Commit 4bd6a735 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Al Viro
Browse files

sysctl: Convert to iter interfaces 



Using the read_iter/write_iter interfaces allows for in-kernel users
to set sysctls without using set_fs().  Also, the buffer is a string,
so give it the real type of 'char *', not void *.

[AV: Christoph's fixup folded in]

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent fd5a13f4

fs/proc/proc_sysctl.c

+24 −24
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/cred.h>

#include <linux/namei.h>

#include <linux/mm.h>

#include <linux/uio.h>

#include <linux/module.h>

#include <linux/bpf-cgroup.h>

#include <linux/mount.h>
@@ -540,13 +541,14 @@ out: 
	return err;

}



static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf,

		size_t count, loff_t *ppos, int write)

static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter,

		int write)

{

	struct inode *inode = file_inode(filp);

	struct inode *inode = file_inode(iocb->ki_filp);

	struct ctl_table_header *head = grab_header(inode);

	struct ctl_table *table = PROC_I(inode)->sysctl_entry;

	void *kbuf;

	size_t count = iov_iter_count(iter);

	char *kbuf;

	ssize_t error;



	if (IS_ERR(head))
@@ -569,32 +571,30 @@ static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf, 
	error = -ENOMEM;

	if (count >= KMALLOC_MAX_SIZE)

		goto out;



	if (write) {

		kbuf = memdup_user_nul(ubuf, count);

		if (IS_ERR(kbuf)) {

			error = PTR_ERR(kbuf);

			goto out;

		}

	} else {

		kbuf = kzalloc(count, GFP_KERNEL);

	kbuf = kzalloc(count + 1, GFP_KERNEL);

	if (!kbuf)

		goto out;



	if (write) {

		error = -EFAULT;

		if (!copy_from_iter_full(kbuf, count, iter))

			goto out_free_buf;

		kbuf[count] = '\0';

	}



	error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count,

					   ppos);

					   &iocb->ki_pos);

	if (error)

		goto out_free_buf;



	/* careful: calling conventions are nasty here */

	error = table->proc_handler(table, write, kbuf, &count, ppos);

	error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos);

	if (error)

		goto out_free_buf;



	if (!write) {

		error = -EFAULT;

		if (copy_to_user(ubuf, kbuf, count))

		if (copy_to_iter(kbuf, count, iter) < count)

			goto out_free_buf;

	}
@@ -607,16 +607,14 @@ out: 
	return error;

}



static ssize_t proc_sys_read(struct file *filp, char __user *buf,

				size_t count, loff_t *ppos)

static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter)

{

	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);

	return proc_sys_call_handler(iocb, iter, 0);

}



static ssize_t proc_sys_write(struct file *filp, const char __user *buf,

				size_t count, loff_t *ppos)

static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter)

{

	return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);

	return proc_sys_call_handler(iocb, iter, 1);

}



static int proc_sys_open(struct inode *inode, struct file *filp)
@@ -853,8 +851,10 @@ static int proc_sys_getattr(const struct path *path, struct kstat *stat, 
static const struct file_operations proc_sys_file_operations = {

	.open		= proc_sys_open,

	.poll		= proc_sys_poll,

	.read		= proc_sys_read,

	.write		= proc_sys_write,

	.read_iter	= proc_sys_read,

	.write_iter	= proc_sys_write,

	.splice_read	= generic_file_splice_read,

	.splice_write	= iter_file_splice_write,

	.llseek		= default_llseek,

};

include/linux/bpf-cgroup.h

+1 −1
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, 


int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,

				   struct ctl_table *table, int write,

				   void **buf, size_t *pcount, loff_t *ppos,

				   char **buf, size_t *pcount, loff_t *ppos,

				   enum bpf_attach_type type);



int __cgroup_bpf_run_filter_setsockopt(struct sock *sock, int *level,

kernel/bpf/cgroup.c

+1 −1
Original line number Diff line number Diff line
@@ -1226,7 +1226,7 @@ const struct bpf_verifier_ops cg_dev_verifier_ops = { 
 */

int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head,

				   struct ctl_table *table, int write,

				   void **buf, size_t *pcount, loff_t *ppos,

				   char **buf, size_t *pcount, loff_t *ppos,

				   enum bpf_attach_type type)

{

	struct bpf_sysctl_kern ctx = {

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