// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/security_state/core/security_state.h"

#include <stdint.h>
#include <string>

#include "base/command_line.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/field_trial_params.h"
#include "base/metrics/histogram_macros.h"
#include "build/build_config.h"
#include "net/ssl/ssl_cipher_suite_names.h"
#include "net/ssl/ssl_connection_status_flags.h"
#include "services/network/public/cpp/is_potentially_trustworthy.h"

namespace security_state {

namespace {

std::string GetHistogramSuffixForSecurityLevel(
    security_state::SecurityLevel level) {
  switch (level) {
    case SECURE:
      return "SECURE";
    case NONE:
      return "NONE";
    case WARNING:
      return "WARNING";
    case DANGEROUS:
      return "DANGEROUS";
    default:
      return "OTHER";
  }
}

std::string GetHistogramSuffixForSafetyTipStatus(
    security_state::SafetyTipStatus safety_tip_status) {
  switch (safety_tip_status) {
    case security_state::SafetyTipStatus::kUnknown:
      return "SafetyTip_Unknown";
    case security_state::SafetyTipStatus::kNone:
      return "SafetyTip_None";
    case security_state::SafetyTipStatus::kLookalike:
      return "SafetyTip_Lookalike";
    case security_state::SafetyTipStatus::kLookalikeIgnored:
      return "SafetyTip_LookalikeIgnored";
  }
  NOTREACHED();
}

}  // namespace

SecurityLevel GetSecurityLevel(
    const VisibleSecurityState& visible_security_state) {
  // Override the connection security information if the website failed the
  // browser's malware checks.
  if (visible_security_state.malicious_content_status !=
      MALICIOUS_CONTENT_STATUS_NONE) {
    return DANGEROUS;
  }

  // If the navigation was upgraded to HTTPS because of HTTPS-First Mode, but
  // did not succeed and is showing the HTTPS-First Mode interstitial, set the
  // security level to WARNING. The HTTPS-First Mode interstitial warning is
  // considered "less serious" than the general certificate error interstitials.
  //
  // This check must come before the checks for `connection_info_initialized`
  // (because the HTTPS-First Mode intersitital can trigger if the HTTPS version
  // of the page does not commit) and certificate errors (because the
  // HTTPS-First Mode interstitial takes precedent if the certificate error
  // occurred due to an upgraded main-frame navigation).
  if (visible_security_state.is_https_only_mode_upgraded &&
      visible_security_state.is_error_page) {
    return WARNING;
  }

  if (!visible_security_state.connection_info_initialized) {
    return NONE;
  }

  // Set the security level to DANGEROUS for major certificate errors.
  if (HasMajorCertificateError(visible_security_state)) {
    return DANGEROUS;
  }
  DCHECK(!net::IsCertStatusError(visible_security_state.cert_status));

  const GURL& url = visible_security_state.url;

  // data: URLs don't define a secure context, and are a vector for spoofing.
  // Display a "Not secure" badge for all these URLs.
  if (url.SchemeIs(url::kDataScheme)) {
    return WARNING;
  }

  // Display DevTools pages as neutral since we can't be confident the page
  // is secure, but also don't want the "Not secure" badge.
  if (visible_security_state.is_devtools) {
    return NONE;
  }

  // Downgrade the security level for active insecure subresources. This comes
  // before handling non-cryptographic schemes below, because secure pages with
  // non-cryptographic schemes (e.g., about:blank) can still have mixed content.
  if (visible_security_state.ran_mixed_content ||
      visible_security_state.ran_content_with_cert_errors) {
    return kRanInsecureContentLevel;
  }

