Move error classification into the ssl_errors component

chrome/browser/ssl/ssl_error_classification.cc

-// Copyright 2014 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 <vector>
-
-#include "chrome/browser/ssl/ssl_error_classification.h"
-
-#include "base/build_time.h"
-#include "base/lazy_instance.h"
-#include "base/metrics/histogram_macros.h"
-#include "base/strings/string_split.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/time/time.h"
-#include "components/ssl_errors/error_info.h"
-#include "components/url_formatter/url_formatter.h"
-#include "net/base/net_util.h"
-#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
-#include "net/cert/x509_cert_types.h"
-#include "net/cert/x509_certificate.h"
-#include "url/gurl.h"
-
-#if defined(OS_WIN)
-#include "base/win/win_util.h"
-#include "base/win/windows_version.h"
-#endif
-
-using base::Time;
-using base::TimeTicks;
-using base::TimeDelta;
-
-namespace {
-
-// Events for UMA. Do not reorder or change!
-enum SSLInterstitialCause {
-  CLOCK_PAST,
-  CLOCK_FUTURE,
-  WWW_SUBDOMAIN_MATCH,
-  SUBDOMAIN_MATCH,
-  SUBDOMAIN_INVERSE_MATCH,
-  SUBDOMAIN_OUTSIDE_WILDCARD,
-  HOST_NAME_NOT_KNOWN_TLD,
-  LIKELY_MULTI_TENANT_HOSTING,
-  LOCALHOST,
-  PRIVATE_URL,
-  AUTHORITY_ERROR_CAPTIVE_PORTAL,  // Deprecated in M47.
-  SELF_SIGNED,
-  EXPIRED_RECENTLY,
-  LIKELY_SAME_DOMAIN,
-  UNUSED_INTERSTITIAL_CAUSE_ENTRY,
-};
-
-void RecordSSLInterstitialCause(bool overridable, SSLInterstitialCause event) {
-  if (overridable) {
-    UMA_HISTOGRAM_ENUMERATION("interstitial.ssl.cause.overridable", event,
-                              UNUSED_INTERSTITIAL_CAUSE_ENTRY);
-  } else {
-    UMA_HISTOGRAM_ENUMERATION("interstitial.ssl.cause.nonoverridable", event,
-                              UNUSED_INTERSTITIAL_CAUSE_ENTRY);
-  }
-}
-
-int GetLevensteinDistance(const std::string& str1,
-                          const std::string& str2) {
-  if (str1 == str2)
-    return 0;
-  if (str1.size() == 0)
-    return str2.size();
-  if (str2.size() == 0)
-    return str1.size();
-  std::vector<int> kFirstRow(str2.size() + 1, 0);
-  std::vector<int> kSecondRow(str2.size() + 1, 0);
-
-  for (size_t i = 0; i < kFirstRow.size(); ++i)
-    kFirstRow[i] = i;
-  for (size_t i = 0; i < str1.size(); ++i) {
-    kSecondRow[0] = i + 1;
-    for (size_t j = 0; j < str2.size(); ++j) {
-      int cost = str1[i] == str2[j] ? 0 : 1;
-      kSecondRow[j+1] = std::min(std::min(
-          kSecondRow[j] + 1, kFirstRow[j + 1] + 1), kFirstRow[j] + cost);
-    }
-    for (size_t j = 0; j < kFirstRow.size(); j++)
-      kFirstRow[j] = kSecondRow[j];
-  }
-  return kSecondRow[str2.size()];
-}
-
-// The time to use when doing build time operations in browser tests.
