diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/filesystems/binderfs/Makefile | 4 | ||||
| -rw-r--r-- | tools/testing/selftests/filesystems/binderfs/binderfs_test.c | 498 |
2 files changed, 371 insertions, 131 deletions
diff --git a/tools/testing/selftests/filesystems/binderfs/Makefile b/tools/testing/selftests/filesystems/binderfs/Makefile index 58cb659b56b4..8af25ae96049 100644 --- a/tools/testing/selftests/filesystems/binderfs/Makefile +++ b/tools/testing/selftests/filesystems/binderfs/Makefile @@ -1,6 +1,8 @@ # SPDX-License-Identifier: GPL-2.0 -CFLAGS += -I../../../../../usr/include/ +CFLAGS += -I../../../../../usr/include/ -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 index 8c2ed962e1c7..8a6b507e34a8 100644 --- a/tools/testing/selftests/filesystems/binderfs/binderfs_test.c +++ b/tools/testing/selftests/filesystems/binderfs/binderfs_test.c @@ -3,114 +3,47 @@ #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.h" - -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 void write_to_file(const char *filename, const void *buf, size_t count, - int allowed_errno) -{ - int fd, saved_errno; - ssize_t ret; +#include "../../kselftest.h" +#include "../../kselftest_harness.h" - fd = open(filename, O_WRONLY | O_CLOEXEC); - if (fd < 0) - ksft_exit_fail_msg("%s - Failed to open file %s\n", - strerror(errno), filename); +#define DEFAULT_THREADS 4 - ret = write_nointr(fd, buf, count); - if (ret < 0) { - if (allowed_errno && (errno == allowed_errno)) { - close(fd); - return; - } +#define PTR_TO_INT(p) ((int)((intptr_t)(p))) +#define INT_TO_PTR(u) ((void *)((intptr_t)(u))) - goto on_error; +#define close_prot_errno_disarm(fd) \ + if (fd >= 0) { \ + int _e_ = errno; \ + close(fd); \ + errno = _e_; \ + fd = -EBADF; \ } - if ((size_t)ret != count) - goto on_error; - - close(fd); - return; - -on_error: - saved_errno = errno; - close(fd); - errno = saved_errno; - - if (ret < 0) - ksft_exit_fail_msg("%s - Failed to write to file %s\n", - strerror(errno), filename); - - ksft_exit_fail_msg("Failed to write to file %s\n", filename); -} - -static void change_to_userns(void) -{ - int ret; - uid_t uid; - gid_t gid; - /* {g,u}id_map files only allow a max of 4096 bytes written to them */ - char idmap[4096]; - - uid = getuid(); - gid = getgid(); - - ret = unshare(CLONE_NEWUSER); - if (ret < 0) - ksft_exit_fail_msg("%s - Failed to unshare user namespace\n", - strerror(errno)); - - write_to_file("/proc/self/setgroups", "deny", strlen("deny"), ENOENT); - - ret = snprintf(idmap, sizeof(idmap), "0 %d 1", uid); - if (ret < 0 || (size_t)ret >= sizeof(idmap)) - ksft_exit_fail_msg("%s - Failed to prepare uid mapping\n", - strerror(errno)); - - write_to_file("/proc/self/uid_map", idmap, strlen(idmap), 0); - - ret = snprintf(idmap, sizeof(idmap), "0 %d 1", gid); - if (ret < 0 || (size_t)ret >= sizeof(idmap)) - ksft_exit_fail_msg("%s - Failed to prepare uid mapping\n", - strerror(errno)); - - write_to_file("/proc/self/gid_map", idmap, strlen(idmap), 0); - - ret = setgid(0); - if (ret) - ksft_exit_fail_msg("%s - Failed to setgid(0)\n", - strerror(errno)); +#define log_exit(format, ...) \ + ({ \ + fprintf(stderr, format "\n", ##__VA_ARGS__); \ + exit(EXIT_FAILURE); \ + }) - ret = setuid(0); - if (ret) - ksft_exit_fail_msg("%s - Failed to setgid(0)\n", - strerror(errno)); -} - -static void change_to_mountns(void) +static void change_mountns(void) { int ret; @@ -132,36 +65,31 @@ static void rmdir_protect_errno(const char *dir) errno = saved_errno; } -static void __do_binderfs_test(void) +static int __do_binderfs_test(void) { int fd, ret, saved_errno; size_t len; ssize_t wret; - bool keep = false; 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]; - change_to_mountns(); - - ret = mkdir("/dev/binderfs", 0755); - if (ret < 0) { - if (errno != EEXIST) - ksft_exit_fail_msg( - "%s - Failed to create binderfs mountpoint\n", - strerror(errno)); + change_mountns(); - keep = true; - } + if (!mkdtemp(binderfs_mntpt)) + ksft_exit_fail_msg( + "%s - Failed to create binderfs mountpoint\n", + strerror(errno)); - ret = mount(NULL, "/dev/binderfs", "binder", 0, 0); + ret = mount(NULL, binderfs_mntpt, "binder", 0, 0); if (ret < 0) { if (errno != ENODEV) ksft_exit_fail_msg("%s - Failed to mount binderfs\n", strerror(errno)); - keep ? : rmdir_protect_errno("/dev/binderfs"); - ksft_exit_skip( - "The Android binderfs filesystem is not available\n"); + rmdir_protect_errno(binderfs_mntpt); + return 1; } /* binderfs mount test passed */ @@ -169,7 +97,8 @@ static void __do_binderfs_test(void) memcpy(device.name, "my-binder", strlen("my-binder")); - fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC); + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + fd = open(device_path, O_RDONLY | O_CLOEXEC); if (fd < 0) ksft_exit_fail_msg( "%s - Failed to open binder-control device\n", @@ -180,7 +109,7 @@ static void __do_binderfs_test(void) close(fd); errno = saved_errno; if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to allocate new binder device\n", strerror(errno)); @@ -193,9 +122,10 @@ static void __do_binderfs_test(void) /* binder device allocation test passed */ ksft_inc_pass_cnt(); - fd = open("/dev/binderfs/my-binder", O_CLOEXEC | O_RDONLY); + snprintf(device_path, sizeof(device_path), "%s/my-binder", binderfs_mntpt); + fd = open(device_path, O_CLOEXEC | O_RDONLY); if (fd < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("%s - Failed to open my-binder device\n", strerror(errno)); } @@ -205,7 +135,7 @@ static void __do_binderfs_test(void) close(fd); errno = saved_errno; if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to open perform BINDER_VERSION request\n", strerror(errno)); @@ -217,9 +147,9 @@ static void __do_binderfs_test(void) /* binder transaction with binderfs binder device passed */ ksft_inc_pass_cnt(); - ret = unlink("/dev/binderfs/my-binder"); + ret = unlink(device_path); if (ret < 0) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("%s - Failed to delete binder device\n", strerror(errno)); } @@ -227,12 +157,13 @@ static void __do_binderfs_test(void) /* binder device removal passed */ ksft_inc_pass_cnt(); - ret = unlink("/dev/binderfs/binder-control"); + snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt); + ret = unlink(device_path); if (!ret) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg("Managed to delete binder-control device\n"); } else if (errno != EPERM) { - keep ? : rmdir_protect_errno("/dev/binderfs"); + rmdir_protect_errno(binderfs_mntpt); ksft_exit_fail_msg( "%s - Failed to delete binder-control device but exited with unexpected error code\n", strerror(errno)); @@ -242,34 +173,341 @@ static void __do_binderfs_test(void) ksft_inc_xfail_cnt(); on_error: - ret = umount2("/dev/binderfs", MNT_DETACH); - keep ?: rmdir_protect_errno("/dev/binderfs"); + ret = umount2(binderfs_mntpt, MNT_DETACH); + rmdir_protect_errno(binderfs_mntpt); if (ret < 0) ksft_exit_fail_msg("%s - Failed to unmount binderfs\n", strerror(errno)); /* binderfs unmount test passed */ ksft_inc_pass_cnt(); + return 0; } -static void binderfs_test_privileged() +static int wait_for_pid(pid_t pid) { - if (geteuid() != 0) - ksft_print_msg( - "Tests are not run as root. Skipping privileged tests\n"); - else - __do_binderfs_test(); + 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(int syncfds[2]) +{ + int ret; + char buf; + + close_prot_errno_disarm(syncfds[1]); + + ret = unshare(CLONE_NEWUSER); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to unshare user namespace\n", + strerror(errno)); + + ret = write_nointr(syncfds[0], "1", 1); + if (ret != 1) + ksft_exit_fail_msg("write_nointr() failed\n"); + + ret = read_nointr(syncfds[0], &buf, 1); + if (ret != 1) + ksft_exit_fail_msg("read_nointr() failed\n"); + + close_prot_errno_disarm(syncfds[0]); + + if (setid_userns_root()) + ksft_exit_fail_msg("setid_userns_root() failed"); +} + +static void