static bool read_package_list(struct fuse_global* global) {
pthread_mutex_lock(&global->lock);
global->package_to_appid->clear();
bool rc = packagelist_parse(package_parse_callback, global);
DLOG(INFO) << "read_package_list: found " << global->package_to_appid->size() << " packages";
// Regenerate ownership details using newly loaded mapping.
derive_permissions_recursive_locked(global->fuse_default, &global->root);
pthread_mutex_unlock(&global->lock);
return rc;
}
static void *reinit_thread_start(void * /*obj*/) {
prctl(PR_SET_NAME, "logd.daemon");
set_sched_policy(0, SP_BACKGROUND);
setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND);
setgid(AID_SYSTEM);
setuid(AID_SYSTEM);
while (reinit_running && !sem_wait(&reinit) && reinit_running) {
// uidToName Privileged Worker
if (uid) {
name = NULL;
packagelist_parse(package_list_parser_cb, NULL);
uid = 0;
sem_post(&uidName);
continue;
}
if (fdDmesg >= 0) {
static const char reinit_message[] = { KMSG_PRIORITY(LOG_INFO),
'l', 'o', 'g', 'd', '.', 'd', 'a', 'e', 'm', 'o', 'n', ':',
' ', 'r', 'e', 'i', 'n', 'i', 't', '\n' };
write(fdDmesg, reinit_message, sizeof(reinit_message));
}
// Anything that reads persist.<property>
if (logBuf) {
logBuf->init();
logBuf->initPrune(NULL);
}
if (logAudit) {
logAudit->allowSafeMode();
}
}
return NULL;
}
static void* reinit_thread_start(void* /*obj*/) {
prctl(PR_SET_NAME, "logd.daemon");
set_sched_policy(0, SP_BACKGROUND);
setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND);
// We should drop to AID_LOGD, if we are anything else, we have
// even lesser privileges and accept our fate.
gid_t groups[] = {
AID_SYSTEM, // search access to /data/system path
AID_PACKAGE_INFO, // readonly access to /data/system/packages.list
};
if (setgroups(arraysize(groups), groups) == -1) {
android::prdebug(
"logd.daemon: failed to set AID_SYSTEM AID_PACKAGE_INFO groups");
}
if (setgid(AID_LOGD) != 0) {
android::prdebug("logd.daemon: failed to set AID_LOGD gid");
}
if (setuid(AID_LOGD) != 0) {
android::prdebug("logd.daemon: failed to set AID_LOGD uid");
}
cap_t caps = cap_init();
(void)cap_clear(caps);
(void)cap_set_proc(caps);
(void)cap_free(caps);
while (reinit_running && !sem_wait(&reinit) && reinit_running) {
// uidToName Privileged Worker
if (uid) {
name = nullptr;
// if we got the perms wrong above, this would spam if we reported
// problems with acquisition of an uid name from the packages.
(void)packagelist_parse(package_list_parser_cb, nullptr);
uid = 0;
sem_post(&uidName);
continue;
}
if (fdDmesg >= 0) {
static const char reinit_message[] = { KMSG_PRIORITY(LOG_INFO),
'l',
'o',
'g',
'd',
'.',
'd',
'a',
'e',
'm',
'o',
'n',
':',
' ',
'r',
'e',
'i',
'n',
'i',
't',
'\n' };
write(fdDmesg, reinit_message, sizeof(reinit_message));
}
// Anything that reads persist.<property>
if (logBuf) {
logBuf->init();
logBuf->initPrune(nullptr);
}
android::ReReadEventLogTags();
}
return nullptr;
}
int main(int argc, char* argv[]) {
// Check arguments.
if (argc < 2) {
error(1, 0, "usage: run-as <package-name> [--user <uid>] <command> [<args>]\n");
}
// This program runs with CAP_SETUID and CAP_SETGID capabilities on Android
// production devices. Check user id of caller --- must be 'shell' or 'root'.
if (getuid() != AID_SHELL && getuid() != AID_ROOT) {
error(1, 0, "only 'shell' or 'root' users can run this program");
}
__user_cap_header_struct capheader;
__user_cap_data_struct capdata[2];
memset(&capheader, 0, sizeof(capheader));
memset(&capdata, 0, sizeof(capdata));
capheader.version = _LINUX_CAPABILITY_VERSION_3;
capdata[CAP_TO_INDEX(CAP_SETUID)].effective |= CAP_TO_MASK(CAP_SETUID);
capdata[CAP_TO_INDEX(CAP_SETGID)].effective |= CAP_TO_MASK(CAP_SETGID);
capdata[CAP_TO_INDEX(CAP_SETUID)].permitted |= CAP_TO_MASK(CAP_SETUID);
capdata[CAP_TO_INDEX(CAP_SETGID)].permitted |= CAP_TO_MASK(CAP_SETGID);
if (capset(&capheader, &capdata[0]) == -1) {
error(1, errno, "couldn't set capabilities");
}
char* pkgname = argv[1];
int cmd_argv_offset = 2;
// Get user_id from command line if provided.
int userId = 0;
if ((argc >= 4) && !strcmp(argv[2], "--user")) {
userId = atoi(argv[3]);
if (userId < 0) error(1, 0, "negative user id: %d", userId);
cmd_argv_offset += 2;
}
// Retrieve package information from system, switching egid so we can read the file.
gid_t old_egid = getegid();
if (setegid(AID_PACKAGE_INFO) == -1) error(1, errno, "setegid(AID_PACKAGE_INFO) failed");
pkg_info info;
memset(&info, 0, sizeof(info));
info.name = pkgname;
if (!packagelist_parse(packagelist_parse_callback, &info)) {
error(1, errno, "packagelist_parse failed");
}
if (info.uid == 0) {
error(1, 0, "unknown package: %s", pkgname);
}
if (setegid(old_egid) == -1) error(1, errno, "couldn't restore egid");
// Verify that user id is not too big.
if ((UID_MAX - info.uid) / AID_USER < (uid_t)userId) {
error(1, 0, "user id too big: %d", userId);
}
// Calculate user app ID.
uid_t userAppId = (AID_USER * userId) + info.uid;
// Reject system packages.
if (userAppId < AID_APP) {
error(1, 0, "package not an application: %s", pkgname);
}
// Reject any non-debuggable package.
if (!info.debuggable) {
error(1, 0, "package not debuggable: %s", pkgname);
}
// Check that the data directory path is valid.
if (!check_data_path(info.data_dir, userAppId)) {
error(1, 0, "package has corrupt installation: %s", pkgname);
}
// Ensure that we change all real/effective/saved IDs at the
// same time to avoid nasty surprises.
uid_t uid = userAppId;
uid_t gid = userAppId;
if (setresgid(gid, gid, gid) == -1) {
error(1, errno, "setresgid failed");
}
if (setresuid(uid, uid, uid) == -1) {
error(1, errno, "setresuid failed");
}
// Required if caller has uid and gid all non-zero.
memset(&capdata, 0, sizeof(capdata));
if (capset(&capheader, &capdata[0]) == -1) {
error(1, errno, "couldn't clear all capabilities");
}
if (selinux_android_setcontext(uid, 0, info.seinfo, pkgname) < 0) {
error(1, errno, "couldn't set SELinux security context");
}
// cd into the data directory, and set $HOME correspondingly.
if (TEMP_FAILURE_RETRY(chdir(info.data_dir)) == -1) {
error(1, errno, "couldn't chdir to package's data directory");
}
setenv("HOME", info.data_dir, 1);
// Reset parts of the environment, like su would.
setenv("PATH", _PATH_DEFPATH, 1);
unsetenv("IFS");
// Set the user-specific parts for this user.
passwd* pw = getpwuid(uid);
setenv("LOGNAME", pw->pw_name, 1);
setenv("SHELL", pw->pw_shell, 1);
setenv("USER", pw->pw_name, 1);
// User specified command for exec.
if ((argc >= cmd_argv_offset + 1) &&
(execvp(argv[cmd_argv_offset], argv+cmd_argv_offset) == -1)) {
error(1, errno, "exec failed for %s", argv[cmd_argv_offset]);
}
// Default exec shell.
execlp(_PATH_BSHELL, "sh", NULL);
error(1, errno, "exec failed");
}
int main(int argc, char* argv[]) {
// Check arguments.
if (argc < 2) {
error(1, 0, "usage: run-as <package-name> [--user <uid>] <command> [<args>]\n");
}
// This program runs with CAP_SETUID and CAP_SETGID capabilities on Android
// production devices. Check user id of caller --- must be 'shell' or 'root'.
if (getuid() != AID_SHELL && getuid() != AID_ROOT) {
error(1, 0, "only 'shell' or 'root' users can run this program");
}
// Some devices can disable running run-as, such as Chrome OS when running in
// non-developer mode.
if (android::base::GetBoolProperty("ro.boot.disable_runas", false)) {
error(1, 0, "run-as is disabled from the kernel commandline");
}
char* pkgname = argv[1];
int cmd_argv_offset = 2;
// Get user_id from command line if provided.
int userId = 0;
if ((argc >= 4) && !strcmp(argv[2], "--user")) {
userId = atoi(argv[3]);
if (userId < 0) error(1, 0, "negative user id: %d", userId);
cmd_argv_offset += 2;
}
// Retrieve package information from system, switching egid so we can read the file.
gid_t old_egid = getegid();
if (setegid(AID_PACKAGE_INFO) == -1) error(1, errno, "setegid(AID_PACKAGE_INFO) failed");
pkg_info info;
memset(&info, 0, sizeof(info));
info.name = pkgname;
if (!packagelist_parse(packagelist_parse_callback, &info)) {
error(1, errno, "packagelist_parse failed");
}
// Handle a multi-user data path
if (userId > 0) {
free(info.data_dir);
if (asprintf(&info.data_dir, "/data/user/%d/%s", userId, pkgname) == -1) {
error(1, errno, "asprintf failed");
}
}
if (info.uid == 0) {
error(1, 0, "unknown package: %s", pkgname);
}
if (setegid(old_egid) == -1) error(1, errno, "couldn't restore egid");
// Verify that user id is not too big.
if ((UID_MAX - info.uid) / AID_USER_OFFSET < (uid_t)userId) {
error(1, 0, "user id too big: %d", userId);
}
// Calculate user app ID.
uid_t userAppId = (AID_USER_OFFSET * userId) + info.uid;
// Reject system packages.
if (userAppId < AID_APP) {
error(1, 0, "package not an application: %s", pkgname);
}
// Reject any non-debuggable package.
if (!info.debuggable) {
error(1, 0, "package not debuggable: %s", pkgname);
}
// Check that the data directory path is valid.
if (!check_data_path(info.data_dir, userAppId)) {
error(1, 0, "package has corrupt installation: %s", pkgname);
}
// Ensure that we change all real/effective/saved IDs at the
// same time to avoid nasty surprises.
uid_t uid = userAppId;
uid_t gid = userAppId;
ScopedMinijail j(minijail_new());
minijail_change_uid(j.get(), uid);
minijail_change_gid(j.get(), gid);
minijail_keep_supplementary_gids(j.get());
minijail_enter(j.get());
std::string seinfo = std::string(info.seinfo) + ":fromRunAs";
if (selinux_android_setcontext(uid, 0, seinfo.c_str(), pkgname) < 0) {
error(1, errno, "couldn't set SELinux security context");
}
// cd into the data directory, and set $HOME correspondingly.
if (TEMP_FAILURE_RETRY(chdir(info.data_dir)) == -1) {
error(1, errno, "couldn't chdir to package's data directory");
}
setenv("HOME", info.data_dir, 1);
// Reset parts of the environment, like su would.
setenv("PATH", _PATH_DEFPATH, 1);
unsetenv("IFS");
// Set the user-specific parts for this user.
passwd* pw = getpwuid(uid);
setenv("LOGNAME", pw->pw_name, 1);
setenv("SHELL", pw->pw_shell, 1);
setenv("USER", pw->pw_name, 1);
// User specified command for exec.
if ((argc >= cmd_argv_offset + 1) &&
(execvp(argv[cmd_argv_offset], argv+cmd_argv_offset) == -1)) {
error(1, errno, "exec failed for %s", argv[cmd_argv_offset]);
}
// Default exec shell.
execlp(_PATH_BSHELL, "sh", NULL);
error(1, errno, "exec failed");
}
