diff options
Diffstat (limited to 'tools/testing/selftests/filesystems/binderfs')
4 files changed, 552 insertions, 0 deletions
diff --git a/tools/testing/selftests/filesystems/binderfs/.gitignore b/tools/testing/selftests/filesystems/binderfs/.gitignore new file mode 100644 index 000000000..8e5cf9084 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +binderfs_test diff --git a/tools/testing/selftests/filesystems/binderfs/Makefile b/tools/testing/selftests/filesystems/binderfs/Makefile new file mode 100644 index 000000000..c2f7cef91 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 + +CFLAGS += $(KHDR_INCLUDES) -pthread +TEST_GEN_PROGS := binderfs_test + +binderfs_test: binderfs_test.c ../../kselftest.h ../../kselftest_harness.h + +include ../../lib.mk diff --git a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c new file mode 100644 index 000000000..5f362c0fd --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c @@ -0,0 +1,540 @@ +// SPDX-License-Identifier: GPL-2.0 + +#define _GNU_SOURCE +#include <errno.h> +#include <fcntl.h> +#include <pthread.h> +#include <sched.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/fsuid.h> +#include <sys/ioctl.h> +#include <sys/mount.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/sysinfo.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> +#include <linux/android/binder.h> +#include <linux/android/binderfs.h> + +#include "../../kselftest_harness.h" + +#define DEFAULT_THREADS 4 + +#define PTR_TO_INT(p) ((int)((intptr_t)(p))) +#define INT_TO_PTR(u) ((void *)((intptr_t)(u))) + +#define close_prot_errno_disarm(fd) \ + if (fd >= 0) { \ + int _e_ = errno; \ + close(fd); \ + errno = _e_; \ + fd = -EBADF; \ + } + +static void change_mountns(struct __test_metadata *_metadata) +{ + int ret; + + ret = unshare(CLONE_NEWNS); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to unshare mount namespace", + strerror(errno)); + } + + ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to mount / as private", + strerror(errno)); + } +} + +static int __do_binderfs_test(struct __test_metadata *_metadata) +{ + int fd, ret, saved_errno, result = 1; + size_t len; + ssize_t wret; + struct binderfs_device device = { 0 }; + struct binder_version version = { 0 }; + char binderfs_mntpt[] = P_tmpdir "/binderfs_XXXXXX", + device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME]; + static const char * const binder_features[] = { + "oneway_spam_detection", + "extended_error", + }; + + change_mountns(_metadata); + + EXPECT_NE(mkdtemp(binderfs_mntpt), NULL) { + TH_LOG("%s - Failed to create binderfs mountpoint", + strerror(errno)); + goto out; + } + + ret = mount(NULL, binderfs_mntpt, "binder", 0, 0); + EXPECT_EQ(ret, 0) { + if (errno == ENODEV) + SKIP(goto out, "binderfs missing"); + TH_LOG("%s - Failed to mount binderfs", strerror(errno)); + goto rmdir; + } + + /* success: binderfs mounted */ + + memcpy(device.name, "my-binder", strlen("my-binder")); + + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + fd = open(device_path, O_RDONLY | O_CLOEXEC); + EXPECT_GE(fd, 0) { + TH_LOG("%s - Failed to open binder-control device", + strerror(errno)); + goto umount; + } + + ret = ioctl(fd, BINDER_CTL_ADD, &device); + saved_errno = errno; + close(fd); + errno = saved_errno; + EXPECT_GE(ret, 0) { + TH_LOG("%s - Failed to allocate new binder device", + strerror(errno)); + goto umount; + } + + TH_LOG("Allocated new binder device with major %d, minor %d, and name %s", + device.major, device.minor, device.name); + + /* success: binder device allocation */ + + snprintf(device_path, sizeof(device_path), "%s/my-binder", binderfs_mntpt); + fd = open(device_path, O_CLOEXEC | O_RDONLY); + EXPECT_GE(fd, 0) { + TH_LOG("%s - Failed to open my-binder device", + strerror(errno)); + goto umount; + } + + ret = ioctl(fd, BINDER_VERSION, &version); + saved_errno = errno; + close(fd); + errno = saved_errno; + EXPECT_GE(ret, 0) { + TH_LOG("%s - Failed to open perform BINDER_VERSION request", + strerror(errno)); + goto umount; + } + + TH_LOG("Detected binder version: %d", version.protocol_version); + + /* success: binder transaction with binderfs binder device */ + + ret = unlink(device_path); + EXPECT_EQ(ret, 0) { + TH_LOG("%s - Failed to delete binder device", + strerror(errno)); + goto umount; + } + + /* success: binder device removal */ + + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + ret = unlink(device_path); + EXPECT_NE(ret, 0) { + TH_LOG("Managed to delete binder-control device"); + goto umount; + } + EXPECT_EQ(errno, EPERM) { + TH_LOG("%s - Failed to delete binder-control device but exited with unexpected error code", + strerror(errno)); + goto umount; + } + + /* success: binder-control device removal failed as expected */ + + for (int i = 0; i < ARRAY_SIZE(binder_features); i++) { + snprintf(device_path, sizeof(device_path), "%s/features/%s", + binderfs_mntpt, binder_features[i]); + fd = open(device_path, O_CLOEXEC | O_RDONLY); + EXPECT_GE(fd, 0) { + TH_LOG("%s - Failed to open binder feature: %s", + strerror(errno), binder_features[i]); + goto umount; + } + close(fd); + } + + /* success: binder feature files found */ + result = 0; + +umount: + ret = umount2(binderfs_mntpt, MNT_DETACH); + EXPECT_EQ(ret, 0) { + TH_LOG("%s - Failed to unmount binderfs", strerror(errno)); + } +rmdir: + ret = rmdir(binderfs_mntpt); + EXPECT_EQ(ret, 0) { + TH_LOG("%s - Failed to rmdir binderfs mount", strerror(errno)); + } +out: + return result; +} + +static int wait_for_pid(pid_t pid) +{ + int status, ret; + +again: + ret = waitpid(pid, &status, 0); + if (ret == -1) { + if (errno == EINTR) + goto again; + + return -1; + } + + if (!WIFEXITED(status)) + return -1; + + return WEXITSTATUS(status); +} + +static int setid_userns_root(void) +{ + if (setuid(0)) + return -1; + if (setgid(0)) + return -1; + + setfsuid(0); + setfsgid(0); + + return 0; +} + +enum idmap_type { + UID_MAP, + GID_MAP, +}; + +static ssize_t read_nointr(int fd, void *buf, size_t count) +{ + ssize_t ret; +again: + ret = read(fd, buf, count); + if (ret < 0 && errno == EINTR) + goto again; + + return ret; +} + +static ssize_t write_nointr(int fd, const void *buf, size_t count) +{ + ssize_t ret; +again: + ret = write(fd, buf, count); + if (ret < 0 && errno == EINTR) + goto again; + + return ret; +} + +static int write_id_mapping(enum idmap_type type, pid_t pid, const char *buf, + size_t buf_size) +{ + int fd; + int ret; + char path[4096]; + + if (type == GID_MAP) { + int setgroups_fd; + + snprintf(path, sizeof(path), "/proc/%d/setgroups", pid); + setgroups_fd = open(path, O_WRONLY | O_CLOEXEC | O_NOFOLLOW); + if (setgroups_fd < 0 && errno != ENOENT) + return -1; + + if (setgroups_fd >= 0) { + ret = write_nointr(setgroups_fd, "deny", sizeof("deny") - 1); + close_prot_errno_disarm(setgroups_fd); + if (ret != sizeof("deny") - 1) + return -1; + } + } + + switch (type) { + case UID_MAP: + ret = snprintf(path, sizeof(path), "/proc/%d/uid_map", pid); + break; + case GID_MAP: + ret = snprintf(path, sizeof(path), "/proc/%d/gid_map", pid); + break; + default: + return -1; + } + if (ret < 0 || ret >= sizeof(path)) + return -E2BIG; + + fd = open(path, O_WRONLY | O_CLOEXEC | O_NOFOLLOW); + if (fd < 0) + return -1; + + ret = write_nointr(fd, buf, buf_size); + close_prot_errno_disarm(fd); + if (ret != buf_size) + return -1; + + return 0; +} + +static void change_userns(struct __test_metadata *_metadata, int syncfds[2]) +{ + int ret; + char buf; + + close_prot_errno_disarm(syncfds[1]); + + ret = unshare(CLONE_NEWUSER); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to unshare user namespace", + strerror(errno)); + } + + ret = write_nointr(syncfds[0], "1", 1); + ASSERT_EQ(ret, 1) { + TH_LOG("write_nointr() failed"); + } + + ret = read_nointr(syncfds[0], &buf, 1); + ASSERT_EQ(ret, 1) { + TH_LOG("read_nointr() failed"); + } + + close_prot_errno_disarm(syncfds[0]); + + ASSERT_EQ(setid_userns_root(), 0) { + TH_LOG("setid_userns_root() failed"); + } +} + +static void change_idmaps(struct __test_metadata *_metadata, int syncfds[2], pid_t pid) +{ + int ret; + char buf; + char id_map[4096]; + + close_prot_errno_disarm(syncfds[0]); + + ret = read_nointr(syncfds[1], &buf, 1); + ASSERT_EQ(ret, 1) { + TH_LOG("read_nointr() failed"); + } + + snprintf(id_map, sizeof(id_map), "0 %d 1\n", getuid()); + ret = write_id_mapping(UID_MAP, pid, id_map, strlen(id_map)); + ASSERT_EQ(ret, 0) { + TH_LOG("write_id_mapping(UID_MAP) failed"); + } + + snprintf(id_map, sizeof(id_map), "0 %d 1\n", getgid()); + ret = write_id_mapping(GID_MAP, pid, id_map, strlen(id_map)); + ASSERT_EQ(ret, 0) { + TH_LOG("write_id_mapping(GID_MAP) failed"); + } + + ret = write_nointr(syncfds[1], "1", 1); + ASSERT_EQ(ret, 1) { + TH_LOG("write_nointr() failed"); + } + + close_prot_errno_disarm(syncfds[1]); +} + +struct __test_metadata *_thread_metadata; +static void *binder_version_thread(void *data) +{ + struct __test_metadata *_metadata = _thread_metadata; + int fd = PTR_TO_INT(data); + struct binder_version version = { 0 }; + int ret; + + ret = ioctl(fd, BINDER_VERSION, &version); + if (ret < 0) + TH_LOG("%s - Failed to open perform BINDER_VERSION request\n", + strerror(errno)); + + pthread_exit(data); +} + +/* + * Regression test: + * 2669b8b0c798 ("binder: prevent UAF for binderfs devices") + * f0fe2c0f050d ("binder: prevent UAF for binderfs devices II") + * 211b64e4b5b6 ("binderfs: use refcount for binder control devices too") + */ +TEST(binderfs_stress) +{ + int fds[1000]; + int syncfds[2]; + pid_t pid; + int fd, ret; + size_t len; + struct binderfs_device device = { 0 }; + char binderfs_mntpt[] = P_tmpdir "/binderfs_XXXXXX", + device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME]; + + ret = socketpair(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, syncfds); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to create socket pair", strerror(errno)); + } + + pid = fork(); + ASSERT_GE(pid, 0) { + TH_LOG("%s - Failed to fork", strerror(errno)); + close_prot_errno_disarm(syncfds[0]); + close_prot_errno_disarm(syncfds[1]); + } + + if (pid == 0) { + int i, j, k, nthreads; + pthread_attr_t attr; + pthread_t threads[DEFAULT_THREADS]; + change_userns(_metadata, syncfds); + change_mountns(_metadata); + + ASSERT_NE(mkdtemp(binderfs_mntpt), NULL) { + TH_LOG("%s - Failed to create binderfs