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authorChristian Brauner <[email protected]>2019-04-17 22:50:25 +0200
committerChristian Brauner <[email protected]>2019-05-07 14:31:03 +0200
commit2151ad1b067275730de1b38c7257478cae47d29e (patch)
tree45276131c61540bef60a8b9e6fde6b8b95401b54
parentb3e5838252665ee4cfa76b82bdf1198dca81e5be (diff)
signal: support CLONE_PIDFD with pidfd_send_signal
Let pidfd_send_signal() use pidfds retrieved via CLONE_PIDFD. With this patch pidfd_send_signal() becomes independent of procfs. This fullfils the request made when we merged the pidfd_send_signal() patchset. The pidfd_send_signal() syscall is now always available allowing for it to be used by users without procfs mounted or even users without procfs support compiled into the kernel. Signed-off-by: Christian Brauner <[email protected]> Co-developed-by: Jann Horn <[email protected]> Signed-off-by: Jann Horn <[email protected]> Acked-by: Oleg Nesterov <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: "Eric W. Biederman" <[email protected]> Cc: Kees Cook <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: David Howells <[email protected]> Cc: "Michael Kerrisk (man-pages)" <[email protected]> Cc: Andy Lutomirsky <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Aleksa Sarai <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Al Viro <[email protected]>
-rw-r--r--kernel/signal.c12
-rw-r--r--kernel/sys_ni.c3
2 files changed, 9 insertions, 6 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index f98448cf2def..1581140f2d99 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3513,7 +3513,6 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
return kill_something_info(sig, &info, pid);
}
-#ifdef CONFIG_PROC_FS
/*
* Verify that the signaler and signalee either are in the same pid namespace
* or that the signaler's pid namespace is an ancestor of the signalee's pid
@@ -3550,6 +3549,14 @@ static int copy_siginfo_from_user_any(kernel_siginfo_t *kinfo, siginfo_t *info)
return copy_siginfo_from_user(kinfo, info);
}
+static struct pid *pidfd_to_pid(const struct file *file)
+{
+ if (file->f_op == &pidfd_fops)
+ return file->private_data;
+
+ return tgid_pidfd_to_pid(file);
+}
+
/**
* sys_pidfd_send_signal - send a signal to a process through a task file
* descriptor
@@ -3586,7 +3593,7 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
return -EBADF;
/* Is this a pidfd? */
- pid = tgid_pidfd_to_pid(f.file);
+ pid = pidfd_to_pid(f.file);
if (IS_ERR(pid)) {
ret = PTR_ERR(pid);
goto err;
@@ -3620,7 +3627,6 @@ err:
fdput(f);
return ret;
}
-#endif /* CONFIG_PROC_FS */
static int
do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index d21f4befaea4..4d9ae5ea6caf 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -167,9 +167,6 @@ COND_SYSCALL(syslog);
/* kernel/sched/core.c */
-/* kernel/signal.c */
-COND_SYSCALL(pidfd_send_signal);
-
/* kernel/sys.c */
COND_SYSCALL(setregid);
COND_SYSCALL(setgid);