Bug 1619466 - Make the blocklist variable BROWSER_PROCESS work. r=aklotz

The blocklist variable `BROWSER_PROCESS` did not work as expected.  Entries
defined there were blocked not only in the browser process but also in the
child process.

This patch makes sure entries in `BROWSER_PROCESS` are blocked only in the
browser process.

Differential Revision: https://phabricator.services.mozilla.com/D65248

--HG--
extra : moz-landing-system : lando

browser/app/winlauncher/freestanding/DllBlocklist.cpp

@@ -186,6 +186,11 @@ static BlockAction CheckBlockInfo(const DllBlockInfo* aInfo, void* aBaseAddress,
     return BlockAction::Allow;
   }
 
+  if ((aInfo->mFlags & DllBlockInfo::BROWSER_PROCESS_ONLY) &&
+      (gBlocklistInitFlags & eDllBlocklistInitFlagIsChildProcess)) {
+    return BlockAction::Allow;
+  }
+
   if (aInfo->mMaxVersion == DllBlockInfo::ALL_VERSIONS) {
     return BlockAction::Deny;
   }

mozglue/dllservices/WindowsDllBlocklist.cpp

@@ -473,6 +473,11 @@ static NTSTATUS NTAPI patched_LdrLoadDll(PWCHAR filePath, PULONG flags,
         goto continue_loading;
       }
 
+      if ((info->mFlags & DllBlockInfo::BROWSER_PROCESS_ONLY) &&
+          (sInitFlags & eDllBlocklistInitFlagIsChildProcess)) {
+        goto continue_loading;
+      }
+
       unsigned long long fVersion = DllBlockInfo::ALL_VERSIONS;
 
       if (info->mMaxVersion != DllBlockInfo::ALL_VERSIONS) {

mozglue/dllservices/WindowsDllBlocklistCommon.h

@@ -36,10 +36,11 @@ struct DllBlockInfoT {
   // only when we are a child process.
   enum Flags {
     FLAGS_DEFAULT = 0,
-    BLOCK_WIN8PLUS_ONLY = 1,
-    BLOCK_WIN8_ONLY = 2,
-    USE_TIMESTAMP = 4,
-    CHILD_PROCESSES_ONLY = 8
+    BLOCK_WIN8PLUS_ONLY = 1 << 0,
+    BLOCK_WIN8_ONLY = 1 << 1,
+    USE_TIMESTAMP = 1 << 2,
+    CHILD_PROCESSES_ONLY = 1 << 3,
+    BROWSER_PROCESS_ONLY = 1 << 4,
   } mFlags;
 
   bool IsVersionBlocked(const uint64_t aOther) const {

mozglue/dllservices/gen_dll_blocklist_defs.py

@@ -59,6 +59,7 @@ BLOCK_WIN8PLUS_ONLY = 'BLOCK_WIN8PLUS_ONLY'
 BLOCK_WIN8_ONLY = 'BLOCK_WIN8_ONLY'
 USE_TIMESTAMP = 'USE_TIMESTAMP'
 CHILD_PROCESSES_ONLY = 'CHILD_PROCESSES_ONLY'
+BROWSER_PROCESS_ONLY = 'BROWSER_PROCESS_ONLY'
 SUBSTITUTE_LSP_PASSTHROUGH = 'SUBSTITUTE_LSP_PASSTHROUGH'
 
 # Only these flags are available in the input script
@@ -355,12 +356,11 @@ LSP_OUTPUT_SPEC = [
 
 GENERATED_BLOCKLIST_FILES = [
     BlocklistDescriptor('A11y', ['BROWSER_PROCESS'], outspec=A11Y_OUTPUT_SPEC),
-    # Child is not used by anything at the moment, so we'll just leave this
-    # descriptor commented out for now.
-    # BlocklistDescriptor('Child', ['ALL_PROCESSES', 'CHILD_PROCESSES']),
     BlocklistDescriptor('Launcher', ALL_DEFINITION_LISTS, flagspec={
+                        'BROWSER_PROCESS': {BROWSER_PROCESS_ONLY},
                         'CHILD_PROCESSES': {CHILD_PROCESSES_ONLY}}),
     BlocklistDescriptor('Legacy', ALL_DEFINITION_LISTS, flagspec={
+                        'BROWSER_PROCESS': {BROWSER_PROCESS_ONLY},
                         'CHILD_PROCESSES': {CHILD_PROCESSES_ONLY}}),
     # Roughed-in for the moment; we'll enable this in bug 1238735
     # BlocklistDescriptor('LSP', ALL_DEFINITION_LISTS, outspec=LSP_OUTPUT_SPEC),