*/
#include <linux/slab.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/siginfo.h>
+#include <asm/cacheflush.h>
#include "audit.h" /* audit_signal_info() */
/*
(handler == SIG_DFL && sig_kernel_ignore(sig));
}
-static int sig_task_ignored(struct task_struct *t, int sig,
- int from_ancestor_ns)
+static int sig_task_ignored(struct task_struct *t, int sig, bool force)
{
void __user *handler;
handler = sig_handler(t, sig);
if (unlikely(t->signal->flags & SIGNAL_UNKILLABLE) &&
- handler == SIG_DFL && !from_ancestor_ns)
+ handler == SIG_DFL && !force)
return 1;
return sig_handler_ignored(handler, sig);
}
-static int sig_ignored(struct task_struct *t, int sig, int from_ancestor_ns)
+static int sig_ignored(struct task_struct *t, int sig, bool force)
{
/*
* Blocked signals are never ignored, since the
if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
return 0;
- if (!sig_task_ignored(t, sig, from_ancestor_ns))
+ if (!sig_task_ignored(t, sig, force))
return 0;
/*
* Tracers may want to know about even ignored signals.
*/
- return !tracehook_consider_ignored_signal(t, sig);
+ return !t->ptrace;
}
/*
static int recalc_sigpending_tsk(struct task_struct *t)
{
- if (t->signal->group_stop_count > 0 ||
+ if ((t->jobctl & JOBCTL_PENDING_MASK) ||
PENDING(&t->pending, &t->blocked) ||
PENDING(&t->signal->shared_pending, &t->blocked)) {
set_tsk_thread_flag(t, TIF_SIGPENDING);
void recalc_sigpending(void)
{
- if (unlikely(tracehook_force_sigpending()))
- set_thread_flag(TIF_SIGPENDING);
- else if (!recalc_sigpending_tsk(current) && !freezing(current))
+ if (!recalc_sigpending_tsk(current) && !freezing(current))
clear_thread_flag(TIF_SIGPENDING);
}
/* Given the mask, find the first available signal that should be serviced. */
+#define SYNCHRONOUS_MASK \
+ (sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
+ sigmask(SIGTRAP) | sigmask(SIGFPE))
+
int next_signal(struct sigpending *pending, sigset_t *mask)
{
unsigned long i, *s, *m, x;
s = pending->signal.sig;
m = mask->sig;
+
+ /*
+ * Handle the first word specially: it contains the
+ * synchronous signals that need to be dequeued first.
+ */
+ x = *s &~ *m;
+ if (x) {
+ if (x & SYNCHRONOUS_MASK)
+ x &= SYNCHRONOUS_MASK;
+ sig = ffz(~x) + 1;
+ return 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;
- }
+ for (i = 1; i < _NSIG_WORDS; ++i) {
+ x = *++s &~ *++m;
+ if (!x)
+ continue;
+ 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
+ case 2:
+ x = s[1] &~ m[1];
+ if (!x)
break;
- sig += ffz(~x);
+ sig = ffz(~x) + _NSIG_BPW + 1;
break;
- case 1: if ((x = *s &~ *m) != 0)
- sig = ffz(~x) + 1;
+ case 1:
+ /* Nothing to do */
break;
}
current->comm, current->pid, sig);
}
+/**
+ * task_set_jobctl_pending - set jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to set
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK | %JOBCTL_STOP_CONSUME | %JOBCTL_STOP_SIGMASK |
+ * %JOBCTL_TRAPPING. If stop signo is being set, the existing signo is
+ * cleared. If @task is already being killed or exiting, this function
+ * becomes noop.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if @mask is set, %false if made noop because @task was dying.
+ */
+bool task_set_jobctl_pending(struct task_struct *task, unsigned int mask)
+{
+ BUG_ON(mask & ~(JOBCTL_PENDING_MASK | JOBCTL_STOP_CONSUME |
+ JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING));
+ BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK));
+
+ if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING)))
+ return false;
+
+ if (mask & JOBCTL_STOP_SIGMASK)
+ task->jobctl &= ~JOBCTL_STOP_SIGMASK;
+
+ task->jobctl |= mask;
+ return true;
+}
+
+/**
+ * task_clear_jobctl_trapping - clear jobctl trapping bit
+ * @task: target task
+ *
+ * If JOBCTL_TRAPPING is set, a ptracer is waiting for us to enter TRACED.
+ * Clear it and wake up the ptracer. Note that we don't need any further
+ * locking. @task->siglock guarantees that @task->parent points to the
+ * ptracer.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_trapping(struct task_struct *task)
+{
+ if (unlikely(task->jobctl & JOBCTL_TRAPPING)) {
+ task->jobctl &= ~JOBCTL_TRAPPING;
+ wake_up_bit(&task->jobctl, JOBCTL_TRAPPING_BIT);
+ }
+}
+
+/**
+ * task_clear_jobctl_pending - clear jobctl pending bits
+ * @task: target task
+ * @mask: pending bits to clear
+ *
+ * Clear @mask from @task->jobctl. @mask must be subset of
+ * %JOBCTL_PENDING_MASK. If %JOBCTL_STOP_PENDING is being cleared, other
+ * STOP bits are cleared together.
+ *
+ * If clearing of @mask leaves no stop or trap pending, this function calls
+ * task_clear_jobctl_trapping().
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+void task_clear_jobctl_pending(struct task_struct *task, unsigned int mask)
+{
+ BUG_ON(mask & ~JOBCTL_PENDING_MASK);
+
+ if (mask & JOBCTL_STOP_PENDING)
+ mask |= JOBCTL_STOP_CONSUME | JOBCTL_STOP_DEQUEUED;
+
+ task->jobctl &= ~mask;
+
+ if (!(task->jobctl & JOBCTL_PENDING_MASK))
+ task_clear_jobctl_trapping(task);
+}
+
+/**
+ * task_participate_group_stop - participate in a group stop
+ * @task: task participating in a group stop
+ *
+ * @task has %JOBCTL_STOP_PENDING set and is participating in a group stop.
+ * Group stop states are cleared and the group stop count is consumed if
+ * %JOBCTL_STOP_CONSUME was set. If the consumption completes the group
+ * stop, the appropriate %SIGNAL_* flags are set.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ *
+ * RETURNS:
+ * %true if group stop completion should be notified to the parent, %false
+ * otherwise.
+ */
+static bool task_participate_group_stop(struct task_struct *task)
+{
+ struct signal_struct *sig = task->signal;
+ bool consume = task->jobctl & JOBCTL_STOP_CONSUME;
+
+ WARN_ON_ONCE(!(task->jobctl & JOBCTL_STOP_PENDING));
+
+ task_clear_jobctl_pending(task, JOBCTL_STOP_PENDING);
+
+ if (!consume)
+ return false;
+
+ if (!WARN_ON_ONCE(sig->group_stop_count == 0))
+ sig->group_stop_count--;
+
+ /*
+ * Tell the caller to notify completion iff we are entering into a
+ * fresh group stop. Read comment in do_signal_stop() for details.