-base::LazyInstance<base::Time> g_testing_build_time = LAZY_INSTANCE_INITIALIZER;
-
-} // namespace
-
-SSLErrorClassification::SSLErrorClassification(const base::Time& current_time,
-                                               const GURL& url,
-                                               int cert_error,
-                                               const net::X509Certificate& cert)
-    : current_time_(current_time),
-      request_url_(url),
-      cert_error_(cert_error),
-      cert_(cert) {}
-
-SSLErrorClassification::~SSLErrorClassification() { }
-
-void SSLErrorClassification::RecordUMAStatistics(
-    bool overridable) const {
-  ssl_errors::ErrorInfo::ErrorType type =
-      ssl_errors::ErrorInfo::NetErrorToErrorType(cert_error_);
-  UMA_HISTOGRAM_ENUMERATION("interstitial.ssl_error_type", type,
-                            ssl_errors::ErrorInfo::END_OF_ENUM);
-  switch (type) {
-    case ssl_errors::ErrorInfo::CERT_DATE_INVALID: {
-      if (IsUserClockInThePast(base::Time::NowFromSystemTime())) {
-        RecordSSLInterstitialCause(overridable, CLOCK_PAST);
-      } else if (IsUserClockInTheFuture(base::Time::NowFromSystemTime())) {
-        RecordSSLInterstitialCause(overridable, CLOCK_FUTURE);
-      } else if (cert_.HasExpired() &&
-                 (current_time_ - cert_.valid_expiry()).InDays() < 28) {
-        RecordSSLInterstitialCause(overridable, EXPIRED_RECENTLY);
-      }
-      break;
-    }
-    case ssl_errors::ErrorInfo::CERT_COMMON_NAME_INVALID: {
-      std::string host_name = request_url_.host();
-      if (IsHostNameKnownTLD(host_name)) {
-        Tokens host_name_tokens = Tokenize(host_name);
-        if (IsWWWSubDomainMatch())
-          RecordSSLInterstitialCause(overridable, WWW_SUBDOMAIN_MATCH);
-        if (IsSubDomainOutsideWildcard(host_name_tokens))
-          RecordSSLInterstitialCause(overridable, SUBDOMAIN_OUTSIDE_WILDCARD);
-        std::vector<std::string> dns_names;
-        cert_.GetDNSNames(&dns_names);
-        std::vector<Tokens> dns_name_tokens = GetTokenizedDNSNames(dns_names);
-        if (NameUnderAnyNames(host_name_tokens, dns_name_tokens))
-          RecordSSLInterstitialCause(overridable, SUBDOMAIN_MATCH);
-        if (AnyNamesUnderName(dns_name_tokens, host_name_tokens))
-          RecordSSLInterstitialCause(overridable, SUBDOMAIN_INVERSE_MATCH);
-        if (IsCertLikelyFromMultiTenantHosting())
-          RecordSSLInterstitialCause(overridable, LIKELY_MULTI_TENANT_HOSTING);
-        if (IsCertLikelyFromSameDomain())
-          RecordSSLInterstitialCause(overridable, LIKELY_SAME_DOMAIN);
-      } else {
-         RecordSSLInterstitialCause(overridable, HOST_NAME_NOT_KNOWN_TLD);
-      }
-      break;
-    }
-    case ssl_errors::ErrorInfo::CERT_AUTHORITY_INVALID: {
-      const std::string& hostname = request_url_.HostNoBrackets();
-      if (net::IsLocalhost(hostname))
-        RecordSSLInterstitialCause(overridable, LOCALHOST);
-      if (IsHostnameNonUniqueOrDotless(hostname))
-        RecordSSLInterstitialCause(overridable, PRIVATE_URL);
-      if (net::X509Certificate::IsSelfSigned(cert_.os_cert_handle()))
-        RecordSSLInterstitialCause(overridable, SELF_SIGNED);
-      break;
-    }
-    default:
-      break;
-  }
-  UMA_HISTOGRAM_ENUMERATION("interstitial.ssl.connection_type",
-                            net::NetworkChangeNotifier::GetConnectionType(),
-                            net::NetworkChangeNotifier::CONNECTION_LAST);
-}
-
-bool SSLErrorClassification::IsUserClockInThePast(const base::Time& time_now) {
-  base::Time build_time;
-  if (!g_testing_build_time.Get().is_null()) {
-    build_time = g_testing_build_time.Get();
-  } else {
-#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
-    return false;
-#else
-    build_time = base::GetBuildTime();
-#endif
-  }
-
-  if (time_now < build_time - base::TimeDelta::FromDays(2))
-    return true;
-  return false;
-}
-
-bool SSLErrorClassification::IsUserClockInTheFuture(
-    const base::Time& time_now) {
-  base::Time build_time;
-  if (!g_testing_build_time.Get().is_null()) {
-    build_time = g_testing_build_time.Get();
-  } else {
-#if defined(DONT_EMBED_BUILD_METADATA) && !defined(OFFICIAL_BUILD)
-    return false;
-#else
-    build_time = base::GetBuildTime();
-#endif
-  }
-
-  if (time_now > build_time + base::TimeDelta::FromDays(365))
-    return true;
-  return false;
-}
-
-// static
-void SSLErrorClassification::SetBuildTimeForTesting(
-    const base::Time& testing_time) {
-  g_testing_build_time.Get() = testing_time;
-}
-
-bool SSLErrorClassification::MaybeWindowsLacksSHA256Support() {
-#if defined(OS_WIN)
-  return !base::win::MaybeHasSHA256Support();
-#else
-  return false;
-#endif
-}
-
-bool SSLErrorClassification::IsHostNameKnownTLD(const std::string& host_name) {
-  size_t tld_length =
-      net::registry_controlled_domains::GetRegistryLength(
-          host_name,
-          net::registry_controlled_domains::EXCLUDE_UNKNOWN_REGISTRIES,
-          net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES);
-  if (tld_length == 0 || tld_length == std::string::npos)
-    return false;
-  return true;
-}
-
-std::vector<SSLErrorClassification::Tokens> SSLErrorClassification::
-GetTokenizedDNSNames(const std::vector<std::string>& dns_names) {
-  std::vector<std::vector<std::string>> dns_name_tokens;
-  for (size_t i = 0; i < dns_names.size(); ++i) {
-    std::vector<std::string> dns_name_token_single;
-    if (dns_names[i].empty() || dns_names[i].find('\0') != std::string::npos
-        || !(IsHostNameKnownTLD(dns_names[i]))) {
-      dns_name_token_single.push_back(std::string());
-    } else {
-      dns_name_token_single = Tokenize(dns_names[i]);
-    }
-    dns_name_tokens.push_back(dns_name_token_single);
-  }
-  return dns_name_tokens;
-}
-
-size_t SSLErrorClassification::FindSubDomainDifference(
-    const Tokens& potential_subdomain, const Tokens& parent) const {
-  // A check to ensure that the number of tokens in the tokenized_parent is
-  // less than the tokenized_potential_subdomain.
-  if (parent.size() >= potential_subdomain.size())
-    return 0;
-
-  size_t tokens_match = 0;
-  size_t diff_size = potential_subdomain.size() - parent.size();
-  for (size_t i = 0; i < parent.size(); ++i) {
-    if (parent[i] == potential_subdomain[i + diff_size])
-      tokens_match++;
-  }
-  if (tokens_match == parent.size())
-    return diff_size;
-  return 0;
-}
-
-SSLErrorClassification::Tokens SSLErrorClassification::
-Tokenize(const std::string& name) {
-  return base::SplitString(
-      name, ".", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
-}
-
-// We accept the inverse case for www for historical reasons.
-bool SSLErrorClassification::GetWWWSubDomainMatch(
-    const std::string& host_name,
-    const std::vector<std::string>& dns_names,
-    std::string* www_match_host_name) {
-  if (IsHostNameKnownTLD(host_name)) {
-    // Need to account for all possible domains given in the SSL certificate.
-    for (size_t i = 0; i < dns_names.size(); ++i) {
-      if (dns_names[i].empty() ||
-          dns_names[i].find('\0') != std::string::npos ||
-          dns_names[i].length() == host_name.length() ||
-          !IsHostNameKnownTLD(dns_names[i])) {
-        continue;
-      } else if (dns_names[i].length() > host_name.length()) {
-        if (url_formatter::StripWWW(base::ASCIIToUTF16(dns_names[i])) ==
-            base::ASCIIToUTF16(host_name)) {
-          *www_match_host_name = dns_names[i];
-          return true;
-        }
-      } else {
-        if (url_formatter::StripWWW(base::ASCIIToUTF16(host_name)) ==
-            base::ASCIIToUTF16(dns_names[i])) {
-          *www_match_host_name = dns_names[i];
-          return true;
-        }
-      }
-    }
-  }
-  return false;
-}
-
-bool SSLErrorClassification::IsWWWSubDomainMatch() const {
-  const std::string& host_name = request_url_.host();
-  std::vector<std::string> dns_names;
-  cert_.GetDNSNames(&dns_names);
-  std::string www_host;
-  return GetWWWSubDomainMatch(host_name, dns_names, &www_host);
-}
-
-bool SSLErrorClassification::NameUnderAnyNames(
-    const Tokens& child,
-    const std::vector<Tokens>& potential_parents) const {
-  bool result = false;
-  // Need to account for all the possible domains given in the SSL certificate.
-  for (size_t i = 0; i < potential_parents.size(); ++i) {
-    if (potential_parents[i].empty() ||
-        potential_parents[i].size() >= child.size()) {
-      result = result || false;
-    } else {
-      size_t domain_diff = FindSubDomainDifference(child,
-                                                   potential_parents[i]);
-      if (domain_diff == 1 &&  child[0] != "www")
-        result = result || true;
-    }
-  }
-  return result;
-}
-
-bool SSLErrorClassification::AnyNamesUnderName(
-    const std::vector<Tokens>& potential_children,
-    const Tokens& parent) const {
-  bool result = false;
-  // Need to account for all the possible domains given in the SSL certificate.
