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f2fs: support FS_IOC_{GET,SET}FSLABEL

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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: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Chao Yu 2019-07-17 17:06:11 +08:00 committed by Jaegeuk Kim
parent 899fee36fa
commit 4507847c86
2 changed files with 72 additions and 0 deletions
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3
fs/f2fs/f2fs.h
View File

@ -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

69
fs/f2fs/file.c
View File

@ -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;