+ */
+ if (!sig->group_stop_count && !(sig->flags & SIGNAL_STOP_STOPPED)) {
+ sig->flags = SIGNAL_STOP_STOPPED;
+ return true;
+ }
+ return false;
+}
+
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
- * appopriate lock must be held to stop the target task from exiting
+ * appropriate lock must be held to stop the target task from exiting
*/
static struct sigqueue *
__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
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
+ * Protect access to @t credentials. This can go away when all
+ * callers hold rcu read lock.
*/
+ rcu_read_lock();
user = get_uid(__task_cred(t)->user);
atomic_inc(&user->sigpending);
+ rcu_read_unlock();
if (override_rlimit ||
atomic_read(&user->sigpending) <=
- t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) {
+ task_rlimit(t, RLIMIT_SIGPENDING)) {
q = kmem_cache_alloc(sigqueue_cachep, flags);
} else {
print_dropped_signal(sig);
return 1;
if (handler != SIG_IGN && handler != SIG_DFL)
return 0;
- return !tracehook_consider_fatal_signal(tsk, sig);
+ /* if ptraced, let the tracer determine */
+ return !tsk->ptrace;
}
-
-/* Notify the system that a driver wants to block all signals for this
+/*
+ * Notify the system that a driver wants to block all signals for this
* process, and wants to be notified if any signals at all were to be
* sent/acted upon. If the notifier routine returns non-zero, then the
* signal will be acted upon after all. If the notifier routine returns 0,
* then then signal will be blocked. Only one block per process is
* allowed. priv is a pointer to private data that the notifier routine
- * can use to determine if the signal should be blocked or not. */
-
+ * can use to determine if the signal should be blocked or not.
+ */
void
block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
{
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.
+ /*
+ * 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;
}
/*
- * Dequeue a signal and return the element to the caller, which is
+ * Dequeue a signal and return the element to the caller, which is
* expected to free it.
*
* All callers have to hold the siglock.
* 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
+ * 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
* is to alert stop-signal processing code when another
* processor has come along and cleared the flag.
*/
- tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+ current->jobctl |= JOBCTL_STOP_DEQUEUED;
}
if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
/*
if (sigisemptyset(&m))
return 0;
- signandsets(&s->signal, &s->signal, mask);
+ sigandnsets(&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);
}
/*
+ * called with RCU read lock from check_kill_permission()
+ */
+static int kill_ok_by_cred(struct task_struct *t)
+{
+ const struct cred *cred = current_cred();
+ const struct cred *tcred = __task_cred(t);
+
+ if (cred->user->user_ns == tcred->user->user_ns &&
+ (cred->euid == tcred->suid ||
+ cred->euid == tcred->uid ||
+ cred->uid == tcred->suid ||
+ cred->uid == tcred->uid))
+ return 1;
+
+ if (ns_capable(tcred->user->user_ns, CAP_KILL))
+ return 1;
+
+ return 0;
+}
+
+/*
* Bad permissions for sending the signal
- * - the caller must hold at least the RCU read lock
+ * - the caller must hold the RCU read lock
*/
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 (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)) {
+ if (!same_thread_group(current, t) &&
+ !kill_ok_by_cred(t)) {
switch (sig) {
case SIGCONT:
sid = task_session(t);
return security_task_kill(t, info, sig, 0);
}
+/**
+ * ptrace_trap_notify - schedule trap to notify ptracer
+ * @t: tracee wanting to notify tracer
+ *
+ * This function schedules sticky ptrace trap which is cleared on the next
+ * TRAP_STOP to notify ptracer of an event. @t must have been seized by
+ * ptracer.
+ *
+ * If @t is running, STOP trap will be taken. If trapped for STOP and
+ * ptracer is listening for events, tracee is woken up so that it can
+ * re-trap for the new event. If trapped otherwise, STOP trap will be
+ * eventually taken without returning to userland after the existing traps
+ * are finished by PTRACE_CONT.
+ *
+ * CONTEXT:
+ * Must be called with @task->sighand->siglock held.
+ */
+static void ptrace_trap_notify(struct task_struct *t)
+{
+ WARN_ON_ONCE(!(t->ptrace & PT_SEIZED));
+ assert_spin_locked(&t->sighand->siglock);
+
+ task_set_jobctl_pending(t, JOBCTL_TRAP_NOTIFY);
+ signal_wake_up(t, t->jobctl & JOBCTL_LISTENING);
+}
+
/*
* Handle magic process-wide effects of stop/continue signals. Unlike
* the signal actions, these happen immediately at signal-generation
* Returns true if the signal should be actually delivered, otherwise
* it should be dropped.
*/
-static int prepare_signal(int sig, struct task_struct *p, int from_ancestor_ns)
+static int prepare_signal(int sig, struct task_struct *p, bool force)
{
struct signal_struct *signal = p->signal;
struct task_struct *t;
} else if (sig == SIGCONT) {
unsigned int why;
/*
- * Remove all stop signals from all queues,
- * and wake all threads.
+ * Remove all stop signals from all queues, wake all threads.
*/
rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
t = p;
do {
- unsigned int state;
+ task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
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);
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ wake_up_state(t, __TASK_STOPPED);
+ else
+ ptrace_trap_notify(t);
} while_each_thread(p, t);
/*
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);
+ return !sig_ignored(p, sig, force);
}
/*
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))) {
+ (sig == SIGKILL || !t->ptrace)) {
/*
* This signal will be fatal to the whole group.
*/
signal->group_stop_count = 0;
t = p;
do {
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
sigaddset(&t->pending.signal, SIGKILL);
signal_wake_up(t, 1);
} while_each_thread(p, t);
return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
}
+/*
+ * map the uid in struct cred into user namespace *ns
+ */
+static inline uid_t map_cred_ns(const struct cred *cred,
+ struct user_namespace *ns)
+{
+ return user_ns_map_uid(ns, cred, cred->uid);
+}
+
+#ifdef CONFIG_USER_NS
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+ if (current_user_ns() == task_cred_xxx(t, user_ns))
+ return;
+
+ if (SI_FROMKERNEL(info))
+ return;
+
+ info->si_uid = user_ns_map_uid(task_cred_xxx(t, user_ns),
+ current_cred(), info->si_uid);
+}
+#else
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+ return;
+}
+#endif
+
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_signal_generate(sig, info, t);
+ int ret = 0, result;
assert_spin_locked(&t->sighand->siglock);
- if (!prepare_signal(sig, t, from_ancestor_ns))
- return 0;
+ result = TRACE_SIGNAL_IGNORED;
+ if (!prepare_signal(sig, t,
+ from_ancestor_ns || (info == SEND_SIG_FORCED)))
+ goto ret;
pending = group ? &t->signal->shared_pending : &t->pending;
/*
* exactly one non-rt signal, so that we can get more
* detailed information about the cause of the signal.
