| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20211027220043.1937648-3-songliubraving@fb.com>
Date: Wed, 27 Oct 2021 15:00:43 -0700
From: Song Liu <songliubraving@...com>
To: <bpf@...r.kernel.org>, <netdev@...r.kernel.org>
CC: <ast@...nel.org>, <daniel@...earbox.net>, <andrii@...nel.org>,
<kernel-team@...com>, <kpsingh@...nel.org>,
Song Liu <songliubraving@...com>
Subject: [PATCH bpf-next 2/2] selftests/bpf: add tests for bpf_find_vma
Add tests for bpf_find_vma in perf_event program and kprobe program. The
perf_event program is triggered from NMI context, so the second call of
bpf_find_vma() will return -EBUSY (irq_work busy). The kprobe program,
on the other hand, does not have this constraint.
Signed-off-by: Song Liu <songliubraving@...com>
---
.../selftests/bpf/prog_tests/find_vma.c | 95 +++++++++++++++++++
tools/testing/selftests/bpf/progs/find_vma.c | 70 ++++++++++++++
2 files changed, 165 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/find_vma.c
create mode 100644 tools/testing/selftests/bpf/progs/find_vma.c
diff --git a/tools/testing/selftests/bpf/prog_tests/find_vma.c b/tools/testing/selftests/bpf/prog_tests/find_vma.c
new file mode 100644
index 0000000000000..34d4d02c60153
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/find_vma.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include <test_progs.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include "find_vma.skel.h"
+
+static void test_and_reset_skel(struct find_vma *skel, int expected_find_zero_ret)
+{
+ ASSERT_EQ(skel->bss->found_vm_exec, 1, "found_vm_exec");
+ ASSERT_EQ(skel->data->find_addr_ret, 0, "find_addr_ret");
+ ASSERT_EQ(skel->data->find_zero_ret, expected_find_zero_ret, "find_zero_ret");
+ ASSERT_OK_PTR(strstr(skel->bss->d_iname, "test_progs"), "find_test_progs");
+
+ skel->bss->found_vm_exec = 0;
+ skel->data->find_addr_ret = -1;
+ skel->data->find_zero_ret = -1;
+ skel->bss->d_iname[0] = 0;
+}
+
+static int open_pe(void)
+{
+ struct perf_event_attr attr = {0};
+ int pfd;
+
+ /* create perf event */
+ attr.size = sizeof(attr);
+ attr.type = PERF_TYPE_HARDWARE;
+ attr.config = PERF_COUNT_HW_CPU_CYCLES;
+ attr.freq = 1;
+ attr.sample_freq = 4000;
+ pfd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, PERF_FLAG_FD_CLOEXEC);
+
+ return pfd >= 0 ? pfd : -errno;
+}
+
+static void test_find_vma_pe(struct find_vma *skel)
+{
+ struct bpf_link *link = NULL;
+ volatile int j = 0;
+ int pfd = -1, i;
+
+ pfd = open_pe();
+ if (pfd < 0) {
+ if (pfd == -ENOENT || pfd == -EOPNOTSUPP) {
+ printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__);
+ test__skip();
+ }
+ if (!ASSERT_GE(pfd, 0, "perf_event_open"))
+ goto cleanup;
+ }
+
+ link = bpf_program__attach_perf_event(skel->progs.handle_pe, pfd);
+ if (!ASSERT_OK_PTR(link, "attach_perf_event"))
+ goto cleanup;
+
+ for (i = 0; i < 1000000; ++i)
+ ++j;
+
+ test_and_reset_skel(skel, -EBUSY /* in nmi, irq_work is busy */);
+cleanup:
+ bpf_link__destroy(link);
+ close(pfd);
+ /* caller will clean up skel */
+}
+
+static void test_find_vma_kprobe(struct find_vma *skel)
+{
+ int err;
+
+ err = find_vma__attach(skel);
+ if (!ASSERT_OK(err, "get_branch_snapshot__attach"))
+ return; /* caller will cleanup skel */
+
+ getpgid(skel->bss->target_pid);
+ test_and_reset_skel(skel, -ENOENT /* could not find vma for ptr 0 */);
+}
+
+void serial_test_find_vma(void)
+{
+ struct find_vma *skel;
+
+ skel = find_vma__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "find_vma__open_and_load"))
+ return;
+
+ skel->bss->target_pid = getpid();
+ skel->bss->addr = (__u64)test_find_vma_pe;
+
+ test_find_vma_pe(skel);
+ usleep(100000); /* allow the irq_work to finish */
+ test_find_vma_kprobe(skel);
+
+ find_vma__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/find_vma.c b/tools/testing/selftests/bpf/progs/find_vma.c
new file mode 100644
index 0000000000000..2776718a54e29
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/find_vma.c
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct callback_ctx {
+ int dummy;
+};
+
+#define VM_EXEC 0x00000004
+#define DNAME_INLINE_LEN 32
+
+pid_t target_pid = 0;
+char d_iname[DNAME_INLINE_LEN] = {0};
+__u32 found_vm_exec = 0;
+__u64 addr = 0;
+int find_zero_ret = -1;
+int find_addr_ret = -1;
+
+static __u64
+check_vma(struct task_struct *task, struct vm_area_struct *vma,
+ struct callback_ctx *data)
+{
+ if (vma->vm_file)
+ bpf_probe_read_kernel_str(d_iname, DNAME_INLINE_LEN - 1,
+ vma->vm_file->f_path.dentry->d_iname);
+
+ /* check for VM_EXEC */
+ if (vma->vm_flags & VM_EXEC)
+ found_vm_exec = 1;
+
+ return 0;
+}
+
+SEC("kprobe/__x64_sys_getpgid")
+int handle_getpid(void)
+{
+ struct task_struct *task = bpf_get_current_task_btf();
+ struct callback_ctx data = {0};
+
+ if (task->pid != target_pid)
+ return 0;
+
+ find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0);
+
+ /* this should return -ENOENT */
+ find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0);
+ return 0;
+}
+
+SEC("perf_event")
+int handle_pe(void)
+{
+ struct task_struct *task = bpf_get_current_task_btf();
+ struct callback_ctx data = {0};
+
+ if (task->pid != target_pid)
+ return 0;
+
+ find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0);
+
+ /* In NMI, this should return -EBUSY, as the previous call is using
+ * the irq_work.
+ */
+ find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0);
+ return 0;
+}
--
2.30.2
Powered by blists - more mailing lists