libceph: don't call crypto_free_sync_skcipher() on a NULL tfm

In set_secret(), key->tfm is assigned to NULL on line 55, and then
ceph_crypto_key_destroy(key) is executed.

ceph_crypto_key_destroy(key)
  crypto_free_sync_skcipher(key->tfm)
    crypto_free_skcipher(&tfm->base);

This happens to work because crypto_sync_skcipher is a trivial wrapper
around crypto_skcipher: &tfm->base is still 0 and crypto_free_skcipher()
handles that.  Let's not rely on the layout of crypto_sync_skcipher.

This bug is found by a static analysis tool STCheck written by us.

Fixes: 69d6302b65 ("libceph: Remove VLA usage of skcipher").
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Jia-Ju Bai 2019-07-24 17:43:06 +08:00 committed by Ilya Dryomov
parent a55aa89aab
commit e8c99200b4

View File

@ -136,8 +136,10 @@ void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
if (key) {
kfree(key->key);
key->key = NULL;
crypto_free_sync_skcipher(key->tfm);
key->tfm = NULL;
if (key->tfm) {
crypto_free_sync_skcipher(key->tfm);
key->tfm = NULL;
}
}
}