Commit d701722a authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: api - Allow delayed algorithm destruction 



The current algorithm unregistration mechanism originated from
software crypto.  The code relies on module reference counts to
stop in-use algorithms from being unregistered.  Therefore if
the unregistration function is reached, it is assumed that the
module reference count has hit zero and thus the algorithm reference
count should be exactly 1.

This is completely broken for hardware devices, which can be
unplugged at random.

Fix this by allowing algorithms to be destroyed later if a destroy
callback is provided.

Reported-by: default avatarSean Anderson <sean.anderson@linux.dev>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent c80d6598

crypto/algapi.c

+4 −4
Original line number Diff line number Diff line
@@ -481,10 +481,10 @@ void crypto_unregister_alg(struct crypto_alg *alg) 
	if (WARN(ret, "Algorithm %s is not registered", alg->cra_driver_name))

		return;



	if (WARN_ON(refcount_read(&alg->cra_refcnt) != 1))

		return;



	if (alg->cra_type && alg->cra_type->destroy)

	if (alg->cra_destroy)

		crypto_alg_put(alg);

	else if (!WARN_ON(refcount_read(&alg->cra_refcnt) != 1) &&

		 alg->cra_type && alg->cra_type->destroy)

		alg->cra_type->destroy(alg);



	crypto_remove_final(&list);