mountpoint", + strerror(errno)); + } + + ret = mount(NULL, binderfs_mntpt, "binder", 0, 0); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to mount binderfs, check if CONFIG_ANDROID_BINDERFS is enabled in the running kernel", + strerror(errno)); + } + + for (int i = 0; i < ARRAY_SIZE(fds); i++) { + + snprintf(device_path, sizeof(device_path), + "%s/binder-control", binderfs_mntpt); + fd = open(device_path, O_RDONLY | O_CLOEXEC); + ASSERT_GE(fd, 0) { + TH_LOG("%s - Failed to open binder-control device", + strerror(errno)); + } + + memset(&device, 0, sizeof(device)); + snprintf(device.name, sizeof(device.name), "%d", i); + ret = ioctl(fd, BINDER_CTL_ADD, &device); + close_prot_errno_disarm(fd); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to allocate new binder device", + strerror(errno)); + } + + snprintf(device_path, sizeof(device_path), "%s/%d", + binderfs_mntpt, i); + fds[i] = open(device_path, O_RDONLY | O_CLOEXEC); + ASSERT_GE(fds[i], 0) { + TH_LOG("%s - Failed to open binder device", strerror(errno)); + } + } + + ret = umount2(binderfs_mntpt, MNT_DETACH); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to unmount binderfs", strerror(errno)); + rmdir(binderfs_mntpt); + } + + nthreads = get_nprocs_conf(); + if (nthreads > DEFAULT_THREADS) + nthreads = DEFAULT_THREADS; + + _thread_metadata = _metadata; + pthread_attr_init(&attr); + for (k = 0; k < ARRAY_SIZE(fds); k++) { + for (i = 0; i < nthreads; i++) { + ret = pthread_create(&threads[i], &attr, binder_version_thread, INT_TO_PTR(fds[k])); + if (ret) { + TH_LOG("%s - Failed to create thread %d", + strerror(errno), i); + break; + } + } + + for (j = 0; j < i; j++) { + void *fdptr = NULL; + + ret = pthread_join(threads[j], &fdptr); + if (ret) + TH_LOG("%s - Failed to join thread %d for fd %d", + strerror(errno), j, PTR_TO_INT(fdptr)); + } + } + pthread_attr_destroy(&attr); + + for (k = 0; k < ARRAY_SIZE(fds); k++) + close(fds[k]); + + exit(EXIT_SUCCESS); + } + + change_idmaps(_metadata, syncfds, pid); + + ret = wait_for_pid(pid); + ASSERT_EQ(ret, 0) { + TH_LOG("wait_for_pid() failed"); + } +} + +TEST(binderfs_test_privileged) +{ + if (geteuid() != 0) + SKIP(return, "Tests are not run as root. Skipping privileged tests"); + + if (__do_binderfs_test(_metadata)) + SKIP(return, "The Android binderfs filesystem is not available"); +} + +TEST(binderfs_test_unprivileged) +{ + int ret; + int syncfds[2]; + pid_t pid; + + ret = socketpair(PF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, syncfds); + ASSERT_EQ(ret, 0) { + TH_LOG("%s - Failed to create socket pair", strerror(errno)); + } + + pid = fork(); + ASSERT_GE(pid, 0) { + close_prot_errno_disarm(syncfds[0]); + close_prot_errno_disarm(syncfds[1]); + TH_LOG("%s - Failed to fork", strerror(errno)); + } + + if (pid == 0) { + change_userns(_metadata, syncfds); + if (__do_binderfs_test(_metadata)) + exit(2); + exit(EXIT_SUCCESS); + } + + change_idmaps(_metadata, syncfds, pid); + + ret = wait_for_pid(pid); + if (ret) { + if (ret == 2) + SKIP(return, "The Android binderfs filesystem is not available"); + ASSERT_EQ(ret, 0) { + TH_LOG("wait_for_pid() failed"); + } + } +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/filesystems/binderfs/config b/tools/testing/selftests/filesystems/binderfs/config new file mode 100644 index 000000000..7b4fc6ee6 --- /dev/null +++ b/tools/testing/selftests/filesystems/binderfs/config @@ -0,0 +1,2 @@ +CONFIG_ANDROID_BINDERFS=y +CONFIG_ANDROID_BINDER_IPC=y |