Commit message: do_sigaltstack: avoid copying 'stack_t' as a structure to user space

Ulrich Drepper correctly points out that there is generally padding in
the structure on 64-bit hosts, and that copying the structure from
kernel to user space can leak information from the kernel stack in those
padding bytes.

Avoid the whole issue by just copying the three members one by one
instead, which also means that the function also can avoid the need for
a stack frame.  This also happens to match how we copy the new structure
from user space, so it all even makes sense.

[ The obvious solution of adding a memset() generates horrid code, gcc
  does really stupid things. ]

Reported-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CVE: CVE-2009-2847
CWE: NVD-CWE-noinfo
Vulnerability description: The do_sigaltstack function in kernel/signal.c in Linux kernel 2.4 through 2.4.37 and 2.6 before 2.6.31-rc5, when running on 64-bit systems, does not clear certain padding bytes from a structure, which allows local users to obtain sensitive information from the kernel stack via the sigaltstack function.

Project: linux-2.6

void signal_wake_up(struct task_struct *t, int resume)
{
	unsigned int mask;

	set_tsk_thread_flag(t, TIF_SIGPENDING);

	/*
	 * For SIGKILL, we want to wake it up in the stopped/traced/killable
	 * case. We don't check t->state here because there is a race with it
	 * executing another processor and just now entering stopped state.
	 * By using wake_up_state, we ensure the process will wake up and
	 * handle its death signal.
	 */
	mask = TASK_INTERRUPTIBLE;
	if (resume)
		mask |= TASK_WAKEKILL;
	if (!wake_up_state(t, mask))
		kick_process(t);
}

Project: linux-2.6

int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
	unsigned long flags;
	int ret;

	ret = check_kill_permission(sig, info, p);

	if (!ret && sig) {
		ret = -ESRCH;
		if (lock_task_sighand(p, &flags)) {
			ret = __group_send_sig_info(sig, info, p);
			unlock_task_sighand(p, &flags);
		}
	}

	return ret;
}

Project: linux-2.6

static int sig_task_ignored(struct task_struct *t, int sig,
		int from_ancestor_ns)
{
	void __user *handler;

	handler = sig_handler(t, sig);

	if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
			handler == SIG_DFL && !from_ancestor_ns)
		return 1;

	return sig_handler_ignored(handler, sig);
}

Project: linux-2.6

void ptrace_notify(int exit_code)
{
	siginfo_t info;

	BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);

	memset(&info, 0, sizeof info);
	info.si_signo = SIGTRAP;
	info.si_code = exit_code;
	info.si_pid = task_pid_vnr(current);
	info.si_uid = current_uid();

	/* Let the debugger run.  */
	spin_lock_irq(&current->sighand->siglock);
	ptrace_stop(exit_code, 1, &info);
	spin_unlock_irq(&current->sighand->siglock);
}

Project: linux-2.6

do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
{
	struct task_struct *p;
	unsigned long flags;
	int error = -ESRCH;

	rcu_read_lock();
	p = find_task_by_vpid(pid);
	if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) {
		error = check_kill_permission(sig, info, p);
		/*
		 * The null signal is a permissions and process existence
		 * probe.  No signal is actually delivered.
		 *
		 * If lock_task_sighand() fails we pretend the task dies
		 * after receiving the signal. The window is tiny, and the
		 * signal is private anyway.
		 */
		if (!error && sig && lock_task_sighand(p, &flags)) {
			error = specific_send_sig_info(sig, info, p);
			unlock_task_sighand(p, &flags);
		}
	}
	rcu_read_unlock();

	return error;
}

Project: linux-2.6

SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
		siginfo_t __user *, uinfo, const struct timespec __user *, uts,
		size_t, sigsetsize)
{
	int ret, sig;
	sigset_t these;
	struct timespec ts;
	siginfo_t info;
	long timeout = 0;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&these, uthese, sizeof(these)))
		return -EFAULT;
		
	/*
	 * Invert the set of allowed signals to get those we
	 * want to block.
	 */
	sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP));
	signotset(&these);

	if (uts) {
		if (copy_from_user(&ts, uts, sizeof(ts)))
			return -EFAULT;
		if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0
		    || ts.tv_sec < 0)
			return -EINVAL;
	}

	spin_lock_irq(&current->sighand->siglock);
	sig = dequeue_signal(current, &these, &info);
	if (!sig) {
		timeout = MAX_SCHEDULE_TIMEOUT;
		if (uts)
			timeout = (timespec_to_jiffies(&ts)
				   + (ts.tv_sec || ts.tv_nsec));

		if (timeout) {
			/* None ready -- temporarily unblock those we're
			 * interested while we are sleeping in so that we'll
			 * be awakened when they arrive.  */
			current->real_blocked = current->blocked;
			sigandsets(&current->blocked, &current->blocked, &these);
			recalc_sigpending();
			spin_unlock_irq(&current->sighand->siglock);

			timeout = schedule_timeout_interruptible(timeout);

			spin_lock_irq(&current->sighand->siglock);
			sig = dequeue_signal(current, &these, &info);
			current->blocked = current->real_blocked;
			siginitset(&current->real_blocked, 0);
			recalc_sigpending();
		}
	}
	spin_unlock_irq(&current->sighand->siglock);

	if (sig) {
		ret = sig;
		if (uinfo) {
			if (copy_siginfo_to_user(uinfo, &info))
				ret = -EFAULT;
		}
	} else {
		ret = -EAGAIN;
		if (timeout)
			ret = -EINTR;
	}

	return ret;
}

Project: linux-2.6

SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
		sigset_t __user *, oset, size_t, sigsetsize)
{
	int error = -EINVAL;
	sigset_t old_set, new_set;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		goto out;

	if (set) {
		error = -EFAULT;
		if (copy_from_user(&new_set, set, sizeof(*set)))
			goto out;
		sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));

		error = sigprocmask(how, &new_set, &old_set);
		if (error)
			goto out;
		if (oset)
			goto set_old;
	} else if (oset) {
		spin_lock_irq(&current->sighand->siglock);
		old_set = current->blocked;
		spin_unlock_irq(&current->sighand->siglock);

	set_old:
		error = -EFAULT;
		if (copy_to_user(oset, &old_set, sizeof(*oset)))
			goto out;
	}
	error = 0;
out:
	return error;
}

Project: linux-2.6

static int do_tkill(pid_t tgid, pid_t pid, int sig)
{
	struct siginfo info;

	info.si_signo = sig;
	info.si_errno = 0;
	info.si_code = SI_TKILL;
	info.si_pid = task_tgid_vnr(current);
	info.si_uid = current_uid();

	return do_send_specific(tgid, pid, sig, &info);
}

Project: linux-2.6

finish_stop(int stop_count)
{
	/*
	 * If there are no other threads in the group, or if there is
	 * a group stop in progress and we are the last to stop,
	 * report to the parent.  When ptraced, every thread reports itself.
	 */
	if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {
		read_lock(&tasklist_lock);
		do_notify_parent_cldstop(current, CLD_STOPPED);
		read_unlock(&tasklist_lock);
	}

	do {
		schedule();
	} while (try_to_freeze());
	/*
	 * Now we don't run again until continued.
	 */
	current->exit_code = 0;
}

Project: linux-2.6

do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp)
{
	stack_t oss;
	int error;

	oss.ss_sp = (void __user *) current->sas_ss_sp;
	oss.ss_size = current->sas_ss_size;
	oss.ss_flags = sas_ss_flags(sp);

	if (uss) {
		void __user *ss_sp;
		size_t ss_size;
		int ss_flags;

		error = -EFAULT;
		if (!access_ok(VERIFY_READ, uss, sizeof(*uss))
		    || __get_user(ss_sp, &uss->ss_sp)
		    || __get_user(ss_flags, &uss->ss_flags)
		    || __get_user(ss_size, &uss->ss_size))
			goto out;

		error = -EPERM;
		if (on_sig_stack(sp))
			goto out;

		error = -EINVAL;
		/*
		 *
		 * Note - this code used to test ss_flags incorrectly
		 *  	  old code may have been written using ss_flags==0
		 *	  to mean ss_flags==SS_ONSTACK (as this was the only
		 *	  way that worked) - this fix preserves that older
		 *	  mechanism
		 */
		if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
			goto out;

		if (ss_flags == SS_DISABLE) {
			ss_size = 0;
			ss_sp = NULL;
		} else {
			error = -ENOMEM;
			if (ss_size < MINSIGSTKSZ)
				goto out;
		}

		current->sas_ss_sp = (unsigned long) ss_sp;
		current->sas_ss_size = ss_size;
	}

	error = 0;
	if (uoss) {
		error = -EFAULT;
		if (!access_ok(VERIFY_WRITE, uoss, sizeof(*uoss)))
			goto out;
		error = __put_user(oss.ss_sp, &uoss->ss_sp) |
			__put_user(oss.ss_size, &uoss->ss_size) |
			__put_user(oss.ss_flags, &uoss->ss_flags);
	}

out:
	return error;
}

Project: linux-2.6

static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
{
	struct signal_struct *signal = p->signal;
	struct task_struct *t;

	if (unlikely(signal->flags & SIGNAL_GROUP_EXIT)) {
		/*
		 * The process is in the middle of dying, nothing to do.
		 */
	} else if (sig_kernel_stop(sig)) {
		/*
		 * This is a stop signal.  Remove SIGCONT from all queues.
		 */
		rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
		t = p;
		do {
			rm_from_queue(sigmask(SIGCONT), &t->pending);
		} while_each_thread(p, t);
	} else if (sig == SIGCONT) {
		unsigned int why;
		/*
		 * Remove all stop signals from all queues,
		 * and wake all threads.
		 */
		rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
		t = p;
		do {
			unsigned int state;
			rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
			/*
			 * If there is a handler for SIGCONT, we must make
			 * sure that no thread returns to user mode before
			 * we post the signal, in case it was the only
			 * thread eligible to run the signal handler--then
			 * it must not do anything between resuming and
			 * running the handler.  With the TIF_SIGPENDING
			 * flag set, the thread will pause and acquire the
			 * siglock that we hold now and until we've queued
			 * the pending signal.
			 *
			 * Wake up the stopped thread _after_ setting
			 * TIF_SIGPENDING
			 */
			state = __TASK_STOPPED;
			if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) {
				set_tsk_thread_flag(t, TIF_SIGPENDING);
				state |= TASK_INTERRUPTIBLE;
			}
			wake_up_state(t, state);
		} while_each_thread(p, t);

		/*
		 * Notify the parent with CLD_CONTINUED if we were stopped.
		 *
		 * If we were in the middle of a group stop, we pretend it
		 * was already finished, and then continued. Since SIGCHLD
		 * doesn't queue we report only CLD_STOPPED, as if the next
		 * CLD_CONTINUED was dropped.
		 */
		why = 0;
		if (signal->flags & SIGNAL_STOP_STOPPED)
			why |= SIGNAL_CLD_CONTINUED;
		else if (signal->group_stop_count)
			why |= SIGNAL_CLD_STOPPED;

		if (why) {
			/*
			 * The first thread which returns from finish_stop()
			 * will take ->siglock, notice SIGNAL_CLD_MASK, and
			 * notify its parent. See get_signal_to_deliver().
			 */
			signal->flags = why | SIGNAL_STOP_CONTINUED;
			signal->group_stop_count = 0;
			signal->group_exit_code = 0;
		} else {
			/*
			 * We are not stopped, but there could be a stop
			 * signal in the middle of being processed after
			 * being removed from the queue.  Clear that too.
			 */
			signal->flags &= ~SIGNAL_STOP_DEQUEUED;
		}
	}

	return !sig_ignored(p, sig, from_ancestor_ns);
}

Project: linux-2.6

static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
			int group, int from_ancestor_ns)
{
	struct sigpending *pending;
	struct sigqueue *q;
	int override_rlimit;

	trace_sched_signal_send(sig, t);

	assert_spin_locked(&t->sighand->siglock);

	if (!prepare_signal(sig, t, from_ancestor_ns))
		return 0;

	pending = group ? &t->signal->shared_pending : &t->pending;
	/*
	 * Short-circuit ignored signals and support queuing
	 * exactly one non-rt signal, so that we can get more
	 * detailed information about the cause of the signal.
	 */
	if (legacy_queue(pending, sig))
		return 0;
	/*
	 * fast-pathed signals for kernel-internal things like SIGSTOP
	 * or SIGKILL.
	 */
	if (info == SEND_SIG_FORCED)
		goto out_set;

	/* Real-time signals must be queued if sent by sigqueue, or
	   some other real-time mechanism.  It is implementation
	   defined whether kill() does so.  We attempt to do so, on
	   the principle of least surprise, but since kill is not
	   allowed to fail with EAGAIN when low on memory we just
	   make sure at least one signal gets delivered and don't
	   pass on the info struct.  */

	if (sig < SIGRTMIN)
		override_rlimit = (is_si_special(info) || info->si_code >= 0);
	else
		override_rlimit = 0;

	q = __sigqueue_alloc(t, GFP_ATOMIC | __GFP_NOTRACK_FALSE_POSITIVE,
		override_rlimit);
	if (q) {
		list_add_tail(&q->list, &pending->list);
		switch ((unsigned long) info) {
		case (unsigned long) SEND_SIG_NOINFO:
			q->info.si_signo = sig;
			q->info.si_errno = 0;
			q->info.si_code = SI_USER;
			q->info.si_pid = task_tgid_nr_ns(current,
							task_active_pid_ns(t));
			q->info.si_uid = current_uid();
			break;
		case (unsigned long) SEND_SIG_PRIV:
			q->info.si_signo = sig;
			q->info.si_errno = 0;
			q->info.si_code = SI_KERNEL;
			q->info.si_pid = 0;
			q->info.si_uid = 0;
			break;
		default:
			copy_siginfo(&q->info, info);
			if (from_ancestor_ns)
				q->info.si_pid = 0;
			break;
		}
	} else if (!is_si_special(info)) {
		if (sig >= SIGRTMIN && info->si_code != SI_USER)
		/*
		 * Queue overflow, abort.  We may abort if the signal was rt
		 * and sent by user using something other than kill().
		 */
			return -EAGAIN;
	}

out_set:
	signalfd_notify(t, sig);
	sigaddset(&pending->signal, sig);
	complete_signal(sig, t, group);
	return 0;
}

Project: linux-2.6

struct sigqueue *sigqueue_alloc(void)
{
	struct sigqueue *q;

	if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0)))
		q->flags |= SIGQUEUE_PREALLOC;
	return(q);
}

Project: linux-2.6

void zap_other_threads(struct task_struct *p)
{
	struct task_struct *t;

	p->signal->group_stop_count = 0;

	for (t = next_thread(p); t != p; t = next_thread(t)) {
		/*
		 * Don't bother with already dead threads
		 */
		if (t->exit_state)
			continue;

		/* SIGKILL will be handled before any pending SIGSTOP */
		sigaddset(&t->pending.signal, SIGKILL);
		signal_wake_up(t, 1);
	}
}

Project: linux-2.6

static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns)
{
	/*
	 * Blocked signals are never ignored, since the
	 * signal handler may change by the time it is
	 * unblocked.
	 */
	if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
		return 0;

	if (!sig_task_ignored(t, sig, from_ancestor_ns))
		return 0;

	/*
	 * Tracers may want to know about even ignored signals.
	 */
	return !tracehook_consider_ignored_signal(t, sig);
}

Project: linux-2.6

void exit_signals(struct task_struct *tsk)
{
	int group_stop = 0;
	struct task_struct *t;

	if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
		tsk->flags |= PF_EXITING;
		return;
	}

	spin_lock_irq(&tsk->sighand->siglock);
	/*
	 * From now this task is not visible for group-wide signals,
	 * see wants_signal(), do_signal_stop().
	 */
	tsk->flags |= PF_EXITING;
	if (!signal_pending(tsk))
		goto out;

	/* It could be that __group_complete_signal() choose us to
	 * notify about group-wide signal. Another thread should be
	 * woken now to take the signal since we will not.
	 */
	for (t = tsk; (t = next_thread(t)) != tsk; )
		if (!signal_pending(t) && !(t->flags & PF_EXITING))
			recalc_sigpending_and_wake(t);

	if (unlikely(tsk->signal->group_stop_count) &&
			!--tsk->signal->group_stop_count) {
		tsk->signal->flags = SIGNAL_STOP_STOPPED;
		group_stop = 1;
	}
out:
	spin_unlock_irq(&tsk->sighand->siglock);

	if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
		read_lock(&tasklist_lock);
		do_notify_parent_cldstop(tsk, CLD_STOPPED);
		read_unlock(&tasklist_lock);
	}
}

Project: linux-2.6

SYSCALL_DEFINE1(ssetmask, int, newmask)
{
	int old;

	spin_lock_irq(&current->sighand->siglock);
	old = current->blocked.sig[0];

	siginitset(&current->blocked, newmask & ~(sigmask(SIGKILL)|
						  sigmask(SIGSTOP)));
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	return old;
}

Project: linux-2.6

struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
{
	struct sighand_struct *sighand;

	rcu_read_lock();
	for (;;) {
		sighand = rcu_dereference(tsk->sighand);
		if (unlikely(sighand == NULL))
			break;

		spin_lock_irqsave(&sighand->siglock, *flags);
		if (likely(sighand == tsk->sighand))
			break;
		spin_unlock_irqrestore(&sighand->siglock, *flags);
	}
	rcu_read_unlock();

	return sighand;
}

Project: linux-2.6

int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
{
	int sig = q->info.si_signo;
	struct sigpending *pending;
	unsigned long flags;
	int ret;

	BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));

	ret = -1;
	if (!likely(lock_task_sighand(t, &flags)))
		goto ret;

	ret = 1; /* the signal is ignored */
	if (!prepare_signal(sig, t, 0))
		goto out;

	ret = 0;
	if (unlikely(!list_empty(&q->list))) {
		/*
		 * If an SI_TIMER entry is already queue just increment
		 * the overrun count.
		 */
		BUG_ON(q->info.si_code != SI_TIMER);
		q->info.si_overrun++;
		goto out;
	}
	q->info.si_overrun = 0;

	signalfd_notify(t, sig);
	pending = group ? &t->signal->shared_pending : &t->pending;
	list_add_tail(&q->list, &pending->list);
	sigaddset(&pending->signal, sig);
	complete_signal(sig, t, group);
out:
	unlock_task_sighand(t, &flags);
ret:
	return ret;
}

Project: linux-2.6

int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
{
	int signr;

	/* We only dequeue private signals from ourselves, we don't let
	 * signalfd steal them
	 */
	signr = __dequeue_signal(&tsk->pending, mask, info);
	if (!signr) {
		signr = __dequeue_signal(&tsk->signal->shared_pending,
					 mask, info);
		/*
		 * itimer signal ?
		 *
		 * itimers are process shared and we restart periodic
		 * itimers in the signal delivery path to prevent DoS
		 * attacks in the high resolution timer case. This is
		 * compliant with the old way of self restarting
		 * itimers, as the SIGALRM is a legacy signal and only
		 * queued once. Changing the restart behaviour to
		 * restart the timer in the signal dequeue path is
		 * reducing the timer noise on heavy loaded !highres
		 * systems too.
		 */
		if (unlikely(signr == SIGALRM)) {
			struct hrtimer *tmr = &tsk->signal->real_timer;

			if (!hrtimer_is_queued(tmr) &&
			    tsk->signal->it_real_incr.tv64 != 0) {
				hrtimer_forward(tmr, tmr->base->get_time(),
						tsk->signal->it_real_incr);
				hrtimer_restart(tmr);
			}
		}
	}

