From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=unavailable 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 85D72C3815B for ; Fri, 17 Apr 2020 10:43:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64740221EA for ; Fri, 17 Apr 2020 10:43:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="HkFdGJH+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729500AbgDQKnP (ORCPT ); Fri, 17 Apr 2020 06:43:15 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:50038 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728868AbgDQKnO (ORCPT ); Fri, 17 Apr 2020 06:43:14 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03HAfpfA009360; Fri, 17 Apr 2020 10:42:58 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=YIWoAje0qyhjK/2S/YVkAhxEbVPEDjaDZZ11p5pY6GU=; b=HkFdGJH+/AZVhHlv/JLptPFLKdNcdq6cte+H53h/7Ha2m0W8BoZIKGy3BA2QIoVtORaY TWVgyo0PznY3lu4dYyhznj0YDn3LOkaTwaB5ziXWjh/NRLFjHwXXAwp/hg+CH6O6gbfJ TvULyc/4ISDCV7QpnuktZaYeinkixQPTFlLeDw1YXsWjGft5Yh82j92SRCEe2D1T9XRU K0yPrh0v8EojQiU78xxLQVn4LEDCYGlLXq3ZR+uTa2iwbAnxcqqmzHIh/Q1b3j6l9YhB vr+KvGKB36kf9QxSZxo1OWTGy12o17gFy3be6sYBKEGn8036FRaZboMJn/fwbXlnVj4e Nw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 30e0aaby11-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Apr 2020 10:42:58 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03HAc4Wp018976; Fri, 17 Apr 2020 10:42:58 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 30dyp28b89-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 17 Apr 2020 10:42:58 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 03HAgu6a015831; Fri, 17 Apr 2020 10:42:57 GMT Received: from localhost.uk.oracle.com (/10.175.205.33) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 17 Apr 2020 03:42:56 -0700 From: Alan Maguire To: ast@kernel.org, daniel@iogearbox.net, yhs@fb.com Cc: kafai@fb.com, songliubraving@fb.com, andriin@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, Alan Maguire Subject: [RFC PATCH bpf-next 2/6] bpf: btf->resolved_[ids,sizes] should not be used for vmlinux BTF Date: Fri, 17 Apr 2020 11:42:36 +0100 Message-Id: <1587120160-3030-3-git-send-email-alan.maguire@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1587120160-3030-1-git-send-email-alan.maguire@oracle.com> References: <1587120160-3030-1-git-send-email-alan.maguire@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9593 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 suspectscore=0 malwarescore=0 phishscore=0 spamscore=0 adultscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004170084 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9593 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 clxscore=1011 impostorscore=0 mlxlogscore=999 mlxscore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 phishscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004170084 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When testing support for print data structures using patches later in this series, I hit NULL pointer dereference bugs when printing "struct sk_buff". The problem seems to revolve around that structure's use of a zero-length array in the middle of the data structure - headers_start[0]. We see in btf_type_id_size() we consult btf->resolved_ids and btf->resolved_sizes; both of which are not used in kernel vmlinux BTF so should not be used when handling vmlinux BTF data. Signed-off-by: Alan Maguire --- kernel/bpf/btf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 50080ad..a474839 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -1170,7 +1170,7 @@ const struct btf_type *btf_type_id_size(const struct btf *btf, if (btf_type_has_size(size_type)) { size = size_type->size; - } else if (btf_type_is_array(size_type)) { + } else if (btf_type_is_array(size_type) && btf->resolved_sizes) { size = btf->resolved_sizes[size_type_id]; } else if (btf_type_is_ptr(size_type)) { size = sizeof(void *); @@ -1179,6 +1179,9 @@ const struct btf_type *btf_type_id_size(const struct btf *btf, !btf_type_is_var(size_type))) return NULL; + if (!btf->resolved_ids) + return NULL; + size_type_id = btf->resolved_ids[size_type_id]; size_type = btf_type_by_id(btf, size_type_id); if (btf_type_nosize_or_null(size_type)) -- 1.8.3.1