From patchwork Wed Aug 31 16:54:35 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12961091 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 96C35C3DA6B for ; Wed, 31 Aug 2022 16:56:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232343AbiHaQ4W (ORCPT ); Wed, 31 Aug 2022 12:56:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59126 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231821AbiHaQ4H (ORCPT ); Wed, 31 Aug 2022 12:56:07 -0400 Received: from frasgout13.his.huawei.com (frasgout13.his.huawei.com [14.137.139.46]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AAD5D99F1; Wed, 31 Aug 2022 09:56:02 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout13.his.huawei.com (SkyGuard) with ESMTP id 4MHqtM75Rpz9xFgJ; Thu, 1 Sep 2022 00:50:35 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP2 (Coremail) with SMTP id GxC2BwBX0lxfkg9jJXIRAA--.5993S4; Wed, 31 Aug 2022 17:55:34 +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 v15 02/12] bpf: Move dynptr type check to is_dynptr_type_expected() Date: Wed, 31 Aug 2022 18:54:35 +0200 Message-Id: <20220831165445.1071641-3-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220831165445.1071641-1-roberto.sassu@huaweicloud.com> References: <20220831165445.1071641-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 X-CM-TRANSID: GxC2BwBX0lxfkg9jJXIRAA--.5993S4 X-Coremail-Antispam: 1UD129KBjvJXoWxWryxKryktry5trW5JryrJFb_yoWrCw4DpF s7u39FqrW0yF42vw1ftF4kArZ8Kry8WrW5CrZ5A340yFyxZr98uF15Kr17Xrn5KFWkCw43 Aw10vay5Aw1UJFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPqb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28IrcIa0xkI8VA2jI8067AKxVWUXw A2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxS w2x7M28EF7xvwVC0I7IYx2IY67AKxVW8JVW5JwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxV W8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4UJVWxJr1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2 WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkE bVWUJVW8JwACjcxG0xvY0x0EwIxGrwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7 AKxVW8ZVWrXwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02 F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_Wr ylIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVW8JVW5JwCI42IY6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Gr0_Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x 07j7hLnUUUUU= X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQABBF1jj4J6BAAAsJ X-CFilter-Loop: Reflected Precedence: bulk List-ID: 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 --- 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 0194a36d0b36..bebb64423acb 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"},