From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9BAED433BF for ; Sat, 9 Mar 2024 18:40:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710009608; cv=none; b=hK2JWKQ4YAWb0qNnqyAvtYlu6FPrBz+KFJUCzBN6u9FWUZz1MqiemLVTCMPg374gYQ8ILcv8GlYj14r/elnKIomXnfffWhiBoxqPEoHnYTwx8MXOdhKhwHFFYk30BoFUUQCaQp5FAiHMYyeklk/yIj1WJX3+aZZV9gNDodtcumU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710009608; c=relaxed/simple; bh=Gq2G9WmQB1sPfcnHKSskMF2yZQoskC/VEwYohApjYpg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MoH+tvGrPx0NeoCvMN0QHB9qApIR21bE+00Rmvq5IN0+4FX3ZXMZnQLhQPwtliybHK1Fw0PnCy1Yl4tqVv7Ze5x4Sf5+iuQkQTUTN8s7ZIhGdQrvF0RgEyZx/q01aYo0CM1w9Ic0w3FFNyUQ+Py4onDGTKXD34t9HINxoWXUc5c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=TQoWKGhm; arc=none smtp.client-ip=95.215.58.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="TQoWKGhm" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1710009602; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=d301d2m3XDvxeh+akGWbgzGVsCoHY8gOYz/lNFtWHIw=; b=TQoWKGhm5C//gZsmffhD16ar/68c54m8RhVAk4AS48mThExV9bUk1xaI0fMQcyZX8JkrKm do+8Co52LJq5hID79B2DhSvmKbgeV5Y6VXkjzfcup4Fjz12fUCgL7WViZEA07dqSoFvGK9 x/RXHxq5vvF3KEYVkf2PgK9GdntSGDs= Date: Sat, 9 Mar 2024 10:39:54 -0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next 1/5] bpf: Allow helper bpf_get_ns_current_pid_tgid() in cgroup and sk_msg programs Content-Language: en-GB To: Andrii Nakryiko Cc: bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , John Fastabend , kernel-team@fb.com, Martin KaFai Lau , Yury Namgung References: <20240307232659.1115872-1-yonghong.song@linux.dev> <20240307232705.1116787-1-yonghong.song@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Yonghong Song In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 3/8/24 5:06 PM, Andrii Nakryiko wrote: > On Thu, Mar 7, 2024 at 3:27 PM Yonghong Song wrote: >> Currently bpf_get_current_pid_tgid() is allowed in tracing, cgroup >> and sk_msg progs while bpf_get_ns_current_pid_tgid() is only allowed >> in tracing progs. >> >> We have an internal use case where for an application running >> in a container (with pid namespace), user wants to get >> the pid associated with the pid namespace in a cgroup bpf >> program. Currently, cgroup bpf progs already allow >> bpf_get_current_pid_tgid(). Let us allow bpf_get_ns_current_pid_tgid() >> as well. >> >> With auditing the code, bpf_get_current_pid_tgid() is also used >> by sk_msg prog. So I added bpf_get_ns_current_pid_tgid() >> support for sk_msg prog, so now for all places where >> bpf_get_current_pid_tgid() can be used, bpf_get_ns_current_pid_tgid() >> can be used as well. >> > If tracing can call both bpf_get_current_pid_tgid() and > bpf_get_ns_current_pid_tgid(), can't we just add both into > bpf_base_func_proto() and have them available for all types of BPF > programs? If it's safe for tracing, it's safe for any program type, so > why not? Do we need any capability to control bpf_get_[ns_]current_pid_tgid()? nothing or CAP_BPF or CAP_PERFMON? In my opinion, pid/tgid is available to user space and there is no leaking kernel private data here, so bpf prog should be able to use it in all prog types. I will wait for a few days. If no people object, I will incorporate this in v2. > >> Signed-off-by: Yonghong Song >> --- >> kernel/bpf/cgroup.c | 2 ++ >> net/core/filter.c | 2 ++ >> 2 files changed, 4 insertions(+) >> >> diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c >> index 5a568bbbeaeb..375b92204881 100644 >> --- a/kernel/bpf/cgroup.c >> +++ b/kernel/bpf/cgroup.c >> @@ -2577,6 +2577,8 @@ cgroup_current_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) >> return &bpf_get_current_uid_gid_proto; >> case BPF_FUNC_get_current_pid_tgid: >> return &bpf_get_current_pid_tgid_proto; >> + case BPF_FUNC_get_ns_current_pid_tgid: >> + return &bpf_get_ns_current_pid_tgid_proto; >> case BPF_FUNC_get_current_comm: >> return &bpf_get_current_comm_proto; >> #ifdef CONFIG_CGROUP_NET_CLASSID >> diff --git a/net/core/filter.c b/net/core/filter.c >> index 8adf95765cdd..d4e43303a66b 100644 >> --- a/net/core/filter.c >> +++ b/net/core/filter.c >> @@ -8344,6 +8344,8 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) >> return &bpf_get_current_uid_gid_proto; >> case BPF_FUNC_get_current_pid_tgid: >> return &bpf_get_current_pid_tgid_proto; >> + case BPF_FUNC_get_ns_current_pid_tgid: >> + return &bpf_get_ns_current_pid_tgid_proto; >> case BPF_FUNC_sk_storage_get: >> return &bpf_sk_storage_get_proto; >> case BPF_FUNC_sk_storage_delete: >> -- >> 2.43.0 >>