From patchwork Mon Jul 11 08:32:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Savkov X-Patchwork-Id: 12913115 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 32BD7C43334 for ; Mon, 11 Jul 2022 08:32:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230246AbiGKIcs (ORCPT ); Mon, 11 Jul 2022 04:32:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230147AbiGKIcb (ORCPT ); Mon, 11 Jul 2022 04:32:31 -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 A59DC1F630 for ; Mon, 11 Jul 2022 01:32:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657528348; 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=JjYLBUMSftH7/Ewb1QZ49Vc0Exdm+flUGINBW+1YvW0=; b=R9VXMZQZxbvx9qCcv8cwKgmPRPJCNwpOmdE/nl70gZurdtgIn6Pif/tiCnGRy1tLll8Wop o3UQnllDVLnyLD9SC1Z4gFiw6kJPyyjlm/HKGBxUT3hoSiWyljscouK+aHzIlZ7Ahi7DvD Zbmts1dy4rvXFXfbfsncqI5HhKmqxh4= 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-399-m3OBsIK6PtyXp0jhmv-5iQ-1; Mon, 11 Jul 2022 04:32:23 -0400 X-MC-Unique: m3OBsIK6PtyXp0jhmv-5iQ-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 4BCD8185A79C; Mon, 11 Jul 2022 08:32:23 +0000 (UTC) Received: from shodan.usersys.redhat.com (unknown [10.43.17.22]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 096F440CF8EA; Mon, 11 Jul 2022 08:32:22 +0000 (UTC) Received: by shodan.usersys.redhat.com (Postfix, from userid 1000) id 020A51C02A5; Mon, 11 Jul 2022 10:32:22 +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 , Artem Savkov Subject: [RFC PATCH bpf-next 3/4] bpf: add bpf_panic() helper Date: Mon, 11 Jul 2022 10:32:19 +0200 Message-Id: <20220711083220.2175036-4-asavkov@redhat.com> In-Reply-To: <20220711083220.2175036-1-asavkov@redhat.com> References: <20220711083220.2175036-1-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 X-Patchwork-State: RFC Add a helper that will make the kernel panic immediately with specified message. Using this helper requires kernel.destructive_bpf_enabled sysctl to be enabled, BPF_F_DESTRUCTIVE flag to be supplied on program load as well as CAP_SYS_BOOT capabilities. Signed-off-by: Artem Savkov --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 7 +++++++ kernel/bpf/core.c | 1 + kernel/bpf/helpers.c | 13 +++++++++++++ kernel/bpf/verifier.c | 7 +++++++ kernel/trace/bpf_trace.c | 2 ++ tools/include/uapi/linux/bpf.h | 7 +++++++ 7 files changed, 38 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 43c008e3587a..77c20ba9ca8e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2339,6 +2339,7 @@ extern const struct bpf_func_proto bpf_strtol_proto; extern const struct bpf_func_proto bpf_strtoul_proto; extern const struct bpf_func_proto bpf_tcp_sock_proto; extern const struct bpf_func_proto bpf_jiffies64_proto; +extern const struct bpf_func_proto bpf_panic_proto; extern const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto; extern const struct bpf_func_proto bpf_event_output_data_proto; extern const struct bpf_func_proto bpf_ringbuf_output_proto; diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4423874b5da4..e2e2c4de44ee 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -3927,6 +3927,12 @@ union bpf_attr { * Return * The 64 bit jiffies * + * void bpf_panic(const char *msg) + * Description + * Make the kernel panic immediately + * Return + * void + * * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags) * Description * For an eBPF program attached to a perf event, retrieve the @@ -5452,6 +5458,7 @@ union bpf_attr { FN(tcp_send_ack), \ FN(send_signal_thread), \ FN(jiffies64), \ + FN(panic), \ FN(read_branch_records), \ FN(get_ns_current_pid_tgid), \ FN(xdp_output), \ diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index b5ffebcce6cc..0f333a0e85a5 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2649,6 +2649,7 @@ const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; const struct bpf_func_proto bpf_spin_lock_proto __weak; const struct bpf_func_proto bpf_spin_unlock_proto __weak; const struct bpf_func_proto bpf_jiffies64_proto __weak; +const struct bpf_func_proto bpf_panic_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a1c84d256f83..5cb90208a264 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -374,6 +374,19 @@ const struct bpf_func_proto bpf_jiffies64_proto = { .ret_type = RET_INTEGER, }; +BPF_CALL_1(bpf_panic, const char *, msg) +{ + panic(msg); + return 0; +} + +const struct bpf_func_proto bpf_panic_proto = { + .func = bpf_panic, + .gpl_only = false, + .ret_type = RET_VOID, + .arg1_type = ARG_PTR_TO_CONST_STR, +}; + #ifdef CONFIG_CGROUPS BPF_CALL_0(bpf_get_current_cgroup_id) { diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 2859901ffbe3..f49c026917c5 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7285,6 +7285,13 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn reg_type_str(env, regs[BPF_REG_1].type)); return -EACCES; } + break; + case BPF_FUNC_panic: + struct bpf_prog_aux *aux = env->prog->aux; + if (!aux->destructive) { + verbose(env, "bpf_panic() calls require BPF_F_DESTRUCTIVE flag\n"); + return -EACCES; + } } if (err) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 4be976cf7d63..3ee888507795 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1304,6 +1304,8 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_find_vma_proto; case BPF_FUNC_trace_vprintk: return bpf_get_trace_vprintk_proto(); + case BPF_FUNC_panic: + return capable(CAP_SYS_BOOT) && destructive_ebpf_enabled() ? &bpf_panic_proto : NULL; default: return bpf_base_func_proto(func_id); } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 4423874b5da4..e2e2c4de44ee 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -3927,6 +3927,12 @@ union bpf_attr { * Return * The 64 bit jiffies * + * void bpf_panic(const char *msg) + * Description + * Make the kernel panic immediately + * Return + * void + * * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags) * Description * For an eBPF program attached to a perf event, retrieve the @@ -5452,6 +5458,7 @@ union bpf_attr { FN(tcp_send_ack), \ FN(send_signal_thread), \ FN(jiffies64), \ + FN(panic), \ FN(read_branch_records), \ FN(get_ns_current_pid_tgid), \ FN(xdp_output), \