From patchwork Mon Sep 21 12:12:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenz Bauer X-Patchwork-Id: 1368311 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=cloudflare.com header.i=@cloudflare.com header.a=rsa-sha256 header.s=google header.b=In/nYtmF; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4Bw3Hj2YFYz9sTW for ; Mon, 21 Sep 2020 22:13:21 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726690AbgIUMNU (ORCPT ); Mon, 21 Sep 2020 08:13:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726611AbgIUMNT (ORCPT ); Mon, 21 Sep 2020 08:13:19 -0400 Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE68BC0613D1 for ; Mon, 21 Sep 2020 05:13:18 -0700 (PDT) Received: by mail-wm1-x342.google.com with SMTP id b79so12395829wmb.4 for ; Mon, 21 Sep 2020 05:13:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+Qf5LrUrrFDb7ZG/DC+Ibysm2jzcOs3sVRYjuHbV+04=; b=In/nYtmFwJzMbBug5p7vdYS0mHscrMy/mUPclVvZH7QWrY+KakdP/YsmU2wTir43lv cPPI56SI/FBvhemkEjnGe7L5ZPngZuXznkdyGiXx+QKhsLLGBPi751wNECTe1Jv63fau UBN09GaOJYaBeX2pNbzQMMcyGdKp0J6X1KqdM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+Qf5LrUrrFDb7ZG/DC+Ibysm2jzcOs3sVRYjuHbV+04=; b=Fh+2EnYw6SnSMAH88cDWy/AuD38bEgLk0N8ZgzI0Mw8mBfILNZuYwk7Zz+pDXePYu/ MkWnCtdZya48qIgX0xCrEnXVJ/PbiBFzInjmukzpzlK5Ml5iHwv6SjBS8IbqwcAHCnAx oxMvknEmbFu/wIFR/JXbTY0PtEWwu7qLNf0ud5xV+g7jCIKQaiVuIOZpQA3GVlW7Z9BL EXEAHvYHIN4y2r0Lp89ROywhoALbLL+Gn3a6mBXlfKhPjGxwo5KVyTUO4FMT2+PCx+i2 F3j065BCu65PhCd8aKImIyPUSreTGPqNDEX5WjOY4hO0EgOO8waMjmwR+lcIq+NaPUB/ GsmQ== X-Gm-Message-State: AOAM533yaZmlEee50UW8CNAnNeMiS8GZ2xs3/EZj8dtYyLkwpoSUryJv imk6sbmyI/PgS876KutBKlucMw== X-Google-Smtp-Source: ABdhPJzynkzl86XscjoKSbryUrk4hodhxiSLWtSLy+3c8NwhJbhOzuStSQNHpNtaeqho7eHUEEWjKg== X-Received: by 2002:a1c:6341:: with SMTP id x62mr30056809wmb.70.1600690397457; Mon, 21 Sep 2020 05:13:17 -0700 (PDT) Received: from antares.lan (5.4.6.2.d.5.3.3.f.8.1.6.b.2.d.8.f.f.6.2.a.5.a.7.0.b.8.0.1.0.0.2.ip6.arpa. [2001:8b0:7a5a:26ff:8d2b:618f:335d:2645]) by smtp.gmail.com with ESMTPSA id t15sm18466557wmj.15.2020.09.21.05.13.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Sep 2020 05:13:16 -0700 (PDT) From: Lorenz Bauer To: ast@kernel.org, daniel@iogearbox.net Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Lorenz Bauer , Andrii Nakryiko Subject: [PATCH bpf-next v4 02/11] bpf: check scalar or invalid register in check_helper_mem_access Date: Mon, 21 Sep 2020 13:12:18 +0100 Message-Id: <20200921121227.255763-3-lmb@cloudflare.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200921121227.255763-1-lmb@cloudflare.com> References: <20200921121227.255763-1-lmb@cloudflare.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Move the check for a NULL or zero register to check_helper_mem_access. This makes check_stack_boundary easier to understand. Signed-off-by: Lorenz Bauer Acked-by: Andrii Nakryiko --- kernel/bpf/verifier.c | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 814bc6c1ad16..c997f81c500b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3594,18 +3594,6 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno, struct bpf_func_state *state = func(env, reg); int err, min_off, max_off, i, j, slot, spi; - if (reg->type != PTR_TO_STACK) { - /* Allow zero-byte read from NULL, regardless of pointer type */ - if (zero_size_allowed && access_size == 0 && - register_is_null(reg)) - return 0; - - verbose(env, "R%d type=%s expected=%s\n", regno, - reg_type_str[reg->type], - reg_type_str[PTR_TO_STACK]); - return -EACCES; - } - if (tnum_is_const(reg->var_off)) { min_off = max_off = reg->var_off.value + reg->off; err = __check_stack_boundary(env, regno, min_off, access_size, @@ -3750,9 +3738,19 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, access_size, zero_size_allowed, "rdwr", &env->prog->aux->max_rdwr_access); - default: /* scalar_value|ptr_to_stack or invalid ptr */ + case PTR_TO_STACK: return check_stack_boundary(env, regno, access_size, zero_size_allowed, meta); + default: /* scalar_value or invalid ptr */ + /* Allow zero-byte read from NULL, regardless of pointer type */ + if (zero_size_allowed && access_size == 0 && + register_is_null(reg)) + return 0; + + verbose(env, "R%d type=%s expected=%s\n", regno, + reg_type_str[reg->type], + reg_type_str[PTR_TO_STACK]); + return -EACCES; } }