File 0001-Opt-in-via-CMake-to-allow-privilege-escalation.patch of Package failed_hotspot
From 9f279095a8f66be1d830a504a2768b87d26dfb52 Mon Sep 17 00:00:00 2001
From: Milian Wolff <milian.wolff@kdab.com>
Date: Mon, 13 Mar 2023 17:22:05 +0100
Subject: [PATCH] Opt-in via CMake to allow privilege escalation
Matthias Gerstner from Suse found a TOCTOU security vulnerability
in our privilege escalation code. If abused, the temporary escalation
would remain permanent and opens the door for attackers to wreak
havoc. As this is an optional feature, let's disable it by default
until I find the time to resolve this differently.
See CVE-2023-28144 for more information, the gist is, to quote
Matthias:
> The script contains the following logic during early startup:
>
> if [ ! -z "$1" ]; then
> olduser=$(stat -c '%u' "$1")
> chown "$(whoami)" "$1"
> echo "rewriting to $1"
> # redirect output to file, to enable parsing of output even when
> # the graphical sudo helper like kdesudo isn't forwarding the text properly
> $0 2>&1 | tee -a "$1"
> chown "$olduser" "$1"
> exit
> fi
>
> The two `chown` invocations on the temporary file result in a temporary change
> of the ownership of the temporary file to root, which is originally owned by
> the unprivileged user. So it changes ownership of the provided path first to
> `root`, then reexecutes itself, then changes ownership back to the original
> user.
>
> This offers the following attack vectors:
>
> - giving ownership of an arbitrary file to root
> - giving ownership of an arbitrary file to the unprivileged user
Thanks a lot for Matthias and Suse for detecting this issue and
bringing it to my attention.
---
CMakeLists.txt | 2 ++
hotspot-config.h.cmake | 2 ++
src/perfrecord.cpp | 7 ++++++-
src/perfrecord.h | 1 +
src/recordpage.cpp | 11 +++++++----
5 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4eb5c9f..608c68d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -26,6 +26,8 @@ endif()
set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
+option(ALLOW_PRIVILEGE_ESCALATION "allow temporary privilege escalation" OFF)
+
# Enable the test harness
enable_testing()
diff --git a/hotspot-config.h.cmake b/hotspot-config.h.cmake
index d529f22..a9b664c 100644
--- a/hotspot-config.h.cmake
+++ b/hotspot-config.h.cmake
@@ -28,3 +28,5 @@
#cmakedefine01 KGraphViewerPart_FOUND
#cmakedefine01 KF5SyntaxHighlighting_FOUND
+
+#cmakedefine01 ALLOW_PRIVILEGE_ESCALATION
diff --git a/src/perfrecord.cpp b/src/perfrecord.cpp
index d721045..c02a30a 100644
--- a/src/perfrecord.cpp
+++ b/src/perfrecord.cpp
@@ -109,7 +109,7 @@ static bool privsAlreadyElevated()
void PerfRecord::startRecording(bool elevatePrivileges, const QStringList& perfOptions, const QString& outputPath,
const QStringList& recordOptions, const QString& workingDirectory)
{
- if (elevatePrivileges && geteuid() != 0 && !privsAlreadyElevated()) {
+ if (canElevatePrivileges() && elevatePrivileges && geteuid() != 0 && !privsAlreadyElevated()) {
// elevate privileges temporarily as root
// use kauth/kdesudo to start the elevate_perf_privileges.sh script
// then parse its output and once we get the "waiting..." line the privileges got elevated
@@ -495,6 +495,11 @@ bool PerfRecord::canCompress()
return Zstd_FOUND && perfBuildOptions().contains("zstd: [ on ]");
}
+bool PerfRecord::canElevatePrivileges()
+{
+ return ALLOW_PRIVILEGE_ESCALATION && (!sudoUtil().isEmpty() || KF5Auth_FOUND);
+}
+
bool PerfRecord::isPerfInstalled()
{
return !QStandardPaths::findExecutable(QStringLiteral("perf")).isEmpty();
diff --git a/src/perfrecord.h b/src/perfrecord.h
index 9a8e3f8..b9a580e 100644
--- a/src/perfrecord.h
+++ b/src/perfrecord.h
@@ -39,6 +39,7 @@ public:
static bool canSwitchEvents();
static bool canUseAio();
static bool canCompress();
+ static bool canElevatePrivileges();
static QStringList offCpuProfilingOptions();
diff --git a/src/recordpage.cpp b/src/recordpage.cpp
index c8838ec..149559c 100644
--- a/src/recordpage.cpp
+++ b/src/recordpage.cpp
@@ -371,7 +371,7 @@ RecordPage::RecordPage(QWidget* parent)
if (m_perfRecord->currentUsername() == QLatin1String("root")) {
ui->elevatePrivilegesCheckBox->setChecked(true);
ui->elevatePrivilegesCheckBox->setEnabled(false);
- } else if (m_perfRecord->sudoUtil().isEmpty() && !KF5Auth_FOUND) {
+ } else if (!PerfRecord::canElevatePrivileges()) {
ui->elevatePrivilegesCheckBox->setChecked(false);
ui->elevatePrivilegesCheckBox->setEnabled(false);
ui->elevatePrivilegesCheckBox->setText(
@@ -383,7 +383,8 @@ RecordPage::RecordPage(QWidget* parent)
restoreCombobox(config(), QStringLiteral("applications"), ui->applicationName->comboBox());
restoreCombobox(config(), QStringLiteral("eventType"), ui->eventTypeBox, {ui->eventTypeBox->currentText()});
restoreCombobox(config(), QStringLiteral("customOptions"), ui->perfParams);
- ui->elevatePrivilegesCheckBox->setChecked(config().readEntry(QStringLiteral("elevatePrivileges"), false));
+ ui->elevatePrivilegesCheckBox->setChecked(PerfRecord::canElevatePrivileges()
+ && config().readEntry(QStringLiteral("elevatePrivileges"), false));
ui->offCpuCheckBox->setChecked(config().readEntry(QStringLiteral("offCpuProfiling"), false));
ui->sampleCpuCheckBox->setChecked(config().readEntry(QStringLiteral("sampleCpu"), true));
ui->mmapPagesSpinBox->setValue(config().readEntry(QStringLiteral("mmapPages"), 0));
@@ -754,10 +755,12 @@ void RecordPage::updateRecordType()
m_perfOutput->setInputVisible(recordType == LaunchApplication);
m_perfOutput->clear();
- ui->elevatePrivilegesCheckBox->setEnabled(recordType != ProfileSystem);
+ ui->elevatePrivilegesCheckBox->setEnabled(PerfRecord::canElevatePrivileges() && recordType != ProfileSystem);
ui->sampleCpuCheckBox->setEnabled(recordType != ProfileSystem && PerfRecord::canSampleCpu());
if (recordType == ProfileSystem) {
- ui->elevatePrivilegesCheckBox->setChecked(true);
+ if (PerfRecord::canElevatePrivileges()) {
+ ui->elevatePrivilegesCheckBox->setChecked(true);
+ }
ui->sampleCpuCheckBox->setChecked(true && PerfRecord::canSampleCpu());
}
--
2.39.2
