From patchwork Wed Aug 10 06:59:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 12940277 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 E2F30C00140 for ; Wed, 10 Aug 2022 06:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbiHJG7O (ORCPT ); Wed, 10 Aug 2022 02:59:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230165AbiHJG7M (ORCPT ); Wed, 10 Aug 2022 02:59:12 -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 CBEF872EC3 for ; Tue, 9 Aug 2022 23:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660114750; 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=LvZxvP/+kyLscaE/F02YPn8zWMT2bT669Jr4yYn/GnRfMGYIXGEzbBLjV0AQrbL8kVEOiK Yq0MVUHoCK3T26hWm9Yte+LfwKFuqqYSsN4O/zeWyT+RbcmCQC2+wVMk4+z6o4KdHrFACJ x0e8HyTXxuUVes9dtiraanJ8jUOox2E= 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 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net 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 only be called by sleepable BPF programs (BPF_F_SLEEPABLE). +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 can be +added later. + 2.5 Registering the kfuncs -------------------------- 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 arguments */ -#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 */ 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 = *kfunc_flags & KF_ACQUIRE; /* Check the arguments */ From patchwork Wed Aug 10 06:59:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 12940280 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 12F49C25B0C for ; Wed, 10 Aug 2022 06:59:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231418AbiHJG7S (ORCPT ); Wed, 10 Aug 2022 02:59:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229636AbiHJG7O (ORCPT ); Wed, 10 Aug 2022 02:59:14 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7DD2D72EC2 for ; Tue, 9 Aug 2022 23:59:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660114751; 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=TuXxip5m/+uaodvEMxILggFHmrvIlLjtGXFaewxf3tM=; b=ZDX8PeEKYSeqiuRtPq2TP3C05uLNioY6nwmS1pwQFuTnLPgFPn09w2so18ZHcMMpUb9UnK TiWQYUm3EgHh2YIUy+CvpNEjagPee0nDqYlpVH5Vw9K0BLg0k2J/i2RYfziyBGn3PNnwOL WJ5TvUqVisg+qdzEOctR2rutxcsp69Q= 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-412-WF0i6ggTMUClpl2sSH7BCg-1; Wed, 10 Aug 2022 02:59:08 -0400 X-MC-Unique: WF0i6ggTMUClpl2sSH7BCg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 26C7F299E76B; 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 D6E9440CF8EB; Wed, 10 Aug 2022 06:59:07 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id E1CAF1C02AD; 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 2/3] bpf: export crash_kexec() as destructive kfunc Date: Wed, 10 Aug 2022 08:59:04 +0200 Message-Id: <20220810065905.475418-3-asavkov@redhat.com> In-Reply-To: <20220810065905.475418-1-asavkov@redhat.com> References: <20220810065905.475418-1-asavkov@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Allow properly marked bpf programs to call crash_kexec(). Signed-off-by: Artem Savkov --- kernel/bpf/helpers.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a95eb9fb01ff..3c1b9bbcf971 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1725,3 +1725,21 @@ bpf_base_func_proto(enum bpf_func_id func_id) return NULL; } } + +BTF_SET8_START(tracing_btf_ids) +#ifdef CONFIG_KEXEC_CORE +BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE) +#endif +BTF_SET8_END(tracing_btf_ids) + +static const struct btf_kfunc_id_set tracing_kfunc_set = { + .owner = THIS_MODULE, + .set = &tracing_btf_ids, +}; + +static int __init kfunc_init(void) +{ + return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set); +} + +late_initcall(kfunc_init); From patchwork Wed Aug 10 06:59:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 12940278 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 0253DC25B08 for ; Wed, 10 Aug 2022 06:59:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbiHJG7N (ORCPT ); Wed, 10 Aug 2022 02:59:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229951AbiHJG7M (ORCPT ); Wed, 10 Aug 2022 02:59:12 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 20C1E72EC2 for ; Tue, 9 Aug 2022 23:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660114750; 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=t3awSX3Tq4QpWeUfA1tbizxgPGHJw6AQeDWWE3eaTyI=; b=BRUQK1uQmTT8kVp/SzgOvbHiAYvhsXMeym6tAZskjIHu8gVcorILjaRsBnNMvlIZhUbQeu UzxWO+IaJB5s3DqscDQuh2XtGkrp2sr8tOkKWZ00aM+LDwakMGAoPuLj8d/zirvWxRks5E YnkL1G2Qz8MZ6ua1RUj1ocPEgtTrPlg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-312-D8Vbd_zvO-qCq1gk_85QFw-1; Wed, 10 Aug 2022 02:59:08 -0400 X-MC-Unique: D8Vbd_zvO-qCq1gk_85QFw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 242161019C95; 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 D6D0C145BA44; Wed, 10 Aug 2022 06:59:07 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id E60741C0461; 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 3/3] selftests/bpf: add destructive kfunc test Date: Wed, 10 Aug 2022 08:59:05 +0200 Message-Id: <20220810065905.475418-4-asavkov@redhat.com> In-Reply-To: <20220810065905.475418-1-asavkov@redhat.com> References: <20220810065905.475418-1-asavkov@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add a test checking that programs calling destructive kfuncs can only do so if they have CAP_SYS_BOOT capabilities. Signed-off-by: Artem Savkov --- net/bpf/test_run.c | 5 +++ .../selftests/bpf/prog_tests/kfunc_call.c | 36 +++++++++++++++++++ .../bpf/progs/kfunc_call_destructive.c | 14 ++++++++ 3 files changed, 55 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_destructive.c diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index cbc9cd5058cb..afa7125252f6 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -695,6 +695,10 @@ noinline void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) { } +noinline void bpf_kfunc_call_test_destructive(void) +{ +} + __diag_pop(); ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO); @@ -719,6 +723,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2) BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE) BTF_SET8_END(test_sk_check_kfunc_ids) static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size, diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index c00eb974eb85..351fafa006fb 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -5,6 +5,9 @@ #include "kfunc_call_test.lskel.h" #include "kfunc_call_test_subprog.skel.h" #include "kfunc_call_test_subprog.lskel.h" +#include "kfunc_call_destructive.skel.h" + +#include "cap_helpers.h" static void test_main(void) { @@ -86,6 +89,36 @@ static void test_subprog_lskel(void) kfunc_call_test_subprog_lskel__destroy(skel); } +static int test_destructive_open_and_load(void) +{ + struct kfunc_call_destructive *skel; + int err; + + skel = kfunc_call_destructive__open(); + if (!ASSERT_OK_PTR(skel, "prog_open")) + return -1; + + err = kfunc_call_destructive__load(skel); + + kfunc_call_destructive__destroy(skel); + + return err; +} + +static void test_destructive(void) +{ + __u64 save_caps = 0; + + ASSERT_OK(test_destructive_open_and_load(), "succesful_load"); + + if (!ASSERT_OK(cap_disable_effective(1ULL << CAP_SYS_BOOT, &save_caps), "drop_caps")) + return; + + ASSERT_EQ(test_destructive_open_and_load(), -13, "no_caps_failure"); + + cap_enable_effective(save_caps, NULL); +} + void test_kfunc_call(void) { if (test__start_subtest("main")) @@ -96,4 +129,7 @@ void test_kfunc_call(void) if (test__start_subtest("subprog_lskel")) test_subprog_lskel(); + + if (test__start_subtest("destructive")) + test_destructive(); } diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c new file mode 100644 index 000000000000..767472bc5a97 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kfunc_call_destructive.c @@ -0,0 +1,14 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +extern void bpf_kfunc_call_test_destructive(void) __ksym; + +SEC("tc") +int kfunc_destructive_test(void) +{ + bpf_kfunc_call_test_destructive(); + return 0; +} + +char _license[] SEC("license") = "GPL";