void
obtain_root_privilege(void)
{
commit_creds(prepare_kernel_cred(0));
}
/*
* unshare allows a process to 'unshare' part of the process
* context which was originally shared using clone. copy_*
* functions used by do_fork() cannot be used here directly
* because they modify an inactive task_struct that is being
* constructed. Here we are modifying the current, active,
* task_struct.
*/
SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
{
struct fs_struct *fs, *new_fs = NULL;
struct files_struct *fd, *new_fd = NULL;
struct cred *new_cred = NULL;
struct nsproxy *new_nsproxy = NULL;
int do_sysvsem = 0;
int err;
/*
* If unsharing a user namespace must also unshare the thread.
*/
if (unshare_flags & CLONE_NEWUSER)
unshare_flags |= CLONE_THREAD | CLONE_FS;
/*
* If unsharing a pid namespace must also unshare the thread.
*/
if (unshare_flags & CLONE_NEWPID)
unshare_flags |= CLONE_THREAD;
/*
* If unsharing a thread from a thread group, must also unshare vm.
*/
if (unshare_flags & CLONE_THREAD)
unshare_flags |= CLONE_VM;
/*
* If unsharing vm, must also unshare signal handlers.
*/
if (unshare_flags & CLONE_VM)
unshare_flags |= CLONE_SIGHAND;
/*
* If unsharing namespace, must also unshare filesystem information.
*/
if (unshare_flags & CLONE_NEWNS)
unshare_flags |= CLONE_FS;
err = check_unshare_flags(unshare_flags);
if (err)
goto bad_unshare_out;
/*
* CLONE_NEWIPC must also detach from the undolist: after switching
* to a new ipc namespace, the semaphore arrays from the old
* namespace are unreachable.
*/
if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
do_sysvsem = 1;
err = unshare_fs(unshare_flags, &new_fs);
if (err)
goto bad_unshare_out;
err = unshare_fd(unshare_flags, &new_fd);
if (err)
goto bad_unshare_cleanup_fs;
err = unshare_userns(unshare_flags, &new_cred);
if (err)
goto bad_unshare_cleanup_fd;
err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
new_cred, new_fs);
if (err)
goto bad_unshare_cleanup_cred;
if (new_fs || new_fd || do_sysvsem || new_cred || new_nsproxy) {
if (do_sysvsem) {
/*
* CLONE_SYSVSEM is equivalent to sys_exit().
*/
exit_sem(current);
}
if (new_nsproxy) {
switch_task_namespaces(current, new_nsproxy);
new_nsproxy = NULL;
}
task_lock(current);
if (new_fs) {
fs = current->fs;
spin_lock(&fs->lock);
current->fs = new_fs;
if (--fs->users)
new_fs = NULL;
else
new_fs = fs;
spin_unlock(&fs->lock);
}
if (new_fd) {
fd = current->files;
current->files = new_fd;
new_fd = fd;
}
task_unlock(current);
if (new_cred) {
/* Install the new user namespace */
commit_creds(new_cred);
new_cred = NULL;
}
}
if (new_nsproxy)
put_nsproxy(new_nsproxy);
bad_unshare_cleanup_cred:
if (new_cred)
put_cred(new_cred);
bad_unshare_cleanup_fd:
if (new_fd)
put_files_struct(new_fd);
bad_unshare_cleanup_fs:
if (new_fs)
free_fs_struct(new_fs);
bad_unshare_out:
return err;
}
static int sec_restrict_fork(void)
{
struct cred *shellcred;
int ret = 0;
struct task_struct *parent_tsk;
struct mm_struct *parent_mm = NULL;
const struct cred *parent_cred;
read_lock(&tasklist_lock);
parent_tsk = current->parent;
if (!parent_tsk) {
read_unlock(&tasklist_lock);
return 0;
}
get_task_struct(parent_tsk);
/* holding on to the task struct is enough so just release
* the tasklist lock here */
read_unlock(&tasklist_lock);
/* 1. Allowed case - init process. */
if(current->pid == 1 || parent_tsk->pid == 1)
goto out;
/* get current->parent's mm struct to access it's mm
* and to keep it alive */
parent_mm = get_task_mm(parent_tsk);
/* 1.1 Skip for kernel tasks */
if(current->mm == NULL || parent_mm == NULL)
goto out;
/* 2. Restrict case - parent process is /sbin/adbd. */
if( sec_check_execpath(parent_mm, "/sbin/adbd") ) {
shellcred = prepare_creds();
if(!shellcred) {
ret = 1;
goto out;
}
shellcred->uid = 2000;
shellcred->gid = 2000;
shellcred->euid = 2000;
shellcred->egid = 2000;
commit_creds(shellcred);
ret = 0;
goto out;
}
/* 3. Restrict case - execute file in /data directory.
