sysctl: move cad_pid into kernel/pid.c

Move cad_pid as well as supporting function proc_do_cad_pid into
kernel/pic.c. Replaced call to __do_proc_dointvec with proc_dointvec
inside proc_do_cad_pid which requires the copy of the ctl_table to
handle the temp value.

This is part of a greater effort to move ctl tables into their
respective subsystems which will reduce the merge conflicts in
kernel/sysctl.c.

Reviewed-by: Luis Chamberlain <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

Author: Joelgranados

kernel/pid.c

@@ -713,6 +713,29 @@ static struct ctl_table_root pid_table_root = {
 	.set_ownership	= pid_table_root_set_ownership,
 };
 
+static int proc_do_cad_pid(const struct ctl_table *table, int write, void *buffer,
+		size_t *lenp, loff_t *ppos)
+{
+	struct pid *new_pid;
+	pid_t tmp_pid;
+	int r;
+	struct ctl_table tmp_table = *table;
+
+	tmp_pid = pid_vnr(cad_pid);
+	tmp_table.data = &tmp_pid;
+
+	r = proc_dointvec(&tmp_table, write, buffer, lenp, ppos);
+	if (r || !write)
+		return r;
+
+	new_pid = find_get_pid(tmp_pid);
+	if (!new_pid)
+		return -ESRCH;
+
+	put_pid(xchg(&cad_pid, new_pid));
+	return 0;
+}
+
 static const struct ctl_table pid_table[] = {
 	{
 		.procname	= "pid_max",
@@ -723,6 +746,14 @@ static const struct ctl_table pid_table[] = {
 		.extra1		= &pid_max_min,
 		.extra2		= &pid_max_max,
 	},
+#ifdef CONFIG_PROC_SYSCTL
+	{
+		.procname	= "cad_pid",
+		.maxlen		= sizeof(int),
+		.mode		= 0600,
+		.proc_handler	= proc_do_cad_pid,
+	},
+#endif
 };
 #endif
 

kernel/sysctl.c

@@ -1224,28 +1224,6 @@ int proc_dointvec_ms_jiffies(const struct ctl_table *table, int write, void *buf
 				do_proc_dointvec_ms_jiffies_conv, NULL);
 }
 
-static int proc_do_cad_pid(const struct ctl_table *table, int write, void *buffer,
-		size_t *lenp, loff_t *ppos)
-{
-	struct pid *new_pid;
-	pid_t tmp;
-	int r;
-
-	tmp = pid_vnr(cad_pid);
-
-	r = __do_proc_dointvec(&tmp, table, write, buffer,
-			       lenp, ppos, NULL, NULL);
-	if (r || !write)
-		return r;
-
-	new_pid = find_get_pid(tmp);
-	if (!new_pid)
-		return -ESRCH;
-
-	put_pid(xchg(&cad_pid, new_pid));
-	return 0;
-}
-
 /**
  * proc_do_large_bitmap - read/write from/to a large bitmap
  * @table: the sysctl table
@@ -1541,15 +1519,6 @@ static const struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dostring,
 	},
-#endif
-#ifdef CONFIG_PROC_SYSCTL
-	{
-		.procname	= "cad_pid",
-		.data		= NULL,
-		.maxlen		= sizeof (int),
-		.mode		= 0600,
-		.proc_handler	= proc_do_cad_pid,
-	},
 #endif
 	{
 		.procname	= "overflowuid",