Commit 4507847c authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: support FS_IOC_{GET,SET}FSLABEL 



Support two generic fs ioctls FS_IOC_{GET,SET}FSLABEL, letting
f2fs pass generic/492 testcase.

Fixes were made by Eric where:
 - f2fs: fix buffer overruns in FS_IOC_{GET, SET}FSLABEL
   utf16s_to_utf8s() and utf8s_to_utf16s() take the number of characters,
   not the number of bytes.

 - f2fs: fix copying too many bytes in FS_IOC_SETFSLABEL
   Userspace provides a null-terminated string, so don't assume that the
   full FSLABEL_MAX bytes can always be copied.

 - f2fs: add missing authorization check in FS_IOC_SETFSLABEL
   FS_IOC_SETFSLABEL modifies the filesystem superblock, so it shouldn't be
   allowed to regular users.  Require CAP_SYS_ADMIN, like xfs and btrfs do.

Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 899fee36

fs/f2fs/f2fs.h

+3 −0
Original line number Diff line number Diff line
@@ -418,6 +418,9 @@ static inline bool __has_cursum_space(struct f2fs_journal *journal, 
#define F2FS_IOC_PRECACHE_EXTENTS	_IO(F2FS_IOCTL_MAGIC, 15)

#define F2FS_IOC_RESIZE_FS		_IOW(F2FS_IOCTL_MAGIC, 16, __u64)



#define F2FS_IOC_GET_VOLUME_NAME	FS_IOC_GETFSLABEL

#define F2FS_IOC_SET_VOLUME_NAME	FS_IOC_SETFSLABEL



#define F2FS_IOC_SET_ENCRYPTION_POLICY	FS_IOC_SET_ENCRYPTION_POLICY

#define F2FS_IOC_GET_ENCRYPTION_POLICY	FS_IOC_GET_ENCRYPTION_POLICY

#define F2FS_IOC_GET_ENCRYPTION_PWSALT	FS_IOC_GET_ENCRYPTION_PWSALT

fs/f2fs/file.c

+69 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
#include <linux/uio.h>

#include <linux/uuid.h>

#include <linux/file.h>

#include <linux/nls.h>



#include "f2fs.h"

#include "node.h"
@@ -3081,6 +3082,68 @@ static int f2fs_ioc_resize_fs(struct file *filp, unsigned long arg) 
	return ret;

}



static int f2fs_get_volume_name(struct file *filp, unsigned long arg)

{

	struct inode *inode = file_inode(filp);

	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

	char *vbuf;

	int count;

	int err = 0;



	vbuf = f2fs_kzalloc(sbi, MAX_VOLUME_NAME, GFP_KERNEL);

	if (!vbuf)

		return -ENOMEM;



	down_read(&sbi->sb_lock);

	count = utf16s_to_utf8s(sbi->raw_super->volume_name,

			ARRAY_SIZE(sbi->raw_super->volume_name),

			UTF16_LITTLE_ENDIAN, vbuf, MAX_VOLUME_NAME);

	up_read(&sbi->sb_lock);



	if (copy_to_user((char __user *)arg, vbuf,

				min(FSLABEL_MAX, count)))

		err = -EFAULT;



	kvfree(vbuf);

	return err;

}



static int f2fs_set_volume_name(struct file *filp, unsigned long arg)

{

	struct inode *inode = file_inode(filp);

	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);

	char *vbuf;

	int err = 0;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	vbuf = strndup_user((const char __user *)arg, FSLABEL_MAX);

	if (IS_ERR(vbuf))

		return PTR_ERR(vbuf);



	err = mnt_want_write_file(filp);

	if (err)

		goto out;



	down_write(&sbi->sb_lock);



	memset(sbi->raw_super->volume_name, 0,

			sizeof(sbi->raw_super->volume_name));

	utf8s_to_utf16s(vbuf, strlen(vbuf), UTF16_LITTLE_ENDIAN,

			sbi->raw_super->volume_name,

			ARRAY_SIZE(sbi->raw_super->volume_name));



	err = f2fs_commit_super(sbi, false);



	up_write(&sbi->sb_lock);



	mnt_drop_write_file(filp);

out:

	kfree(vbuf);

	return err;

}



long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

{

	int ret;
@@ -3144,6 +3207,10 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
		return f2fs_ioc_precache_extents(filp, arg);

	case F2FS_IOC_RESIZE_FS:

		return f2fs_ioc_resize_fs(filp, arg);

	case F2FS_IOC_GET_VOLUME_NAME:

		return f2fs_get_volume_name(filp, arg);

	case F2FS_IOC_SET_VOLUME_NAME:

		return f2fs_set_volume_name(filp, arg);

	default:

		return -ENOTTY;

	}
@@ -3253,6 +3320,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	case F2FS_IOC_SET_PIN_FILE:

	case F2FS_IOC_PRECACHE_EXTENTS:

	case F2FS_IOC_RESIZE_FS:

	case F2FS_IOC_GET_VOLUME_NAME:

	case F2FS_IOC_SET_VOLUME_NAME:

		break;

	default:

		return -ENOIOCTLCMD;

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