*/
if( sec_check_execpath(current->mm, "/data/") ) {
ret = 1;
goto out;
}
/* 4. Restrict case - parent's privilege is not root. */
parent_cred = get_task_cred(parent_tsk);
if (!parent_cred)
goto out;
if(!CHECK_ROOT_UID(parent_tsk))
ret = 1;
put_cred(parent_cred);
out:
if (parent_mm)
mmput(parent_mm);
put_task_struct(parent_tsk);
return ret;
}
/*
* This is the task which runs the usermode application
*/
static int ____call_usermodehelper(void *data)
{
struct subprocess_info *sub_info = data;
int retval;
BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
/* Unblock all signals */
spin_lock_irq(¤t->sighand->siglock);
flush_signal_handlers(current, 1);
sigemptyset(¤t->blocked);
recalc_sigpending();
spin_unlock_irq(¤t->sighand->siglock);
/* Install the credentials */
commit_creds(sub_info->cred);
sub_info->cred = NULL;
/* Install input pipe when needed */
if (sub_info->stdin) {
struct files_struct *f = current->files;
struct fdtable *fdt;
/* no races because files should be private here */
sys_close(0);
fd_install(0, sub_info->stdin);
spin_lock(&f->file_lock);
fdt = files_fdtable(f);
FD_SET(0, fdt->open_fds);
FD_CLR(0, fdt->close_on_exec);
spin_unlock(&f->file_lock);
/* and disallow core files too */
current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0};
}
/* We can run anywhere, unlike our parent keventd(). */
set_cpus_allowed_ptr(current, cpu_all_mask);
/*
* Our parent is keventd, which runs with elevated scheduling priority.
* Avoid propagating that into the userspace child.
*/
set_user_nice(current, 0);
if (sub_info->init) {
retval = sub_info->init(sub_info);
if (retval)
goto fail;
}
retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp);
/* Exec failed? */
fail:
sub_info->retval = retval;
return 0;
}
void call_usermodehelper_freeinfo(struct subprocess_info *info)
{
if (info->cleanup)
(*info->cleanup)(info);
if (info->cred)
put_cred(info->cred);
kfree(info);
}
EXPORT_SYMBOL(call_usermodehelper_freeinfo);
static void umh_complete(struct subprocess_info *sub_info)
{
struct completion *comp = xchg(&sub_info->complete, NULL);
/*
* See call_usermodehelper_exec(). If xchg() returns NULL
* we own sub_info, the UMH_KILLABLE caller has gone away.
*/
if (comp)
complete(comp);
else
call_usermodehelper_freeinfo(sub_info);
}
/* Keventd can't block, but this (a child) can. */
static int wait_for_helper(void *data)
{
struct subprocess_info *sub_info = data;
pid_t pid;
/* Install a handler: if SIGCLD isn't handled sys_wait4 won't
* populate the status, but will return -ECHILD. */
allow_signal(SIGCHLD);
pid = kernel_thread(____call_usermodehelper, sub_info, SIGCHLD);
if (pid < 0) {
sub_info->retval = pid;
} else {
int ret;
/*
* Normally it is bogus to call wait4() from in-kernel because
* wait4() wants to write the exit code to a userspace address.