	recalc_sigpending();
	if (!signr)
		return 0;

	if (unlikely(sig_kernel_stop(signr))) {
		/*
		 * Set a marker that we have dequeued a stop signal.  Our
		 * caller might release the siglock and then the pending
		 * stop signal it is about to process is no longer in the
		 * pending bitmasks, but must still be cleared by a SIGCONT
		 * (and overruled by a SIGKILL).  So those cases clear this
		 * shared flag after we've set it.  Note that this flag may
		 * remain set after the signal we return is ignored or
		 * handled.  That doesn't matter because its only purpose
		 * is to alert stop-signal processing code when another
		 * processor has come along and cleared the flag.
		 */
		tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
	}
	if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
		/*
		 * Release the siglock to ensure proper locking order
		 * of timer locks outside of siglocks.  Note, we leave
		 * irqs disabled here, since the posix-timers code is
		 * about to disable them again anyway.
		 */
		spin_unlock(&tsk->sighand->siglock);
		do_schedule_next_timer(info);
		spin_lock(&tsk->sighand->siglock);
	}
	return signr;
}

Project: linux-2.6

int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
{
	int error;

	spin_lock_irq(&current->sighand->siglock);
	if (oldset)
		*oldset = current->blocked;

	error = 0;
	switch (how) {
	case SIG_BLOCK:
		sigorsets(&current->blocked, &current->blocked, set);
		break;
	case SIG_UNBLOCK:
		signandsets(&current->blocked, &current->blocked, set);
		break;
	case SIG_SETMASK:
		current->blocked = *set;
		break;
	default:
		error = -EINVAL;
	}
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	return error;
}

Project: linux-2.6

SYSCALL_DEFINE0(pause)
{
	current->state = TASK_INTERRUPTIBLE;
	schedule();
	return -ERESTARTNOHAND;
}

Project: linux-2.6

static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
{
	if (arch_ptrace_stop_needed(exit_code, info)) {
		/*
		 * The arch code has something special to do before a
		 * ptrace stop.  This is allowed to block, e.g. for faults
		 * on user stack pages.  We can't keep the siglock while
		 * calling arch_ptrace_stop, so we must release it now.
		 * To preserve proper semantics, we must do this before
		 * any signal bookkeeping like checking group_stop_count.
		 * Meanwhile, a SIGKILL could come in before we retake the
		 * siglock.  That must prevent us from sleeping in TASK_TRACED.
		 * So after regaining the lock, we must check for SIGKILL.
		 */
		spin_unlock_irq(&current->sighand->siglock);
		arch_ptrace_stop(exit_code, info);
		spin_lock_irq(&current->sighand->siglock);
		if (sigkill_pending(current))
			return;
	}

	/*
	 * If there is a group stop in progress,
	 * we must participate in the bookkeeping.
	 */
	if (current->signal->group_stop_count > 0)
		--current->signal->group_stop_count;

	current->last_siginfo = info;
	current->exit_code = exit_code;

	/* Let the debugger run.  */
	__set_current_state(TASK_TRACED);
	spin_unlock_irq(&current->sighand->siglock);
	read_lock(&tasklist_lock);
	if (may_ptrace_stop()) {
		do_notify_parent_cldstop(current, CLD_TRAPPED);
		/*
		 * Don't want to allow preemption here, because
		 * sys_ptrace() needs this task to be inactive.
		 *
		 * XXX: implement read_unlock_no_resched().
		 */
		preempt_disable();
		read_unlock(&tasklist_lock);
		preempt_enable_no_resched();
		schedule();
	} else {
		/*
		 * By the time we got the lock, our tracer went away.
		 * Don't drop the lock yet, another tracer may come.
		 */
		__set_current_state(TASK_RUNNING);
		if (clear_code)
			current->exit_code = 0;
		read_unlock(&tasklist_lock);
	}

	/*
	 * While in TASK_TRACED, we were considered "frozen enough".
	 * Now that we woke up, it's crucial if we're supposed to be
	 * frozen that we freeze now before running anything substantial.
	 */
	try_to_freeze();

	/*
	 * We are back.  Now reacquire the siglock before touching
	 * last_siginfo, so that we are sure to have synchronized with
	 * any signal-sending on another CPU that wants to examine it.
	 */
	spin_lock_irq(&current->sighand->siglock);
	current->last_siginfo = NULL;

	/*
	 * Queued signals ignored us while we were stopped for tracing.
	 * So check for any that we should take before resuming user mode.
	 * This sets TIF_SIGPENDING, but never clears it.
	 */
	recalc_sigpending_tsk(current);
}

Project: linux-2.6

static int check_kill_permission(int sig, struct siginfo *info,
				 struct task_struct *t)
{
	const struct cred *cred = current_cred(), *tcred;
	struct pid *sid;
	int error;

	if (!valid_signal(sig))
		return -EINVAL;

	if (info != SEND_SIG_NOINFO && (is_si_special(info) || SI_FROMKERNEL(info)))
		return 0;

	error = audit_signal_info(sig, t); /* Let audit system see the signal */
	if (error)
		return error;

	tcred = __task_cred(t);
	if ((cred->euid ^ tcred->suid) &&
	    (cred->euid ^ tcred->uid) &&
	    (cred->uid  ^ tcred->suid) &&
	    (cred->uid  ^ tcred->uid) &&
	    !capable(CAP_KILL)) {
		switch (sig) {
		case SIGCONT:
			sid = task_session(t);
			/*
			 * We don't return the error if sid == NULL. The
			 * task was unhashed, the caller must notice this.
			 */
			if (!sid || sid == task_session(current))
				break;
		default:
			return -EPERM;
		}
	}

	return security_task_kill(t, info, sig, 0);
}

Project: linux-2.6

force_sig_specific(int sig, struct task_struct *t)
{
	force_sig_info(sig, SEND_SIG_FORCED, t);
}

Project: linux-2.6

int unhandled_signal(struct task_struct *tsk, int sig)
{
	void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
	if (is_global_init(tsk))
		return 1;
	if (handler != SIG_IGN && handler != SIG_DFL)
		return 0;
	return !tracehook_consider_fatal_signal(tsk, sig);
}

Project: linux-2.6

static void complete_signal(int sig, struct task_struct *p, int group)
{
	struct signal_struct *signal = p->signal;
	struct task_struct *t;

