From patchwork Wed Jan 15 17:13:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 11335455 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 A416792A for ; Wed, 15 Jan 2020 17:13:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 788B524685 for ; Wed, 15 Jan 2020 17:13:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="VoK/cfOe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728993AbgAORNd (ORCPT ); Wed, 15 Jan 2020 12:13:33 -0500 Received: from mail-wm1-f66.google.com ([209.85.128.66]:36841 "EHLO mail-wm1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729238AbgAORNd (ORCPT ); Wed, 15 Jan 2020 12:13:33 -0500 Received: by mail-wm1-f66.google.com with SMTP id p17so769177wma.1 for ; Wed, 15 Jan 2020 09:13:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Lk48qetZKyKWukIhgwRh7oanEwAxdHUHawT8EKhLs24=; b=VoK/cfOe18OMZeAhDw6GvIcgIn+YfEmL6obJDGmidtIeyWIry3wPOk4NCkSghYOqgt FeSzZ7cht3VGP5OcZA27IdhxA1nLZrCn47WOd4vn8st/5s/ELgE31T77Hh95XdCiVWTq +WTpsm9K1VCH6FCQ9+xRFEFX/AGr4ShHKjHKk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Lk48qetZKyKWukIhgwRh7oanEwAxdHUHawT8EKhLs24=; b=XhpmzPRZ+aU3+DIvXQYCBsX3Z9MiRaYqetnR6BCFEwm13Iqv0XcYUsYyYdm37Awaka y+2ujpfafDyCdGGtTPUhSPCD2hx4rQMYG+5yL9fU/k652zELos15Gk7Os6NtTIwQtK0I JVRtSQZy3tiH6W8O5Ut+MJGdO3ulUCrVQeSmc4a2NOAIGuxKZ2SveWS/Ad29hbFe3mUN 6ZewNUAX4rPDgNHP2HK7AdjiNUp9VhcYxIIbc9OgIs37/Y0nR7KvtTL2GtS7EclARdzC sXlhAuT1dtmHzKMAsMWG1JYZOnFdgLYGDCWYwP5WkZgWqTKgb/OHJ26h9DTy49h1rzWb Vxvw== X-Gm-Message-State: APjAAAXVvEW/RjpcyJ5orpCJn5f2hKV2Tn9Wiq3spLZm0FwmzC3u5gdP HJcp9OH+dwGfMlphQRwNidCI6Q== X-Google-Smtp-Source: APXvYqxZnUBXj2TFr0fRlMTriJRJqkxc4KcmmCaQtMroHNbH2lkUynRPDo66FDJDeFTfsoDchvsRXw== X-Received: by 2002:a05:600c:2c2:: with SMTP id 2mr879104wmn.155.1579108411281; Wed, 15 Jan 2020 09:13:31 -0800 (PST) Received: from kpsingh-kernel.localdomain ([2620:0:105f:fd00:84f3:4331:4ae9:c5f1]) by smtp.gmail.com with ESMTPSA id d16sm26943227wrg.27.2020.01.15.09.13.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jan 2020 09:13:30 -0800 (PST) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Brendan Jackman , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [PATCH bpf-next v2 09/10] bpf: lsm: Add selftests for BPF_PROG_TYPE_LSM Date: Wed, 15 Jan 2020 18:13:32 +0100 Message-Id: <20200115171333.28811-10-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200115171333.28811-1-kpsingh@chromium.org> References: <20200115171333.28811-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh * Load a BPF program that audits mprotect calls * Attach the program to the "file_mprotect" LSM hook * Initialize the perf events buffer and poll for audit events * Do an mprotect on some memory allocated on the heap * Verify if the audit event was received Signed-off-by: KP Singh --- MAINTAINERS | 2 + tools/testing/selftests/bpf/lsm_helpers.h | 19 ++++++ .../bpf/prog_tests/lsm_mprotect_audit.c | 58 +++++++++++++++++++ .../selftests/bpf/progs/lsm_mprotect_audit.c | 48 +++++++++++++++ 4 files changed, 127 insertions(+) create mode 100644 tools/testing/selftests/bpf/lsm_helpers.h create mode 100644 tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c create mode 100644 tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c diff --git a/MAINTAINERS b/MAINTAINERS index 02d7e05e9b75..5d553c2e7452 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -3210,6 +3210,8 @@ L: bpf@vger.kernel.org S: Maintained F: security/bpf/ F: include/linux/bpf_lsm.h +F: tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c +F: tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c BROADCOM B44 10/100 ETHERNET DRIVER M: Michael Chan diff --git a/tools/testing/selftests/bpf/lsm_helpers.h b/tools/testing/selftests/bpf/lsm_helpers.h new file mode 100644 index 000000000000..8bad08f77654 --- /dev/null +++ b/tools/testing/selftests/bpf/lsm_helpers.