From patchwork Tue Aug 9 13:45:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12939639 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 C672AC25B07 for ; Tue, 9 Aug 2022 13:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244288AbiHINqp (ORCPT ); Tue, 9 Aug 2022 09:46:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244223AbiHINqn (ORCPT ); Tue, 9 Aug 2022 09:46:43 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75EA4DEA3; Tue, 9 Aug 2022 06:46:42 -0700 (PDT) Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4M2DnB3FhMz6880F; Tue, 9 Aug 2022 21:43:58 +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; Tue, 9 Aug 2022 15:46:39 +0200 From: Roberto Sassu To: , , , , , , , , , , , , , , , , , , , CC: , , , , , , Roberto Sassu , Joanne Koong Subject: [PATCH v9 03/10] btf: Handle dynamic pointer parameter in kfuncs Date: Tue, 9 Aug 2022 15:45:56 +0200 Message-ID: <20220809134603.1769279-4-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220809134603.1769279-1-roberto.sassu@huawei.com> References: <20220809134603.1769279-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) 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 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 | 17 +++++++++++++++++ kernel/bpf/verifier.c | 4 ++-- 3 files changed, 22 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 67dfc728fbf8..17cca396c89f 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6363,6 +6363,8 @@ 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 = btf_type_is_struct(ref_t) && + !strcmp(ref_tname, "bpf_dynptr_kern"); /* Permit pointer to mem, but only when argument * type is pointer to scalar, or struct composed @@ -6372,6 +6374,7 @@ 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", @@ -6379,6 +6382,20 @@ 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 843a966cd02b..3c52246a1ceb 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);