From patchwork Thu Dec 14 12:50:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13493014 X-Patchwork-Delegate: paul@paul-moore.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HIfbfkFQ" Received: from mail-pl1-x62e.google.com (mail-pl1-x62e.google.com [IPv6:2607:f8b0:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2F60115; Thu, 14 Dec 2023 04:51:49 -0800 (PST) Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-1d367e7092eso5218505ad.0; Thu, 14 Dec 2023 04:51:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702558309; x=1703163109; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=TyrHpozxlKgTFPeXDtkYdtWnntKkuOFgibrMNmUzOUE=; b=HIfbfkFQeonZbdJmlwW1p7RSjAC/yIFnJB/8NuNTYcUCFHB7YfKydEjO77gFRT3GdK CQdRCz/TllrELmE5OCiENBPxJBKsMjurdilOiBW8mmISBXhyd5efgMacci3+Gye2OcTw Sl+KpVKSz/LqW3Eo5pdm6gnWOsO4WlPhMrklybdV+6mPkTvIDZGvehydJ6i4TaJar7AS xcBctylZqoKYRnNr9MW9UGeIT5nGIuXa0dN8OxoHIsMrYyG8PTeuAOHlvIpsAYcOGZou RtdY3s55JN7AUp64jmkncjRuk973PGEBi/rECw6GHQ8QKm/MBlwKttCKEzGW9t2MuTy7 2JOw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702558309; x=1703163109; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TyrHpozxlKgTFPeXDtkYdtWnntKkuOFgibrMNmUzOUE=; b=mn6yAvztEZP5OSpf0ZVv4YG24oD5JB0fXTgmZEgIljg8dMVDrqqQHHlMM+PIKNYLBQ PXUOAgJ6eFTPzv2ca1mUq6YBq/vpbnZsrOQBWqjw3HmwmxqudoAefA70vGJRm83eDA/4 LgPLGfiOuISYcB82sTu3xucivGkjWMwNRWZOSch6/UkrX+bFCj3GaqTdlzkpkYYgMnCD uHcSN2bRV5nu2H9SUgtE4vpZvi8ldLAtK3ePn179RkUrI/JW2zfD0qhdg5ZtNxbeu9To z5F23Bd8fBJMHfVc9QIsChYDC0ILCCrQNCH8WvIi7GDvloGBwnJyhwcwJNldL73Iu5c3 bMhA== X-Gm-Message-State: AOJu0YwaCN17r9zsiEYX2yUsw5KiVHTE28XmCSQavg+1XA5Jf8l5/mBH eHECIRcpaS6dBIXc/s7h1Ik= X-Google-Smtp-Source: AGHT+IHKABTJfb+UE9Rl0k944YTPHTs0rNUemBBzZ7HjNhQ1RB6o1I8s72VFPWyQj+fYjdmi8hT7kw== X-Received: by 2002:a17:902:ebcd:b0:1d0:c906:f5e0 with SMTP id p13-20020a170902ebcd00b001d0c906f5e0mr11350823plg.72.1702558309099; Thu, 14 Dec 2023 04:51:49 -0800 (PST) Received: from vultr.guest ([149.28.194.201]) by smtp.gmail.com with ESMTPSA id jj17-20020a170903049100b001d36b2e3dddsm1184528plb.192.2023.12.14.04.51.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 04:51:48 -0800 (PST) From: Yafang Shao To: akpm@linux-foundation.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, omosnace@redhat.com, casey@schaufler-ca.com, kpsingh@kernel.org, mhocko@suse.com, ying.huang@intel.com Cc: linux-mm@kvack.org, linux-security-module@vger.kernel.org, bpf@vger.kernel.org, ligang.bdlg@bytedance.com, Yafang Shao Subject: [PATCH v5 bpf-next 5/5] selftests/bpf: Add selftests for set_mempolicy with a lsm prog Date: Thu, 14 Dec 2023 12:50:33 +0000 Message-Id: <20231214125033.4158-6-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20231214125033.4158-1-laoar.shao@gmail.com> References: <20231214125033.4158-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In the straightforward LSM prog, it denies the use of mbind(2) with the mode MPOL_BIND and permits other modes. Consequently: - Absent the LSM prog, mbind(2) should invariably succeed regardless of the mode #263/1 set_mempolicy/MPOL_BIND_without_lsm:OK #263/2 set_mempolicy/MPOL_DEFAULT_without_lsm:OK - With the LSM prog - mbind(2) with the mode MPOL_BIND should result in failure #263/3 set_mempolicy/MPOL_BIND_with_lsm:OK - mbind(2) with the mode MPOL_DEFAULT should succeed #263/4 set_mempolicy/MPOL_DEFAULT_with_lsm:OK - Summary #263 set_mempolicy:OK Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yafang Shao --- .../selftests/bpf/prog_tests/set_mempolicy.c | 84 ++++++++++++++++++++++ .../selftests/bpf/progs/test_set_mempolicy.c | 28 ++++++++ 2 files changed, 112 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/set_mempolicy.c create mode 100644 tools/testing/selftests/bpf/progs/test_set_mempolicy.c diff --git a/tools/testing/selftests/bpf/prog_tests/set_mempolicy.c b/tools/testing/selftests/bpf/prog_tests/set_mempolicy.c new file mode 100644 index 0000000..4d3fe1d --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/set_mempolicy.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023 Yafang Shao */ + +#include +#include +#include +#include +#include +#include "test_set_mempolicy.skel.h" + +#define SIZE 4096 + +static void mempolicy_bind(bool success) +{ + unsigned long mask = 1; + char *addr; + int err; + + addr = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); + if (!ASSERT_OK_PTR(addr, "mmap")) + return; + + /* -lnuma is required by mbind(2), so use __NR_mbind to avoid the dependency. */ + err = syscall(__NR_mbind, addr, SIZE, MPOL_BIND, &mask, sizeof(mask), 0); + if (success) + ASSERT_OK(err, "mbind_success"); + else + ASSERT_ERR(err, "mbind_fail"); + + munmap(addr, SIZE); +} + +static void mempolicy_default(void) +{ + char *addr; + int err; + + addr = mmap(NULL, SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); + if (!ASSERT_OK_PTR(addr, "mmap")) + return; + + err = syscall(__NR_mbind, addr, SIZE, MPOL_DEFAULT, NULL, 0, 0); + ASSERT_OK(err, "mbind_success"); + + munmap(addr, SIZE); +} + +void test_set_mempolicy(void) +{ + struct test_set_mempolicy *skel; + int err; + + skel = test_set_mempolicy__open(); + if (!ASSERT_OK_PTR(skel, "open")) + return; + + skel->bss->target_pid = getpid(); + + err = test_set_mempolicy__load(skel); + if (!ASSERT_OK(err, "load")) + goto destroy; + + /* Without LSM, mbind(2) should succeed regardless of the mode. */ + if (test__start_subtest("MPOL_BIND_without_lsm")) + mempolicy_bind(true); + if (test__start_subtest("MPOL_DEFAULT_without_lsm")) + mempolicy_default(); + + /* Attach LSM prog, in which it will deny MPOL_BIND */ + err = test_set_mempolicy__attach(skel); + if (!ASSERT_OK(err, "attach")) + goto destroy; + + /* MPOL_BIND should fail. */ + if (test__start_subtest("MPOL_BIND_with_lsm")) + mempolicy_bind(false); + + /* MPOL_DEFAULT should succeed. */ + if (test__start_subtest("MPOL_DEFAULT_with_lsm")) + mempolicy_default(); + +destroy: + test_set_mempolicy__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_set_mempolicy.c b/tools/testing/selftests/bpf/progs/test_set_mempolicy.c new file mode 100644 index 0000000..b5356d5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_set_mempolicy.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 2023 Yafang Shao */ + +#include "vmlinux.h" +#include +#include + +int target_pid; + +static int mem_policy_adjustment(u64 mode) +{ + struct task_struct *task = bpf_get_current_task_btf(); + + if (task->pid != target_pid) + return 0; + + if (mode != MPOL_BIND) + return 0; + return -1; +} + +SEC("lsm/set_mempolicy") +int BPF_PROG(setmempolicy, u64 mode, u16 mode_flags, nodemask_t *nmask, u32 flags) +{ + return mem_policy_adjustment(mode); +} + +char _license[] SEC("license") = "GPL";