From patchwork Tue Jan 12 19:17:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rabin Vincent X-Patchwork-Id: 566714 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 5AF361401B5 for ; Wed, 13 Jan 2016 06:17:31 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b=wMIvtgfL; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752307AbcALTR1 (ORCPT ); Tue, 12 Jan 2016 14:17:27 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:33783 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752170AbcALTR0 (ORCPT ); Tue, 12 Jan 2016 14:17:26 -0500 Received: by mail-wm0-f67.google.com with SMTP id u188so32910443wmu.0 for ; Tue, 12 Jan 2016 11:17:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=9lKMT4fpEJyiVUZdhYsfrXIu9w1eZBx4FoqabNd+xiM=; b=wMIvtgfL7laCwIrNMs7jrDKnA0J4CfgLCQ3Jgx+3M+ucQBl5szcxWIK3pJikEAGngg +6e6XAiGJ/FPv0tDFOV+1HaIB2Ih5mqA5jUaDhH1OYF6LpYkxU/DiMFa+TfNXt9eCOfP BRxrSD9oAVI+YQog5w2QEPdBL1qzNPXlE0Zbz9kW9E0heBRUkoxPcmVdqUs0Rxo1mkpY if4i0a9aDZg7DiJGLdAgau6BFmSIP7lmcjuy87Rj4KqXE3KB32Uk35uG/IiRVdbBIIYd CAPdGI8vEELHCBI595cBO07i/avhGcoNYOUxF+UsI1WrL5Pq96nVoqLUBnKcaSNU3ACj faGg== X-Received: by 10.28.158.74 with SMTP id h71mr21021822wme.74.1452626244927; Tue, 12 Jan 2016 11:17:24 -0800 (PST) Received: from localhost.localdomain (90-231-144-194-no56.tbcn.telia.com. [90.231.144.194]) by smtp.gmail.com with ESMTPSA id n5sm18892522wmf.3.2016.01.12.11.17.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 12 Jan 2016 11:17:24 -0800 (PST) From: Rabin Vincent To: davem@davemloft.net Cc: netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, linux-arm-kernel@lists.infradead.org, Rabin Vincent Subject: [PATCHv2] net: bpf: reject invalid shifts Date: Tue, 12 Jan 2016 20:17:08 +0100 Message-Id: <1452626228-15742-1-git-send-email-rabin@rab.in> X-Mailer: git-send-email 2.6.4 In-Reply-To: <20160112185121.GA34045@ast-mbp.thefacebook.com> References: <20160112185121.GA34045@ast-mbp.thefacebook.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On ARM64, a BUG() is triggered in the eBPF JIT if a filter with a constant shift that can't be encoded in the immediate field of the UBFM/SBFM instructions is passed to the JIT. Since these shifts amounts, which are negative or >= regsize, are invalid, reject them in the eBPF verifier and the classic BPF filter checker, for all architectures. Signed-off-by: Rabin Vincent Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- v2: handle BPF_ARSH too kernel/bpf/verifier.c | 10 ++++++++++ net/core/filter.c | 5 +++++ 2 files changed, 15 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a7945d10b378..d1d3e8f57de9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1121,6 +1121,16 @@ static int check_alu_op(struct verifier_env *env, struct bpf_insn *insn) return -EINVAL; } + if ((opcode == BPF_LSH || opcode == BPF_RSH || + opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) { + int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32; + + if (insn->imm < 0 || insn->imm >= size) { + verbose("invalid shift %d\n", insn->imm); + return -EINVAL; + } + } + /* pattern match 'bpf_add Rx, imm' instruction */ if (opcode == BPF_ADD && BPF_CLASS(insn->code) == BPF_ALU64 && regs[insn->dst_reg].type == FRAME_PTR && diff --git a/net/core/filter.c b/net/core/filter.c index 672eefbfbe99..37157c4c1a78 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -777,6 +777,11 @@ static int bpf_check_classic(const struct sock_filter *filter, if (ftest->k == 0) return -EINVAL; break; + case BPF_ALU | BPF_LSH | BPF_K: + case BPF_ALU | BPF_RSH | BPF_K: + if (ftest->k >= 32) + return -EINVAL; + break; case BPF_LD | BPF_MEM: case BPF_LDX | BPF_MEM: case BPF_ST: