From patchwork Tue Jul 9 00:51:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Liao, Chang" X-Patchwork-Id: 13727152 X-Patchwork-Delegate: bpf@iogearbox.net Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BB84924B4A; Tue, 9 Jul 2024 01:00:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720486814; cv=none; b=ZIYyVTlw2zxTxrXr6BXN5pjPcQUuW6MZL8N5rFyXLPWRtj6qaZUwz/UgZuIY3NqTFQOMcHBT+4GXuhWTCGRi6dUFcYPiOh7OjQuVP7V9F8XIdGxjBooBtweTj7evIZmqGVv+OoMn0N6xxeLRV2J9yqd7JI3eLv7BQIyMgT+P7C8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720486814; c=relaxed/simple; bh=f8u+3jaw5EtE3CvyeAy6cdqI83Y22LA9WRWr9WpaZis=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CA2L/oodORMgUKlyd1rq6VrBn5ZxwVtWMIoHxvDOyNbjUqj9CrHu6HSJUyEZv3f0pleIKZgJ8iX4GEc6IUnSRr+8r8K/TOpH6z1riNr2X08xwahXjNOD3MPmgebpkQ9sAebKsyqeiKjBQKzJ1Zpw5K5Ct6Re4WJU8ujKYxxLqVA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.194]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4WJ2bM4G4yz1T5q7; Tue, 9 Jul 2024 08:55:27 +0800 (CST) Received: from kwepemd200013.china.huawei.com (unknown [7.221.188.133]) by mail.maildlp.com (Postfix) with ESMTPS id 4173F1402E1; Tue, 9 Jul 2024 09:00:08 +0800 (CST) Received: from huawei.com (10.67.174.28) by kwepemd200013.china.huawei.com (7.221.188.133) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Tue, 9 Jul 2024 09:00:07 +0800 From: Liao Chang To: , , , , , , , , , , , , , , , , , , , , , , , CC: , , , Subject: [PATCH 2/2] selftests/bpf: Add uretprobe test for return_instance management Date: Tue, 9 Jul 2024 00:51:42 +0000 Message-ID: <20240709005142.4044530-3-liaochang1@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240709005142.4044530-1-liaochang1@huawei.com> References: <20240709005142.4044530-1-liaochang1@huawei.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemd200013.china.huawei.com (7.221.188.133) X-Patchwork-Delegate: bpf@iogearbox.net This patch add three testcases to verify the proper management of return_instance data by uretprobes: - uretprobe_longjmp() verifies that longjmp() bypasses the uretprobe BPF program attached to the exit of instrumented function. - uretprobe_cleanup_return_instance() verifies that uretprobe reclaim the return_instances data created before a longjmp(), which leads to kernel recount the nested depth of instrumented function. - uretprobe_reach_nestedness_limit() confirms that the uretprobe doesn't reclaim the return_instances data created before longjmp() and hijack the return address of instrumented function upon the nestedness depth reache the limits (64). Signed-off-by: Liao Chang --- .../bpf/prog_tests/uretprobe_depth.c | 150 ++++++++++++++++++ .../selftests/bpf/progs/uretprobe_depth.c | 19 +++ 2 files changed, 169 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/uretprobe_depth.c create mode 100644 tools/testing/selftests/bpf/progs/uretprobe_depth.c diff --git a/tools/testing/selftests/bpf/prog_tests/uretprobe_depth.c b/tools/testing/selftests/bpf/prog_tests/uretprobe_depth.c new file mode 100644 index 000000000000..ba03b1868e37 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/uretprobe_depth.