From 93048e5a6f33cc8e2fc547bf65c41551696e23c6 Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Wed, 26 May 2021 09:43:36 +0200
Subject: [PATCH] Remove privilege escalation via seteuid() etc. on Linux.

---
 src/lib/cross.h          |  8 --------
 src/lib/cross_linux.cc   | 36 ------------------------------------
 src/lib/ext.cc           |  4 ----
 test/disk_writer_test.cc |  1 -
 4 files changed, 49 deletions(-)

diff --git a/src/lib/cross.h b/src/lib/cross.h
index b70d84a0e..25b3b3820 100644
--- a/src/lib/cross.h
+++ b/src/lib/cross.h
@@ -71,14 +71,6 @@ namespace dcpomatic {
 	std::string get_process_id ();
 }
 
-class PrivilegeEscalator
-{
-public:
-	PrivilegeEscalator ();
-	~PrivilegeEscalator ();
-
-	static bool test;
-};
 
 /** @class Waker
  *  @brief A class which tries to keep the computer awake on various operating systems.
diff --git a/src/lib/cross_linux.cc b/src/lib/cross_linux.cc
index 326e590b8..65151791c 100644
--- a/src/lib/cross_linux.cc
+++ b/src/lib/cross_linux.cc
@@ -371,7 +371,6 @@ bool
 Drive::unmount ()
 {
 	for (auto i: _mount_points) {
-		PrivilegeEscalator esc;
 		int const r = umount(i.string().c_str());
 		LOG_DISK("Tried to unmount %1 and got %2 and %3", i.string(), r, errno);
 		if (r == -1) {
@@ -382,41 +381,6 @@ Drive::unmount ()
 }
 
 
-void
-unprivileged ()
-{
-	uid_t ruid, euid, suid;
-	if (getresuid(&ruid, &euid, &suid) == -1) {
-		cerr << "getresuid() failed.\n";
-	}
-	if (seteuid(ruid) == -1) {
-		cerr << "seteuid() failed.\n";
-	}
-}
-
-
-bool PrivilegeEscalator::test = false;
-
-
-PrivilegeEscalator::~PrivilegeEscalator ()
-{
-	if (!test) {
-		unprivileged ();
-	}
-}
-
-
-PrivilegeEscalator::PrivilegeEscalator ()
-{
-	if (!test) {
-		int const r = seteuid(0);
-		if (r < 0) {
-			throw PrivilegeError (String::compose("seteuid() call failed with %1", errno));
-		}
-	}
-}
-
-
 boost::filesystem::path
 config_path ()
 {
diff --git a/src/lib/ext.cc b/src/lib/ext.cc
index 86821bfa1..feba68c1f 100644
--- a/src/lib/ext.cc
+++ b/src/lib/ext.cc
@@ -304,10 +304,6 @@ try
 	parts.division[2] = 0;
 	parts.division[3] = 0;
 
-#ifdef DCPOMATIC_LINUX
-	PrivilegeEscalator e;
-#endif
-
 	/* XXX: not sure if disk_id matters */
 	int r = ext4_mbr_write (bd, &parts, 0);
 	if (r) {
diff --git a/test/disk_writer_test.cc b/test/disk_writer_test.cc
index 1146c2e1b..217032d75 100644
--- a/test/disk_writer_test.cc
+++ b/test/disk_writer_test.cc
@@ -98,7 +98,6 @@ BOOST_AUTO_TEST_CASE (disk_writer_test1)
 	/* Some arbitrary file size here */
 	make_random_file (dcp / "foo", 1024 * 1024 * 32 - 6128);
 
-	PrivilegeEscalator::test = true;
 	dcpomatic::write (dcp, disk.string(), partition.string(), 0);
 
 	BOOST_CHECK_EQUAL (system("/sbin/e2fsck -fn build/test/disk_writer_test1.partition"), 0);
-- 
2.30.2