From 551e01c124a04f3a5f4b1f4679cdcad96dd5f321 Mon Sep 17 00:00:00 2001
From: Alexandru Croitor <alexandru.croitor@qt.io>
Date: Tue, 23 Jul 2024 12:18:28 +0200
Subject: [PATCH] CMake: Allow opting out of Intel CET hardening

Some Qt internal targets might not work correctly when built with
Intel CET hardening.

Add a per-target opt out to skip adding the Intel CET flags.

Task-number: QTBUG-127464
Change-Id: I1a28b228a82b3505d987649eec6db08281c15482
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
(cherry picked from commit c5e42a9d2faef611e3a6d124d5b093670346fb87)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 cmake/QtFlagHandlingHelpers.cmake | 27 +++++++++++++++++++++++++++
 cmake/QtInternalTargets.cmake     |  9 ++-------
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/cmake/QtFlagHandlingHelpers.cmake b/cmake/QtFlagHandlingHelpers.cmake
index 251a356df0e..3cfab2abf61 100644
--- a/cmake/QtFlagHandlingHelpers.cmake
+++ b/cmake/QtFlagHandlingHelpers.cmake
@@ -235,6 +235,7 @@ function(qt_internal_apply_gc_binaries target visibility)
     endif()
 endfunction()
 
+# Only applied to Bootstrap and BundledPCRE2.
 function(qt_internal_apply_intel_cet target visibility)
     if(NOT QT_FEATURE_intelcet)
         return()
@@ -254,10 +255,36 @@ function(qt_internal_apply_intel_cet target visibility)
             ">:-mshstk>")
     endif()
     if(flags)
+        set(opt_out_condition "$<NOT:$<BOOL:$<TARGET_PROPERTY:_qt_no_intel_cet_harderning>>>")
+        set(flags "$<${opt_out_condition}:${flags}>")
         target_compile_options("${target}" ${visibility} "${flags}")
     endif()
 endfunction()
 
+# Meant to be applied to PlatformCommonInternal.
+function(qt_internal_apply_intel_cet_harderning target)
+    if(NOT QT_FEATURE_intelcet)
+        return()
+    endif()
+
+    set(opt_out_condition "$<NOT:$<BOOL:$<TARGET_PROPERTY:_qt_no_intel_cet_harderning>>>")
+
+    if(MSVC)
+        set(intel_cet_flag "-CETCOMPAT")
+        set(condition "$<${opt_out_condition}:${intel_cet_flag}>")
+        qt_internal_platform_link_options("${target}" INTERFACE "${condition}")
+    else()
+        set(intel_cet_flag "-fcf-protection=full")
+        set(condition "$<${opt_out_condition}:${intel_cet_flag}>")
+        target_compile_options("${target}" INTERFACE "${condition}")
+    endif()
+endfunction()
+
+# Allow opting out of the Intel CET hardening on a per-target basis.
+function(qt_internal_skip_intel_cet_hardening target)
+    set_target_properties("${target}" PROPERTIES _qt_no_intel_cet_harderning TRUE)
+endfunction()
+
 # Sets the exceptions flags for the given target according to exceptions_on
 function(qt_internal_set_exceptions_flags target exceptions_on)
     set(_defs "")
diff --git a/cmake/QtInternalTargets.cmake b/cmake/QtInternalTargets.cmake
index f7b32d18f23..79f7fd9c57f 100644
--- a/cmake/QtInternalTargets.cmake
+++ b/cmake/QtInternalTargets.cmake
@@ -311,13 +311,8 @@ if (GCC AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "9.2")
 endif()
 
 # Hardening options
-if(QT_FEATURE_intelcet)
-    if(MSVC)
-        qt_internal_platform_link_options(PlatformCommonInternal INTERFACE -CETCOMPAT)
-    else()
-        target_compile_options(PlatformCommonInternal INTERFACE -fcf-protection=full)
-    endif()
-endif()
+
+qt_internal_apply_intel_cet_harderning(PlatformCommonInternal)
 
 if(QT_FEATURE_glibc_fortify_source)
     set(is_optimized_build "$<OR:$<NOT:$<CONFIG:Debug>>,$<BOOL:${QT_FEATURE_optimize_debug}>>")