Patch "fscrypto: add authorization check for setting encryption policy" has been added to the 4.4-stable tree

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

fscrypto: add authorization check for setting encryption policy

to the 4.4-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-add-authorization-check-for-setting-encryption-policy.patch
and it can be found in the queue-4.4 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: Thu, 8 Sep 2016 10:57:08 -0700
Subject: fscrypto: add authorization check for setting encryption policy

From: Eric Biggers <[email protected]>

commit 163ae1c6ad6299b19e22b4a35d5ab24a89791a98 upstream.

On an ext4 or f2fs filesystem with file encryption supported, a user could set an encryption policy on any empty directory(*) to which they had readonly access. This is obviously problematic, since such a directory might be owned by another user and the new encryption policy would prevent that other user from creating files in their own directory (for example).

Fix this by requiring inode_owner_or_capable() permission to set an encryption policy. This means that either the caller must own the file, or the caller must have the capability CAP_FOWNER.

(*) Or also on any regular file, for f2fs v4.6 and later and ext4
v4.8-rc1 and later; a separate bug fix is coming for that.

---
 fs/ext4/crypto_policy.c |    3 +++
 fs/f2fs/crypto_policy.c |    3 +++
 2 files changed, 6 insertions(+)

@@ -102,6 +102,9 @@ static int ext4_create_encryption_contex
 int ext4_process_policy(const struct ext4_encryption_policy *policy,
 			struct inode *inode)
 {
+	if (!inode_owner_or_capable(inode))
+		return -EACCES;
+
 	if (policy->version != 0)
 		return -EINVAL;
 

@@ -89,6 +89,9 @@ static int f2fs_create_encryption_contex
 int f2fs_process_policy(const struct f2fs_encryption_policy *policy,
 			struct inode *inode)
 {
+	if (!inode_owner_or_capable(inode))
+		return -EACCES;
+
 	if (policy->version != 0)
 		return -EINVAL;
 

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

queue-4.4/fscrypto-add-authorization-check-for-setting-encryption-policy.patch