*/
+ result = TRACE_SIGNAL_ALREADY_PENDING;
if (legacy_queue(pending, sig))
- return 0;
+ goto ret;
+
+ result = TRACE_SIGNAL_DELIVERED;
/*
* 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. */
-
+ /*
+ * 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
q->info.si_pid = 0;
break;
}
+
+ userns_fixup_signal_uid(&q->info, t);
+
} else if (!is_si_special(info)) {
if (sig >= SIGRTMIN && info->si_code != SI_USER) {
/*
* signal was rt and sent by user using something
* other than kill().
*/
- trace_signal_overflow_fail(sig, group, info);
- return -EAGAIN;
+ result = TRACE_SIGNAL_OVERFLOW_FAIL;
+ ret = -EAGAIN;
+ goto ret;
} else {
/*
* This is a silent loss of information. We still
* send the signal, but the *info bits are lost.
*/
- trace_signal_lose_info(sig, group, info);
+ result = TRACE_SIGNAL_LOSE_INFO;
}
}
signalfd_notify(t, sig);
sigaddset(&pending->signal, sig);
complete_signal(sig, t, group);
- return 0;
+ret:
+ trace_signal_generate(sig, info, t, group, result);
+ return ret;
}
static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
for (i = 0; i < 16; i++) {
unsigned char insn;
- __get_user(insn, (unsigned char *)(regs->ip + i));
+ if (get_user(insn, (unsigned char *)(regs->ip + i)))
+ break;
printk("%02x ", insn);
}
}
/*
* Nuke all other threads in the group.
*/
-void zap_other_threads(struct task_struct *p)
+int zap_other_threads(struct task_struct *p)
{
- struct task_struct *t;
+ struct task_struct *t = p;
+ int count = 0;
p->signal->group_stop_count = 0;
- for (t = next_thread(p); t != p; t = next_thread(t)) {
- /*
- * Don't bother with already dead threads
- */
+ while_each_thread(p, t) {
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+ count++;
+
+ /* 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);
}
+
+ return count;
}
-struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
+struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
+ unsigned long *flags)
{
struct sighand_struct *sighand;
- rcu_read_lock();
for (;;) {
+ local_irq_save(*flags);
+ rcu_read_lock();
sighand = rcu_dereference(tsk->sighand);
- if (unlikely(sighand == NULL))
+ if (unlikely(sighand == NULL)) {
+ rcu_read_unlock();
+ local_irq_restore(*flags);
break;
+ }
- spin_lock_irqsave(&sighand->siglock, *flags);
- if (likely(sighand == tsk->sighand))
+ spin_lock(&sighand->siglock);
+ if (likely(sighand == tsk->sighand)) {
+ rcu_read_unlock();
break;
- spin_unlock_irqrestore(&sighand->siglock, *flags);
+ }
+ spin_unlock(&sighand->siglock);
+ rcu_read_unlock();
+ local_irq_restore(*flags);
}
- rcu_read_unlock();
return sighand;
}
/*
* send signal info to all the members of a group
- * - the caller must hold the RCU read lock at least
*/
int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
- int ret = check_kill_permission(sig, info, p);
+ int ret;
+
+ rcu_read_lock();
+ ret = check_kill_permission(sig, info, p);
+ rcu_read_unlock();
if (!ret && sig)
ret = do_send_sig_info(sig, info, p, true);
return error;
}
-int
-kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
{
int error;
rcu_read_lock();
return error;
}
+static int kill_as_cred_perm(const struct cred *cred,
+ struct task_struct *target)
+{
+ const struct cred *pcred = __task_cred(target);
+ if (cred->user_ns != pcred->user_ns)
+ return 0;
+ if (cred->euid != pcred->suid && cred->euid != pcred->uid &&
+ cred->uid != pcred->suid && cred->uid != pcred->uid)
+ return 0;
+ return 1;
+}
+
/* like kill_pid_info(), but doesn't use uid/euid of "current" */
-int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid,
- uid_t uid, uid_t euid, u32 secid)
+int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
+ const struct cred *cred, u32 secid)
{
int ret = -EINVAL;
struct task_struct *p;
- const struct cred *pcred;
+ unsigned long flags;
if (!valid_signal(sig))
return ret;
- read_lock(&tasklist_lock);
+ rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (!p) {
ret = -ESRCH;
goto out_unlock;
}
- pcred = __task_cred(p);
- if (si_fromuser(info) &&
- euid != pcred->suid && euid != pcred->uid &&
- uid != pcred->suid && uid != pcred->uid) {
+ if (si_fromuser(info) && !kill_as_cred_perm(cred, p)) {
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);
+
+ if (sig) {
+ if (lock_task_sighand(p, &flags)) {
+ ret = __send_signal(sig, info, p, 1, 0);
+ unlock_task_sighand(p, &flags);
+ } else
+ ret = -ESRCH;
}
out_unlock:
- read_unlock(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}
-EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
+EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
/*
* kill_something_info() interprets pid in interesting ways just like kill(2).
* These are for backward compatibility with the rest of the kernel source.
*/
-int
-send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
/*
* Make sure legacy kernel users don't send in bad values
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
* afford to lose notifications of asynchronous events, like timer
- * expirations or I/O completions". In the case of Posix Timers
+ * expirations or I/O completions". In the case of POSIX Timers
* we allocate the sigqueue structure from the timer_create. If this
* allocation fails we are able to report the failure to the application
* with an EAGAIN error.
int sig = q->info.si_signo;
struct sigpending *pending;
unsigned long flags;
- int ret;
+ int ret, result;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
goto ret;
ret = 1; /* the signal is ignored */
- if (!prepare_signal(sig, t, 0))
+ result = TRACE_SIGNAL_IGNORED;
+ if (!prepare_signal(sig, t, false))
goto out;
ret = 0;
*/
BUG_ON(q->info.si_code != SI_TIMER);
q->info.si_overrun++;
+ result = TRACE_SIGNAL_ALREADY_PENDING;
goto out;
}
q->info.si_overrun = 0;
list_add_tail(&q->list, &pending->list);
sigaddset(&pending->signal, sig);
complete_signal(sig, t, group);
+ result = TRACE_SIGNAL_DELIVERED;
out:
+ trace_signal_generate(sig, &q->info, t, group, result);
unlock_task_sighand(t, &flags);
ret:
return ret;
* Let a parent know about the death of a child.
* For a stopped/continued status change, use do_notify_parent_cldstop instead.
*
- * Returns -1 if our parent ignored us and so we've switched to
- * self-reaping, or else @sig.
+ * Returns true if our parent ignored us and so we've switched to
+ * self-reaping.
*/
-int do_notify_parent(struct task_struct *tsk, int sig)
+bool do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
unsigned long flags;
struct sighand_struct *psig;
- int ret = sig;
+ bool autoreap = false;
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) &&
+ BUG_ON(!tsk->ptrace &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
+ if (sig != SIGCHLD) {
+ /*
+ * This is only possible if parent == real_parent.
+ * Check if it has changed security domain.