  // Choose the appropriate security level for requests to HTTP and remaining
  // pseudo URLs (blob:, filesystem:). filesystem: is a standard scheme so does
  // not need to be explicitly listed here.
  // TODO(meacer): Remove special case for blob (crbug.com/684751).
  const bool is_cryptographic_with_certificate =
      visible_security_state.url.SchemeIsCryptographic() &&
      visible_security_state.certificate;
  if (!is_cryptographic_with_certificate) {
    if (!visible_security_state.is_error_page &&
        !network::IsUrlPotentiallyTrustworthy(url) &&
        (url.IsStandard() || url.SchemeIs(url::kBlobScheme))) {
#if !BUILDFLAG(IS_ANDROID)
      // On Desktop, Reader Mode pages have their own visible security state in
      // the omnibox. Display ReaderMode pages as neutral even if the original
      // URL was secure, because Chrome has modified the content so we don't
      // want to present it as the actual content that the server sent.
      // Distilled pages should not contain forms, payment handlers, or other JS
      // from the original URL, so they won't be affected by a downgraded
      // security level. On Desktop, Reader Mode is only run on SECURE pages and
      // and does not load mixed content or bad certificate subresources.
      if (visible_security_state.is_reader_mode) {
        return NONE;
      }
#endif  // !BUILDFLAG(IS_ANDROID)
      return WARNING;
    }
    return NONE;
  }

  // In most cases, SHA1 use is treated as a certificate error, in which case
  // DANGEROUS will have been returned above. If SHA1 was permitted by policy,
  // downgrade the security level to Neutral.
  if (IsSHA1InChain(visible_security_state)) {
    return NONE;
  }

  // Active mixed content is handled above.
  DCHECK(!visible_security_state.ran_mixed_content);
  DCHECK(!visible_security_state.ran_content_with_cert_errors);

  if (visible_security_state.displayed_mixed_content) {
    return kDisplayedInsecureContentWarningLevel;
  }

  if ((visible_security_state.contained_mixed_form &&
       !visible_security_state.should_treat_displayed_mixed_forms_as_secure) ||
      visible_security_state.displayed_content_with_cert_errors) {
    return kDisplayedInsecureContentLevel;
  }

  if (visible_security_state.is_view_source) {
    return NONE;
  }

  return SECURE;
}

bool HasMajorCertificateError(
    const VisibleSecurityState& visible_security_state) {
  if (!visible_security_state.connection_info_initialized)
    return false;

  const bool is_cryptographic_with_certificate =
      visible_security_state.url.SchemeIsCryptographic() &&
      visible_security_state.certificate;

  const bool is_major_cert_error =
      net::IsCertStatusError(visible_security_state.cert_status);

  return is_cryptographic_with_certificate && is_major_cert_error;
}

VisibleSecurityState::VisibleSecurityState()
    : malicious_content_status(MALICIOUS_CONTENT_STATUS_NONE),
      connection_info_initialized(false),
      cert_status(0),
      connection_status(0),
      key_exchange_group(0),
      peer_signature_algorithm(0),
      displayed_mixed_content(false),
      contained_mixed_form(false),
      ran_mixed_content(false),
      displayed_content_with_cert_errors(false),
      ran_content_with_cert_errors(false),
      pkp_bypassed(false),
      is_error_page(false),
      is_view_source(false),
      is_devtools(false),
      is_reader_mode(false),
      should_treat_displayed_mixed_forms_as_secure(false),
      is_https_only_mode_upgraded(false) {}

VisibleSecurityState::VisibleSecurityState(const VisibleSecurityState& other) =
    default;
VisibleSecurityState& VisibleSecurityState::operator=(
    const VisibleSecurityState& other) = default;

VisibleSecurityState::~VisibleSecurityState() = default;

bool IsSchemeCryptographic(const GURL& url) {
  return url.is_valid() && url.SchemeIsCryptographic();
}

bool IsOriginLocalhostOrFile(const GURL& url) {
  return url.is_valid() && (net::IsLocalhost(url) || url.SchemeIsFile());
}

bool IsSslCertificateValid(SecurityLevel security_level) {
  return security_level == SECURE;
}

std::string GetSecurityLevelHistogramName(
    const std::string& prefix,
    security_state::SecurityLevel level) {
  return prefix + "." + GetHistogramSuffixForSecurityLevel(level);
}

std::string GetSafetyTipHistogramName(const std::string& prefix,
                                      SafetyTipStatus safety_tip_status) {
  return prefix + "." + GetHistogramSuffixForSafetyTipStatus(safety_tip_status);
}

bool IsSHA1InChain(const VisibleSecurityState& visible_security_state) {
  return visible_security_state.certificate &&
         (visible_security_state.cert_status &
          net::CERT_STATUS_SHA1_SIGNATURE_PRESENT);
}

}  // namespace security_state