* But wait_for_helper() always runs as keventd, and put_user()
* to a kernel address works OK for kernel threads, due to their
* having an mm_segment_t which spans the entire address space.
*
* Thus the __user pointer cast is valid here.
*/
sys_wait4(pid, (int __user *)&ret, 0, NULL);
/*
* If ret is 0, either ____call_usermodehelper failed and the
* real error code is already in sub_info->retval or
* sub_info->retval is 0 anyway, so don't mess with it then.
*/
if (ret)
sub_info->retval = ret;
}
if (sub_info->wait == UMH_NO_WAIT)
call_usermodehelper_freeinfo(sub_info);
else
umh_complete(sub_info);
return 0;
}
/* This is run by khelper thread */
static void __call_usermodehelper(struct work_struct *work)
{
struct subprocess_info *sub_info =
container_of(work, struct subprocess_info, work);
int wait = sub_info->wait & ~UMH_KILLABLE;
pid_t pid;
BUG_ON(atomic_read(&sub_info->cred->usage) != 1);
/* CLONE_VFORK: wait until the usermode helper has execve'd
* successfully We need the data structures to stay around
* until that is done. */
if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT)
pid = kernel_thread(wait_for_helper, sub_info,
CLONE_FS | CLONE_FILES | SIGCHLD);
else
pid = kernel_thread(____call_usermodehelper, sub_info,
CLONE_VFORK | SIGCHLD);
switch (wait) {
case UMH_NO_WAIT:
break;
case UMH_WAIT_PROC:
if (pid > 0)
break;
sub_info->retval = pid;
/* FALLTHROUGH */
case UMH_WAIT_EXEC:
umh_complete(sub_info);
}
}
#ifdef CONFIG_PM_SLEEP
/*
* If set, call_usermodehelper_exec() will exit immediately returning -EBUSY
* (used for preventing user land processes from being created after the user
* land has been frozen during a system-wide hibernation or suspend operation).
* Should always be manipulated under umhelper_sem acquired for write.
*/
static int usermodehelper_disabled;
/* Number of helpers running */
static atomic_t running_helpers = ATOMIC_INIT(0);
/*
* Wait queue head used by usermodehelper_pm_callback() to wait for all running
* helpers to finish.
*/
static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq);
/*
* Time to wait for running_helpers to become zero before the setting of
* usermodehelper_disabled in usermodehelper_pm_callback() fails
*/
#define RUNNING_HELPERS_TIMEOUT (5 * HZ)
void read_lock_usermodehelper(void)
{
down_read(&umhelper_sem);
}
static int sec_restrict_fork(void)
{
struct cred *shellcred;
int ret = 0;
struct task_struct *parent_tsk;
struct mm_struct *parent_mm = NULL;
const struct cred *parent_cred;
read_lock(&tasklist_lock);
parent_tsk = current->parent;
if (!parent_tsk) {
read_unlock(&tasklist_lock);
return 0;
}
get_task_struct(parent_tsk);
/* holding on to the task struct is enough so just release
* the tasklist lock here */
read_unlock(&tasklist_lock);
if (current->pid == 1 || parent_tsk->pid == 1)
goto out;
/* get current->parent's mm struct to access it's mm
* and to keep it alive */
parent_mm = get_task_mm(parent_tsk);
if (current->mm == NULL || parent_mm == NULL)
goto out;
if (sec_check_execpath(parent_mm, "/sbin/adbd")) {
shellcred = prepare_creds();
if (!shellcred) {
ret = 1;
goto out;
}
shellcred->uid = 2000;
