PKGBUILDs/extra/firefox/0002-Bug-1660901-Support-the-fstat-like-subset-of-fstatat.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jed Davis <jld@mozilla.com>
Date: Fri, 28 Aug 2020 09:23:58 +0000
Subject: [PATCH] Bug 1660901 - Support the fstat-like subset of fstatat in the
 Linux sandbox policies. r=gcp

Differential Revision: https://phabricator.services.mozilla.com/D88499
---
 security/sandbox/linux/SandboxFilter.cpp           | 6 ++++++
 security/sandbox/linux/broker/SandboxBrokerUtils.h | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/security/sandbox/linux/SandboxFilter.cpp b/security/sandbox/linux/SandboxFilter.cpp
index e522d61e065c..4087bdc07e01 100644
--- a/security/sandbox/linux/SandboxFilter.cpp
+++ b/security/sandbox/linux/SandboxFilter.cpp
@@ -243,6 +243,12 @@ class SandboxPolicyCommon : public SandboxPolicyBase {
     auto path = reinterpret_cast<const char*>(aArgs.args[1]);
     auto buf = reinterpret_cast<statstruct*>(aArgs.args[2]);
     auto flags = static_cast<int>(aArgs.args[3]);
+
+    if (fd != AT_FDCWD && (flags & AT_EMPTY_PATH) != 0 &&
+        strcmp(path, "") == 0) {
+      return ConvertError(fstatsyscall(fd, buf));
+    }
+
     if (fd != AT_FDCWD && path[0] != '/') {
       SANDBOX_LOG_ERROR("unsupported fd-relative fstatat(%d, \"%s\", %p, %d)",
                         fd, path, buf, flags);
diff --git a/security/sandbox/linux/broker/SandboxBrokerUtils.h b/security/sandbox/linux/broker/SandboxBrokerUtils.h
index 85a006740c2c..db33b5028e77 100644
--- a/security/sandbox/linux/broker/SandboxBrokerUtils.h
+++ b/security/sandbox/linux/broker/SandboxBrokerUtils.h
@@ -19,10 +19,12 @@
 typedef struct stat64 statstruct;
 #  define statsyscall stat64
 #  define lstatsyscall lstat64
+#  define fstatsyscall fstat64
 #elif defined(__NR_stat)
 typedef struct stat statstruct;
 #  define statsyscall stat
 #  define lstatsyscall lstat
+#  define fstatsyscall fstat
 #else
 #  error Missing stat syscall include.
 #endif