From nobody Sat Apr 11 20:14:10 2026 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 C13E2C00140 for ; Wed, 10 Aug 2022 06:59:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231426AbiHJG7h (ORCPT ); Wed, 10 Aug 2022 02:59:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231409AbiHJG7R (ORCPT ); Wed, 10 Aug 2022 02:59:17 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DE5EF72EFA for ; Tue, 9 Aug 2022 23:59:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660114753; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s/g1jGP9DmVuf1qGmI16BGeQdTRGm51fgmAVNuH3Cg8=; b=fcZG0t7/HGtd0hIjm7lxpGpGvZoSrbGs+F428w1C7cBIAdTo9YqV4hJWpKI3hzEHN4nqKC lzZ1HlUNHryDKXCBAEmBZAbnZC88MUfJF9ZbhM2z41GD7XqwSqsIXwWOVcmn5ata439tY3 NFu0Df9aPNPD2ZakLrascWQUlleyjjE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-125-fIfyWb7CPO-V6M-yVKGyoQ-1; Wed, 10 Aug 2022 02:59:09 -0400 X-MC-Unique: fIfyWb7CPO-V6M-yVKGyoQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 25D513C0F394; Wed, 10 Aug 2022 06:59:08 +0000 (UTC) Received: from shodan.usersys.redhat.com (unknown [10.43.17.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D6DC1C15BA1; Wed, 10 Aug 2022 06:59:07 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id D768D1C00A9; Wed, 10 Aug 2022 08:59:06 +0200 (CEST) From: Artem Savkov To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , bpf@vger.kernel.org, netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrea Arcangeli , Daniel Vacek , Jiri Olsa , Song Liu , Daniel Xu , Kumar Kartikeya Dwivedi , Artem Savkov Subject: [PATCH bpf-next v5 1/3] bpf: add destructive kfunc flag Date: Wed, 10 Aug 2022 08:59:03 +0200 Message-Id: <20220810065905.475418-2-asavkov@redhat.com> In-Reply-To: <20220810065905.475418-1-asavkov@redhat.com> References: <20220810065905.475418-1-asavkov@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add KF_DESTRUCTIVE flag for destructive functions. Functions with this flag set will require CAP_SYS_BOOT capabilities. Signed-off-by: Artem Savkov --- Documentation/bpf/kfuncs.rst | 9 +++++++++ include/linux/btf.h | 3 ++- kernel/bpf/verifier.c | 5 +++++ 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/Documentation/bpf/kfuncs.rst b/Documentation/bpf/kfuncs.rst index c8b21de1c772..781731749e55 100644 --- a/Documentation/bpf/kfuncs.rst +++ b/Documentation/bpf/kfuncs.rst @@ -152,6 +152,15 @@ ensure the integrity of the operation being performed = on the expected object. The KF_SLEEPABLE flag is used for kfuncs that may sleep. Such kfuncs can o= nly be called by sleepable BPF programs (BPF_F_SLEEPABLE). =20 +2.4.7 KF_DESTRUCTIVE flag +-------------------------- + +The KF_DESTRUCTIVE flag is used to indicate functions calling which is +destructive to the system. For example such a call can result in system +rebooting or panicking. Due to this additional restrictions apply to these +calls. At the moment they only require CAP_SYS_BOOT capability, but more c= an be +added later. + 2.5 Registering the kfuncs -------------------------- =20 diff --git a/include/linux/btf.h b/include/linux/btf.h index 976cbdd2981f..ad93c2d9cc1c 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -49,7 +49,8 @@ * for this case. */ #define KF_TRUSTED_ARGS (1 << 4) /* kfunc only takes trusted pointer argum= ents */ -#define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */ +#define KF_SLEEPABLE (1 << 5) /* kfunc may sleep */ +#define KF_DESTRUCTIVE (1 << 6) /* kfunc performs destructive actions */ =20 struct btf; struct btf_member; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 28b02dc67a2a..2c1f8069f7b7 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7584,6 +7584,11 @@ static int check_kfunc_call(struct bpf_verifier_env = *env, struct bpf_insn *insn, func_name); return -EACCES; } + if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) { + verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\= n"); + return -EACCES; + } + acq =3D *kfunc_flags & KF_ACQUIRE; =20 /* Check the arguments */ --=20 2.37.1