#endif
#ifdef CONFIG_SECCOMP_FILTER
+#include <linux/file.h>
#include <linux/filter.h>
#include <linux/pid.h>
#include <linux/ptrace.h>
#include <linux/security.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>
+#include <linux/anon_inodes.h>
+
+enum notify_state {
+ SECCOMP_NOTIFY_INIT,
+ SECCOMP_NOTIFY_SENT,
+ SECCOMP_NOTIFY_REPLIED,
+};
+
+struct seccomp_knotif {
+ /* The struct pid of the task whose filter triggered the notification */
+ struct task_struct *task;
+
+ /* The "cookie" for this request; this is unique for this filter. */
+ u64 id;
+
+ /*
+ * The seccomp data. This pointer is valid the entire time this
+ * notification is active, since it comes from __seccomp_filter which
+ * eclipses the entire lifecycle here.
+ */
+ const struct seccomp_data *data;
+
+ /*
+ * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a
+ * struct seccomp_knotif is created and starts out in INIT. Once the
+ * handler reads the notification off of an FD, it transitions to SENT.
+ * If a signal is received the state transitions back to INIT and
+ * another message is sent. When the userspace handler replies, state
+ * transitions to REPLIED.
+ */
+ enum notify_state state;
+
+ /* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */
+ int error;
+ long val;
+
+ /* Signals when this has entered SECCOMP_NOTIFY_REPLIED */
+ struct completion ready;
+
+ struct list_head list;
+};
+
+/**
+ * struct notification - container for seccomp userspace notifications. Since
+ * most seccomp filters will not have notification listeners attached and this
+ * structure is fairly large, we store the notification-specific stuff in a
+ * separate structure.
+ *
+ * @request: A semaphore that users of this notification can wait on for
+ * changes. Actual reads and writes are still controlled with
+ * filter->notify_lock.
+ * @next_id: The id of the next request.
+ * @notifications: A list of struct seccomp_knotif elements.
+ * @wqh: A wait queue for poll.
+ */
+struct notification {
+ struct semaphore request;
+ u64 next_id;
+ struct list_head notifications;
+ wait_queue_head_t wqh;
+};
/**
* struct seccomp_filter - container for seccomp BPF programs
* @log: true if all actions except for SECCOMP_RET_ALLOW should be logged
* @prev: points to a previously installed, or inherited, filter
* @prog: the BPF program to evaluate
+ * @notif: the struct that holds all notification related information
+ * @notify_lock: A lock for all notification-related accesses.
*
* seccomp_filter objects are organized in a tree linked via the @prev
* pointer. For any task, it appears to be a singly-linked list starting
bool log;
struct seccomp_filter *prev;
struct bpf_prog *prog;
+ struct notification *notif;
+ struct mutex notify_lock;
};
/* Limit any path through the tree to 256KB worth of instructions. */
if (!sfilter)
return ERR_PTR(-ENOMEM);
+ mutex_init(&sfilter->notify_lock);
ret = bpf_prog_create_from_user(&sfilter->prog, fprog,
seccomp_check_filter, save_orig);
if (ret < 0) {
static void __get_seccomp_filter(struct seccomp_filter *filter)
{
- /* Reference count is bounded by the number of total processes. */
refcount_inc(&filter->usage);
}
#define SECCOMP_LOG_TRACE (1 << 4)
#define SECCOMP_LOG_LOG (1 << 5)
#define SECCOMP_LOG_ALLOW (1 << 6)
+#define SECCOMP_LOG_USER_NOTIF (1 << 7)
static u32 seccomp_actions_logged = SECCOMP_LOG_KILL_PROCESS |
SECCOMP_LOG_KILL_THREAD |
SECCOMP_LOG_TRAP |
SECCOMP_LOG_ERRNO |
+ SECCOMP_LOG_USER_NOTIF |
SECCOMP_LOG_TRACE |
SECCOMP_LOG_LOG;
case SECCOMP_RET_TRACE:
log = requested && seccomp_actions_logged & SECCOMP_LOG_TRACE;
break;
+ case SECCOMP_RET_USER_NOTIF:
+ log = requested && seccomp_actions_logged & SECCOMP_LOG_USER_NOTIF;
+ break;
case SECCOMP_RET_LOG:
log = seccomp_actions_logged & SECCOMP_LOG_LOG;
break;
#else
#ifdef CONFIG_SECCOMP_FILTER
+static u64 seccomp_next_notify_id(struct seccomp_filter *filter)
+{
+ /*
+ * Note: overflow is ok here, the id just needs to be unique per
+ * filter.
+ */
+ lockdep_assert_held(&filter->notify_lock);
+ return filter->notif->next_id++;
+}
+
+static void seccomp_do_user_notification(int this_syscall,
+ struct seccomp_filter *match,
+ const struct seccomp_data *sd)
+{
+ int err;
+ long ret = 0;
+ struct seccomp_knotif n = {};
+
+ mutex_lock(&match->notify_lock);
+ err = -ENOSYS;
+ if (!match->notif)
+ goto out;
+
+ n.task = current;
+ n.state = SECCOMP_NOTIFY_INIT;
+ n.data = sd;
+ n.id = seccomp_next_notify_id(match);
+ init_completion(&n.ready);
+ list_add(&n.list, &match->notif->notifications);
+
+ up(&match->notif->request);
+ wake_up_poll(&match->notif->wqh, EPOLLIN | EPOLLRDNORM);
+ mutex_unlock(&match->notify_lock);
+
+ /*
+ * This is where we wait for a reply from userspace.
+ */
+ err = wait_for_completion_interruptible(&n.ready);
+ mutex_lock(&match->notify_lock);
+ if (err == 0) {
+ ret = n.val;
+ err = n.error;
+ }
+
+ /*
+ * Note that it's possible the listener died in between the time when
+ * we were notified of a respons (or a signal) and when we were able to
+ * re-acquire the lock, so only delete from the list if the
+ * notification actually exists.
+ *
+ * Also note that this test is only valid because there's no way to
+ * *reattach* to a notifier right now. If one is added, we'll need to
+ * keep track of the notif itself and make sure they match here.
+ */
+ if (match->notif)
+ list_del(&n.list);
+out:
+ mutex_unlock(&match->notify_lock);
+ syscall_set_return_value(current, task_pt_regs(current),
+ err, ret);
+}
+
static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
const bool recheck_after_trace)
{
return 0;
+ case SECCOMP_RET_USER_NOTIF:
+ seccomp_do_user_notification(this_syscall, match, sd);
+ goto skip;
+
case SECCOMP_RET_LOG:
seccomp_log(this_syscall, 0, action, true);
return 0;
}
#ifdef CONFIG_SECCOMP_FILTER
+static int seccomp_notify_release(struct inode *inode, struct file *file)
+{
+ struct seccomp_filter *filter = file->private_data;
+ struct seccomp_knotif *knotif;
+
+ mutex_lock(&filter->notify_lock);
+
+ /*
+ * If this file is being closed because e.g. the task who owned it
+ * died, let's wake everyone up who was waiting on us.
