From: Herbert Xu Date: Wed, 9 Apr 2025 03:29:03 +0000 (+0800) Subject: crypto: api - Allow delayed algorithm destruction X-Git-Tag: v6.16-rc1~206^2~278 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d701722aa343e59dd7c18fc62894edf4497251e2;p=thirdparty%2Fkernel%2Flinux.git 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: Sean Anderson Signed-off-by: Herbert Xu --- diff --git a/crypto/algapi.c b/crypto/algapi.c index 5b8a4c7873879..f368c0dc0d6d2 100644 --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -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);