[CRYPTO] api: Fix potential race in crypto_remove_spawn

As it is crypto_remove_spawn may try to unregister an instance which is
yet to be registered.  This patch fixes this by checking whether the
instance has been registered before attempting to remove it.

It also removes a bogus cra_destroy check in crypto_register_instance as
1) it's outside the mutex;
2) we have a check in __crypto_register_alg already.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/algapi.c b/crypto/algapi.c
index 8ff8c2656d9c492902a5608436c145965f52723f..8383282de1ddc39422cd227b7a800a095ad14f67 100644 (file)
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -95,6 +95,9 @@ static void crypto_remove_spawn(struct crypto_spawn *spawn,
                return;
 
        inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
+       if (hlist_unhashed(&inst->list))
+               return;
+
        if (!tmpl || !crypto_tmpl_get(tmpl))
                return;
 
@@ -335,9 +338,6 @@ int crypto_register_instance(struct crypto_template *tmpl,
        LIST_HEAD(list);
        int err = -EINVAL;
 
-       if (inst->alg.cra_destroy)
-               goto err;
-
        err = crypto_check_alg(&inst->alg);
        if (err)
                goto err;