Re: [PATCH v2 1/4] vfs: create a generic checking function for FS_IOC_SETFLAGS

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On Tue 11-06-19 17:42:58, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> 
> Create a generic checking function for the incoming FS_IOC_SETFLAGS flag
> values so that we can standardize the implementations that follow ext4's
> flag values.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

The patch looks good to me. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

								Honza

> ---
> v2: fix jfs locking and remove its opencoded flags check
> ---
>  fs/btrfs/ioctl.c    |   13 +++++--------
>  fs/efivarfs/file.c  |   18 +++++++++++++-----
>  fs/ext2/ioctl.c     |   16 ++++------------
>  fs/ext4/ioctl.c     |   13 +++----------
>  fs/f2fs/file.c      |    7 ++++---
>  fs/gfs2/file.c      |   42 +++++++++++++++++++++++++++++-------------
>  fs/hfsplus/ioctl.c  |   21 ++++++++++++---------
>  fs/inode.c          |   17 +++++++++++++++++
>  fs/jfs/ioctl.c      |   22 +++++++---------------
>  fs/nilfs2/ioctl.c   |    9 ++-------
>  fs/ocfs2/ioctl.c    |   13 +++----------
>  fs/reiserfs/ioctl.c |   10 ++++------
>  fs/ubifs/ioctl.c    |   13 +++----------
>  include/linux/fs.h  |    2 ++
>  14 files changed, 108 insertions(+), 108 deletions(-)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 6dafa857bbb9..f408aa93b0cf 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -187,7 +187,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
>  	struct btrfs_inode *binode = BTRFS_I(inode);
>  	struct btrfs_root *root = binode->root;
>  	struct btrfs_trans_handle *trans;
> -	unsigned int fsflags;
> +	unsigned int fsflags, old_fsflags;
>  	int ret;
>  	const char *comp = NULL;
>  	u32 binode_flags = binode->flags;
> @@ -212,13 +212,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
>  	inode_lock(inode);
>  
>  	fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
> -	if ((fsflags ^ btrfs_inode_flags_to_fsflags(binode->flags)) &
> -	    (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
> -		if (!capable(CAP_LINUX_IMMUTABLE)) {
> -			ret = -EPERM;
> -			goto out_unlock;
> -		}
> -	}
> +	old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
> +	ret = vfs_ioc_setflags_check(inode, old_fsflags, fsflags);
> +	if (ret)
> +		goto out_unlock;
>  
>  	if (fsflags & FS_SYNC_FL)
>  		binode_flags |= BTRFS_INODE_SYNC;
> diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
> index 8e568428c88b..f4f6c1bec132 100644
> --- a/fs/efivarfs/file.c
> +++ b/fs/efivarfs/file.c
> @@ -110,16 +110,22 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
>  	return size;
>  }
>  
> -static int
> -efivarfs_ioc_getxflags(struct file *file, void __user *arg)
> +static inline unsigned int efivarfs_getflags(struct inode *inode)
>  {
> -	struct inode *inode = file->f_mapping->host;
>  	unsigned int i_flags;
>  	unsigned int flags = 0;
>  
>  	i_flags = inode->i_flags;
>  	if (i_flags & S_IMMUTABLE)
>  		flags |= FS_IMMUTABLE_FL;
> +	return flags;
> +}
> +
> +static int
> +efivarfs_ioc_getxflags(struct file *file, void __user *arg)
> +{
> +	struct inode *inode = file->f_mapping->host;
> +	unsigned int flags = efivarfs_getflags(inode);
>  
>  	if (copy_to_user(arg, &flags, sizeof(flags)))
>  		return -EFAULT;
> @@ -132,6 +138,7 @@ efivarfs_ioc_setxflags(struct file *file, void __user *arg)
>  	struct inode *inode = file->f_mapping->host;
>  	unsigned int flags;
>  	unsigned int i_flags = 0;
> +	unsigned int oldflags = efivarfs_getflags(inode);
>  	int error;
>  
>  	if (!inode_owner_or_capable(inode))
> @@ -143,8 +150,9 @@ efivarfs_ioc_setxflags(struct file *file, void __user *arg)
>  	if (flags & ~FS_IMMUTABLE_FL)
>  		return -EOPNOTSUPP;
>  
> -	if (!capable(CAP_LINUX_IMMUTABLE))
> -		return -EPERM;
> +	error = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (error)
> +		return error;
>  
>  	if (flags & FS_IMMUTABLE_FL)
>  		i_flags |= S_IMMUTABLE;
> diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
> index 0367c0039e68..88b3b9720023 100644
> --- a/fs/ext2/ioctl.c
> +++ b/fs/ext2/ioctl.c
> @@ -60,18 +60,10 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  		}
>  		oldflags = ei->i_flags;
>  
> -		/*
> -		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> -		 * the relevant capability.
