From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf <jpoimboe@redhat.com>
Date: Mon, 6 Nov 2017 07:21:51 -0600
Subject: [PATCH] objtool: Move kernel headers/code sync check to a script
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CVE-2017-5754

Replace the nasty diff checks in the objtool Makefile with a clean bash
script, and make the warnings more specific.

Heavily inspired by tools/perf/check-headers.sh.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/ab015f15ccd8c0c6008493c3c6ee3d495eaf2927.1509974346.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
(cherry picked from commit a89ec413c623eb2870180bcad678046bf7bc8465)
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
(cherry picked from commit 4e72ce95a057e744b8d580239e2d8afa51118d82)
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 tools/objtool/Makefile      | 16 +---------------
 tools/objtool/sync-check.sh | 29 +++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 15 deletions(-)
 create mode 100755 tools/objtool/sync-check.sh

diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index f95f48e445c3..90b0241f3ccc 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -41,22 +41,8 @@ include $(srctree)/tools/build/Makefile.include
 $(OBJTOOL_IN): fixdep FORCE
 	@$(MAKE) $(build)=objtool
 
-# Busybox's diff doesn't have -I, avoid warning in that case
-#
 $(OBJTOOL): $(LIBSUBCMD) $(OBJTOOL_IN)
-	@(diff -I 2>&1 | grep -q 'option requires an argument' && \
-	test -d ../../kernel -a -d ../../tools -a -d ../objtool && (( \
-	diff arch/x86/lib/insn.c ../../arch/x86/lib/insn.c >/dev/null && \
-	diff arch/x86/lib/inat.c ../../arch/x86/lib/inat.c >/dev/null && \
-	diff arch/x86/lib/x86-opcode-map.txt ../../arch/x86/lib/x86-opcode-map.txt >/dev/null && \
-	diff arch/x86/tools/gen-insn-attr-x86.awk ../../arch/x86/tools/gen-insn-attr-x86.awk >/dev/null && \
-	diff arch/x86/include/asm/insn.h ../../arch/x86/include/asm/insn.h >/dev/null && \
-	diff arch/x86/include/asm/inat.h ../../arch/x86/include/asm/inat.h >/dev/null && \
-	diff arch/x86/include/asm/inat_types.h ../../arch/x86/include/asm/inat_types.h >/dev/null) \
-	|| echo "warning: objtool: x86 instruction decoder differs from kernel" >&2 )) || true
-	@(test -d ../../kernel -a -d ../../tools -a -d ../objtool && (( \
-	diff ../../arch/x86/include/asm/orc_types.h arch/x86/include/asm/orc_types.h >/dev/null) \
-	|| echo "warning: objtool: orc_types.h differs from kernel" >&2 )) || true
+	@./sync-check.sh
 	$(QUIET_LINK)$(CC) $(OBJTOOL_IN) $(LDFLAGS) -o $@
 
 
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
new file mode 100755
index 000000000000..1470e74e9d66
--- /dev/null
+++ b/tools/objtool/sync-check.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+FILES='
+arch/x86/lib/insn.c
+arch/x86/lib/inat.c
+arch/x86/lib/x86-opcode-map.txt
+arch/x86/tools/gen-insn-attr-x86.awk
+arch/x86/include/asm/insn.h
+arch/x86/include/asm/inat.h
+arch/x86/include/asm/inat_types.h
+arch/x86/include/asm/orc_types.h
+'
+
+check()
+{
+	local file=$1
+
+	diff $file ../../$file > /dev/null ||
+		echo "Warning: synced file at 'tools/objtool/$file' differs from latest kernel version at '$file'"
+}
+
+if [ ! -d ../../kernel ] || [ ! -d ../../tools ] || [ ! -d ../objtool ]; then
+	exit 0
+fi
+
+for i in $FILES; do
+  check $i
+done
-- 
2.14.2

