Commit 8906a822 authored Oct 15, 2016 by Eric Biggers Committed by Theodore Ts'o Oct 15, 2016

fscrypto: lock inode while setting encryption policy



i_rwsem needs to be acquired while setting an encryption policy so that
concurrent calls to FS_IOC_SET_ENCRYPTION_POLICY are correctly
serialized (especially the ->get_context() + ->set_context() pair), and
so that new files cannot be created in the directory during or after the
->empty_dir() check.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Richard Weinberger <richard@nod.at>
Cc: stable@vger.kernel.org

parent 19962509

fs/crypto/policy.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -109,6 +109,8 @@ int fscrypt_process_policy(struct file *filp,
		if (ret)
		return ret;

		inode_lock(inode);

		if (!inode_has_encryption_context(inode)) {
		if (!S_ISDIR(inode->i_mode))
		ret = -EINVAL;
		@@ -127,6 +129,8 @@ int fscrypt_process_policy(struct file *filp,
		ret = -EINVAL;
		}

		inode_unlock(inode);

		mnt_drop_write_file(filp);
		return ret;
		}