change_idmaps(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); + if (ret != 1) + ksft_exit_fail_msg("read_nointr() failed\n"); + + snprintf(id_map, sizeof(id_map), "0 %d 1\n", getuid()); + ret = write_id_mapping(UID_MAP, pid, id_map, strlen(id_map)); + if (ret) + ksft_exit_fail_msg("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)); + if (ret) + ksft_exit_fail_msg("write_id_mapping(GID_MAP) failed"); + + ret = write_nointr(syncfds[1], "1", 1); + if (ret != 1) + ksft_exit_fail_msg("write_nointr() failed"); + + close_prot_errno_disarm(syncfds[1]); } -static void binderfs_test_unprivileged() +static void *binder_version_thread(void *data) { - change_to_userns(); - __do_binderfs_test(); + int fd = PTR_TO_INT(data); + struct binder_version version = { 0 }; + int ret; + + ret = ioctl(fd, BINDER_VERSION, &version); + if (ret < 0) + ksft_print_msg("%s - Failed to open perform BINDER_VERSION request\n", strerror(errno)); + + pthread_exit(data); } -int main(int argc, char *argv[]) +/* + * 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) { - binderfs_test_privileged(); - binderfs_test_unprivileged(); - ksft_exit_pass(); + 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); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to create socket pair", strerror(errno)); + + pid = fork(); + if (pid < 0) { + close_prot_errno_disarm(syncfds[0]); + close_prot_errno_disarm(syncfds[1]); + ksft_exit_fail_msg("%s - Failed to fork", strerror(errno)); + } + + if (pid == 0) { + int i, j, k, nthreads; + pthread_attr_t attr; + pthread_t threads[DEFAULT_THREADS]; + change_userns(syncfds); + change_mountns(); + + if (!mkdtemp(binderfs_mntpt)) + log_exit("%s - Failed to create binderfs mountpoint\n", + strerror(errno)); + + ret = mount(NULL, binderfs_mntpt, "binder", 0, 0); + if (ret < 0) + log_exit("%s - Failed to mount binderfs\n", 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); + if (fd < 0) + log_exit("%s - Failed to open binder-control device\n", 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); + if (ret < 0) + log_exit("%s - Failed to allocate new binder device\n", strerror(errno)); + + snprintf(device_path, sizeof(device_path), "%s/%d", + binderfs_mntpt, i); + fds[i] = open(device_path, O_RDONLY | O_CLOEXEC); + if (fds[i] < 0) + log_exit("%s - Failed to open binder device\n", strerror(errno)); + } + + ret = umount2(binderfs_mntpt, MNT_DETACH); + rmdir_protect_errno(binderfs_mntpt); + if (ret < 0) + log_exit("%s - Failed to unmount binderfs\n", strerror(errno)); + + nthreads = get_nprocs_conf(); + if (nthreads > DEFAULT_THREADS) + nthreads = DEFAULT_THREADS; + + 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) { + ksft_print_msg("%s - Failed to create thread %d\n", strerror(errno), i); + break; + } + } + + for (j = 0; j < i; j++) { + void *fdptr = NULL; + + ret = pthread_join(threads[j], &fdptr); + if (ret) + ksft_print_msg("%s - Failed to join thread %d for fd %d\n", 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(syncfds, pid); + + ret = wait_for_pid(pid); + if (ret) + ksft_exit_fail_msg("wait_for_pid() failed"); } + +TEST(binderfs_test_privileged) +{ + if (geteuid() != 0) + XFAIL(return, "Tests are not run as root. Skipping privileged tests"); + + if (__do_binderfs_test() == 1) + XFAIL(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); + if (ret < 0) + ksft_exit_fail_msg("%s - Failed to create socket pair", strerror(errno)); + + pid = fork(); + if (pid < 0) { + close_prot_errno_disarm(syncfds[0]); + close_prot_errno_disarm(syncfds[1]); + ksft_exit_fail_msg("%s - Failed to fork", strerror(errno)); + } + + if (pid == 0) { + change_userns(syncfds); + if (__do_binderfs_test() == 1) + exit(2); + exit(EXIT_SUCCESS); + } + + change_idmaps(syncfds, pid); + + ret = wait_for_pid(pid); + if (ret) { + if (ret == 2) + XFAIL(return, "The Android binderfs filesystem is not available"); + else + ksft_exit_fail_msg("wait_for_pid() failed"); + } +} + +TEST_HARNESS_MAIN |