From patchwork Tue Jan 12 17:55:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rabin Vincent X-Patchwork-Id: 566664 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 A573A14032F for ; Wed, 13 Jan 2016 04:55:25 +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=aH7IIPS6; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753543AbcALRzV (ORCPT ); Tue, 12 Jan 2016 12:55:21 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:36633 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752252AbcALRzU (ORCPT ); Tue, 12 Jan 2016 12:55:20 -0500 Received: by mail-wm0-f67.google.com with SMTP id l65so32586084wmf.3 for ; Tue, 12 Jan 2016 09:55:19 -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; bh=1LKqq0z/NnqyN0ZHRSCIeR7ZOiGiqYWX/FCKFL+49bo=; b=aH7IIPS67NW0w3nRHCn4JBHpoSjv/1zxxQIt5UHxDN3cekDlFa/rVEeDwQUtmOxz5i 12AzZtBno3cIqreBoi9lSUrH9Gt2NqTxZUOkIwndMZl98Xbz9rt8qSEUJmXWmDQXAhSV 5R3qOcFO6511bww7uebbI5Q3n1NzHv+lKyX+gwLlwUXo23FFWe3A1TxEBkfMW2Q3INHA q9tgrYNyt4eze9AZyhhc4jfcQYBra+FPmZxVtTfkaBErHleQ0b9qZMn2i5TCIbA/924l PROxTLadMF6YYkJCZaVqssxPFLILXgyR8G0O7LUJYheZWByJf6M7ZmOauJSOKrLzaGFz Tapg== X-Received: by 10.194.86.166 with SMTP id q6mr122540042wjz.69.1452621319010; Tue, 12 Jan 2016 09:55:19 -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 l194sm18668714wmb.14.2016.01.12.09.55.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 12 Jan 2016 09:55:18 -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: [PATCH] net: bpf: reject invalid shifts Date: Tue, 12 Jan 2016 18:55:07 +0100 Message-Id: <1452621307-2213-1-git-send-email-rabin@rab.in> X-Mailer: git-send-email 2.6.4 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 then in the eBPF verifier and the classic BPF filter checker, for all architectures. Signed-off-by: Rabin Vincent --- 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..3643df0dfaa9 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) && + 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: