Fix dictionary domain check problem.

Previous to this change, suffixing a "." to the URL from which a
dictionary was being suggested would allow servers to bypass the
check against a subdomain (e.g. evil.protected.good.com) setting a
dictionary to be used by a superdomain (.good.com).

BUG=389451
R=rsleevi@chromium.org

Review URL: https://codereview.chromium.org/574283006

Cr-Commit-Position: refs/heads/master@{#296246}

net/base/sdch_manager.cc

@@ -13,6 +13,27 @@
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "net/url_request/url_request_http_job.h"
 
+namespace {
+
+void StripTrailingDot(GURL* gurl) {
+  std::string host(gurl->host());
+
+  if (host.empty())
+    return;
+
+  if (*host.rbegin() != '.')
+    return;
+
+  host.resize(host.size() - 1);
+
+  GURL::Replacements replacements;
+  replacements.SetHostStr(host);
+  *gurl = gurl->ReplaceComponents(replacements);
+  return;
+}
+
+}  // namespace
+
 namespace net {
 
 //------------------------------------------------------------------------------
@@ -550,10 +571,14 @@ void SdchManager::AddSdchDictionary(const std::string& dictionary_text,
     line_start = line_end + 1;
   }
 
-  if (!IsInSupportedDomain(dictionary_url))
+  // Narrow fix for http://crbug.com/389451.
+  GURL dictionary_url_normalized(dictionary_url);
+  StripTrailingDot(&dictionary_url_normalized);
+
+  if (!IsInSupportedDomain(dictionary_url_normalized))
     return;
 
-  if (!Dictionary::CanSet(domain, path, ports, dictionary_url))
+  if (!Dictionary::CanSet(domain, path, ports, dictionary_url_normalized))
     return;
 
   // TODO(jar): Remove these hacks to preclude a DOS attack involving piles of
@@ -574,7 +599,8 @@ void SdchManager::AddSdchDictionary(const std::string& dictionary_text,
            << " and server hash " << server_hash;
   Dictionary* dictionary =
       new Dictionary(dictionary_text, header_end + 2, client_hash,
-                     dictionary_url, domain, path, expiration, ports);
+                     dictionary_url_normalized, domain,
+                     path, expiration, ports);
   dictionaries_[server_hash] = dictionary;
   return;
 }

net/base/sdch_manager_unittest.cc

@@ -278,6 +278,15 @@ TEST_F(SdchManagerTest, FailToSetDotHostPrefixDomainDictionary) {
                                  GURL("http://w.x.y.z.google.com")));
 }
 
+TEST_F(SdchManagerTest, FailToSetDotHostPrefixDomainDictionaryTrailingDot) {
+  std::string dictionary_domain("x.y.z.google.com");
+  std::string dictionary_text(NewSdchDictionary(dictionary_domain));
+
+  // Fail the HD with D being the domain and H having a dot requirement.
+  EXPECT_FALSE(AddSdchDictionary(dictionary_text,
+                                 GURL("http://w.x.y.z.google.com.")));
+}
+
 TEST_F(SdchManagerTest, FailToSetRepeatPrefixWithDotDictionary) {
   // Make sure that a prefix that matches the domain postfix won't confuse
   // the validation checks.
@@ -300,6 +309,42 @@ TEST_F(SdchManagerTest, CanSetLeadingDotDomainDictionary) {
   EXPECT_TRUE(AddSdchDictionary(dictionary_text, GURL("http://www.google.com")));
 }
 
+TEST_F(SdchManagerTest,
+       CanSetLeadingDotDomainDictionaryFromURLWithTrailingDot) {
+  // Make sure that a prefix that matches the domain postfix won't confuse
+  // the validation checks.
+  std::string dictionary_domain(".google.com");
+  std::string dictionary_text(NewSdchDictionary(dictionary_domain));
+
+  // Verify that a leading dot in the domain is acceptable, as long as the host
+  // name does not contain any dots preceding the matched domain name.
+  EXPECT_TRUE(AddSdchDictionary(dictionary_text,
+                                GURL("http://www.google.com.")));
+}
+
+TEST_F(SdchManagerTest, CannotSetLeadingDotDomainDictionary) {
+  // Make sure that a prefix that matches the domain postfix won't confuse
+  // the validation checks.
+  std::string dictionary_domain(".google.com");
+  std::string dictionary_text(NewSdchDictionary(dictionary_domain));
+
+  // Verify that a leading dot in the domain does not affect the name containing
+  // dots failure.
+  EXPECT_FALSE(AddSdchDictionary(dictionary_text,
+                                 GURL("http://www.subdomain.google.com")));
+}
+
+TEST_F(SdchManagerTest, CannotSetLeadingDotDomainDictionaryTrailingDot) {
+  // Make sure that a prefix that matches the domain postfix won't confuse
+  // the validation checks.
+  std::string dictionary_domain(".google.com");
+  std::string dictionary_text(NewSdchDictionary(dictionary_domain));
+
+  // Verify that a trailing period in the URL doesn't affect the check.
+  EXPECT_FALSE(AddSdchDictionary(dictionary_text,
+                                 GURL("http://www.subdomain.google.com.")));
+}
+
 // Make sure the order of the tests is not helping us or confusing things.
 // See test CanSetExactMatchDictionary above for first try.
 TEST_F(SdchManagerTest, CanStillSetExactMatchDictionary) {
@@ -509,4 +554,3 @@ TEST_F(SdchManagerTest, ClearDictionaryData) {
 }
 
 }  // namespace net
-