Bug 1461590: Lower-case hostnames when adding substitutions. r=smaug f=dveditz

Since URI hostnames are defined to be case-insensitive, we only ever see
lower-case hostnames when looking up substitutions. That means that
substitutions containing capital letters are inaccessible, which is a footgun
that has hit many people.

The handler should lower-case substitutions when they're added so that
look-ups are always case-insensitive.

MozReview-Commit-ID: C936hS2cSyY

--HG--
extra : rebase_source : a70e8ceb822879e51c3a40232b7dffdfb9c0a185

netwerk/protocol/res/SubstitutingProtocolHandler.cpp

@@ -14,6 +14,7 @@
 #include "nsIFile.h"
 #include "nsNetCID.h"
 #include "nsNetUtil.h"
+#include "nsReadableUtils.h"
 #include "nsURLHelper.h"
 #include "nsEscape.h"
 
@@ -306,8 +307,11 @@ SubstitutingProtocolHandler::SetSubstitution(const nsACString& root, nsIURI *bas
 }
 
 nsresult
-SubstitutingProtocolHandler::SetSubstitutionWithFlags(const nsACString& root, nsIURI *baseURI, uint32_t flags)
+SubstitutingProtocolHandler::SetSubstitutionWithFlags(const nsACString& origRoot, nsIURI *baseURI, uint32_t flags)
 {
+  nsAutoCString root;
+  ToLowerCase(origRoot, root);
+
   if (!baseURI) {
     mSubstitutions.Remove(root);
     NotifyObservers(root, baseURI);
@@ -349,10 +353,13 @@ SubstitutingProtocolHandler::SetSubstitutionWithFlags(const nsACString& root, ns
 }
 
 nsresult
-SubstitutingProtocolHandler::GetSubstitution(const nsACString& root, nsIURI **result)
+SubstitutingProtocolHandler::GetSubstitution(const nsACString& origRoot, nsIURI **result)
 {
   NS_ENSURE_ARG_POINTER(result);
 
+  nsAutoCString root;
+  ToLowerCase(origRoot, root);
+
   SubstitutionEntry entry;
   if (mSubstitutions.Get(root, &entry)) {
     nsCOMPtr<nsIURI> baseURI = entry.baseURI;
@@ -367,6 +374,12 @@ SubstitutingProtocolHandler::GetSubstitution(const nsACString& root, nsIURI **re
 nsresult
 SubstitutingProtocolHandler::GetSubstitutionFlags(const nsACString& root, uint32_t* flags)
 {
+#ifdef DEBUG
+  nsAutoCString lcRoot;
+  ToLowerCase(root, lcRoot);
+  MOZ_ASSERT(root.Equals(lcRoot), "GetSubstitutionFlags should never receive mixed-case root name");
+#endif
+
   *flags = 0;
   SubstitutionEntry entry;
   if (mSubstitutions.Get(root, &entry)) {
@@ -379,9 +392,13 @@ SubstitutingProtocolHandler::GetSubstitutionFlags(const nsACString& root, uint32
 }
 
 nsresult
-SubstitutingProtocolHandler::HasSubstitution(const nsACString& root, bool *result)
+SubstitutingProtocolHandler::HasSubstitution(const nsACString& origRoot, bool *result)
 {
   NS_ENSURE_ARG_POINTER(result);
+
+  nsAutoCString root;
+  ToLowerCase(origRoot, root);
+
   *result = HasSubstitution(root);
   return NS_OK;
 }

netwerk/protocol/res/nsISubstitutingProtocolHandler.idl

@@ -25,8 +25,8 @@ interface nsISubstitutingProtocolHandler : nsIProtocolHandler
    *
    * A null baseURI removes the specified substitution.
    *
-   * A root key should always be lowercase; however, this may not be
-   * enforced.
+   * The root key will be converted to lower-case to conform to
+   * case-insensitive URI hostname matching behavior.
    */
   [must_use] void setSubstitution(in ACString root, in nsIURI baseURI);
 

netwerk/test/unit/test_substituting_protocol_handler.js

@@ -0,0 +1,41 @@
+"use strict";
+
+ChromeUtils.import("resource://gre/modules/Services.jsm");
+
+add_task(async function test_case_insensitive_substitutions() {
+  let resProto = Services.io.getProtocolHandler("resource")
+    .QueryInterface(Ci.nsISubstitutingProtocolHandler);
+
+  let uri = Services.io.newFileURI(do_get_file("data"));
+
+  resProto.setSubstitution("FooBar", uri);
+  resProto.setSubstitutionWithFlags("BarBaz", uri, 0);
+
+  equal(resProto.resolveURI(Services.io.newURI("resource://foobar/")),
+        uri.spec, "Got correct resolved URI for setSubstitution");
+
+  equal(resProto.resolveURI(Services.io.newURI("resource://foobar/")),
+        uri.spec, "Got correct resolved URI for setSubstitutionWithFlags");
+
+  ok(resProto.hasSubstitution("foobar"), "hasSubstitution works with all-lower-case root");
+  ok(resProto.hasSubstitution("FooBar"), "hasSubstitution works with mixed-case root");
+
+  equal(resProto.getSubstitution("foobar").spec, uri.spec,
+        "getSubstitution works with all-lower-case root");
+  equal(resProto.getSubstitution("FooBar").spec, uri.spec,
+        "getSubstitution works with mixed-case root");
+
+  resProto.setSubstitution("foobar", null);
+  resProto.setSubstitution("barbaz", null);
+
+  Assert.throws(() => resProto.resolveURI(Services.io.newURI("resource://foobar/")),
+                e => e.result == Cr.NS_ERROR_NOT_AVAILABLE,
+                "Correctly unregistered case-insensitive substitution in setSubstitution");
+  Assert.throws(() => resProto.resolveURI(Services.io.newURI("resource://barbaz/")),
+                e => e.result == Cr.NS_ERROR_NOT_AVAILABLE,
+                "Correctly unregistered case-insensitive substitution in setSubstitutionWithFlags");
+
+  Assert.throws(() => resProto.getSubstitution("foobar"),
+                e => e.result == Cr.NS_ERROR_NOT_AVAILABLE,
+                "foobar substitution has been removed");
+});

netwerk/test/unit/xpcshell.ini

@@ -421,3 +421,4 @@ run-sequentially = node server exceptions dont replay well
 # http2-using tests require node available
 skip-if = os == "android"
 [test_ioservice.js]
+[test_substituting_protocol_handler.js]