Commit be4df0ce authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: use generic vfs_ioc_setflags_prepare() helper 



Canonalize to ioctl FS_* flags instead of inode S_* flags.

Note that we do not call the helper vfs_ioc_fssetxattr_check()
for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem
will perform all the checks. We only need to perform the capability
check before overriding credentials.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarXiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 61536bed

fs/overlayfs/file.c

+30 −32
Original line number Diff line number Diff line
@@ -559,12 +559,28 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd, 
	return ret;

}



static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)

{

	unsigned int flags = 0;



	if (iflags & S_SYNC)

		flags |= FS_SYNC_FL;

	if (iflags & S_APPEND)

		flags |= FS_APPEND_FL;

	if (iflags & S_IMMUTABLE)

		flags |= FS_IMMUTABLE_FL;

	if (iflags & S_NOATIME)

		flags |= FS_NOATIME_FL;



	return flags;

}



static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,

				unsigned long arg, unsigned int iflags)

				unsigned long arg, unsigned int flags)

{

	long ret;

	struct inode *inode = file_inode(file);

	unsigned int old_iflags;

	unsigned int oldflags;



	if (!inode_owner_or_capable(inode))

		return -EACCES;
@@ -576,10 +592,9 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd, 
	inode_lock(inode);



	/* Check the capability before cred override */

	ret = -EPERM;

	old_iflags = READ_ONCE(inode->i_flags);

	if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&

	    !capable(CAP_LINUX_IMMUTABLE))

	oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));

	ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);

	if (ret)

		goto unlock;



	ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@@ -598,22 +613,6 @@ unlock: 


}



static unsigned int ovl_fsflags_to_iflags(unsigned int flags)

{

	unsigned int iflags = 0;



	if (flags & FS_SYNC_FL)

		iflags |= S_SYNC;

	if (flags & FS_APPEND_FL)

		iflags |= S_APPEND;

	if (flags & FS_IMMUTABLE_FL)

		iflags |= S_IMMUTABLE;

	if (flags & FS_NOATIME_FL)

		iflags |= S_NOATIME;



	return iflags;

}



static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,

				  unsigned long arg)

{
@@ -622,24 +621,23 @@ static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd, 
	if (get_user(flags, (int __user *) arg))

		return -EFAULT;



	return ovl_ioctl_set_flags(file, cmd, arg,

				   ovl_fsflags_to_iflags(flags));

	return ovl_ioctl_set_flags(file, cmd, arg, flags);

}



static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)

static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)

{

	unsigned int iflags = 0;

	unsigned int flags = 0;



	if (xflags & FS_XFLAG_SYNC)

		iflags |= S_SYNC;

		flags |= FS_SYNC_FL;

	if (xflags & FS_XFLAG_APPEND)

		iflags |= S_APPEND;

		flags |= FS_APPEND_FL;

	if (xflags & FS_XFLAG_IMMUTABLE)

		iflags |= S_IMMUTABLE;

		flags |= FS_IMMUTABLE_FL;

	if (xflags & FS_XFLAG_NOATIME)

		iflags |= S_NOATIME;

		flags |= FS_NOATIME_FL;



	return iflags;

	return flags;

}



static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
@@ -652,7 +650,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd, 
		return -EFAULT;



	return ovl_ioctl_set_flags(file, cmd, arg,

				   ovl_fsxflags_to_iflags(fa.fsx_xflags));

				   ovl_fsxflags_to_fsflags(fa.fsx_xflags));

}



long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

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