tor-browser

commit 4740e9deb9293fafafbbe59076ad9e61ccbdef47
parent 7e3bc66813a09440a6f77b8e4c27b7f31e8d87ab
Author: Randell Jesup <rjesup@mozilla.com>
Date:   Tue,  7 Oct 2025 17:56:03 +0000

Bug 1917970: only remove dcb and dcz Content-Encodings r=necko-reviewers,kershaw

Differential Revision: https://phabricator.services.mozilla.com/D264525

Diffstat:
M
netwerk/protocol/http/HttpBaseChannel.cpp
 | 
22
+++++++++++++++++-----

1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/netwerk/protocol/http/HttpBaseChannel.cpp b/netwerk/protocol/http/HttpBaseChannel.cpp
@@ -1521,6 +1521,7 @@ HttpBaseChannel::DoApplyContentConversions(nsIStreamListener* aNextListener,
   nsAutoCString newEncoding;
   char* cePtr = contentEncoding.BeginWriting();
   uint32_t count = 0;
+  bool removed_encoding = false;
   while (char* val = nsCRT::strtok(cePtr, HTTP_LWS ",", &cePtr)) {
     if (++count > 16) {
       // For compatibility with old code, we will just carry on without
@@ -1560,6 +1561,9 @@ HttpBaseChannel::DoApplyContentConversions(nsIStreamListener* aNextListener,
         }
         glean::http::content_encoding.AccumulateSingleSample(mode);
       }
+      if (from.EqualsLiteral("dcb") || from.EqualsLiteral("dcz")) {
+        removed_encoding = true;
+      }
       nextListener = converter;
     } else {
       if (val) LOG(("Unknown content encoding '%s', ignoring\n", val));
@@ -1570,11 +1574,19 @@ HttpBaseChannel::DoApplyContentConversions(nsIStreamListener* aNextListener,
     }
   }
 
-  LOG(("Changing Content-Encoding from %s to %s", contentEncoding.get(),
-       newEncoding.get()));
-  // Can't use SetHeader; we need to overwrite the current value
-  rv = mResponseHead->SetHeaderOverride(nsHttp::Content_Encoding, newEncoding);
-
+  // dcb and dcz encodings are removed when it's decompressed (always in
+  // the parent process).  However, in theory you could have
+  // Content-Encoding: dcb,gzip
+  // in which case we should pass it down to the content process as
+  // Content-Encoding: gzip
+  // This of course would be silly, but supported by the spec
+  if (removed_encoding) {
+    LOG(("Changing Content-Encoding from %s to %s", contentEncoding.get(),
+         newEncoding.get()));
+    // Can't use SetHeader; we need to overwrite the current value
+    rv =
+        mResponseHead->SetHeaderOverride(nsHttp::Content_Encoding, newEncoding);
+  }
   *aNewNextListener = do_AddRef(nextListener).take();
   return NS_OK;
 }