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

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

[gregkh]

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 <stable@vger.kernel.org> know about it.


>From 8906a8223ad4909b391c5628f7991ebceda30e52 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Sat, 15 Oct 2016 09:48:50 -0400
Subject: fscrypto: lock inode while setting encryption policy

From: Eric Biggers <ebiggers@google.com>

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 <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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;
 }


Patches currently in stable-queue which might be from ebiggers@google.com 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