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright 2019 Google LLC. + */ +#ifndef _LSM_HELPERS_H +#define _LSM_HELPERS_H + +struct lsm_mprotect_audit_result { + /* This ensures that the LSM Hook only monitors the PID requested + * by the loader + */ + __u32 monitored_pid; + /* The number of mprotect calls for the monitored PID. + */ + __u32 mprotect_count; +}; + +#endif /* _LSM_HELPERS_H */ diff --git a/tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c b/tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c new file mode 100644 index 000000000000..ff90b874eafc --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/lsm_mprotect_audit.c @@ -0,0 +1,58 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2019 Google LLC. + */ + +#include +#include +#include +#include +#include "lsm_helpers.h" +#include "lsm_mprotect_audit.skel.h" + +int heap_mprotect(void) +{ + void *buf; + long sz; + + sz = sysconf(_SC_PAGESIZE); + if (sz < 0) + return sz; + + buf = memalign(sz, 2 * sz); + if (buf == NULL) + return -ENOMEM; + + return mprotect(buf, sz, PROT_READ | PROT_EXEC); +} + +void test_lsm_mprotect_audit(void) +{ + struct lsm_mprotect_audit_result *result; + struct lsm_mprotect_audit *skel = NULL; + int err, duration = 0; + + skel = lsm_mprotect_audit__open_and_load(); + if (CHECK(!skel, "skel_load", "lsm_mprotect_audit skeleton failed\n")) + goto close_prog; + + err = lsm_mprotect_audit__attach(skel); + if (CHECK(err, "attach", "lsm_mprotect_audit attach failed: %d\n", err)) + goto close_prog; + + result = &skel->bss->result; + result->monitored_pid = getpid(); + + err = heap_mprotect(); + if (CHECK(err < 0, "heap_mprotect", "err %d errno %d\n", err, errno)) + goto close_prog; + + /* Make sure mprotect_audit program was triggered + * and detected an mprotect on the heap. + */ + CHECK_FAIL(result->mprotect_count != 1); + +close_prog: + lsm_mprotect_audit__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c b/tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c new file mode 100644 index 000000000000..f4569b418616 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/lsm_mprotect_audit.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright 2019 Google LLC. + */ + +#include +#include +#include "bpf_helpers.h" +#include "bpf_trace_helpers.h" +#include "lsm_helpers.h" + +char _license[] SEC("license") = "GPL"; + +struct lsm_mprotect_audit_result result = { + .mprotect_count = 0, + .monitored_pid = 0, +}; + +/* + * Define some of the structs used in the BPF program. + * Only the field names and their sizes need to be the + * same as the kernel type, the order is irrelevant. + */ +struct mm_struct { + unsigned long start_brk, brk; +} __attribute__((preserve_access_index)); + +struct vm_area_struct { + unsigned long vm_start, vm_end; + struct mm_struct *vm_mm; +} __attribute__((preserve_access_index)); + +SEC("lsm/file_mprotect") +int BPF_PROG(mprotect_audit, struct vm_area_struct *vma, + unsigned long reqprot, unsigned long prot) +{ + __u32 pid = bpf_get_current_pid_tgid(); + int is_heap = 0; + + is_heap = (vma->vm_start >= vma->vm_mm->start_brk && + vma->vm_end <= vma->vm_mm->brk); + + if (is_heap && result.monitored_pid == pid) + result.mprotect_count++; + + return 0; +}