[Lookalikes] Ignore signed exchange cache URLs if they are lookalikes

This CL detects and allows signed exchange cache URLs even if they are
lookalikes.

Signed Exchange cache URLs (the initial URL that redirects to the
SXG) serve application/signed-exchange Content-Type response header.
In this case, the navigation will always either fail or redirect to
the primary URL (getting the content either from inside the SXG or the
network depending on whether the validations succeed).

Bug: 1110151
Change-Id: I5a15c0248402e563bb34b9643c483d80770bd121
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441276
Commit-Queue: Mustafa Emre Acer <meacer@chromium.org>
Reviewed-by: Joe DeBlasio <jdeblasio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818052}

chrome/browser/lookalikes/lookalike_url_blocking_page.cc

@@ -30,6 +30,7 @@ LookalikeUrlBlockingPage::LookalikeUrlBlockingPage(
     const GURL& request_url,
     ukm::SourceId source_id,
     LookalikeUrlMatchType match_type,
+    bool is_signed_exchange,
     std::unique_ptr<
         security_interstitials::SecurityInterstitialControllerClient>
         controller_client)
@@ -39,7 +40,8 @@ LookalikeUrlBlockingPage::LookalikeUrlBlockingPage(
           std::move(controller_client)),
       safe_url_(safe_url),
       source_id_(source_id),
-      match_type_(match_type) {
+      match_type_(match_type),
+      is_signed_exchange_(is_signed_exchange) {
   controller()->metrics_helper()->RecordUserDecision(MetricsHelper::SHOW);
   controller()->metrics_helper()->RecordUserInteraction(
       MetricsHelper::TOTAL_VISITS);

chrome/browser/lookalikes/lookalike_url_blocking_page.h

@@ -32,6 +32,7 @@ class LookalikeUrlBlockingPage
       const GURL& request_url,
       ukm::SourceId source_id,
       LookalikeUrlMatchType match_type,
+      bool is_signed_exchange,
       std::unique_ptr<
           security_interstitials::SecurityInterstitialControllerClient>
           controller);
@@ -42,6 +43,8 @@ class LookalikeUrlBlockingPage
   security_interstitials::SecurityInterstitialPage::TypeID GetTypeForTesting()
       override;
 
+  bool is_signed_exchange_for_testing() const { return is_signed_exchange_; }
+
  protected:
   // SecurityInterstitialPage implementation:
   void CommandReceived(const std::string& command) override;
@@ -59,6 +62,9 @@ class LookalikeUrlBlockingPage
   const GURL safe_url_;
   ukm::SourceId source_id_;
   LookalikeUrlMatchType match_type_;
+  // True if the throttle encountered a response with
+  // is_signed_exchange_inner_response flag. Only checked in tests.
+  const bool is_signed_exchange_;
 
   DISALLOW_COPY_AND_ASSIGN(LookalikeUrlBlockingPage);
 };

chrome/browser/lookalikes/lookalike_url_navigation_throttle.cc

@@ -143,8 +143,9 @@ ThrottleCheckResult LookalikeUrlNavigationThrottle::ShowInterstitial(
       web_contents, url, safe_url);
 
   std::unique_ptr<LookalikeUrlBlockingPage> blocking_page(
-      new LookalikeUrlBlockingPage(web_contents, safe_url, url, source_id,
-                                   match_type, std::move(controller)));
+      new LookalikeUrlBlockingPage(
+          web_contents, safe_url, url, source_id, match_type,
+          handle->IsSignedExchangeInnerResponse(), std::move(controller)));
 
   base::Optional<std::string> error_page_contents =
       blocking_page->GetHTMLContents();
@@ -225,6 +226,28 @@ ThrottleCheckResult LookalikeUrlNavigationThrottle::PerformChecks(
     first_is_lookalike = false;
   }
 
+  // Allow signed exchange cache URLs such as
+  // https://example-com.site.test/package.sxg.
+  // Navigation throttles see signed exchanges as a redirect chain where
+  // Url 0: Cache URL (i.e. outer URL)
+  // Url 1: URL of the sgx package
+  // Url 2: Inner URL (the URL whose contents the sgx package contains)
+  //
+  // We want to allow lookalike cache URLs but not lookalike inner URLs, so we
+  // make an exception for this condition.
+  // TODO(meacer): Confirm that the assumption about cache URL being the 1st
+  // and inner URL being the last URL in the redirect chain is correct.
+  //
+  // Note that the signed exchange logic can still redirect the initial
+  // navigation to the fallback URL even if SGX checks fail (invalid cert,
+  // missing headers etc, see crbug.com/874323 for an example). Such navigations
+  // are not considered SGX navigations and IsSignedExchangeInnerResponse()
+  // will return false. We treat such navigations as simple redirects.
+  if (first_is_lookalike &&
+      navigation_handle()->IsSignedExchangeInnerResponse()) {
+    first_is_lookalike = false;
+  }
+
   if (!first_is_lookalike && !last_is_lookalike) {
     return content::NavigationThrottle::PROCEED;
   }

