From patchwork Mon Sep 5 14:33:08 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12966207 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 1FFDCC6FA8B for ; Mon, 5 Sep 2022 14:35:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238435AbiIEOfG (ORCPT ); Mon, 5 Sep 2022 10:35:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238360AbiIEOex (ORCPT ); Mon, 5 Sep 2022 10:34:53 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DD51BE3F; Mon, 5 Sep 2022 07:34:39 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4MLrXT4J64z9v7Nx; Mon, 5 Sep 2022 22:30:33 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwBX0ly8CBZjNGwkAA--.20252S4; Mon, 05 Sep 2022 15:34:11 +0100 (CET) From: Roberto Sassu To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, dhowells@redhat.com, jarkko@kernel.org, rostedt@goodmis.org, mingo@redhat.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, shuah@kernel.org Cc: bpf@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, deso@posteo.net, memxor@gmail.com, Roberto Sassu , Joanne Koong Subject: [PATCH v16 02/12] bpf: Move dynptr type check to is_dynptr_type_expected() Date: Mon, 5 Sep 2022 16:33:08 +0200 Message-Id: <20220905143318.1592015-3-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220905143318.1592015-1-roberto.sassu@huaweicloud.com> References: <20220905143318.1592015-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwBX0ly8CBZjNGwkAA--.20252S4 X-Coremail-Antispam: 1UD129KBjvJXoWxWryxKryktry5trW5JryrJFb_yoWrCw4DpF s7u39FqrW0yF42vw1ftF4kArW5KFy8WrW5CFZ5A340yFyxZr98ZF15Kr1xXrn5KFWkCw43 Aw10vay5Aw1UJFJanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBFb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVWUJVWUCwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV WxJVW8Jr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_ Gr1j6F4UJwAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ew Av7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY 6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28IcxkI7V AKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCj r7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI42IY6x IIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVWxJVW8Jr1lIxAIcVCF 04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7 CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07UC9aPUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQAGBF1jj4KhSAAAsZ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Roberto Sassu Move dynptr type check to is_dynptr_type_expected() from is_dynptr_reg_valid_init(), so that callers can better determine the cause of a negative result (dynamic pointer not valid/initialized, dynamic pointer of the wrong type). It will be useful for example for BTF, to restrict which dynamic pointer types can be passed to kfuncs, as initially only the local type will be supported. Also, splitting makes the code more readable, since checking the dynamic pointer type is not necessarily related to validity and initialization. Split the validity/initialization and dynamic pointer type check also in the verifier, and adjust the expected error message in the test (a test for an unexpected dynptr type passed to a helper cannot be added due to missing suitable helpers, but this case has been tested manually). Cc: Joanne Koong Cc: Kumar Kartikeya Dwivedi Signed-off-by: Roberto Sassu Acked-by: Kumar Kartikeya Dwivedi --- kernel/bpf/verifier.c | 35 ++++++++++++++----- .../testing/selftests/bpf/prog_tests/dynptr.c | 2 +- 2 files changed, 28 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 068b20ed34d2..10b3c0a81d09 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -779,8 +779,8 @@ 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) +static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, + struct bpf_reg_state *reg) { struct bpf_func_state *state = func(env, reg); int spi = get_spi(reg->off); @@ -796,11 +796,24 @@ static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_re return false; } + return true; +} + +static bool is_dynptr_type_expected(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, + enum bpf_arg_type arg_type) +{ + struct bpf_func_state *state = func(env, reg); + enum bpf_dynptr_type dynptr_type; + int spi = get_spi(reg->off); + /* ARG_PTR_TO_DYNPTR takes any type of dynptr */ if (arg_type == ARG_PTR_TO_DYNPTR) return true; - return state->stack[spi].spilled_ptr.dynptr.type == arg_to_dynptr_type(arg_type); + dynptr_type = arg_to_dynptr_type(arg_type); + + return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type; } /* The reg state of a pointer or a bounded scalar was saved when @@ -6050,21 +6063,27 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg, } meta->uninit_dynptr_regno = regno; - } else if (!is_dynptr_reg_valid_init(env, reg, arg_type)) { + } else if (!is_dynptr_reg_valid_init(env, reg)) { + verbose(env, + "Expected an initialized dynptr as arg #%d\n", + arg + 1); + return -EINVAL; + } else if (!is_dynptr_type_expected(env, reg, arg_type)) { const char *err_extra = ""; switch (arg_type & DYNPTR_TYPE_FLAG_MASK) { case DYNPTR_TYPE_LOCAL: - err_extra = "local "; + err_extra = "local"; break; case DYNPTR_TYPE_RINGBUF: - err_extra = "ringbuf "; + err_extra = "ringbuf"; break; default: + err_extra = ""; break; } - - verbose(env, "Expected an initialized %sdynptr as arg #%d\n", + verbose(env, + "Expected a dynptr of type %s as arg #%d\n", err_extra, arg + 1); return -EINVAL; } diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c index bcf80b9f7c27..8fc4e6c02bfd 100644 --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c +++ b/tools/testing/selftests/bpf/prog_tests/dynptr.c @@ -30,7 +30,7 @@ static struct { {"invalid_helper2", "Expected an initialized dynptr as arg #3"}, {"invalid_write1", "Expected an initialized dynptr as arg #1"}, {"invalid_write2", "Expected an initialized dynptr as arg #3"}, - {"invalid_write3", "Expected an initialized ringbuf dynptr as arg #1"}, + {"invalid_write3", "Expected an initialized dynptr as arg #1"}, {"invalid_write4", "arg 1 is an unacquired reference"}, {"invalid_read1", "invalid read from stack"}, {"invalid_read2", "cannot pass in dynptr at an offset"},