From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Robin Ebert <ebertrobin2002@gmail.com>
Date: Thu, 27 Jan 2022 23:41:41 +0100
Subject: Fix wayland bugs related to bad versioning

Chromium tries to bind to the newest version of some wayland interfaces (output, drm, xdg-exporter). This causes issues when it doesn't actually support the version.
To mitigate this this patch introduces some constants specifing the max supported version and ensures that this value is enforced.
Chromium also tries to map the keymap file descriptor as read-write but new versions of at least wlroots now passes it as read-only.
This is fixed by mapping the file read-only.

diff --git a/ui/ozone/platform/wayland/host/wayland_connection.cc b/ui/ozone/platform/wayland/host/wayland_connection.cc
index 6c0501b0f95fa50ff4fe677cff7354401fb05268..a9a366b54a7490e005357224351b2ae2b40d052e 100644
--- a/ui/ozone/platform/wayland/host/wayland_connection.cc
+++ b/ui/ozone/platform/wayland/host/wayland_connection.cc
@@ -69,10 +69,13 @@ constexpr uint32_t kMaxLinuxDmabufVersion = 3;
 constexpr uint32_t kMaxSeatVersion = 5;
 constexpr uint32_t kMaxShmVersion = 1;
 constexpr uint32_t kMaxXdgShellVersion = 1;
+constexpr uint32_t kMaxWlOutputVersion = 3;
 constexpr uint32_t kMaxDeviceManagerVersion = 3;
 constexpr uint32_t kMaxWpPresentationVersion = 1;
 constexpr uint32_t kMaxWpViewporterVersion = 1;
 constexpr uint32_t kMaxTextInputManagerVersion = 1;
+constexpr uint32_t kMaxXdgExporterVersion = 1;
+constexpr uint32_t kMaxWlDrmVersion = 2;
 constexpr uint32_t kMaxExplicitSyncVersion = 2;
 constexpr uint32_t kMaxXdgDecorationVersion = 1;
 constexpr uint32_t kMaxExtendedDragVersion = 1;
@@ -405,7 +408,7 @@ void WaylandConnection::Global(void* data,
       return;
     }
 
-    wl::Object<wl_output> output = wl::Bind<wl_output>(registry, name, version);
+    wl::Object<wl_output> output = wl::Bind<wl_output>(registry, name, std::min(version, kMaxWlOutputVersion));
     if (!output) {
       LOG(ERROR) << "Failed to bind to wl_output global";
       return;
@@ -502,10 +505,10 @@ void WaylandConnection::Global(void* data,
   } else if (!connection->xdg_foreign_ &&
              strcmp(interface, "zxdg_exporter_v1") == 0) {
     connection->xdg_foreign_ = std::make_unique<XdgForeignWrapper>(
-        connection, wl::Bind<zxdg_exporter_v1>(registry, name, version));
+        connection, wl::Bind<zxdg_exporter_v1>(registry, name, std::min(version, kMaxXdgExporterVersion)));
   } else if (!connection->drm_ && (strcmp(interface, "wl_drm") == 0) &&
              version >= kMinWlDrmVersion) {
-    auto wayland_drm = wl::Bind<struct wl_drm>(registry, name, version);
+    auto wayland_drm = wl::Bind<struct wl_drm>(registry, name, std::min(version, kMaxWlDrmVersion));
     connection->drm_ =
         std::make_unique<WaylandDrm>(wayland_drm.release(), connection);
   } else if (!connection->zaura_shell_ &&
diff --git a/ui/ozone/platform/wayland/host/wayland_keyboard.cc b/ui/ozone/platform/wayland/host/wayland_keyboard.cc
index 85fcd6a423b5af29a1bbd910468778afd28b8c27..462bb1f39b1194a01fd398d8c63f032f8b9d4a0b 100644
--- a/ui/ozone/platform/wayland/host/wayland_keyboard.cc
+++ b/ui/ozone/platform/wayland/host/wayland_keyboard.cc
@@ -7,7 +7,7 @@
 #include <utility>
 
 #include "base/files/scoped_file.h"
-#include "base/memory/unsafe_shared_memory_region.h"
+#include "base/memory/read_only_shared_memory_region.h"
 #include "base/unguessable_token.h"
 #include "ui/base/buildflags.h"
 #include "ui/events/base_event_utils.h"
@@ -119,10 +119,10 @@ void WaylandKeyboard::Keymap(void* data,
   base::ScopedFD fd(keymap_fd);
   auto length = size - 1;
   auto shmen = base::subtle::PlatformSharedMemoryRegion::Take(
-      std::move(fd), base::subtle::PlatformSharedMemoryRegion::Mode::kUnsafe,
+      std::move(fd), base::subtle::PlatformSharedMemoryRegion::Mode::kReadOnly,
       length, base::UnguessableToken::Create());
   auto mapped_memory =
-      base::UnsafeSharedMemoryRegion::Deserialize(std::move(shmen)).Map();
+      base::ReadOnlySharedMemoryRegion::Deserialize(std::move(shmen)).Map();
   const char* keymap = mapped_memory.GetMemoryAs<char>();
 
   if (!keymap || format != WL_KEYBOARD_KEYMAP_FORMAT_XKB_V1)