chrome/browser/ui/webui/interstitials/interstitial_ui.cc

@@ -273,7 +273,7 @@ std::unique_ptr<LookalikeUrlBlockingPage> CreateLookalikeInterstitialPage(
   }
   return std::make_unique<LookalikeUrlBlockingPage>(
       web_contents, safe_url, request_url, ukm::kInvalidSourceId,
-      LookalikeUrlMatchType::kNone,
+      LookalikeUrlMatchType::kNone, false,
       std::make_unique<LookalikeUrlControllerClient>(web_contents, request_url,
                                                      safe_url));
 }

content/test/data/sxg/generate-test-certs.sh

@@ -24,6 +24,11 @@ openssl ecparam -out prime256v1.key -name prime256v1 -genkey
 openssl req -new -sha256 -key prime256v1.key -out prime256v1-sha256.csr \
   -subj '/CN=test.example.org/O=Test/C=US'
 
+openssl req -new -sha256 -key prime256v1.key -out \
+  prime256v1-sha256-google-com.csr \
+  -subj '/CN=google-com.example.org/O=Test/C=US'
+
+
 # Generate a certificate whose validity period starts at 2019-06-01 and
 # valid for 90 days.
 openssl ca -batch \
@@ -34,6 +39,17 @@ openssl ca -batch \
   -in  prime256v1-sha256.csr \
   -out prime256v1-sha256.public.pem
 
+# Generate a certificate whose validity period starts at 2019-06-01 and
+# valid for 90 days. Same as above, but for google-com.example.org.
+openssl ca -batch \
+  -config google-com-ca.cnf \
+  -extensions sxg_cert \
+  -startdate 190601000000Z \
+  -enddate   190830000000Z \
+  -in  prime256v1-sha256-google-com.csr \
+  -out prime256v1-sha256-google-com.public.pem
+
+
 # Generate a certificate without CanSignHttpExchangesDraft extension.
 openssl ca -batch \
   -config ca.cnf \

content/test/data/sxg/generate-test-sxgs.sh

@@ -33,6 +33,11 @@ echo -n OCSP >$tmpdir/ocsp; echo -n SCT >$sctdir/dummy.sct
 gen-certurl -pem prime256v1-sha256.public.pem \
   -ocsp $tmpdir/ocsp -sctDir $sctdir > test.example.org.public.pem.cbor
 
+
+# Same as above, but for google-com.example.org.
+gen-certurl -pem prime256v1-sha256-google-com.public.pem \
+  -ocsp $tmpdir/ocsp -sctDir $sctdir > google-com.example.org.public.pem.cbor
+
 # Generate the certificate chain of "*.example.org", whose validity period is
 # more than 90 days.
 gen-certurl -pem prime256v1-sha256-validity-too-long.public.pem \
@@ -72,8 +77,8 @@ gen-signedexchange \
   -uri https://google-com.example.org/test/ \
   -status 200 \
   -content test.html \
-  -certificate prime256v1-sha256.public.pem \
-  -certUrl https://cert.example.org/cert.msg \
+  -certificate prime256v1-sha256-google-com.public.pem \
+  -certUrl https://google-com.example.org/cert.msg \
   -validityUrl https://google-com.example.org/resource.validity.msg \
   -privateKey prime256v1.key \
   -date $signature_date \

content/test/data/sxg/google-com-ca.cnf

+# This file is same as ca.cnf with the exception of subjectAltName field.
+[ca]
+default_ca = CA_root
+preserve   = yes
+
+[CA_root]
+dir            = out
+new_certs_dir  = $dir
+database       = $dir/index.txt
+serial         = $dir/serial
+certificate    = ../../../../net/data/ssl/certificates/root_ca_cert.pem
+private_key    = ../../../../net/data/ssl/certificates/root_ca_cert.pem
+default_md     = sha256
+unique_subject = no
+policy         = policy_anything
+
+[sxg_cert]
+basicConstraints = CA:FALSE
+# OID required for sxg since d54c469
+1.3.6.1.4.1.11129.2.1.22 = ASN1:NULL
+keyUsage = nonRepudiation, digitalSignature, keyEncipherment
+extendedKeyUsage = serverAuth
+subjectKeyIdentifier = hash
+authorityKeyIdentifier = keyid,issuer
+subjectAltName=DNS:google-com.example.org
+
+[policy_anything]
+# Default signing policy
+countryName            = optional
+stateOrProvinceName    = optional
+localityName           = optional
+organizationName       = optional
+organizationalUnitName = optional
+commonName             = optional
+emailAddress           = optional

content/test/data/sxg/google-com.example.org.public.pem.cbor.mock-http-headers

+HTTP/1.1 200 OK
+Content-Type: application/cert-chain+cbor

content/test/data/sxg/prime256v1-sha256-google-com.csr

+-----BEGIN CERTIFICATE REQUEST-----
+MIH4MIGfAgEAMD0xHzAdBgNVBAMMFmdvb2dsZS1jb20uZXhhbXBsZS5vcmcxDTAL
+BgNVBAoMBFRlc3QxCzAJBgNVBAYTAlVTMFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcD
+QgAElFfdVfWVnYyDSfXmIkjMokHtKd1SLpMcJiV1gzYsTABuyq5PUhaghqpelLbG
+vTBUEYH8BupWh2DdIF01fR3Kw6AAMAoGCCqGSM49BAMCA0gAMEUCIQC4wI2Lo4CN
+/8MDiD14faGKqizZZURk1wNln5qQ7ZhLngIgZ3XkkcNcemHTc5srzamFFNKJU2L3
+zpJjorgaC+H3rn8=
+-----END CERTIFICATE REQUEST-----

content/test/data/sxg/prime256v1-sha256-google-com.public.pem

+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number: 2 (0x2)
+        Signature Algorithm: sha256WithRSAEncryption
+        Issuer: C=US, ST=California, L=Mountain View, O=Test CA, CN=Test Root CA
+        Validity
+            Not Before: Jun  1 00:00:00 2019 GMT
+            Not After : Aug 30 00:00:00 2019 GMT
+        Subject: CN=google-com.example.org, O=Test, C=US
+        Subject Public Key Info:
+            Public Key Algorithm: id-ecPublicKey
+                Public-Key: (256 bit)
+                pub:
+                    04:94:57:dd:55:f5:95:9d:8c:83:49:f5:e6:22:48:
+                    cc:a2:41:ed:29:dd:52:2e:93:1c:26:25:75:83:36:
+                    2c:4c:00:6e:ca:ae:4f:52:16:a0:86:aa:5e:94:b6:
+                    c6:bd:30:54:11:81:fc:06:ea:56:87:60:dd:20:5d:
+                    35:7d:1d:ca:c3
+                ASN1 OID: prime256v1
+                NIST CURVE: P-256
+        X509v3 extensions:
+            X509v3 Basic Constraints: 
+                CA:FALSE
+            1.3.6.1.4.1.11129.2.1.22: 
+                ..
+            X509v3 Key Usage: 
+                Digital Signature, Non Repudiation, Key Encipherment
+            X509v3 Extended Key Usage: 
+                TLS Web Server Authentication
+            X509v3 Subject Key Identifier: 
+                CF:65:B9:9B:EE:0E:EC:8E:A6:B9:69:96:82:20:F4:F7:8B:8A:B2:FA
+            X509v3 Authority Key Identifier: 
+                keyid:9B:26:0B:8A:98:A9:BB:1D:B9:1F:1C:E3:1A:40:33:ED:8E:17:88:AB
+
+            X509v3 Subject Alternative Name: 
+                DNS:google-com.example.org
+    Signature Algorithm: sha256WithRSAEncryption
+         ae:16:c3:1d:a9:b1:53:86:22:ee:90:e6:07:e6:03:c1:a1:10:
+         79:98:32:d9:61:31:f2:27:5c:6a:a2:80:c6:0b:d1:40:16:06:
+         65:5e:b9:72:e1:77:e1:a9:02:bf:b9:18:56:8a:24:0f:b7:84:
+         94:d7:53:51:e6:9f:51:fd:7e:fe:d2:64:9e:73:d0:97:2d:2f:
+         ad:64:41:28:ef:9e:e7:86:ca:18:04:39:7d:7d:b1:9f:3c:20:
+         f4:44:5b:a0:d4:00:28:bf:8c:c2:50:c9:c8:5e:cf:d5:1c:37:
+         98:8e:2e:d8:81:71:43:79:77:60:6b:85:01:34:14:70:73:33:
+         1d:df:6e:2e:30:b5:99:ff:0c:ac:82:b5:23:c2:f4:8c:8a:e0:
+         53:f2:f4:3f:cb:18:78:3c:b3:f4:f9:41:e3:d4:83:75:24:c8:
+         b6:16:15:d7:36:d1:06:a3:9a:0b:59:6b:cd:e4:05:8e:25:d8:
+         1f:44:bf:30:20:3b:92:dd:66:74:3b:e6:d2:91:0c:5a:81:ac:
+         d1:9d:3f:9e:fe:cd:31:a0:36:40:58:6f:01:01:f5:9c:f7:ab:
+         81:91:3f:d3:f1:3c:29:a3:47:a0:60:71:55:86:8c:15:3e:9e:
+         0c:54:45:04:4c:10:33:36:09:c5:88:56:3a:8e:78:3b:dc:5d:
+         43:5a:cd:84
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----