From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C251FC2B9F4 for ; Mon, 14 Jun 2021 11:21:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A567560FF1 for ; Mon, 14 Jun 2021 11:21:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232896AbhFNLXF (ORCPT ); Mon, 14 Jun 2021 07:23:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:42902 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235593AbhFNLKv (ORCPT ); Mon, 14 Jun 2021 07:10:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 66DC26134F; Mon, 14 Jun 2021 10:47:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623667628; bh=Q++CsxtREIC8FCY/1uPJKTt2EsZi3QGlUnJUgfmLe+o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8WLJf2z45vjlRc6wEMq68Xf2JnF0mKY64nS0XluCI7jM7yuy0IgL1Ns5GEoKYnRP bL8IRyRkrAiNiFcDOnbBzAkDa2k0v1amRrUKQlbjHsfFHy4JcNqL6bj/IHA7bTibeX BebpuqijOHX7xQwBoLeVxOjyPO+lzF2tC06TqDE4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexei Starovoitov , Jiri Olsa , Sasha Levin Subject: [PATCH 5.12 013/173] bpf: Add deny list of btf ids check for tracing programs Date: Mon, 14 Jun 2021 12:25:45 +0200 Message-Id: <20210614102658.593168410@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210614102658.137943264@linuxfoundation.org> References: <20210614102658.137943264@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa [ Upstream commit 35e3815fa8102fab4dee75f3547472c66581125d ] The recursion check in __bpf_prog_enter and __bpf_prog_exit leaves some (not inlined) functions unprotected: In __bpf_prog_enter: - migrate_disable is called before prog->active is checked In __bpf_prog_exit: - migrate_enable,rcu_read_unlock_strict are called after prog->active is decreased When attaching trampoline to them we get panic like: traps: PANIC: double fault, error_code: 0x0 double fault: 0000 [#1] SMP PTI RIP: 0010:__bpf_prog_enter+0x4/0x50 ... Call Trace: bpf_trampoline_6442466513_0+0x18/0x1000 migrate_disable+0x5/0x50 __bpf_prog_enter+0x9/0x50 bpf_trampoline_6442466513_0+0x18/0x1000 migrate_disable+0x5/0x50 __bpf_prog_enter+0x9/0x50 bpf_trampoline_6442466513_0+0x18/0x1000 migrate_disable+0x5/0x50 __bpf_prog_enter+0x9/0x50 bpf_trampoline_6442466513_0+0x18/0x1000 migrate_disable+0x5/0x50 ... Fixing this by adding deny list of btf ids for tracing programs and checking btf id during program verification. Adding above functions to this list. Suggested-by: Alexei Starovoitov Signed-off-by: Jiri Olsa Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210429114712.43783-1-jolsa@kernel.org Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b186d852fe3d..9e600767803b 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -12556,6 +12556,17 @@ int bpf_check_attach_target(struct bpf_verifier_log *log, return 0; } +BTF_SET_START(btf_id_deny) +BTF_ID_UNUSED +#ifdef CONFIG_SMP +BTF_ID(func, migrate_disable) +BTF_ID(func, migrate_enable) +#endif +#if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU +BTF_ID(func, rcu_read_unlock_strict) +#endif +BTF_SET_END(btf_id_deny) + static int check_attach_btf_id(struct bpf_verifier_env *env) { struct bpf_prog *prog = env->prog; @@ -12615,6 +12626,9 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) ret = bpf_lsm_verify_prog(&env->log, prog); if (ret < 0) return ret; + } else if (prog->type == BPF_PROG_TYPE_TRACING && + btf_id_set_contains(&btf_id_deny, btf_id)) { + return -EINVAL; } key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id); -- 2.30.2