+ */
+ list_for_each_entry(knotif, &filter->notif->notifications, list) {
+ if (knotif->state == SECCOMP_NOTIFY_REPLIED)
+ continue;
+
+ knotif->state = SECCOMP_NOTIFY_REPLIED;
+ knotif->error = -ENOSYS;
+ knotif->val = 0;
+
+ complete(&knotif->ready);
+ }
+
+ kfree(filter->notif);
+ filter->notif = NULL;
+ mutex_unlock(&filter->notify_lock);
+ __put_seccomp_filter(filter);
+ return 0;
+}
+
+static long seccomp_notify_recv(struct seccomp_filter *filter,
+ void __user *buf)
+{
+ struct seccomp_knotif *knotif = NULL, *cur;
+ struct seccomp_notif unotif;
+ ssize_t ret;
+
+ memset(&unotif, 0, sizeof(unotif));
+
+ ret = down_interruptible(&filter->notif->request);
+ if (ret < 0)
+ return ret;
+
+ mutex_lock(&filter->notify_lock);
+ list_for_each_entry(cur, &filter->notif->notifications, list) {
+ if (cur->state == SECCOMP_NOTIFY_INIT) {
+ knotif = cur;
+ break;
+ }
+ }
+
+ /*
+ * If we didn't find a notification, it could be that the task was
+ * interrupted by a fatal signal between the time we were woken and
+ * when we were able to acquire the rw lock.
+ */
+ if (!knotif) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ unotif.id = knotif->id;
+ unotif.pid = task_pid_vnr(knotif->task);
+ unotif.data = *(knotif->data);
+
+ knotif->state = SECCOMP_NOTIFY_SENT;
+ wake_up_poll(&filter->notif->wqh, EPOLLOUT | EPOLLWRNORM);
+ ret = 0;
+out:
+ mutex_unlock(&filter->notify_lock);
+
+ if (ret == 0 && copy_to_user(buf, &unotif, sizeof(unotif))) {
+ ret = -EFAULT;
+
+ /*
+ * Userspace screwed up. To make sure that we keep this
+ * notification alive, let's reset it back to INIT. It
+ * may have died when we released the lock, so we need to make
+ * sure it's still around.
+ */
+ knotif = NULL;
+ mutex_lock(&filter->notify_lock);
+ list_for_each_entry(cur, &filter->notif->notifications, list) {
+ if (cur->id == unotif.id) {
+ knotif = cur;
+ break;
+ }
+ }
+
+ if (knotif) {
+ knotif->state = SECCOMP_NOTIFY_INIT;
+ up(&filter->notif->request);
+ }
+ mutex_unlock(&filter->notify_lock);
+ }
+
+ return ret;
+}
+
+static long seccomp_notify_send(struct seccomp_filter *filter,
+ void __user *buf)
+{
+ struct seccomp_notif_resp resp = {};
+ struct seccomp_knotif *knotif = NULL, *cur;
+ long ret;
+
+ if (copy_from_user(&resp, buf, sizeof(resp)))
+ return -EFAULT;
+
+ if (resp.flags)
+ return -EINVAL;
+
+ ret = mutex_lock_interruptible(&filter->notify_lock);
+ if (ret < 0)
+ return ret;
+
+ list_for_each_entry(cur, &filter->notif->notifications, list) {
+ if (cur->id == resp.id) {
+ knotif = cur;
+ break;
+ }
+ }
+
+ if (!knotif) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ /* Allow exactly one reply. */
+ if (knotif->state != SECCOMP_NOTIFY_SENT) {
+ ret = -EINPROGRESS;
+ goto out;
+ }
+
+ ret = 0;
+ knotif->state = SECCOMP_NOTIFY_REPLIED;
+ knotif->error = resp.error;
+ knotif->val = resp.val;
+ complete(&knotif->ready);
+out:
+ mutex_unlock(&filter->notify_lock);
+ return ret;
+}
+
+static long seccomp_notify_id_valid(struct seccomp_filter *filter,
+ void __user *buf)
+{
+ struct seccomp_knotif *knotif = NULL;
+ u64 id;
+ long ret;
+
+ if (copy_from_user(&id, buf, sizeof(id)))
+ return -EFAULT;
+
+ ret = mutex_lock_interruptible(&filter->notify_lock);
+ if (ret < 0)
+ return ret;