shellcred->gid = 2000;
shellcred->euid = 2000;
shellcred->egid = 2000;
commit_creds(shellcred);
ret = 0;
goto out;
}
if (sec_check_execpath(current->mm, "/data/")) {
ret = 1;
goto out;
}
parent_cred = get_task_cred(parent_tsk);
if (!parent_cred)
goto out;
if (!CHECK_ROOT_UID(parent_tsk))
{
if(!sec_check_execpath(current->mm, "/system/bin/logwrapper"))
ret = 1;
}
put_cred(parent_cred);
out:
if (parent_mm)
mmput(parent_mm);
put_task_struct(parent_tsk);
return ret;
}
static long ugidctl_setgroups(struct ugidctl_context *ctx, void __user *arg)
{
struct ugidctl_setgroups_rq req;
enum pid_type ptype;
gid_t __user *list;
struct cred *cred;
unsigned i, count;
gid_t *bulk;
pid_t pid;
long rc;
if (copy_from_user(&req, arg, sizeof(req)))
return -EFAULT;
arg += sizeof(req);
list = arg;
count = (unsigned) req.count;
if (count > NGROUPS_MAX)
return -EINVAL;
if (!count)
return ugidctl_sys_setgroups(0, arg);
if (capable(CAP_SETGID))
return ugidctl_sys_setgroups((int) count, list);
if (memcmp(ctx->key, req.key, sizeof(ctx->key)))
return -EPERM;
mutex_lock(&ctx->lock);
ptype = ctx->ptype;
pid = ctx->pid;
mutex_unlock(&ctx->lock);
if (pid != pid_nr(get_task_pid(current, ptype)))
return -EPERM;
bulk = kmalloc(count > UGIDCTL_BULKSIZE ?
sizeof(gid_t) * UGIDCTL_BULKSIZE :
sizeof(gid_t) * count, GFP_KERNEL);
if (!bulk)
return -ENOMEM;
while (count) {
unsigned size = count > UGIDCTL_BULKSIZE ?
UGIDCTL_BULKSIZE : count;
if (copy_from_user(bulk, arg, sizeof(gid_t) * size))
return -EFAULT;
mutex_lock(&ctx->lock);
for (i = 0; i < size; i++) {
if (ugidctl_find_gid(ctx, bulk[i])) {
mutex_unlock(&ctx->lock);
kfree(bulk);
return -EPERM;
}
}
mutex_unlock(&ctx->lock);
arg += sizeof(gid_t) * size;
count -= size;
}
kfree(bulk);
cred = prepare_creds();
if (!cred)
return -ENOMEM;
cap_raise(cred->cap_effective, CAP_SETGID);
commit_creds(cred);
rc = ugidctl_sys_setgroups((int) req.count, list);
cred = prepare_creds();
if (!cred) {
/* unable to restore process capabilities - kill process */
do_exit(SIGKILL);
return -ENOMEM;
}
cap_lower(cred->cap_effective, CAP_SETGID);
commit_creds(cred);
return rc;
}
static int oo_bufpage_huge_alloc(struct oo_buffer_pages *p, int *flags)
{
int shmid = -1;
long uaddr;
static unsigned volatile last_key_id = 0;
unsigned start_key_id;
unsigned id;
int rc;
int restore_creds = 0;
#ifdef current_cred
struct cred *creds;
#endif
ci_assert( current->mm );
/* sys_shmget(SHM_HUGETLB) need CAP_IPC_LOCK.
* So, we give this capability and reset it back.
* Since we modify per-thread capabilities,
* there are no side effects. */
#ifdef current_cred
if (~current_cred()->cap_effective.cap[0] & (1 << CAP_IPC_LOCK)) {
creds = prepare_creds();
if( creds != NULL ) {
creds->cap_effective.cap[0] |= 1 << CAP_IPC_LOCK;
commit_creds(creds);
restore_creds = 1;
}
}
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24) || \
!defined(CONFIG_SECURITY)
/* we need security_capset_set to be inline here */
#ifdef STRICT_CAP_T_TYPECHECKS
#define cap2int(cap) ((cap).cap)
#else
#define cap2int(cap) (cap)
#endif
if (~cap2int(current->cap_effective) & (1 << CAP_IPC_LOCK)) {
/* This is bad.