-  for (size_t i = 0; i < potential_children.size(); ++i) {
-    if (potential_children[i].empty() ||
-        potential_children[i].size() <= parent.size()) {
-      result = result || false;
-    } else {
-      size_t domain_diff = FindSubDomainDifference(potential_children[i],
-                                                   parent);
-      if (domain_diff == 1 &&  potential_children[i][0] != "www")
-        result = result || true;
-    }
-  }
-  return result;
-}
-
-bool SSLErrorClassification::IsSubDomainOutsideWildcard(
-    const Tokens& host_name_tokens) const {
-  std::string host_name = request_url_.host();
-  std::vector<std::string> dns_names;
-  cert_.GetDNSNames(&dns_names);
-  bool result = false;
-
-  // This method requires that the host name be longer than the dns name on
-  // the certificate.
-  for (size_t i = 0; i < dns_names.size(); ++i) {
-    const std::string& name = dns_names[i];
-    if (name.length() < 2 || name.length() >= host_name.length() ||
-        name.find('\0') != std::string::npos ||
-        !IsHostNameKnownTLD(name)
-        || name[0] != '*' || name[1] != '.') {
-      continue;
-    }
-
-    // Move past the "*.".
-    std::string extracted_dns_name = name.substr(2);
-    if (FindSubDomainDifference(
-        host_name_tokens, Tokenize(extracted_dns_name)) == 2) {
-      return true;
-    }
-  }
-  return result;
-}
-
-bool SSLErrorClassification::IsCertLikelyFromMultiTenantHosting() const {
-  std::string host_name = request_url_.host();
-  std::vector<std::string> dns_names;
-  std::vector<std::string> dns_names_domain;
-  cert_.GetDNSNames(&dns_names);
-  size_t dns_names_size = dns_names.size();
-
-  // If there is only 1 DNS name then it is definitely not a shared certificate.
-  if (dns_names_size == 0 || dns_names_size == 1)
-    return false;
-
-  // Check to see if all the domains in the SAN field in the SSL certificate are
-  // the same or not.
-  for (size_t i = 0; i < dns_names_size; ++i) {
-    dns_names_domain.push_back(
-        net::registry_controlled_domains::
-        GetDomainAndRegistry(
-            dns_names[i],
-            net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES));
-  }
-  for (size_t i = 1; i < dns_names_domain.size(); ++i) {
-    if (dns_names_domain[i] != dns_names_domain[0])
-      return false;
-  }
-
-  // If the number of DNS names is more than 5 then assume that it is a shared
-  // certificate.
-  static const int kDistinctNameThreshold = 5;
-  if (dns_names_size > kDistinctNameThreshold)
-    return true;
-
-  // Heuristic - The edit distance between all the strings should be at least 5
-  // for it to be counted as a shared SSLCertificate. If even one pair of
-  // strings edit distance is below 5 then the certificate is no longer
-  // considered as a shared certificate. Include the host name in the URL also
-  // while comparing.
-  dns_names.push_back(host_name);
-  static const int kMinimumEditDsitance = 5;
-  for (size_t i = 0; i < dns_names_size; ++i) {
-    for (size_t j = i + 1; j < dns_names_size; ++j) {
-      int edit_distance = GetLevensteinDistance(dns_names[i], dns_names[j]);
-      if (edit_distance < kMinimumEditDsitance)
-        return false;
-    }
-  }
-  return true;
-}
-
-bool SSLErrorClassification::IsCertLikelyFromSameDomain() const {
-  std::string host_name = request_url_.host();
-  std::vector<std::string> dns_names;
-  cert_.GetDNSNames(&dns_names);
-
-  dns_names.push_back(host_name);
-  std::vector<std::string> dns_names_domain;
-
-  for (const std::string& dns_name : dns_names) {
-    dns_names_domain.push_back(
-        net::registry_controlled_domains::GetDomainAndRegistry(
-            dns_name,
-            net::registry_controlled_domains::INCLUDE_PRIVATE_REGISTRIES));
-  }
-
-  DCHECK(!dns_names_domain.empty());
-  const std::string& host_name_domain = dns_names_domain.back();
-
-  // Last element is the original domain. So, excluding it.
-  return std::find(dns_names_domain.begin(), dns_names_domain.end() - 1,
-                   host_name_domain) != dns_names_domain.end() - 1;
-}
-
-// static
-bool SSLErrorClassification::IsHostnameNonUniqueOrDotless(
-    const std::string& hostname) {
-  return net::IsHostnameNonUnique(hostname) ||
-         hostname.find('.') == std::string::npos;
-}