Commit 6a480a78 authored by Al Viro's avatar Al Viro
Browse files

ecryptfs: fix handling of directory opening 



First of all, trying to open them r/w is idiocy; it's guaranteed to fail.
Moreover, assigning ->f_pos and assuming that everything will work is
blatantly broken - try that with e.g. tmpfs as underlying layer and watch
the fireworks.  There may be a non-trivial amount of state associated with
current IO position, well beyond the numeric offset.  Using the single
struct file associated with underlying inode is really not a good idea;
we ought to open one for each ecryptfs directory struct file.

Additionally, file_operations both for directories and non-directories are
full of pointless methods; non-directories should *not* have ->iterate(),
directories should not have ->flush(), ->fasync() and ->splice_read().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 10c64cea

fs/ecryptfs/file.c

+55 −16
Original line number Diff line number Diff line
@@ -112,7 +112,6 @@ static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) 
		.sb = inode->i_sb,

	};

	lower_file = ecryptfs_file_to_lower(file);

	lower_file->f_pos = ctx->pos;

	rc = iterate_dir(lower_file, &buf.ctx);

	ctx->pos = buf.ctx.pos;

	if (rc < 0)
@@ -223,14 +222,6 @@ static int ecryptfs_open(struct inode *inode, struct file *file) 
	}

	ecryptfs_set_file_lower(

		file, ecryptfs_inode_to_private(inode)->lower_file);

	if (d_is_dir(ecryptfs_dentry)) {

		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");

		mutex_lock(&crypt_stat->cs_mutex);

		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);

		mutex_unlock(&crypt_stat->cs_mutex);

		rc = 0;

		goto out;

	}

	rc = read_or_initialize_metadata(ecryptfs_dentry);

	if (rc)

		goto out_put;
@@ -247,6 +238,45 @@ out: 
	return rc;

}



/**

 * ecryptfs_dir_open

 * @inode: inode speciying file to open

 * @file: Structure to return filled in

 *

 * Opens the file specified by inode.

 *

 * Returns zero on success; non-zero otherwise

 */

static int ecryptfs_dir_open(struct inode *inode, struct file *file)

{

	struct dentry *ecryptfs_dentry = file->f_path.dentry;

	/* Private value of ecryptfs_dentry allocated in

	 * ecryptfs_lookup() */

	struct ecryptfs_file_info *file_info;

	struct file *lower_file;



	/* Released in ecryptfs_release or end of function if failure */

	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);

	ecryptfs_set_file_private(file, file_info);

	if (unlikely(!file_info)) {

		ecryptfs_printk(KERN_ERR,

				"Error attempting to allocate memory\n");

		return -ENOMEM;

	}

	lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),

				 file->f_flags, current_cred());

	if (IS_ERR(lower_file)) {

		printk(KERN_ERR "%s: Error attempting to initialize "

			"the lower file for the dentry with name "

			"[%pd]; rc = [%ld]\n", __func__,

			ecryptfs_dentry, PTR_ERR(lower_file));

		kmem_cache_free(ecryptfs_file_info_cache, file_info);

		return PTR_ERR(lower_file);

	}

	ecryptfs_set_file_lower(file, lower_file);

	return 0;

}



static int ecryptfs_flush(struct file *file, fl_owner_t td)

{

	struct file *lower_file = ecryptfs_file_to_lower(file);
@@ -267,6 +297,19 @@ static int ecryptfs_release(struct inode *inode, struct file *file) 
	return 0;

}



static int ecryptfs_dir_release(struct inode *inode, struct file *file)

{

	fput(ecryptfs_file_to_lower(file));

	kmem_cache_free(ecryptfs_file_info_cache,

			ecryptfs_file_to_private(file));

	return 0;

}



static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)

{

	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);

}



static int

ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)

{
@@ -346,20 +389,16 @@ const struct file_operations ecryptfs_dir_fops = { 
#ifdef CONFIG_COMPAT

	.compat_ioctl = ecryptfs_compat_ioctl,

#endif

	.open = ecryptfs_open,

	.flush = ecryptfs_flush,

	.release = ecryptfs_release,

	.open = ecryptfs_dir_open,

	.release = ecryptfs_dir_release,

	.fsync = ecryptfs_fsync,

	.fasync = ecryptfs_fasync,

	.splice_read = generic_file_splice_read,

	.llseek = default_llseek,

	.llseek = ecryptfs_dir_llseek,

};



const struct file_operations ecryptfs_main_fops = {

	.llseek = generic_file_llseek,

	.read_iter = ecryptfs_read_update_atime,

	.write_iter = generic_file_write_iter,

	.iterate = ecryptfs_readdir,

	.unlocked_ioctl = ecryptfs_unlocked_ioctl,

#ifdef CONFIG_COMPAT

	.compat_ioctl = ecryptfs_compat_ioctl,

CRA Git | Maintained and supported by SUSTech CRA and CCSE