Bug 1948543 - Do not use file extension when sniffing mime type r=necko-reviewers,willdurand,kershaw,devtools-reviewers,bomsy,geckoview-reviewers,nalexander

This patch adds a network.sniff.use_extension pref.
When false, the file extension of a URL will only be used to sniff file://

Differential Revision: https://phabricator.services.mozilla.com/D246585

Author: valenting

browser/components/extensions/test/browser/browser_ext_search_favicon.js

@@ -26,7 +26,8 @@ SearchTestUtils.init(this);
 const FAKE_ICON_DATA = "RmFrZSBpY29uIGRhdGE=";
 
 // Base64-encoded "HTTP icon data".
-const HTTP_ICON_DATA = "SFRUUCBpY29uIGRhdGE=";
+const HTTP_ICON_DATA =
+  "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC";
 const HTTP_ICON_URL = "http://example.org/ico.png";
 
 const IMAGE_DATA_URI =
@@ -37,6 +38,7 @@ add_setup(async () => {
     hosts: ["example.org"],
   });
   server.registerPathHandler("/ico.png", (request, response) => {
+    response.setHeader("Content-Type", "image/png");
     response.write(atob(HTTP_ICON_DATA));
   });
 

devtools/client/debugger/test/mochitest/browser_dbg-pretty-print-line-breaks.js

@@ -9,10 +9,10 @@
 requestLongerTimeout(2);
 
 const httpServer = createTestHTTPServer();
-httpServer.registerContentType("html", "text/html");
 
 httpServer.registerPathHandler("/doc_line_breaks.html", (request, response) => {
   response.setStatusLine(request.httpVersion, 200, "OK");
+  response.setHeader("Content-Type", "text/html");
   response.write(
     `TEST with line breaks\r\n<script>(function(){\r\n})('test')</script>`
   );

mobile/android/geckoview/src/androidTest/java/org/mozilla/geckoview/test/util/TestServer.kt

@@ -3,7 +3,6 @@ package org.mozilla.geckoview.test.util
 import android.content.Context
 import android.content.res.AssetManager
 import android.os.SystemClock
-import android.webkit.MimeTypeMap
 import com.koushikdutta.async.ByteBufferList
 import com.koushikdutta.async.http.server.AsyncHttpServer
 import com.koushikdutta.async.http.server.AsyncHttpServerRequest
@@ -14,6 +13,7 @@ import org.json.JSONObject
 import java.io.FileNotFoundException
 import java.math.BigInteger
 import java.security.MessageDigest
+import java.util.Locale
 import java.util.Random
 import java.util.Vector
 
@@ -54,10 +54,31 @@ class TestServer @JvmOverloads constructor(
 
         val assetsCallback = HttpServerRequestCallback { request, response ->
             try {
-                val mimeType = MimeTypeMap.getSingleton()
-                    .getMimeTypeFromExtension(MimeTypeMap.getFileExtensionFromUrl(request.path))
-                val name = request.path.substring("/assets/".count())
-                val asset = assets.open(name).readBytes()
+                val fileName = request.path.substring("/assets/".length)
+                val asset = assets.open(fileName).readBytes()
+
+                val extension = fileName.substringAfterLast('.', "")
+                val mimeType = when (extension.lowercase(Locale.ROOT)) {
+                    "html", "htm" -> "text/html"
+                    "js" -> "application/javascript"
+                    "css" -> "text/css"
+                    "json" -> "application/json"
+                    "webmanifest" -> "application/manifest+json"
+                    "png" -> "image/png"
+                    "jpg", "jpeg" -> "image/jpeg"
+                    "gif" -> "image/gif"
+                    "webp" -> "image/webp"
+                    "svg" -> "image/svg+xml"
+                    "ico" -> "image/x-icon"
+                    "mp4" -> "video/mp4"
+                    "webm" -> "video/webm"
+                    "mp3" -> "audio/mpeg"
+                    "pdf" -> "application/pdf"
+                    "sjs" -> "application/javascript"
+                    else -> "application/octet-stream"
+                }
+
+                response.headers.set("Content-Type", mimeType)
 
                 customHeaders?.forEach { (header, value) ->
                     response.headers.set(header, value)

modules/libpref/init/StaticPrefList.yaml

@@ -13373,6 +13373,14 @@
   value: false
   mirror: always
 
+# If set to true, Firefox will use the file extension of a URL
+# to sniff its content type. When false, nsUnknownDecoder will
+# use the file extension only for file URLs
+- name: network.sniff.use_extension
+  type: RelaxedAtomicBool
+  value: false
+  mirror: always
+
 # Enables the predictive service.
 - name: network.predictor.enabled
   type: bool

netwerk/streamconv/converters/nsUnknownDecoder.cpp

@@ -24,6 +24,7 @@
 #include "nsQueryObject.h"
 #include "nsComponentManagerUtils.h"
 #include "nsServiceManagerUtils.h"
+#include "mozilla/StaticPrefs_network.h"
 
 #include <algorithm>
 
@@ -480,9 +481,14 @@ void nsUnknownDecoder::DetermineContentType(nsIRequest* aRequest) {
     return;
   }
 
+  nsCOMPtr<nsIURI> uri;
+  NS_GetFinalChannelURI(channel, getter_AddRefs(uri));
+
   // We don't know what this is yet.  Before we just give up, try
   // the URI from the request.
-  if (SniffURI(aRequest)) {
+  if ((StaticPrefs::network_sniff_use_extension() ||
+       (uri && uri->SchemeIs("file"))) &&
+      SniffURI(aRequest)) {
 #ifdef DEBUG
     MutexAutoLock lock(mMutex);
     NS_ASSERTION(!mContentType.IsEmpty(),
@@ -558,7 +564,7 @@ bool nsUnknownDecoder::SniffForHTML(nsIRequest* aRequest) {
 
 bool nsUnknownDecoder::SniffForXML(nsIRequest* aRequest) {
   // First see whether we can glean anything from the uri...
-  if (!SniffURI(aRequest)) {
+  if (!StaticPrefs::network_sniff_use_extension() || !SniffURI(aRequest)) {
     // Oh well; just generic XML will have to do
     MutexAutoLock lock(mMutex);
     mContentType = TEXT_XML;