+ */
+ if (tsk->parent_exec_id != tsk->parent->self_exec_id)
+ sig = SIGCHLD;
+ }
+
info.si_signo = sig;
info.si_errno = 0;
/*
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
- info.si_uid = __task_cred(tsk)->uid;
+ info.si_uid = map_cred_ns(__task_cred(tsk),
+ task_cred_xxx(tsk->parent, user_ns));
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_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime);
+ info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime);
info.si_status = tsk->exit_code & 0x7f;
if (tsk->exit_code & 0x80)
psig = tsk->parent->sighand;
spin_lock_irqsave(&psig->siglock, flags);
- if (!task_ptrace(tsk) && sig == SIGCHLD &&
+ if (!tsk->ptrace && sig == SIGCHLD &&
(psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN ||
(psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) {
/*
* is implementation-defined: we do (if you don't want
* it, just use SIG_IGN instead).
*/
- ret = tsk->exit_signal = -1;
+ autoreap = true;
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
- sig = -1;
+ sig = 0;
}
- if (valid_signal(sig) && sig > 0)
+ if (valid_signal(sig) && sig)
__group_send_sig_info(sig, &info, tsk->parent);
__wake_up_parent(tsk, tsk->parent);
spin_unlock_irqrestore(&psig->siglock, flags);
- return ret;
+ return autoreap;
}
-static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
+/**
+ * do_notify_parent_cldstop - notify parent of stopped/continued state change
+ * @tsk: task reporting the state change
+ * @for_ptracer: the notification is for ptracer
+ * @why: CLD_{CONTINUED|STOPPED|TRAPPED} to report
+ *
+ * Notify @tsk's parent that the stopped/continued state has changed. If
+ * @for_ptracer is %false, @tsk's group leader notifies to its real parent.
+ * If %true, @tsk reports to @tsk->parent which should be the ptracer.
+ *
+ * CONTEXT:
+ * Must be called with tasklist_lock at least read locked.
+ */
+static void do_notify_parent_cldstop(struct task_struct *tsk,
+ bool for_ptracer, int why)
{
struct siginfo info;
unsigned long flags;
struct task_struct *parent;
struct sighand_struct *sighand;
- if (task_ptrace(tsk))
+ if (for_ptracer) {
parent = tsk->parent;
- else {
+ } 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
+ * see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
- info.si_uid = __task_cred(tsk)->uid;
+ info.si_uid = map_cred_ns(__task_cred(tsk),
+ task_cred_xxx(parent, user_ns));
rcu_read_unlock();
info.si_utime = cputime_to_clock_t(tsk->utime);
static inline int may_ptrace_stop(void)
{
- if (!likely(task_ptrace(current)))
+ if (!likely(current->ptrace))
return 0;
/*
* Are we in the middle of do_coredump?
}
/*
- * Return nonzero if there is a SIGKILL that should be waking us up.
+ * Return non-zero if there is a SIGKILL that should be waking us up.
* Called with the siglock held.
*/
static int sigkill_pending(struct task_struct *tsk)
* If we actually decide not to stop at all because the tracer
* is gone, we keep current->exit_code unless clear_code.
*/
-static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
+static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
+ __releases(¤t->sighand->siglock)
+ __acquires(¤t->sighand->siglock)
{
+ bool gstop_done = false;
+
if (arch_ptrace_stop_needed(exit_code, info)) {
/*
* The arch code has something special to do before a
}
/*
- * If there is a group stop in progress,
- * we must participate in the bookkeeping.
+ * We're committing to trapping. TRACED should be visible before
+ * TRAPPING is cleared; otherwise, the tracer might fail do_wait().
+ * Also, transition to TRACED and updates to ->jobctl should be
+ * atomic with respect to siglock and should be done after the arch
+ * hook as siglock is released and regrabbed across it.
*/
- if (current->signal->group_stop_count > 0)
- --current->signal->group_stop_count;
+ set_current_state(TASK_TRACED);
current->last_siginfo = info;
current->exit_code = exit_code;
- /* Let the debugger run. */
- __set_current_state(TASK_TRACED);
+ /*
+ * If @why is CLD_STOPPED, we're trapping to participate in a group
+ * stop. Do the bookkeeping. Note that if SIGCONT was delievered
+ * across siglock relocks since INTERRUPT was scheduled, PENDING
+ * could be clear now. We act as if SIGCONT is received after
+ * TASK_TRACED is entered - ignore it.
+ */
+ if (why == CLD_STOPPED && (current->jobctl & JOBCTL_STOP_PENDING))
+ gstop_done = task_participate_group_stop(current);
+
+ /* any trap clears pending STOP trap, STOP trap clears NOTIFY */
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ if (info && info->si_code >> 8 == PTRACE_EVENT_STOP)
+ task_clear_jobctl_pending(current, JOBCTL_TRAP_NOTIFY);
+
+ /* entering a trap, clear TRAPPING */
+ task_clear_jobctl_trapping(current);
+
spin_unlock_irq(¤t->sighand->siglock);
read_lock(&tasklist_lock);
if (may_ptrace_stop()) {
- do_notify_parent_cldstop(current, CLD_TRAPPED);
+ /*
+ * Notify parents of the stop.
+ *
+ * While ptraced, there are two parents - the ptracer and
+ * the real_parent of the group_leader. The ptracer should
+ * know about every stop while the real parent is only
+ * interested in the completion of group stop. The states
+ * for the two don't interact with each other. Notify
+ * separately unless they're gonna be duplicates.
+ */
+ do_notify_parent_cldstop(current, true, why);
+ if (gstop_done && ptrace_reparented(current))
+ do_notify_parent_cldstop(current, false, why);
+
/*
* Don't want to allow preemption here, because
* sys_ptrace() needs this task to be inactive.
/*
* By the time we got the lock, our tracer went away.
* Don't drop the lock yet, another tracer may come.
+ *
+ * If @gstop_done, the ptracer went away between group stop
+ * completion and here. During detach, it would have set
+ * JOBCTL_STOP_PENDING on us and we'll re-enter
+ * TASK_STOPPED in do_signal_stop() on return, so notifying
+ * the real parent of the group stop completion is enough.
*/
+ if (gstop_done)
+ do_notify_parent_cldstop(current, false, why);
+
__set_current_state(TASK_RUNNING);
if (clear_code)
current->exit_code = 0;
spin_lock_irq(¤t->sighand->siglock);
current->last_siginfo = NULL;
+ /* LISTENING can be set only during STOP traps, clear it */
+ current->jobctl &= ~JOBCTL_LISTENING;
+
/*
* Queued signals ignored us while we were stopped for tracing.
* So check for any that we should take before resuming user mode.
recalc_sigpending_tsk(current);
}
-void ptrace_notify(int exit_code)
+static void ptrace_do_notify(int signr, int exit_code, int why)
{
siginfo_t info;
- BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
-
memset(&info, 0, sizeof info);
- info.si_signo = SIGTRAP;
+ info.si_signo = signr;
info.si_code = exit_code;
info.si_pid = task_pid_vnr(current);
info.si_uid = current_uid();
/* Let the debugger run. */
+ ptrace_stop(exit_code, why, 1, &info);
+}
+
+void ptrace_notify(int exit_code)
+{
+ BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
spin_lock_irq(¤t->sighand->siglock);
- ptrace_stop(exit_code, 1, &info);
+ ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
spin_unlock_irq(¤t->sighand->siglock);
}
-/*
- * This performs the stopping for SIGSTOP and other stop signals.