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +#include +#include +#include +#include +#include +#include "uretprobe_depth.skel.h" + +#define RETVAL 0xFFFF +#define JMPVAL 0x4B1D +#define MAX_URETPROBE_DEPTH 64 // See include/linux/uprobes.h +#define NR_OMITTED_URETPROBE 16 +static jmp_buf jmp; + +unsigned long __uretprobe_longjmp(int nest, int jmpval, int retval) +{ + if (nest) { + nest = ++retval < MAX_URETPROBE_DEPTH + NR_OMITTED_URETPROBE; + return __uretprobe_longjmp(nest, jmpval, retval); + } + + if (jmpval == JMPVAL) { + longjmp(jmp, jmpval); + return 0; + } else + return retval; +} + +static void uretprobe_longjmp(void) +{ + if (setjmp(jmp) == JMPVAL) { + __uretprobe_longjmp(0, 0, JMPVAL); + return; + } + + __uretprobe_longjmp(0, JMPVAL, RETVAL); +} + +static void uretprobe_cleanup_return_instances(void) +{ + if (setjmp(jmp) == JMPVAL) { + /* + * Cleanup these return instance data created before longjmp + * firstly. Then create 16 new return_instance data from here. + */ + __uretprobe_longjmp(1, 0, MAX_URETPROBE_DEPTH); + return; + } + + /* Create 8 return_instance data from here. */ + __uretprobe_longjmp(1, JMPVAL, + MAX_URETPROBE_DEPTH + NR_OMITTED_URETPROBE / 2); +} + +static void uretprobe_reach_nestedness_limit(void) +{ + if (setjmp(jmp) == JMPVAL) { + /* + * Due to uretprobe reach to the nestedness limit, it doesn't + * cleanup the return instance created before longjmp. + */ + __uretprobe_longjmp(1, 0, MAX_URETPROBE_DEPTH); + return; + } + + /* Create 64 return_instance from here. */ + __uretprobe_longjmp(1, JMPVAL, 0); +} + +static void test_uretprobe_longjmp(void) +{ + struct uretprobe_depth *skel = NULL; + int err; + + skel = uretprobe_depth__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uretprobe_depth__open_and_load")) + goto cleanup; + + err = uretprobe_depth__attach(skel); + if (!ASSERT_OK(err, "uretprobe_depth__attach")) + goto cleanup; + + skel->bss->retval = -1; + + uretprobe_longjmp(); + + ASSERT_EQ(skel->bss->retval, JMPVAL, "return value"); + +cleanup: + uretprobe_depth__destroy(skel); +} + +static void test_uretprobe_reach_nestedness_limit(void) +{ + struct uretprobe_depth *skel = NULL; + int err; + + skel = uretprobe_depth__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uretprobe_depth__open_and_load")) + goto cleanup; + + err = uretprobe_depth__attach(skel); + if (!ASSERT_OK(err, "uretprobe_depth__attach")) + goto cleanup; + + skel->bss->depth = 0; + + uretprobe_reach_nestedness_limit(); + + ASSERT_EQ(skel->bss->depth, 0, "nest depth"); + +cleanup: + uretprobe_depth__destroy(skel); +} + +static void test_uretprobe_cleanup_return_instances(void) +{ + struct uretprobe_depth *skel = NULL; + int err; + + skel = uretprobe_depth__open_and_load(); + if (!ASSERT_OK_PTR(skel, "uretprobe_depth__open_and_load")) + goto cleanup; + + err = uretprobe_depth__attach(skel); + if (!ASSERT_OK(err, "uretprobe_depth__attach")) + goto cleanup; + + skel->bss->depth = 0; + + uretprobe_cleanup_return_instances(); + + ASSERT_EQ(skel->bss->depth, NR_OMITTED_URETPROBE + 1, "nest depth"); + +cleanup: + uretprobe_depth__destroy(skel); +} + +void test_uretprobe_return_instance(void) +{ + if (test__start_subtest("uretprobe_longjmp")) + test_uretprobe_longjmp(); + if (test__start_subtest("uretprobe_cleanup_return_instances")) + test_uretprobe_cleanup_return_instances(); + if (test__start_subtest("uretprobe_reach_nestedness_limit")) + test_uretprobe_reach_nestedness_limit(); +} diff --git a/tools/testing/selftests/bpf/progs/uretprobe_depth.c b/tools/testing/selftests/bpf/progs/uretprobe_depth.c new file mode 100644 index 000000000000..b71f2de52b5e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/uretprobe_depth.c @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "vmlinux.h" +#include +#include + +int depth; +unsigned long retval; + +char _license[] SEC("license") = "GPL"; + +SEC("uretprobe//proc/self/exe:__uretprobe_longjmp") +int uretprobe(struct pt_regs *ctx) +{ + depth++; +#if defined(__TARGET_ARCH_arm64) || defined(__aarch64__) + retval = ctx->regs[0]; +#endif + return 0; +}