From patchwork Fri Dec 3 05:30:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 12654293 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 3F1FFC433F5 for ; Fri, 3 Dec 2021 05:14:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231481AbhLCFSK (ORCPT ); Fri, 3 Dec 2021 00:18:10 -0500 Received: from szxga02-in.huawei.com ([45.249.212.188]:27338 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbhLCFSK (ORCPT ); Fri, 3 Dec 2021 00:18:10 -0500 Received: from dggpeml500025.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4J51GM6m5GzbjLJ; Fri, 3 Dec 2021 13:14:35 +0800 (CST) Received: from huawei.com (10.175.124.27) by dggpeml500025.china.huawei.com (7.185.36.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Fri, 3 Dec 2021 13:14:44 +0800 From: Hou Tao To: Alexei Starovoitov CC: Martin KaFai Lau , Yonghong Song , Daniel Borkmann , Andrii Nakryiko , , , Subject: [PATCH bpf-next v5] bpf: disallow BPF_LOG_KERNEL log level for bpf(BPF_BTF_LOAD) Date: Fri, 3 Dec 2021 13:30:01 +0800 Message-ID: <20211203053001.740945-1-houtao1@huawei.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500025.china.huawei.com (7.185.36.35) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load() to set log level as BPF_LOG_KERNEL. The same checking has already been done in bpf_check(), so factor out a helper to check the validity of log attributes and use it in both places. Fixes: 8580ac9404f6 ("bpf: Process in-kernel BTF") Signed-off-by: Hou Tao Acked-by: Yonghong Song Acked-by: Martin KaFai Lau --- v5: * rebased on bpf-next * patch #1 "bpf: Clean-up bpf_verifier_vlog() for BPF_LOG_KERNEL log level" has been merged, so drop it * doesn't pass max_total to bpf_verifier_log_attr_valid() because now the max log buffer size of btf and verifier are the same. v4: https://www.spinics.net/lists/bpf/msg50807.html * rebased on bpf-next * add Acked-by tags v3: https://www.spinics.net/lists/bpf/msg48992.html * rebased on bpf-next * address comments from Daniel Borkmann: patch #1: add prefix "BPF: " instead of "BPF:" for error message patch #2: remove uncessary parenthesis, keep the max buffer length setting of btf verifier, and add Fixes tag. v2: https://www.spinics.net/lists/bpf/msg48809.html * rebased on bpf-next * patch #1: add a trailing newline if needed (suggested by Martin) * add patch #2 v1: https://www.spinics.net/lists/bpf/msg48550.html --- include/linux/bpf_verifier.h | 7 +++++++ kernel/bpf/btf.c | 3 +-- kernel/bpf/verifier.c | 6 +++--- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index c8a78e830fca..182b16a91084 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -396,6 +396,13 @@ static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log) log->level == BPF_LOG_KERNEL); } +static inline bool +bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log) +{ + return log->len_total >= 128 && log->len_total <= UINT_MAX >> 2 && + log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK); +} + #define BPF_MAX_SUBPROGS 256 struct bpf_subprog_info { diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index ed4258cb0832..d442dc07a8a1 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4473,8 +4473,7 @@ static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size, log->len_total = log_size; /* log attributes have to be sane */ - if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 || - !log->level || !log->ubuf) { + if (!bpf_verifier_log_attr_valid(log)) { err = -EINVAL; goto errout; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6522ffdea487..1126b75fe650 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14050,11 +14050,11 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr) log->ubuf = (char __user *) (unsigned long) attr->log_buf; log->len_total = attr->log_size; - ret = -EINVAL; /* log attributes have to be sane */ - if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 || - !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK) + if (!bpf_verifier_log_attr_valid(log)) { + ret = -EINVAL; goto err_unlock; + } } if (IS_ERR(btf_vmlinux)) {