- * We have to stop all threads in the thread group.
- * Returns nonzero if we've actually stopped and released the siglock.
- * Returns zero if we didn't stop and still hold the siglock.
+/**
+ * do_signal_stop - handle group stop for SIGSTOP and other stop signals
+ * @signr: signr causing group stop if initiating
+ *
+ * If %JOBCTL_STOP_PENDING is not set yet, initiate group stop with @signr
+ * and participate in it. If already set, participate in the existing
+ * group stop. If participated in a group stop (and thus slept), %true is
+ * returned with siglock released.
+ *
+ * If ptraced, this function doesn't handle stop itself. Instead,
+ * %JOBCTL_TRAP_STOP is scheduled and %false is returned with siglock
+ * untouched. The caller must ensure that INTERRUPT trap handling takes
+ * places afterwards.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which is released
+ * on %true return.
+ *
+ * RETURNS:
+ * %false if group stop is already cancelled or ptrace trap is scheduled.
+ * %true if participated in group stop.
*/
-static int do_signal_stop(int signr)
+static bool do_signal_stop(int signr)
+ __releases(¤t->sighand->siglock)
{
struct signal_struct *sig = current->signal;
- int notify;
- if (!sig->group_stop_count) {
+ if (!(current->jobctl & JOBCTL_STOP_PENDING)) {
+ unsigned int gstop = JOBCTL_STOP_PENDING | JOBCTL_STOP_CONSUME;
struct task_struct *t;
- if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
+ /* signr will be recorded in task->jobctl for retries */
+ WARN_ON_ONCE(signr & ~JOBCTL_STOP_SIGMASK);
+
+ if (!likely(current->jobctl & JOBCTL_STOP_DEQUEUED) ||
unlikely(signal_group_exit(sig)))
- return 0;
+ return false;
/*
- * There is no group stop already in progress.
- * We must initiate one now.
+ * There is no group stop already in progress. We must
+ * initiate one now.
+ *
+ * While ptraced, a task may be resumed while group stop is
+ * still in effect and then receive a stop signal and
+ * initiate another group stop. This deviates from the
+ * usual behavior as two consecutive stop signals can't
+ * cause two group stops when !ptraced. That is why we
+ * also check !task_is_stopped(t) below.
+ *
+ * The condition can be distinguished by testing whether
+ * SIGNAL_STOP_STOPPED is already set. Don't generate
+ * group_exit_code in such case.
+ *
+ * This is not necessary for SIGNAL_STOP_CONTINUED because
+ * an intervening stop signal is required to cause two
+ * continued events regardless of ptrace.
*/
- sig->group_exit_code = signr;
+ if (!(sig->flags & SIGNAL_STOP_STOPPED))
+ sig->group_exit_code = signr;
+
+ sig->group_stop_count = 0;
+
+ if (task_set_jobctl_pending(current, signr | gstop))
+ sig->group_stop_count++;
- sig->group_stop_count = 1;
- for (t = next_thread(current); t != current; t = next_thread(t))
+ 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)) {
+ if (!task_is_stopped(t) &&
+ task_set_jobctl_pending(t, signr | gstop)) {
sig->group_stop_count++;
- signal_wake_up(t, 0);
+ if (likely(!(t->ptrace & PT_SEIZED)))
+ signal_wake_up(t, 0);
+ else
+ ptrace_trap_notify(t);
}
+ }
}
- /*
- * 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.
- */
- notify = sig->group_stop_count == 1 ? CLD_STOPPED : 0;
- notify = tracehook_notify_jctl(notify, CLD_STOPPED);
- /*
- * tracehook_notify_jctl() can drop and reacquire siglock, so
- * we keep ->group_stop_count != 0 before the call. If SIGCONT
- * or SIGKILL comes in between ->group_stop_count == 0.
- */
- if (sig->group_stop_count) {
- if (!--sig->group_stop_count)
- sig->flags = SIGNAL_STOP_STOPPED;
- current->exit_code = sig->group_exit_code;
+
+ if (likely(!current->ptrace)) {
+ int notify = 0;
+
+ /*
+ * 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.
+ */
+ if (task_participate_group_stop(current))
+ notify = CLD_STOPPED;
+
__set_current_state(TASK_STOPPED);
- }
- spin_unlock_irq(¤t->sighand->siglock);
+ spin_unlock_irq(¤t->sighand->siglock);
- if (notify) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current, notify);
- read_unlock(&tasklist_lock);
- }
+ /*
+ * Notify the parent of the group stop completion. Because
+ * we're not holding either the siglock or tasklist_lock
+ * here, ptracer may attach inbetween; however, this is for
+ * group stop and should always be delivered to the real
+ * parent of the group leader. The new ptracer will get
+ * its notification when this task transitions into
+ * TASK_TRACED.
+ */
+ if (notify) {
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, false, notify);
+ read_unlock(&tasklist_lock);
+ }
- /* Now we don't run again until woken by SIGCONT or SIGKILL */
- do {
+ /* Now we don't run again until woken by SIGCONT or SIGKILL */
schedule();
- } while (try_to_freeze());
-
- tracehook_finish_jctl();
- current->exit_code = 0;
+ return true;
+ } else {
+ /*
+ * While ptraced, group stop is handled by STOP trap.
+ * Schedule it and let the caller deal with it.
+ */
+ task_set_jobctl_pending(current, JOBCTL_TRAP_STOP);
+ return false;
+ }
+}
- return 1;
+/**
+ * do_jobctl_trap - take care of ptrace jobctl traps
+ *
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo. If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
+ *
+ * CONTEXT:
+ * Must be called with @current->sighand->siglock held, which may be
+ * released and re-acquired before returning with intervening sleep.
+ */
+static void do_jobctl_trap(void)
+{
+ struct signal_struct *signal = current->signal;
+ int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
+
+ if (current->ptrace & PT_SEIZED) {
+ if (!signal->group_stop_count &&
+ !(signal->flags & SIGNAL_STOP_STOPPED))
+ signr = SIGTRAP;
+ WARN_ON_ONCE(!signr);
+ ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+ CLD_STOPPED);
+ } else {
+ WARN_ON_ONCE(!signr);
+ ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+ current->exit_code = 0;
+ }
}
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 do not check sig_kernel_stop(signr) but set this marker
+ * unconditionally because we do not know whether debugger will
+ * change signr. This flag has no meaning unless we are going
+ * to stop after return from ptrace_stop(). In this case it will
+ * be checked in do_signal_stop(), we should only stop if it was
+ * not cleared by SIGCONT while we were sleeping. See also the
+ * comment in dequeue_signal().
