4.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Biggers <[email protected]> commit 8906a8223ad4909b391c5628f7991ebceda30e52 upstream. 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 <[email protected]> Signed-off-by: Theodore Ts'o <[email protected]> Reviewed-by: Richard Weinberger <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- fs/crypto/policy.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -109,6 +109,8 @@ int fscrypt_process_policy(struct file * 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 * ret = -EINVAL; } + inode_unlock(inode); + mnt_drop_write_file(filp); return ret; }
