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Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c138
1 files changed, 89 insertions, 49 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index c9c57d053c..7bdbcf1b78 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -47,6 +47,7 @@
#include <linux/cgroup.h>
#include <linux/audit.h>
#include <linux/sysctl.h>
+#include <uapi/linux/pidfd.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
@@ -1436,7 +1437,8 @@ void lockdep_assert_task_sighand_held(struct task_struct *task)
#endif
/*
- * send signal info to all the members of a group
+ * send signal info to all the members of a thread group or to the
+ * individual thread if type == PIDTYPE_PID.
*/
int group_send_sig_info(int sig, struct kernel_siginfo *info,
struct task_struct *p, enum pid_type type)
@@ -1478,7 +1480,8 @@ int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
return ret;
}
-int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
+static int kill_pid_info_type(int sig, struct kernel_siginfo *info,
+ struct pid *pid, enum pid_type type)
{
int error = -ESRCH;
struct task_struct *p;
@@ -1487,11 +1490,10 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
rcu_read_lock();
p = pid_task(pid, PIDTYPE_PID);
if (p)
- error = group_send_sig_info(sig, info, p, PIDTYPE_TGID);
+ error = group_send_sig_info(sig, info, p, type);
rcu_read_unlock();
if (likely(!p || error != -ESRCH))
return error;
-
/*
* The task was unhashed in between, try again. If it
* is dead, pid_task() will return NULL, if we race with
@@ -1500,6 +1502,11 @@ int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
}
}
+int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
+{
+ return kill_pid_info_type(sig, info, pid, PIDTYPE_TGID);
+}
+
static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
{
int error;
@@ -1898,16 +1905,19 @@ int send_sig_fault_trapno(int sig, int code, void __user *addr, int trapno,
return send_sig_info(info.si_signo, &info, t);
}
-int kill_pgrp(struct pid *pid, int sig, int priv)
+static int kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
{
int ret;
-
read_lock(&tasklist_lock);
- ret = __kill_pgrp_info(sig, __si_special(priv), pid);
+ ret = __kill_pgrp_info(sig, info, pgrp);
read_unlock(&tasklist_lock);
-
return ret;
}
+
+int kill_pgrp(struct pid *pid, int sig, int priv)
+{
+ return kill_pgrp_info(sig, __si_special(priv), pid);
+}
EXPORT_SYMBOL(kill_pgrp);
int kill_pid(struct pid *pid, int sig, int priv)
@@ -2019,13 +2029,14 @@ ret:
return ret;
}
-static void do_notify_pidfd(struct task_struct *task)
+void do_notify_pidfd(struct task_struct *task)
{
- struct pid *pid;
+ struct pid *pid = task_pid(task);
WARN_ON(task->exit_state == 0);
- pid = task_pid(task);
- wake_up_all(&pid->wait_pidfd);
+
+ __wake_up(&pid->wait_pidfd, TASK_NORMAL, 0,
+ poll_to_key(EPOLLIN | EPOLLRDNORM));
}
/*
@@ -2050,9 +2061,12 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
WARN_ON_ONCE(!tsk->ptrace &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
-
- /* Wake up all pidfd waiters */
- do_notify_pidfd(tsk);
+ /*
+ * tsk is a group leader and has no threads, wake up the
+ * non-PIDFD_THREAD waiters.
+ */
+ if (thread_group_empty(tsk))
+ do_notify_pidfd(tsk);
if (sig != SIGCHLD) {
/*
@@ -2727,12 +2741,15 @@ relock:
/* Has this task already been marked for death? */
if ((signal->flags & SIGNAL_GROUP_EXIT) ||
signal->group_exec_task) {
- clear_siginfo(&ksig->info);
- ksig->info.si_signo = signr = SIGKILL;
+ signr = SIGKILL;
sigdelset(&current->pending.signal, SIGKILL);
trace_signal_deliver(SIGKILL, SEND_SIG_NOINFO,
- &sighand->action[SIGKILL - 1]);
+ &sighand->action[SIGKILL-1]);
recalc_sigpending();
+ /*
+ * implies do_group_exit() or return to PF_USER_WORKER,
+ * no need to initialize ksig->info/etc.
+ */
goto fatal;
}
@@ -2842,7 +2859,7 @@ relock:
spin_lock_irq(&sighand->siglock);
}
- if (likely(do_signal_stop(ksig->info.si_signo))) {
+ if (likely(do_signal_stop(signr))) {
/* It released the siglock. */
goto relock;
}
@@ -2866,7 +2883,7 @@ relock:
if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
- print_fatal_signal(ksig->info.si_signo);
+ print_fatal_signal(signr);
proc_coredump_connector(current);
/*
* If it was able to dump core, this kills all
@@ -2881,8 +2898,9 @@ relock:
/*
* PF_USER_WORKER threads will catch and exit on fatal signals
- * themselves. They have cleanup that must be performed, so
- * we cannot call do_exit() on their behalf.
+ * themselves. They have cleanup that must be performed, so we
+ * cannot call do_exit() on their behalf. Note that ksig won't
+ * be properly initialized, PF_USER_WORKER's shouldn't use it.
*/
if (current->flags & PF_USER_WORKER)
goto out;
@@ -2890,17 +2908,17 @@ relock:
/*
* Death signals, no core dump.
