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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 280F7C4724C for ; Thu, 30 Apr 2020 15:06:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 052F32082E for ; Thu, 30 Apr 2020 15:06:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588259183; bh=/UyCzO9R9fysl4kZeByYlY2bTx7o+gO18EaAwq+xbyY=; h=Subject:To:Cc:From:Date:List-ID:From; b=mZR7UW/TqMzGcmp5KO2bcf26YUSh4wt0pvlpmJ3hhSvdVLzpjFda8Y9zYn7e5KuDV IfWZ8WH3X6VMLeQsiQ5rVBf243bftDwMhg4CflU0HfWfwsZMx4vS7nzoQmJ9jADx3o jBC3++ht/VWml720PWjKeXWiAUKzc01h34T3cujU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726530AbgD3PGW (ORCPT ); Thu, 30 Apr 2020 11:06:22 -0400 Received: from wforward1-smtp.messagingengine.com ([64.147.123.30]:49483 "EHLO wforward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726377AbgD3PGW (ORCPT ); Thu, 30 Apr 2020 11:06:22 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.west.internal (Postfix) with ESMTP id 4C19F879; Thu, 30 Apr 2020 11:06:21 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute1.internal (MEProxy); Thu, 30 Apr 2020 11:06:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=0WTL63 hkSbAqQ9BNzEV5waoFOoE+2xaZoawZYCPaslg=; b=RM+qoz6/LMwiIc+l/M5F1D SYMOEraqN+riMBtvb8Yr2CMY+RmifTJXiZlk9uAmov6IwTgIPiMtLUZ8fzU6wFqR 74YaQdmT5D6bvYv98QRvQuXvIOePeTHECTHh/6ejHBYlCBSm3TTTwomeUVVBLcLK UJgRtJcPtMZomrr46FBG6pEeuek6lU1pX+iM+jgSBQisIVae8of9P4rNOqhol9IY 8hmzlU50WmR1/YlqVgPOsdJ/PYHTxmE7+FGF2ivsbfBfkF8wIRjHEgf2lHWCdfTX ccFbmtWh9uTQI6IfzZlgXhfvyHn9uomCItlZnp2intBenROBcZ2oCE6drf4NYlBg == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduhedrieehgdekfecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucggtffrrghtthgvrhhnpeelleelvdegfeelledtteegudegfffghfduffduudekge efleegieegkeejhfelveenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeek fedrkeeirdekledruddtjeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmh grihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id 4BF7B3065F31; Thu, 30 Apr 2020 11:06:20 -0400 (EDT) Subject: FAILED: patch "[PATCH] bpf, x86: Fix encoding for lower 8-bit registers in BPF_STX" failed to apply to 4.4-stable tree To: lukenels@cs.washington.edu, ast@kernel.org, luke.r.nels@gmail.com, xi.wang@gmail.com Cc: From: Date: Thu, 30 Apr 2020 17:06:15 +0200 Message-ID: <1588259175185252@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From aee194b14dd2b2bde6252b3acf57d36dccfc743a Mon Sep 17 00:00:00 2001 From: Luke Nelson Date: Sat, 18 Apr 2020 16:26:53 -0700 Subject: [PATCH] bpf, x86: Fix encoding for lower 8-bit registers in BPF_STX BPF_B This patch fixes an encoding bug in emit_stx for BPF_B when the source register is BPF_REG_FP. The current implementation for BPF_STX BPF_B in emit_stx saves one REX byte when the operands can be encoded using Mod-R/M alone. The lower 8 bits of registers %rax, %rbx, %rcx, and %rdx can be accessed without using a REX prefix via %al, %bl, %cl, and %dl, respectively. Other registers, (e.g., %rsi, %rdi, %rbp, %rsp) require a REX prefix to use their 8-bit equivalents (%sil, %dil, %bpl, %spl). The current code checks if the source for BPF_STX BPF_B is BPF_REG_1 or BPF_REG_2 (which map to %rdi and %rsi), in which case it emits the required REX prefix. However, it misses the case when the source is BPF_REG_FP (mapped to %rbp). The result is that BPF_STX BPF_B with BPF_REG_FP as the source operand will read from register %ch instead of the correct %bpl. This patch fixes the problem by fixing and refactoring the check on which registers need the extra REX byte. Since no BPF registers map to %rsp, there is no need to handle %spl. Fixes: 622582786c9e0 ("net: filter: x86: internal BPF JIT") Signed-off-by: Xi Wang Signed-off-by: Luke Nelson Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200418232655.23870-1-luke.r.nels@gmail.com diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 5ea7c2cf7ab4..42b6709e6dc7 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -158,6 +158,19 @@ static bool is_ereg(u32 reg) BIT(BPF_REG_AX)); } +/* + * is_ereg_8l() == true if BPF register 'reg' is mapped to access x86-64 + * lower 8-bit registers dil,sil,bpl,spl,r8b..r15b, which need extra byte + * of encoding. al,cl,dl,bl have simpler encoding. + */ +static bool is_ereg_8l(u32 reg) +{ + return is_ereg(reg) || + (1 << reg) & (BIT(BPF_REG_1) | + BIT(BPF_REG_2) | + BIT(BPF_REG_FP)); +} + static bool is_axreg(u32 reg) { return reg == BPF_REG_0; @@ -598,9 +611,8 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off) switch (size) { case BPF_B: /* Emit 'mov byte ptr [rax + off], al' */ - if (is_ereg(dst_reg) || is_ereg(src_reg) || - /* We have to add extra byte for x86 SIL, DIL regs */ - src_reg == BPF_REG_1 || src_reg == BPF_REG_2) + if (is_ereg(dst_reg) || is_ereg_8l(src_reg)) + /* Add extra byte for eregs or SIL,DIL,BPL in src_reg */ EMIT2(add_2mod(0x40, dst_reg, src_reg), 0x88); else EMIT1(0x88);