From patchwork Tue Jul 28 13:01:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thi=C3=A9baud_Weksteen?= X-Patchwork-Id: 11689113 X-Patchwork-Delegate: paul@paul-moore.com Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6C5D2912 for ; Tue, 28 Jul 2020 13:01:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 540E7206D8 for ; Tue, 28 Jul 2020 13:01:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nPqbrV7D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729906AbgG1NBl (ORCPT ); Tue, 28 Jul 2020 09:01:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729887AbgG1NBl (ORCPT ); Tue, 28 Jul 2020 09:01:41 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFE2AC0619D2 for ; Tue, 28 Jul 2020 06:01:40 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id o8so1927495ybg.16 for ; Tue, 28 Jul 2020 06:01:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=Ya+X644CIpKsu+82u267rP7HaSbeBJBhbsTwGl4hFHQ=; b=nPqbrV7DC1dyJE0ydgyu3pBUTlTM1knV1rD2zKoyI4ZFEgp/qomKbc4jkGR/xU0D2k AGUi8yp+/M17ScdyzCfZixdlXUJhE3sCyoRmBOch35bQsSMeSQOfZGUQQ8Ucu6Kj5bvp +GdYhMAefN2C61kWnH9HF6PfesS0k63dlm/VQ2ua+Nikh2KkGjpv7Rqp29SX3QRnHpEE zbhNjMaffKv6/RJ/McYzQr9ZjylEnE2SzBjYyidi9UmF7DOLJCYMaTwJDSXffoLCN/qp j4db66drGJlDAw/P5AvAt0PsKz20Uj6s/zNlXPJ0212XbVlaLSgBxT5RjIO4evss2+qB j7jQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=Ya+X644CIpKsu+82u267rP7HaSbeBJBhbsTwGl4hFHQ=; b=qRO9UoXaiu4GEP9QiCU+y501K+L5OzRB3PUhsPD9prcFTvk9CKkPdjiWwzt1HFIWxG Tvlm2nWVYFHAYpawyXP+1gn2EnbnrM75Mf7XU97FyJo2+ozECGzpkHHXUWAUwSYczaFZ GRqLppCgKY7txJInsuWQGgcNnellu4PgMSpLYKAu2rmwRsZNiBI56VIaR+WWWrUOIWOE 7wwa5kZUfr0kCKd2EzhM+PxQaSxV+KULePifRcKMfIqtyj1NP+fsZ7dQRIf7Hm3vf/VZ jo2dRQ9J60uwXIbv/DGKzEf/BMuXCXlOqVhK8BhaEpaKwD4J9WxJuOuSLDrqM9ezUrrW EGmA== X-Gm-Message-State: AOAM531NulTq/3uCWRSRXukgmRhiU+ClWrEnc6/1dMgCSL20BCofBMdC aIILblSIPn8ZIHtGyKxX2nDIhR/jCg== X-Google-Smtp-Source: ABdhPJy4hzucmW0xAq9k3SvB7xnSJEQ4n7JtK2bmteR8LMMvdZaP74tgxJV1oY1S3YTTAhoeu/jMAo8mlQ== X-Received: by 2002:a05:6902:512:: with SMTP id x18mr13070478ybs.496.1595941300068; Tue, 28 Jul 2020 06:01:40 -0700 (PDT) Date: Tue, 28 Jul 2020 15:01:04 +0200 Message-Id: <20200728130120.3633360-1-tweek@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.28.0.rc0.142.g3c755180ce-goog Subject: [PATCH v2] selinux: add tracepoint on denials From: " =?utf-8?q?Thi=C3=A9baud_Weksteen?= " To: Paul Moore Cc: Nick Kralevich , " =?utf-8?q?Thi=C3=A9baud_Weksteen?= " , Joel Fernandes , Stephen Smalley , Eric Paris , Steven Rostedt , Ingo Molnar , Mauro Carvalho Chehab , "David S. Miller" , Rob Herring , linux-kernel@vger.kernel.org, selinux@vger.kernel.org Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org The audit data currently captures which process and which target is responsible for a denial. There is no data on where exactly in the process that call occurred. Debugging can be made easier by being able to reconstruct the unified kernel and userland stack traces [1]. Add a tracepoint on the SELinux denials which can then be used by userland (i.e. perf). Although this patch could manually be added by each OS developer to trouble shoot a denial, adding it to the kernel streamlines the developers workflow. [1] https://source.android.com/devices/tech/debug/native_stack_dump Signed-off-by: Thiébaud Weksteen Signed-off-by: Joel Fernandes --- Changes in v2: - Replace %d formatter with %x - Replace TRACE_EVENT with TRACE_EVENT_CONDITION - Add pid to structure and printk - Rename structure fields for clarity MAINTAINERS | 1 + include/trace/events/selinux.h | 39 ++++++++++++++++++++++++++++++++++ security/selinux/avc.c | 5 +++++ 3 files changed, 45 insertions(+) create mode 100644 include/trace/events/selinux.h diff --git a/MAINTAINERS b/MAINTAINERS index f0569cf304ca..0f74c8f073ab 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15369,6 +15369,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux.git F: Documentation/ABI/obsolete/sysfs-selinux-checkreqprot F: Documentation/ABI/obsolete/sysfs-selinux-disable F: Documentation/admin-guide/LSM/SELinux.rst +F: include/trace/events/selinux.h F: include/uapi/linux/selinux_netlink.h F: scripts/selinux/ F: security/selinux/ diff --git a/include/trace/events/selinux.h b/include/trace/events/selinux.h new file mode 100644 index 000000000000..287e1ecb4451 --- /dev/null +++ b/include/trace/events/selinux.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM selinux + +#if !defined(_TRACE_SELINUX_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_SELINUX_H + +#include + +TRACE_EVENT_CONDITION(selinux_denied, + + TP_PROTO(struct selinux_audit_data *sad, pid_t pid), + + TP_ARGS(sad, pid), + + TP_CONDITION(sad->denied), + + TP_STRUCT__entry( + __field(pid_t, pid) + __field(int, tclass) + __field(int, audited) + ), + + TP_fast_assign( + __entry->pid = pid; + __entry->tclass = sad->tclass; + __entry->audited = sad->audited; + ), + + TP_printk("denied pid=%d tclass=%x audited=%x", + __entry->pid, + __entry->tclass, + __entry->audited) +); + +#endif + +/* This part must be outside protection */ +#include diff --git a/security/selinux/avc.c b/security/selinux/avc.c index d18cb32a242a..ca8206f38d8a 100644 --- a/security/selinux/avc.c +++ b/security/selinux/avc.c @@ -31,6 +31,9 @@ #include "avc_ss.h" #include "classmap.h" +#define CREATE_TRACE_POINTS +#include + #define AVC_CACHE_SLOTS 512 #define AVC_DEF_CACHE_THRESHOLD 512 #define AVC_CACHE_RECLAIM 16 @@ -665,6 +668,8 @@ static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) const char **perms; int i, perm; + trace_selinux_denied(sad, task_tgid_nr(current)); + audit_log_format(ab, "avc: %s ", sad->denied ? "denied" : "granted"); if (av == 0) {