+
+ ret = -ENOENT;
+ list_for_each_entry(knotif, &filter->notif->notifications, list) {
+ if (knotif->id == id) {
+ if (knotif->state == SECCOMP_NOTIFY_SENT)
+ ret = 0;
+ goto out;
+ }
+ }
+
+out:
+ mutex_unlock(&filter->notify_lock);
+ return ret;
+}
+
+static long seccomp_notify_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct seccomp_filter *filter = file->private_data;
+ void __user *buf = (void __user *)arg;
+
+ switch (cmd) {
+ case SECCOMP_IOCTL_NOTIF_RECV:
+ return seccomp_notify_recv(filter, buf);
+ case SECCOMP_IOCTL_NOTIF_SEND:
+ return seccomp_notify_send(filter, buf);
+ case SECCOMP_IOCTL_NOTIF_ID_VALID:
+ return seccomp_notify_id_valid(filter, buf);
+ default:
+ return -EINVAL;
+ }
+}
+
+static __poll_t seccomp_notify_poll(struct file *file,
+ struct poll_table_struct *poll_tab)
+{
+ struct seccomp_filter *filter = file->private_data;
+ __poll_t ret = 0;
+ struct seccomp_knotif *cur;
+
+ poll_wait(file, &filter->notif->wqh, poll_tab);
+
+ ret = mutex_lock_interruptible(&filter->notify_lock);
+ if (ret < 0)
+ return EPOLLERR;
+
+ list_for_each_entry(cur, &filter->notif->notifications, list) {
+ if (cur->state == SECCOMP_NOTIFY_INIT)
+ ret |= EPOLLIN | EPOLLRDNORM;
+ if (cur->state == SECCOMP_NOTIFY_SENT)
+ ret |= EPOLLOUT | EPOLLWRNORM;
+ if ((ret & EPOLLIN) && (ret & EPOLLOUT))
+ break;
+ }
+
+ mutex_unlock(&filter->notify_lock);
+
+ return ret;
+}
+
+static const struct file_operations seccomp_notify_ops = {
+ .poll = seccomp_notify_poll,
+ .release = seccomp_notify_release,
+ .unlocked_ioctl = seccomp_notify_ioctl,
+};
+
+static struct file *init_listener(struct seccomp_filter *filter)
+{
+ struct file *ret = ERR_PTR(-EBUSY);
+ struct seccomp_filter *cur;
+
+ for (cur = current->seccomp.filter; cur; cur = cur->prev) {
+ if (cur->notif)
+ goto out;
+ }
+
+ ret = ERR_PTR(-ENOMEM);
+ filter->notif = kzalloc(sizeof(*(filter->notif)), GFP_KERNEL);
+ if (!filter->notif)
+ goto out;
+
+ sema_init(&filter->notif->request, 0);
+ filter->notif->next_id = get_random_u64();
+ INIT_LIST_HEAD(&filter->notif->notifications);
+ init_waitqueue_head(&filter->notif->wqh);
+
+ ret = anon_inode_getfile("seccomp notify", &seccomp_notify_ops,
+ filter, O_RDWR);
+ if (IS_ERR(ret))
+ goto out_notif;
+
+ /* The file has a reference to it now */
+ __get_seccomp_filter(filter);
+
+out_notif:
+ if (IS_ERR(ret))
+ kfree(filter->notif);
+out:
+ return ret;
+}
+
/**
* seccomp_set_mode_filter: internal function for setting seccomp filter
* @flags: flags to change filter behavior
const unsigned long seccomp_mode = SECCOMP_MODE_FILTER;
struct seccomp_filter *prepared = NULL;
long ret = -EINVAL;
+ int listener = -1;
+ struct file *listener_f = NULL;
/* Validate flags. */
if (flags & ~SECCOMP_FILTER_FLAG_MASK)
if (IS_ERR(prepared))
return PTR_ERR(prepared);
+ if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
+ listener = get_unused_fd_flags(O_CLOEXEC);
+ if (listener < 0) {
+ ret = listener;
+ goto out_free;
+ }
+
+ listener_f = init_listener(prepared);
+ if (IS_ERR(listener_f)) {
+ put_unused_fd(listener);
+ ret = PTR_ERR(listener_f);
+ goto out_free;
+ }
+ }
+
/*
* Make sure we cannot change seccomp or nnp state via TSYNC
* while another thread is in the middle of calling exec.
*/
if (flags & SECCOMP_FILTER_FLAG_TSYNC &&
mutex_lock_killable(¤t->signal->cred_guard_mutex))
- goto out_free;
+ goto out_put_fd;
spin_lock_irq(¤t->sighand->siglock);
spin_unlock_irq(¤t->sighand->siglock);
if (flags & SECCOMP_FILTER_FLAG_TSYNC)
mutex_unlock(¤t->signal->cred_guard_mutex);
+out_put_fd:
+ if (flags & SECCOMP_FILTER_FLAG_NEW_LISTENER) {
+ if (ret < 0) {
+ fput(listener_f);
+ put_unused_fd(listener);
+ } else {
+ fd_install(listener, listener_f);
+ ret = listener;
+ }
+ }
out_free:
seccomp_filter_free(prepared);
return ret;
case SECCOMP_RET_KILL_THREAD:
case SECCOMP_RET_TRAP:
case SECCOMP_RET_ERRNO:
+ case SECCOMP_RET_USER_NOTIF:
case SECCOMP_RET_TRACE:
case SECCOMP_RET_LOG:
case SECCOMP_RET_ALLOW:
return 0;
}
+static long seccomp_get_notif_sizes(void __user *usizes)
+{
+ struct seccomp_notif_sizes sizes = {
+ .seccomp_notif = sizeof(struct seccomp_notif),
+ .seccomp_notif_resp = sizeof(struct seccomp_notif_resp),
+ .seccomp_data = sizeof(struct seccomp_data),
+ };
+
+ if (copy_to_user(usizes, &sizes, sizeof(sizes)))
+ return -EFAULT;
+
+ return 0;
+}
+
/* Common entry point for both prctl and syscall. */
static long do_seccomp(unsigned int op, unsigned int flags,
void __user *uargs)
return -EINVAL;
return seccomp_get_action_avail(uargs);
+ case SECCOMP_GET_NOTIF_SIZES:
+ if (flags != 0)
+ return -EINVAL;
+
+ return seccomp_get_notif_sizes(uargs);
default:
return -EINVAL;
}
#define SECCOMP_RET_KILL_THREAD_NAME "kill_thread"
#define SECCOMP_RET_TRAP_NAME "trap"
#define SECCOMP_RET_ERRNO_NAME "errno"
+#define SECCOMP_RET_USER_NOTIF_NAME "user_notif"
#define SECCOMP_RET_TRACE_NAME "trace"
#define SECCOMP_RET_LOG_NAME "log"
#define SECCOMP_RET_ALLOW_NAME "allow"
SECCOMP_RET_KILL_THREAD_NAME " "
SECCOMP_RET_TRAP_NAME " "
SECCOMP_RET_ERRNO_NAME " "
+ SECCOMP_RET_USER_NOTIF_NAME " "
SECCOMP_RET_TRACE_NAME " "
SECCOMP_RET_LOG_NAME " "
SECCOMP_RET_ALLOW_NAME;
{ SECCOMP_LOG_KILL_THREAD, SECCOMP_RET_KILL_THREAD_NAME },
{ SECCOMP_LOG_TRAP, SECCOMP_RET_TRAP_NAME },
{ SECCOMP_LOG_ERRNO, SECCOMP_RET_ERRNO_NAME },
+ { SECCOMP_LOG_USER_NOTIF, SECCOMP_RET_USER_NOTIF_NAME },
{ SECCOMP_LOG_TRACE, SECCOMP_RET_TRACE_NAME },
{ SECCOMP_LOG_LOG, SECCOMP_RET_LOG_NAME },
{ SECCOMP_LOG_ALLOW, SECCOMP_RET_ALLOW_NAME },
projects / linux-2.6-microblaze.git / blobdiff