541 lines
12 KiB
C
541 lines
12 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <pthread.h>
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#include <sched.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/fsuid.h>
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#include <sys/ioctl.h>
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#include <sys/mount.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/sysinfo.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <linux/android/binder.h>
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#include <linux/android/binderfs.h>
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#include "../../kselftest_harness.h"
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#define DEFAULT_THREADS 4
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#define PTR_TO_INT(p) ((int)((intptr_t)(p)))
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#define INT_TO_PTR(u) ((void *)((intptr_t)(u)))
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#define close_prot_errno_disarm(fd) \
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if (fd >= 0) { \
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int _e_ = errno; \
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close(fd); \
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errno = _e_; \
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fd = -EBADF; \
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}
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static void change_mountns(struct __test_metadata *_metadata)
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{
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int ret;
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ret = unshare(CLONE_NEWNS);
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ASSERT_EQ(ret, 0) {
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TH_LOG("%s - Failed to unshare mount namespace",
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strerror(errno));
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}
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ret = mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0);
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ASSERT_EQ(ret, 0) {
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TH_LOG("%s - Failed to mount / as private",
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strerror(errno));
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}
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}
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static int __do_binderfs_test(struct __test_metadata *_metadata)
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{
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int fd, ret, saved_errno, result = 1;
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size_t len;
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ssize_t wret;
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struct binderfs_device device = { 0 };
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struct binder_version version = { 0 };
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char binderfs_mntpt[] = P_tmpdir "/binderfs_XXXXXX",
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device_path[sizeof(P_tmpdir "/binderfs_XXXXXX/") + BINDERFS_MAX_NAME];
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static const char * const binder_features[] = {
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"oneway_spam_detection",
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"extended_error",
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};
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change_mountns(_metadata);
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EXPECT_NE(mkdtemp(binderfs_mntpt), NULL) {
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TH_LOG("%s - Failed to create binderfs mountpoint",
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strerror(errno));
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goto out;
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}
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ret = mount(NULL, binderfs_mntpt, "binder", 0, 0);
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EXPECT_EQ(ret, 0) {
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if (errno == ENODEV)
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SKIP(goto out, "binderfs missing");
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TH_LOG("%s - Failed to mount binderfs", strerror(errno));
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goto rmdir;
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}
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/* success: binderfs mounted */
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memcpy(device.name, "my-binder", strlen("my-binder"));
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snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt);
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fd = open(device_path, O_RDONLY | O_CLOEXEC);
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EXPECT_GE(fd, 0) {
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TH_LOG("%s - Failed to open binder-control device",
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strerror(errno));
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goto umount;
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}
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ret = ioctl(fd, BINDER_CTL_ADD, &device);
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saved_errno = errno;
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close(fd);
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errno = saved_errno;
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EXPECT_GE(ret, 0) {
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TH_LOG("%s - Failed to allocate new binder device",
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strerror(errno));
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goto umount;
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}
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TH_LOG("Allocated new binder device with major %d, minor %d, and name %s",
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device.major, device.minor, device.name);
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/* success: binder device allocation */
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snprintf(device_path, sizeof(device_path), "%s/my-binder", binderfs_mntpt);
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fd = open(device_path, O_CLOEXEC | O_RDONLY);
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EXPECT_GE(fd, 0) {
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TH_LOG("%s - Failed to open my-binder device",
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strerror(errno));
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goto umount;
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}
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ret = ioctl(fd, BINDER_VERSION, &version);
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saved_errno = errno;
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close(fd);
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errno = saved_errno;
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EXPECT_GE(ret, 0) {
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TH_LOG("%s - Failed to open perform BINDER_VERSION request",
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strerror(errno));
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goto umount;
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}
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TH_LOG("Detected binder version: %d", version.protocol_version);
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/* success: binder transaction with binderfs binder device */
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ret = unlink(device_path);
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EXPECT_EQ(ret, 0) {
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TH_LOG("%s - Failed to delete binder device",
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strerror(errno));
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goto umount;
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}
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/* success: binder device removal */
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snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt);
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ret = unlink(device_path);
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EXPECT_NE(ret, 0) {
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TH_LOG("Managed to delete binder-control device");
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goto umount;
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}
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EXPECT_EQ(errno, EPERM) {
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TH_LOG("%s - Failed to delete binder-control device but exited with unexpected error code",
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strerror(errno));
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goto umount;
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}
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/* success: binder-control device removal failed as expected */
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for (int i = 0; i < ARRAY_SIZE(binder_features); i++) {
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snprintf(device_path, sizeof(device_path), "%s/features/%s",
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binderfs_mntpt, binder_features[i]);
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fd = open(device_path, O_CLOEXEC | O_RDONLY);
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EXPECT_GE(fd, 0) {
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TH_LOG("%s - Failed to open binder feature: %s",
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strerror(errno), binder_features[i]);
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goto umount;
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}
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close(fd);
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}
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/* success: binder feature files found */
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result = 0;
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umount:
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ret = umount2(binderfs_mntpt, MNT_DETACH);
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EXPECT_EQ(ret, 0) {
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TH_LOG("%s - Failed to unmount binderfs", strerror(errno));
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}
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rmdir:
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ret = rmdir(binderfs_mntpt);
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EXPECT_EQ(ret, 0) {
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TH_LOG("%s - Failed to rmdir binderfs mount", strerror(errno));
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}
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out:
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return result;
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}
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static int wait_for_pid(pid_t pid)
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{
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int status, ret;
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again:
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ret = waitpid(pid, &status, 0);
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if (ret == -1) {
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if (errno == EINTR)
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goto again;
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return -1;
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}
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if (!WIFEXITED(status))
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return -1;
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return WEXITSTATUS(status);
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}
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static int setid_userns_root(void)
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{
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if (setuid(0))
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return -1;
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if (setgid(0))
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return -1;
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setfsuid(0);
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setfsgid(0);
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return 0;
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}
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enum idmap_type {
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UID_MAP,
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GID_MAP,
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};
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static ssize_t read_nointr(int fd, void *buf, size_t count)
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{
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ssize_t ret;
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again:
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ret = read(fd, buf, count);
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if (ret < 0 && errno == EINTR)
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goto again;
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return ret;
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}
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static ssize_t write_nointr(int fd, const void *buf, size_t count)
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{
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ssize_t ret;
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again:
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ret = write(fd, buf, count);
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if (ret < 0 && errno == EINTR)
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goto again;
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return ret;
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}
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static int write_id_mapping(enum idmap_type type, pid_t pid, const char *buf,
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size_t buf_size)
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{
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int fd;
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int ret;
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char path[4096];
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if (type == GID_MAP) {
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int setgroups_fd;
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snprintf(path, sizeof(path), "/proc/%d/setgroups", pid);
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setgroups_fd = open(path, O_WRONLY | O_CLOEXEC | O_NOFOLLOW);
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if (setgroups_fd < 0 && errno != ENOENT)
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return -1;
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if (setgroups_fd >= 0) {
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ret = write_nointr(setgroups_fd, "deny", sizeof("deny") - 1);
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close_prot_errno_disarm(setgroups_fd);
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if (ret != sizeof("deny") - 1)
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return -1;
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}
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}
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switch (type) {
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case UID_MAP:
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ret = snprintf(path, sizeof(path), "/proc/%d/uid_map", pid);
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break;
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case GID_MAP:
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ret = snprintf(path, sizeof(path), "/proc/%d/gid_map", pid);
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break;
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default:
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return -1;
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}
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if (ret < 0 || ret >= sizeof(path))
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return -E2BIG;
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fd = open(path, O_WRONLY | O_CLOEXEC | O_NOFOLLOW);
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if (fd < 0)
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return -1;
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ret = write_nointr(fd, buf, buf_size);
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close_prot_errno_disarm(fd);
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if (ret != buf_size)
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return -1;
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return 0;
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}
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static void change_userns(struct __test_metadata *_metadata, int syncfds[2])
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{
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int ret;
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char buf;
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close_prot_errno_disarm(syncfds[1]);
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ret = unshare(CLONE_NEWUSER);
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ASSERT_EQ(ret, 0) {
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TH_LOG("%s - Failed to unshare user namespace",
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strerror(errno));
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}
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ret = write_nointr(syncfds[0], "1", 1);
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ASSERT_EQ(ret, 1) {
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TH_LOG("write_nointr() failed");
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}
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ret = read_nointr(syncfds[0], &buf, 1);
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ASSERT_EQ(ret, 1) {
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TH_LOG("read_nointr() failed");
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}
|
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close_prot_errno_disarm(syncfds[0]);
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ASSERT_EQ(setid_userns_root(), 0) {
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TH_LOG("setid_userns_root() failed");
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}
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}
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static void change_idmaps(struct __test_metadata *_metadata, int syncfds[2], pid_t pid)
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{
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int ret;
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char buf;
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char id_map[4096];
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close_prot_errno_disarm(syncfds[0]);
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ret = read_nointr(syncfds[1], &buf, 1);
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ASSERT_EQ(ret, 1) {
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TH_LOG("read_nointr() failed");
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}
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|
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snprintf(id_map, sizeof(id_map), "0 %d 1\n", getuid());
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ret = write_id_mapping(UID_MAP, pid, id_map, strlen(id_map));
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ASSERT_EQ(ret, 0) {
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TH_LOG("write_id_mapping(UID_MAP) failed");
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|
}
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|
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snprintf(id_map, sizeof(id_map), "0 %d 1\n", getgid());
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ret = write_id_mapping(GID_MAP, pid, id_map, strlen(id_map));
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ASSERT_EQ(ret, 0) {
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TH_LOG("write_id_mapping(GID_MAP) failed");
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|
}
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|
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ret = write_nointr(syncfds[1], "1", 1);
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ASSERT_EQ(ret, 1) {
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TH_LOG("write_nointr() failed");
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|
}
|
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|
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close_prot_errno_disarm(syncfds[1]);
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|
}
|
||
|
|
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|
struct __test_metadata *_thread_metadata;
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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
|