From 34ef5ef21b35342801a45f8f00ca43059846bad4 Mon Sep 17 00:00:00 2001
From: Vincent Brillault <vincent.brillault@cern.ch>
Date: Mon, 8 Jan 2018 12:41:02 +0100
Subject: [PATCH 1/3] Delay umount (for RedHat access to pti_enable)

---
 spectre-meltdown-checker.sh | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 9b78da3..367b3e0 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -199,11 +199,6 @@ case "$ibrs_enabled" in
 	*) pstatus yellow unknown;;
 esac
 
-if [ "$mounted_debugfs" = 1 ]; then
-	# umount debugfs if we did mount it ourselves
-	umount /sys/kernel/debug
-fi
-
 /bin/echo "* Mitigation 2"
 /bin/echo -n "*   Kernel compiled with retpolines: "
 # We check the RETPOLINE kernel options
@@ -301,6 +296,11 @@ else
 	pstatus red NO
 fi
 
+if [ "$mounted_debugfs" = 1 ]; then
+	# umount debugfs if we did mount it ourselves
+	umount /sys/kernel/debug
+fi
+
 /bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
 if grep -q AMD /proc/cpuinfo; then
 	pstatus green "NOT VULNERABLE" "your CPU is not vulnerable as per the vendor"

From 66f77080950dceffef6023054629a208a15220cd Mon Sep 17 00:00:00 2001
From: Vincent Brillault <vincent.brillault@cern.ch>
Date: Mon, 8 Jan 2018 12:39:03 +0100
Subject: [PATCH 2/3] Refactor RedHat support: - Isolate file check to
 different elif (allowing to add more) - Do the PTI debugfs check first
 (faster and supposed to be dynamic) - If pti_enable is 0, don't trust dmesg
 (supposed to be dynamic)

---
 spectre-meltdown-checker.sh | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 367b3e0..f809e0d 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -171,15 +171,20 @@ if [ ! -e /sys/kernel/debug/sched_features ]; then
 	# try to mount the debugfs hierarchy ourselves and remember it to umount afterwards
 	mount -t debugfs debugfs /sys/kernel/debug 2>/dev/null && mounted_debugfs=1
 fi
-if [ -e /sys/kernel/debug/ibrs_enabled -o -e /sys/kernel/debug/x86/ibrs_enabled ]; then
+if [ -e /sys/kernel/debug/ibrs_enabled ]; then
 	# if the file is there, we have IBRS compiled-in
 	pstatus green YES
 	ibrs_supported=1
+	ibrs_enabled=$(cat /sys/kernel/debug/ibrs_enabled 2>/dev/null)
+elif [ -e /sys/kernel/debug/x86/ibrs_enabled ]; then
+	# RedHat uses a different path (see https://access.redhat.com/articles/3311301)
+	pstatus green YES
+	ibrs_supported=1
+	ibrs_enabled=$(cat /sys/kernel/debug/x86/ibrs_enabled 2>/dev/null)
 else
 	pstatus red NO
 fi
 
-[ -f /sys/kernel/debug/ibrs_enabled ] && ibrs_enabled=$(cat /sys/kernel/debug/ibrs_enabled 2>/dev/null) || ibrs_enabled=$(cat /sys/kernel/debug/x86/ibrs_enabled 2>/dev/null)
 /bin/echo -n "*   IBRS enabled for Kernel space: "
 # 0 means disabled
 # 1 is enabled only for kernel space
@@ -285,13 +290,17 @@ if grep ^flags /proc/cpuinfo | grep -qw pti; then
 	# vanilla PTI patch sets the 'pti' flag in cpuinfo
 	pstatus green YES
 	kpti_enabled=1
+elif [ -e /sys/kernel/debug/x86/pti_enabled ]; then
+	# RedHat Backport creates a dedicated file, see https://access.redhat.com/articles/3311301
+	kpti_enabled=$(cat /sys/kernel/debug/x86/pti_enabled 2>/dev/null)
 elif dmesg | grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled'; then
 	# if we can't find the flag, grep in dmesg
-	pstatus green YES
 	kpti_enabled=1
-elif [ -e /sys/kernel/debug/x86/pti_enabled -a "$(cat /sys/kernel/debug/x86/pti_enabled 2>/dev/null)" = 1 ]; then
+else
+	kpti_enabled=0
+fi
+if [ "$kpti_enabled" = 1 ]; then
 	pstatus green YES
-	kpti_enabled=1
 else
 	pstatus red NO
 fi

From a7923489287a2626590f7cecab7f59ea524641c5 Mon Sep 17 00:00:00 2001
From: Vincent Brillault <vincent.brillault@cern.ch>
Date: Mon, 8 Jan 2018 12:54:16 +0100
Subject: [PATCH 3/3] RedHat uses a different configuration name

---
 spectre-meltdown-checker.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index f809e0d..3be2418 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -250,13 +250,13 @@ kpti_can_tell=0
 if [ -e /proc/config.gz ]; then
 	# either the running kernel exports his own config
 	kpti_can_tell=1
-	if zgrep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /proc/config.gz; then
+	if zgrep -q '^\(CONFIG_PAGE_TABLE_ISOLATION=y\|CONFIG_KAISER=y\)' /proc/config.gz; then
 		kpti_support=1
 	fi
 elif [ -e /boot/config-$(uname -r) ]; then
 	# or we can find a config file in /root with the kernel release name
 	kpti_can_tell=1
-	if grep  -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /boot/config-$(uname -r); then
+	if grep  -q '^\(CONFIG_PAGE_TABLE_ISOLATION=y\|CONFIG_KAISER=y\)' /boot/config-$(uname -r); then
 		kpti_support=1
 	fi
 fi