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Commit 796f571b authored by Lafcadio Wluiki's avatar Lafcadio Wluiki Committed by Linus Torvalds
Browse files

procfs: use an enum for possible hidepid values 

Previously, the hidepid parameter was checked by comparing literal
integers 0, 1, 2.  Let's add a proper enum for this, to make the
checking more expressive:

        0 → HIDEPID_OFF
        1 → HIDEPID_NO_ACCESS
        2 → HIDEPID_INVISIBLE

This changes the internal labelling only, the userspace-facing interface
remains unmodified, and still works with literal integers 0, 1, 2.

No functional changes.

Link: http://lkml.kernel.org/r/1484572984-13388-2-git-send-email-djalal@gmail.com


Signed-off-by: default avatarLafcadio Wluiki <wluikil@gmail.com>
Signed-off-by: default avatarDjalal Harouni <tixxdz@gmail.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a0a07b87

fs/proc/base.c

+4 −4
Original line number Diff line number Diff line
@@ -697,11 +697,11 @@ static int proc_pid_permission(struct inode *inode, int mask) 
	task = get_proc_task(inode);

	if (!task)

		return -ESRCH;

	has_perms = has_pid_permissions(pid, task, 1);

	has_perms = has_pid_permissions(pid, task, HIDEPID_NO_ACCESS);

	put_task_struct(task);



	if (!has_perms) {

		if (pid->hide_pid == 2) {

		if (pid->hide_pid == HIDEPID_INVISIBLE) {

			/*

			 * Let's make getdents(), stat(), and open()

			 * consistent with each other.  If a process
@@ -1737,7 +1737,7 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) 
	stat->gid = GLOBAL_ROOT_GID;

	task = pid_task(proc_pid(inode), PIDTYPE_PID);

	if (task) {

		if (!has_pid_permissions(pid, task, 2)) {

		if (!has_pid_permissions(pid, task, HIDEPID_INVISIBLE)) {

			rcu_read_unlock();

			/*

			 * This doesn't prevent learning whether PID exists,
@@ -3168,7 +3168,7 @@ int proc_pid_readdir(struct file *file, struct dir_context *ctx) 
		int len;



		cond_resched();

		if (!has_pid_permissions(ns, iter.task, 2))

		if (!has_pid_permissions(ns, iter.task, HIDEPID_INVISIBLE))

			continue;



		len = snprintf(name, sizeof(name), "%d", iter.tgid);

fs/proc/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -107,7 +107,7 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root) 


	if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))

		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));

	if (pid->hide_pid != 0)

	if (pid->hide_pid != HIDEPID_OFF)

		seq_printf(seq, ",hidepid=%u", pid->hide_pid);



	return 0;

fs/proc/root.c

+2 −1
Original line number Diff line number Diff line
@@ -58,7 +58,8 @@ int proc_parse_options(char *options, struct pid_namespace *pid) 
		case Opt_hidepid:

			if (match_int(&args[0], &option))

				return 0;

			if (option < 0 || option > 2) {

			if (option < HIDEPID_OFF ||

			    option > HIDEPID_INVISIBLE) {

				pr_err("proc: hidepid value must be between 0 and 2.\n");

				return 0;

			}

include/linux/pid_namespace.h

+6 −0
Original line number Diff line number Diff line
@@ -21,6 +21,12 @@ struct pidmap { 


struct fs_pin;



enum { /* definitions for pid_namespace's hide_pid field */

	HIDEPID_OFF	  = 0,

	HIDEPID_NO_ACCESS = 1,

	HIDEPID_INVISIBLE = 2,

};



struct pid_namespace {

	struct kref kref;

	struct pidmap pidmap[PIDMAP_ENTRIES];