	/*
	 * Now find a thread we can wake up to take the signal off the queue.
	 *
	 * If the main thread wants the signal, it gets first crack.
	 * Probably the least surprising to the average bear.
	 */
	if (wants_signal(sig, p))
		t = p;
	else if (!group || thread_group_empty(p))
		/*
		 * There is just one thread and it does not need to be woken.
		 * It will dequeue unblocked signals before it runs again.
		 */
		return;
	else {
		/*
		 * Otherwise try to find a suitable thread.
		 */
		t = signal->curr_target;
		while (!wants_signal(sig, t)) {
			t = next_thread(t);
			if (t == signal->curr_target)
				/*
				 * No thread needs to be woken.
				 * Any eligible threads will see
				 * the signal in the queue soon.
				 */
				return;
		}
		signal->curr_target = t;
	}

	/*
	 * Found a killable thread.  If the signal will be fatal,
	 * then start taking the whole group down immediately.
	 */
	if (sig_fatal(p, sig) &&
	    !(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
	    !sigismember(&t->real_blocked, sig) &&
	    (sig == SIGKILL ||
	     !tracehook_consider_fatal_signal(t, sig))) {
		/*
		 * This signal will be fatal to the whole group.
		 */
		if (!sig_kernel_coredump(sig)) {
			/*
			 * Start a group exit and wake everybody up.
			 * This way we don't have other threads
			 * running and doing things after a slower
			 * thread has the fatal signal pending.
			 */
			signal->flags = SIGNAL_GROUP_EXIT;
			signal->group_exit_code = sig;
			signal->group_stop_count = 0;
			t = p;
			do {
				sigaddset(&t->pending.signal, SIGKILL);
				signal_wake_up(t, 1);
			} while_each_thread(p, t);
			return;
		}
	}

	/*
	 * The signal is already in the shared-pending queue.
	 * Tell the chosen thread to wake up and dequeue it.
	 */
	signal_wake_up(t, sig == SIGKILL);
	return;
}

Project: linux-2.6

static int do_signal_stop(int signr)
{
	struct signal_struct *sig = current->signal;
	int stop_count;

	if (sig->group_stop_count > 0) {
		/*
		 * There is a group stop in progress.  We don't need to
		 * start another one.
		 */
		stop_count = --sig->group_stop_count;
	} else {
		struct task_struct *t;

		if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
		    unlikely(signal_group_exit(sig)))
			return 0;
		/*
		 * There is no group stop already in progress.
		 * We must initiate one now.
		 */
		sig->group_exit_code = signr;

		stop_count = 0;
		for (t = next_thread(current); t != current; t = next_thread(t))
			/*
			 * Setting state to TASK_STOPPED for a group
			 * stop is always done with the siglock held,
			 * so this check has no races.
			 */
			if (!(t->flags & PF_EXITING) &&
			    !task_is_stopped_or_traced(t)) {
				stop_count++;
				signal_wake_up(t, 0);
			}
		sig->group_stop_count = stop_count;
	}

	if (stop_count == 0)
		sig->flags = SIGNAL_STOP_STOPPED;
	current->exit_code = sig->group_exit_code;
	__set_current_state(TASK_STOPPED);

	spin_unlock_irq(&current->sighand->siglock);
	finish_stop(stop_count);
	return 1;
}

Project: linux-2.6

static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
{
	struct sigqueue *q, *n;
	sigset_t m;

	sigandsets(&m, mask, &s->signal);
	if (sigisemptyset(&m))
		return 0;

	signandsets(&s->signal, &s->signal, mask);
	list_for_each_entry_safe(q, n, &s->list, list) {
		if (sigismember(mask, q->info.si_signo)) {
			list_del_init(&q->list);
			__sigqueue_free(q);
		}
	}
	return 1;
}

Project: linux-2.6

SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
	return do_sigpending(set, sigsetsize);
}

Project: linux-2.6

static int recalc_sigpending_tsk(struct task_struct *t)
{
	if (t->signal->group_stop_count > 0 ||
	    PENDING(&t->pending, &t->blocked) ||
	    PENDING(&t->signal->shared_pending, &t->blocked)) {
		set_tsk_thread_flag(t, TIF_SIGPENDING);
		return 1;
	}
	/*
	 * We must never clear the flag in another thread, or in current
	 * when it's possible the current syscall is returning -ERESTART*.
	 * So we don't clear it here, and only callers who know they should do.
	 */
	return 0;
}

Project: linux-2.6

int do_notify_parent(struct task_struct *tsk, int sig)
{
	struct siginfo info;
	unsigned long flags;
	struct sighand_struct *psig;
	int ret = sig;

	BUG_ON(sig == -1);

 	/* do_notify_parent_cldstop should have been called instead.  */
 	BUG_ON(task_is_stopped_or_traced(tsk));

	BUG_ON(!task_ptrace(tsk) &&
	       (tsk->group_leader != tsk || !thread_group_empty(tsk)));

	info.si_signo = sig;
	info.si_errno = 0;
	/*
	 * we are under tasklist_lock here so our parent is tied to
	 * us and cannot exit and release its namespace.
	 *
	 * the only it can is to switch its nsproxy with sys_unshare,
	 * bu uncharing pid namespaces is not allowed, so we'll always
	 * see relevant namespace
	 *
	 * write_lock() currently calls preempt_disable() which is the
	 * same as rcu_read_lock(), but according to Oleg, this is not
	 * correct to rely on this
	 */
	rcu_read_lock();
	info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
	info.si_uid = __task_cred(tsk)->uid;
	rcu_read_unlock();

	info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
				tsk->signal->utime));
	info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
				tsk->signal->stime));

	info.si_status = tsk->exit_code & 0x7f;
	if (tsk->exit_code & 0x80)
		info.si_code = CLD_DUMPED;
	else if (tsk->exit_code & 0x7f)
		info.si_code = CLD_KILLED;
	else {
		info.si_code = CLD_EXITED;
		info.si_status = tsk->exit_code >> 8;
	}

	psig = tsk->parent->sighand;
	spin_lock_irqsave(&psig->siglock, flags);
	if (!task_ptrace(tsk) && sig == SIGCHLD &&
	    (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
	     (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
		/*
		 * We are exiting and our parent doesn't care.  POSIX.1
		 * defines special semantics for setting SIGCHLD to SIG_IGN
		 * or setting the SA_NOCLDWAIT flag: we should be reaped
		 * automatically and not left for our parent's wait4 call.
		 * Rather than having the parent do it as a magic kind of
		 * signal handler, we just set this to tell do_exit that we
		 * can be cleaned up without becoming a zombie.  Note that
		 * we still call __wake_up_parent in this case, because a
		 * blocked sys_wait4 might now return -ECHILD.
		 *
		 * Whether we send SIGCHLD or not for SA_NOCLDWAIT
		 * is implementation-defined: we do (if you don't want
		 * it, just use SIG_IGN instead).
		 */
		ret = tsk->exit_signal = -1;
		if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
			sig = -1;
	}
	if (valid_signal(sig) && sig > 0)
		__group_send_sig_info(sig, &info, tsk->parent);
	__wake_up_parent(tsk, tsk->parent);
	spin_unlock_irqrestore(&psig->siglock, flags);

	return ret;
}

Project: linux-2.6

kill_proc_info(int sig, struct siginfo *info, pid_t pid)
{
	int error;
	rcu_read_lock();
	error = kill_pid_info(sig, info, find_vpid(pid));
	rcu_read_unlock();
	return error;
}