*/
- do_group_exit(ksig->info.si_signo);
+ do_group_exit(signr);
/* NOTREACHED */
}
spin_unlock_irq(&sighand->siglock);
-out:
+
ksig->sig = signr;
- if (!(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
+ if (signr && !(ksig->ka.sa.sa_flags & SA_EXPOSE_TAGBITS))
hide_si_addr_tag_bits(ksig);
-
- return ksig->sig > 0;
+out:
+ return signr > 0;
}
/**
@@ -3789,12 +3807,13 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait_time32, compat_sigset_t __user *, uthese,
#endif
#endif
-static inline void prepare_kill_siginfo(int sig, struct kernel_siginfo *info)
+static void prepare_kill_siginfo(int sig, struct kernel_siginfo *info,
+ enum pid_type type)
{
clear_siginfo(info);
info->si_signo = sig;
info->si_errno = 0;
- info->si_code = SI_USER;
+ info->si_code = (type == PIDTYPE_PID) ? SI_TKILL : SI_USER;
info->si_pid = task_tgid_vnr(current);
info->si_uid = from_kuid_munged(current_user_ns(), current_uid());
}
@@ -3808,7 +3827,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct kernel_siginfo info;
- prepare_kill_siginfo(sig, &info);
+ prepare_kill_siginfo(sig, &info, PIDTYPE_TGID);
return kill_something_info(sig, &info, pid);
}
@@ -3861,6 +3880,10 @@ static struct pid *pidfd_to_pid(const struct file *file)
return tgid_pidfd_to_pid(file);
}
+#define PIDFD_SEND_SIGNAL_FLAGS \
+ (PIDFD_SIGNAL_THREAD | PIDFD_SIGNAL_THREAD_GROUP | \
+ PIDFD_SIGNAL_PROCESS_GROUP)
+
/**
* sys_pidfd_send_signal - Signal a process through a pidfd
* @pidfd: file descriptor of the process
@@ -3868,14 +3891,10 @@ static struct pid *pidfd_to_pid(const struct file *file)
* @info: signal info
* @flags: future flags
*
- * The syscall currently only signals via PIDTYPE_PID which covers
- * kill(<positive-pid>, <signal>. It does not signal threads or process
- * groups.
- * In order to extend the syscall to threads and process groups the @flags
- * argument should be used. In essence, the @flags argument will determine
- * what is signaled and not the file descriptor itself. Put in other words,
- * grouping is a property of the flags argument not a property of the file
- * descriptor.
+ * Send the signal to the thread group or to the individual thread depending
+ * on PIDFD_THREAD.
+ * In the future extension to @flags may be used to override the default scope
+ * of @pidfd.
*
* Return: 0 on success, negative errno on failure
*/
@@ -3886,9 +3905,14 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
struct fd f;
struct pid *pid;
kernel_siginfo_t kinfo;
+ enum pid_type type;
/* Enforce flags be set to 0 until we add an extension. */
- if (flags)
+ if (flags & ~PIDFD_SEND_SIGNAL_FLAGS)
+ return -EINVAL;
+
+ /* Ensure that only a single signal scope determining flag is set. */
+ if (hweight32(flags & PIDFD_SEND_SIGNAL_FLAGS) > 1)
return -EINVAL;
f = fdget(pidfd);
@@ -3906,6 +3930,25 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
if (!access_pidfd_pidns(pid))
goto err;
+ switch (flags) {
+ case 0:
+ /* Infer scope from the type of pidfd. */
+ if (f.file->f_flags & PIDFD_THREAD)
+ type = PIDTYPE_PID;
+ else
+ type = PIDTYPE_TGID;
+ break;
+ case PIDFD_SIGNAL_THREAD:
+ type = PIDTYPE_PID;
+ break;
+ case PIDFD_SIGNAL_THREAD_GROUP:
+ type = PIDTYPE_TGID;
+ break;
+ case PIDFD_SIGNAL_PROCESS_GROUP:
+ type = PIDTYPE_PGID;
+ break;
+ }
+
if (info) {
ret = copy_siginfo_from_user_any(&kinfo, info);
if (unlikely(ret))
@@ -3917,15 +3960,17 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
/* Only allow sending arbitrary signals to yourself. */
ret = -EPERM;
- if ((task_pid(current) != pid) &&
+ if ((task_pid(current) != pid || type > PIDTYPE_TGID) &&
(kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL))
goto err;
} else {
- prepare_kill_siginfo(sig, &kinfo);
+ prepare_kill_siginfo(sig, &kinfo, type);
}
- ret = kill_pid_info(sig, &kinfo, pid);
-
+ if (type == PIDTYPE_PGID)
+ ret = kill_pgrp_info(sig, &kinfo, pid);
+ else
+ ret = kill_pid_info_type(sig, &kinfo, pid, type);
err:
fdput(f);
return ret;
@@ -3965,12 +4010,7 @@ static int do_tkill(pid_t tgid, pid_t pid, int sig)
{
struct kernel_siginfo info;
- clear_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 = from_kuid_munged(current_user_ns(), current_uid());
+ prepare_kill_siginfo(sig, &info, PIDTYPE_PID);
return do_send_specific(tgid, pid, sig, &info);
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 16:15:36 +0000