mirror of https://gitee.com/openkylin/linux.git
binderfs: add stress test for binderfs binder devices
This adds a stress test that should hopefully help us catch regressions for [1], [2], and [3]. [1]:2669b8b0c7("binder: prevent UAF for binderfs devices") [2]:f0fe2c0f05("binder: prevent UAF for binderfs devices II") [3]:211b64e4b5("binderfs: use refcount for binder control devices too") Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200313152420.138777-3-christian.brauner@ubuntu.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christian Brauner
Greg Kroah-Hartman
parent
ad29ace2e2
commit
e48d117436
|
|
@ -1,6 +1,6 @@
|
|||
# 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
|
||||
|
|
|
|||
|
|
@ -3,15 +3,20 @@
|
|||
#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>
|
||||
|
|
@ -19,100 +24,26 @@
|
|||
#include "../../kselftest.h"
|
||||
#include "../../kselftest_harness.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;
|
||||
#define DEFAULT_THREADS 4
|
||||
|
||||
return ret;
|
||||
}
|
||||
#define PTR_TO_INT(p) ((int)((intptr_t)(p)))
|
||||
#define INT_TO_PTR(u) ((void *)((intptr_t)(u)))
|
||||
|
||||
static void write_to_file(const char *filename, const void *buf, size_t count,
|
||||
int allowed_errno)
|
||||
{
|
||||
int fd, saved_errno;
|
||||
ssize_t ret;
|
||||
|
||||
fd = open(filename, O_WRONLY | O_CLOEXEC);
|
||||
if (fd < 0)
|
||||
ksft_exit_fail_msg("%s - Failed to open file %s\n",
|
||||
strerror(errno), filename);
|
||||
|
||||
ret = write_nointr(fd, buf, count);
|
||||
if (ret < 0) {
|
||||
if (allowed_errno && (errno == allowed_errno)) {
|
||||
close(fd);
|
||||
return;
|
||||
}
|
||||
|
||||
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;
|
||||
#define log_exit(format, ...) \
|
||||
({ \
|
||||
fprintf(stderr, format "\n", ##__VA_ARGS__); \
|
||||
exit(EXIT_FAILURE); \
|
||||
})
|
||||
|
||||
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));
|
||||
|
||||
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;
|
||||
|
||||
|
|
@ -144,7 +75,7 @@ static int __do_binderfs_test(void)
|
|||
char binderfs_mntpt[] = P_tmpdir "/binderfs_XXXXXX",
|
||||
device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME];
|
||||
|
||||
change_to_mountns();
|
||||
change_mountns();
|
||||
|
||||
if (!mkdtemp(binderfs_mntpt))
|
||||
ksft_exit_fail_msg(
|
||||
|
|
@ -253,6 +184,288 @@ static int __do_binderfs_test(void)
|
|||
return 0;
|
||||
}
|
||||
|
||||
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(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 *binder_version_thread(void *data)
|
||||
{
|
||||
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);
|
||||
}
|
||||
|
||||
/*
|
||||
* 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);
|
||||
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)
|
||||
|
|
@ -264,10 +477,37 @@ TEST(binderfs_test_privileged)
|
|||
|
||||
TEST(binderfs_test_unprivileged)
|
||||
{
|
||||
change_to_userns();
|
||||
int ret;
|
||||
int syncfds[2];
|
||||
pid_t pid;
|
||||
|
||||
if (__do_binderfs_test() == 1)
|
||||
XFAIL(return, "The Android binderfs filesystem is not available");
|
||||
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
|
||||
|
|
|
|||
Loading…
Reference in New Issue