ext4 crypto: add missing locking for keyring_key access

Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/crypto_key.c b/fs/ext4/crypto_key.c
index c5882b36e5582d0005582d0fe3ac86cab70d9c9c..9a16d1e75a493f9e4663bb4ea05b9da9980ba65d 100644 (file)
--- 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: