From patchwork Fri Sep 17 18:29:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Marchevsky X-Patchwork-Id: 12502929 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 X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFBD7C433F5 for ; Fri, 17 Sep 2021 18:30:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7AE161244 for ; Fri, 17 Sep 2021 18:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240608AbhIQSbg (ORCPT ); Fri, 17 Sep 2021 14:31:36 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:49696 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242445AbhIQSbe (ORCPT ); Fri, 17 Sep 2021 14:31:34 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 18HGQ7b6010813 for ; Fri, 17 Sep 2021 11:30:12 -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=/XZq3XANIDF98Hn2lbHJ7+XBRPZqQwz9YLnU+BTvmss=; b=lL3rcOTd19dL4WWEKYGv1/8KGjnuzTxGfHXywHEbiCq2arSlZS+b5PMqgYx2LxH7ac5I RhqShW0i7Nrgy8ejP91P/X2GtRDP7CPZtvs4P04PQMUhdx6/FJt5h3c65VqDiACyo/gV ImEKehbHVfnXsn2kY/EFH1+Tfw+t27Tb15U= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3b4xhe0vcf-13 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 17 Sep 2021 11:30:11 -0700 Received: from intmgw001.38.frc1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Fri, 17 Sep 2021 11:30:05 -0700 Received: by devbig030.frc3.facebook.com (Postfix, from userid 158236) id 953FE6BF3240; Fri, 17 Sep 2021 11:29:22 -0700 (PDT) From: Dave Marchevsky To: CC: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Yonghong Song , , Dave Marchevsky Subject: [PATCH v6 bpf-next 9/9] bpf: Clarify data_len param in bpf_snprintf and bpf_seq_printf comments Date: Fri, 17 Sep 2021 11:29:11 -0700 Message-ID: <20210917182911.2426606-10-davemarchevsky@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210917182911.2426606-1-davemarchevsky@fb.com> References: <20210917182911.2426606-1-davemarchevsky@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-FB-Source: Intern X-Proofpoint-GUID: UcVEBaIsKqP_ovw2d6Pp482GLZMICPJU X-Proofpoint-ORIG-GUID: UcVEBaIsKqP_ovw2d6Pp482GLZMICPJU X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.391,FMLib:17.0.607.475 definitions=2021-09-17_07,2021-09-17_02,2020-04-07_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 impostorscore=0 mlxlogscore=643 adultscore=0 mlxscore=0 bulkscore=0 phishscore=0 spamscore=0 priorityscore=1501 suspectscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109170110 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Since the data_len in these two functions is a byte len of the preceding u64 *data array, it must always be a multiple of 8. If this isn't the case both helpers error out, so let's make the requirement explicit so users don't need to infer it. Signed-off-by: Dave Marchevsky Acked-by: Andrii Nakryiko --- include/uapi/linux/bpf.h | 5 +++-- tools/include/uapi/linux/bpf.h | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 98ca79a67937..6fc59d61937a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4046,7 +4046,7 @@ union bpf_attr { * arguments. The *data* are a **u64** array and corresponding format string * values are stored in the array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* array. - * The *data_len* is the size of *data* in bytes. + * The *data_len* is the size of *data* in bytes - must be a multiple of 8. * * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory. * Reading kernel memory may fail due to either invalid address or @@ -4751,7 +4751,8 @@ union bpf_attr { * Each format specifier in **fmt** corresponds to one u64 element * in the **data** array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* - * array. The *data_len* is the size of *data* in bytes. + * array. The *data_len* is the size of *data* in bytes - must be + * a multiple of 8. * * Formats **%s** and **%p{i,I}{4,6}** require to read kernel * memory. Reading kernel memory may fail due to either invalid diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 98ca79a67937..6fc59d61937a 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4046,7 +4046,7 @@ union bpf_attr { * arguments. The *data* are a **u64** array and corresponding format string * values are stored in the array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* array. - * The *data_len* is the size of *data* in bytes. + * The *data_len* is the size of *data* in bytes - must be a multiple of 8. * * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory. * Reading kernel memory may fail due to either invalid address or @@ -4751,7 +4751,8 @@ union bpf_attr { * Each format specifier in **fmt** corresponds to one u64 element * in the **data** array. For strings and pointers where pointees * are accessed, only the pointer values are stored in the *data* - * array. The *data_len* is the size of *data* in bytes. + * array. The *data_len* is the size of *data* in bytes - must be + * a multiple of 8. * * Formats **%s** and **%p{i,I}{4,6}** require to read kernel * memory. Reading kernel memory may fail due to either invalid