> -		 *
> -		 * This test looks nicer. Thanks to Pauline Middelink
> -		 */
> -		if ((flags ^ oldflags) & (EXT2_APPEND_FL | EXT2_IMMUTABLE_FL)) {
> -			if (!capable(CAP_LINUX_IMMUTABLE)) {
> -				inode_unlock(inode);
> -				ret = -EPERM;
> -				goto setflags_out;
> -			}
> +		ret = vfs_ioc_setflags_check(inode, oldflags, flags);
> +		if (ret) {
> +			inode_unlock(inode);
> +			goto setflags_out;
>  		}
>  
>  		flags = flags & EXT2_FL_USER_MODIFIABLE;
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index e486e49b31ed..5126ee351a84 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -289,16 +289,9 @@ static int ext4_ioctl_setflags(struct inode *inode,
>  	/* The JOURNAL_DATA flag is modifiable only by root */
>  	jflag = flags & EXT4_JOURNAL_DATA_FL;
>  
> -	/*
> -	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> -	 * the relevant capability.
> -	 *
> -	 * This test looks nicer. Thanks to Pauline Middelink
> -	 */
> -	if ((flags ^ oldflags) & (EXT4_APPEND_FL | EXT4_IMMUTABLE_FL)) {
> -		if (!capable(CAP_LINUX_IMMUTABLE))
> -			goto flags_out;
> -	}
> +	err = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (err)
> +		goto flags_out;
>  
>  	/*
>  	 * The JOURNAL_DATA flag can only be changed by
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 45b45f37d347..a969d5497e03 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1670,6 +1670,7 @@ static int __f2fs_ioc_setflags(struct inode *inode, unsigned int flags)
>  {
>  	struct f2fs_inode_info *fi = F2FS_I(inode);
>  	unsigned int oldflags;
> +	int err;
>  
>  	/* Is it quota file? Do not allow user to mess with it */
>  	if (IS_NOQUOTA(inode))
> @@ -1679,9 +1680,9 @@ static int __f2fs_ioc_setflags(struct inode *inode, unsigned int flags)
>  
>  	oldflags = fi->i_flags;
>  
> -	if ((flags ^ oldflags) & (F2FS_APPEND_FL | F2FS_IMMUTABLE_FL))
> -		if (!capable(CAP_LINUX_IMMUTABLE))
> -			return -EPERM;
> +	err = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (err)
> +		return err;
>  
>  	flags = flags & F2FS_FL_USER_MODIFIABLE;
>  	flags |= oldflags & ~F2FS_FL_USER_MODIFIABLE;
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index d174b1f8fd08..99f53cf699c6 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -136,27 +136,36 @@ static struct {
>  	{FS_JOURNAL_DATA_FL, GFS2_DIF_JDATA | GFS2_DIF_INHERIT_JDATA},
>  };
>  
> +static inline u32 gfs2_gfsflags_to_fsflags(struct inode *inode, u32 gfsflags)
> +{
> +	int i;
> +	u32 fsflags = 0;
> +
> +	if (S_ISDIR(inode->i_mode))
> +		gfsflags &= ~GFS2_DIF_JDATA;
> +	else
> +		gfsflags &= ~GFS2_DIF_INHERIT_JDATA;
> +
> +	for (i = 0; i < ARRAY_SIZE(fsflag_gfs2flag); i++)
> +		if (gfsflags & fsflag_gfs2flag[i].gfsflag)
> +			fsflags |= fsflag_gfs2flag[i].fsflag;
> +	return fsflags;
> +}
> +
>  static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
>  {
>  	struct inode *inode = file_inode(filp);
>  	struct gfs2_inode *ip = GFS2_I(inode);
>  	struct gfs2_holder gh;
> -	int i, error;
> -	u32 gfsflags, fsflags = 0;
> +	int error;
> +	u32 fsflags;
>  
>  	gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
>  	error = gfs2_glock_nq(&gh);
>  	if (error)
>  		goto out_uninit;
>  
> -	gfsflags = ip->i_diskflags;
> -	if (S_ISDIR(inode->i_mode))
> -		gfsflags &= ~GFS2_DIF_JDATA;
> -	else
> -		gfsflags &= ~GFS2_DIF_INHERIT_JDATA;
> -	for (i = 0; i < ARRAY_SIZE(fsflag_gfs2flag); i++)
> -		if (gfsflags & fsflag_gfs2flag[i].gfsflag)
> -			fsflags |= fsflag_gfs2flag[i].fsflag;
> +	fsflags = gfs2_gfsflags_to_fsflags(inode, ip->i_diskflags);
>  
>  	if (put_user(fsflags, ptr))
>  		error = -EFAULT;
> @@ -200,9 +209,11 @@ void gfs2_set_inode_flags(struct inode *inode)
>   * @filp: file pointer
>   * @reqflags: The flags to set
>   * @mask: Indicates which flags are valid
> + * @fsflags: The FS_* inode flags passed in
>   *
>   */
> -static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
> +static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask,
> +			     const u32 fsflags)
>  {
>  	struct inode *inode = file_inode(filp);
>  	struct gfs2_inode *ip = GFS2_I(inode);
> @@ -210,7 +221,7 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
>  	struct buffer_head *bh;
>  	struct gfs2_holder gh;
>  	int error;
> -	u32 new_flags, flags;
> +	u32 new_flags, flags, oldflags;
>  
>  	error = mnt_want_write_file(filp);
>  	if (error)
> @@ -220,6 +231,11 @@ static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
>  	if (error)
>  		goto out_drop_write;
>  
> +	oldflags = gfs2_gfsflags_to_fsflags(inode, ip->i_diskflags);
> +	error = vfs_ioc_setflags_check(inode, oldflags, fsflags);
> +	if (error)
> +		goto out;
> +
>  	error = -EACCES;
>  	if (!inode_owner_or_capable(inode))
>  		goto out;
> @@ -308,7 +324,7 @@ static int gfs2_set_flags(struct file *filp, u32 __user *ptr)
>  		mask &= ~(GFS2_DIF_TOPDIR | GFS2_DIF_INHERIT_JDATA);
>  	}
>  
> -	return do_gfs2_set_flags(filp, gfsflags, mask);
> +	return do_gfs2_set_flags(filp, gfsflags, mask, fsflags);
>  }
>  
>  static int gfs2_getlabel(struct file *filp, char __user *label)
> diff --git a/fs/hfsplus/ioctl.c b/fs/hfsplus/ioctl.c
> index 5e6502ef7415..862a3c9481d7 100644
> --- a/fs/hfsplus/ioctl.c
> +++ b/fs/hfsplus/ioctl.c
> @@ -57,9 +57,8 @@ static int hfsplus_ioctl_bless(struct file *file, int __user *user_flags)
>  	return 0;
>  }
>  
> -static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
> +static inline unsigned int hfsplus_getflags(struct inode *inode)
>  {
> -	struct inode *inode = file_inode(file);
>  	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
>  	unsigned int flags = 0;
>  
> @@ -69,6 +68,13 @@ static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
>  		flags |= FS_APPEND_FL;
>  	if (hip->userflags & HFSPLUS_FLG_NODUMP)
>  		flags |= FS_NODUMP_FL;
> +	return flags;
> +}
> +
> +static int hfsplus_ioctl_getflags(struct file *file, int __user *user_flags)
> +{
> +	struct inode *inode = file_inode(file);
> +	unsigned int flags = hfsplus_getflags(inode);
>  
>  	return put_user(flags, user_flags);
>  }
> @@ -78,6 +84,7 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
>  	struct inode *inode = file_inode(file);
>  	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
>  	unsigned int flags, new_fl = 0;
> +	unsigned int oldflags = hfsplus_getflags(inode);
>  	int err = 0;
>  
>  	err = mnt_want_write_file(file);
> @@ -96,13 +103,9 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
>  
>  	inode_lock(inode);
>  
> -	if ((flags & (FS_IMMUTABLE_FL|FS_APPEND_FL)) ||
> -	    inode->i_flags & (S_IMMUTABLE|S_APPEND)) {
> -		if (!capable(CAP_LINUX_IMMUTABLE)) {
> -			err = -EPERM;
> -			goto out_unlock_inode;
> -		}
> -	}
> +	err = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (err)
> +		goto out_unlock_inode;
>  
>  	/* don't silently ignore unsupported ext2 flags */
>  	if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
> diff --git a/fs/inode.c b/fs/inode.c
> index df6542ec3b88..0ce60b720608 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2170,3 +2170,20 @@ struct timespec64 current_time(struct inode *inode)
>  	return timespec64_trunc(now, inode->i_sb->s_time_gran);
>  }
>  EXPORT_SYMBOL(current_time);
> +
> +/* Generic function to check FS_IOC_SETFLAGS values. */
> +int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags)
> +{
> +	/*
> +	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> +	 * the relevant capability.
> +	 *
> +	 * This test looks nicer. Thanks to Pauline Middelink
> +	 */
> +	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL) &&
> +	    !capable(CAP_LINUX_IMMUTABLE))
> +		return -EPERM;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(vfs_ioc_setflags_check);
> diff --git a/fs/jfs/ioctl.c b/fs/jfs/ioctl.c
> index ba34dae8bd9f..b485c2d7620f 100644
> --- a/fs/jfs/ioctl.c
> +++ b/fs/jfs/ioctl.c
> @@ -98,24 +98,16 @@ long jfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  		/* Lock against other parallel changes of flags */
>  		inode_lock(inode);
>  
> -		oldflags = jfs_inode->mode2;
> -
> -		/*
> -		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> -		 * the relevant capability.
> -		 */
> -		if ((oldflags & JFS_IMMUTABLE_FL) ||
> -			((flags ^ oldflags) &
> -			(JFS_APPEND_FL | JFS_IMMUTABLE_FL))) {
> -			if (!capable(CAP_LINUX_IMMUTABLE)) {
> -				inode_unlock(inode);
> -				err = -EPERM;
> -				goto setflags_out;
> -			}
> +		oldflags = jfs_map_ext2(jfs_inode->mode2 & JFS_FL_USER_VISIBLE,
> +					0);
> +		err = vfs_ioc_setflags_check(inode, oldflags, flags);
> +		if (err) {
> +			inode_unlock(inode);
> +			goto setflags_out;
>  		}
>  
>  		flags = flags & JFS_FL_USER_MODIFIABLE;
> -		flags |= oldflags & ~JFS_FL_USER_MODIFIABLE;
> +		flags |= jfs_inode->mode2 & ~JFS_FL_USER_MODIFIABLE;
>  		jfs_inode->mode2 = flags;
>  
>  		jfs_set_inode_flags(inode);
> diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
> index 9b96d79eea6c..0632336d2515 100644
> --- a/fs/nilfs2/ioctl.c
> +++ b/fs/nilfs2/ioctl.c
> @@ -148,13 +148,8 @@ static int nilfs_ioctl_setflags(struct inode *inode, struct file *filp,
>  
>  	oldflags = NILFS_I(inode)->i_flags;
>  
> -	/*
> -	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by the
> -	 * relevant capability.
> -	 */
> -	ret = -EPERM;
> -	if (((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) &&
> -	    !capable(CAP_LINUX_IMMUTABLE))
> +	ret = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (ret)
>  		goto out;
>  
>  	ret = nilfs_transaction_begin(inode->i_sb, &ti, 0);
> diff --git a/fs/ocfs2/ioctl.c b/fs/ocfs2/ioctl.c
> index 994726ada857..467a2faf0305 100644
> --- a/fs/ocfs2/ioctl.c
> +++ b/fs/ocfs2/ioctl.c
> @@ -106,16 +106,9 @@ static int ocfs2_set_inode_attr(struct inode *inode, unsigned flags,
>  	flags = flags & mask;
>  	flags |= oldflags & ~mask;
>  
> -	/*
> -	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> -	 * the relevant capability.
> -	 */
> -	status = -EPERM;
> -	if ((oldflags & OCFS2_IMMUTABLE_FL) || ((flags ^ oldflags) &
> -		(OCFS2_APPEND_FL | OCFS2_IMMUTABLE_FL))) {
> -		if (!capable(CAP_LINUX_IMMUTABLE))
> -			goto bail_unlock;
> -	}
> +	status = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (status)
> +		goto bail_unlock;
>  
>  	handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
>  	if (IS_ERR(handle)) {
> diff --git a/fs/reiserfs/ioctl.c b/fs/reiserfs/ioctl.c
> index acbbaf7a0bb2..92bcb1ecd994 100644
> --- a/fs/reiserfs/ioctl.c
> +++ b/fs/reiserfs/ioctl.c
> @@ -74,13 +74,11 @@ long reiserfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  				err = -EPERM;
>  				goto setflags_out;
>  			}
> -			if (((flags ^ REISERFS_I(inode)->
> -			      i_attrs) & (REISERFS_IMMUTABLE_FL |
> -					  REISERFS_APPEND_FL))
> -			    && !capable(CAP_LINUX_IMMUTABLE)) {
> -				err = -EPERM;
> +			err = vfs_ioc_setflags_check(inode,
> +						     REISERFS_I(inode)->i_attrs,
> +						     flags);
> +			if (err)
>  				goto setflags_out;
> -			}
>  			if ((flags & REISERFS_NOTAIL_FL) &&
>  			    S_ISREG(inode->i_mode)) {
>  				int result;
> diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
> index 4f1a397fda69..bdea836fc38b 100644
> --- a/fs/ubifs/ioctl.c
> +++ b/fs/ubifs/ioctl.c
> @@ -107,18 +107,11 @@ static int setflags(struct inode *inode, int flags)
>  	if (err)
>  		return err;
>  
> -	/*
> -	 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
> -	 * the relevant capability.
> -	 */
>  	mutex_lock(&ui->ui_mutex);
>  	oldflags = ubifs2ioctl(ui->flags);
> -	if ((flags ^ oldflags) & (FS_APPEND_FL | FS_IMMUTABLE_FL)) {
> -		if (!capable(CAP_LINUX_IMMUTABLE)) {
> -			err = -EPERM;
> -			goto out_unlock;
> -		}
> -	}
> +	err = vfs_ioc_setflags_check(inode, oldflags, flags);
> +	if (err)
> +		goto out_unlock;
>  
>  	ui->flags = ioctl2ubifs(flags);
>  	ubifs_set_inode_flags(inode);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index f7fdfe93e25d..1825d055808c 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -3546,4 +3546,6 @@ static inline struct sock *io_uring_get_socket(struct file *file)
>  }
>  #endif
>  
> +int vfs_ioc_setflags_check(struct inode *inode, int oldflags, int flags);
> +
>  #endif /* _LINUX_FS_H */
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR



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