[PATCH 4.4 078/117] ext4 crypto: add missing locking for keyring_key access

Greg Kroah-Hartman
2016-02-15T00:29:43Z

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;