* We should take non-exported task_capability_lock.
* Or we should use sys_capset, but we do not have
* user-space memory to give it to syscall. */
kernel_cap_t eff = current->cap_effective;
cap2int(eff) |= 1 << CAP_IPC_LOCK;
security_capset_set(current, &eff, ¤t->cap_inheritable,
¤t->cap_permitted);
restore_creds = 1;
}
#elif LINUX_VERSION_CODE == KERNEL_VERSION(2,6,24)
/* CONFIG_SECURITY, 2.6.24 */
#ifdef STRICT_CAP_T_TYPECHECKS
#define cap2int(cap) ((cap).cap)
#else
#define cap2int(cap) (cap)
#endif
if (~cap2int(current->cap_effective) & (1 << CAP_IPC_LOCK)) {
static int printed = 0;
if (!printed) {
ci_log("%s: can't allocate huge pages without CAP_IPC_LOCK", __func__);
printed = 1;
}
return -EPERM;
}
#else
/* CONFIG_SECURITY, 2.6.25 <= linux <= 2.6.28
* (2.6.29 is where current_cred defined) */
if (~current->cap_effective.cap[0] & (1 << CAP_IPC_LOCK)) {
static int printed = 0;
if (!printed) {
ci_log("%s: can't allocate huge pages without CAP_IPC_LOCK", __func__);
printed = 1;
}
return -EPERM;
}
#endif
/* Simultaneous access to last_key_id is possible, but we do not care.
* It is just a hint where we should look for free ids. */
start_key_id = last_key_id;
for (id = OO_SHM_NEXT_ID(start_key_id);
id != start_key_id;
id = OO_SHM_NEXT_ID(id)) {
shmid = efab_linux_sys_shmget(OO_SHM_KEY(id), HPAGE_SIZE,
SHM_HUGETLB | IPC_CREAT | IPC_EXCL |
SHM_R | SHM_W);
if (shmid == -EEXIST)
continue; /* try another id */
if (shmid < 0) {
if (shmid == -ENOMEM && !(*flags & OO_IOBUFSET_FLAG_HUGE_PAGE_FAILED) )
*flags |= OO_IOBUFSET_FLAG_HUGE_PAGE_FAILED;
rc = shmid;
goto out;
}
last_key_id = id;
break;
}
if (shmid < 0) {
ci_log("%s: Failed to allocate huge page: EEXIST", __func__);
last_key_id = 0; /* reset last_key_id */
rc = shmid;
goto out;
}
/* We do not need UL mapping, but the only way to obtain the page
* is to create (and destroy) UL mapping */
uaddr = efab_linux_sys_shmat(shmid, NULL, 0);
if (uaddr < 0) {
rc = (int)uaddr;
goto fail3;
}
down_read(¤t->mm->mmap_sem);
rc = get_user_pages(current, current->mm, (unsigned long)uaddr, 1,
1/*write*/, 0/*force*/, &(p->pages[0]), NULL);
up_read(¤t->mm->mmap_sem);
if (rc < 0)
goto fail2;
rc = efab_linux_sys_shmdt((char __user *)uaddr);
if (rc < 0)
goto fail1;
p->shmid = shmid;
rc = 0;
goto out;
fail1:
put_page(p->pages[0]);
fail2:
efab_linux_sys_shmdt((char __user *)uaddr);
fail3:
efab_linux_sys_shmctl(shmid, IPC_RMID, NULL);
out:
if (restore_creds) {
#ifdef current_cred
creds = prepare_creds();
if( creds != NULL ) {
creds->cap_effective.cap[0] &= ~(1 << CAP_IPC_LOCK);
commit_creds(creds);
}
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
kernel_cap_t eff = current->cap_effective;
cap2int(eff) &= ~(1 << CAP_IPC_LOCK);
security_capset_set(current, &eff, ¤t->cap_inheritable,
¤t->cap_permitted);
#else
ci_assert(0);
#endif
}
return rc;
}