+ */
+ current->jobctl |= JOBCTL_STOP_DEQUEUED;
+ ptrace_stop(signr, CLD_TRAPPED, 0, info);
/* We're back. Did the debugger cancel the sig? */
signr = current->exit_code;
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. */
+ /*
+ * 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;
+ rcu_read_lock();
info->si_pid = task_pid_vnr(current->parent);
- info->si_uid = task_uid(current->parent);
+ info->si_uid = map_cred_ns(__task_cred(current->parent),
+ current_user_ns());
+ rcu_read_unlock();
}
/* If the (new) signal is now blocked, requeue it. */
* 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;
+ int why;
+
+ if (signal->flags & SIGNAL_CLD_CONTINUED)
+ why = CLD_CONTINUED;
+ else
+ why = CLD_STOPPED;
+
signal->flags &= ~SIGNAL_CLD_MASK;
- why = tracehook_notify_jctl(why, CLD_CONTINUED);
spin_unlock_irq(&sighand->siglock);
- if (why) {
- read_lock(&tasklist_lock);
- do_notify_parent_cldstop(current->group_leader, why);
- read_unlock(&tasklist_lock);
- }
+ /*
+ * Notify the parent that we're continuing. This event is
+ * always per-process and doesn't make whole lot of sense
+ * for ptracers, who shouldn't consume the state via
+ * wait(2) either, but, for backward compatibility, notify
+ * the ptracer of the group leader too unless it's gonna be
+ * a duplicate.
+ */
+ read_lock(&tasklist_lock);
+ do_notify_parent_cldstop(current, false, why);
+
+ if (ptrace_reparented(current->group_leader))
+ do_notify_parent_cldstop(current->group_leader,
+ true, why);
+ read_unlock(&tasklist_lock);
+
goto relock;
}
for (;;) {
struct k_sigaction *ka;
- if (unlikely(signal->group_stop_count > 0) &&
+ if (unlikely(current->jobctl & JOBCTL_STOP_PENDING) &&
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))
+ if (unlikely(current->jobctl & JOBCTL_TRAP_MASK)) {
+ do_jobctl_trap();
+ spin_unlock_irq(&sighand->siglock);
goto relock;
- if (unlikely(signr != 0))
- ka = return_ka;
- else {
- signr = dequeue_signal(current, ¤t->blocked,
- info);
+ }
- if (!signr)
- break; /* will return 0 */
+ signr = dequeue_signal(current, ¤t->blocked, info);
- if (signr != SIGKILL) {
- signr = ptrace_signal(signr, info,
- regs, cookie);
- if (!signr)
- continue;
- }
+ if (!signr)
+ break; /* will return 0 */
- ka = &sighand->action[signr-1];
+ if (unlikely(current->ptrace) && signr != SIGKILL) {
+ signr = ptrace_signal(signr, info,
+ regs, cookie);
+ if (!signr)
+ continue;
}
+ ka = &sighand->action[signr-1];
+
/* Trace actually delivered signals. */
trace_signal_deliver(signr, info, ka);
return signr;
}
+/**
+ * block_sigmask - add @ka's signal mask to current->blocked
+ * @ka: action for @signr
+ * @signr: signal that has been successfully delivered
+ *
+ * This function should be called when a signal has succesfully been
+ * delivered. It adds the mask of signals for @ka to current->blocked
+ * so that they are blocked during the execution of the signal
+ * handler. In addition, @signr will be blocked unless %SA_NODEFER is
+ * set in @ka->sa.sa_flags.
+ */
+void block_sigmask(struct k_sigaction *ka, int signr)
+{
+ sigset_t blocked;
+
+ sigorsets(&blocked, ¤t->blocked, &ka->sa.sa_mask);
+ if (!(ka->sa.sa_flags & SA_NODEFER))
+ sigaddset(&blocked, signr);
+ set_current_blocked(&blocked);
+}
+
+/*
+ * It could be that complete_signal() picked us to notify about the
+ * group-wide signal. Other threads should be notified now to take
+ * the shared signals in @which since we will not.
+ */
+static void retarget_shared_pending(struct task_struct *tsk, sigset_t *which)
+{
+ sigset_t retarget;
+ struct task_struct *t;
+
+ sigandsets(&retarget, &tsk->signal->shared_pending.signal, which);
+ if (sigisemptyset(&retarget))
+ return;
+
+ t = tsk;
+ while_each_thread(tsk, t) {
+ if (t->flags & PF_EXITING)
+ continue;
+
+ if (!has_pending_signals(&retarget, &t->blocked))
+ continue;
+ /* Remove the signals this thread can handle. */
+ sigandsets(&retarget, &retarget, &t->blocked);
+
+ if (!signal_pending(t))
+ signal_wake_up(t, 0);
+
+ if (sigisemptyset(&retarget))
+ break;
+ }
+}
+
void exit_signals(struct task_struct *tsk)
{
int group_stop = 0;
- struct task_struct *t;
+ sigset_t unblocked;
+
+ /*
+ * @tsk is about to have PF_EXITING set - lock out users which
+ * expect stable threadgroup.
+ */
+ threadgroup_change_begin(tsk);
if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
tsk->flags |= PF_EXITING;
+ threadgroup_change_end(tsk);
return;
}
* see wants_signal(), do_signal_stop().
*/
tsk->flags |= PF_EXITING;
+
+ threadgroup_change_end(tsk);
+
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);
+ unblocked = tsk->blocked;
+ signotset(&unblocked);
+ retarget_shared_pending(tsk, &unblocked);
- if (unlikely(tsk->signal->group_stop_count) &&
- !--tsk->signal->group_stop_count) {
- tsk->signal->flags = SIGNAL_STOP_STOPPED;
- group_stop = tracehook_notify_jctl(CLD_STOPPED, CLD_STOPPED);
- }
+ if (unlikely(tsk->jobctl & JOBCTL_STOP_PENDING) &&
+ task_participate_group_stop(tsk))
+ group_stop = CLD_STOPPED;
out:
spin_unlock_irq(&tsk->sighand->siglock);
+ /*
+ * If group stop has completed, deliver the notification. This
+ * should always go to the real parent of the group leader.
+ */
if (unlikely(group_stop)) {
read_lock(&tasklist_lock);
- do_notify_parent_cldstop(tsk, group_stop);
+ do_notify_parent_cldstop(tsk, false, group_stop);
read_unlock(&tasklist_lock);
}
}
* System call entry points.
*/
+/**
+ * sys_restart_syscall - restart a system call
+ */
SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = ¤t_thread_info()->restart_block;
return -EINTR;
}
-/*
- * We don't need to get the kernel lock - this is all local to this
- * particular thread.. (and that's good, because this is _heavily_
- * used by various programs)
+static void __set_task_blocked(struct task_struct *tsk, const sigset_t *newset)
+{
+ if (signal_pending(tsk) && !thread_group_empty(tsk)) {
+ sigset_t newblocked;
+ /* A set of now blocked but previously unblocked signals. */
+ sigandnsets(&newblocked, newset, ¤t->blocked);
+ retarget_shared_pending(tsk, &newblocked);
+ }
+ tsk->blocked = *newset;
+ recalc_sigpending();
+}
+
+/**
+ * set_current_blocked - change current->blocked mask
+ * @newset: new mask
+ *
+ * It is wrong to change ->blocked directly, this helper should be used
+ * to ensure the process can't miss a shared signal we are going to block.
