diff options
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/file_reader.c | 113 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/file_reader.c | 145 | ||||
| -rw-r--r-- | tools/testing/selftests/bpf/progs/file_reader_fail.c | 52 |
3 files changed, 310 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/file_reader.c b/tools/testing/selftests/bpf/prog_tests/file_reader.c new file mode 100644 index 000000000000..2a034d43b73e --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/file_reader.c @@ -0,0 +1,113 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include <test_progs.h> +#include <network_helpers.h> +#include "file_reader.skel.h" +#include "file_reader_fail.skel.h" +#include <dlfcn.h> +#include <sys/mman.h> + +const char *user_ptr = "hello world"; +char file_contents[256000]; + +void *get_executable_base_addr(void) +{ + Dl_info info; + + if (!dladdr((void *)&get_executable_base_addr, &info)) { + fprintf(stderr, "dladdr failed\n"); + return NULL; + } + + return info.dli_fbase; +} + +static int initialize_file_contents(void) +{ + int fd, page_sz = sysconf(_SC_PAGESIZE); + ssize_t n = 0, cur, off; + void *addr; + + fd = open("/proc/self/exe", O_RDONLY); + if (!ASSERT_OK_FD(fd, "Open /proc/self/exe\n")) + return 1; + + do { + cur = read(fd, file_contents + n, sizeof(file_contents) - n); + if (!ASSERT_GT(cur, 0, "read success")) + break; + n += cur; + } while (n < sizeof(file_contents)); + + close(fd); + + if (!ASSERT_EQ(n, sizeof(file_contents), "Read /proc/self/exe\n")) + return 1; + + addr = get_executable_base_addr(); + if (!ASSERT_NEQ(addr, NULL, "get executable address")) + return 1; + + /* page-align base file address */ + addr = (void *)((unsigned long)addr & ~(page_sz - 1)); + + for (off = 0; off < sizeof(file_contents); off += page_sz) { + if (!ASSERT_OK(madvise(addr + off, page_sz, MADV_PAGEOUT), + "madvise pageout")) + return errno; + } + + return 0; +} + +static void run_test(const char *prog_name) +{ + struct file_reader *skel; + struct bpf_program *prog; + int err, fd; + + err = initialize_file_contents(); + if (!ASSERT_OK(err, "initialize file contents")) + return; + + skel = file_reader__open(); + if (!ASSERT_OK_PTR(skel, "file_reader__open")) + return; + + bpf_object__for_each_program(prog, skel->obj) { + bpf_program__set_autoload(prog, strcmp(bpf_program__name(prog), prog_name) == 0); + } + + memcpy(skel->bss->user_buf, file_contents, sizeof(file_contents)); + skel->bss->pid = getpid(); + + err = file_reader__load(skel); + if (!ASSERT_OK(err, "file_reader__load")) + goto cleanup; + + err = file_reader__attach(skel); + if (!ASSERT_OK(err, "file_reader__attach")) + goto cleanup; + + fd = open("/proc/self/exe", O_RDONLY); + if (fd >= 0) + close(fd); + + ASSERT_EQ(skel->bss->err, 0, "err"); + ASSERT_EQ(skel->bss->run_success, 1, "run_success"); +cleanup: + file_reader__destroy(skel); +} + +void test_file_reader(void) +{ + if (test__start_subtest("on_open_expect_fault")) + run_test("on_open_expect_fault"); + + if (test__start_subtest("on_open_validate_file_read")) + run_test("on_open_validate_file_read"); + + if (test__start_subtest("negative")) + RUN_TESTS(file_reader_fail); +} diff --git a/tools/testing/selftests/bpf/progs/file_reader.c b/tools/testing/selftests/bpf/progs/file_reader.c new file mode 100644 index 000000000000..2585f83b0ce5 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/file_reader.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include <vmlinux.h> +#include <string.h> +#include <stdbool.h> +#include <bpf/bpf_tracing.h> +#include "bpf_misc.h" +#include "errno.h" + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} arrmap SEC(".maps"); + +struct elem { + struct file *file; + struct bpf_task_work tw; +}; + +char user_buf[256000]; +char tmp_buf[256000]; + +int pid = 0; +int err, run_success = 0; + +static int validate_file_read(struct file *file); +static int task_work_callback(struct bpf_map *map, void *key, void *value); + +SEC("lsm/file_open") +int on_open_expect_fault(void *c) +{ + struct bpf_dynptr dynptr; + struct file *file; + int local_err = 1; + __u32 user_buf_sz = sizeof(user_buf); + + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 0; + + file = bpf_get_task_exe_file(bpf_get_current_task_btf()); + if (!file) + return 0; + + if (bpf_dynptr_from_file(file, 0, &dynptr)) + goto out; + + local_err = bpf_dynptr_read(tmp_buf, user_buf_sz, &dynptr, 0, 0); + if (local_err == -EFAULT) { /* Expect page fault */ + local_err = 0; + run_success = 1; + } +out: + bpf_dynptr_file_discard(&dynptr); + if (local_err) + err = local_err; + bpf_put_file(file); + return 0; +} + +SEC("lsm/file_open") +int on_open_validate_file_read(void *c) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct elem *work; + int key = 0; + + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 0; + + work = bpf_map_lookup_elem(&arrmap, &key); + if (!work) { + err = 1; + return 0; + } + bpf_task_work_schedule_signal(task, &work->tw, &arrmap, task_work_callback, NULL); + return 0; +} + +/* Called in a sleepable context, read 256K bytes, cross check with user space read data */ +static int task_work_callback(struct bpf_map *map, void *key, void *value) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct file *file = bpf_get_task_exe_file(task); + + if (!file) + return 0; + + err = validate_file_read(file); + if (!err) + run_success = 1; + bpf_put_file(file); + return 0; +} + +static int verify_dynptr_read(struct bpf_dynptr *ptr, u32 off, char *user_buf, u32 len) +{ + int i; + + if (bpf_dynptr_read(tmp_buf, len, ptr, off, 0)) + return 1; + + /* Verify file contents read from BPF is the same as the one read from userspace */ + bpf_for(i, 0, len) + { + if (tmp_buf[i] != user_buf[i]) + return 1; + } + return 0; +} + +static int validate_file_read(struct file *file) +{ + struct bpf_dynptr dynptr; + int loc_err = 1, off; + __u32 user_buf_sz = sizeof(user_buf); + + if (bpf_dynptr_from_file(file, 0, &dynptr)) + goto cleanup; + + loc_err = verify_dynptr_read(&dynptr, 0, user_buf, user_buf_sz); + off = 1; + loc_err = loc_err ?: verify_dynptr_read(&dynptr, off, user_buf + off, user_buf_sz - off); + off = user_buf_sz - 1; + loc_err = loc_err ?: verify_dynptr_read(&dynptr, off, user_buf + off, user_buf_sz - off); + /* Read file with random offset and length */ + off = 4097; + loc_err = loc_err ?: verify_dynptr_read(&dynptr, off, user_buf + off, 100); + + /* Adjust dynptr, verify read */ + loc_err = loc_err ?: bpf_dynptr_adjust(&dynptr, off, off + 1); + loc_err = loc_err ?: verify_dynptr_read(&dynptr, 0, user_buf + off, 1); + /* Can't read more than 1 byte */ + loc_err = loc_err ?: verify_dynptr_read(&dynptr, 0, user_buf + off, 2) == 0; + /* Can't read with far offset */ + loc_err = loc_err ?: verify_dynptr_read(&dynptr, 1, user_buf + off, 1) == 0; + +cleanup: + bpf_dynptr_file_discard(&dynptr); + return loc_err; +} diff --git a/tools/testing/selftests/bpf/progs/file_reader_fail.c b/tools/testing/selftests/bpf/progs/file_reader_fail.c new file mode 100644 index 000000000000..32fe28ed2439 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/file_reader_fail.c @@ -0,0 +1,52 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */ + +#include <vmlinux.h> +#include <string.h> +#include <stdbool.h> +#include <bpf/bpf_tracing.h> +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +int err; +void *user_ptr; + +SEC("lsm/file_open") +__failure +__msg("Unreleased reference id=") +int on_nanosleep_unreleased_ref(void *ctx) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct file *file = bpf_get_task_exe_file(task); + struct bpf_dynptr dynptr; + + if (!file) + return 0; + + err = bpf_dynptr_from_file(file, 0, &dynptr); + return err ? 1 : 0; +} + +SEC("xdp") +__failure +__msg("Expected a dynptr of type file as arg #0") +int xdp_wrong_dynptr_type(struct xdp_md *xdp) +{ + struct bpf_dynptr dynptr; + + bpf_dynptr_from_xdp(xdp, 0, &dynptr); + bpf_dynptr_file_discard(&dynptr); + return 0; +} + +SEC("xdp") +__failure +__msg("Expected an initialized dynptr as arg #0") +int xdp_no_dynptr_type(struct xdp_md *xdp) +{ + struct bpf_dynptr dynptr; + + bpf_dynptr_file_discard(&dynptr); + return 0; +} |