From 90d57b6808a58d46802ee83cab70ed802b42e680 Mon Sep 17 00:00:00 2001
From: Eric Curtin <ecurtin@redhat.com>
Date: Tue, 7 Mar 2023 10:24:49 +0000
Subject: [PATCH] Fix for systems with page size larger than 4k

Discovered on Fedora Asahi Remix by Asahi Lina.
---
 chromium-110-LargerThan4k.patch | 86 +++++++++++++++++++++++++++++++++
 chromium.spec                   |  4 ++
 2 files changed, 90 insertions(+)
 create mode 100644 chromium-110-LargerThan4k.patch

diff --git a/chromium-110-LargerThan4k.patch b/chromium-110-LargerThan4k.patch
new file mode 100644
index 0000000..374f487
--- /dev/null
+++ b/chromium-110-LargerThan4k.patch
@@ -0,0 +1,86 @@
+From 96ee2a8e20bb7a7c4fb19e27dc31ff5c6a472849 Mon Sep 17 00:00:00 2001
+From: Ryan Gonzalez <rymg19@gmail.com>
+Date: Mon, 06 Mar 2023 20:22:25 -0600
+Subject: [PATCH] AddressTrackerLinux: Increase the message buffer size
+
+On non-4k-page systems, the message sizes may be too large to fit into
+the buffer, resulting in MSG_TRUNC. Instead of using the fixed 4kb size,
+follow the kernel documentation guidelines as to how large the buffer
+should be.
+
+Originally found by Asahi Lina:
+
+https://vt.social/@lina/109976892758680822
+
+Bug: None
+Change-Id: I4790435190167a706fa7490ab57706db1f4a6120
+---
+
+diff --git a/net/base/address_tracker_linux.cc b/net/base/address_tracker_linux.cc
+index 4976cae..f1a1fff 100644
+--- a/net/base/address_tracker_linux.cc
++++ b/net/base/address_tracker_linux.cc
+@@ -14,6 +14,7 @@
+ #include "base/files/scoped_file.h"
+ #include "base/functional/callback_helpers.h"
+ #include "base/logging.h"
++#include "base/memory/page_size.h"
+ #include "base/posix/eintr_wrapper.h"
+ #include "base/task/current_thread.h"
+ #include "base/threading/scoped_blocking_call.h"
+@@ -323,8 +324,30 @@
+   *address_changed = false;
+   *link_changed = false;
+   *tunnel_changed = false;
+-  char buffer[4096];
+   bool first_loop = true;
++
++  // Varying sources have different opinions regarding the buffer size needed
++  // for netlink messages to avoid truncation:
++  // - The official documentation on netlink says messages are generally 8kb
++  //   or the system page size, whichever is *larger*:
++  //   https://www.kernel.org/doc/html/v6.2/userspace-api/netlink/intro.html#buffer-sizing
++  // - The kernel headers would imply that messages are generally the system
++  //   page size or 8kb, whichever is *smaller*:
++  //   https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/include/linux/netlink.h?h=v6.2.2#n226
++  //   (libmnl follows this.)
++  // - The netlink(7) man page's example always uses a fixed size 8kb buffer:
++  //   https://man7.org/linux/man-pages/man7/netlink.7.html
++  // Here, we follow the guidelines in the documentation, for two primary
++  // reasons:
++  // - Erring on the side of a larger size is the safer way to go to avoid
++  //   MSG_TRUNC.
++  // - Since this is heap-allocated anyway, there's no risk to the stack by
++  //   using the larger size.
++
++  constexpr size_t kMinNetlinkBufferSize = 8 * 1024;
++  std::vector<char> buffer(
++      std::max(base::GetPageSize(), kMinNetlinkBufferSize));
++
+   {
+     absl::optional<base::ScopedBlockingCall> blocking_call;
+     if (tracking_) {
+@@ -334,9 +357,10 @@
+     }
+ 
+     for (;;) {
+-      int rv = HANDLE_EINTR(recv(netlink_fd_.get(), buffer, sizeof(buffer),
+-                                 // Block the first time through loop.
+-                                 first_loop ? 0 : MSG_DONTWAIT));
++      int rv =
++          HANDLE_EINTR(recv(netlink_fd_.get(), buffer.data(), buffer.size(),
++                            // Block the first time through loop.
++                            first_loop ? 0 : MSG_DONTWAIT));
+       first_loop = false;
+       if (rv == 0) {
+         LOG(ERROR) << "Unexpected shutdown of NETLINK socket.";
+@@ -348,7 +372,8 @@
+         PLOG(ERROR) << "Failed to recv from netlink socket";
+         return;
+       }
+-      HandleMessage(buffer, rv, address_changed, link_changed, tunnel_changed);
++      HandleMessage(buffer.data(), rv, address_changed, link_changed,
++                    tunnel_changed);
+     }
+   }
+   if (*link_changed || *address_changed)
diff --git a/chromium.spec b/chromium.spec
index 8c8cd9b..94535f3 100644
--- a/chromium.spec
+++ b/chromium.spec
@@ -385,6 +385,8 @@ Patch143: chromium-110-v8-gcc.patch
 Patch144: chromium-111-v8-std-layout1.patch
 Patch145: chromium-111-v8-std-layout2.patch
 
+Patch146: chromium-110-LargerThan4k.patch
+
 # VAAPI
 # Upstream turned VAAPI on in Linux in 86
 Patch202: chromium-104.0.5112.101-enable-hardware-accelerated-mjpeg.patch
@@ -1000,6 +1002,8 @@ udev.
 %patch144 -p1 -b .v8-std-layout1
 %patch145 -p1 -b .v8-std-layout2
 
+%patch146 -p1 -b .LargerThan4k
+
 %if %{use_qt}
 %patch121 -p1 -b .enable-allowqt
 %endif