Project: linux-2.6

long do_sigpending(void __user *set, unsigned long sigsetsize)
{
	long error = -EINVAL;
	sigset_t pending;

	if (sigsetsize > sizeof(sigset_t))
		goto out;

	spin_lock_irq(&current->sighand->siglock);
	sigorsets(&pending, &current->pending.signal,
		  &current->signal->shared_pending.signal);
	spin_unlock_irq(&current->sighand->siglock);

	/* Outside the lock because only this thread touches it.  */
	sigandsets(&pending, &current->blocked, &pending);

	error = -EFAULT;
	if (!copy_to_user(set, &pending, sigsetsize))
		error = 0;

out:
	return error;
}

Project: linux-2.6

static int ptrace_signal(int signr, siginfo_t *info,
			 struct pt_regs *regs, void *cookie)
{
	if (!task_ptrace(current))
		return signr;

	ptrace_signal_deliver(regs, cookie);

	/* Let the debugger run.  */
	ptrace_stop(signr, 0, info);

	/* We're back.  Did the debugger cancel the sig?  */
	signr = current->exit_code;
	if (signr == 0)
		return signr;

	current->exit_code = 0;

	/* Update the siginfo structure if the signal has
	   changed.  If the debugger wanted something
	   specific in the siginfo structure then it should
	   have updated *info via PTRACE_SETSIGINFO.  */
	if (signr != info->si_signo) {
		info->si_signo = signr;
		info->si_errno = 0;
		info->si_code = SI_USER;
		info->si_pid = task_pid_vnr(current->parent);
		info->si_uid = task_uid(current->parent);
	}

	/* If the (new) signal is now blocked, requeue it.  */
	if (sigismember(&current->blocked, signr)) {
		specific_send_sig_info(signr, info, current);
		signr = 0;
	}

	return signr;
}

Project: linux-2.6

void recalc_sigpending(void)
{
	if (unlikely(tracehook_force_sigpending()))
		set_thread_flag(TIF_SIGPENDING);
	else if (!recalc_sigpending_tsk(current) && !freezing(current))
		clear_thread_flag(TIF_SIGPENDING);

}

Project: linux-2.6

int next_signal(struct sigpending *pending, sigset_t *mask)
{
	unsigned long i, *s, *m, x;
	int sig = 0;
	
	s = pending->signal.sig;
	m = mask->sig;
	switch (_NSIG_WORDS) {
	default:
		for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m)
			if ((x = *s &~ *m) != 0) {
				sig = ffz(~x) + i*_NSIG_BPW + 1;
				break;
			}
		break;

	case 2: if ((x = s[0] &~ m[0]) != 0)
			sig = 1;
		else if ((x = s[1] &~ m[1]) != 0)
			sig = _NSIG_BPW + 1;
		else
			break;
		sig += ffz(~x);
		break;

	case 1: if ((x = *s &~ *m) != 0)
			sig = ffz(~x) + 1;
		break;
	}
	
	return sig;
}

Project: linux-2.6

int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
			  struct pt_regs *regs, void *cookie)
{
	struct sighand_struct *sighand = current->sighand;
	struct signal_struct *signal = current->signal;
	int signr;

relock:
	/*
	 * We'll jump back here after any time we were stopped in TASK_STOPPED.
	 * While in TASK_STOPPED, we were considered "frozen enough".
	 * Now that we woke up, it's crucial if we're supposed to be
	 * frozen that we freeze now before running anything substantial.
	 */
	try_to_freeze();

	spin_lock_irq(&sighand->siglock);
	/*
	 * Every stopped thread goes here after wakeup. Check to see if
	 * we should notify the parent, prepare_signal(SIGCONT) encodes
	 * the CLD_ si_code into SIGNAL_CLD_MASK bits.
	 */
	if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
		int why = (signal->flags & SIGNAL_STOP_CONTINUED)
				? CLD_CONTINUED : CLD_STOPPED;
		signal->flags &= ~SIGNAL_CLD_MASK;
		spin_unlock_irq(&sighand->siglock);

		if (unlikely(!tracehook_notify_jctl(1, why)))
			goto relock;

		read_lock(&tasklist_lock);
		do_notify_parent_cldstop(current->group_leader, why);
		read_unlock(&tasklist_lock);
		goto relock;
	}

	for (;;) {
		struct k_sigaction *ka;

		if (unlikely(signal->group_stop_count > 0) &&
		    do_signal_stop(0))
			goto relock;

		/*
		 * Tracing can induce an artifical signal and choose sigaction.
		 * The return value in @signr determines the default action,
		 * but @info->si_signo is the signal number we will report.
		 */
		signr = tracehook_get_signal(current, regs, info, return_ka);
		if (unlikely(signr < 0))
			goto relock;
		if (unlikely(signr != 0))
			ka = return_ka;
		else {
			signr = dequeue_signal(current, &current->blocked,
					       info);

			if (!signr)
				break; /* will return 0 */

			if (signr != SIGKILL) {
				signr = ptrace_signal(signr, info,
						      regs, cookie);
				if (!signr)
					continue;
			}

			ka = &sighand->action[signr-1];
		}

		if (ka->sa.sa_handler == SIG_IGN) /* Do nothing.  */
			continue;
		if (ka->sa.sa_handler != SIG_DFL) {
			/* Run the handler.  */
			*return_ka = *ka;

			if (ka->sa.sa_flags & SA_ONESHOT)
				ka->sa.sa_handler = SIG_DFL;

			break; /* will return non-zero "signr" value */
		}

		/*
		 * Now we are doing the default action for this signal.
		 */
		if (sig_kernel_ignore(signr)) /* Default is nothing. */
			continue;

		/*
		 * Global init gets no signals it doesn't want.
		 * Container-init gets no signals it doesn't want from same
		 * container.
		 *
		 * Note that if global/container-init sees a sig_kernel_only()
		 * signal here, the signal must have been generated internally
		 * or must have come from an ancestor namespace. In either
		 * case, the signal cannot be dropped.
		 */
		if (unlikely(signal->flags & SIGNAL_UNKILLABLE) &&
				!sig_kernel_only(signr))
			continue;

		if (sig_kernel_stop(signr)) {
			/*
			 * The default action is to stop all threads in
			 * the thread group.  The job control signals
			 * do nothing in an orphaned pgrp, but SIGSTOP
			 * always works.  Note that siglock needs to be
			 * dropped during the call to is_orphaned_pgrp()
			 * because of lock ordering with tasklist_lock.
			 * This allows an intervening SIGCONT to be posted.
			 * We need to check for that and bail out if necessary.
			 */
			if (signr != SIGSTOP) {
				spin_unlock_irq(&sighand->siglock);

				/* signals can be posted during this window */

				if (is_current_pgrp_orphaned())
					goto relock;

				spin_lock_irq(&sighand->siglock);
			}

			if (likely(do_signal_stop(info->si_signo))) {
				/* It released the siglock.  */
				goto relock;
			}

			/*
			 * We didn't actually stop, due to a race
			 * with SIGCONT or something like that.
			 */
			continue;
		}

		spin_unlock_irq(&sighand->siglock);

		/*
		 * Anything else is fatal, maybe with a core dump.
		 */
		current->flags |= PF_SIGNALED;

		if (sig_kernel_coredump(signr)) {
			if (print_fatal_signals)
				print_fatal_signal(regs, info->si_signo);
			/*
			 * If it was able to dump core, this kills all
			 * other threads in the group and synchronizes with
			 * their demise.  If we lost the race with another
			 * thread getting here, it set group_exit_code
			 * first and our do_group_exit call below will use
			 * that value and ignore the one we pass it.
			 */
			do_coredump(info->si_signo, info->si_signo, regs);
		}

		/*
		 * Death signals, no core dump.
		 */
		do_group_exit(info->si_signo);
		/* NOTREACHED */
	}
	spin_unlock_irq(&sighand->siglock);
	return signr;
}

Project: linux-2.6

static inline int may_ptrace_stop(void)
{
	if (!likely(task_ptrace(current)))
		return 0;
	/*
	 * Are we in the middle of do_coredump?
	 * If so and our tracer is also part of the coredump stopping
	 * is a deadlock situation, and pointless because our tracer
	 * is dead so don't allow us to stop.
	 * If SIGKILL was already sent before the caller unlocked
	 * ->siglock we must see ->core_state != NULL. Otherwise it
	 * is safe to enter schedule().
	 */
	if (unlikely(current->mm->core_state) &&
	    unlikely(current->mm == current->parent->mm))
		return 0;

	return 1;
}

Project: linux-2.6

SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
		old_sigset_t __user *, oset)
{
	int error;
	old_sigset_t old_set, new_set;

	if (set) {
		error = -EFAULT;
		if (copy_from_user(&new_set, set, sizeof(*set)))
			goto out;
		new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));

		spin_lock_irq(&current->sighand->siglock);
		old_set = current->blocked.sig[0];

		error = 0;
		switch (how) {
		default:
			error = -EINVAL;
			break;
		case SIG_BLOCK:
			sigaddsetmask(&current->blocked, new_set);
			break;
		case SIG_UNBLOCK:
			sigdelsetmask(&current->blocked, new_set);
			break;
		case SIG_SETMASK:
			current->blocked.sig[0] = new_set;
			break;
		}

		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
		if (error)
			goto out;
		if (oset)
			goto set_old;
	} else if (oset) {
		old_set = current->blocked.sig[0];
	set_old:
		error = -EFAULT;
		if (copy_to_user(oset, &old_set, sizeof(*oset)))
			goto out;
	}
	error = 0;
out:
	return error;
}

Project: linux-2.6

static inline void __wake_up_parent(struct task_struct *p,
				    struct task_struct *parent)
{
	wake_up_interruptible_sync(&parent->signal->wait_chldexit);
}

Project: linux-2.6

static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
{
	struct siginfo info;
	unsigned long flags;
	struct task_struct *parent;
	struct sighand_struct *sighand;

	if (task_ptrace(tsk))
		parent = tsk->parent;
	else {
		tsk = tsk->group_leader;
		parent = tsk->real_parent;
	}

	info.si_signo = SIGCHLD;
	info.si_errno = 0;
	/*
	 * see comment in do_notify_parent() abot the following 3 lines
	 */
	rcu_read_lock();
	info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
	info.si_uid = __task_cred(tsk)->uid;
	rcu_read_unlock();

	info.si_utime = cputime_to_clock_t(tsk->utime);
	info.si_stime = cputime_to_clock_t(tsk->stime);

 	info.si_code = why;
 	switch (why) {
 	case CLD_CONTINUED:
 		info.si_status = SIGCONT;
 		break;
 	case CLD_STOPPED:
 		info.si_status = tsk->signal->group_exit_code & 0x7f;
 		break;
 	case CLD_TRAPPED:
 		info.si_status = tsk->exit_code & 0x7f;
 		break;
 	default:
 		BUG();
 	}

	sighand = parent->sighand;
	spin_lock_irqsave(&sighand->siglock, flags);
	if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN &&
	    !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
		__group_send_sig_info(SIGCHLD, &info, parent);
	/*
	 * Even if SIGCHLD is not generated, we must wake up wait4 calls.
	 */
	__wake_up_parent(tsk, parent);
	spin_unlock_irqrestore(&sighand->siglock, flags);
}

Project: linux-2.6

send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
	int ret;
	unsigned long flags;

	/*
	 * Make sure legacy kernel users don't send in bad values
	 * (normal paths check this in check_kill_permission).
	 */
	if (!valid_signal(sig))
		return -EINVAL;

	spin_lock_irqsave(&p->sighand->siglock, flags);
	ret = specific_send_sig_info(sig, info, p);
	spin_unlock_irqrestore(&p->sighand->siglock, flags);
	return ret;
}

Project: linux-2.6

int __fatal_signal_pending(struct task_struct *tsk)
{
	return sigismember(&tsk->pending.signal, SIGKILL);
}

Project: linux-2.6

int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
{
	int err;

	if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
		return -EFAULT;
	if (from->si_code < 0)
		return __copy_to_user(to, from, sizeof(siginfo_t))
			? -EFAULT : 0;
	/*
	 * If you change siginfo_t structure, please be sure
	 * this code is fixed accordingly.
	 * Please remember to update the signalfd_copyinfo() function
	 * inside fs/signalfd.c too, in case siginfo_t changes.
	 * It should never copy any pad contained in the structure
	 * to avoid security leaks, but must copy the generic
	 * 3 ints plus the relevant union member.
	 */
	err = __put_user(from->si_signo, &to->si_signo);
	err |= __put_user(from->si_errno, &to->si_errno);
	err |= __put_user((short)from->si_code, &to->si_code);
	switch (from->si_code & __SI_MASK) {
	case __SI_KILL:
		err |= __put_user(from->si_pid, &to->si_pid);
		err |= __put_user(from->si_uid, &to->si_uid);
		break;
	case __SI_TIMER:
		 err |= __put_user(from->si_tid, &to->si_tid);
		 err |= __put_user(from->si_overrun, &to->si_overrun);
		 err |= __put_user(from->si_ptr, &to->si_ptr);
		break;
	case __SI_POLL:
		err |= __put_user(from->si_band, &to->si_band);
		err |= __put_user(from->si_fd, &to->si_fd);
		break;
	case __SI_FAULT:
		err |= __put_user(from->si_addr, &to->si_addr);
#ifdef __ARCH_SI_TRAPNO
		err |= __put_user(from->si_trapno, &to->si_trapno);
#endif
		break;
	case __SI_CHLD:
		err |= __put_user(from->si_pid, &to->si_pid);
		err |= __put_user(from->si_uid, &to->si_uid);
		err |= __put_user(from->si_status, &to->si_status);
		err |= __put_user(from->si_utime, &to->si_utime);
		err |= __put_user(from->si_stime, &to->si_stime);
		break;
	case __SI_RT: /* This is not generated by the kernel as of now. */
	case __SI_MESGQ: /* But this is */
		err |= __put_user(from->si_pid, &to->si_pid);
		err |= __put_user(from->si_uid, &to->si_uid);
		err |= __put_user(from->si_ptr, &to->si_ptr);
		break;
	default: /* this is just in case for now ... */
		err |= __put_user(from->si_pid, &to->si_pid);
		err |= __put_user(from->si_uid, &to->si_uid);
		break;
	}
	return err;
}

Project: linux-2.6

SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
	return do_sigpending(set, sizeof(*set));
}

Project: linux-2.6

static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
					 int override_rlimit)
{
	struct sigqueue *q = NULL;
	struct user_struct *user;

	/*
	 * We won't get problems with the target's UID changing under us
	 * because changing it requires RCU be used, and if t != current, the
	 * caller must be holding the RCU readlock (by way of a spinlock) and
	 * we use RCU protection here
	 */
	user = get_uid(__task_cred(t)->user);
	atomic_inc(&user->sigpending);
	if (override_rlimit ||
	    atomic_read(&user->sigpending) <=
			t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
		q = kmem_cache_alloc(sigqueue_cachep, flags);
	if (unlikely(q == NULL)) {
		atomic_dec(&user->sigpending);
		free_uid(user);
	} else {
		INIT_LIST_HEAD(&q->list);
		q->flags = 0;
		q->user = user;
	}

	return q;
}

Project: linux-2.6

static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
{
	struct sigqueue *q, *first = NULL;

	/*
	 * Collect the siginfo appropriate to this signal.  Check if
	 * there is another siginfo for the same signal.
	*/
	list_for_each_entry(q, &list->list, list) {
		if (q->info.si_signo == sig) {
			if (first)
				goto still_pending;
			first = q;
		}
	}

	sigdelset(&list->signal, sig);

	if (first) {
still_pending:
		list_del_init(&first->list);
		copy_siginfo(info, &first->info);
		__sigqueue_free(first);
	} else {
		/* Ok, it wasn't in the queue.  This must be
		   a fast-pathed signal or we must have been
		   out of queue space.  So zero out the info.
		 */
		info->si_signo = sig;
		info->si_errno = 0;
		info->si_code = 0;
		info->si_pid = 0;
		info->si_uid = 0;
	}
}

Project: linux-2.6

static void print_fatal_signal(struct pt_regs *regs, int signr)
{
	printk("%s/%d: potentially unexpected fatal signal %d.\n",
		current->comm, task_pid_nr(current), signr);

#if defined(__i386__) && !defined(__arch_um__)
	printk("code at %08lx: ", regs->ip);
	{
		int i;
		for (i = 0; i < 16; i++) {
			unsigned char insn;

			__get_user(insn, (unsigned char *)(regs->ip + i));
			printk("%02x ", insn);
		}
	}
#endif
	printk("\n");
	preempt_disable();
	show_regs(regs);
	preempt_enable();
}

Project: linux-2.6

SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
	struct siginfo info;

	info.si_signo = sig;
	info.si_errno = 0;
	info.si_code = SI_USER;
	info.si_pid = task_tgid_vnr(current);
	info.si_uid = current_uid();

	return kill_something_info(sig, &info, pid);
}

Project: linux-2.6

int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
		      uid_t uid, uid_t euid, u32 secid)
{
	int ret = -EINVAL;
	struct task_struct *p;
	const struct cred *pcred;

	if (!valid_signal(sig))
		return ret;

	read_lock(&tasklist_lock);
	p = pid_task(pid, PIDTYPE_PID);
	if (!p) {
		ret = -ESRCH;
		goto out_unlock;
	}
	pcred = __task_cred(p);
	if ((info == SEND_SIG_NOINFO ||
	     (!is_si_special(info) && SI_FROMUSER(info))) &&
	    euid != pcred->suid && euid != pcred->uid &&
	    uid  != pcred->suid && uid  != pcred->uid) {
		ret = -EPERM;
		goto out_unlock;
	}
	ret = security_task_kill(p, info, sig, secid);
	if (ret)
		goto out_unlock;
	if (sig && p->sighand) {
		unsigned long flags;
		spin_lock_irqsave(&p->sighand->siglock, flags);
		ret = __send_signal(sig, info, p, 1, 0);
		spin_unlock_irqrestore(&p->sighand->siglock, flags);
	}
out_unlock:
	read_unlock(&tasklist_lock);
	return ret;
}

Project: linux-2.6

static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
			int group)
{
	int from_ancestor_ns = 0;

#ifdef CONFIG_PID_NS
	if (!is_si_special(info) && SI_FROMUSER(info) &&
			task_pid_nr_ns(current, task_active_pid_ns(t)) <= 0)
		from_ancestor_ns = 1;
#endif

	return __send_signal(sig, info, t, group, from_ancestor_ns);
}

Project: linux-2.6

SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
	sigset_t newset;

	/* XXX: Don't preclude handling different sized sigset_t's.  */
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	if (copy_from_user(&newset, unewset, sizeof(newset)))
		return -EFAULT;
	sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));

	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	current->blocked = newset;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_restore_sigmask();
	return -ERESTARTNOHAND;
}