From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Brauner Subject: [PATCH v3 3/4] signal: support CLONE_PIDFD with pidfd_send_signal Date: Fri, 19 Apr 2019 14:09:03 +0200 Message-ID: <20190419120904.27502-4-christian@brauner.io> References: <20190419120904.27502-1-christian@brauner.io> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190419120904.27502-1-christian@brauner.io> Sender: linux-kernel-owner@vger.kernel.org To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, jannh@google.com, dhowells@redhat.com, oleg@redhat.com, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Cc: serge@hallyn.com, luto@kernel.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, tglx@linutronix.de, mtk.manpages@gmail.com, akpm@linux-foundation.org, cyphar@cyphar.com, joel@joelfernandes.org, dancol@google.com, Christian Brauner , Jann Horn List-Id: linux-api@vger.kernel.org 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 Co-developed-by: Jann Horn Signed-off-by: Jann Horn Acked-by: Oleg Nesterov Cc: Arnd Bergmann Cc: "Eric W. Biederman" Cc: Kees Cook Cc: Thomas Gleixner Cc: David Howells Cc: "Michael Kerrisk (man-pages)" Cc: Andy Lutomirsky Cc: Andrew Morton Cc: Aleksa Sarai Cc: Linus Torvalds Cc: Al Viro --- /* changelog */ v1: patch unchanged v2: - Oleg Nesterov : - split s/fdget_raw()/fdget()/ into separate patch as it has nothing to do with supporting CLONE_PIDFD v3: - Christian Brauner : - Linus has applied the s/fdget_raw()/fdget()/ patch right away so the patch is gone from the series --- kernel/signal.c | 12 +++++++++--- kernel/sys_ni.c | 3 --- 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 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, 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); -- 2.21.0