signal: support CLONE_PIDFD with pidfd_send_signal (2151ad1b) · Commits · 戴 / test

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 <christian@brauner.io> Co-developed-by:

Jann Horn <jannh@google.com> Signed-off-by:

Jann Horn <jannh@google.com> Acked-by:

Oleg Nesterov <oleg@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Howells <dhowells@redhat.com> Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk>

kernel/signal.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -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)

kernel/sys_ni.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -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);

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