From patchwork Fri Sep 25 00:03:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 11798491 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id BA91A618 for ; Fri, 25 Sep 2020 00:03:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C627238D6 for ; Fri, 25 Sep 2020 00:03:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="Voey/t3k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726808AbgIYADu (ORCPT ); Thu, 24 Sep 2020 20:03:50 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:50000 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726662AbgIYADs (ORCPT ); Thu, 24 Sep 2020 20:03:48 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08P03h7l004840 for ; Thu, 24 Sep 2020 17:03:46 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=IhPP3YpQ1gtUftflrbA4BXufsf9O3iExnIBX7oV37hg=; b=Voey/t3kag3rOXa1EPfRrABkZtypRcDH+mvWJnRvq4pvBbPMyiK2Y8jFQaB0gh3vlz3B QswpJiHzqznzF6CJfelwTzRoLnd4AKIW+ddfFgrpSQG+1m6ByRZq6soG/j97QphfOvM0 lH0ls5VYbUMoBNSLCeDtqd+3dniZcKHG3ao= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 33qsp44w7b-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 24 Sep 2020 17:03:46 -0700 Received: from intmgw003.03.ash8.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 24 Sep 2020 17:03:45 -0700 Received: by devbig005.ftw2.facebook.com (Postfix, from userid 6611) id 1AF9629465FF; Thu, 24 Sep 2020 17:03:44 -0700 (PDT) From: Martin KaFai Lau To: CC: Alexei Starovoitov , Daniel Borkmann , , Lorenz Bauer , Subject: [PATCH v4 bpf-next 01/13] bpf: Move the PTR_TO_BTF_ID check to check_reg_type() Date: Thu, 24 Sep 2020 17:03:44 -0700 Message-ID: <20200925000344.3854828-1-kafai@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200925000337.3853598-1-kafai@fb.com> References: <20200925000337.3853598-1-kafai@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-24_18:2020-09-24,2020-09-24 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 adultscore=0 lowpriorityscore=0 priorityscore=1501 impostorscore=0 mlxlogscore=945 clxscore=1015 phishscore=0 suspectscore=13 spamscore=0 bulkscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009240174 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org check_reg_type() checks whether a reg can be used as an arg of a func_proto. For PTR_TO_BTF_ID, the check is actually not completely done until the reg->btf_id is pointing to a kernel struct that is acceptable by the func_proto. Thus, this patch moves the btf_id check into check_reg_type(). "arg_type" and "arg_btf_id" are passed to check_reg_type() instead of "compatible". The compatible_reg_types[] usage is localized in check_reg_type() now. The "if (!btf_id) verbose(...); " is also removed since it won't happen. Signed-off-by: Martin KaFai Lau Acked-by: Lorenz Bauer Acked-by: John Fastabend --- kernel/bpf/verifier.c | 60 ++++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 29 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 42dee5dcbc74..945fa2b4d096 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4028,19 +4028,27 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { }; static int check_reg_type(struct bpf_verifier_env *env, u32 regno, - const struct bpf_reg_types *compatible) + enum bpf_arg_type arg_type, + const u32 *arg_btf_id) { struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; enum bpf_reg_type expected, type = reg->type; + const struct bpf_reg_types *compatible; int i, j; + compatible = compatible_reg_types[arg_type]; + if (!compatible) { + verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); + return -EFAULT; + } + for (i = 0; i < ARRAY_SIZE(compatible->types); i++) { expected = compatible->types[i]; if (expected == NOT_INIT) break; if (type == expected) - return 0; + goto found; } verbose(env, "R%d type=%s expected=", regno, reg_type_str[type]); @@ -4048,6 +4056,25 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, verbose(env, "%s, ", reg_type_str[compatible->types[j]]); verbose(env, "%s\n", reg_type_str[compatible->types[j]]); return -EACCES; + +found: + if (type == PTR_TO_BTF_ID) { + if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, + *arg_btf_id)) { + verbose(env, "R%d is of type %s but %s is expected\n", + regno, kernel_type_name(reg->btf_id), + kernel_type_name(*arg_btf_id)); + return -EACCES; + } + + if (!tnum_is_const(reg->var_off) || reg->var_off.value) { + verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", + regno); + return -EACCES; + } + } + + return 0; } static int check_func_arg(struct bpf_verifier_env *env, u32 arg, @@ -4057,7 +4084,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, u32 regno = BPF_REG_1 + arg; struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno]; enum bpf_arg_type arg_type = fn->arg_type[arg]; - const struct bpf_reg_types *compatible; enum bpf_reg_type type = reg->type; int err = 0; @@ -4097,35 +4123,11 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, */ goto skip_type_check; - compatible = compatible_reg_types[arg_type]; - if (!compatible) { - verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type); - return -EFAULT; - } - - err = check_reg_type(env, regno, compatible); + err = check_reg_type(env, regno, arg_type, fn->arg_btf_id[arg]); if (err) return err; - if (type == PTR_TO_BTF_ID) { - const u32 *btf_id = fn->arg_btf_id[arg]; - - if (!btf_id) { - verbose(env, "verifier internal error: missing BTF ID\n"); - return -EFAULT; - } - - if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id, *btf_id)) { - verbose(env, "R%d is of type %s but %s is expected\n", - regno, kernel_type_name(reg->btf_id), kernel_type_name(*btf_id)); - return -EACCES; - } - if (!tnum_is_const(reg->var_off) || reg->var_off.value) { - verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n", - regno); - return -EACCES; - } - } else if (type == PTR_TO_CTX) { + if (type == PTR_TO_CTX) { err = check_ctx_reg(env, reg, regno); if (err < 0) return err;