*/
+void set_current_blocked(const sigset_t *newset)
+{
+ struct task_struct *tsk = current;
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, newset);
+ spin_unlock_irq(&tsk->sighand->siglock);
+}
/*
* This is also useful for kernel threads that want to temporarily
*/
int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
{
- int error;
+ struct task_struct *tsk = current;
+ sigset_t newset;
- spin_lock_irq(¤t->sighand->siglock);
+ /* Lockless, only current can change ->blocked, never from irq */
if (oldset)
- *oldset = current->blocked;
+ *oldset = tsk->blocked;
- error = 0;
switch (how) {
case SIG_BLOCK:
- sigorsets(¤t->blocked, ¤t->blocked, set);
+ sigorsets(&newset, &tsk->blocked, set);
break;
case SIG_UNBLOCK:
- signandsets(¤t->blocked, ¤t->blocked, set);
+ sigandnsets(&newset, &tsk->blocked, set);
break;
case SIG_SETMASK:
- current->blocked = *set;
+ newset = *set;
break;
default:
- error = -EINVAL;
+ return -EINVAL;
}
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- return error;
+ set_current_blocked(&newset);
+ return 0;
}
-SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
+/**
+ * sys_rt_sigprocmask - change the list of currently blocked signals
+ * @how: whether to add, remove, or set signals
+ * @nset: stores pending signals
+ * @oset: previous value of signal mask if non-null
+ * @sigsetsize: size of sigset_t type
+ */
+SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, nset,
sigset_t __user *, oset, size_t, sigsetsize)
{
- int error = -EINVAL;
sigset_t old_set, new_set;
+ int error;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
- goto out;
+ return -EINVAL;
- if (set) {
- error = -EFAULT;
- if (copy_from_user(&new_set, set, sizeof(*set)))
- goto out;
+ old_set = current->blocked;
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(sigset_t)))
+ return -EFAULT;
sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
- error = sigprocmask(how, &new_set, &old_set);
+ error = sigprocmask(how, &new_set, NULL);
if (error)
- goto out;
- if (oset)
- goto set_old;
- } else if (oset) {
- spin_lock_irq(¤t->sighand->siglock);
- old_set = current->blocked;
- spin_unlock_irq(¤t->sighand->siglock);
+ return error;
+ }
- set_old:
- error = -EFAULT;
- if (copy_to_user(oset, &old_set, sizeof(*oset)))
- goto out;
+ if (oset) {
+ if (copy_to_user(oset, &old_set, sizeof(sigset_t)))
+ return -EFAULT;
}
- error = 0;
-out:
- return error;
+
+ return 0;
}
long do_sigpending(void __user *set, unsigned long sigsetsize)
out:
return error;
-}
+}
+/**
+ * sys_rt_sigpending - examine a pending signal that has been raised
+ * while blocked
+ * @set: stores pending signals
+ * @sigsetsize: size of sigset_t type or larger
+ */
SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
return do_sigpending(set, sigsetsize);
#ifdef __ARCH_SI_TRAPNO
err |= __put_user(from->si_trapno, &to->si_trapno);
#endif
+#ifdef BUS_MCEERR_AO
+ /*
+ * Other callers might not initialize the si_lsb field,
+ * so check explicitly for the right codes here.
+ */
+ if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
+ err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
+#endif
break;
case __SI_CHLD:
err |= __put_user(from->si_pid, &to->si_pid);
#endif
+/**
+ * do_sigtimedwait - wait for queued signals specified in @which
+ * @which: queued signals to wait for
+ * @info: if non-null, the signal's siginfo is returned here
+ * @ts: upper bound on process time suspension
+ */
+int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
+ const struct timespec *ts)
+{
+ struct task_struct *tsk = current;
+ long timeout = MAX_SCHEDULE_TIMEOUT;
+ sigset_t mask = *which;
+ int sig;
+
+ if (ts) {
+ if (!timespec_valid(ts))
+ return -EINVAL;
+ timeout = timespec_to_jiffies(ts);
+ /*
+ * We can be close to the next tick, add another one
+ * to ensure we will wait at least the time asked for.
+ */
+ if (ts->tv_sec || ts->tv_nsec)
+ timeout++;
+ }
+
+ /*
+ * Invert the set of allowed signals to get those we want to block.
+ */
+ sigdelsetmask(&mask, sigmask(SIGKILL) | sigmask(SIGSTOP));
+ signotset(&mask);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ sig = dequeue_signal(tsk, &mask, info);
+ if (!sig && timeout) {
+ /*
+ * None ready, temporarily unblock those we're interested
+ * while we are sleeping in so that we'll be awakened when
+ * they arrive. Unblocking is always fine, we can avoid
+ * set_current_blocked().
+ */
+ tsk->real_blocked = tsk->blocked;
+ sigandsets(&tsk->blocked, &tsk->blocked, &mask);
+ recalc_sigpending();
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ timeout = schedule_timeout_interruptible(timeout);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+ __set_task_blocked(tsk, &tsk->real_blocked);
+ siginitset(&tsk->real_blocked, 0);
+ sig = dequeue_signal(tsk, &mask, info);
+ }
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (sig)
+ return sig;
+ return timeout ? -EINTR : -EAGAIN;
+}
+
+/**
+ * sys_rt_sigtimedwait - synchronously wait for queued signals specified
+ * in @uthese
+ * @uthese: queued signals to wait for
+ * @uinfo: if non-null, the signal's siginfo is returned here
+ * @uts: upper bound on process time suspension
+ * @sigsetsize: size of sigset_t type
+ */
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;
+ int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
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(¤t->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(¤t->blocked, ¤t->blocked, &these);
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
-
- timeout = schedule_timeout_interruptible(timeout);
-
- spin_lock_irq(¤t->sighand->siglock);
- sig = dequeue_signal(current, &these, &info);
- current->blocked = current->real_blocked;
- siginitset(¤t->real_blocked, 0);
- recalc_sigpending();
- }
- }
- spin_unlock_irq(¤t->sighand->siglock);
+ ret = do_sigtimedwait(&these, &info, uts ? &ts : NULL);
- if (sig) {
- ret = sig;
- if (uinfo) {
- if (copy_siginfo_to_user(uinfo, &info))
- ret = -EFAULT;
- }
- } else {
- ret = -EAGAIN;
- if (timeout)
- ret = -EINTR;
+ if (ret > 0 && uinfo) {
+ if (copy_siginfo_to_user(uinfo, &info))
+ ret = -EFAULT;
}
return ret;
}
+/**
+ * sys_kill - send a signal to a process
+ * @pid: the PID of the process
+ * @sig: signal to be sent
+ */
SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct siginfo info;
return do_tkill(tgid, pid, sig);
}
-/*
+/**
+ * sys_tkill - send signal to one specific task
+ * @pid: the PID of the task
+ * @sig: signal to be sent
+ *
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
return do_tkill(0, pid, sig);
}
+/**
+ * sys_rt_sigqueueinfo - send signal information to a signal
+ * @pid: the PID of the thread
+ * @sig: signal to be sent
+ * @uinfo: signal info to be sent
+ */
SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
siginfo_t __user *, uinfo)
{
return -EFAULT;
/* Not even root can pretend to send signals from the kernel.
