Patch "fscrypto: lock inode while setting encryption policy" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

fscrypto: lock inode while setting encryption policy

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
fscrypto-lock-inode-while-setting-encryption-policy.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Eric Biggers <[email protected]>
Date: Sat, 15 Oct 2016 09:48:50 -0400
Subject: fscrypto: lock inode while setting encryption policy

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.

---
 fs/crypto/policy.c |    4 ++++
 1 file changed, 4 insertions(+)

@@ -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;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/fscrypto-lock-inode-while-setting-encryption-policy.patch queue-4.8/ext4-do-not-advertise-encryption-support-when-disabled.patch queue-4.8/fscrypto-make-xts-tweak-initialization-endian-independent.patch