NAME_INVALID:
    case net::ERR_CERT_DATE_INVALID:
    case net::ERR_CERT_AUTHORITY_INVALID:
    case net::ERR_CERT_WEAK_SIGNATURE_ALGORITHM:
    case net::ERR_CERT_WEAK_KEY:
      OnCertErrorInternal(handler, !handler->fatal(), handler->fatal());
      break;
    case net::ERR_CERT_NO_REVOCATION_MECHANISM:
      // Ignore this error.
      handler->ContinueRequest();
      break;
    case net::ERR_CERT_UNABLE_TO_CHECK_REVOCATION:
      // We ignore this error but will show a warning status in the location
      // bar.
      handler->ContinueRequest();
      break;
    case net::ERR_CERT_CONTAINS_ERRORS:
    case net::ERR_CERT_REVOKED:
    case net::ERR_CERT_INVALID:
    case net::ERR_CERT_NOT_IN_DNS:
      OnCertErrorInternal(handler, false, handler->fatal());
      break;
    default:
      NOTREACHED();
      handler->CancelRequest();
      break;
  }
}

void SSLPolicy::DidRunInsecureContent(NavigationEntryImpl* entry,
                                      const std::string& security_origin) {
  if (!entry)
    return;

  SiteInstance* site_instance = entry->site_instance();
  if (!site_instance)
      return;

  backend_->HostRanInsecureContent(GURL(security_origin).host(),
                                   site_instance->GetProcess()->GetID());
}

void SSLPolicy::OnRequestStarted(SSLRequestInfo* info) {
  // TODO(abarth): This mechanism is wrong.  What we should be doing is sending
  // this information back through WebKit and out some FrameLoaderClient
  // methods.

  if (net::IsCertStatusError(info->ssl_cert_status()))
    backend_->HostRanInsecureContent(info->url().host(), info->child_id());
}

void SSLPolicy::UpdateEntry(NavigationEntryImpl* entry,
                            WebContentsImpl* web_contents) {
  DCHECK(entry);

  InitializeEntryIfNeeded(entry);

  if (!entry->GetURL().SchemeIsSecure())
    return;

  // An HTTPS response may not have a certificate for some reason.  When that
  // happens, use the unauthenticated (HTTP) rather than the authentication
  // broken security style so that we can detect this error condition.
  if (!entry->GetSSL().cert_id) {
    entry->GetSSL().security_style = content::SECURITY_STYLE_UNAUTHENTICATED;
    return;
  }

  if (!(entry->GetSSL().cert_status & net::CERT_STATUS_COMMON_NAME_INVALID)) {
    // CAs issue certificates for intranet hosts to everyone.  Therefore, we
    // mark intranet hosts as being non-unique.
    if (IsIntranetHost(entry->GetURL().host())) {
      entry->GetSSL().cert_status |= net::CERT_STATUS_NON_UNIQUE_NAME;
    }
  }

  if (net::IsCertStatusError(entry->GetSSL().cert_status)) {
    // Minor errors don't lower the security style to
    // SECURITY_STYLE_AUTHENTICATION_BROKEN.
    if (!net::IsCertStatusMinorError(entry->GetSSL().cert_status)) {
      entry->GetSSL().security_style =
          content::SECURITY_STYLE_AUTHENTICATION_BROKEN;
    }
    return;
  }

  SiteInstance* site_instance = entry->site_instance();
  // Note that |site_instance| can be NULL here because NavigationEntries don't
  // necessarily have site instances.  Without a process, the entry can't
  // possibly have insecure content.  See bug http://crbug.com/12423.
  if (site_instance &&
      backend_->DidHostRunInsecureContent(
          entry->GetURL().host(), site_instance->GetProcess()->GetID())) {
    entry->GetSSL().security_style =
        content::SECURITY_STYLE_AUTHENTICATION_BROKEN;
    entry->GetSSL().content_status |= SSLStatus::RAN_INSECURE_CONTENT;
    return;
  }

  if (web_contents->DisplayedInsecureContent())
    entry->GetSSL().content_status |= SSLStatus::DISPLAYED_INSECURE_CONTENT;
}

void SSLPolicy::OnAllowCertificate(scoped_refptr<SSLCertErrorHandler> handler,
                                   bool allow) {
  if (allow) {
    // Default behavior for accepting a certificate.
    // Note that we should not call SetMaxSecurityStyle here, because the active
    // NavigationEntry has just been deleted (in HideInterstitialPage) and the
    // new NavigationEntry will not be set until DidNavigate.  This is ok,
    // because the new NavigationEntry will have its max security style set
    // within DidNavigate.
    //
    // While AllowCertForHost() executes synchronously on this thread,
    // ContinueRequest() gets posted to a different thread. Calling
    // AllowCertForHost() first ensures deterministic ordering.
    backend_->AllowCertForHost(handler->ssl_info().cert,
                               handler->request_url().host());
    handler->ContinueRequest();
  } else {
    // Default behavior for rejecting a certificate.
    //
    // While DenyCertForHost() executes synchronously on this thread,
    // CancelRequest() gets posted to a different thread. Calling
    // DenyCertForHost() first ensures deterministic ordering.
    backend_->DenyCertForHost(handler->ssl_info().cert,
                              handler->request_url().host());
    handler->CancelRequest();
  }
}

////////////////////////////////////////////////////////////////////////////////
// Certificate Error Routines

void SSLPolicy::OnCertErrorInternal(SSLCertErrorHandler* handler,
                                    bool overridable,
                                    bool strict_enforcement) {
  if (handler->resource_type() != ResourceType::MAIN_FRAME) {
    // A sub-resource has a certificate error.  The user doesn't really
    // have a context for making the right decision, so block the
    // request hard, without an info bar to allow showing the insecure
    // content.
    handler->DenyRequest();
    return;
  }

  bool cancel_request = false;
  content::GetContentClient()->browser()->AllowCertificateError(
      handler->render_process_id(),
      handler->render_view_id(),
      handler->cert_error(),
      handler->ssl_info(),
      handler->request_url(),
      overridable,
      strict_enforcement,
      base::Bind(&SSLPolicy::OnAllowCertificate, base::Unretained(this),
                 make_scoped_refptr(handler)),
      &cancel_request);
  if (cancel_request)
    handler->CancelRequest();
}

void SSLPolicy::InitializeEntryIfNeeded(NavigationEntryImpl* entry) {
  if (entry->GetSSL().security_style != content::SECURITY_STYLE_UNKNOWN)
    return;

  entry->GetSSL().security_style = entry->GetURL().SchemeIsSecure() ?
      content::SECURITY_STYLE_AUTHENTICATED :
      content::SECURITY_STYLE_UNAUTHENTICATED;
}

void SSLPolicy::OriginRanInsecureContent(const std::string& origin, int pid) {
  GURL parsed_origin(origin);
  if (parsed_origin.SchemeIsSecure())
    backend_->HostRanInsecureContent(parsed_origin.host(), pid);
}