- Nor can they impersonate a kill(), which adds source info. */
- if (info.si_code >= 0)
+ * Nor can they impersonate a kill()/tgkill(), which adds source info.
+ */
+ if (info.si_code >= 0 || info.si_code == SI_TKILL) {
+ /* We used to allow any < 0 si_code */
+ WARN_ON_ONCE(info.si_code < 0);
return -EPERM;
+ }
info.si_signo = sig;
/* POSIX.1b doesn't mention process groups. */
return -EINVAL;
/* Not even root can pretend to send signals from the kernel.
- Nor can they impersonate a kill(), which adds source info. */
- if (info->si_code >= 0)
+ * Nor can they impersonate a kill()/tgkill(), which adds source info.
+ */
+ if (info->si_code >= 0 || info->si_code == SI_TKILL) {
+ /* We used to allow any < 0 si_code */
+ WARN_ON_ONCE(info->si_code < 0);
return -EPERM;
+ }
info->si_signo = sig;
return do_send_specific(tgid, pid, sig, info);
error = -EINVAL;
/*
- *
- * Note - this code used to test ss_flags incorrectly
+ * 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
+ * mechanism.
*/
if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
goto out;
#ifdef __ARCH_WANT_SYS_SIGPENDING
+/**
+ * sys_sigpending - examine pending signals
+ * @set: where mask of pending signal is returned
+ */
SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
return do_sigpending(set, sizeof(*set));
#endif
#ifdef __ARCH_WANT_SYS_SIGPROCMASK
-/* Some platforms have their own version with special arguments others
- support only sys_rt_sigprocmask. */
+/**
+ * sys_sigprocmask - examine and change blocked signals
+ * @how: whether to add, remove, or set signals
+ * @nset: signals to add or remove (if non-null)
+ * @oset: previous value of signal mask if non-null
+ *
+ * Some platforms have their own version with special arguments;
+ * others support only sys_rt_sigprocmask.
+ */
-SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
+SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, nset,
old_sigset_t __user *, oset)
{
- int error;
old_sigset_t old_set, new_set;
+ sigset_t new_blocked;
- if (set) {
- error = -EFAULT;
- if (copy_from_user(&new_set, set, sizeof(*set)))
- goto out;
+ old_set = current->blocked.sig[0];
+
+ if (nset) {
+ if (copy_from_user(&new_set, nset, sizeof(*nset)))
+ return -EFAULT;
new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP));
- spin_lock_irq(¤t->sighand->siglock);
- old_set = current->blocked.sig[0];
+ new_blocked = current->blocked;
- error = 0;
switch (how) {
- default:
- error = -EINVAL;
- break;
case SIG_BLOCK:
- sigaddsetmask(¤t->blocked, new_set);
+ sigaddsetmask(&new_blocked, new_set);
break;
case SIG_UNBLOCK:
- sigdelsetmask(¤t->blocked, new_set);
+ sigdelsetmask(&new_blocked, new_set);
break;
case SIG_SETMASK:
- current->blocked.sig[0] = new_set;
+ new_blocked.sig[0] = new_set;
break;
+ default:
+ return -EINVAL;
}
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
- if (error)
- goto out;
- if (oset)
- goto set_old;
- } else if (oset) {
- old_set = current->blocked.sig[0];
- set_old:
- error = -EFAULT;
+ set_current_blocked(&new_blocked);
+ }
+
+ if (oset) {
if (copy_to_user(oset, &old_set, sizeof(*oset)))
- goto out;
+ return -EFAULT;
}
- error = 0;
-out:
- return error;
+
+ return 0;
}
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifdef __ARCH_WANT_SYS_RT_SIGACTION
+/**
+ * sys_rt_sigaction - alter an action taken by a process
+ * @sig: signal to be sent
+ * @act: new sigaction
+ * @oact: used to save the previous sigaction
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigaction, int, sig,
const struct sigaction __user *, act,
struct sigaction __user *, oact,
SYSCALL_DEFINE1(ssetmask, int, newmask)
{
- int old;
+ int old = current->blocked.sig[0];
+ sigset_t newset;
- spin_lock_irq(¤t->sighand->siglock);
- old = current->blocked.sig[0];
-
- siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)|
- sigmask(SIGSTOP)));
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
+ siginitset(&newset, newmask & ~(sigmask(SIGKILL) | sigmask(SIGSTOP)));
+ set_current_blocked(&newset);
return old;
}
SYSCALL_DEFINE0(pause)
{
- current->state = TASK_INTERRUPTIBLE;
- schedule();
+ while (!signal_pending(current)) {
+ current->state = TASK_INTERRUPTIBLE;
+ schedule();
+ }
return -ERESTARTNOHAND;
}
#endif
#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
+/**
+ * sys_rt_sigsuspend - replace the signal mask for a value with the
+ * @unewset value until a signal is received
+ * @unewset: new signal mask value
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;
return -EFAULT;
sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
- spin_lock_irq(¤t->sighand->siglock);
current->saved_sigmask = current->blocked;
- current->blocked = newset;
- recalc_sigpending();
- spin_unlock_irq(¤t->sighand->siglock);
+ set_current_blocked(&newset);
current->state = TASK_INTERRUPTIBLE;
schedule();
{
sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
}
+
+#ifdef CONFIG_KGDB_KDB
+#include <linux/kdb.h>
+/*
+ * kdb_send_sig_info - Allows kdb to send signals without exposing
+ * signal internals. This function checks if the required locks are
+ * available before calling the main signal code, to avoid kdb
+ * deadlocks.
+ */
+void
+kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
+{
+ static struct task_struct *kdb_prev_t;
+ int sig, new_t;
+ if (!spin_trylock(&t->sighand->siglock)) {
+ kdb_printf("Can't do kill command now.\n"
+ "The sigmask lock is held somewhere else in "
+ "kernel, try again later\n");
+ return;
+ }
+ spin_unlock(&t->sighand->siglock);
+ new_t = kdb_prev_t != t;
+ kdb_prev_t = t;
+ if (t->state != TASK_RUNNING && new_t) {
+ kdb_printf("Process is not RUNNING, sending a signal from "
+ "kdb risks deadlock\n"
+ "on the run queue locks. "
+ "The signal has _not_ been sent.\n"
+ "Reissue the kill command if you want to risk "
+ "the deadlock.\n");
+ return;
+ }
+ sig = info->si_signo;
+ if (send_sig_info(sig, info, t))
+ kdb_printf("Fail to deliver Signal %d to process %d.\n",
+ sig, t->pid);
+ else
+ kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
+}
+#endif /* CONFIG_KGDB_KDB */
projects / linux-flexiantxendom0-3.2.10.git / blobdiff