Patch "ext4 crypto: add missing locking for keyring_key access" has been added to the 4.4-stable tree

Patch "ext4 crypto: add missing locking for keyring_key access" has been added to the 4.4-stable tree

[gregkh]

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

    ext4 crypto: add missing locking for keyring_key access

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:
     ext4-crypto-add-missing-locking-for-keyring_key-access.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 <stable@vger.kernel.org> know about it.


>From db7730e3091a52c2fcd8fcc952b964d88998e675 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 10 Dec 2015 00:57:58 -0500
Subject: ext4 crypto: add missing locking for keyring_key access

From: Theodore Ts'o <tytso@mit.edu>

commit db7730e3091a52c2fcd8fcc952b964d88998e675 upstream.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/crypto_key.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/fs/ext4/crypto_key.c
+++ b/fs/ext4/crypto_key.c
@@ -213,9 +213,11 @@ retry:
 		res = -ENOKEY;
 		goto out;
 	}
+	down_read(&keyring_key->sem);
 	ukp = user_key_payload(keyring_key);
 	if (ukp->datalen != sizeof(struct ext4_encryption_key)) {
 		res = -EINVAL;
+		up_read(&keyring_key->sem);
 		goto out;
 	}
 	master_key = (struct ext4_encryption_key *)ukp->data;
@@ -226,10 +228,12 @@ retry:
 			    "ext4: key size incorrect: %d\n",
 			    master_key->size);
 		res = -ENOKEY;
+		up_read(&keyring_key->sem);
 		goto out;
 	}
 	res = ext4_derive_key_aes(ctx.nonce, master_key->raw,
 				  raw_key);
+	up_read(&keyring_key->sem);
 	if (res)
 		goto out;
 got_key:


Patches currently in stable-queue which might be from tytso@mit.edu are

queue-4.4/ext4-crypto-add-missing-locking-for-keyring_key-access.patch