From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1757EC4727F for ; Wed, 30 Sep 2020 11:14:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C185F206F7 for ; Wed, 30 Sep 2020 11:14:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="CVdgttPk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729104AbgI3LO2 (ORCPT ); Wed, 30 Sep 2020 07:14:28 -0400 Received: from mail.skyhub.de ([5.9.137.197]:44820 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725779AbgI3LO2 (ORCPT ); Wed, 30 Sep 2020 07:14:28 -0400 Received: from zn.tnic (p200300ec2f092a005c3b806e425f5e5c.dip0.t-ipconnect.de [IPv6:2003:ec:2f09:2a00:5c3b:806e:425f:5e5c]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 87E181EC0288; Wed, 30 Sep 2020 13:14:26 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1601464466; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=aPWYZ1q3fOniefLzk7p2xWmEpeprxPWws28KMdGZwOA=; b=CVdgttPkl8cmlGmITfxVjU80f3bmKxANJbREmrGNjEY2uNpVjrNh8w8wvIh4Fa90jUhZ8x DZ2HLzEImmqJH0/s0EsXZhkjyJ3n7HThy9MygJlLQLG+yB851PmOahm3zWSUbmIJC5vDRT 48jY8Xvxdh9uIUwBS9fVA5vGk/82tnI= Date: Wed, 30 Sep 2020 13:14:16 +0200 From: Borislav Petkov To: Marc Zyngier Cc: Andrew Morton , Will Deacon , Rabin Vincent , x86-ml , lkml Subject: [PATCH] scripts/decodecode: Add the capability to supply the program counter Message-ID: <20200930111416.GF6810@zn.tnic> References: <20200929113238.GC21110@zn.tnic> <20200929132255.GE21110@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200929132255.GE21110@zn.tnic> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Date: Tue, 29 Sep 2020 18:45:56 +0200 ... so that comparing with objdump output from vmlinux can ease pinpointing where the trapping instruction actually is. An example is better than a thousand words: $ PC=0xffffffff8329a927 ./scripts/decodecode < ~/tmp/syz/gfs2.splat [ 477.379104][T23917] Code: 48 83 ec 28 48 89 3c 24 48 89 54 24 08 e8 c1 b4 4a fe 48 8d bb 00 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 97 05 00 00 48 8b 9b 00 01 00 00 48 85 db 0f 84 All code ======== ffffffff8329a8fd: 48 83 ec 28 sub $0x28,%rsp ffffffff8329a901: 48 89 3c 24 mov %rdi,(%rsp) ffffffff8329a905: 48 89 54 24 08 mov %rdx,0x8(%rsp) ffffffff8329a90a: e8 c1 b4 4a fe callq 0xffffffff81745dd0 ffffffff8329a90f: 48 8d bb 00 01 00 00 lea 0x100(%rbx),%rdi ffffffff8329a916: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax ffffffff8329a91d: fc ff df ffffffff8329a920: 48 89 fa mov %rdi,%rdx ffffffff8329a923: 48 c1 ea 03 shr $0x3,%rdx ffffffff8329a927:* 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction ffffffff8329a92b: 0f 85 97 05 00 00 jne 0xffffffff8329aec8 ffffffff8329a931: 48 8b 9b 00 01 00 00 mov 0x100(%rbx),%rbx ffffffff8329a938: 48 85 db test %rbx,%rbx ffffffff8329a93b: 0f .byte 0xf ffffffff8329a93c: 84 .byte 0x84 Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200929113238.GC21110@zn.tnic --- scripts/decodecode | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/scripts/decodecode b/scripts/decodecode index fbdb325cdf4f..31d884e35f2f 100755 --- a/scripts/decodecode +++ b/scripts/decodecode @@ -6,6 +6,7 @@ # options: set env. variable AFLAGS=options to pass options to "as"; # e.g., to decode an i386 oops on an x86_64 system, use: # AFLAGS=--32 decodecode < 386.oops +# PC=hex - the PC (program counter) the oops points to cleanup() { rm -f $T $T.s $T.o $T.oo $T.aa $T.dis @@ -67,15 +68,19 @@ if [ -z "$ARCH" ]; then esac fi +# Params: (tmp_file, pc_sub) disas() { - ${CROSS_COMPILE}as $AFLAGS -o $1.o $1.s > /dev/null 2>&1 + t=$1 + pc_sub=$2 + + ${CROSS_COMPILE}as $AFLAGS -o $t.o $t.s > /dev/null 2>&1 if [ "$ARCH" = "arm" ]; then if [ $width -eq 2 ]; then OBJDUMPFLAGS="-M force-thumb" fi - ${CROSS_COMPILE}strip $1.o + ${CROSS_COMPILE}strip $t.o fi if [ "$ARCH" = "arm64" ]; then @@ -83,11 +88,18 @@ disas() { type=inst fi - ${CROSS_COMPILE}strip $1.o + ${CROSS_COMPILE}strip $t.o fi - ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $1.o | \ - grep -v "/tmp\|Disassembly\|\.text\|^$" > $1.dis 2>&1 + if [ $pc_sub -ne 0 ]; then + if [ $PC ]; then + adj_vma=$(( $PC - $pc_sub )) + OBJDUMPFLAGS="$OBJDUMPFLAGS --adjust-vma=$adj_vma" + fi + fi + + ${CROSS_COMPILE}objdump $OBJDUMPFLAGS -S $t.o | \ + grep -v "/tmp\|Disassembly\|\.text\|^$" > $t.dis 2>&1 } marker=`expr index "$code" "\<"` @@ -95,14 +107,17 @@ if [ $marker -eq 0 ]; then marker=`expr index "$code" "\("` fi + touch $T.oo if [ $marker -ne 0 ]; then + # 2 opcode bytes and a single space + pc_sub=$(( $marker / 3 )) echo All code >> $T.oo echo ======== >> $T.oo beforemark=`echo "$code"` echo -n " .$type 0x" > $T.s echo $beforemark | sed -e 's/ /,0x/g; s/[<>()]//g' >> $T.s - disas $T + disas $T $pc_sub cat $T.dis >> $T.oo rm -f $T.o $T.s $T.dis @@ -114,7 +129,7 @@ echo =========================================== >> $T.aa code=`echo $code | sed -e 's/ [<(]/ /;s/[>)] / /;s/ /,0x/g; s/[>)]$//'` echo -n " .$type 0x" > $T.s echo $code >> $T.s -disas $T +disas $T 0 cat $T.dis >> $T.aa # (lines of whole $T.oo) - (lines of $T.aa, i.e. "Code starting") + 3, -- 2.21.0 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette