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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 984E1C64E7C for ; Wed, 2 Dec 2020 18:05:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 314AF221FC for ; Wed, 2 Dec 2020 18:05:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728834AbgLBSFn (ORCPT ); Wed, 2 Dec 2020 13:05:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbgLBSFm (ORCPT ); Wed, 2 Dec 2020 13:05:42 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8507FC0613CF for ; Wed, 2 Dec 2020 10:05:02 -0800 (PST) Received: from zn.tnic (p200300ec2f161b00329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ec:2f16:1b00:329c:23ff:fea6:a903]) (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 E9EF21EC04D6; Wed, 2 Dec 2020 19:05:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1606932301; 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=TE/OHmqT8H79QFUkFqfZpqHgm6sL6Er/QHxIG08YOvs=; b=Lt95ZAietdiaN+EX4738+KleeNMsD1BTxd979xsP3J6hW1i7w3xjnAy/cYxdgA2WsbqbaI rKF88mEp2+JHkQbWr2CEyhAzUL8m3DZE1RbF/pSpILclcy5CkyGgMGVoOUjee57OuWgFcK 6h3i/W1wSRS/SPW6lifjufD9dY60veg= Date: Wed, 2 Dec 2020 19:04:56 +0100 From: Borislav Petkov To: Masami Hiramatsu Cc: Andy Lutomirski , X86 ML , LKML Subject: Re: [RFC PATCH v0 00/19] x86/insn: Add an insn_decode() API Message-ID: <20201202180456.GH2951@zn.tnic> References: <20201124101952.7909-1-bp@alien8.de> <20201124174647.GI4009@zn.tnic> <20201129175005.7e07a9f799e888ffd5f4ed67@kernel.org> <20201130134442.GB6019@zn.tnic> <20201201022145.48201fe165a28cb0e1f042ae@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201201022145.48201fe165a28cb0e1f042ae@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 01, 2020 at 02:21:45AM +0900, Masami Hiramatsu wrote: > Because it overruns the buffer. Maybe -E2BIG/ENODATA or any other > error (except for -EINVAL) is OK :) ENODATA it is. :) And propagating that error value is easy because the err_out: labels are all coming from the validate_next() error path so we basically know that the buffer has ended. ./insn_sanity: Success: decoded and checked 10000 random instructions with 0 errors (seed:0x7bdfa56e) insn buffer: 0x48 0xcf 0x48 0x83 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 0x90 supplied buf size: 15, ret 0 supplied buf size: 2, ret 0 supplied buf size: 3, ret 0 supplied buf size: 4, ret 0 insn_decode: entry insn_decode: will get_length insn_get_immediate: getting immediate insn_get_displacement: getting displacement insn_get_sib: getting sib insn_get_modrm: entry insn_get_opcode: entry insn_get_prefixes: entry, prefixes->got: 0 insn_get_prefixes: 1 insn_get_prefixes: REX insn_get_prefixes: VEX insn_get_prefixes: validate_next: 0 insn_get_prefixes: insn->next_byte: 0x7ffc211eb661, insn->end_kaddr: 0x7ffc211eb661 insn_get_prefixes: errored out supplied buf size: 1, ret -61 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette