From patchwork Thu Jul 14 19:14:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12918449 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBA1FCCA47B for ; Thu, 14 Jul 2022 19:21:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240097AbiGNTVt (ORCPT ); Thu, 14 Jul 2022 15:21:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240104AbiGNTVs (ORCPT ); Thu, 14 Jul 2022 15:21:48 -0400 Received: from sinsgout.his.huawei.com (sinsgout.his.huawei.com [119.8.179.247]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87E7543E58 for ; Thu, 14 Jul 2022 12:21:47 -0700 (PDT) Received: from sinmsgout01.his.huawei.com (unknown [172.28.115.139]) by sinsgout.his.huawei.com (SkyGuard) with ESMTP id 4LkPN10yvxz5RkBr for ; Fri, 15 Jul 2022 03:15:45 +0800 (CST) Received: from fraeml714-chm.china.huawei.com (unknown [172.18.156.147]) by sinmsgout01.his.huawei.com (SkyGuard) with ESMTP id 4LkPGH6vn7z9xFC0; Fri, 15 Jul 2022 03:10:47 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 14 Jul 2022 21:15:34 +0200 From: Roberto Sassu To: , , , , , , , CC: , Roberto Sassu , Joanne Koong Subject: [RFC][PATCH v8 03/12] btf: Handle dynamic pointer parameter in kfuncs Date: Thu, 14 Jul 2022 21:14:46 +0200 Message-ID: <20220714191455.2101834-4-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220714191455.2101834-1-roberto.sassu@huawei.com> References: <20220714191455.2101834-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC Allow the bpf_dynptr_kern parameter to be specified in kfuncs. Also, ensure that the dynamic pointer is valid and initialized. Cc: Joanne Koong Signed-off-by: Roberto Sassu --- include/linux/bpf_verifier.h | 3 +++ kernel/bpf/btf.c | 16 ++++++++++++++++ kernel/bpf/verifier.c | 4 ++-- 3 files changed, 21 insertions(+), 2 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index 2e3bad8640dc..55876fbdbae2 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -560,6 +560,9 @@ int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state u32 regno); int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg, u32 regno, u32 mem_size); +bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, + enum bpf_arg_type arg_type); /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */ static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog, diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index e6fc01de7e50..9e94571d1626 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6353,6 +6353,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, if (is_kfunc) { bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]); + bool arg_dynptr = !strcmp(ref_tname, "bpf_dynptr_kern"); /* Permit pointer to mem, but only when argument * type is pointer to scalar, or struct composed @@ -6362,6 +6363,7 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, */ if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(log, btf, ref_t, 0) && + !arg_dynptr && (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) { bpf_log(log, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n", @@ -6369,6 +6371,20 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env, return -EINVAL; } + /* Assume initialized dynptr. */ + if (arg_dynptr) { + if (!is_dynptr_reg_valid_init(env, reg, + ARG_PTR_TO_DYNPTR)) { + bpf_log(log, + "arg#%d pointer type %s %s must be initialized\n", + i, btf_type_str(ref_t), + ref_tname); + return -EINVAL; + } + + continue; + } + /* Check for mem, len pair */ if (arg_mem_size) { if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 328cfab3af60..d71c43ee9374 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -773,8 +773,8 @@ static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_ return true; } -static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg, - enum bpf_arg_type arg_type) +bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg, + enum bpf_arg_type arg_type) { struct bpf_func_state *state = func(env, reg); int spi = get_spi(reg->off);