From ef7c0d7ec5525d2ae7cc3bc73548164ec756d3e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Lesimple?= <speed47_github@speed47.net>
Date: Sun, 7 Jan 2018 16:16:11 +0100
Subject: [PATCH] add variant 1 check

---
 spectre-meltdown-checker.sh | 77 +++++++++++++++++++++++++++++++++++--
 1 file changed, 73 insertions(+), 4 deletions(-)

diff --git a/spectre-meltdown-checker.sh b/spectre-meltdown-checker.sh
index 22bab38..6b052d0 100755
--- a/spectre-meltdown-checker.sh
+++ b/spectre-meltdown-checker.sh
@@ -16,15 +16,85 @@ pstatus()
 	/bin/echo
 }
 
+# ----------------------------------------------------------------------
+# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
+#
+# Inspired from extract-ikconfig
+# (c) 2009,2010 Dick Streefland <dick@streefland.net>
+#
+# (c) 2011      Corentin Chary <corentin.chary@gmail.com>
+#
+# Licensed under the GNU General Public License, version 2 (GPLv2).
+# ----------------------------------------------------------------------
+
+check_vmlinux()
+{
+	file "$1" 2>/dev/null | grep -q ELF || return 1
+	return 0
+}
+
+try_decompress()
+{
+        # The obscure use of the "tr" filter is to work around older versions of
+        # "grep" that report the byte offset of the line instead of the pattern.
+
+        # Try to find the header ($1) and decompress from here
+        for     pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"`
+        do
+                pos=${pos%%:*}
+                tail -c+$pos "$img" | $3 > $vmlinuxtmp 2> /dev/null
+                check_vmlinux $vmlinuxtmp && echo $vmlinuxtmp || rm -f $vmlinuxtmp
+        done
+}
+
+extract_vmlinux()
+{
+	img="$1"
+
+	# Prepare temp files:
+	vmlinuxtmp=$(mktemp /tmp/vmlinux-XXX)
+
+	# Initial attempt for uncompressed images or objects:
+	check_vmlinux $img
+
+	# That didn't work, so retry after decompression.
+	try_decompress '\037\213\010' xy    gunzip     || \
+	try_decompress '\3757zXZ\000' abcde unxz       || \
+	try_decompress 'BZh'          xy    bunzip2    || \
+	try_decompress '\135\0\0\0'   xxx   unlzma     || \
+	try_decompress '\211\114\132' xy    'lzop -d'
+}
+
+
 /bin/echo "Spectre and Meltdown mitigation detection tool v$VERSION"
 /bin/echo
 
 # SPECTRE 1
 /bin/echo -e "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m"
-/bin/echo -n "* Kernel recompiled with LFENCE opcode insertion: "
-pstatus yellow UNKNOWN "check not yet implemented"
+/bin/echo -n "* Kernel compiled with LFENCE opcode inserted at the proper places: "
+
+vmlinux=$(extract_vmlinux /boot/vmlinuz-4.4.110)
+status=0
+if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
+	pstatus yellow UNKNOWN "couldn't extract your kernel"
+elif ! which objdump >/dev/null 2>&1; then
+	pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package"
+else
+	nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
+	if [ "$nb_lfence" -lt 50 ]; then
+		pstatus red NO "only $nb_lfence lfence opcodes found, should be >= 50"
+		status=1
+	else
+		pstatus green YES "$nb_lfence opcodes found, which is >= 50"
+		status=2
+	fi
+	rm -f $vmlinux
+fi
+
 /bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
-pstatus yellow UNKNOWN "not implemented, but real answer is most probably VULNERABLE at this stage"
+[ "$status" = 0 ] && pstatus yellow UNKNOWN
+[ "$status" = 1 ] && pstatus red VULNERABLE
+[ "$status" = 2 ] && pstatus green 'NOT VULNERABLE'
 
 
 # VARIANT 2
@@ -153,4 +223,3 @@ if [ "$USER" != root ]; then
 	/bin/echo "You can try the following command: sudo $0"
 fi
 
-