From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 10 Dec 2015 05:57:58 +0000 (-0500)
Subject: ext4 crypto: add missing locking for keyring_key access
X-Git-Tag: submit/tizen/20160607.132125~1016
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b80b70ef40459ec9e7493cef5e91e4e11dad9e42;p=sdk%2Femulator%2Femulator-kernel.git

ext4 crypto: add missing locking for keyring_key access

commit db7730e3091a52c2fcd8fcc952b964d88998e675 upstream.

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

diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index c5882b3..9a16d1e 100644
--- 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: